 | Particle physics in the LHC era / G.Barr, R.Devenish, R.Walczak, T.Weidberg. - Oxford: Oxford University Press, 2016. - xviii, 403 p.: ill. - (Oxford master series in particle physics, astrophysics, and cosmology). - Bibliogr.: p.391-397. - Ind.: p.399-403. - ISBN 978-0-19-874856-4
Шифр: (И/В38-Р29) 02
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1 Introduction ............................................... 1
1.1 Units ...................................................... 2
1.2 Early days ................................................. 2
1.2.1 Particles and forces ................................ 3
1.2.2 Group theory in particle physics .................... 4
1.2.3 Particles ........................................... 5
1.2.4 Forces .............................................. 6
1.3 Diagrams ................................................... 7
1.4 Accelerators, colhders, and detectors ...................... 8
1.4.1 Accelerators ........................................ 8
1.4.2 Colliders .......................................... 10
1.5 Detectors ................................................. 10
1.6 Open questions ............................................ 11
1.7 Chapter outline ........................................... 12
1.8 How to read this book ..................................... 13
Chapter summary ........................................... 13
Further reading ........................................... 14
2 Mathematical methods ...................................... 15
2.1 Discrete symmetries ....................................... 15
2.1.1 Spatial parity ..................................... 15
2.1.2 Charge conjugation ................................. 16
2.1.3 Time reversal ...................................... 17
2.1.4 JPC of hadrons ..................................... 18
2.1.5 Useful examples .................................... 18
2.2 Addition of angular momentum .............................. 19
2.2.1 Angular momentum in quantum mechanics .............. 19
2.2.2 Addition and Clebsch-Gordan coefficients ........... 21
2.2.3 Calculation of Clebsch-Gordan coefficients ......... 21
2.3 Spatial rotations ......................................... 23
2.4 Lorentz invariance ........................................ 29
2.4.1 Invariant variables ................................ 30
2.4.2 Rapidity ........................................... 30
2.5 Transitions and observables ............................... 31
2.5.1 Phase space and decay rates ........................ 32
2.5.2 Decay rate ......................................... 34
2.5.3 Cross section ...................................... 39
2.5.4 Breit-Wigner ....................................... 40
2.5.1 Luminosity and event rates ......................... 42
2.7 Group theory .............................................. 43
2.7.1 Lie groups ......................................... 44
2.7.2 U(n) and SU(n) ..................................... 44
2.7.3 SU(2) .............................................. 45
2.7.4 Combining states ................................... 46
Chapter summary ........................................... 46
Further reading ........................................... 46
Exercises ................................................. 47
3 Accelerators .............................................. 48
3.1 Radiofrequency acceleration ............................... 48
3.1.1 Electric and magnetic fields ....................... 48
3.1.2 Circular accelerators and synchronicity ............ 49
3.1.3 Accelerating-cavity design and Q factor ............ 51
3.1.4 Synchrotron radiation energy loss .................. 53
3.1.5 Linear accelerators ................................ 53
3.1.6 Klystrons .......................................... 54
3.2 Beam optics ............................................... 54
3.2.1 Magnetic lenses .................................... 54
3.2.2 Beam trajectories and phase space .................. 57
3.3 LHC dipole magnets ........................................ 59
3.3.1 Engineering design details ......................... 61
3.4 Colliders and fixed-target accelerators ................... 62
3.5 Luminosity ................................................ 63
3.6 pp cohiders ............................................... 65
3.6.1 CERN pp collider ................................... 66
3.6.2 Tevatron pp colhder ................................ 67
3.7 Future accelerators ....................................... 67
Chapter summary ........................................... 68
Further reading ........................................... 68
Exercises ................................................. 69
4 Particle detectors ........................................ 71
4.1 Introduction .............................................. 71
4.2 Overview of collider detectors ............................ 72
4.3 Particle interactions with matter ......................... 74
4.3.1 Ionization ......................................... 74
4.3.2 Multiple scattering ................................ 76
4.3.3 Electromagnetic interactions ....................... 77
4.3.4 Cerenkov radiation ................................. 79
4.3.5 Transition radiation ............................... 79
