321 research outputs found

    Study of the BΛc+ΛˉcKB^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} decay

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    The decay BΛc+ΛˉcKB^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} is studied in proton-proton collisions at a center-of-mass energy of s=13\sqrt{s}=13 TeV using data corresponding to an integrated luminosity of 5 fb1\mathrm{fb}^{-1} collected by the LHCb experiment. In the Λc+K\Lambda_{c}^+ K^{-} system, the Ξc(2930)0\Xi_{c}(2930)^{0} state observed at the BaBar and Belle experiments is resolved into two narrower states, Ξc(2923)0\Xi_{c}(2923)^{0} and Ξc(2939)0\Xi_{c}(2939)^{0}, whose masses and widths are measured to be m(Ξc(2923)0)=2924.5±0.4±1.1MeV,m(Ξc(2939)0)=2938.5±0.9±2.3MeV,Γ(Ξc(2923)0)=0004.8±0.9±1.5MeV,Γ(Ξc(2939)0)=0011.0±1.9±7.5MeV, m(\Xi_{c}(2923)^{0}) = 2924.5 \pm 0.4 \pm 1.1 \,\mathrm{MeV}, \\ m(\Xi_{c}(2939)^{0}) = 2938.5 \pm 0.9 \pm 2.3 \,\mathrm{MeV}, \\ \Gamma(\Xi_{c}(2923)^{0}) = \phantom{000}4.8 \pm 0.9 \pm 1.5 \,\mathrm{MeV},\\ \Gamma(\Xi_{c}(2939)^{0}) = \phantom{00}11.0 \pm 1.9 \pm 7.5 \,\mathrm{MeV}, where the first uncertainties are statistical and the second systematic. The results are consistent with a previous LHCb measurement using a prompt Λc+K\Lambda_{c}^{+} K^{-} sample. Evidence of a new Ξc(2880)0\Xi_{c}(2880)^{0} state is found with a local significance of 3.8σ3.8\,\sigma, whose mass and width are measured to be 2881.8±3.1±8.5MeV2881.8 \pm 3.1 \pm 8.5\,\mathrm{MeV} and 12.4±5.3±5.8MeV12.4 \pm 5.3 \pm 5.8 \,\mathrm{MeV}, respectively. In addition, evidence of a new decay mode Ξc(2790)0Λc+K\Xi_{c}(2790)^{0} \to \Lambda_{c}^{+} K^{-} is found with a significance of 3.7σ3.7\,\sigma. The relative branching fraction of BΛc+ΛˉcKB^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} with respect to the BD+DKB^{-} \to D^{+} D^{-} K^{-} decay is measured to be 2.36±0.11±0.22±0.252.36 \pm 0.11 \pm 0.22 \pm 0.25, where the first uncertainty is statistical, the second systematic and the third originates from the branching fractions of charm hadron decays.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-028.html (LHCb public pages

    Measurement of the ratios of branching fractions R(D)\mathcal{R}(D^{*}) and R(D0)\mathcal{R}(D^{0})

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    The ratios of branching fractions R(D)B(BˉDτνˉτ)/B(BˉDμνˉμ)\mathcal{R}(D^{*})\equiv\mathcal{B}(\bar{B}\to D^{*}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(\bar{B}\to D^{*}\mu^{-}\bar{\nu}_{\mu}) and R(D0)B(BD0τνˉτ)/B(BD0μνˉμ)\mathcal{R}(D^{0})\equiv\mathcal{B}(B^{-}\to D^{0}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(B^{-}\to D^{0}\mu^{-}\bar{\nu}_{\mu}) are measured, assuming isospin symmetry, using a sample of proton-proton collision data corresponding to 3.0 fb1{ }^{-1} of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode τμντνˉμ\tau^{-}\to\mu^{-}\nu_{\tau}\bar{\nu}_{\mu}. The measured values are R(D)=0.281±0.018±0.024\mathcal{R}(D^{*})=0.281\pm0.018\pm0.024 and R(D0)=0.441±0.060±0.066\mathcal{R}(D^{0})=0.441\pm0.060\pm0.066, where the first uncertainty is statistical and the second is systematic. The correlation between these measurements is ρ=0.43\rho=-0.43. Results are consistent with the current average of these quantities and are at a combined 1.9 standard deviations from the predictions based on lepton flavor universality in the Standard Model.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-039.html (LHCb public pages

