With Neutrino Masses Revealed, Proton Decay is the Missing Link
诺贝尔奖 突触囊泡.
2013诺贝尔奖】生理学奖深度解读：囊泡运输，细胞的“物流系统”Calo 2013-10-08 12:10一个细胞就好比一个人类社会。
人类社会有多复杂，细胞活动就有多精妙。
在日常生活中，我们需要进行有效率的生产生活，就必须有效率地调配生产资料与生活资源——因此，我们需要建立周密有效、安排得当的物流系统。
细胞也一样，基因的表达产物需要定位到不同的地点行使功能：膜蛋白需要奔向自己的靶位点、胰岛素需要分泌出细胞外、神经递质需要扩散到下一个神经细胞……要在正确的时间把正确的细胞货物运送到正确的目的地，细胞的物质转运机制之精妙，比无数物流师呕心沥血的杰作都更胜一筹。
而囊泡运输（vesicle trafficking），正是这一机制的重要组分。
2013年诺贝尔生理学或医学奖于10月7日颁布。
图片来源：昨天，2013年诺贝尔生理学或医学奖被授予发现囊泡转运机制的詹姆斯·罗斯曼、兰迪·谢克曼和托马斯·聚德霍夫3位科学家。
今天，让我们来看一下，大自然的物流师究竟是如何运筹于帷幄之中，决胜于细胞内外的呢？细胞中包括蛋白质在内的大多数分子都太大了，以致于不能直接穿过细胞中的膜结构。
于是，这些分子的运输需要依赖一种叫囊泡的细胞结构——这种有膜包被的小型泡状结构能够将待运输的分子包裹起来，送到目的地去释放掉。
可以想象，这种泡状的“集装箱”在运送细胞货物的过程中是极为重要的装备。
因此，在细胞中，尤其是在细胞质膜、内质网以及高尔基体中，囊泡的形成是持续不断的。
这些“集装箱”一旦被生产出来就马上投入使用，带着它们的货物奔向细胞内或细胞外的目的地。
囊泡之所以能够完成转运任务，是因为囊泡的膜与细胞质膜以及细胞内膜系统的组成成分是相似的，能够通过出芽的方式脱离转运起点、通过膜融合的方式归并到转运终点。
囊泡转运过程的第一步是膜通过出芽方式形成一个囊泡。
囊泡的外表面被蛋白包被。
通过改变膜结构的构象，这些蛋白将促使囊泡形成。
PACSnumbers1215Ff,1130Hv,1210Dm,1125Mj…
a r X i v :0803.2889v 2 [h e p -p h ] 14 J u l 2008Mapping Out SU (5)GUTs with Non-Abelian Discrete Flavor SymmetriesFlorian Plentinger ∗and Gerhart Seidl †Institut f¨u r Physik und Astrophysik,Universit¨a t W¨u rzburg,Am Hubland,D 97074W¨u rzburg,Germany(Dated:December 25,2013)We construct a class of supersymmetric SU (5)GUT models that produce nearly tribimaximal lepton mixing,the observed quark mixing matrix,and the quark and lepton masses,from discrete non-Abelian flavor symmetries.The SU (5)GUTs are formulated on five-dimensional throats in the flat limit and the neutrino masses become small due to the type-I seesaw mechanism.The discrete non-Abelian flavor symmetries are given by semi-direct products of cyclic groups that are broken at the infrared branes at the tip of the throats.As a result,we obtain SU (5)GUTs that provide a combined description of non-Abelian flavor symmetries and quark-lepton complementarity.PACS numbers:12.15.Ff,11.30.Hv,12.10.Dm,One possibility to explore the physics of grand unified theories (GUTs)[1,2]at low energies is to analyze the neutrino sector.This is due to the explanation of small neutrino masses via the seesaw mechanism [3,4],which is naturally incorporated in GUTs.In fact,from the perspective of quark-lepton unification,it is interesting to study in GUTs the drastic differences between the masses and mixings of quarks and leptons as revealed by current neutrino oscillation data.In recent years,there have been many attempts to re-produce a tribimaximal mixing form [5]for the leptonic Pontecorvo-Maki-Nakagawa-Sakata (PMNS)[6]mixing matrix U PMNS using non-Abelian discrete flavor symme-tries such as the tetrahedral [7]and double (or binary)tetrahedral [8]groupA 4≃Z 3⋉(Z 2×Z 2)and T ′≃Z 2⋉Q,(1)where Q is the quaternion group of order eight,or [9]∆(27)≃Z 3⋉(Z 3×Z 3),(2)which is a subgroup of SU (3)(for reviews see, e.g.,Ref.[10]).Existing models,however,have generally dif-ficulties to predict also the observed fermion mass hierar-chies as well as the Cabibbo-Kobayashi-Maskawa (CKM)quark mixing matrix V CKM [11],which applies especially to GUTs (for very recent examples,see Ref.[12]).An-other approach,on the other hand,is offered by the idea of quark-lepton complementarity (QLC),where the so-lar neutrino angle is a combination of maximal mixing and the Cabibbo angle θC [13].Subsequently,this has,in an interpretation of QLC [14,15],led to a machine-aided survey of several thousand lepton flavor models for nearly tribimaximal lepton mixing [16].Here,we investigate the embedding of the models found in Ref.[16]into five-dimensional (5D)supersym-metric (SUSY)SU (5)GUTs.The hierarchical pattern of quark and lepton masses,V CKM ,and nearly tribi-maximal lepton mixing,arise from the local breaking of non-Abelian discrete flavor symmetries in the extra-dimensional geometry.This has the advantage that theFIG.1:SUSY SU (5)GUT on two 5D intervals or throats.The zero modes of the matter fields 10i ,5H,24H ,and the gauge supermul-tiplet,propagate freely in the two throats.scalar sector of these models is extremely simple without the need for a vacuum alignment mechanism,while of-fering an intuitive geometrical interpretation of the non-Abelian flavor symmetries.As a consequence,we obtain,for the first time,a realization of non-Abelian flavor sym-metries and QLC in SU (5)GUTs.We will describe our models by considering a specific minimal realization as an example.The main features of this example model,however,should be viewed as generic and representative for a large class of possible realiza-tions.Our model is given by a SUSY SU (5)GUT in 5D flat space,which is defined on two 5D intervals that have been glued together at a common endpoint.The geom-etry and the location of the 5D hypermultiplets in the model is depicted in FIG.1.The two intervals consti-tute a simple example for a two-throat setup in the flat limit (see,e.g.,Refs.[17,18]),where the two 5D inter-vals,or throats,have the lengths πR 1and πR 2,and the coordinates y 1∈[0,πR 1]and y 2∈[0,πR 2].The point at y 1=y 2=0is called ultraviolet (UV)brane,whereas the two endpoints at y 1=πR 1and y 2=πR 2will be referred to as infrared (IR)branes.The throats are supposed to be GUT-scale sized,i.e.1/R 1,2 M GUT ≃1016GeV,and the SU (5)gauge supermultiplet and the Higgs hy-permultiplets 5H and2neously broken to G SM by a 24H bulk Higgs hypermulti-plet propagating in the two throats that acquires a vac-uum expectation value pointing in the hypercharge direc-tion 24H ∝diag(−12,13,15i ,where i =1,2,3is the generation index.Toobtainsmall neutrino masses via the type-I seesaw mechanism [3],we introduce three right-handed SU (5)singlet neutrino superfields 1i .The 5D Lagrangian for the Yukawa couplings of the zero mode fermions then readsL 5D =d 2θ δ(y 1−πR 1) ˜Y uij,R 110i 10j 5H +˜Y d ij,R 110i 5H +˜Y νij,R 15j5i 1j 5H +M R ˜Y R ij,R 21i 1j+h.c. ,(3)where ˜Y x ij,R 1and ˜Y x ij,R 2(x =u,d,ν,R )are Yukawa cou-pling matrices (with mass dimension −1/2)and M R ≃1014GeV is the B −L breaking scale.In the four-dimensional (4D)low energy effective theory,L 5D gives rise to the 4D Yukawa couplingsL 4D =d 2θ Y u ij 10i 10j 5H +Y dij10i 5H +Y νij5i ∼(q i 1,q i 2,...,q i m ),(5)1i ∼(r i 1,r i 2,...,r im ),where the j th entry in each row vector denotes the Z n jcharge of the representation.In the 5D theory,we sup-pose that the group G A is spontaneously broken by singly charged flavon fields located at the IR branes.The Yukawa coupling matrices of quarks and leptons are then generated by the Froggatt-Nielsen mechanism [21].Applying a straightforward generalization of the flavor group space scan in Ref.[16]to the SU (5)×G A represen-tations in Eq.(5),we find a large number of about 4×102flavor models that produce the hierarchies of quark and lepton masses and yield the CKM and PMNS mixing angles in perfect agreement with current data.A distri-bution of these models as a function of the group G A for increasing group order is shown in FIG.2.The selection criteria for the flavor models are as follows:First,all models have to be consistent with the quark and charged3 lepton mass ratiosm u:m c:m t=ǫ6:ǫ4:1,m d:m s:m b=ǫ4:ǫ2:1,(6)m e:mµ:mτ=ǫ4:ǫ2:1,and a normal hierarchical neutrino mass spectrumm1:m2:m3=ǫ2:ǫ:1,(7)whereǫ≃θC≃0.2is of the order of the Cabibbo angle.Second,each model has to reproduce the CKM anglesV us∼ǫ,V cb∼ǫ2,V ub∼ǫ3,(8)as well as nearly tribimaximal lepton mixing at3σCLwith an extremely small reactor angle 1◦.In perform-ing the group space scan,we have restricted ourselves togroups G A with orders roughly up to 102and FIG.2shows only groups admitting more than three valid mod-els.In FIG.2,we can observe the general trend thatwith increasing group order the number of valid modelsper group generally increases too.This rough observa-tion,however,is modified by a large“periodic”fluctu-ation of the number of models,which possibly singlesout certain groups G A as particularly interesting.Thehighly populated groups would deserve further system-atic investigation,which is,however,beyond the scopeof this paper.From this large set of models,let us choose the groupG A=Z3×Z8×Z9and,in the notation of Eq.(5),thecharge assignment101∼(1,1,6),102∼(0,3,1),103∼(0,0,0),52∼(0,7,0),52↔4FIG.3:Effect of the non-Abelian flavor symmetry on θ23for a 10%variation of all Yukawa couplings.Shown is θ23as a function of ǫfor the flavor group G A (left)and G A ⋉G B (right).The right plot illustrates the exact prediction of the zeroth order term π/4in the expansion θ23=π/4+ǫ/√2and the relation θ13≃ǫ2.The important point is that in the expression for θ23,the leading order term π/4is exactly predicted by thenon-Abelian flavor symmetry G F =G A ⋉G B (see FIG.3),while θ13≃θ2C is extremely small due to a suppression by the square of the Cabibbo angle.We thus predict a devi-ation ∼ǫ/√2,which is the well-known QLC relation for the solar angle.There have been attempts in the literature to reproduce QLC in quark-lepton unified models [26],however,the model presented here is the first realization of QLC in an SU (5)GUT.Although our analysis has been carried out for the CP conserving case,a simple numerical study shows that CP violating phases (cf.Ref.