See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/243388338 Gauge Theory of Elementary Particle Physics Article in Physics Today · December 1985 DOI: 10.1063/1.2814821 CITATIONS READS 1,018 21,487 3 authors, including: Ta-Pei Cheng Ling-Fong Li University of Missouri - St. Louis Chinese Academy of Sciences 106 PUBLICATIONS 5,224 CITATIONS 89 PUBLICATIONS 5,271 CITATIONS SEE PROFILE SEE PROFILE Some of the authors of this publication are also working on these related projects: Resource Letter: GI1 Gauge invariance View project Einstein's Physics View project All content following this page was uploaded by Ta-Pei Cheng on 20 January 2014. The user has requested enhancement of the downloaded file. Gauge theory of elementary particle physics Problems and solutions TA-PEI CHENG University of Missouri - St. Louis and LING-FONG LI Carnegie Mellon University CLARENDON PRESS 2000 • OXFORD Contents 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 1.10 1.11 1.12 1.13 1.14 Field quantization _ Simple exercises in X(j>4 theory Auxiliary field Disconnected diagrams Simple external field problem Path integral for a free particle Path integral for a general quadratic action Spreading of a wave packet Path integral for a harmonic oscillator Path integral for a partition function Partition function for an SHO system Non-standard path-integral representation Weyl ordering of operators Generating functional for a scalar Poles in Green's function 1 field 6 8 9 11 13 16 17 21 23 25 26 32 35 2 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 Renormalization Counterterms in Xtp4 theory and in QED Divergences in non-linear chiral theory Divergences in lower-dimensional field theories n-Dimensional 'spherical' coordinates Some integrals in dimensional regularization Vacuum polarization and subtraction schemes Renormalization of X<p3 theory in n dimensions Renormalization of composite operators Cutkosky rules 37 39 41 43 46 49 53 57 59 3 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 Renormalization group Homogeneous renormalization-group equation Renormalization constants /3-function for QED Behaviour of g near a simple fixed point Running coupling near a general fixed point One-loop renormalization-group equation in massless \<f>A theory ^-function for the Yukawa coupling t Solving the renormalization-group equation by Coleman's method Anomalous dimensions for composite operators 63 64 67 69 70 71 72 75 77 viii l Contents 4 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10 4.11 4.12 4.13 4.14 4.15 4.16 Group theory and the quark model Unitary and hermitian matrices SU(n) matrices Reality of SU(2) representations An identity for unitary matrices An identity for SU(2) matrices SU(3) algebra in terms of quark fields Combining two spin-^ states The SU(2) adjoint representation Couplings of SU(2) vector representations Isospin breaking effects Spin wave function of three quarks Permutation symmetry in the spin-isospin space Combining two fundamental representations SU(3) invariant octet baryon-meson couplings Isospin wave functions of two pions Isospins in non-leptonic weak processes 78 79 79 81 82 83 85 87 89 90 93 96 97 100 105 107 5 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 5.10 Chiral symmetry Another derivation of Noether's current Lagrangian with second derivatives Conservation laws in a non-relativistic theory Symmetries of the linear a-model Spontaneous symmetry breaking in the a-model PCAC in the a-model Non-linear cr-model I Non-linear a-model II Non-linear a -model HI SSB by two scalars in the vector representation 110 111 113 115 122 123 126 128 130 133 6 6.1 6.2 6.3 6.4 Renormalization and symmetry Path-integral derivation of axial anomaly Axial anomaly and r\ -*• yy Soft symmetry breaking and renormalizability Calculation of the one-loop effective potential 136 140 142 143 7 7.1 7.2 7.3 7.4 7.5 The Parton model and scaling The Gottfried sum rule Calculation of OPE Wilson coefficients otot(e+e~ —*• hadrons) and short-distance physics OPE of two charged weak currents The total decay rate of the W-boson / 146 147 151 155 156 8 8.1 8.2 8.3 Gauge symmetries The gauge field in tensor notation Gauge field and geometry General relativity as a gauge theory 158 161 163 Contents ix 8.4 8.5 8.6 8.7 8.8 8.9 O(n) gauge theory Broken generators and Goldstone bosons Symmetry breaking by an adjoint scalar Symmetry breaking and the coset space Scalar potential and first-order phase transition Superconductivity as a Higgs phenomenon 165 167 169 171 172 173 9 9.1 9.2 9.3 9.4 9.5 9.6 9.7 9.8 Quantum gauge theories Propagator in the covariant R^ gauge The propagator for a massive vector Gauge boson propagator in the axial gauge Gauge boson propagator in the Coulomb gauge Gauge invariance of a scattering amplitude Ward identities in QED Nilpotent BRST charges BRST charges and physical states 10 10.1 10.2 10.3 10.4 10.5 Quantum chromodynamics Colour factors in QCD loops Running gauge coupling in two-loop Cross-section for three-jet events Operator-product expansion of two currents Calculating Wilson coefficients 188 191 193 198 201 11 11.1 11.2 11.3 11.4 11.5 11.6 11.7 11.8 Electroweak theory Chiral spinors and helicity states The polarization vector for a fermion The pion decay rate and fn Uniqueness of the standard model scalar potential Electromagnetic and gauge couplings Fermion mass-matrix diagonalization An example of calculable mixing angles Conservation of the B — L quantum number 205 206 208 212 213 214 215 216 12 12.1 12.2 12.3 12.4 12.5 12.6 12.7 12.8 12.9 Electroweak phenomenology Atomic parity violation Polarization asymmetry of Z - » / / Simple r-lepton decays Electron neutrino scatterings CP properties of kaon non-leptonic decays Z - • HH is forbidden A/ — \ enhancement by short-distance QCD Scalar interactions and the equivalence theorem Two-body decays of a heavy Higgs boson 218 221 222 223 225 226 227 230 234 field 175 176 177 178 180 180 184 186 x Contents 13 13.1 13.2 13.3 13.4 13.5 13.6 Topics in flavourdynamics Anomaly-free condition in a technicolour theory Pseudo-Goldstone bosons in a technicolour model Properties of Majorana fermions fj, —> ey and heavy neutrinos Leptonic mixings in a vector-like theory Muonium-antimuonium transition 238 239 239 244 250 252 14 14.1 14.2 14.3 14.4 14.5 14.6 14.7 14.8 Grand unification Content of SU(5) representations Higgs potential for SU(5) adjoint scalars Massive gauge bosons in SU(5) Baryon number non-conserving operators SO(n) group algebra Spinor representations of SO(«) Relation between SO(2«) and SU(n) groups Construction of SO(2n) spinors 255 256 258 260 260 263 267 269 15 15.1 15.2 15.3 15.4 Magnetic monopoles The Sine-Gordon equation Planar vortex Stability of soliton Monopole and angular momentum 275 280 282 283 16 16.1 16.2 16.3 Instantons The saddle-point method An application of the saddle-point method A Euclidean double-well problem field 289 292 295 References 301 Index 303 View publication