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.
A binned Dalitz plot analysis of the decays B0→DK∗0, with D→K0Sπ+π− and K0SK+K−, is performed to measure the observables x± and y±, which are related to the CKM angle γ and the hadronic parameters of ...the decays. The D decay strong phase variation over the Dalitz plot is taken from measurements performed at the CLEO-c experiment, making the analysis independent of the D decay model. With a sample of proton-proton collision data, corresponding to an integrated luminosity of 3.0fb−1, collected by the LHCb experiment, the values of the CP violation parameters are found to be x+=0.05±0.35±0.02, x−=−0.31±0.20±0.04, y+=−0.81±0.28±0.06 and y−=0.31±0.21±0.05, where the first uncertainties are statistical and the second systematic. These observables correspond to values γ = (71±20)∘, rB0=0.56±0.17 and δB0=(204+21−20)∘. The parameters rB0 and δB0 are the magnitude ratio and strong phase difference between the suppressed and favoured B0 decay amplitudes, and have been measured in a region of ±50 MeV/c2 around the K∗(892)0 mass and with the magnitude of the cosine of the K∗(892)0 helicity angle larger than 0.4.
A search is performed for the charmless three-body decays of the Λ0b and Ξ0b baryons to the final states Λh+h′−, where h(′)=π or K. The analysis is based on a data sample, corresponding to an ...integrated luminosity of 3fb−1 of pp collisions, collected by the LHCb experiment. The Λ0b→ΛK+π− and Λ0b→ΛK+K− decays are observed for the first time and their branching fractions and CP asymmetry parameters are measured. Evidence is seen for the Λ0b→Λπ+π− decay and limits are set on the branching fractions of Ξ0b baryon decays to the Λh+h′− final states.
We perform a search for near-threshold Ξ0b resonances decaying to Ξ−bπ+ in a sample of proton-proton collision data corresponding to an integrated luminosity of 3 fb−1 collected by the LHCb ...experiment. We observe one resonant state, with the following properties:m(Ξ∗0b)−m(Ξ−b)−m(π+)=15.727±0.068(stat)±0.023(syst)MeV/c2,Γ(Ξ∗0b)=0.90±0.16(stat)±0.08(syst)MeV.This confirms the previous observation by the CMS collaboration. The state is consistent with the JP=3/2+ Ξ∗0b resonance expected in the quark model. This is the most precise determination of the mass and the first measurement of the natural width of this state. We have also measured the ratioσ(pp→Ξ∗0bX)B(Ξ∗0b→Ξ−bπ+)σ(pp→Ξ−bX)=0.27±0.03(stat)±0.01(syst).
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