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T: Fachverband Teilchenphysik
T 6: Elektroschwache Wechselwirkung 1
T 6.4: Talk
Monday, March 24, 2014, 11:45–12:00, P6
Measurement of different b-hadron lifetimes, lifetime ratios and ΔΓd/Γd at LHCb — •Francesca Dordei for the LHCb Gruppe Physikalisches Institut Heidelberg collaboration — Physikalisches Institut, Heidelberg, Germany
Precision measurement of b-hadron lifetimes are an important test of the theoretical approach to b-hadron observables known as Heavy Quark Expansion (HQE). In this talk, a measurement of the absolute lifetimes of the B+, B0 and Bs0 meson and Λb0 baryon lifetimes is presented. To perform these measurements data corresponding to an integrated luminosity of 1.0 fb−1 are used, collected in 2011 with the LHCb detector.
The challenge of precision lifetime measurements is that small decay-time dependent efficiencies and lifetime biases are introduced from a variety of sources, in particular related to the event reconstruction and selection. Given the statistical precision of few fs such biases must be controlled to a very accurate level. Various data-driven methods to correct for these effects have been developed and successfully tested, demonstrating an excellent understanding of the LHCb experiment.
This analysis resulted in the world most precise measurement of the B+ and B0 meson lifetimes. In addition, several lifetime ratios have been measured, to test the predictions of HQE and CPT violation. Finally, from the absolute lifetime measurements, the ratio of the decay width difference to the average width in the B0 system will be presented.