4.3.6 Hadronic interactions .............................. 79
4.4 Signal generation ......................................... 81
4.4.1 Moving charges ..................................... 81
4.4.2 Scintillators ...................................... 84
4.5 Photon detection .......................................... 85
4.6 Detectors for charged-particle tracks ..................... 86
4.6.1 Wire chambers ...................................... 87
4.6.2 Silicon detectors .................................. 92
4.6.3 Tracker performance ................................ 97
4.7 Detectors for particle jets ............................... 98
4.7.1 Electromagnetic calorimeter ........................ 98
4.7.2 Homogeneous calorimeters ........................... 99
4.7.3 Sandwich calorimeters ............................. 100
4.7.4 Resolution ........................................ 102
4.7.5 Hadronic calorimeter .............................. 103
4.8 Detectors for particle identification .................... 105
4.8.1 Particle identification with Cerenkov detection ... 105
4.8.2 Particle identification with transition
radiation ......................................... 105
4.8.3 Particle identification with ionization ........... 106
4.9 Magnetic fields .......................................... 106
4.9.1 Magnetic fields for trackers ...................... 106
4.9.2 Magnetic fields for muon spectrometers ............ 107
4.10 Trigger .................................................. 108
4.10.1 LHC triggers ...................................... 109
4.11 Examples of detector systems ............................. 109
4.11.1 Collider detectors ................................ 109
4.11.2 Neutrino detectors ................................ 111
Chapter summary .......................................... 112
Further reading .......................................... 112
Exercises ................................................ 112
5 Static quark model ....................................... 115
5.1 Spin 1/2 ................................................. 115
5.1.1 Combining two spin-1/2 particles .................. 116
5.1.2 Combining three spin-1/2 particles ................ 117
5.2 The quark model of hadrons ............................... 118
5.2.1 Isospin ........................................... 119
5.2.2 Strangeness and expansion to SU(3) ................ 122
5.2.3 Mesons ............................................ 123
5.2.4 Baryons ........................................... 125
5.2.5 Deriving the complete spin-flavour wavefunction ... 127
5.3 Heavy quarks ............................................. 128
5.3.1 The charm quark ................................... 129
5.3.2 The beauty quark .................................. 130
5.3.3 The top quark ..................................... 130
5.3.4 Charm and beauty states ........................... 130
5.3.5 Heavy QQ systems .................................. 132
5.3.6 Charmonium ........................................ 132
5.3.7 Comparison with positronium ....................... 134
5.3.8 Bottomonium ....................................... 136
5.4 Exotic hadrons ........................................... 137
Chapter summary .......................................... 138
Further reading .......................................... 138
Exercises ................................................ 139
6 Relativistic quantum mechanics ........................... 140
6.1 Special relativity ....................................... 140
6.1.1 Spinors ........................................... 142
6.2 One-particle states ...................................... 147
6.2.1 Fields and probability amplitudes ................ 148
6.3 The Klein-Gordon equation ................................ 149
6.3.1 The Feynman-Stueckelberg interpretation of
negative-energy states ............................ 151
6.4 The Dirac equation ....................................... 155
6.4.1 Free-particle solutions ........................... 159
6.4.2 Chirality ≠ helicity .............................. 161
6.4.3 Helicity conservation and interactions via
currents .......................................... 163
6.4.4 P, T, and a comment on С .......................... 166
6.4.5 Electromagnetic interactions and the
non-relativistic limit ............................ 169
6.5 Gauge symmetry ........................................... 172
6.5.1 Covariant derivative .............................. 172
6.5.2 Gauge invariance in electromagnetism .............. 174
6.5.3 The Aharonov-Bohm effect .......................... 174
6.5.4 Interactions from gauge symmetry .................. 175
Chapter summary .......................................... 178
Further reading .......................................... 178
Exercises ................................................ 179
7 Weak interactions ........................................ 181
7.1 Fermi theory ............................................. 182
7.2 Weak interactions of leptons ............................. 183
7.2.1 Lepton number ..................................... 183
7.2.2 Feynman rules ..................................... 183
7.2.3 Universality ...................................... 185
7.2.4 V-A ............................................... 186
