The Physics of the Z and W Bosons

Contents......Page 12
Preface......Page 8
1.1 Weak interactions in the original Fermi approach......Page 18
1.2 Weak interactions and the intermediate vector bosons......Page 23
1.3 The Higgs mechanism in the local SU(2) gauge symmetry case......Page 26
1.4.1 The SU(2)   U(1) description of electroweak interactions......Page 33
1.4.2 Gauge boson masses in the SU(2)L   U(1)YL scheme......Page 37
1.4.3 The (W;Z) mass relationship and the  0 parameter......Page 41
1.4.4 Electroweak uni cation and weak neutral currents......Page 43
1.4.5 Numerical prediction for the gauge boson masses in the Minimal Standard Model......Page 49
1.5 Z physics as a test of the MSM......Page 51
1.5.1 The Higgs scalar mass in the MSM......Page 54
1.5.2.1 Inclusion of strong interactions......Page 55
1.5.2.2 Masses of leptons and quarks......Page 57
1.5.2.3 Family replication......Page 59
1.5.3 Tests of the MSM at LEP1/SLC......Page 65
1.5.4 Universality of weak interactions and number of fermion families......Page 68
2. Z Physics at Tree Level......Page 74
2.1 Conventions, spinors and basic cross sections......Page 75
2.2 Chiral fermions and polarized cross sections in the one-photon exchange......Page 78
2.3 Interaction involving a Z boson......Page 83
2.4 Computation of Z partial widths......Page 86
2.5 Angular and polarization asymmetries......Page 88
2.6 Asymmetries in the vicinity of the Z pole......Page 91
3. Z Physics at One Loop for Final Leptonic States......Page 94
3.1.1 The theoretical description at tree level......Page 101
3.1.2 Renormalizability and gauge transformations in the MSM......Page 104
3.1.3 Treatment of formally divergent quantities in e+e......Page 110
3.1.4 The dimensional regularization method......Page 116
3.1.5 Definition of physical parameters: renormalization of mW;mZ......Page 120
3.1.6 Charge renormalization and de nition in the MSM......Page 126
3.1.7 The `running\' of  QED in the MSM......Page 143
3.2.1 Choice of the most convenient input parameters: definition of the physical GF......Page 149
3.2.2 Derivation of Sirlin\'s equation: introduction and definition of the fundamental parameter  r......Page 156
3.2.3 Calculation of  r(f): identification of four classes of physical effects......Page 160
3.2.4 Numerical estimate of   (m2 Z)(f)......Page 164
3.2.5.1 Numerical estimate of  1(0)......Page 169
3.2.5.2 Numerical estimate of  3(m2 Z)......Page 171
3.2.5.3 Numerical estimate of  2......Page 173
3.2.5.4 Calculation of the W mass......Page 174
3.3.1 Operative definition of the electroweak mixing angle: the longitudinal polarization asymmetry......Page 175
3.3.2 Calculation of sin2  W;eff at one loop: fermion pairs contributions to self-energies......Page 179
3.3.3 Relationship between sin2  (f) and mZ......Page 185
3.3.4 The Z leptonic width at one loop in the `fermion pairs\' approximation......Page 186
3.4 The complete expression of sin2  W;eff at one loop......Page 190
3.4.1 A gauge-invariant classi cation of one-loop effects......Page 193
3.4.2 Operative definition of sin2  W;eff : the leptonic asymmetries at the Z peak......Page 202
3.5.1 Complete expression of the Z leptonic width at one-loop......Page 205
3.5.2 The Z peak leptonic observables in terms of the  1,  3 parameters......Page 210
3.5.3 Dependence of the weak parameters  1,  3 on the Higgs mass......Page 214
3.5.4 The  2 parameter and the complete expression of the W mass......Page 216
4. Z Physics at One Loop for Final Hadronic States......Page 220
4.1 The r^ole of the Zb vertex in Z physics......Page 221
4.1.1 Calculation of the electroweak component of the Zb vertex......Page 222
4.1.2 Observable effects of the Zb vertex at the Z peak: the large mt limit......Page 233
4.1.3 Operative definition of the Zb vertex at the Z peak: the  bV parameter......Page 237
4.2.1 Strong interactions effects at the Z peak......Page 244
4.2.2 Higher order strong coupling contributions......Page 248
5.1 LEP......Page 254
5.2 SLC......Page 255
5.3 Tevatron......Page 256
5.4 Beyond LEP, SLC and Tevatron: next colliders......Page 258
5.5 Detectors......Page 259
6. The Z Lineshape......Page 268
6.1 Initial state radiation in e+e collision......Page 269
6.2 The reduced cross sections......Page 270
6.3 Luminosity......Page 272
6.4 Centre-of-mass energy calibration in e+e- collision......Page 275
6.5 Selection of hadronic and leptonic Z decays......Page 281
6.6 Measuring the Z lineshape parameters......Page 283
7. Z Decays to Heavy Quarks......Page 290
7.1 General properties of hadronic events at the Z......Page 291
7.2.1 Lepton tagging......Page 293
7.2.2 Lifetime tagging......Page 299
7.2.3 Reconstruction of charmed hadrons......Page 310
7.2.4 Event shape tagging......Page 314
7.2.5 Gluon splitting to heavy quarks......Page 315
7.3 Rb measurements......Page 316
7.3.1 The single/double tag method......Page 317
7.3.3 Rb results......Page 321
7.4.1 Single/double tag......Page 322
7.4.3 Lepton analyses......Page 323
7.4.4 Charm counting......Page 324
7.4.5 R0 c results......Page 325
8. Asymmetries at the Z pole......Page 326
8.1 Measurement of the left-right asymmetry (ALR)......Page 327
8.2 Measurement of the tau polarization in Z decays......Page 331
8.3 Forward-backward asymmetries......Page 339
8.3.1 Lepton forward-backward asymmetries......Page 343
8.3.2.1 Lepton tagging......Page 345
8.3.2.2 Inclusive measurements......Page 349
8.3.2.3 Measurement of the jet charge asymmetry using all avours......Page 351
8.3.2.4 D meson measurements at LEP......Page 352
8.3.2.5 Heavy quark asymmetries: combined results and QCD corrections......Page 353
8.3.2.6 HF asymmetries with polarized beams......Page 354
8.4.2 Extraction of the neutral current couplings......Page 356
9. Electroweak Measurements with W Bosons......Page 362
9.1 W mass measurement at hadron colliders......Page 363
9.2 W production in e+e- collision......Page 367
9.3 W mass measurement in e+e- colliders......Page 373
9.4 Triple gauge couplings......Page 379
9.4.1 The e+e-  W+W- angular analysis and the W polarization......Page 381
9.4.2 The effective TGC lagrangian and the couplings......Page 384
10.1 Top-quark properties......Page 388
10.2 Direct measurement of the top mass......Page 390
10.3 Electroweak constraints on the top mass......Page 396
11. The Search for the Higgs Boson and Tests of the Electroweak Interaction......Page 400
11.1 Search for the Higgs boson before LEP......Page 401
11.3 Searching the Higgs at LEP1......Page 403
11.4 Setting confidence levels......Page 405
11.5 Higgs searches at LEP2......Page 408
11.6 The Higgs mass from electroweak  fits......Page 410
11.7 Model independent analysis of electroweak data......Page 412
12. Conclusions and Perspectives......Page 420
Bibliography......Page 426
Index......Page 434