The polarization of photons produced in radiative B-s(0) decays is studied for the first time. The data are recorded by the LHCb experiment in pp collisions corresponding to an integrated luminosity ...of 3 fb(-1) at center-of-mass energies of 7 and 8 TeV. A time-dependent analysis of the B-s(0) ->phi gamma decay rate is conducted to determine the parameter A(Delta), which is related to the ratio of right-over left-handed photon polarization amplitudes in b -> s gamma transitions. A value of A(Delta) = -0.98(-0.52)(-0.20)(+0.46)(+0.23) is measured. This result is consistent with the standard model prediction within 2 standard deviations.
A time-dependent angular analysis of B0s→ψ(2S)ϕ decays is performed using data recorded by the LHCb experiment. The data set corresponds to an integrated luminosity of 3.0\invfb collected during Run ...1 of the LHC. The CP-violating phase and decay-width difference of the B0s system are measured to be ϕs=0.23+0.29−0.28±0.02 rad and ΔΓs=0.066+0.041−0.044±0.007 ps−1, respectively, where the first uncertainty is statistical and the second systematic. This is the first time that ϕs and ΔΓs have been measured in a decay containing the ψ(2S) resonance.
Production cross-sections of prompt charm mesons are measured with the first data from $pp$ collisions at the LHC at a centre-of-mass energy of $13\,\mathrm{TeV}$. The data sample corresponds to an ...integrated luminosity of $4.98 \pm 0.19\,\mathrm{pb}^{-1}$ collected by the LHCb experiment. The production cross-sections of $D^{0}$, $D^{+}$, $D_{s}^{+}$, and $D^{*+}$ mesons are measured in bins of charm meson transverse momentum, $p_{\mathrm{T}}$, and rapidity, $y$, and cover the range $0 < p_{\mathrm{T}} < 15\,\mathrm{GeV}/c$ and $2.0 < y < 4.5$. The ratios of the integrated cross-sections between charm mesons agree with previously measured fragmentation fractions. The inclusive $c\overline{c}$ cross-section within the range of $0 < p_{\mathrm{T}} < 8\,\mathrm{GeV}/c$ is found to be \ \sigma(pp \to c\overline{c}X) = 2940 \pm 3 \pm 180 \pm 160\,\mu\mathrm{b} \ where the uncertainties are due to statistical, systematic and fragmentation fraction uncertainties, respectively.
The data sample of Λ0b→J/ψpK− decays acquired with the LHCb detector from 7 and 8~TeV pp collisions, corresponding to an integrated luminosity of 3 fb−1, is inspected for the presence of J/ψp or ...J/ψK− contributions with minimal assumptions about K−p contributions. It is demonstrated at more than 9 standard deviations that Λ0b→J/ψpK− decays cannot be described with K−p contributions alone, and that J/ψp contributions play a dominant role in this incompatibility. These model-independent results support the previously obtained model-dependent evidence for P+c→J/ψp charmonium-pentaquark states in the same data sample.
An angular analysis of the $B^{0}\rightarrow K^{*0}(\rightarrow K^{+}\pi^{-})\mu^{+}\mu^{-}$ decay is presented. The dataset corresponds to an integrated luminosity of $3.0\,{\mbox{fb}^{-1}}$ of $pp$ ...collision data collected at the LHCb experiment. The complete angular information from the decay is used to determine $C\!P$-averaged observables and $C\!P$ asymmetries, taking account of possible contamination from decays with the $K^{+}\pi^{-}$ system in an S-wave configuration. The angular observables and their correlations are reported in bins of $q^2$, the invariant mass squared of the dimuon system. The observables are determined both from an unbinned maximum likelihood fit and by using the principal moments of the angular distribution. In addition, by fitting for $q^2$-dependent decay amplitudes in the region $1.1<q^{2}<6.0\mathrm{\,Ge\kern -0.1em V}^{2}/c^{4}$, the zero-crossing points of several angular observables are computed. A global fit is performed to the complete set of $C\!P$-averaged observables obtained from the maximum likelihood fit. This fit indicates differences with predictions based on the Standard Model at the level of 3.4 standard deviations. These differences could be explained by contributions from physics beyond the Standard Model, or by an unexpectedly large hadronic effect that is not accounted for in the Standard Model predictions.