    Common genetic variants in the CLDN2 and PRSS1-PRSS2 loci alter risk for alcohol-related and sporadic pancreatitis

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    Pancreatitis is a complex, progressively destructive inflammatory disorder. Alcohol was long thought to be the primary causative agent, but genetic contributions have been of interest since the discovery that rarePRSS1,CFTR, andSPINK1variants were associated with pancreatitis risk. We now report two significant genome-wide associations identified and replicated atPRSS1-PRSS2(1×10-12) and x-linkedCLDN2(p < 1×10-21) through a two-stage genome-wide study (Stage 1, 676 cases and 4507 controls; Stage 2, 910 cases and 4170 controls). ThePRSS1variant affects susceptibility by altering expression of the primary trypsinogen gene. TheCLDN2risk allele is associated with atypical localization of claudin-2 in pancreatic acinar cells. The homozygous (or hemizygous male)CLDN2genotype confers the greatest risk, and its alleles interact with alcohol consumption to amplify risk. These results could partially explain the high frequency of alcohol-related pancreatitis in men – male hemizygous frequency is 0.26, female homozygote is 0.07

    Pulmonary and Pleural Manifestations of Extrathoracic Malignancies

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    Measurement of prompt D+D^+ and Ds+D^+_{s} production in pPbp\mathrm{Pb} collisions at sNN=5.02\sqrt {s_{\mathrm{NN}}}=5.02\,TeV

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    International audienceThe production of prompt D+D^+ and Ds+D^+_{s} mesons is studied in proton-lead collisions at a centre-of-mass energy of sNN=5.02\sqrt {s_{\mathrm{NN}}}=5.02\,TeV. The data sample corresponding to an integrated luminosity of (1.58±0.02)nb1(1.58\pm0.02)\mathrm{nb}^{-1} is collected by the LHCb experiment at the LHC. The differential production cross-sections are measured using D+D^+ and Ds+D^+_{s} candidates with transverse momentum in the range of 0<pT<14GeV/c0<p_{\mathrm{T}} <14\,\mathrm{GeV}/c and rapidities in the ranges of 1.5<y<4.01.5<y^*<4.0 and 5.0<y<2.5-5.0<y^*<-2.5 in the nucleon-nucleon centre-of-mass system. For both particles, the nuclear modification factor and the forward-backward production ratio are determined. These results are compared with theoretical models that include initial-state nuclear effects. In addition, measurements of the cross-section ratios between D+D^+, Ds+D^+_{s} and D0D^0 mesons are presented, providing a baseline for studying the charm hadronization in lead-lead collisions at LHC energies

    Improved measurement of CPCP violation parameters in Bs0J/ψK+KB_s^0\to J/\psi K^+K^- decays in the vicinity of the ϕ(1020)\phi(1020) resonance

