ORCID Profile
0000-0002-2589-240X
Current Organisations
Centre de physique des particules de Marseille
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CNRS
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Publisher: Springer Science and Business Media LLC
Date: 17-10-2023
Publisher: Springer Science and Business Media LLC
Date: 02-01-2202
DOI: 10.1140/EPJC/S10052-023-11759-6
Abstract: The very rare $${{D} ^*} (2007)^0\\!\\rightarrow {\\mu ^+\\mu ^-} $$ D ∗ ( 2007 ) 0 → μ + μ - decay is searched for by analysing $${{{B} ^-}} \\!\\rightarrow {{\\pi } ^-} {\\mu ^+\\mu ^-} $$ B - → π - μ + μ - decays. The analysis uses a s le of beauty mesons produced in proton–proton collisions collected with the LHCb detector between 2011 and 2018, corresponding to an integrated luminosity of 9 $$\\text {\\,fb} ^{-1}$$ \\,fb - 1 . The signal signature corresponds to simultaneous peaks in the $${\\mu ^+\\mu ^-} $$ μ + μ - and $${{\\pi } ^-} {\\mu ^+\\mu ^-} $$ π - μ + μ - invariant masses. No evidence for an excess of events over background is observed and an upper limit is set on the branching fraction of the decay at $$\\mathcal{B}({{D} ^*} (2007)^0\\!\\rightarrow {\\mu ^+\\mu ^-} ) 2.6\\times 10^{-8}$$ B ( D ∗ ( 2007 ) 0 → μ + μ - ) 2.6 × 10 - 8 at $$90\\%$$ 90 % confidence level. This is the first limit on the branching fraction of $${{D} ^*} (2007)^0\\!\\rightarrow {\\mu ^+\\mu ^-} $$ D ∗ ( 2007 ) 0 → μ + μ - decays and the most stringent limit on $${{D} ^*} (2007)^0$$ D ∗ ( 2007 ) 0 decays to leptonic final states. The analysis is the first search for a rare charm-meson decay exploiting production via beauty decays.
Publisher: American Physical Society (APS)
Date: 08-03-2017
Publisher: Springer Science and Business Media LLC
Date: 17-07-2023
DOI: 10.1140/EPJC/S10052-023-11608-6
Abstract: The measurement of charmonium states produced in proton-neon ( $$p\\text {Ne}$$ p Ne ) collisions by the LHCb experiment in its fixed-target configuration is presented. The production of $${{J} \\hspace{-1.66656pt}/\\hspace{-1.111pt}\\psi }$$ J / ψ and $$\\psi {(2S)}$$ ψ ( 2 S ) mesons is studied with a beam of 2.5 $$\\mathrm{\\,Te\\hspace{-1.00006pt}V}$$ Te V protons colliding on gaseous neon targets at rest, corresponding to a nucleon-nucleon centre-of-mass energy $$\\sqrt{s_{\\scriptscriptstyle \\text {NN}}} =68.5\\mathrm{\\,Ge\\hspace{-1.00006pt}V} $$ s NN = 68.5 Ge V . The data s le corresponds to an integrated luminosity of $$21.7\\pm 1.4 $$ 21.7 ± 1.4 nb $$^{-1}$$ - 1 . The $${{J} \\hspace{-1.66656pt}/\\hspace{-1.111pt}\\psi }$$ J / ψ and $$\\psi {(2S)}$$ ψ ( 2 S ) hadrons are reconstructed in $$\\mu ^+$$ μ + $$\\mu ^-$$ μ - final states. The $${{J} \\hspace{-1.66656pt}/\\hspace{-1.111pt}\\psi }$$ J / ψ production cross-section per target nucleon in the centre-of-mass rapidity range $$y^\\star \\in [-2.29, 0]$$ y ⋆ ∈ [ - 2.29 , 0 ] is found to be $$506 \\pm 8 \\pm 46 \\text { nb/nucleon}$$ 506 ± 8 ± 46 nb/nucleon . The ratio of $${{J} \\hspace{-1.66656pt}/\\hspace{-1.111pt}\\psi }$$ J / ψ and $$D^0$$ D 0 cross-sections is evaluated to $$(1.06 \\pm 0.02 \\pm 0.09)\\%$$ ( 1.06 ± 0.02 ± 0.09 ) % . The $$\\psi {(2S)}$$ ψ ( 2 S ) to $${{J} \\hspace{-1.66656pt}/\\hspace{-1.111pt}\\psi }$$ J / ψ relative production rate is found to be $$(1.67 \\pm 0.27\\pm 0.10)\\%$$ ( 1.67 ± 0.27 ± 0.10 ) % in good agreement with other measurements involving beam and target nuclei of similar sizes.
