Observation of time-reversal violation in B mesons

par Prof. Fernando Martinez-Vidal (University of Valencia, Spain) (Instituto de Física Corpuscular (University of Valencia-CSIC) and Department of Atomic, Molecular and Nuclear Physics.)

jeudi 14 févr. 2013, 14:00 → 15:00 Europe/Paris

1222-RC-08 (LPNHE)

The mechanism of CP violation in the quark sector of weak interactions, as arising from the single physical phase in the three-generation CKM matrix, has been validated by more than a decade of intense experimental work probing CP violation, particularly with the studies with B mesons at B factories. Since the Standard Model theory is CPT invariant, it predicts a “weak arrow of time” matching the large observed matter-antimatter asymmetry in B mesons. However, there has been no direct observation of the expected, large time reversal (T) asymmetry. In this seminar we shall discuss how the BABAR experiment at SLAC National Accelerator Laboratory has conducted a new data analysis where the decays of entangled neutral B mesons allow comparisons between the rates of four different transitions and their inverse, as a function of the time evolution of the B meson. The results lead to the first direct observation with high significance of T non-invariance through the exchange of initial and final states in transitions that can only be connected by a T symmetry transformation.

Transparents Tviolation-LPNHE-02-2013.pdf