A time-dependent angular analysis of Bs0→ψ(2S)ϕ decays is performed using data recorded by the LHCb experiment. The data set corresponds to an integrated luminosity of 3.0fb−1 collected during Run 1 of the LHC. The CP-violating phase and decay-width difference of the Bs0 system are measured to be ϕs=0.23−0.28+0.29±0.02rad and ΔΓs=0.066−0.044+0.041±0.007ps−1, respectively, where the first uncertainty is statistical and the second systematic. This is the first time that ϕs and ΔΓs have been measured in a decay containing the ψ(2S) resonance.
Aaij, R., Adeva, B., Adinolfi, M., Ajaltouni, Z., Akar, S., Albrecht, J., … Zucchelli, S. (2016). First study of the CP-violating phase and decay-width difference in Bs0→ψ(2S)ϕ decays. Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 762, 253–262. https://doi.org/10.1016/j.physletb.2016.09.028