Publisher: Springer Science and Business Media LLC
Date: 30-01-2017
DOI: 10.1038/NPHYS4021
Publisher: American Physical Society (APS)
Date: 29-08-2023
Publisher: American Physical Society (APS)
Date: 29-08-2023
Publisher: Springer Science and Business Media LLC
Date: 29-06-2023
DOI: 10.1140/EPJC/S10052-023-11560-5
Abstract: The first study of $$C\\!P$$ C P violation in the decay mode $${{B} ^\\pm } \\rightarrow [{{K} ^+} {{K} ^-} {{\\uppi } ^+} {{\\uppi } ^-} ]_{D} h^\\pm $$ B ± → [ K + K - π + π - ] D h ± , with $$h=K,\\pi $$ h = K , π , is presented, exploiting a data s le of proton–proton collisions collected by the LHCb experiment that corresponds to an integrated luminosity of $$9\\text {\\,fb} ^{-1} $$ 9 \\,fb - 1 . The analysis is performed in bins of phase space, which are optimised for sensitivity to local $$C\\!P$$ C P asymmetries. $$C\\!P$$ C P -violating observables that are sensitive to the angle $$\\gamma $$ γ of the Unitarity Triangle are determined. The analysis requires external information on charm-decay parameters, which are currently taken from an litude analysis of LHCb data, but can be updated in the future when direct measurements become available. Measurements are also performed of phase-space integrated observables for $${{B} ^\\pm } \\rightarrow [{{K} ^+} {{K} ^-} {{\\uppi } ^+} {{\\uppi } ^-} ]_{D} h^\\pm $$ B ± → [ K + K - π + π - ] D h ± and $${{B} ^\\pm } \\rightarrow [{{\\uppi } ^+} {{\\uppi } ^-} {{\\uppi } ^+} {{\\uppi } ^-} ]_{D} h^\\pm $$ B ± → [ π + π - π + π - ] D h ± decays.
Publisher: American Physical Society (APS)
Date: 06-09-2023
Publisher: American Physical Society (APS)
Date: 26-09-2023
Publisher: American Physical Society (APS)
Date: 06-09-2023
Publisher: Springer Science and Business Media LLC
Date: 18-04-2023
Abstract: Searches for CP violation in the decays $$ {D}_{(s)}^{+}\\to \\eta {\\pi}^{+} $$ D s + → η π + and $$ {D}_{(s)}^{+}\\to {\\eta}^{\\prime }{\\pi}^{+} $$ D s + → η ′ π + are performed using pp collision data corresponding to 6 fb − 1 of integrated luminosity collected by the LHCb experiment. The calibration channels $$ {D}_{(s)}^{+}\\to \\phi {\\pi}^{+} $$ D s + → ϕ π + are used to remove production and detection asymmetries. The resulting CP -violating asymmetries are $$ {\\displaystyle \\begin{array}{l}{\\mathcal{A}}^{CP}=\\left({D}^{+}\\to \\eta {\\pi}^{+}\\right)=\\left(0.34\\pm 0.66\\pm 0.16\\pm 0.05\\right)\\%,\\\\ {}{\\mathcal{A}}^{CP}=\\left({D}_s^{+}\\to \\eta {\\pi}^{+}\\right)=\\left(0.32\\pm 0.51\\pm 0.12\\right)\\%,\\\\ {}\\begin{array}{l}{\\mathcal{A}}^{CP}=\\left({D}^{+}\\to {\\eta}^{\\prime }{\\pi}^{+}\\right)=\\left(0.49\\pm 0.18\\pm 