[27])relevant for neutri-noless double beta decay and leptogenesis can be easily included as well.Concerning proton decay,note that since SU (5)is bro-ken by a bulk Higgs field,the broken gauge boson masses are ≃M GUT .Therefore,all fermion zero modes can be localized at the IR branes of the throats without intro-ducing rapid proton decay through d =6operators.To achieve doublet-triplet splitting and suppress d =5pro-ton decay,we may then,e.g.,resort to suitable extensions of the Higgs sector [28].Moreover,although the flavor symmetry G F is global,quantum gravity effects might require G F to be gauged [29].Anomalies can then be canceled by Chern-Simons terms in the 5D bulk.We emphasize that the above discussion is focussed on a specific minimal example realization of the model.Many SU (5)GUTs with non-Abelian flavor symmetries,however,can be constructed along the same lines by varying the flavor charge assignment,choosing different groups G F ,or by modifying the throat geometry.A de-tailed analysis of these models and variations thereof will be presented in a future publication [30].To summarize,we have discussed the construction of 5D SUSY SU (5)GUTs that yield nearly tribimaximal lepton mixing,as well as the observed CKM mixing matrix,together with the hierarchy of quark and lepton masses.Small neutrino masses are generated only by the type-I seesaw mechanism.The fermion masses and mixings arise from the local breaking of non-Abelian flavor symmetries at the IR branes of a flat multi-throat geometry.For an example realization,we have shown that the non-Abelian flavor symmetries can exactly predict the leading order term π/4in the sum rule for the atmospheric mixing angle,while strongly suppress-ing the reactor angle.This makes this class of models testable in future neutrino oscillation experiments.In addition,we arrive,for the first time,at a combined description of QLC and non-Abelian flavor symmetries in SU (5)GUTs.One main advantage of our setup with throats is that the necessary symmetry breaking can be realized with a very simple Higgs sector and that it can be applied to and generalized for a large class of unified models.We would like to thank T.Ohl for useful comments.The research of F.P.is supported by Research Train-ing Group 1147“Theoretical Astrophysics and Particle Physics ”of Deutsche Forschungsgemeinschaft.G.S.is supported by the Federal Ministry of Education and Re-search (BMBF)under contract number 05HT6WWA.∗********************************.de †**************************.de[1]H.Georgi and S.L.Glashow,Phys.Rev.Lett.32,438(1974);H.Georgi,in Proceedings of Coral Gables 1975,Theories and Experiments in High Energy Physics ,New York,1975.[2]J.C.Pati and A.Salam,Phys.Rev.D 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On the determination of CP violating Majorana phases
(5)
or of the products of Jγk . For three generations, there are nine of such invariants Jγk but the unitarity of U makes all of them have the same imaginary component including the sign Im [Jγk ] = J = c1 c2 c2 3 s1 s2 s3 sin δ. (6)
The phase δ can be determined once one knows J and the mixing angles. Recently there have been many studies [5] where extracting J from the long-baseline three-flavour neutrino oscillations experiments is discussed. Existing 2 neutrino anomalies imply [6] three different scales of neutrino mass squared differences δm2 ≡ (m2 j − mk ):
On the determination of CP violating Majorana phases
M K Samal∗
Institute of Physics, Sachivalaya Marg, Bhubaneswar 751 005, India. The determination of CP violating phases in the Majorana neutrino mixing matrix using phenomenological constraints from neutrino oscillations, neutrinoless double beta decay, (µ− , e+ ) conversion and few other processes is discussed. We give the expressions for the phases in terms of the mixing angles and masses consistent with the recent data from Kamiokande.
人体结构学 Human Structure学习通章节答案期末考试题库2023年
人体结构学 Human Structure学习通超星课后章节答案期末考试题库2023年1.Which bones belong to the shoulder girdle?答案:Scapula###Clavicle2.The paired cerebral bones are答案:parietal bone###temporal bone3.Shoulder joint is formed by答案:head of humerus###glenoid cavity of scapula4.Please deseribe the location and openings of the paranasal sinuses答案:答5.Please describe the formation, main structures and communications of the middle Cranial fossa.答案:答6.Please describe the joints of the vertebral bodies.答案:答7.Please describe the joints of the vertebral arches.答案:答8.Please describe the composition, characteristics and movements of theshoulder joint.答案:答9.Which bone belongs to the long bone?答案:Femur10.Which bones belong to the irregular bone?答案:Vertebra###Sphenoid bone11.The blood- testis barrier does NOT include the答案:gap junction between adjacent spermatogomia12.Which of the following description is true about the primordial follicles答案:The primordial follicle consists of a primary oocyte and a layer of flat follicle cells.13.(英文答题,第一空填1个单词,第二空3个单词)The axial bone contains fromup downwards _____ and_____.答案:skull###bonesoftrunk14.About the component of nephron, the correct option is答案:renal corpuscle, proximal tubules, distal tubules and thin segment15.About the features of proximal tubule, the WRONG option is答案:The cytoplasm of epithelial cell is weakly basophilic.16. A patient presents in your office after having a positive result on a homepregnancy test. Her menstrual cycle has always been the classic 28-day cycle discussed in textbooks, with ovulation occurring on the 14th day following the start of menstruation. Her menstrual period began on August 19.2019.You estimate her EDD to be答案:on May 26, 202017.Which of the following is NOT considered one of the fetal membranes答案:buccopharyngeal membrane18.Which bone does not form the anterior cranial fossa?答案:Temporal bone19.Which bone forms both the middle and posterior cranial fossa?答案:Temporal bone20.(英文答题,第一空填1个单词,第二空1个单词,第三空2个单词)Thesternum consists from up downwards of_____ , _______ and ______ .答案:manubrium###body###xiphoidprocess21.Of the following statements about epididymis, the WRONG option is答案:The ductus epididymis is lined with a simple columnar epithelium22.Of the following statements about trachea, the WRONG option is答案:The adventitia is constructed of the elastic cartilage rings.23.The interalveolar septum does NOT contain答案:ciliated cell24.All the following cells are included in the spermatogenic epithelium, EXCEPTthe答案:Leydig cells25.Please describe the general features of the vertebrae.答案:答26.Which bone forms the posteroinferior part of the bony nasal septum?答案:Vomer27.Drawing pictures of Thoracic vertebra from anterior and lateral view.答案:答28.Which bone does not form the thoracic Cage?答案:Sacrum29.About the scapula, which of the statements is not true?答案:It has three borders, three angles and three surfaces.30.About the component of the renal corpuscle, the WRONG option is答案:At the vascular pole, the efferent arteriole enters the glomerulus.31.Of the following statements about podocyte, the correct option is答案:They form the visceral layer of the Bowman's capsule.32.An infant is born with a sacrococcygeal teratoma. Biopsy(组织活检) andhistologic analysis reveal that it contains intestinal epithelia, cardiac muscle, cartilage, and integument tissue. You counsel the mother that the tumor is benign（良性的）and recommend surgical removal. This tumor was caused by which developmental anomaly?答案:Failure of primitive streak regression33.Which of the following structure is NOT included in the secondary follicle?答案:secondary oocyte34.All the following are from mesoderm EXCEPT the答案:spinal cord35.Which of the following descriptions is NOT true about the corpus luteum?答案:The corpus luteum continues to produce estrogen and progesterone during the whole process of pregnancy.36.Of the following statements about the alveolus of lung, the WRONG option is答案:It opens on the wall of terminal bronchioles.37.Which of the following descriptions is NOT true about the secretory phase ofa menstrual cycle?答案:The basal layer of endometrium becomes thicker .38.Of the following statements about Leydig cells, the correct option is答案:It secretes testosterone.39.Of the following statements about macula densa, the WRONG option is答案:It is derived from smooth muscle fibers of afferent arteriole.40.Of the following statements concerning terminal bronchioles, the WRONGoption is答案:They have some mixed gland.41.Of the following options, the blood-air barrier does NOT contain答案:typeⅡalveolar cells42.All the following cells are included in the spermatogenic cells, EXCEPT答案:Sertoli cells43.Which of the following does not belong to the joints of the vertebral arches?答案:Anterior longitudinal ligament44.Human chorionic gonadotropin is produced by the答案:syncytiotrophoblast45.Which of the followings is not enclosed in the articular capsule of shoulderjoint ?答案:Tendon of the short head of the biceps46.The pathway connecting the infratemporal fossa with the orbit is答案:inferior orbital fissure47.When does ovulation occur in a menstrual cycle?答案:the 14th day。
非酒精性脂肪性肝病代谢组学研究进展
机制尚未完全明确，１９９８ 年Ｄａｙ 等［１２］提出“二次打击”学说。 开。同时ＮＡＦＬＤ 肝硬化患者与酒精性肝硬化患者也可有效区
随后Ｔｉｌｇ 等［１３ －１４］提出“多重平行打击”理论，包括遗传因素、 分开（ＡＵＣ ＝０． ８３）。他们认为此方法可作为区分ＮＡＦＬＤ 纤维
ＩＲ、氧化应激、脂毒性、慢性炎症、纤维化、免疫和肠道菌群等， 化程度及诊断的无创生物标志物，且可以显著减少对肝活检的
黄酯和１３ － ｃｉｓＲＡ 呈正相关。他们在人类组织中首次检测到 验证；单不饱和ＴＡＧ 的增加可能是ＮＡＦＬＤ 和ＣＨＢ 患者ＮＡＳＨ
ａｔＲＡ 的活性代谢物４ － ｏｘｏ － ａｔＲＡ，表明这种类维生素Ａ 可能 的特异性标志物。
有助于人体类维生素Ａ 的信号传导。肝脏维生素Ａ 的稳态平 ２． ３ 代谢组学对ＮＡＦＬＤ 药物作用与疗效研究的推动作用
录组学、蛋白质组学为代表的系统生物学技术提供了新的技术 展的新学科，代谢组学较为全面的展示了机体的代谢结果，为
与思路。区别于其他组学技术，以内源性小分子代谢物为研究 临床医学提供了新的技术和方法。
对象的代谢组学可以很好的揭示机体变化的最终代谢结果。因 ２ 非酒精性脂肪性肝病（ＮＡＦＬＤ）
收 基 作ＤＯ稿 金 者Ｉ：日 项 简１０期 目 介． ３：：：９１２上 栾研６７０９）２海究雨／０ｊ．中婷－ｉｓ医１ｓ（ｎ１药．１－１９大０９０００６学１—；修－附）５回，属２女５日第６，．期七主２０：人２要２１０民．２从００医４事－．院０１慢４２人７－性才１肝７培病养计的划基（础ＸＸ与２０临１９床－ 通信作者：顼志兵，ｘｚｂ６１６０＠ １６３． ｃｏｍ
和遗传易感密切相关的代谢应激性肝损伤，包括非酒精性单纯 １ 代谢组学概述
性肝脂肪变（ＮＡＦＬ）、非酒精性脂肪性肝炎（ＮＡＳＨ）、肝硬化和 １． １ 代谢组学含义 代谢组学最初于１９９９ 年由Ｎｉｃｈｏｌｓｏｎ
TASI 2002 lectures on neutrinos
1
I.
