Explore the vast range of titles available.

A search for the charmless B0s→η′ϕ decay is performed using pp collision data collected by the LHCb experiment at centre-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3 fb−1. No signal is observed and upper limits on the B0s→η′ϕ branching fraction are set to 0.82×10−6 at 90% and 1.01×10−6 at 95% confidence level.

An amplitude analysis of the decay Λ0b→D0pπ− is performed in the part of the phase space containing resonances in the D0p channel. The study is based on a data sample corresponding to an integrated luminosity of 3.0 fb−1 of pp collisions recorded by the LHCb experiment. The spectrum of excited Λ+c states that decay into D0p is studied. The masses, widths and quantum numbers of the Λc(2880)+ and Λc(2940)+ resonances are measured. The constraints on the spin and parity for the Λc(2940)+ state are obtained for the first time. A near-threshold enhancement in the D0p amplitude is investigated and found to be consistent with a new resonance, denoted the Λc(2860)+, of spin 3/2 and positive parity.

The suppressed decay Λ0b→pπ−μ+μ−, excluding the J/ψ and ψ(2S)→μ+μ− resonances, is observed for the first time with a significance of 5.5 standard deviations. The analysis is performed with proton-proton collision data corresponding to an integrated luminosity of 3fb−1 collected with the LHCb experiment. The Λ0b→pπ−μ+μ− branching fraction is measured relative to the Λ0b→J/ψ(→μ+μ−)pπ− branching fraction givingB(Λ0b→pπ−μ+μ−)B(Λ0b→J/ψ(→μ+μ−)pπ−)=0.044±0.012±0.007,where the first uncertainty is statistical and the second is systematic. This is the first observation of a b→d transition in a baryonic decay.

A measurement of the cross-section for W→eν production in pp collisions is presented using data corresponding to an integrated luminosity of 2fb−1 collected by the LHCb experiment at a centre-of-mass energy of s√=8TeV. The electrons are required to have more than 20GeV of transverse momentum and to lie between 2.00 and 4.25 in pseudorapidity. The inclusive W production cross-sections, where the W decays to eν, are measured to be _(W)⁺ e⁺ₑ&=1124.4 2.1 21.5 11.2 13.0 pb, _(W)⁻ e⁻ₑ&= 809.0 1.9 18.1 7.0 09.4 pb, where the first uncertainties are statistical, the second are systematic, the third are due to the knowledge of the LHC beam energy and the fourth are due to the luminosity determination. Differential cross-sections as a function of the electron pseudorapidity are measured. The W+/W− cross-section ratio and production charge asymmetry are also reported. Results are compared with theoretical predictions at next-to-next-to-leading order in perturbative quantum chromodynamics. Finally, in a precise test of lepton universality, the ratio of W boson branching fractions is determined to be B(W e)/B(W )=1.020 0.002 0.019, where the first uncertainty is statistical and the second is systematic.

Associated production of bottomonia and open charm hadrons inppcollisions at√s̅=7and8 TeV is observed using data corresponding to an integrated luminosity of 3 fb⁻¹accumulated with the LHCb detector. The observation of five combinations,Υ(1S)D⁰ ,Υ(2S)D⁰ ,Υ(1S)D⁺ ,Υ(2S)D⁺andΥ(1S)D⁺_(s) , is reported. Production cross-sections are measured forΥ(1S)D⁰andΥ(1S)D⁺pairs in the forward region. The measured cross-sections and the differential distributions indicate the dominance of double parton scattering as the main production mechanism. This allows a precise measurement of the effective cross-section for double parton scattering.

A model-dependent amplitude analysis of the decay B0→D(K0Sπ+π−)K∗0 is performed using proton-proton collision data corresponding to an integrated luminosity of 3.0fb−1, recorded at s√=7 and 8TeV by the LHCb experiment. The CP violation observables x± and y±, sensitive to the CKM angle γ, are measured to bex−=−0.15±0.14±0.03±0.01,y−=0.25±0.15±0.06±0.01,x+=0.05±0.24±0.04±0.01,y+=−0.65+0.24−0.23±0.08±0.01,where the first uncertainties are statistical, the second systematic and the third arise from the uncertainty on the D→K0Sπ+π− amplitude model. These are the most precise measurements of these observables. They correspond to γ=(80+21−22)∘ and rB0=0.39±0.13, where rB0 is the magnitude of the ratio of the suppressed and favoured B0→DK+π− decay amplitudes, in a Kπ mass region of ±50MeV around the K∗(892)0 mass and for an absolute value of the cosine of the K∗0 decay angle larger than 0.4.

The first model-independent measurement of the charm mixing parameters in the decayD⁰ → K_(S) π⁺ π⁻is reported, using a sample ofppcollision data recorded by the LHCb experiment, corresponding to an integrated luminosity of 1.0 fb ⁻¹at a centre-of-mass energy of 7 TeV. The measured values are eqnarray* x &=& (+0.86 0.53 0.17) 10⁻2, y &=& (+0.03 0.46 0.13) 10⁻2, eqnarray* 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. The results are consistent with the current world averages.

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 \\[ (pp ccX) = 2940 3 180 160\\, \\] where the uncertainties are due to statistical, systematic and fragmentation fraction uncertainties, respectively.

TheB_(s)⁰ → J/ψ φ φdecay is observed inppcollision data corresponding to an integrated luminosity of 3 fb ⁻¹recorded 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 theB_(s)⁰meson is measured to be5367.08 ± 0.38 ± 0.15MeV/c ² . The branching fraction ratio𝓑(B_(s)⁰ → J/ψ φ φ)/𝓑(B_(s)⁰ → J/ψ φ)is measured to be0.0115 ± 0.0012 ^(+0.0005)_(-0.0009) . In both cases, the first uncertainty is statistical and the second is systematic. No evidence for non-resonantB_(s)⁰ → J/ψ φ K⁺ K⁻orB_(s)⁰ → J/ψ K⁺ K⁻ K⁺ K⁻decays is found.