0.06\\pm 0.05\\right)\\%,\\\\ {}{\\mathcal{A}}^{CP}=\\left({D}_s^{+}\\to {\\eta}^{\\prime }{\\pi}^{+}\\right)=\\left(0.01\\pm 0.12\\pm 0.08\\right)\\%,\\end{array}\\end{array}} $$ A CP = D + → η π + = 0.34 ± 0.66 ± 0.16 ± 0.05 % , A CP = D s + → η π + = 0.32 ± 0.51 ± 0.12 % , A CP = D + → η ′ π + = 0.49 ± 0.18 ± 0.06 ± 0.05 % , A CP = D s + → η ′ π + = 0.01 ± 0.12 ± 0.08 % , where the first uncertainty is statistical, the second is systematic and the third, relevant for the D + channels, is due to the uncertainty on $$ {\\mathcal{A}}^{CP}=\\left({D}^{+}\\to \\phi {\\pi}^{+}\\right) $$ A CP = D + → ϕ π + . These measurements, currently the most precise for three of the four channels considered, are consistent with the absence of CP violation. A combination of these results with previous LHCb measurements is presented.
Publisher: American Physical Society (APS)
Date: 26-09-2023
Publisher: American Physical Society (APS)
Date: 14-07-2023
Publisher: American Physical Society (APS)
Date: 18-09-2023
Publisher: Springer Science and Business Media LLC
Date: 07-07-2023
Abstract: The production cross-sections of Υ mesons, namely Υ(1 S ), Υ(2 S ) and Υ(3 S ), in pp collisions at $$ \\sqrt{s} $$ s = 5 TeV are measured with a data s le corresponding to an integrated luminosity of 9 . 13 ± 0 . 18 pb − 1 collected by the LHCb detector. The Υ mesons are reconstructed in the decay mode Υ → μ + μ − . Double differential cross-sections times branching fractions, as functions of the transverse momentum p T and the rapidity y of the Υ mesons, are measured in the range p T 20 GeV/ c and 2 . 0 y 4 . 5. The results integrated over these p T and y ranges are $$ \\sigma \\left(\\textrm{Y}(1S)\\right)\\times \\mathcal{B}\\left(\\textrm{Y}(1S)\\to {\\mu}^{+}{\\mu}^{-}\\right)=2101\\pm 33\\pm 83\\ \\textrm{pb}, $$$$ \\sigma \\left(\\textrm{Y}(2S)\\right)\\times \\mathcal{B}\\left(\\textrm{Y}(2S)\\to {\\mu}^{+}{\\mu}^{-}\\right)=526\\pm 20\\pm 21\\ \\textrm{pb}, $$$$ \\sigma \\left(\\textrm{Y}(3S)\\right)\\times \\mathcal{B}\\left(\\textrm{Y}(3S)\\to {\\mu}^{+}{\\mu}^{-}\\right)=242\\pm 16\\pm 10\\ \\textrm{pb}, $$ σ Υ 1 S × B Υ 1 S → μ + μ − = 2101 ± 33 ± 83 pb , σ Υ 2 S × B Υ 2 S → μ + μ − = 526 ± 20 ± 21 pb , σ Υ 3 S × B Υ 3 S → μ + μ − = 242 ± 16 ± 10 pb , where the first uncertainties are statistical and the second are systematic. The ratios of cross-sections between measurements of two different Υ states and between measurements at different centre-of-mass energies are determined. The nuclear modification factor of Υ(1 S ) at $$ \\sqrt{s} $$ s = 5 TeV is updated as well using the directly measured cross-section results from this analysis.