INTRODUCTION
The success of the Standard Model (SM) can be seen as a proof that it is an effective low energy description of Nature. We are therefore interested in probing the more fundamental theory. One way to go is to search for new particles that can be produced in yet unreached energies. Another way to look for new physics is to search for indirect effects of heavy unknown particles. In this set of lectures we explain how neutrino physics is used to probe such indirect signals of physics beyond the SM. In the SM the neutrinos are exactly massless. This prediction, however, is rather specific to the SM. In almost all of the SM extensions the neutrinos are massive and they mix. The search for neutrino flavor oscillation, a phenomenon which is possible only for massive neutrinos, is a search for new physics beyond the SM. The recent experimental indications for neutrino oscillations are indirect evidences for new physics, most likely, at distances much shorter than the weak scale. In the first lecture the basic mechanisms for generating neutrino masses are described and the ingredients of the SM that ensure massless neutrinos are explained. Then, the neutrino oscillation formalism is developed. In the second lecture the current experimental situation is summarized. In particular, we describe the oscillation signals observed by solar neutrino experiments, atmospheric neutrino experiments and long baseline terrestrial neutrino experiments. Each of these results separately can be accounted for by a rather simple modification to the SM. Trying to accommodate all of them simultaneously, however, is not trivial. In the third lecture we explain what are the theoretical challenges in trying to combine all the experimental indications for neutrino masses, and give several examples of models that cope with some of these challenges. These lecture notes are aimed to provide an introduction to the topic of neutrino physics. They are not meant to be a review. Therefore, many details are not given and many references are omitted. There are many textbooks [1] and reviews [2–4] about neutrinos. There is also a lot of information about neutrinos on the web [5, 6]. All these sources provide more detailed discussions with complete set of references on the topics covered in these lectures. Moreover, they also cover many subjects that are not mentioned here. In preparing the lectures I used mainly the recent review by Gonzalez-Garcia and Nir [4]. This review is a very good starting point to anyone who wants to learn more about neutrino physics.
Neutrino Mass Spectrum and Future Beta Decay Experiments
c,d ‡
Scuola Internazionale superiore di Studi Avanzati via Beirut 4, I,34014 Trieste, Italy
b
Instituto de F´ ısica Gleb Wataghin, Universidade Estadual de Campinas, UNICAMP 13083-970 Campinas SP, Brazil The Abdus Salam International Centre for Theoretical Physics, I-34100 Trieste,Italy
hep-ph/0105105 February 1, 2008
Neutrino Mass Spectrum and Future Beta Decay Experiments
arXiv:hep-ph/0105105v3 26 May 2001
Y. Farzan
a
a ∗
, O. L. G. Peres
spectrum, one can put an upper bound on the neutrino mass assuming, however, that there is no conspiracy which leads to cancellation of different effects [4]. Therefore independent measurements of the neutrino mass are needed and their results will be used in the analysis of the cosmological data as an input deduced from particle physics. Several methods have been proposed to determine neutrino masses by using the supernova neutrino data. One method is based on searches for the energy ordering of events which has, however, rather low sensitivity [5]. The limits on the mass can be also obtained from observations of sharp time structures in the signals. It was suggested to study the time distribution of detected neutrino events emitted from supernova which entails to black hole formation [6]. By this method Super-Kamiokande can measure values of the νe mass down to 1.8 eV and SNO can put an upper bound 20 eV on the νµ and ντ masses [6] . (Clearly this bound on the νµ and ντ masses is much weaker than bounds implied by combined analysis of the solar and atmospheric neutrino data and direct measurements of the νe mass.) In this case one can check the still non-excluded possibility in which the solar neutrino problem is solved by the oscillations to sterile neutrino and the masses of νµ and ντ are in 20 eV range. (Such neutrinos should be unstable in cosmological time.) The absolute values of the neutrino masses can be determined in the assumption that the cosmic rays with energies above the GZK cutoff are produced in annihilation of the ultra-high energy neutrinos with the cosmological relic neutrinos [7, 8, 9]. The analysis of the observed energy spectrum of cosmic rays above 1020 eV gives the mass mν = (1.5 − 3.6) eV, if the power-like part of the ultra-high energy cosmic rays spectrum is produced in Galactic halo, and mν = (0.12 − 0.46) eV, if this part has the extragalactic origin [10]. Neutrinoless double beta decay (2β 0ν ) searches are sensitive to the Majorana mass of the electron neutrino. However, in the presence of mixing the situation can be rather complicated: The effective Majorana mass of νe relevant for the 2β 0ν -decay, mee , is a combination of mass eigenvalues and mixing parameters given by mee =
Accomodating Solar and Atmospheric Neutrino Deficits, Hot Dark Matter, and a Double Beta De
arXiv:hep-ph/9402231v2 9 Feb 1994
−6 2 2 −3 a)Small − angle MSW, ∆m2 ei ∼ 6 × 10 eV , sin 2θei ∼ 7 × 10 ,
2
−6 2 2 b)Large − angle MSW, ∆m2 ei ∼ 9 × 10 eV , sin 2θei ∼ 0.6, −10 eV2 , sin2 2θ ∼ 0.9. c)Vacuum oscillation, ∆m2 ei ei ∼ 10
(1)
Of these, (a) is favored over (b) by the fits to the solar neutrino data [9], and both (b) and (c) are disfavored by information from the neutrino burst from supernova 1987A [11]. B. Atmospheric Neutrino Deficit The second set of experiments indicating non-zero neutrino masses and mixings has to do with atmospheric νµ ’s and νe ’s arising from the decays of π ’s and K ’s and the subsequent decays of secondary muons produced in the final states of the π and K decays. In the underground experiments the νµ and ν ¯µ produce muons and the νe and ν ¯e lead to e± . Observations of µ± and e± indicate a far lower value for νµ and ν ¯µ than suggested by na¨ ıve counting arguments which imply that N (νµ + ν ¯µ ) = 2N (νe + ν ¯e ). More precisely, the ratio of µ events to e-events can be normalized to the ratio of calculated fluxes to reduce flux uncertainties, giving [3] R(µ/e) = 0.60 ± 0.07 ± 0.05 (Kamiokande), = 0.54 ± 0.05 ± 0.12 (IMB), = 0.69 ± 0.19 ± 0.09 (Soudan II). Combining these results with observations of upward going muons by Kamiokande [3], IMB [3], and Baksan [12] and the negative Fr´ ejus [13] and NUSEX [14] results leads to the conclusion [15] that neutrino oscillations can give an explanation of these results, provided
Supersymmetric Neutrino Masses and Mixing with R-parity Violation
[9] [5, 10] [7]
(1) (2) (3)
With ordinary three neutrinos, any two of the mass-squared differences in the above equations can be obtained: that is, those corresponding to (i) solar and atmospheric (S+A), (ii) solar and LSND (S+L), or (iii) atmospheric and LSND (A+L) neutrino data. For (S+A), the LSND result has to be disregarded. In the case of (S+L) or (A+L), the presence of a sterile neutrino is necessary for the explanation of the atmospheric or solar neutrino experiment, respectively. One of the desirable features of the supersymmetric extension of the standard model would be the generation of small neutrino masses within its context, as the supersymmetric standard model with the minimal particle content (MSSM) allows for the lepton (L) and baryon number (B) violating operators. In order to ensure the longevity of a proton, one usually assumes the conservation of R-parity, forbidding both (renormalizable) B and L violating operators. As a consequence, the lightest supersymmetric particle (LSP) is stable and thus cold dark matter of the universe may consist of neutral LSP’s. However, there is no obvious theoretical reason why R-parity needs to be conserved, or why both B and L conservation have to be imposed. L-violation would be present in the MSSM and it may be the origin of nonzero neutrino masses and mixing that explain current experimental data, while proton stability is ensured by B conservation alone. The L-violating operators in the MSSM are µi Li H2 ,
Standard Model
1 Historical background
The Standard Model of elementary particles (more schematic depiction), with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.
3.1 Fermions
quarks being very strongly bound to one another, forming color-neutral composite particles (hadrons) containing either a quark and an antiquark (mesons) or three quarks (baryons). The familiar proton and the neutron are the two baryons having the smallest mass. Quarks also carry electric charge and weak isospin. Hence they interact with other fermions both electromagnetically and via the weak interaction.
