Morii, MasahiroFranklin, MelissaHuth, JohnLopez Mateos, DMercurio, KevinSkottowe, Hugh PhilipSpearman, William2020-05-082016-06ATLAS Collaboration. 2016. Measurement of the relative width difference of the B0-B ̄0 system with the ATLAS detector. Journal of High Energy Physics 2016: 81.1029-8479http://nrs.harvard.edu/urn-3:HUL.InstRepos:42665078Abstract: This paper presents the measurement of the relative width difference ∆Γd/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 25.2fb−1. The value of ∆Γd/Γd is obtained by comparing the decay-time distributions of B0 → J/ψKS and B0 → J/ψK∗0(892) decays. The result is ∆Γd/Γd = (−0.1±1.1 (stat.)± 0.9 (syst.)) × 10−2. Currently, this is the most precise single measurement of ∆Γd/Γd. It agrees with the Standard Model prediction and the measurements by other experiments.en-USJournal Article2018-07-2620162020-05-0810.1007/jhep06(2016)081