The $B_s^0 \rightarrow J/\psi \phi \phi$ decay is observed in $pp$ collision data corresponding to an integrated luminosity of 3 fb$^{-1}$ recorded by the LHCb detector at centre-of-mass energies of ...7 TeV and 8 TeV. This is the first observation of this decay channel, with a statistical significance of 15 standard deviations. The mass of the $B_s^0$ meson is measured to be $5367.08\,\pm \,0.38\,\pm\, 0.15$ MeV/c$^2$. The branching fraction ratio $\mathcal{B}(B_s^0 \rightarrow J/\psi \phi \phi)/\mathcal{B}(B_s^0 \rightarrow J/\psi \phi)$ is measured to be $0.0115\,\pm\, 0.0012\, ^{+0.0005}_{-0.0009}$. In both cases, the first uncertainty is statistical and the second is systematic. No evidence for non-resonant $B_s^0 \rightarrow J/\psi \phi K^+ K^-$ or $B_s^0 \rightarrow J/\psi K^+ K^- K^+ K^-$ decays is found.
A search for B0(s)→K0SK∗(892)0 decays is performed using pp collision data, corresponding to an integrated luminosity of 1.0 fb−1, collected with the LHCb detector at a centre-of-mass energy of 7 ...TeV. The B0s→K0SK∗(892)0 decay is observed for the first time, with a significance of 7.1 standard deviations. The branching fraction is measured to beB(B0s→K0SK∗(892)0)=(10.9±2.5±1.2)×10−6,where the first uncertainty is statistical and the second is systematic. No evidence is found for the decay B0→K0SK∗(892)0 and an upper limit is set on the branching fraction, B(B0→K0SK∗(892)0)<0.64 ×10−6, at 90% confidence level. All results are consistent with Standard Model predictions.
The first observation of the B0s→D¯0K0S decay mode and evidence for the B0s→D¯∗0K0S decay mode are reported. The data sample corresponds to an integrated luminosity of 3.0 fb−1 collected in pp ...collisions by LHCb at center-of-mass energies of 7 and 8 TeV. The branching fractions are measured to beB(B0s→D¯0K¯0)B(B0s→D¯∗0K¯0)=(4.3±0.5(stat)±0.3(syst)±0.3(frag)±0.6(norm))×10−4,=(2.8±1.0(stat)±0.3(syst)±0.2(frag)±0.4(norm))×10−4,where the uncertainties are due to contributions coming from statistical precision, systematic effects, and the precision of two external inputs, the ratio fs/fd and the branching fraction of B0→D¯0K0S, which is used as a calibration channel.
Time-dependent CP asymmetries in the decay rates of the singly Cabibbo-suppressed decays D0→K−K+ and D0→π−π+ are measured in pp collision data corresponding to an integrated luminosity of 3.0 fb−1 ...collected by the LHCb experiment. The D0 mesons are produced in semileptonic b-hadron decays, where the charge of the accompanying muon is used to determine the initial state as D0 or D¯0. The asymmetries in effective lifetimes between D0 and D¯0 decays, which are sensitive to indirect CP violation, are determined to beAΓ(K−K+)=(−0.134±0.077+0.026−0.034)% ,AΓ(π−π+)=(−0.092±0.145+0.025−0.033)% ,where the first uncertainties are statistical and the second systematic. This result is in agreement with previous measurements and with the hypothesis of no indirect CP violation in D0 decays.
Measurements are presented of the branching fractions of the decays B0s→D∓sK± and B0→D−sK+ relative to the decays B0s→D−sπ+ and B0→D−π+, respectively. The data used correspond to an integrated ...luminosity of 3.0 fb−1 of proton-proton collisions. The ratios of branching fractions are B(B0s→D∓sK±)B(B0s→D−sπ+)=0.0752±0.0015±0.0019 and B(B0→D−sK+)B(B0→D−π+)=0.0129±0.0005±0.0008, where the uncertainties are statistical and systematic, respectively.
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