Publisher: American Physical Society (APS)
Date: 23-03-2023
Publisher: Springer Science and Business Media LLC
Date: 03-2021
DOI: 10.1140/EPJC/S10052-020-8156-7
Abstract: This paper reports world averages of measurements of b -hadron, c -hadron, and $$\\tau $$ τ -lepton properties obtained by the Heavy Flavour Averaging Group using results available through September 2018. In rare cases, significant results obtained several months later are also used. For the averaging, common input parameters used in the various analyses are adjusted (rescaled) to common values, and known correlations are taken into account. The averages include branching fractions, lifetimes, neutral meson mixing parameters, $$C\\!P$$ C P violation parameters, parameters of semileptonic decays, and Cabibbo–Kobayashi–Maskawa matrix elements.
Publisher: American Physical Society (APS)
Date: 28-07-2023
Publisher: Springer Science and Business Media LLC
Date: 20-10-2023
Publisher: American Physical Society (APS)
Date: 28-07-0154
Publisher: American Physical Society (APS)
Date: 23-10-2023
Publisher: American Physical Society (APS)
Date: 23-10-2023
Publisher: Springer Science and Business Media LLC
Date: 17-07-2023
DOI: 10.1140/EPJC/S10052-023-11634-4
Abstract: Using a proton–proton collision data s le collected by the LHCb detector and corresponding to an integrated luminosity of $$5.7~\\text {fb}^{-1}$$ 5.7 fb - 1 , the lifetime of the light $${{B} ^0_{s}} $$ B s 0 mass eigenstate, $$\\tau _{L}$$ τ L , is measured using the $$B^0_s \\rightarrow J/\\psi \\eta $$ B s 0 → J / ψ η decay mode to be $$\\begin{aligned} \\tau _{\\text {L}} = 1.445 \\pm 0.016 \\text {(stat)} \\pm 0.008 \\text {(syst)} \\,\\text {ps}. \\end{aligned}$$ τ L = 1.445 ± 0.016 (stat) ± 0.008 (syst) ps . A combination of this result with a previous LHCb analysis using an independent dataset corresponding to 3 fb $$^{-1}$$ - 1 of integrated luminosity gives $$\\begin{aligned} \\tau _{\\text {L}} = 1.452 \\pm 0.014 \\pm 0.007 \\pm 0.002 \\,\\text {ps}, \\end{aligned}$$ τ L = 1.452 ± 0.014 ± 0.007 ± 0.002 ps , where the first uncertainty is statistical, the second due to the uncorrelated part of the systematic uncertainty and the third due to the correlated part of the systematic uncertainty.
Publisher: American Physical Society (APS)
Date: 14-08-2023
Publisher: American Physical Society (APS)
Date: 17-08-2023
Publisher: American Physical Society (APS)
Date: 10-08-2023
Publisher: Springer Science and Business Media LLC
Date: 05-06-2023
Abstract: This article presents the first measurement of the differential Z -boson production cross-section in the forward region using proton-lead collisions with the LHCb detector. The dataset was collected at a nucleon-nucleon centre-of-mass energy of $$ \\sqrt{s_{\\textrm{NN}}} $$ s NN = 8 . 16 TeV in 2016, corresponding to an integrated luminosity of 30 . 8 nb − 1 . The forward-backward ratio and the nuclear modification factors are measured together with the differential cross-section as functions of the Z boson rapidity in the centre-of-mass frame, the transverse momentum of the Z boson and a geometric variable ϕ * . The results are in good agreement with the predictions from nuclear parton distribution functions, providing strong constraining power at small Bjorken- x .