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    The decay-time-dependent CPCP asymmetry in Bs0J/ψ(μ+μ)K+KB_s^0\to J/\psi(\to \mu^+\mu^-) K^+ K^- decays is measured using proton-proton collision data, corresponding to an integrated luminosity of 6fb16 {\rm fb}^{-1}, collected with the LHCb detector at a center-of-mass energy of 13 TeV. Using a sample of approximately 349 000 Bs0B_s^0 signal decays with an invariant K+KK^+ K^- mass in the vicinity of the ϕ(1020)\phi(1020) resonance, the CPCP-violating phase ϕs\phi_s is measured, along with the difference in decay widths of the light and heavy mass eigenstates of the Bs0B_s^0-Bs0\overline{B}_s^0 system, ΔΓs\Delta\Gamma_s, and the difference of the average Bs0B_s^0 and B0B^0 meson decay widths, ΓsΓd\Gamma_s-\Gamma_d. The values obtained are ϕs=0.039±0.022±0.006\phi_s = -0.039 \pm 0.022 \pm 0.006 rad, ΔΓs=0.0845±0.0044±0.0024 ps1\Delta\Gamma_s = 0.0845 \pm 0.0044 \pm 0.0024 ~{\rm ps}^{-1} and ΓsΓd=0.0560.0015+0.0013±0.0014 ps1\Gamma_s-\Gamma_d = -0.056^{\:+\:0.0013}_{\:-\:0.0015} \pm 0.0014 ~{\rm ps}^{-1}, where the first uncertainty is statistical and the second systematic. These are the most precise single measurements to date and are consistent with expectations based on the Standard Model and with the previous LHCb analyses of this decay. These results are combined with previous independent LHCb measurements. The phase ϕs\phi_s is also measured independently for each polarization state of the K+KK^+K^- system and shows no evidence for polarization dependence.The decay-time-dependent CPCP asymmetry in Bs0J/ψ(μ+μ)K+KB^0_s\to J/\psi(\to \mu^{+}\mu^{-}) K^{+}K^{-} decays is measured using proton-proton collision data, corresponding to an integrated luminosity of 6 fb1fb^{-1}, collected with the LHCb detector at a center-of-mass energy of 13 TeV. Using a sample of approximately 349 000 Bs0B^{0}_{s} signal decays with an invariant K+KK^{+}K^{-} mass in the vicinity of the ϕ(1020)\phi(1020) resonance, the CPCP-violating phase ϕs\phi_s is measured, along with the difference in decay widths of the light and heavy mass eigenstates of the Bs0B^0_s-Bˉs0\bar{B}^0_s system, ΔΓs\Delta\Gamma_s, and the difference of the average Bs0B^0_s and B0B^0 meson decay widths, ΓsΓd\Gamma_s-\Gamma_d. The values obtained are ϕs= 0.039±0.022±0.006\phi_s = \ -0.039 \pm 0.022 \pm 0.006 rad, ΔΓs=0.0845±0.0044±0.0024\Delta\Gamma_s = 0.0845 \pm 0.0044 \pm 0.0024 ps1^{-1} and ΓsΓd=0.00560.0015+0.0013±0.0014\Gamma_s-\Gamma_d = -0.0056 ^{+ 0.0013}_{-0.0015} \pm 0.0014 ps1^{-1}, where the first uncertainty is statistical and the second systematic. These are the most precise single measurements to date and are consistent with expectations based on the Standard Model and with the previous LHCb analyses of this decay. These results are combined with previous independent LHCb measurements. The phase ϕs\phi_s is also measured independently for each polarization state of the K+KK^{+}K^{-} system and shows no evidence for polarization dependence

    Precision measurement of CP\it{CP} violation in the penguin-mediated decay Bs0ϕϕB_s^{0}\rightarrow\phi\phi

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    International audienceA flavor-tagged time-dependent angular analysis of the decay Bs0ϕϕB_s^{0}\rightarrow\phi\phi is performed using pppp collision data collected by the LHCb experiment at s=13\sqrt{s}=13 TeV, the center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 6 fb^{-1}. The CP\it{CP}-violating phase and direct CP\it{CP}-violation parameter are measured to be ϕssˉs=0.042±0.075±0.009\phi_{s\bar{s}s} = -0.042 \pm 0.075 \pm 0.009 rad and λ=1.004±0.030±0.009|\lambda|=1.004\pm 0.030 \pm 0.009 , respectively, assuming the same values for all polarization states of the ϕϕ\phi\phi system. In these results, the first uncertainties are statistical and the second systematic. These parameters are also determined separately for each polarization state, showing no evidence for polarization dependence. The results are combined with previous LHCb measurements using pppp collisions at center-of-mass energies of 7 and 8 TeV, yielding ϕssˉs=0.074±0.069\phi_{s\bar{s}s} = -0.074 \pm 0.069 rad and λ=1.009±0.030|\lambda|=1.009 \pm 0.030. This is the most precise study of time-dependent CP\it{CP} violation in a penguin-dominated BB meson decay. The results are consistent with CP\it{CP} symmetry and with the Standard Model predictions
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