LHCb

Abstract:

We analyze a sample of 3×106 quantum-correlated D0D̄0 pairs from 818pb-1 of e+e- collision data collected with the CLEO-c detector at Ecm=3.77GeV, to give an updated measurement of cos δ and a first determination of sin δ, where δ is the relative strong phase between doubly Cabibbo-suppressed D0→K+π- and Cabibbo-favored D ̄0→K+π- decay amplitudes. With no inputs from other experiments, we find cos δ=0.81-0.18-0.05+0.22+0.07, sin δ=-0.01±0.41±0.04, and |δ|=(10-53-0+28+13)°. By including external measurements of mixing parameters, we find alternative values of cos δ=1.15-0.17-0.08+0.19+0.00, sin δ=0.56-0.31-0.20+0.32+0.21, and δ=(18-17+11)°. Our results can be used to improve the world average uncertainty on the mixing parameter y by approximately 10%. © 2012 American Physical Society.

Abstract:

This contribution reports on recent LHCb achievements in the pursuit of CKM triangle measurements and probes of CP violation in the charm system. These results are based on the 2010 dataset or, in some cases, preliminary results using the data collected by summer 2011. © Owned by the authors 2012.

Abstract:

Of the three angles that make up the CKM matrix, the least well known is γ A precision measurement of this quantity is highly desirable as it forms one of the arbitrary parameters in the Standard Model. Moreover, this is the one angle of the CKM triangle that can be determined in channels that occur via tree-level decays. While loop-level processes could have sensitivity to physics beyond the standard model, tree level processes are expected to be unaltered. Hence a measurement of in tree level processes leads to a standard model benchmark measurement against which other loop-driven measurements can be compared. The measurements described here are the latest developments from LHCb involving the decay B+ → DK+, where the D meson is either a D0 or a D̄0 and the final state of the D meson is accessible from either flavour state.