Publisher: Elsevier BV
Date: 06-2012
Publisher: Springer Science and Business Media LLC
Date: 28-09-2023
Publisher: Springer Science and Business Media LLC
Date: 17-08-2023
Abstract: The associated production of prompt J/ψ and Υ mesons in pp collisions at a centre-of-mass energy of $$ \\sqrt{s} $$ s = 13 TeV is studied using LHCb data, corresponding to an integrated luminosity of 4 fb − 1 . The measurement is performed for J/ψ ( Υ ) mesons with a transverse momentum p T 10 (30) GeV/ c in the rapidity range 2 . 0 y 4 . 5. In this kinematic range, the cross-section of the associated production of prompt J/ψ and Υ (1 S ) mesons is measured to be 133 ± 22 ± 7 ± 3 pb, with a significance of 7 . 9 σ , and that of prompt J/ψ and Υ (2 S ) mesons to be 76 ± 21 ± 4 ± 7 pb, with a significance of 4 . 9 σ . The first uncertainty is statistical, the second systematic, and the third due to uncertainties on the used branching fractions. This is the first observation of the associated production of J/ψ and Υ (1 S ) in proton-proton collisions. Differential cross-sections are measured as functions of variables that are sensitive to kinematic correlations between the J/ψ and Υ (1 S ) mesons. The effective cross-sections of the associated production of prompt J/ψ and Υ mesons are obtained and found to be compatible with measurements using other particle productions.
Publisher: American Physical Society (APS)
Date: 27-07-2023
Publisher: Springer Science and Business Media LLC
Date: 20-09-2202
Publisher: IOP Publishing
Date: 09-2023
Abstract: A first search for the decay is performed by the LHCb experiment with a data s le of proton-proton collisions, corresponding to an integrated luminosity of 9 fb −1 recorded at centre-of-mass energies of 7, 8, and 13 TeV. Two peaking structures are seen with a local (global) significance of and standard deviations at masses of 6571 and 6694 MeV/ , respectively. Upper limits are set on the baryon production cross-section times the branching fraction relative to that of the decay at centre-of-mass energies of 8 and 13 TeV, in the and in the rapidity and transverse-momentum ranges from 2.0 to 4.5 and 0 to , respectively. Upper limits are presented as a function of the mass and lifetime.
Publisher: American Physical Society (APS)
Date: 14-08-2023
Publisher: Springer Science and Business Media LLC
Date: 10-07-2023
Abstract: The first observation of the $$ {\\Lambda}_b^0\\to {D}_s^{-}p $$ Λ b 0 → D s − p decay is presented using proton-proton collision data collected by the LHCb experiment at a centre-of-mass energy of $$ \\sqrt{s} $$ s = 13 TeV, corresponding to a total integrated luminosity of 6 fb − 1 . Using the $$ {\\Lambda}_b^0\\to {\\Lambda}_c^{+}{\\pi}^{-} $$ Λ b 0 → Λ c + π − decay as the normalisation mode, the branching fraction of the $$ {\\Lambda}_b^0\\to {D}_s^{-}p $$ Λ b 0 → D s − p decay is measured to be $$ \\mathcal{B}\\left({\\Lambda}_b^0\\to {D}_s^{-}p\\right)=\\left(12.6\\pm 0.5\\pm 0.3\\pm 1.2\\right)\\times {10}^{-6} $$ B Λ b 0 → D s − p = 12.6 ± 0.5 ± 0.3 ± 1.2 × 10 − 6 , where the first uncertainty is statistical, the second systematic and the third due to uncertainties in the branching fractions of the $$ {\\Lambda}_b^0\\to {\\Lambda}_c^{+}{\\pi}^{-} $$ Λ b 0 → Λ c + π − , $$ {D}_s^{-}\\to {K}^{-}{K}^{+}{\\pi}^{-} $$ D s − → K − K + π − and $$ {\\Lambda}_c^{+}\\to p{K}^{-}{\\pi}^{+} $$ Λ c + → p K − π + decays.
Publisher: American Physical Society (APS)
Date: 24-07-2023
Publisher: American Physical Society (APS)
Date: 27-07-2023
Publisher: American Physical Society (APS)
Date: 08-08-2023
Publisher: American Physical Society (APS)
Date: 10-10-2023
Publisher: Springer Science and Business Media LLC
Date: 17-07-2023
Abstract: The CKM angle γ is determined from CP -violating observables measured in B ± → D [ K ∓ π ± π ± π ∓ ] h ± , ( h = K, π ) decays, where the measurements are performed in bins of the decay phase-space of the D meson. Using proton-proton collision data collected by the LHCb experiment at centre-of-mass energies of 7 , 8 and 13 TeV, corresponding to a total integrated luminosity of 9 fb − 1 , γ is determined to be $$ \\gamma ={\\left(54.8\\begin{array}{c}+6.0\\\\ {}-5.8\\end{array}\\begin{array}{c}+0.6\\\\ {}-0.6\\end{array}\\begin{array}{c}+6.7\\\\ {}-4.3\\end{array}\\right)}^{\\circ }, $$ γ = 54.8 + 6.0 − 5.8 + 0.6 − 0.6 + 6.7 − 4.3 ∘ , where the first uncertainty is statistical, the second systematic and the third from the external inputs on the coherence factors and strong phases of the D -meson decays.