Standard Model
This article is about the Standard Model of particle physics. For other uses, see Standard model (disambiguation). This article is a non-mathematical general overview of the Standard Model. For a mathematical description, see the article Standard Model (mathematical formulation). For the Standard Model of Big Bang cosmology, Lambda-CDM model. The Standard Model of particle physics is a theory con-
云南省2016-2019年男男性行为者HIV感染影响因素分析
DOI: 10.13419/ki.aids.2021.03.17•工作研究•云南省2016 —2019年男男性行为者HIV感染影响因素分析张祖样、宋丽军：，肖民扬'，李雪华牛瑾1，付丽茹1，王晓雯、罗红兵1(I.幺南省疾病预防控制中心，昆明650034: 2.云南宵艾滋病研究所，昆明650034)摘要：目的了解2016—2019年a•南省男男性行为#(MSM)的艾滋病病毒（l_IIY)感染现况，分析有关影响因素方法每年4_7月通过滚雪球，网络招募等方法对各地MSM进行横断面调査结果2016 —2019年MSM的 HIV感染率分别为7.7%(2丨5/2 785)、7.5%(2丨2/2.822)、7.3%(197/2 7丨4>、6.6%(175/2 632) 2016—2019年 MSM最近 6个月发生同性肛交性行为时坚持使用安全套的比例为73.5%〜75.9% ,最近6个月发生异性性行为坚持使用安全套比例38.0%~47.9%,艾滋病知识知晓率％.0%~97.5%、接受过干预服务比例91.2%~97.7%._,丨丨IV感染影响W素分析结 果:连续4年的共同危险因索包括30〜39岁、少数民族、近6个月发生同性性行为未坚持使用安全套；连续3年的共同 危险W索：20〜29岁、最近一年被诊断患性病.结论云南省MSM的HIY感染率较高，存在知行分离应探索干预新模式和新方法，重点关注青年和少数民族MSM,尤其是安全套使用依从性差者和性病患者加强安全套使用在预防艾滋病感染风险中益处的宣传教育，提高安全套使川比例，降低暴露风险关键词：男男性行为者；艾滋病；影响因素中图分类号：R 373.9 文献标志码：A文章编号：1672-5662(2021 )03-0284-04HIV infection rate and influencing factors among MSM during 2016-2019 in Yunnan province Z H A N G Z u ya n g', S O N G L iju tr, X IA O M in y a n g', L I X u e h u a', N1U J in', F U Liru', W A N G X ia o w e n1, L U O H o n g b in g'. (I. Yunnan P ro v in c ia l C e n te r f o r D ise a se P re ve n tio n a n d C ontrol, K u n m in g650034, C h in a; 2. Yunnan P ro v in c ia l A ID S R esea rch In stitu te, K u n m in g650034)Correspondingauthor:LUOHongbing,Email:****************Supported by the National Science and Technology Major Project of the 13th Five-Year Plan (2017ZX1020110100211);the National Science and Technology Major Project of China (2018ZX10715006)Abstract: Objective To understand the status of HIV infection and influencing factors among men who have sex with men (MSM) in Yunnan province during 2016-2019. Methods During the surveillance period of April to July each year, cross-sectional surveys were perfomied by using snowball sampling method and online recruitment. Results The HIV infection rates of MSM during 2016-2019 were 7.7% (215/2 785), 7.2% (212/2 822), 7.3% (197/2 714), and 6.6% (175/2 632), with no significant difference 571, P=0.463). The proportion of consistent condom use among MSM in homosexual anal sex in the last 6 months was 73.5%-75.9%, and that in the heterosexual behavior was 38.0%-47.9%, the awareness rate of AIDS knowledge was 96.0%-97.5 %, and the rate of received intervention services was 91.2%-97.7%.The common risk factors for the 4 consecutive years included the age of 30-39 years, ethnic minorities, and failure to use condoms in homosexual behavior in the past six months. The common risk factors for 3 years included the age of 20-29 years, and being diagnosed as STDs in the last year. Conclusion There is high HIV infection among MSM in Yunnan, and a gap between knowledge awareness and safe sex behavior. Intervention should be strengthened and focus on the young and ethnic groups, especially those with no consistent condom use and suffering STDs.Keywords: MSM; HIV; Influencing factors收稿日期.•2020-05-03;修回日期：2020-12-29基金项目：国家“十三五”重大专项（2017Z X10201101002011>;国家科技重大t•项（20丨8Z X丨07丨5006)第一作者简介：张祖样（丨990 _)，女，云南省德宏州人，医师，从事艾滋病投情监测T.作Emaihzzy200917005@ 宋丽军（1982—)，女，山两省长治市人，主管陕师，从事艾滋病 监测丁.作 _Email:丨3767974@(丨q.(.om张祖样与宋丽军为并列第一作者。
暴涨宇宙学与暗能量
Dark Energy and neutrinos：
Any connection between Dark Energy and neutrinos? 1. ΛCDM: (10 ev) (m ) m 2. QCDM: m 10 eV M
II.
Implications in CMB: W. Hu astro-ph/0410680 R. Caldwell and Doran: astro-ph/0501104 G. Zhao, J. Xia, M. Li, B. Feng and X. Zhang: astro-ph/0507482
III. Different from cosmological constant, Quintessence and Phantom in the determination of the evolutions and the fate of the universe A lot of studies on the evolution of UNIVERSE with w across -1 just give one example: Oscillating Quintom
Two comments: 1. Parameterization dependent 2. Effects of perturbations
w( z ) w0 w1 z
Astro-ph/0507170
Astro-ph/0507482
W1 = 20
On the physics of massive neutrinos
The eigenvalues of γ5 (chirality) agree with those of helicity in the massless case. Here the Dirac equation decouples into two seperate equations for ψL,R 2
respectively. An alternative 2-component description was developed by Majorana [6] to describe a particle identical to its antiparticle. If neutrinos acquire a mass, in general both helicity states for neutrinos and antineutrinos can exist, making a 4-component description necessary. Here a 4-component Dirac-spinor can be treated as a sum of two 2-component Weyl-spinors or as composed out of two degenerated Majorana neutrinos. However it is still an open question whether neutrinos are Dirac or Majorana particles. The Majorana condition, for a particle to be its own antiparticle, can be written as
2.1 Weyl-, Majorana- and Dirac-neutrinos The neutrino states observed in weak interactions are neutrinos with helicity -1 and antineutrinos with helicity +1. For massless neutrinos and the absence of right-handed currents there is no chance to distinguish between Dirac- and Majorana neutrinos . Because V-A theory is maximal parity violating the other two states (neutrinos with helicity +1 and antineutrinos with helicity -1), if they exist, are unobservable. If neutrinos are massless a 2-component spinor (Weyl-spinor) is sufficient for description, first discussed for the general case of massless spin 1/2 particles by Weyl [5], which are the helicity -1(+1) projections for particles (antiparticles) out of a 4-component spinor Ψ. They are given by 1 ΨL,R = (1 ± γ5 )Ψ 2 (1)
开启片剂完整性的窗户(中英文对照)
开启片剂完整性的窗户日本东芝公司，剑桥大学摘要：由日本东芝公司和剑桥大学合作成立的公司向《医药技术》解释了FDA支持的技术如何在不损坏片剂的情况下测定其完整性。
太赫脉冲成像的一个应用是检查肠溶制剂的完整性，以确保它们在到达肠溶之前不会溶解。
关键词：片剂完整性，太赫脉冲成像。
能够检测片剂的结构完整性和化学成分而无需将它们打碎的一种技术，已经通过了概念验证阶段，正在进行法规申请。
由英国私募Teraview公司研发并且以太赫光（介于无线电波和光波之间）为基础。
该成像技术为配方研发和质量控制中的湿溶出试验提供了一个更好的选择。
该技术还可以缩短新产品的研发时间，并且根据厂商的情况，随时间推移甚至可能发展成为一个用于制药生产线的实时片剂检测系统。
TPI技术通过发射太赫射线绘制出片剂和涂层厚度的三维差异图谱，在有结构或化学变化时太赫射线被反射回。
反射脉冲的时间延迟累加成该片剂的三维图像。
该系统使用太赫发射极，采用一个机器臂捡起片剂并且使其通过太赫光束，用一个扫描仪收集反射光并且建成三维图像(见图)。
技术研发太赫技术发源于二十世纪九十年代中期13本东芝公司位于英国的东芝欧洲研究中心，该中心与剑桥大学的物理学系有着密切的联系。
日本东芝公司当时正在研究新一代的半导体，研究的副产品是发现了这些半导体实际上是太赫光非常好的发射源和检测器。
二十世纪九十年代后期，日本东芝公司授权研究小组寻求该技术可能的应用，包括成像和化学传感光谱学，并与葛兰素史克和辉瑞以及其它公司建立了关系，以探讨其在制药业的应用。
虽然早期的结果表明该技术有前景，但日本东芝公司却不愿深入研究下去，原因是此应用与日本东芝公司在消费电子行业的任何业务兴趣都没有交叉。
这一决定的结果是研究中心的首席执行官DonArnone和剑桥桥大学物理学系的教授Michael Pepper先生于2001年成立了Teraview公司一作为研究中心的子公司。
TPI imaga 2000是第一个商品化太赫成像系统，该系统经优化用于成品片剂及其核心完整性和性能的无破坏检测。
Cosmology with High-redshift Galaxy Survey Neutrino Mass and Inflation
a r X i v :a s t r o -p h /0512374v 3 5 J u n 2006Cosmology with High-redshift Galaxy Survey:Neutrino Mass and InflationMasahiro Takada 1,Eiichiro Komatsu 2and Toshifumi Futamase 11Astronomical Institute,Tohoku University,Sendai 980-8578,Japan and 2Department of Astronomy,The University of Texas at Austin,Austin,TX 78712High-z galaxy redshift surveys open up exciting possibilities for precision determinations of neu-trino masses and inflationary models.The high-z surveys are more useful for cosmology than low-z ones owing to much weaker non-linearities in matter clustering,redshift-space distortion and galaxy bias,which allows us to use the galaxy power spectrum down to the smaller spatial scales that are inaccessible by low-z surveys.We can then utilize the two-dimensional information of the linear power spectrum in angular and redshift space to measure the scale-dependent suppression of matter clustering due to neutrino free-streaming as well as the shape of the primordial power spectrum.To illustrate capabilities of high-z surveys for constraining neutrino masses and the primordial power spectrum,we compare three future redshift surveys covering 300square degrees at 0.5<z <2,2<z <4,and 3.5<z <6.5.We find that,combined with the cosmic microwave background data expected from the Planck satellite,these surveys allow precision determination of the total neutrino mass with the projected errors of σ(m ν,tot )=0.059,0.043,and 0.025eV,respectively,thus yielding a positive detection of the neutrino mass rather than an upper limit,as σ(m ν,tot )is smaller than the lower limits to the neutrino masses implied from the neutrino oscillation experiments,by up to a factor of 4for the highest redshift survey.The accuracies of constraining the tilt and running index of the primordial power spectrum,σ(n s )=(3.8,3.7,3.0)×10−3and σ(αs )=(5.9,5.7,2.4)×10−3at k 0=0.05Mpc −1,respectively,are smaller than the current uncertainties by more than an or-der of magnitude,which will allow us to discriminate between candidate inflationary models.In particular,the error on αs from the future highest redshift survey is not very far away from the prediction of a class of simple inflationary models driven by a massive scalar field with self-coupling,αs =−(0.8−1.2)×10−3.PACS numbers:95.55.Vj,98.65.Dx,98.80.Cq,98.70.Vc,98.80.EsI.INTRODUCTIONWe are living in the golden age of cosmology.Vari-ous data sets from precision measurements of tempera-ture and polarization anisotropy in the cosmic microwave background (CMB)radiation as well as those of matter density fluctuations in the large-scale structure of the universe mapped by galaxy redshift surveys,Lyman-αforests and weak gravitational lensing observations are in a spectacular agreement with the concordance ΛCDM model [1,2,3,4].These results assure that theory of cos-mological linear perturbations is basically correct,and can accurately describe the evolution of photons,neu-trinos,baryons,and collisionless dark matter particles [5,6,7],for given initial perturbations generated during inflation [8,9].The predictions from linear perturbation theory can be compared with the precision cosmological measurements,in order to derive stringent constraints on the various basic cosmological parameters.Future obser-vations with better sensitivity and higher precision will continue to further improve our understanding of the uni-verse.Fluctuations in different cosmic fluids (dark matter,photons,baryons,and neutrinos)imprint characteristic features in their power spectra,owing to their interac-tion properties,thermal history,equation of state,and speed of sound.A remarkable example is the acoustic oscillation in the photon-baryon fluid that was generated before the decoupling epoch of photons,z ≃1088,which has been observed in the power spectrum of CMB tem-perature anisotropy [10],temperature–polarization cross correlation [11],and distribution of galaxies [12,13].Yet,the latest observations have shown convincingly that we still do not understand much of the universe.The standard model of cosmology tells us that the universe has been dominated by four components.In chronolog-ical order the four components are:early dark energy (also known as “inflaton”fields),radiation,dark mat-ter,and late-time dark energy.The striking fact is that we do not understand the precise nature of three (dark matter,and early and late-time dark energy)out of the four components;thus,understanding the nature of these three dark components has been and will continue to be one of