Measuring the CP Violating Phase in Bs Mixing Using Bs -> J/\psi f_0(980)

TL;DR

This paper proposes using the decay Bs -> J/psi f0(980) to measure the CP violating phase in Bs mixing, achieving high sensitivity and simplifying analysis compared to other methods.

Contribution

It introduces a novel approach utilizing Bs -> J/psi f0(980) decay for measuring CP violation, avoiding complex transversity analysis.

Findings

Sensitivity of +/- 0.050 rad with 2/fb of data

Improved sensitivity to +/- 0.044 rad with additional decay modes

Method simplifies analysis by using CP eigenstates

Abstract

We show that the decay Bs -> J/psi f0(980), f0(980)->pi+ pi- can be used to measure the CP violating phase in Bs mixing, -2\beta_s, and estimate the sensitivity as +/- 0.050 rad, for 2/fb of LHCb data. After adding in the related Bs -> J/psi eta', \eta' -> rho gamma mode, the sensitivity improves to +/- 0.044 rad. Use of these CP eigenstates obviates the need for a transversity analysis that must be used in the case of Bs -> J/psi phi decays.