内容简介
《粒子物理学标准模型导论(第2版)》从介子和夸克的电磁作用和弱相互作用开始,讲到了夸克的强相互作用,内容层层深入。介绍标准模型的同时,作者非常注重选材的可进阶性,方便读者更深入的研读。
内页插图
目录
Preface to the second edition
Preface to the first edition
Notation
1 The particle physicists view of Nature
1.1 Introduction
1.2 The construction of the Standard Model
1.3 Leptons
1.4 Quarks and systems of quarks
1.5 Spectroscopy of systems of light quarks
1.6 More quarks
1.7 Quark colour
1.8 Electron scattering from nucleons
1.9 Particle accelerators
1.10 Units
2 Lorentz transformations
2.1 Rotations, boosts and proper Lorentz transformations
2.2 Scalars, contravariant and covariant four-vectors
2.3 Fields
2.4 The Levi-Civita tensor
2.5 Time reversal and space inversion
3 The Lagrangian formulation of mechanics
3.1 Hamiltons principle
3.2 Conservation of energy
3.3 Continuous systems
3.4 A Lorentz covariant field theory
3.5 The Klein-Gordon equation
3.6 The energy-momentum tensor
3.7 Complex scalar fields
4 Classical electromagnetism
4.1 Maxwells equations
4.2 A Lagrangian density for electromagnetism
4.3 Gauge transformations
4.4 Solutions of Maxwells equations
4.5 Space inversion
4.6 Charge conjugation
4.7 Intrinsic angular momentum of the photon
4.8 The energy density of the electromagnetic field
4.9 Massive vector fields
5 The Dirac equation and the Dirac field
5.1 The Dirac equation
5.2 Lorentz transformations and Lorentz invariance
5.3 The parity transformation
5.4 Spinors
5.5 The matrices
5.6 Making the Lagrangian density real
6 Free space solutions of the Dirac equation
6.1 A Dirac particle at rest
6.2 The intrinsic spin of a Dirac particle
6.3 Plane waves and helicity
6.4 Negative energy solutions
6.5 The energy and momentum of the Dirac field
6.6 Dirac and Majorana fields
6.7 The E ] ] m limit, neutrinos
7 Electrodynamics
7.1 Probability density and probability current
7.2 The Dirac equation with an electromagnetic field
7.3 Gauge transformations and symmetry
7.4 Charge conjugation
7.5 The electrodynamics of a charged scalar field
7.6 Particles at low energies and the Dirac magnetic moment
8 Quantising fields: QED
8.1 Boson and fermion field quantisation
8.2 Time dependence
8.3 Perturbation theory
8.4 Renornmalisation and renormalisable field theories
8.5 The magnetic moment of the electron
8.6 Quantisation in the Standard Model
9 The weak interaction: !ow energy phenomenology
9.1 Nuclear beta decay
9.2 Pion decay
9.3 Conservation of lepton number
9.4 Muon decay
9.5 The interactions of muon neutrinos with electrons
10 Symmetry breaking in model theories
10.1 Global symmetry breaking and Goldstone bosons
10.2 Local symmetry breaking and the Higgs boson
11 Massive gauge fields
11.1 SU(2) symmetry
11.2 The gauge fields
11.3 Breaking the SU(2) symmetry
11.4 Identification of the fields
12 The Weinberg——Salam electroweak theory for leptons
12.1 Lepton doublets and the Weinberg-Salam theory
12.2 Lepton coupling to the W
12.3 Lepton coupling to the Z
12.4 Conservation of lepton number and conservation of charge
12.5 CP symmetry
12.6 Mass terms in : an attempted generalisation
13 Experimental tests of the Weinberg——Salam theory
13.1 The search for the gauge bosons
13.2 The W bosons
13.3 The Z boson
13.4 The number of lepton families
13.5 The measurement of partial widths
13.6 Left-right production cross-section asymmetry and lepton decay symmetry of the Z boson
14 The electromagnetic and weak interactions of quarks
14.1 Construction of the Lagrangian density
14.2 Quark masses and the Kobayashi-Maskawa mixing matrix
14.3 The parameterisation of the KM matrix
14.4 CP symmetry and the KM matrix
14.5 The weak interaction in the low energy limit
15 The hadronic decays of the Z and W bosons
15.1 Hadronic decays of the Z
15.2 Asymmetry in quark production
15.3 Hadronic decays of the W