the most important topics in cosmology in next decades.Of which,one might be hopeful that the next generation particle accelerators such as the Large Hadron Collider (coming on-line in 2007)would find some hints for the nature of dark matter particles.On the other hand,the nature of late-time dark energy,which was dis-covered by measurements of luminosity distance out to distant Type Ia supernovae [14,15],is a complete mys-tery,and many people have been trying to find a way to constrain properties of dark energy (see,e.g.,[16]for a review).How about the early dark energy,inflaton fields,which caused the expansion of the universe to accelerate in the very early universe?We know little about the nature of inflaton,just like we know little about the nature of late-time dark energy.The required property of infla-ton fields is basically the same as that of the late-time2dark energy component:both must have a large negativepressure which is less than−1/3of their energy density. To proceed further,however,one needs more informationfrom observations.Different inflation models make spe-cific predictions for the shape of the power spectrum[8](see also Appendix B)as well as for other statistical prop-erties[17]of primordial perturbations.Therefore,one ofthe most promising ways to constrain the physics of in-flation,hence the nature of early dark energy in the uni-verse,is to determine the shape of the primordial power spectrum accurately from observations.For example,theCMB data from the Wilkinson Microwave Anisotropy Probe[1],combined with the large-scale structure datafrom the Two-Degree Field Galaxy Redshift Survey[18], have already ruled out one of the popular inflationarymodels driven by a self-interacting massless scalarfield [19].Understanding the physics of inflation better willlikely provide an important implication for late-time dark energy.“Radiation”in the universe at around the matter-radiation equality mainly consists of photons and neu-trinos;however,neutrinos actually stop being radiationwhen their mean energy per particle roughly equals the temperature of the universe.The physics of neutrinoshas been revolutionized over the last decade by solar, atmospheric,reactor,and accelerator neutrino experi-ments having provided strong evidence forfinite neutrino masses via mixing between different neutrinoflavors,theso-called neutrino oscillations[20,21,22,23,24].These experiments are,however,only sensitive to mass squaredifferences between neutrino mass eigenstates,implying ∆m221≃7×10−5eV2and∆m232≃3×10−3eV2;thus, the most fundamental quantity of neutrinos,the abso-lute mass,has not been determined yet.Cosmologicalneutrinos that are the relic of the cosmic thermal his-tory have distinct influences on the structure formation.Their large energy density,comparable to the energy den-sity of photons before the matter-radiation equality,de-termines the expansion history of the universe.Even after the matter-radiation equality,neutrinos having be-come non-relativistic affect the structure formation by suppressing the growth of matter densityfluctuations at small spatial scales owing to their large velocity disper-sion[25,26,27,28,29,30](see Sec.II and Appendix A for more details).Therefore,the galaxy redshift surveys, combined with the CMB data,provide a powerful,albeit indirect,means to constraining the neutrino properties [31,32,33,34,35].This approach also complements the theoretical and direct experimental efforts for under-standing the neutrino physics.In fact,the cosmological constraints have placed the most stringent upper bound on the total neutrino mass,mν,tot<∼0.6eV(2σ)[36], stronger than the direct experiment limit<∼2eV[37].In addition,the result obtained from the Liquid Scintillator Neutrino Detector(LSND)experiment,which implies¯νµto¯νe oscillations with∆m2>∼0.2eV2[38]in an apparent contradiction with the other neutrino oscillation experi-ments mentioned above,potentially suggests the need for new physics:the cosmological observations will provide independent tests of this hypothesis.In this paper we shall study the capability of future galaxy surveys at high redshifts,combined with the CMB data,for constraining(1)the neutrino properties,more specifically the total neutrino mass,mν,tot,and the num-ber of non-relativistic neutrino species,N nrν,and(2)the shape of the primordial power spectrum that is parame-terized in terms of the spectral tilt,n s,and the running index,αs,motivated by inflationary predictions(see Ap-pendix B).For the former,we shall pay particular at-tention to our ability to simultaneously constrain mν,tot and N nrν,as they will provide important clues to resolv-ing the absolute mass scale as well as the neutrino mass hierarchy.The accuracy of determining the neutrino pa-rameters and the power spectrum shape parameters will be derived using the Fisher information matrix formal-ism,including marginalization over the other cosmologi-cal parameters as well as the galaxy bias.Our analysis differs from the previous work on the neutrino parameters in that we fully take into account the two-dimensional nature of the galaxy power spec-trum in the line-of-sight and transverse directions,while the previous work used only spherically averaged,one-dimensional power spectra.The geometrical distortion due to cosmology and the redshift space distortion due to the peculiar velocityfield will cause anisotropic features in the galaxy power spectrum.These features help to lift degeneracies between cosmological parameters,sub-stantially reducing the uncertainties in the parameter de-terminations.This is especially true when variations in parameters of interest cause modifications in the power spectrum shape,which is indeed the case for the neutrino parameters,tilt and running index.The usefulness of the two-dimensional power spectrum,especially for high-redshift galaxy surveys,has been carefully investigated in the context of the prospected constraints on late-time dark energy properties[39,40,41,42,43,44,45].We shall show the parameter forecasts for future wide-field galaxy surveys that are already being planned or seriously under consideration:the Fiber Multiple Object Spectrograph(FMOS)on Subaru telescope[46],its sig-nificantly expanded version,WFMOS[47],the Hobby–Ebery Telescope Dark Energy eXperiment(HETDEX) [48],and the Cosmic Inflation Probe(CIP)mission[49]. To model these surveys,we consider three hypothetical galaxy surveys which probe the universe over different ranges of redshift,(1)0.5≤z≤2,(2)2≤z≤4and (3)3.5≤z≤6.5.Wefix the sky coverage of each sur-vey atΩs=300deg2in order to make a fair compari-son between different survey designs.As we shall show below,high-redshift surveys are extremely powerful for precision cosmology because they allow us to probe the linear power spectrum down to smaller length scales than surveys at low redshifts,protecting the cosmological in-formation against systematics due to non-linear pertur-bations.We shall also study how the parameter uncertainties3 are affected by changes in the number density of sam-pled galaxies and the survey volume.The results wouldgive us a good guidance to defining the optimal surveydesign to achieve the desired accuracies in parameter de-terminations.The structure of this paper is as follows.In Sec.II,wereview the physical pictures as to how the non-relativistic(massive)neutrinos lead to scale-dependent modifica-tions in the growth of mass clustering relative to thepure CDM model.Sec.III defines the parameterization of the primordial power spectrum motivated by inflation-ary predictions.In Sec.IV we describe a methodology to model the galaxy power spectrum observable from aredshift survey that includes the two-dimensional nature in the line-of-sight and transverse directions.We thenpresent the Fisher information matrix formalism that is used to estimate the projected uncertainties in the cos-mological parameter determination from statistical errors on the galaxy power spectrum measurement for a givensurvey.After survey parameters are defined in Sec.V, we show the parameter forecasts in Sec.VI.Finally,wepresent conclusions and some discussions in Sec.VII.We review the basic properties of cosmological neutrinos inAppendix A,the basic predictions from inflationary mod-els for the shape of the primordial power spectrum in Ap-pendix B,and the relation between the primordial powerspectrum and the observed power spectrum of matter densityfluctuations in Appendix C.In the following,we assume an adiabatic,cold dark matter(CDM)dominated cosmological model withflatgeometry,which is supported by the WMAP results [1,36],and employ the the notation used in[51,52]:the present-day density of CDM,baryons,and non-relativistic neutrinos,in units of the critical density,aredenoted asΩc,Ωb,andΩν,respectively.The total mat-ter density is thenΩm=Ωc+Ωb+Ων,and fνis theratio of the massive neutrino density contribution toΩm: fν=Ων/Ωm.II.NEUTRINO EFFECT ON STRUCTUREFORMATIONThroughout this paper we assume the standard ther-mal history in the early universe:there are three neutrinospecies with temperature equal to(4/11)1/3of the photon temperature.We then assume that0≤N nrν≤3species are massive and could become non-relativistic by thepresent epoch,and those non-relativistic neutrinos have equal masses,mν.As we show in Appendix A,the den-sity parameter of the non-relativistic neutrinos is given byΩνh2=N nrνmν/(94.1eV),where we have assumed 2.725K for the CMB temperature today[50],and h is the Hubble parameter defined as H0=100h km s−1Mpc−1. The neutrino mass fraction is thus given byfν≡Ων0.658eV 0.141eVΩm h21+z 1/2.(2)Therefore,non-relativistic neutrinos with lighter masses suppress the growth of structure formation on larger spa-tial scales at a given redshift,and the free-streaming length becomes shorter at a lower redshift as neutrino velocity decreases with redshift.The most important property of the free-streaming scale is that it depends on the mass of each species,mν,rather than the total mass,N nrνmν;thus,measurements of k fs allow us to dis-tinguish different neutrino mass hierarchy models.For-tunately,k fs appears on the scales that are accessible by galaxy surveys:k fs=0.096−0.179Mpc−1at z=6−1 for mν=1eV.On the spatial scales larger than the free-streaming length,k<k fs,neutrinos can cluster and fall into gravi-tational potential well together with CDM and baryonic matter.In this case,perturbations in all matter com-ponents(CDM,baryon and neutrinos,denoted as‘cbν’hereafter)grow at the same rate given byD cbν(k,z)∝D(z)k≪k fs(z),(3) where D(z)is the usual linear growth factor(see,e.g., Eq.(4)in[53]).On the other hand,on the scales smaller than the free-streaming length,k>k fs,perturbations in non-relativistic neutrinos are absent due to the large ve-locity dispersion.In this case,the gravitational potential well is supported only by CDM and baryonic matter,and the growth of matter perturbations is slowed down rela-tive to that on the larger scales.As a result,the matter power spectrum for k>k fs is suppressed relative to that for k<k fs.In this limit the total matter perturbations grow at the slower rate given byD cbν(k,z)∝(1−fν)[D(z)]1−p k≫k fs(z),(4) where p≡(5−√4FIG.1:Suppression in the growth rate of total matter per-turbations(CDM,baryons and non-relativistic neutrinos), D cbν(a),due to neutrino free-streaming.