Precision Physics with B^0_s -> J/psi phi at the LHC: The Quest for New Physics

TL;DR

This paper examines the impact of hadronic uncertainties and long-distance QCD effects on CP violation measurements in B_s decays at the LHC, proposing methods to control these uncertainties for new physics searches.

Contribution

It introduces a novel analysis approach to control hadronic uncertainties in B_s decay CP violation measurements using angular distributions and SU(3) symmetry considerations.

Findings

Hadronic uncertainties can be mitigated through angular analysis of related decay modes.

Long-distance QCD effects may influence CP-violating phase measurements.

SU(3)-breaking effects impose limits on theoretical precision, but internal consistency checks can help.

Abstract

CP-violating effects in the time-dependent angular distribution of the B^0_s -> J/psi[-> ell^+ ell^-] phi[-> K^+K^-] decay products play a key role for the search of new physics. The hadronic Standard-Model uncertainties are related to doubly Cabibbo-suppressed penguin contributions and are usually assumed to be negligibly small. In view of recent results from the Tevatron and the quickly approaching start of the data taking at the LHC, we have a critical look at the impact of these terms, which could be enhanced through long-distance QCD phenomena, and explore the associated uncertainty for the measurement of the CP-violating B^0_s-\bar B^0_s mixing phase. We point out that these effects can actually be controlled by means of an analysis of the time-dependent angular distribution of the B^0_s -> J/psi[-> ell^+ ell^-] \bar K^{*0}[-> pi^+ K^-] decay products, and illustrate this through numerical studies. Moreover, we discuss SU(3)-breaking effects, which limit the theoretical accuracy of our method, and suggest internal consistency checks of SU(3).