16 The theory of strong interactions: quantum chromodynamics
16.1 A local SU(3) gauge theory
16.2 Colour gauge transformations on baryons and mesons
16.3 Lattice QCD and asymptotic freedom
16.4 The quark-antiquark interaction at short distances
16.5 The conservation of quarks
16.6 Isospin symmetry
16.7 Chiral symmetry
17 Quantum chromodynamics: calculations
17.1 Lattice QCD and confinement
17.2 Lattice QCD and hadrons
17.3 Perturbative QCD and deep inelastic scattering
17.4 Perturbative QCD and e+e- collider physics
18 The Kobayashi-Maskawa matrix
18.1 Leptonic weak decays of hadrons
18.2 |Vud| and nuclear decay
18.3 More leptonic decays
18.4 CP symmetry violation in neutral kaon decays
18.5 B meson decays and B,B mixing
18.6 The CPTtheorem
……
精彩书摘
5、The Dirac equation and the Dirac field
The Standard Model is a quantum field theory.In Chapter 4 we discussed the classical electromagnetic field.The transition to a quantum field will be made in Chapter 8.In this chapter we begin our discussion of the Dirac equation,which was invented bv Dirac as an equation for the relativistic quantum wave function of a single electron.However,we shall regard the Dirac wave function as a field.Which will subsequently be quantised along with the electromagnetic field.The Dirace quationwillberegardedasafieldequation.Thetransitiontoaquantumfieldtheory
iS called second quantisation.The field。like the Dirac wave function.is complex.W_e shall show how the Dirac field transforms under a Lorentz transformation.And find a Lorentz invariant Lagrangian from which it may be derived.
On quantisation,the electromagnetic fields A(x),Fv(x)become space-and time.dependent 0perators.The expectation Values of these operators in the environ- ment described by the quantum states are the classical fields.The Dirac fields(x) alSO become space-and time.dependent operators on quantisation.However,there are no corresponding measurable classical fields.This di骶rence reflects the Pauli exclusion principle,which applies to fermions but not to bosons.In this chapter and in the following two chapters,the properties of the Dirac fields as operators are rarely invoked:for the most part the manipulations proceed as if the Dirac fields were ordinary complex functions,and the fields Can be thought of as single-particle Dirac wave functions.
5.1 The Dirac equation
Dirac invented his equation in seeking to make Schr6dingerS equation for an elec-tron compatible with special relativity.
前言/序言
In the eight years since the first edition, the Standard Model has not been seriously discredited as a description of particle physics in the energy region ([2 TeV) so far explored. The principal discovery in particle physics since the first edition is that neutrinos carry mass. In this new edition we have added chapters that extend the formalism of the Standard Model to include neutrino fields with mass, and we consider also the possibility that neutrinos are Majorana particles rather than Dirac particles.
The Large Hadron Collider (LHC) is now under construction at CERN. It is expected that, at the energies that will become available for experiments at the LHC (~20 TeV), the physics of the Higgs field will be elucidated, and we shall begin to see physics beyond the Standard Model. Data from the B factories will continue to accumulate and give greater understanding of CP violation. We are confident that interest in the Standard Model will be maintained for some time into the future.
Cambridge University Press have again been most helpful. We thank Miss V. K.Johnson for secretarial assistance. We are grateful to Professor Dr J. G. K6rner for his corrections to the first edition, and to Professor C. Davies for her helpful correspondence.
