First observation of the decay

Physics Letters B, 2012

The first observation of the decay B 0 s → K * 0 K * 0 is reported using 35 pb −1 of data collected by LHCb in proton-proton collisions at a centre-of-mass energy of 7 TeV. A total of 49.8 ± 7.5 B 0 s → (K + π −)(K − π +) events are observed within ±50 MeV/c 2 of the B 0 s mass and 746 MeV/c 2 < m Kπ < 1046 MeV/c 2 , mostly coming from a resonant B 0 s → K * 0 K * 0 signal. The branching fraction and the CP-averaged K * 0 longitudinal polarization fraction are measured to be B B 0 s → K * 0 K * 0 = (2.81 ± 0.46(stat.) ± 0.45(syst.) ± 0.34 (f s /f d)) × 10 −5 and f L = 0.31 ± 0.12(stat.) ± 0.04(syst.).

2011

The first observation of the decay B 0 s → K * 0 K * 0 is reported using 35 pb −1 of data collected by LHCb in proton-proton collisions at a centre-of-mass energy of 7 TeV. A total of 49.8 ± 7.5 signal events are observed, with a significance of 10.9 σ. The branching fraction and the CP -averaged K * 0 longitudinal polarization fraction are measured to be B B 0 s → K * 0 K * 0 = (2.81 ± 0.46(stat.) ± 0.45(syst.) ± 0.34 (f s /f d )) × 10 −5 and f L = 0.31 ± 0.12(stat.) ± 0.04(syst.).

2011

The first observation of the decay B 0 s → K * 0 K * 0 is reported using 35 pb −1 of data collected by LHCb in proton-proton collisions at a centre-of-mass energy of 7 TeV. A total of 49.8 ± 7.5 B 0 s → (K + π − )(K − π + ) events are observed within ±50 MeV/c 2 of the B 0 s mass and 746 MeV/c 2 < m Kπ < 1046 MeV/c 2 , mostly coming from a resonant B 0 s → K * 0 K * 0 signal. The branching fraction and the CP -averaged K * 0 longitudinal polarization fraction are measured to be B B 0 s → K * 0 K * 0 = (2.81 ± 0.46(stat.) ± 0.45(syst.) ± 0.34 (f s /f d )) × 10 −5 and f L = 0.31 ± 0.12(stat.) ± 0.04(syst.).

Nature, 2015

Physical review letters, 2017

Using proton-proton collision data corresponding to an integrated luminosity of 3.0 fb^{-1}, recorded by the LHCb detector at center-of-mass energies of 7 and 8 TeV, the B_{c}^{+}→D^{0}K^{+} decay is observed with a statistical significance of 5.1 standard deviations. By normalizing to B^{+}→D[over ¯]^{0}π^{+} decays, a measurement of the branching fraction multiplied by the production rates for B_{c}^{+} relative to B^{+} mesons in the LHCb acceptance is obtained, R_{D^{0}K}=(f_{c}/f_{u})×B(B_{c}^{+}→D^{0}K^{+})=(9.3_{-2.5}^{+2.8}±0.6)×10^{-7}, where the first uncertainty is statistical and the second is systematic. This decay is expected to proceed predominantly through weak annihilation and penguin amplitudes, and is the first B_{c}^{+} decay of this nature to be observed.

Journal of High Energy Physics, 2015

An angular analysis of the decay B 0 s → K * 0 K * 0 is performed using pp collisions corresponding to an integrated luminosity of 1.0 fb −1 collected by the LHCb experiment at a centre-of-mass energy √ s = 7 TeV. A combined angular and mass analysis separates six helicity amplitudes and allows the measurement of the longitudinal polarisation fraction f L = 0.201 ± 0.057 (stat.) ± 0.040 (syst.) for the B 0 s → K * (892) 0 K * (892) 0 decay. A large scalar contribution from the K * 0 (1430) and K * 0 (800) resonances is found, allowing the determination of additional CP asymmetries. Triple product and direct CP asymmetries are determined to be compatible with the Standard Model expectations. The branching fraction B(B 0 s → K * (892) 0 K * (892) 0) is measured to be (10.8 ± 2.1 (stat.) ± 1.4 (syst.) ± 0.6 (f d /f s)) × 10 −6 .

2012

The first observation of the decay B 0 → D 0 K + K − is reported from an analysis of 0.62 fb −1 of pp collision data collected with the LHCb detector. Its branching fraction is measured relative to that of the topologically similar decay

2011

The first observation of the decay B 0 s → D 0 K * 0 using pp data collected by the LHCb detector at a centre-of-mass energy of 7 TeV, corresponding to an integrated luminosity of 36 pb −1 , is reported. A signal of 34.4 ± 6.8 events is obtained and the absence of signal is rejected with a statistical significance of more than nine standard deviations. The B 0 s → D 0 K * 0 branching fraction is measured relative to that of B 0 → D 0 ρ 0 :

2011

The first observation of the decay B 0 s → D 0 K * 0 using pp data collected by the LHCb detector at a centre-of-mass energy of 7 TeV, corresponding to an integrated luminosity of 36 pb −1 , is reported. A signal of 34.4 ± 6.8 events is obtained and the absence of signal is rejected with a statistical significance of more than nine standard deviations. The B 0 s → D 0 K * 0 branching fraction is measured relative to that of B 0 → D 0 ρ 0 :

Physics Letters B, 2016

The angular distributions and the differential branching fraction of the decay B 0 → K * (892) 0 µ + µ − are studied using data corresponding to an integrated luminosity of 20.5 fb −1 collected with the CMS detector at the LHC in pp collisions at √ s = 8 TeV. From 1430 signal decays, the forward-backward asymmetry of the muons, the K * (892) 0 longitudinal polarization fraction, and the differential branching fraction are determined as a function of the dimuon invariant mass squared. The measurements are among the most precise to date and are in good agreement with standard model predictions.