This paper presents the measurement of the relative width difference ΔΓd/Γd of the B0‐ B¯ 0 system using the data collected by the ATLAS experiment at the LHC in pp collisions at s=7 TeV and s=8 TeV and corresponding to an integrated luminosity of 25.2 fb−1. The value of ΔΓd/Γd is obtained by comparing the decay-time distributions of B0 → J/ψKS and B0 → J/ψK*0(892) decays. The result is ΔΓd/Γd = (−0.1±1.1 (stat.)± 0.9 (syst.)) × 10−2. Currently, this is the most precise single measurement of ΔΓd/Γd. It agrees with the Standard Model prediction and the measurements by other experiments.

Aaboud, M., Aad, G., Abbott, B., Abdallah, J., Abdinov, O., Abeloos, B., et al. (2016). Measurement of the relative width difference of the B0‐ B¯ 0 system with the ATLAS detector. JOURNAL OF HIGH ENERGY PHYSICS, 2016(6) [10.1007/JHEP06(2016)081].

Measurement of the relative width difference of the B0‐ B¯ 0 system with the ATLAS detector

F. Ceradini;B. Di Micco;R. Di Nardo;D. Orestano;F. Petrucci;D. Puddu;G. Salamanna;