Guy Wilkinson

Abstract:

The determination of the differential branching fraction and the first angular analysis of the decay $B_s^0\to\phi\mu^{+}\mu^{-}$ are presented using data, corresponding to an integrated luminosity of $1.0\,{\rm fb}^{-1}$, collected by the LHCb experiment at $\sqrt{s}=7\,{\rm TeV}$. The differential branching fraction is determined in bins of $q^{2}$, the invariant dimuon mass squared. Integration over the full $q^{2}$ range yields a total branching fraction of ${\cal B}(B_s^0\to\phi\mu^{+}\mu^{-}) = (7.07\,^{+0.64}_{-0.59}\pm 0.17 \pm 0.71)\times 10^{-7}$, where the first uncertainty is statistical, the second systematic, and the third originates from the branching fraction of the normalisation channel. An angular analysis is performed to determine the angular observables $F_{\rm L}$, $S_3$, $A_6$, and $A_9$. The observables are consistent with Standard Model expectations.

Abstract:

A combination of three LHCb measurements of the CKM angle gamma is presented. The decays B->DK and B->Dpi are used, where D denotes an admixture of D0 and D0-bar mesons, decaying into K+K-, pi+pi-, K+-pi-+, K+-pi-+pi+-pi-+, KSpi+pi-, or KSK+K- final states. All measurements use a dataset corresponding to 1.0 fb-1 of integrated luminosity. Combining results from B->DK decays alone a best-fit value of gamma = 72.0 deg is found, and confidence intervals are set gamma in [56.4,86.7] deg at 68% CL, gamma in [42.6,99.6] deg at 95% CL. The best-fit value of gamma found from a combination of results from B->Dpi decays alone, is gamma = 18.9 deg, and the confidence intervals gamma in [7.4,99.2] deg or [167.9,176.4] deg at 68% CL, are set, without constraint at 95% CL. The combination of results from B->DK and B->Dpi decays gives a best-fit value of gamma = 72.6 deg and the confidence intervals gamma in [55.4,82.3] deg at 68% CL, gamma in [40.2,92.7] deg at 95% CL are set. All values are expressed modulo 180 deg, and are obtained taking into account the effect of D0-D0bar mixing.

Abstract:

Using proton-proton collision data collected by the LHCb experiment at √s=7 TeV, corresponding to an integrated luminosity of 1.0 fb -1, the ratio of branching fractions of the B0→D* -π+π-π+ decay relative to the B0→D*-π+ decay is measured to be B(B0→D*-π+π-π+) B(B0→D*-π+)=2.64±0.04(stat)±0. 13(syst). The Cabibbo-suppressed decay B0→D*-K +π-π+ is observed for the first time, and the measured ratio of branching fractions is B(B0→D* -K+π-π+)B(B0→D* -π+π-π+)=(6.47±0. 37(stat)±0.35(syst))×10-2. A search for orbital excitations of charm mesons contributing to the B0→D* -π+π-π+ final state is also performed, and the first observation of the B0→D̄1(2420)0π+π- decay is reported with the ratio of branching fractions B(B0→(D̄1(2420)0→D*-π+) π-π+)B(B0→D*-π +π-π+)=(2.04±0.42(stat)±0. 22(syst))×10-2, where the numerator represents a product of the branching fractions B(B0→D̄1(2420)0π -π+) and B(D̄1(2420)0→D*-π+). © 2013 CERN. Published by the American Physical Society under the terms of the.