Measurement of the CP violating phase \phi_s in Bs->J/\psi f0(980)

TL;DR

This paper reports a measurement of the CP violating phase _s in Bs decays to J/ f0(980) using LHCb data, providing a new channel to probe CP violation and potential new physics beyond the Standard Model.

Contribution

First measurement of _s in Bs  J/ f0(980) decay channel, expanding the methods to study CP violation in Bs mesons.

Findings

Measured _s as -0.44 1 0.44 0.02 rad, consistent with Standard Model.

Used 0.41/fb of LHCb data focusing on the CP odd eigenstate.

Demonstrated the viability of the J/ f0(980) channel for CP violation studies.

Abstract

Measurement of mixing-induced CP violation in Bs decays is of prime importance in probing new physics. So far only the channel Bs->J/\psi \phi\ has been used. Here we report on a measurement using an LHCb data sample of 0.41/fb in the CP odd eigenstate J\psi f0(980), where f0(980)->\pi+ \pi-. A time dependent fit of the data with the Bs lifetime and the difference in widths of the heavy and light eigenstates constrained to the values obtained from Bs-> J/\psi\phi\ yields a value of the CP violating phase of -0.44 +/- 0.44 +/- 0.02 rad, consistent with the Standard Model expectation.