Mihir P. Worah

CP asymmetries in B decays with new physics in decay amplitudes

Abstract We make a systematic analysis of the effects of new physics in the B decay amplitudes on the CP asymmetries in neutral B decays. Although these are expected to be smaller than new physics effects on the mixing amplitude, they are easier to probe in some cases. The effects of new contributions to the mixing amplitude are felt universally across all decay modes, whereas the effects of new decay amplitudes could vary from mode to mode. In particular the prediction that the CP asymmetries in the Bd decay modes with b → c c s , b → c c d , b → c u d and b → s s s should all measure the same quantity (sin 2β in the Standard Model) could be violated. Since the above Standard Model prediction is very precise, new decay amplitudes which are a few percent of the Standard Model amplitudes can be probed. Three examples of models where measurable effects are allowed are given: effective supersymmetry, models with enhanced chromomagnetic dipole operators, and supersymmetry without R parity.

A model independent construction of the unitarity triangle

Abstract In a large class of models, the only significant new physics effect on the CP asymmetries in B → ψK s and B → ππ decays is a new contribution to the B - B mixing amplitude. This allows a model independent construction of the CKM Unitarity Triangle (up to hadronic uncertainties). Furthermore, the contributions to the mixing from the Standard Model and from the new physics can be disentangled. A serious obstacle to this analysis is an eightfold discrete ambiguity in solving for the angles of the triangle. Several ways to reduce the ambiguity either by making further measurements, or by making further assumptions about the nature of the new physics are described.

Probing the flavor and CP structure of supersymmetric models with K→πνν̄ decays

We study the implications of various supersymmetric models on the rare

Supersymmetric baryogenesis at the electroweak phase transition

K^+ \to \pi^+ \nu \bar\nu

CP Asymmetry in B_d --> phi K_S: Standard Model Pollution

and

Supersymmetric Baryogenesis and Flavor Physics

K_L \to \pi^0 \nu \bar\nu

New supersymmetric CP -violating contribution to neutral meson mixing

decays. Although large effects are possible in generic supersymmetric models, most of the known supersymmetric flavor models lead to negligible effects. Thus, it is likely that one can get information about CKM matrix elements from these decays even in the presence of supersymmetry. Moreover, the possibility of large contributions to

CP asymmetry in B{sub d}{r_arrow}{phi}K{sub S}: Standard model pollution

K \to \pi \nu \bar\nu

Atmospheric \nu_\mu Deficit from Decoherence

in generic supersymmetric models can be constrained by improved bounds on

CP asymmetry in B{sub d}K{sub S}: Standard model pollution

D-\bar D