探寻物质最微小的构成,理解宇宙运行的基本法则 本书并非关于“粒子物理学标准模型导论(第2版)”这本书本身的介绍。它致力于为您展现粒子物理学标准模型的魅力与深度,带您踏上一段探寻宇宙最基本构成单元和支配它们相互作用之力的旅程。 我们生活在一个由无数粒子组成的宏观世界,从浩瀚的星系到我们身体里的细胞。然而,将目光聚焦到最微小的尺度,我们会发现,所有这一切的构成,都源于一群更为基础的粒子,以及它们之间遵循的精妙规律。粒子物理学标准模型,正是我们目前对这一微观世界最成功的理论框架。它像一本宇宙的“原子表”,为我们列出了构成物质的基本粒子,并描绘了四种基本力(引力除外)如何在这些粒子之间传递信息、引发相互作用。 构成物质的基石:费米子家族 标准模型将所有基本粒子分为两大类:费米子(构成物质的粒子)和玻色子(传递力的粒子)。在费米子家族中,我们首先会深入了解夸克。它们是构成质子和中子的基本单元,分为六种“味”(up, down, charm, strange, top, bottom)和三种“色”(red, green, blue)。正是这些不同“颜色”的夸克,通过被称为“强相互作用”的强大力量被束缚在一起,形成了我们熟悉的质子和中子。 除了夸克,费米子家族还包括轻子。最广为人知的轻子莫过于电子,它是构成原子外壳,决定物质化学性质的关键。但电子并非孤军奋战,它还有与其相关的电子中微子。轻子家族同样拥有六种成员,按照质量和相互作用的规律,分为电子及其电子中微子,μ介子及其μ中微子,以及τ轻子及其τ中微子。这些粒子在宇宙的演化和各种物理过程中扮演着至关重要的角色,尽管中微子由于其极低的相互作用截面,使得探测它们成为一项艰巨的挑战。 传递力的信使:玻色子家族 如果说费米子是构建宇宙的砖块,那么玻色子就是连接这些砖块,并驱动宇宙运动的“胶水”和“信使”。标准模型描述了三种基本力(强力、弱力和电磁力)的传递方式,每种力都有其对应的玻色子。 胶子是传递强相互作用的粒子。它们的特性使得夸克被紧密地束缚在质子和中子内部,即使在极高的能量下也很难将它们分离。我们无法单独观测到胶子,它们的存在完全由它们所传递的强力来体现。 光子是传递电磁相互作用的粒子。它是电磁波的量子,我们所见的阳光、无线电波、X射线等,都是光子的不同表现形式。光子的无处不在,使得电磁力成为我们在日常生活中最为熟悉的相互作用。 W和Z玻色子是传递弱相互作用的粒子。虽然名为“弱”,但弱相互作用在某些过程中却至关重要,例如太阳的能量产生,以及某些放射性衰变。W和Z玻色子具有质量,这使得它们在传递弱相互作用时,作用范围相对较短。 赋予质量的奥秘:希格斯玻色子 然而,标准模型在解释粒子质量的来源方面,曾经遇到一个重大的难题。为什么电子有质量,而光子却没有?如果所有基本粒子都没有质量,那么宇宙的结构将完全不同。直到希格斯机制的提出,才最终解决了这一谜团。 希格斯机制的核心在于存在一个遍布宇宙的希格斯场。基本粒子在穿越这个场时,会与场发生“相互作用”,这种相互作用的强弱程度,决定了粒子所获得的质量大小。希格斯粒子(或称希格斯玻色子),便是希格斯场的量子激发。它的发现,是粒子物理学领域的一项里程碑式的成就,为标准模型提供了坚实的实验支撑。 标准模型的成功与局限 标准模型凭借其卓越的解释能力,成功地描述了大量实验数据,并精确预测了许多粒子现象。从粒子加速器中的碰撞实验,到宇宙射线的研究,都为标准模型提供了有力的证据。它解释了原子为何稳定,化学反应为何发生,以及恒星为何能够发光发热。 尽管如此,标准模型并非终极理论。它仍然存在一些未解之谜和局限性。例如,标准模型并未包含引力,这使得它无法与广义相对论统一。此外,它也无法解释暗物质和暗能量的本质,这两者构成了宇宙的大部分质量和能量。中微子质量的问题,以及是否存在比标准模型粒子更为基础的构成单元,也仍然是科学家们探索的前沿。 踏上探索之路 本书将引导您逐步理解这些基本粒子的性质、它们之间的相互作用,以及构成我们宇宙的宏伟图景。我们将从介绍基本概念入手,逐步深入到各个粒子的家族,以及四种基本力的量子理论描述。您将了解到,粒子物理学标准模型不仅仅是抽象的数学公式,更是我们理解物质起源、宇宙演化以及自然界最深层奥秘的有力工具。 这是一场关于微观世界的壮丽探索,一次对宇宙基本规律的深刻洞察。准备好,跟随我们一起,揭开物质最深处的面纱,感受粒子物理学的无穷魅力。