New Physics in Bs -> J/psi phi: a General Analysis

TL;DR

This paper explores the possibility of new physics affecting the decay process in Bs -> J/psi phi, which could alter CP violation measurements and explain discrepancies with the Standard Model.

Contribution

It introduces the idea that new physics in the decay process, not just mixing, can significantly impact CP violation measurements in Bs -> J/psi phi.

Findings

New physics can contribute to Bs decay amplitudes.

Predicted polarization-dependent CP asymmetries.

Consistency with existing B decay measurements.

Abstract

Recently, the CDF and D0 collaborations measured indirect CP violation in Bs -> J/psi phi and found a hint of a signal. If taken at face value, this can be interpreted as a nonzero phase of Bs-Bsbar mixing (beta_s), in disagreement with the standard model, which predicts that beta_s ~= 0. In this paper, we argue that this analysis may be incomplete. In particular, there can be new physics (NP) in the bbar -> sbar c cbar decay. If so, the value of beta_s is different than for the case in which NP is assumed to be present only in the mixing. We have examined several models of NP and found that, indeed, there can be significant contributions to the decay. These effects are consistent with measurements in B -> J/psi K* and Bd -> J/psi Ks. Due to the NP in the decay, polarization-dependent indirect CP asymmetries and triple-product asymmetries are predicted in Bs -> J/psi phi.