Study of DsJ(*) + mesons decaying to D∗ +KS0 and D*0K+ final states

A search is performed for D sJ (*) + mesons in the reactions pp → D ∗ + K S 0 X and pp → D *0 K + X using data collected at centre-of-mass energies of 7 and 8 TeV with the LHCb detector. For the D ∗ + K S 0 final state, the decays D *+ → D 0 π + with D 0 → K − π + and D 0 → K − π + π + π − are used. For D *0 K +, the decay D *0 → D 0 π 0 with D 0 → K − π + is used. A prominent D s1(2536)+ signal is observed in both D ∗ + K S 0 and D *0 K + final states. The resonances D s1 * (2700)+ and D s3 * (2860)+ are also observed, yielding information on their properties, including spin-parity assignments. The decay D s2 * (2573)+ → D ∗ + K S 0 is observed for the first time, at a significance of 6.9 σ, and its branching fraction relative to the D s2 * (2573)+ → D + K S 0 decay mode is measured

Observations of Lambda(0)(b) -> Lambda K+pi(-) and Lambda(0)(b) -> Lambda K+K- decays and searches for other Lambda(0)(b) and Xi(0)(b) decays to Lambda h(+)h '(-) final states

See paper for full list of authors - All figures and tables, along with any supplementary material and additional information, are available at this https URLInternational audienceA 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

Search for Violations of Lorentz Invariance and CPT Symmetry in B-(s)(0) Mixing

Violations of CPT symmetry and Lorentz invariance are searched for by studying interference effects in B^{0} mixing and in B_{s}^{0} mixing. Samples of B^{0}→J/ψK_{S}^{0} and B_{s}^{0}→J/ψK^{+}K^{-} decays are recorded by the LHCb detector in proton-proton collisions at center-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3  fb^{-1}. No periodic variations of the particle-antiparticle mass differences are found, consistent with Lorentz invariance and CPT symmetry. Results are expressed in terms of the standard model extension parameter Δa_{μ} with precisions of O(10^{-15}) and O(10^{-14})  GeV for the B^{0} and B_{s}^{0} systems, respectively. With no assumption on Lorentz (non)invariance, the CPT-violating parameter z in the B_{s}^{0} system is measured for the first time and found to be Re(z)=-0.022±0.033±0.005 and Im(z)=0.004±0.011±0.002, where the first uncertainties are statistical and the second systematic

Observation of the B s 0 → J/ψϕϕ decay

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.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-033.htm

Search for the lepton-flavour violating decay D0→e±μ∓

AbstractA search for the lepton-flavour violating decay D0→e±μ∓ is made with a dataset corresponding to an integrated luminosity of 3.0fb−1 of proton–proton collisions at centre-of-mass energies of 7TeV and 8TeV, collected by the LHCb experiment. Candidate D0 mesons are selected using the decay D⁎+→D0π+ and the D0→e±μ∓ branching fraction is measured using the decay mode D0→K−π+ as a normalization channel. No significant excess of D0→e±μ∓ candidates over the expected background is seen, and a limit is set on the branching fraction, B(D0→e±μ∓)<1.3×10−8, at 90% confidence level. This is an order of magnitude lower than the previous limit and it further constrains the parameter space in some leptoquark models and in supersymmetric models with R-parity violation

First observation of the decay D0→K−π+μ+μ− in the ρ0–ω region of the dimuon mass spectrum

AbstractA study of the decay D0→K−π+μ+μ− is performed using data collected by the LHCb detector in proton–proton collisions at a centre-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 2.0 fb−1. Decay candidates with muon pairs that have an invariant mass in the range 675–875 MeV/c2 are considered. This region is dominated by the ρ0 and ω resonances. The branching fraction in this range is measured to beB(D0→K−π+μ+μ−)=(4.17±0.12(stat)±0.40(syst))×10−6. This is the first observation of the decay D0→K−π+μ+μ−. Its branching fraction is consistent with the value expected in the Standard Model

First observation of the rare B

The $B^{+}\to D^{+} K^{+} \pi^{-}$ decay is observed in a data sample corresponding to $3.0\,{\rm fb}^{-1}$ of $pp$ collision data recorded by the LHCb experiment during 2011 and 2012. The signal significance is $8\,\sigma$ and the branching fraction is measured to be ${\cal B}\left(B^{+}\to D^{+} K^{+} \pi^{-}\right) = (5.31 \pm 0.90 \pm 0.48 \pm 0.35)\times 10^{-6}$, where the uncertainties are statistical, systematic and due to the normalisation mode $B^{+}\to D^{-} K^{+} \pi^{+}$, respectively. The Dalitz plot appears to be dominated by broad structures. Angular distributions are exploited to search for quasi-two-body contributions from $B^{+}\to D^{*}_{2}(2460)^{0}K^{+}$ and $B^{+}\to D^{+} K^{*}(892)^{0}$ decays. No significant signals are observed and upper limits are set on their branching fractions.Comment: 19 pages, 4 figures, submitted to Phys. Rev. D. (R). All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-054.html. Updated following erratum: 10.1103/PhysRevD.93.11990

Model-independent measurement of mixing parameters in D-0 -> K-S(0)pi(+)pi(-) decays

The first model-independent measurement of the charm mixing parameters in the decay D0 → KS 0π+π− is reported, using a sample of pp collision data recorded by the LHCb experiment, corresponding to an integrated luminosity of 1.0 fb−1 at a centre-of-mass energy of 7 TeV. The measured values are, (Formula presented.) where the first uncertainties are statistical and include small contributions due to the external input for the strong phase measured by the CLEO collaboration, and the second uncertainties are systematic

Differential branching fraction and angular moments analysis of the decay B-0 -> K+pi(-)mu(+)mu(-) in the K-0,K-2*(1431:)(0) region

Measurements of the differential branching fraction and angular moments of the decay B-0 -> K+pi(-)mu(+)mu(-) in the K+pi(-) invariant mass range 1330 <m(K+pi(-)) < 1530 MeV/c(2) are presented. Proton-proton collision data are used, corresponding to an integrated luminosity of 3 fb(-1) collected by the LHCb experiment. Differential branching fraction measurements are reported in five bins of the invariant mass squared of the dimuon system, q(2), between 0.1 and 8.0 GeV2/c(4). For the first time, an angular analysis sensitive to the S-, P- and D-wave contributions of this rare decay is performed. The set of 40 normalised angular moments describing the decay is presented for the q(2) range 1.1-6.0 GeV2/c(4)