Ricerc@Sapienza

We report the measurements of the CP -violating parameters in Bs0 ? Ds?K± decays observed in pp collisions, using a data set corresponding to an integrated luminosity of 3.0 fb?1 recorded with the LHCb detector. We measure Cf = 0.73 ± 0.14 ± 0.05, Af?? = 0.39 ± 0.28 ± 0.15, Af=0.31±0.28±0.15, Sf = ?0.52 ± 0.20 ± 0.07, Sf¯= ? 0.49 ± 0.20 ± 0.07 , where the uncertainties are statistical and systematic, respectively. These parameters are used together with the world-average value of the Bs0 mixing phase, ?2?s, to obtain a measurement of the CKM angle ? from Bs0 ? Ds?K± decays, yielding ?

A flavour-tagged decay-time-dependent amplitude analysis of Bs0 ? (K+??)(K??+) decays is presented in the K±?? mass range from 750 to 1600MeV/c2. The analysis uses pp collision data collected with the LHCb detector at centre-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3.0 fb?1. Several quasi-two-body decay modes are considered, corresponding to K±?? combinations with spin 0, 1 and 2, which are dominated by the K0*(800)0 and K0*(1430)0, the K*(892)0 and the K2*(1430)0 resonances, respectively.

A search for decays of Bc+ mesons to two charm mesons is performed for the first time using data corresponding to an integrated luminosity of 3.0fb?1, collected by the LHCb experiment in pp collisions at centre-of-mass energies of 7 and 8 TeV. The decays considered are Bc+?D(s)(?)+D?(?)0 and Bc+?D(s)(?)+D(?)0, which are normalised to high-yield B+?D(s)+D?0 decays. No evidence for a signal is found and limits are set on twelve Bc+ decay modes.

The CP asymmetry in B? ? Ds?D0 and B? ? D?D0 decays is measured using LHCb data corresponding to an integrated luminosity of 3.0 fb?1, collected in pp collisions at centre-of-mass energies of 7 and 8 TeV. The results are ACP(B??Ds?D0)=(?0.4±0.5±0.5)%andACP(B??D?D0)=(2.3±2.7±0.4)%, where the first uncertainties are statistical and the second systematic. This is the first measurement of ACP(B??Ds?D0) and the most precise determination of ACP(B?? D?D0). Neither result shows evidence of CP violation.

A measurement of the CP asymmetries Sf and Sf¯ in B0 ? D??± decays is reported. The decays are reconstructed in a dataset collected with the LHCb experiment in proton-proton collisions at centre-of-mass energies of 7 and 8 TeV and corresponding to an integrated luminosity of 3.0 fb?1. The CP asymmetries are measured to be Sf = 0.058 ± 0.020(stat) ± 0.011(syst) and Sf¯=0.038±0.020(stat)±0.007(syst). These results are in agreement with, and more precise than, previous determinations. They are used to constrain angles of the unitarity triangle, | sin (2?

A search for the decay B-s(0) -> (K) over bar (*0) mu(+) mu(-) is presented using data sets corresponding to 1.0, 2.0 and 1.6 fb(-1) of integrated luminosity collected during pp collisions with the LHCb experiment at centre-of-mass energies of 7, 8 and 13TeV, respectively. An excess is found over the background-only hypothesis with a significance of 3.4 standard deviations.

The Cabibbo-suppressed decay ?b0 ? ?(2S)p?? is observed for the first time using a data sample collected by the LHCb experiment in proton-proton collisions corresponding to 1.0, 2.0 and 1.9 fb?1 of integrated luminosity at centre-of-mass energies of 7, 8 and 13 TeV, respectively. The ?(2S) mesons are reconstructed in the ?+?? final state. The branching fraction with respect to that of the ?b0 ? ?(2S)pK? decay mode is measured to be ?(?b0??(2S)p??)?(?b0??(2S)pK?)=(11.4±1.3±0.2)%, where the first uncertainty is statistical and the second is systematic. The ?(2S)p and ?(2S)??

The B¯s0??c2K+K? decay mode is observed and its branching fraction relative to the corresponding ?c1 decay mode, in a ±15 MeV/c2 window around the ? mass, is found to be ?(B¯s0??c2K+K?)?(B¯s0??c1K+K?)=(17.1±3.1±0.4±0.9)%, where the first uncertainty is statistical, the second systematic and the third due to the knowledge of the branching fractions of radiative ?c decays. The decay mode B¯s0??c1K+K? allows the Bs0 mass to be measured as m(Bs0)=5366.83±0.25±0.27MeV/c2, where the first uncertainty is statistical and the second systematic.