(a=(1+z)−1is the scale factor.)Upper panel:D cbν(a)/Dν=0(a)for the neutrino mass fraction of fν=Ων/Ωm=0.05.The number of non-relativistic neutrino species is varied from N nrν=1,2,and3 (from thick to thin lines),respectively.The solid,dashed,and dotted lines represent k=0.01,0.1,and1h Mpc−1,respec-tively.Lower panel:D cbν(a)/Dν=0(a)for a smaller neutrino mass fraction,fν=0.01.Note that the total mass of non-relativistic neutrinos isfixed to mν,tot=N nrνmν=0.66eV and0.13eV in the upper and lower panels,respectively. Eq.(2).It is thus expected that a galaxy survey with different redshift slices can be used to efficiently extract the neutrino parameters,N nrνand mν.The upper and middle panels of Figure2illustrate how free-streaming of non-relativistic neutrinos suppresses the amplitude of linear matter power spectrum,P(k), at z=4.Note that we have normalized the primordial power spectrum such that all the power spectra match at k→0(see§III).To illuminate the dependence of P(k) on mν,wefix the total mass of non-relativistic neutri-nos,N nrνmν,by fν=0.05and0.01in the upper and middle panels,respectively,and vary the number of non-relativistic neutrino species as N nrν=1,2and3.The suppression of power is clearly seen as one goes from k<k fs(z)to k>k fs(z)(see Eq.[2]for the value of k fs).The way the power is suppressed may be easily un-derstood by the dependence of k fs(z)on mν;for example,linear power spectrum at z=4due to free-streaming of non-relativistic neutrinos.Wefix the total mass of non-relativistic neutrinos by fν=Ων/Ωm=0.05,and vary the number of non-relativistic neutrino species(which have equal masses, mν)as N nrν=1(solid),2(dashed),and3(dot-dashed). The mass of individual neutrino species therefore varies as mν=0.66,0.33,and0.22eV,respectively(see Eq.[1]).The shaded regions represent the1-σmeasurement errors on P(k) in each k-bin,expected from a galaxy redshift survey observ-ing galaxies at3.5≤z≤4.5(see Table I for definition of the survey).Note that the errors are for the spherically averaged power spectrum over the shell of k in each bin.Different N nrνcould be discriminated in this case.Middle panel:Same as in the upper panel,but for a smaller neutrino mass fraction, fν=0.01.While it is not possible to discriminate between different N nrν,the overall suppression on small scales is clearly seen.Lower panel:Dependences of the shape of P(k)on the other cosmological parameters.P(k)at smaller k is more suppressed for a smaller mν,as lighter neutrinos have longer free-streaming lengths.Onvery small scales,k≫k fs(z)(k>∼1and0.1Mpc−1for fν=0.05and0.01,respectively),however,the amountof suppression becomes nearly independent of k,and de-pends only on fν(or the total neutrino mass,N nrνmν) as∆P5 ≈8fν.(5)We therefore conclude that one can extract fνand N nrνseparately from the shape of P(k),if the suppression “pattern”in different regimes of k is accurately measured from observations.5Are observations good enough?The shaded boxes in the upper and middle panels in Figure2represent the1-σmeasurement errors on P(k)expected from one of the fiducial galaxy surveys outlined in Sec.V.Wefind thatP(k)will be measured with∼1%accuracy in each k bin. If other cosmological parameters were perfectly known,the total mass of non-relativistic neutrinos as small as mν,tot=N nrνmν>∼0.001eV would be detected at more than2-σ.This limit is much smaller than the lower mass limit implied from the neutrino oscillation exper-iments,0.06eV.This estimate is,of course,unrealistic because a combination of other cosmological parameters could mimic the N nrνor fνdependence of P(k).The lower panel in Figure2illustrates how other cosmolog-ical parameters change the shape of P(k).In the fol-lowing,we shall extensively study how well future high-redshift galaxy surveys,combined with the cosmic mi-crowave background data,can determine the mass of non-relativistic neutrinos and discriminate between different N nrν,fully taking into account degeneracies between cos-mological parameters.III.SHAPE OF PRIMORDIAL POWER SPECTRUM AND INFLATIONARY MODELSInflation generally predicts that the primordial power spectrum of curvature perturbations is nearly scale-invariant.Different inflationary models make specific predictions for deviations of the primordial spectrum from a scale-invariant spectrum,and the deviation is of-ten parameterized by the“tilt”,n s,and the“running index”,αs,of the primordial power spectrum.As the pri-mordial power spectrum is nearly scale-invariant,|n s−1| and|αs|are predicted to be much less than unity. This,however,does not mean that the observed mat-ter power spectrum is also nearly scale-invariant.In Ap-pendix C,we derive the power spectrum of total matter perturbations that is normalized by the primordial cur-vature perturbation(see Eq.[C6])k3P(k,z)5H20Ωm 2×D2cbν(k,z)T2(k) k2αs ln(k/k0),(6)where k0=0.05Mpc−1,δ2R=2.95×10−9A,and A is the normalization parameter given by the WMAP collaboration[1].We adopt A=0.871,which gives δR=5.07×10−5.(In the notation of[63,64]δR=δζ.) The linear transfer function,T(k),describes the evolu-tion of the matter power spectrum during radiation era and the interaction between photons and baryons be-fore the decoupling of photons.Note that T(k)depends only on non-inflationary parameters such asΩm h2and Ωb/Ωm,and is independent of n s andαs.Also,the effects of non-relativistic neutrinos are captured in D cbν(k,z); thus,T(k)is independent of time after the decoupling epoch.We use thefitting function found in[51,52]for T(k).Note that the transfer function and the growth rate are normalized such that T(k)→1and D cbν/a→1 as k→0during the matter era.In Appendix B we describe generic predictions on n s andαs from inflationary models.For example,inflation driven by a massive,self-interacting scalarfield predicts n s=0.94−0.96andαs=(0.8−1.2)×10−3for the num-ber of e-foldings of expansion factor before the end of inflation of50.This example shows that precision deter-mination of n s andαs allows us to discriminate between candidate inflationary models(see[8]for more details). IV.MODELING GALAXY POWER SPECTRUMA.Geometrical and Redshift-Space DistortionSuppose now that we have a redshift survey of galax-ies at some redshift.Galaxies are biased tracers of the underlying gravitationalfield,and the galaxy power spec-trum measures how clustering strength of galaxies varies as a function of3-dimensional wavenumbers,k(or the inverse of3-dimensional length scales).We do not measure the length scale directly in real space;rather,we measure(1)angular positions of galax-ies on the sky,and(2)radial positions of galaxies in redshift space.To convert(1)and(2)to positions in 3-dimensional space,however,one needs to assume a ref-erence cosmological model,which might be different from the true cosmology.An incorrect mapping of observed angular and redshift positions to3-dimensional positions produces a distortion in the measured power spectrum, known as the“geometrical distortion”[54,55,56].The geometrical distortion can be described as follows.The comoving size of an object at redshift z in radial,r ,and transverse,r⊥,directions are computed from the exten-sion in redshift,∆z,and the angular size,∆θ,respec-tively,asr =∆zH(z′),(8) where H(z)is the Hubble parameter given byH2(z)=H20 Ωm(1+z)3+ΩΛ .(9)6 HereΩm+ΩΛ=1,andΩΛ≡Λ/(3H20)is the present-daydensity parameter of a cosmological constant,Λ.A trickypart is that H(z)and D A(z)in Eq.(7)depend on cosmo-logical models.It is therefore necessary to assume somefiducial cosmological model to compute the conversionfactors.In the following,quantities in thefiducial cos-mological model are distinguished by the subscript‘fid’.Then,the length scales in Fourier space in radial,kfid ,and transverse,kfid⊥,directions are estimated from theinverse of rfid and rfid⊥.Thesefiducial wavenumbers arerelated to the true wavenumbers byk⊥=D A(z)fidH(z)fidkfid .(10)Therefore,any difference between thefiducial cosmolog-ical model and the true model would cause anisotropicdistortions in the estimated power spectrum in(kfid⊥,kfid )space.In addition,shifts in z due to peculiar velocities ofgalaxies distort the shape of the power spectrum alongthe line-of-sight direction,which is known as the“redshiftspace distortion”[57].From azimuthal symmetry aroundthe line-of-sight direction,which is valid when a distant-observer approximation holds,the linear power spectrumestimated in redshift space,P s(kfid⊥,kfid ),is modeled in[39]asP s(kfid⊥,kfid )=D A(z)2fid H(z)k2⊥+k22×b21P(k,z),(11)where k=(k2⊥+k2)1/2andβ(k,z)≡−1d ln(1+z),(12)is a function characterizing the linear redshift space distortion,and b1is a scale-independent,linear biasparameter.Note thatβ(k,z)depends on both red-shift and wavenumber via the linear growth rate.Inthe infall regime,k≪k fs(z),we have b1β(k,z)≈−d ln D(z)/d ln(1+z),while in the free-streaming regime, k≫k fs(z),we have b1β(k,z)≈−(1−p)d ln D(z)/d ln(1+ z),where p is defined below Eq.(4).One might think that the geometrical and redshift-space distortion effects are somewhat degenerate in the measured power spectrum.This would be true only if the power spectrum was a simple power law.For-tunately,characteristic,non-power-law features in P(k) such as the broad peak from the matter-radiation equal-ity,scale-dependent suppression of power due to baryons and non-relativistic neutrinos,the tilt and running of the primordial power spectrum,the baryonic acoustic os-cillations,etc.,help break degeneracies quite efficiently [39,40,41,42,43,44,47,55,56].ments on Baryonic OscillationsIn this paper,we employ the linear transfer function with baryonic oscillations smoothed out(but includes non-relativistic neutrinos)[51,52].As extensively in-vestigated in[39,44,47],the baryonic oscillations can be used as a standard ruler,thereby allowing one to precisely constrain H(z)and D A(z)separately through the geo-metrical distortion effects(especially for a high-redshift survey).Therefore,our ignoring the baryonic oscillations might underestimate the true capability of redshift sur-veys for constraining cosmological parameters.We have found that the constraints on n s andαs from galaxy surveys improve by a factor of2–3when baryonic oscillations are included.This is because the baryonic os-cillations basicallyfix the values ofΩm,Ωm h2andΩb h2, lifting parameter degeneracies betweenΩm h2,Ωb h2,n s, andαs.However,we suspect that this is a rather opti-mistic forecast,as we are assuming aflat universe dom-inated by a cosmological constant.This might be a too strong prior,and relaxing our assumptions about geom-etry of the universe or the properties of dark energy will likely result in different forecasts for n s andαs.In this paper we try to separate the issues of non-flat universe and/or equation of state of dark energy from the physics of neutrinos and inflation.We do not include the bary-onic oscillations in our analysis,in order to avoid too optimistic conclusions about the constraints on the neu-trino parameters,n s,andαs.Eventually,the full analysis including non-flat uni-verse,arbitrary dark energy equation of state and its time dependence,non-relativistic neutrinos,n s,andαs, using all the information we have at hand including the baryonic oscillations,will be necessary.We leave it for a future publication(Takada and Komatsu,in prepara-tion).C.Parameter Forecast:Fisher Matrix Analysis In order to investigate how well one can constrain the cosmological parameters for a given redshift survey de-sign,one needs to specify measurement uncertainties of the galaxy power spectrum.When non-linearity is weak, it is reasonable to assume that observed density perturba-tions obey Gaussian statistics.In this case,there are two sources of statistical errors on a power spectrum measure-ment:the sampling variance(due to the limited number of independent wavenumbers sampled from afinite sur-vey volume)and the shot noise(due to the imperfect sampling offluctuations by thefinite number of galax-ies).To be more specific,the statistical error is given in [58,59]by∆P s(k i)N k 1+1。