7.2.5 Parity violation .................................. 187
7.2.6 Currents and fields ............................... 187
7.3 Weak interactions including quarks ....................... 189
7.3.1 Cabibbo theory .................................... 189
7.3.2 GIM mechanism, flavour-changing neutral currents .. 189
7.3.3 CKM matrix ........................................ 190
7.3.4 Decays of hadrons containing heavy quarks ......... 192
7.4 Introduction to electroweak unification .................. 193
7.4.1 Electroweak unification procedure ................. 193
7.4.2 Weak neutral currents ............................. 199
7.4.3 Masses of W and Z bosons .......................... 200
7.4.4 The standard model, how good is it? ............... 201
Chapter summary .......................................... 202
Further reading .......................................... 203
Exercises ................................................ 203
8 Experimental tests of electroweak theory ................. 205
8.1 Neutrinos ................................................ 205
8.2 Charged currents ......................................... 206
8.2.1 Measurements of CKM matrix elements ............... 207
8.3 Neutral currents ......................................... 208
8.4 Physics at e+e- colliders ................................ 208
8.4.1 Detailed look at the detectors .................... 209
8.4.2 Aspects of a physics analysis ..................... 213
8.4.3 Monte Carlo simulation ............................ 213
8.4.4 Physics at LEP .................................... 215
8.4.5 The Z line shape .................................. 216
8.4.6 Z mass ............................................ 217
8.4.7 The Z width; number of neutrinos .................. 217
8.4.8 LEP beam energy measurement ....................... 218
8.4.9 Cross sections and forward-backward asymmetries
at the Z .......................................... 219
8.4.10 LEP luminosity measurement ........................ 221
8.4.11 Measurements at LEP2, above √s = Mz ............... 221
8.4.12 Ж" production ..................................... 222
8.4.13 σ(e+e- → W+W-) ..................................... 223
8.5 W and Z physics at hadron colliders ...................... 224
8.5.1 W and Z discovery ................................. 224
8.5.2 W mass determination at the Tevatron .............. 225
8.5.3 Width of the W .................................... 228
8.6 Top-quark physics ........................................ 229
8.6.1 Top-quark discovery ............................... 229
8.6.2 Top-quark mass measurement ........................ 230
8.6.3 Top-quark production cross sections ............... 231
8.7 Summary .................................................. 232
Chapter summary .......................................... 233
Further reading .......................................... 233
Exercises ................................................ 233
9 Dynamic quarks ........................................... 235
9.1 Rutherford scattering .................................... 235
9.2 Scattering from nucleons ................................. 239
9.3 Quark-parton model ....................................... 240
9.3.1 Kinematics of deep inelastic scattering .......... 240
9.4 Neutrino interactions .................................... 242
9.4.1 Cross section for neutrino-electron elastic
scattering ........................................ 243
9.4.2 Neutrino-quark scattering ......................... 245
9.4.3 Neutrino-nucleon cross sections ................... 246
9.4.4 Parton distribution functions ..................... 247
9.5 Charged-lepton probes .................................... 251
9.5.1 Electron-muon elastic scattering .................. 252
9.5.2 Electron-quark elastic scattering ................. 254
9.5.3 Electron-nucleon deep inelastic scattering ........ 254
9.5.4 Further tests of the QPM .......................... 2
9.5.5 Electroweak unification at HERA ................... 258
9.6 QCD introduction ......................................... 259
9.6.1 Direct evidence for gluons ........................ 260
9.6.2 Number of colours ................................. 261
9.6.3 QCD ............................................... 262
9.6.4 Running couphng constants ......................... 266
9.6.5 Experimental tests of the gauge structure of QCD .. 269
9.6.6 Experimental fits to the quark distribution
functions ......................................... 271
9.6.7 The gluon distribution function ................... 271
9.7 Hadron hadron collisions ................................. 272
9.7.1 Drell-Yan ......................................... 273
Chapter summary .......................................... 274
Further reading .......................................... 275
Exercises ................................................ 275
10 Oscillations and CP violation in meson systems ........... 277
10.1 Symmetries ............................................... 278
10.2 Neutral kaon decays and K1 and К2 ........................ 278
10.3 Mass differences of neutral mesons ....................... 281
10.4 Flavour oscillations ..................................... 282
10.4.1 K0-K0 oscillations ................................ 283
10.4.2 D0-D0 oscillations ................................ 284