Publisher: Springer Science and Business Media LLC
Date: 13-05-2015
DOI: 10.1038/NATURE14474
Abstract: The standard model of particle physics describes the fundamental particles and their interactions via the strong, electromagnetic and weak forces. It provides precise predictions for measurable quantities that can be tested experimentally. The probabilities, or branching fractions, of the strange B meson (B(s)(0)) and the B0 meson decaying into two oppositely charged muons (μ+ and μ−) are especially interesting because of their sensitivity to theories that extend the standard model. The standard model predicts that the B(s)(0) →µ+µ− and B(0) →µ+µ− decays are very rare, with about four of the former occurring for every billion mesons produced, and one of the latter occurring for every ten billion B0 mesons. A difference in the observed branching fractions with respect to the predictions of the standard model would provide a direction in which the standard model should be extended. Before the Large Hadron Collider (LHC) at CERN started operating, no evidence for either decay mode had been found. Upper limits on the branching fractions were an order of magnitude above the standard model predictions. The CMS (Compact Muon Solenoid) and LHCb (Large Hadron Collider beauty) collaborations have performed a joint analysis of the data from proton–proton collisions that they collected in 2011 at a centre-of-mass energy of seven teraelectronvolts and in 2012 at eight teraelectronvolts. Here we report the first observation of the B(s)(0) → µ+µ− decay, with a statistical significance exceeding six standard deviations, and the best measurement so far of its branching fraction. Furthermore, we obtained evidence for the B(0) → µ+µ− decay with a statistical significance of three standard deviations. Both measurements are statistically compatible with standard model predictions and allow stringent constraints to be placed on theories beyond the standard model. The LHC experiments will resume taking data in 2015, recording proton–proton collisions at a centre-of-mass energy of 13 teraelectronvolts, which will approximately double the production rates of B(s)(0) and B0 mesons and lead to further improvements in the precision of these crucial tests of the standard model.
Publisher: Springer Science and Business Media LLC
Date: 27-06-2023
DOI: 10.1140/EPJC/S10052-023-11673-X
Abstract: The interpretation of cosmic antiproton flux measurements from space-borne experiments is currently limited by the knowledge of the antiproton production cross-section in collisions between primary cosmic rays and the interstellar medium. Using collisions of protons with an energy of 6.5 $$\\,\\text {Te\\hspace{-1.00006pt}V}$$ Te V incident on helium nuclei at rest in the proximity of the interaction region of the LHCb experiment, the ratio of antiprotons originating from antihyperon decays to prompt production is measured for antiproton momenta between 12 and $$110\\,\\text {Ge\\hspace{-1.00006pt}V\\!/}c $$ 110 Ge V\\!/ c . The dominant antihyperon contribution, namely $${\\overline{\\varLambda }} \\rightarrow {\\overline{{p}}} {{\\pi } ^+} $$ Λ ¯ → p ¯ π + decays from promptly produced $$\\overline{\\varLambda }$$ Λ ¯ particles, is also exclusively measured. The results complement the measurement of prompt antiproton production obtained from the same data s le. At the energy scale of this measurement, the antihyperon contributions to antiproton production are observed to be significantly larger than predictions of commonly used hadronic production models.