Neutrino Mass Hierarchy, Vacuum Oscillations, and Vanishing U_e3
(m3)
2
(m2) (m1)
2
2
(∆m )12
2
(∆m2)23
νe νµ ντ (∆m )13
2
(∆m )12
2
(m2)2 (m1)
2
(m3)
2
FIG. 1: Two distinct neutrino-mass hierarchies that fit all of the current neutrino data, from [1]. The color coding (shading) indicates the fraction |Uαi |2 of each distinct flavor να , α = e, µ, τ contained in each mass eigenstate νi , i = 1, 2, 3. For example, |Ue2 |2 is equal to the fraction of the (m2 )2 “ห้องสมุดไป่ตู้ar” that is painted red (shading labeled as ‘νe ’).
∗
We adopt the “standard” definition of neutrino mass eigenstates (discussed below) and the lepton mixing matrix U [3].
2
normal hierarchy
inverted hierarchy
2 2 modulo terms proportional to ∆m2 12 or |Ue3 |. These are suppressed because ∆m12 ≪ |∆m13 | (at the three sigma 2 2 2 level, ∆m12 /|∆m13 | < 0.06 [6]), which we know from solar and KamLAND data, and |Ue3 | ≪ 1 (at the three sigma level, |Ue3 |2 < 0.051 [6]), which we know from reactor and atmospheric data. Current experiments are not sensitive to these sub-leading terms, and it is clear that Eq. (I.1) is only sensitive to |∆m2 13 |. Hence both a normal and an inverted mass hierarchy fit the data equally well. In this paper, we explore several different oscillation probes of the neutrino mass hierarchy, and discuss under what conditions these can be experimentally accessible. More specifically, we concentrate our efforts on probes other than “matter-affected 13 oscillations,” which have been heavily explored in the literature and are defined and very briefly discussed in Sec. II. To date, all phenomenological studies of how to determine the neutrino mass hierarchy via neutrino oscillations have, to the best of our knowledge, relied on a non-zero value for |Ue3 |, and almost all appeal to matter effects in the 13 sector. One of the goals of this paper is to argue that neither matter effects nor a nonzero value of |Ue3 | are required in order to determine the neutrino mass hierarchy via neutrino oscillations — at least in principle. There are many reasons for pursuing novel oscillation probes of the neutrino mass hierarchy. One is that we would, ultimately, like to compare distinct determinations of the mass hierarchy. Such a comparison provides a test of whether there is new physics in the lepton sector besides three flavor oscillations. Another (and, perhaps, the most important) reason for pursuing different hierarchy-exploring channels is that, if θ13 turns out to be too small, the traditional approach will not work, so new experimental probes are not only desirable but absolutely necessary! Our presentation is the following. In Sec. II, we briefly review how the mass hierarchy can be revealed if |Ue3 | is large enough and there are nontrivial matter effects at work. In Sec. III, we remind readers that even in the case of pure vacuum oscillations the mass hierarchy is, in principle, observable. We then review one realistic method for determining the mass hierarchy using only vacuum disappearance channels. In Sec. IV, we study in detail the case θ13 = 0, and discuss various approaches one might consider in this case to determine the mass hierarchy. In Sec. V, we summarize our results and offer some concluding thoughts. A technical presentation of the oscillation probabilities in constant matter for vanishing θ13 is included as an appendix. Our approach is “theoretical,” in the sense that we study the behavior of oscillation probabilities as a function of
Search for neutrino oscillations on a long base-line at the CHOOZ nuclear power station
2 δm2 = m2 2 − m1 as follows:
P (ν e → ν e ) = 1 − sin2 2θ sin2
1.27 δm2(eV2 ) L(m) Eν (MeV)
.
(1) Atmospheric neutrino results give a δm2 from 10−2 to 10−3 eV2 . Long base-line (L-B) reactor neutrino experiments [15] have been one of the most powerful ways to investigate ν e → ν µ neutrino oscillations (or, more generally, ν e → ν x oscillations). The CHOOZ [16,17] and PALO VERDE[18] experiments utilized the high intensity and purity of the reactor core flux to achieve high sensitivity. The CHOOZ experiment had an average value of L/E ∼ 300 (L ∼ 1 km, E ∼ 3 MeV), an intense and nearly pure neutrino flavour composition (∼ 100% ν e ) and an intensity known to better than 2%. It could therefore make a definitive contribution to solving the problem of the atmospheric neutrino anomaly. CHOOZ removed the possibility of explaining the atmospheric neutrino anomaly by νe ↔ νµ oscillations and Super–Kamiokande showed that νµ ↔ ντ caused the effect [19]. The experiment was designed to detect reactor ν e ’s via the inverse β -decay reaction ν e + p → e+ + n (2)
抵消抽烟的危害英语作文
Smoking is widely recognized as a detrimental habit that poses numerous health risks.However,for those who are unable to quit,there are several strategies that can be implemented to mitigate the harmful effects of smoking.Here are some ways to offset the damage caused by smoking:1.Maintain a Healthy Diet:Eating a balanced diet rich in fruits,vegetables,whole grains, and lean proteins can help to counteract some of the negative impacts of smoking. Antioxidants found in these foods can help to neutralize free radicals produced by tobacco smoke.2.Regular Exercise:Engaging in regular physical activity can strengthen the cardiovascular system,which is often compromised by smoking.Exercise also helps to improve lung function and overall health.3.Hydration:Drinking plenty of water helps to flush out toxins from the body and keeps the respiratory system hydrated,which can be beneficial for smokers.4.Quit Gradually:If quitting cold turkey is too difficult,consider gradually reducing the number of cigarettes smoked each day.This can help to lessen the withdrawal symptoms and make the transition to a smokefree life easier.5.Nicotine Replacement Therapy NRT:Using NRT such as nicotine gum,patches,or lozenges can help to satisfy nicotine cravings without the harmful chemicals found in cigarettes.6.Avoid Secondhand Smoke:Minimize exposure to secondhand smoke by avoiding places where smoking is allowed and by not allowing others to smoke around you.7.Supplements:Certain supplements,such as vitamin C and E,can help to boost the immune system and reduce oxidative stress caused by smoking.8.Regular Medical Checkups:Regular health checkups can help to detect any early signs of smokingrelated diseases and ensure timely treatment.9.Stress Management:Since many people smoke as a way to cope with stress,learning stress management techniques such as meditation,yoga,or deep breathing exercises can help to reduce the need to smoke.10.Support Groups:Joining a support group or seeking counseling can provide emotional support and practical advice on how to deal with the challenges of smokingcessation.11.Limit Alcohol Consumption:Alcohol can lower inhibitions and make it more difficult to resist the urge to smoke,so limiting alcohol intake can be beneficial.cate Yourself:Understanding the risks associated with smoking can motivate individuals to take steps towards a healthier lifestyle.While these strategies can help to reduce the harm caused by smoking,the best way to eliminate these risks is to quit smoking altogether.Its never too late to quit,and doing so will significantly improve ones health and quality of life.。
GMAT阅读练习（10）
Passage 1 Virtually everything astronomers known about objects outside the solar system is based on the detection of photons-quanta of electromagnetic radiation. Yet there is another form of radiation that permeates the universe： （5） neutrinos. With （as its name implies） no electric charge， and negligible mass， the neutrino interacts with other particles so rarely that a neutrino can cross the entire universe， even traversing substantial aggregations of matter， without being absorbed or even deflected. Neu- （10） trinos can thus escape from regions of space where light and other kinds of electromagnetic radiation are blocked by matter. Furthermore， neutrinos carry with them information about the site and circumstances of their production： therefore， the detection of cosmic neutrinos （15） could provide new information about a wide variety of cosmic phenomena and about the history of the uni- verse. But how can scientists detect a particle that interacts so infrequently with other matter？ Twenty-five years （20） passed between Pauli's hypothesis that the neutrino existed and its actual detection： since then virtually all research with neutrinos has been with neutrinos created artificially in large particle accelerators and studied under neutrino microscopes. But a neutrino telescope， （25） capable of detecting cosmic neutrinos， is difficult to co- nstruct. No apparatus can detect neutrinos unless it is extremely massive， because great mass is synonymous with huge numbers of nucleons （neutrons and protons）， and the more massive the detector， the greater the pro- （30） bability of one of its nucleon's reacting with a neutrino. In addition， the apparatus must be sufficiently shielded from the interfering effects of other particles. Fortunately， a group of astrophysicists has proposed a means of detecting cosmic neutrinos by harnessing the （35） mass of the ocean. Named DUMAND， for Deep Under- water Muon and Neutrino Detector， the project calls for placing an array of light sensors at a depth of five kilo- meters under the ocean surface. The detecting medium is the seawater itself： when a neutrino interacts with a （40） particle in an atom of seawater， the result is a cascade of electrically charged particles and a flash of light that can be detected by the sensors. The five kilometers of sea- water above the sensors will shield them from the interf- ering effects of other high-energy particles raining down （45） through the atmosphere. The strongest motivation for the DUMAND project is that it will exploit an important source of information about the universe. The extension of astronomy from visible light to radio waves to x-rays and gamma rays （50） never failed to lead to the discovery of unusual objects such as radio galaxies， quasars， and pulsars. Each of these discoveries came as a surprise. Neutrino astronomy will doubtless bring its own share of surprises. 