B physics
In B physics, HIP group provided in the past a major contribution to the analysis of the decay channel Bs → J/ψ φ(1020), where the J/ψ decays to two muons and the φ meson to two kaons. This decay channel probes the weak mixing phase φs . This parameter is interesting since it can be predicted accurately, and deviations from the standard model predictions can indicate contributions from new physics beyond the standard model. The channel is one of the CMS flagship analyses in heavy flavour physics. Results of the weak mixing phase and the decay width difference were published in PLB in 2016 [1].
In addition the weak mixing phase analysis, HIP group has developed the first flavour tagging algorithm in the CMS and participated to the validation of the current version of the tagging tool. Flavour tagging identifies the flavour of the b quark inside the Bs meson and is a crucial part of the weak phase analysis, since it improves the measurement precision of the mixing phase.
Currently HIP group participates into Run I physics analysis of B hadron lifetimes (Bs, Bd, B+, Bc, Λb), where it is responsible for Bs lifetime measurement through J/ψ φ(1020) channel. The HIP B-physics plans to include finalising the ongoing Run I physics analysis of B hadron lifetimes, and an improved measurement of the weak mixing phase with Run II data.
[1] CMS Collaboration, Measurement of the CP-violating weak phase φs and the decay width
difference ΔΓs using the Bs →J/ψ φ(1020) decay channel in pp collisions at √s = 8 TeV,
arXiv:1507.07527 [hep-ex], submitted for publication in Phys. Lett. B (2015).