On the Flavor Problem in Strongly Coupled Theories - THEP Mainz

More documents

Recommendations

Info

176 Chapter 5. Conclusions described, which unfortunately implies a baroque Higgs sector in order to realize the Yukawa couplings on the IR brane, that does not lead to a predictive mass spectrum for the new scalar states due to the vast number of free parameters in the potential. The impact of the RS model with and without the extended color gauge group on flavor diagonal processes, namely electroweak precision observables, has also been studied in Chapter 3. It turns out that the recent updates on the fit to the Z → ¯bb pseudo observables put very severe constraints on the couplings of the Z or induces a large KK scale. Adopting a custodial protection in order to prevent this, which is also the best way to suppress large contribution to the oblique T parameter, however reintroduces a tension with the contributions from the resonances charged under the extended color gauge group to ɛK. If the flavor problem of the RS model is explained by the mechanism introduced in this thesis, this tension must be addressed by either a different suppression of contributions to the electroweak precision observables, or by a more inventive realization of the scalar sector. In this context it should be mentioned that during the completion of this thesis, a paper has been published, whose authors also find only a minor improvement for the custodial model with extended color gauge group [244]. The bound derived there comes from the loop induced direct CP violation in Kaon mixing measured by ɛ ′ /ɛK and is due to the exchange of the new scalar degrees of freedom and therefore also rooted in the extended Higgs sector. The last chapter focuses on the question of whether the question whether the observed forward-backward asymmetry at the Tevatron could be explained by new physics, with the emphasis on the RS model and its extensions. Because the KK gluons have almost pure vector couplings to quarks, one finds generically larger contributions to the total inclusive cross section than to the asymmetric cross section in the RS model. This leads to a negative correction to A t FB , that is defined as the ration of the two. The measurement however suggests an enhancement. This result could be generalized to all new physics with primarily vectorial couplings and its robustness under the inclusion of interference effects with NLO QCD diagrams has been confirmed. The almost axial vector couplings of the other linear combination of gauge fields from the SU(3)D × SU(3)S → SU(3)C breaking in the extended model does already lead to a suppression of the asymmetric cross section and consequentially leads to an even worse fit, which is in agreement with the general expectations of resonances with axial vector couplings. In contrast to ɛK, A t FB is very sensitive to the boundary conditions of the color-charged 5D gauge bosons and it could be shown that the BCs imposed by direct detection bounds and the Yukawa couplings guarantee that the effects are always suppressed by the localization of the up quarks and are therefore rendered very small.
A Generating Parameter Points In order to generate a point in the parameter space, we have to fix 38 (real) parameters. These are the 36 real parameters corresponding to the 18 complex entries of the 5D Yukawa matrices, the KK scale MKK and the remaining cu3-parameter corresponding to the wave function F (cu3 ) which we chose in the Froggatt-Nielsen analysis to derive the formulas (2.163), (2.164), (2.165) and (2.165). For the implementation of the parameter scan we the program Mathematica was used and the functions mentioned in this chapter will refer to predefined functions within Mathematica, if not stated otherwise. The code conducts the following steps: 1. Random Yukawas In the first step 18 random complex numbers are produced in the range yij ∈ [0.3, 3]. The random number generator is MersenneTwister, which turned out to be the fastest. 2. First χ 2 Test From these numbers the profile-independent Wolfenstein parameters ¯η, ¯η are computed. If they fail to minimise χ 2 [Xi] = � i � �2 Xi − µi , with Xi = (¯η, ¯ρ), (A.1) σ(Xi) the respective point is rejected. The central values are experimental data µi = (¯ρexp, ¯ηexp) (see Appendix C for the reference) and the variance corresponds to one experimental σ. Interestingly, the code fails to produce acceptable points, if this condition is implemented as an upper bound, like χ 2 [¯η, ¯ρ] < 2, even if the bound is lowered significantly. Therefore the points are required to yield the solution of a FindMinimum condition. 3. Random cu3 The ZMA profile F (cu3 ), defined in (2.150) is randomised within a range F (cu3 ) ∈ (0, Fmax). With the help of experimental values for the remaining Wolfenstein parameters λ and A as well as for the quark masses, the other zero mode profiles are computed according to the formulas in the Froggatt-Nielsen analysis (2.164), (2.165) and (2.165). The distributions for the localization parameters are shown in Figure A.1. 4. Second χ 2 Test In the last step the KK scale is randomised within MKK ∈ [10 3 , 10 4 ] GeV and with the help of the Yukawa matrices and the parameters F (cQ,q), already determined in the third step, the quark masses and the CKM matrix are computed, according to (2.158) and (2.159). These expressions have to pass another χ 2 test,
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:
Page 54 and 55:
Page 56 and 57:
Page 58 and 59:
Page 60 and 61:
Page 62 and 63:
Page 64 and 65:
Page 66 and 67:
Page 68 and 69:
Page 70 and 71:
Page 72 and 73:
Page 74 and 75:
Page 76 and 77:
Page 78 and 79:
Page 80 and 81:
Page 82 and 83:
Page 84 and 85:
Page 86 and 87:
Page 88 and 89:
Page 90 and 91:
Page 92 and 93:
Page 94 and 95:
Page 96 and 97:
Page 98 and 99:
Page 100 and 101:
Page 102 and 103:
92 Chapter 3. Solving the Flavor Pr
Page 104 and 105:
Page 106 and 107:
Page 108 and 109:
Page 110 and 111:
100 Chapter 3. Solving the Flavor P
Page 112 and 113:
Page 114 and 115:
Page 116 and 117:
Page 118 and 119:
Page 120 and 121:
Page 122 and 123:
Page 124 and 125:
Page 126 and 127:
Page 128 and 129:
Page 130 and 131:
Page 132 and 133:
Page 134 and 135:
Page 136 and 137: 126 Chapter 3. Solving the Flavor P
Page 156 and 157: 146 Chapter 4. The Asymmetry in Top
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

Create successful ePaper yourself

Delete template?

Save as template?