1. Which of the following titles best summarizes the passage as a whole？ （A） At the Threshold of Neutrino Astronomy （B） Neutrinos and the History of the Universe （C） The Creation and Study of Neutrinos （D） The DUMAND System and How It Works （E） The Properties of the Neutrino 2. With which of the following statements regarding neutrino astronomy would the author be most likely to agree？ （A） Neutrino astronomy will supersede all present forms of astronomy. （B） Neutrino astronomy will be abandoned if the DUMAND project fails. （C） Neutrino astronomy can be expected to lead to major breakthroughs in astronomy. （D） Neutrino astronomy will disclose phenomena that will be more surprising than past discoveries. （E） Neutrino astronomy will always be characterized by a large time lag between hypothesis and experimental confirmation. 3. In the last paragraph， the author describes the development of astronomy in order to （A） suggest that the potential findings of neutrino astronomy can be seen as part of a series of astronomical successes （B） illustrate the role of surprise in scientific discovery （C） demonstrate the effectiveness of the DUMAND apparatus in detecting neutrinos （D） name some cosmic phenomena that neutrino astronomy will illuminate （E） contrast the motivation of earlier astronomers with that of the astrophysicists working on the DUMAND project 4. According to the passage， one advantage that neutrinos have for studies in astronomy is that they （A） have been detected for the last twenty-five years （B） possess a variable electric charge （C） are usually extremely massive （D） carry information about their history with them （E） are very similar to other electromagnetic particles 5. According to the passage， the primary use of the apparatus mentioned in lines 24-32 would be to （A） increase the mass of a neutrino （B） interpret the information neutrinos carry with them （C） study the internal structure of a neutrino （D） see neutrinos in distant regions of space （E） detect the presence of cosmic neutrinos 6. The passage states that interactions between neutrinos and other matter are （A） rare （B） artificial （C） undetectable （D） unpredictable （E） hazardous 7. The passage mentions which of the following as a reason that neutrinos are hard to detect？ （A） Their pervasiveness in the universe （B） Their ability to escape from different regions of space （C） Their inability to penetrate dense matter （D） The similarity of their structure to that of nucleons （E） The infrequency of their interaction with other matter 8. According to the passage， the interaction of a neutrino with other matter can produce （A） particles that are neutral and massive （B） a form of radiation that permeates the universe （C） inaccurate information about the site and circumstances of the neutrino's production （D） charged particles and light （E） a situation in which light and other forms of electromagnetic radiation are blocked 9. According to the passage， one of the methods used to establish the properties of neutrinos was （A） detection of photons （B） observation of the interaction of neutrinos with gamma rays （C） observation of neutrinos that were artificially created （D） measurement of neutrinos that interacted with particles of seawater （E） experiments with electromagnetic radiation Passage 2 Since the late 1970's， in the face of a severe loss of market share in dozens of industries， manufacturers in the United States have been trying to improve produc- tivity-and therefore enhance their international （5） competitiveness-through cost-cutting programs. （Cost- cutting here is defined as raising labor output while holding the amount of labor constant.） However， from 1978 through 1982， productivity-the value of goods manufactured divided by the amount of labor input- （10） did not improve； and while the results were better in the business upturn of the three years following， they ran 25 percent lower than productivity improvements during earlier， post-1945 upturns. At the same time， it became clear that the harder manufacturers worked to imple- （15） ment cost-cutting， the more they lost their competitive edge. With this paradox in mind， I recently visited 25 companies； it became clear to me that the cost-cutting approach to increasing productivity is fundamentally （20） flawed. Manufacturing regularly observes a “40， 40， 20” rule. Roughly 40 percent of any manufacturing-based competitive advantage derives from long-term changes in manufacturing structure （decisions about the number， size， location， and capacity of facilities） and in approaches （25） to materials. Another 40 percent comes from major changes in equipment and process technology. The final 20 percent rests on implementing conventional cost- cutting. This rule does not imply that cost-cutting should not be tried. The well-known tools of this approach- （30） including simplifying jobs and retraining employees to work smarter， not harder-do produce results. But the tools quickly reach the limits of what they can contribute. Another problem is that the cost-cutting approach （35） hinders innovation and discourages creative people. As Abernathy's study of automobile manufacturers has shown， an industry can easily become prisoner of its own investments in cost-cutting techniques， reducing its ability to develop new products. And managers under （40） pressure to maximize cost-cutting will resist innovation because they know that more fundamental changes in processes or systems will wreak havoc with the results o n / p > p b d s f i d = " 2 1 7 " > 0 0 w h i c h t h e y a r e m e a s u r e d . P r o d u c t i o n m a n a g e r s h a v e / p > p b d s f i d = " 2 1 8 " > 0 0 a l w a y s s e e n t h e i r j o b a s o n e o f m i n i m i z i n g c o s t s a n d / p >。
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Now named (at this meeting) the Abdus Salam International Centre for Theoretical Physics.
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role in the growth of the ideas which we initiated. Let me touch upon one aspect of Salam’s personality. During the ten year period of our collaboration, there have been many letters, faxes, arguments over the phone and in person and even heated exchanges, about tastes and judgements in physics, but always in a good natured spirit
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Based in part on a talk delivered at the Abdus Salam Memorial Meeting, ICTP, Trieste, November 1997.
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I. Salam in Perspective
Abdus Salam was a great scientist and a humanitarian. His death was indeed a loss to science and especially to the growth of science in the third world. He will surely be remembered for his contributions to physics, some of which have proven to be of lasting value. These include his pioneering work on electroweak unification for which he shared the Nobel Prize in physics in 1979 with Sheldon Glashow and Steven Weinberg. Contribution of this calibre is rare. But I believe his most valuable contribution to science and humanity, one that is perhaps unparalleled in the world, is the sacrifice he has made of his time, energy and personal comfort in promoting the cause of science in different corners of the globe, in particular the third world. His lifelong efforts in this direction have led to the creation of some outstanding research centres, including especially the International Centre for Theoretical Physics (ICTP) at Trieste, Italy,
UMD-PP99-052
WITH NEUTRINO MASSES REVEALED, PROTON
arXiv:hep-ph/98114来自2v1 23 Nov 1998
DECAY IS THE MISSING LINK
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Jogesh C. Pati Physics Department, University of Maryland, College Park, MD 20742, USA October, 1998
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In our discussions, Salam
had some favorite phrases. For example, he would sometimes come up with an idea and get excited. If I expressed that I did not like it for such and such reason, he would get impatient and say to me: ”My dear sir, what do you want: Blood?” I would sometimes reply by saying: ”No Professor Salam, I would like something better”. Whether I was right or wrong, he never took it ill. It is this attitude on his part that led to a healthy collaboration and a strong bond between us. Most important for me, by providing strong encouragement from the beginning, yet often arguing, he could bring out the best in a collaborator. For this I will remain grateful to him. By way of paying tribute to Salam therefore, I would first like to recall briefly the ideas on higher unification which we initiated (Sec. 2), and then present their current status in the context of subsequent experimental and theoretical developments (Secs. 3,4, and 5). The experiments of special relevance are: (a) recent observation of neutrino oscillation at SuperKamiokande, (b) the precision measurements of the gauge couplings at LEP, and (c) ongoing searches for proton decay. In Section 3, I discuss how the recent discovery of atmospheric neutrino-oscillation at SuperKamiokande 4 , especially the mass of ντ suggested by the SuperK result, on the one hand agrees well with the gauge coupling unification revealed by the extrapolation of the LEP data, and on the other hand provides clear support for the route to higher unification based on the concepts of SU(4)-color and left-right symmetry. On the theoretical side, the major developments of the last two decades are the ideas of supersymmetry, superstrings, and now M-theory. I will briefly remark how these later developments fully retain the basic ideas of higher unification of the 70’s, and at the same time, provide a substantially new
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an International Centre for Genetic Engineering and Biotech-
nology with components in Trieste and Delhi, and an International Centre for Science and High Technology in Trieste. Salam dreamed of creating twenty international centres like the ICTP, spread throughout the world, emphasizing different areas of science and technology. Approaching developed as well as developing nations, for funding of such institutions, Salam often used the phrase: ”science is not cheap, but expenditures on it will repay tenfold” [1]. If only Salam had lived a few more years in good health, many more such institutions would have surely come to fruition. Salam was also a strong supporter of world peace, and thus of nuclear disarmament and Pugwash. Thus, in addition to his numerous awards for his contributions to physics, including the Nobel prize, he also received, some major awards for his contributions to peace and international collaboration, including the Atoms for Peace Award in 1968 and the ”Ettore Majorana” - Science for Peace prize in 1989. It is hard to believe that a single individual can accomplish so much in one lifetime. In this sense, Salam was indeed a rare individual—a phenomenon. I was especially fortunate to have collaborated with Salam closely for over a decade. Of this period, I treasure most the memory of many moments which were marked by the struggle and the joy of research that we both shared. Needless to say, Salam played a central