Measurement of the B0s→μ+μ− decay properties and search for the B0→μ+μ− and B0s→μ+μ−γ decays

Physical Review D - Particles, Fields, Gravitation and Cosmology. 2022. Vol. 105. No. 1. Article 012010.

Aaij R., Abellán Beteta C., Ackernley T., Adeva B., Adinolfi M., Afsharnia H., Aidala C. A., Arzymatov K., Belavin V., Boldyrev A., Borisyak M., Derkach D., Hushchyn M., Karpov M., Maevskiy A., Popov S., Ratnikov F., Ryzhikov A., Ustyuzhanin A.

An improved measurement of the decay B0s→μ+μ− and searches for the decays B0→μ+μ− and B0s→μ+μ−γ are performed at the LHCb experiment using data collected in proton-proton collisions at s√=7, 8and 13 TeV, corresponding to integrated luminosities of 1, 2 and 6 fb−1, respectively. The B0s→μ+μ− branching fraction and effective lifetime are measured to be Br(B0s→μ+μ−)=(3.09+0.46+0.15−0.43−0.11)×10−9 and τ(B0s→μ+μ−)=(2.07±0.29±0.03) ps, respectively, where the uncertainties include both statistical and systematic contributions. No significant signal for B0→μ+μ− and B0s→μ+μ−γ decays is found and the upper limits Br(B0→μ+μ−)<2.6×10−10 and. Br(B0s→μ+μ−γ)<2.0×10−9 at 95% confidence level are determined, where the latter is limited to the range mμμ>4.9 GeV/c2. Additionally, the ratio between the B0→μ+μ− and B0s→μ+μ− branching fractions is measured to be Rμ+μ−<0.095 at 95% confidence level. The results are in agreement with the Standard Model predictions.

Keywords: data analysis, B physics, High Energy Physics - Experiment

Publication based on the results of: Machine learning to check and improve the quality of data collected at the Large Hadron Collider and other particle physics experiments (2022)