On the Flavor Problem in Strongly Coupled Theories - THEP Mainz

More documents

Recommendations

Info

92 Chapter 3. Solving the Flavor Problem in Strongly Coupled Theories 2 sin Θ A 0,l A FB (LEP) l A l(SLD) lept eff 0 σhad 0 Rlep (Q MZ ΓZ ) FB 0,c A FB 0,b A FB G fitter SM -3 -2 -1 0 1 2 3 (O - Omeas) / σ fit meas May 12 0.2 0.1 -1.7 -1.1 -0.8 0.3 -1.8 -0.8 0.9 2.6 Δα (5) had A c A b 0 Rc 0 Rb 2 (M ) M Z W ΓW mc mb mt -3 -2 -1 0 1 2 3 (O - Omeas) / σ fit meas Figure 3.1: This is a list of electroweak precision observables published by the GFitter group [133]. A definition of the observables can be found in the original paper or for example in [132, Sec.3A]. The bars show the deviation of the measurements from the SM predictions in standard deviation. 3.1 Electroweak Precision Observables The main focus of this thesis is on flavor changing processes. It is nevertheless important to consider implications from flavor conserving observables, especially if they have direct impact on the later discussions. Electroweak precision tests are a measure of new physics contributions to flavor conserving four fermion scattering processes, including both propagator and vertex corrections. They are an important check for new physics models and a particularly hard one for strongly coupled theories. In this section the reasons for this and the implications for the Randall Sundrum model will be discussed. It is assumed that the reader is familiar with the list of electroweak observables compiled in Figure 3.1. A detailed explanation for each observable can for example be found in [132, Sec.3A]. Indicated by the bars are the degrees of compatibility of the experimental values with the SM predictions measured in standard deviations, the so-called pull. Historically, fits to these observables have been used to successfully predict the mass of the top quark before its direct observation [132, Sec.3A]. Likewise, a global fit to these data has been used to constrain the Higgs mass window before its discovery. However, since Higgs-induced loops lead to logarithmic corrections, e.g. ∼ ln mh/mZ, while quark loops induce quadratic corrections ∼ m2 t /m2 Z , the top mass was a rather precise prediction, whereas the Higgs mass bound from the latest fit -0.1 0.6 0.0 -2.3 -1.5 -1.2 0.2 -0.0 -0.0 0.3
T 0.6 0.4 0.2 0.0 �0.2 99 � CL 95 � CL 68 � CL Mkk �1 �3 TeV Mkk �3 �10 TeV � 3.1. Electroweak Precision Observables 93 �0.4 �0.4 �0.2 0.0 0.2 0.4 0.6 S �� L L U = 0 Figure 3.2: The plots show regions of 68%, 95% and 99% probability in the S − T plane. Shaded red (orange) are the accessible regions for MKK ∈ [1 − 3] TeV (MKK ∈ [3 − 10] TeV) for the minimal model (growing vertically towards large T ) and for the custodially protected model (the horizontal stripe). The black arrows point in the direction of growing volume L ∈ [5, 36]. [133], mh = 96 +31 −24GeV , (3.1) can only be considered a rough guide pointing towards a rather light Higgs. These global fits do not only constrain the masses of hypothetical SM particles, but also of new physics resonances which contribute through radiative corrections. Basically every light new resonance with an electroweak quantum number is supposed to show up as a discrepancy in Figure 3.1. Possible cancellations of these contributions could therefore still have explained why the Higgs would be heavier than allowed by the SM fit (3.1), until it was finally found at mh ≈ 126 GeV [134, 135]. This makes electroweak precision test an even more powerful tool to constrain new physics, because every possible cancellation must occur between the new resonances and should therefore be predicted by the model at hand. Oblique Parameters All observables in Figure 3.1 show very good agreement with the SM, which is synonym with no deviation at 3σ or more. Apart from couplings of the Z to bottom quarks,
Page 1 and 2:
On the Flavor Problem in Strongly C
Page 3 and 4:
UNIVERSITY OF MAINZ ABSTRACT THEORE
Page 5 and 6:
Contents Acknowledgements vii Prefa
Page 7:
Acknowledgements First and foremost
Page 10 and 11:
x One of the most fascinating insig
Page 12 and 13:
2 Chapter 1. Introduction: Problems
Page 14 and 15:
Page 16 and 17:
Page 18 and 19:
Page 20 and 21:
10 Chapter 1. Introduction: Problem
Page 22 and 23:
Page 24 and 25:
Page 26 and 27:
Page 28 and 29:
Page 30 and 31:
Page 32 and 33:
Page 34 and 35:
Page 36 and 37:
Page 38 and 39:
Page 40 and 41:
Page 42 and 43:
Page 44 and 45:
Page 46 and 47:
36 Chapter 2. The Randall Sundrum M
Page 48 and 49:
Page 50 and 51:
Page 52 and 53: 42 Chapter 2. The Randall Sundrum M
Page 104 and 105: 94 Chapter 3. Solving the Flavor Pr
Page 110 and 111: 100 Chapter 3. Solving the Flavor P
Page 152 and 153:
142 Chapter 3. Solving the Flavor P
Page 154 and 155:
144 Chapter 3. Solving the Flavor P
Page 156 and 157:
146 Chapter 4. The Asymmetry in Top
Page 158 and 159:
Page 160 and 161:
Page 162 and 163:
Page 164 and 165:
Page 166 and 167:
Page 168 and 169:
Page 170 and 171:
Page 172 and 173:
Page 174 and 175:
Page 176 and 177:
Page 178 and 179:
Page 180 and 181:
Page 182 and 183:
Page 184 and 185:
Page 186 and 187:
176 Chapter 5. Conclusions describe
Page 188 and 189:
178 Appendix A. Generating Paramete
Page 190 and 191:
180 Appendix A. Generating Paramete
Page 192 and 193:
182 Appendix B. Neutral Meson Mixin
Page 194 and 195:
184 Appendix B. Neutral Meson Mixin
Page 197 and 198:
C Input Parameters This appendix is
Page 199:
Parameter Value ± Error Reference
Page 202 and 203:
192 Appendix D. Higgs Potential for
Page 204 and 205:
194 Bibliography [13] S. Dimopoulos
Page 206 and 207:
196 Bibliography [43] G. Nordström
Page 208 and 209:
198 Bibliography [72] K. S. Babu,
Page 210 and 211:
200 Bibliography [104] R. Contino a
Page 212 and 213:
202 Bibliography [133] M. Baak, M.
Page 214 and 215:
204 Bibliography [160] J. Charles,
Page 216 and 217:
206 Bibliography [185] C. Csaki, G.
Page 218 and 219:
208 Bibliography [213] E. Thomson e
Page 220:
210 Bibliography [239] V. Ahrens, A
show all

On the Flavor Problem in Strongly Coupled Theories - THEP Mainz

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?