10.4.3 B0-B0 mixing and oscillations ..................... 285
10.4.4 Bs oscillations ................................... 287
10.4.5 Regeneration ...................................... 288
10.5 CP violation (part 1) .................................... 289
10.5.1 Discovery of CP violation ......................... 289
10.5.2 Semileptonic charge asymmetry ..................... 291
10.5.3 CP violation in K0 decay .......................... 292
10.6 CP violation in the Standard Model ....................... 294
10.6.1 Mixing with CP violation .......................... 296
10.7 CP violation (part 2) .................................... 297
10.7.1 CP violation in time-dependent asymmetries ........ 297
10.7.2 B-factories ....................................... 299
10.7.3 LHCb detector ..................................... 301
10.8 LHCb measurements ........................................ 302
Chapter summary .......................................... 304
Further reading .......................................... 304
Exercises ................................................ 304
11 Neutrino oscillations .................................... 306
11.1 Introduction ............................................. 306
11.1.1 Neutrino masses ................................... 306
11.2 Neutrino states .......................................... 307
11.3 Two-flavour oscillations ................................. 308
11.4 Evidence for neutrino oscillations ....................... 310
11.4.1 Atmospheric neutrinos ............................. 311
11.4.2 Laboratory confirmation of atmospheric neutrino
oscillation ....................................... 314
11.4.3 Solar neutrinos ................................... 315
11.4.4 MSW effect ........................................ 320
11.5 Three (or more)-flavour oscillations ..................... 323
11.5.1 Generahzed oscillation probabilities .............. 323
11.5.2 Three-flavour oscillations ........................ 326
11.5.3 Measurement of the mixing angle θ13 ............... 328
11.5.4 Matter-antimatter asymmetry ....................... 329
Chapter summary .......................................... 331
Further reading .......................................... 331
Exercises ................................................ 331
12 The Higgs boson .......................................... 333
12.1 Local gauge invariance ................................... 334
12.2 Spontaneous symmetry breaking ............................ 334
12.3 Higgs mechanism—the simplified story ..................... 336
12.4 Lagrangians .............................................. 337
12.4.1 Lagrangians in classical mechanics ................ 337
12.4.2 Lagrangians in quantum mechanics .................. 339
12.5 Higgs mechanism—more mathematical ........................ 339
12.6 Higgs discovery .......................................... 342
12.6.1 γγ channel ........................................ 344
12.6.2 ZZ* channel ....................................... 345
12.6.3 WW* channel ....................................... 346
12.6.4 Statistical significance .......................... 347
12.7 Couphng to fermions ...................................... 349
12.8 Determination of the spin and parity of the new boson .... 351
12.9 Outlook .................................................. 353
Chapter summary .......................................... 353
Further reading .......................................... 354
Exercises ................................................ 354
13 LHC and BSM .............................................. 356
13.1 LHC and Standard Model physics ........................... 356
13.2 LHC triggers ............................................. 358
13.3 SM measurements at the LHC ............................... 359
13.3.1 Top-quark production .............................. 365
13.4 Beyond the Standard Model physics ........................ 367
13.4.1 Supersymmetry ..................................... 368
13.4.2 R-parity .......................................... 371
13.4.3 Other BSM theories ................................ 372
13.5 Experimental searches for BSM physics at the LHC ......... 373
13.5.1 Jet production .................................... 373
13.5.2 Lepton pair resonances ............................ 373
13.5.3 SUSY searches ..................................... 373
13.5.4 Summary of searches for new physics ............... 379
13.6 Linear colhder ........................................... 379
13.7 Dark matter .............................................. 381
13.7.1 Astrophysical evidence for dark matter ............ 382
13.7.2 Direct dark matter detection ...................... 383
13.7.3 Dark matter annihilation .......................... 385
13.8 Dark energy .............................................. 385
13.8.1 Theoretical implications .......................... 386
Chapter summary .......................................... 387
Further reading .......................................... 388
Exercises ................................................ 388
References .................................................... 391
Index ......................................................... 399
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