Publisher: Springer Science and Business Media LLC
Date: 25-07-2023
DOI: 10.1140/EPJC/S10052-023-11674-W
Abstract: The first measurement of $${{J}/\\psi }$$ J / ψ and $${{D}} ^0$$ D 0 production in PbNe collisions by the LHCb experiment in its fixed-target configuration is reported. The production of $${{J}/\\psi }$$ J / ψ and $${{D}} ^0$$ D 0 mesons is studied with a beam of lead ions with an energy of 2.5 $$\\,\\text {TeV}$$ TeV per nucleon colliding on gaseous neon targets at rest, corresponding to a nucleon-nucleon centre-of-mass energy of $$\\sqrt{s_{\\scriptscriptstyle \\text {NN}}} =68.5\\,\\text {GeV} $$ s NN = 68.5 GeV . The $${{J}/\\psi }$$ J / ψ / $${{D}} ^0$$ D 0 production cross-section ratio is studied as a function of rapidity, transverse momentum and collision centrality. These data are compared with measurements from $$p\\text {Ne}$$ p Ne collisions at the same energy and show no difference in the observed $${{J}/\\psi }$$ J / ψ suppression trend when comparing $$p\\text {Ne}$$ p Ne and PbNe peripheral collisions with PbNe central collisions.
Publisher: Springer Science and Business Media LLC
Date: 26-09-2023
Publisher: Springer Science and Business Media LLC
Date: 13-07-2023
Abstract: The first observation of the $$ {B}_s^0 $$ B s 0 → D ∗+ D ∗ − decay and the measurement of its branching ratio relative to the B 0 → D ∗+ D ∗ − decay are presented. The data s le used corresponds to an integrated luminosity of 9 fb − 1 of proton-proton collisions recorded by the LHCb experiment at centre-of-mass energies of 7, 8 and 13 TeV between 2011 and 2018. The decay is observed with more than 10 standard deviations and the time-integrated ratio of branching fractions is determined to be $$ \\frac{\\mathcal{B}\\left({B}_s^0\\to {D}^{\\ast +}{D}^{\\ast -}\\right)}{\\mathcal{B}\\left({B}^0\\to {D}^{\\ast +}{D}^{\\ast -}\\right)}=0.269\\pm 0.032\\pm 0.011\\pm 0.008, $$ B B s 0 → D ∗ + D ∗ − B B 0 → D ∗ + D ∗ − = 0.269 ± 0.032 ± 0.011 ± 0.008 , where the first uncertainty is statistical, the second systematic and the third due to the uncertainty of the fragmentation fraction ratio f s /f d . The $$ {B}_s^0 $$ B s 0 → D *+ D * − branching fraction is calculated to be $$ \\mathcal{B}\\left({B}_s^0\\to {D}^{\\ast +}{D}^{\\ast -}\\right)=\\left(2.15\\pm 0.26\\pm 0.09\\pm 0.06\\pm 0.16\\right)\\times {10}^{-4}, $$ B B s 0 → D ∗ + D ∗ − = 2.15 ± 0.26 ± 0.09 ± 0.06 ± 0.16 × 10 − 4 , where the fourth uncertainty is due to the B 0 → D * + D *− branching fraction. These results are calculated using the average $$ {B}_s^0 $$ B s 0 meson lifetime in simulation. Correction factors are reported for scenarios where either a purely heavy or a purely light $$ {B}_s^0 $$ B s 0 eigenstate is considered.
Publisher: Springer Science and Business Media LLC
Date: 27-06-2023
DOI: 10.1140/EPJC/S10052-023-11641-5
Abstract: A measurement of $${{D}} ^0$$ D 0 meson production by the LHCb experiment in its fixed-target configuration is presented. The production of $${{D}} ^0$$ D 0 mesons is studied with a beam of 2.5 $$\\,\\text {Te\\hspace{-1.00006pt}V}$$ Te V protons colliding on a gaseous neon target at rest, corresponding to a nucleon–nucleon centre-of-mass energy of $$\\sqrt{s_{\\scriptscriptstyle \\text {NN}}} = 68.5\\,\\,\\text {Ge\\hspace{-1.00006pt}V} $$ s NN = 68.5 Ge V . The sum of the $${{D}} ^0$$ D 0 and $${\\hspace{0.0pt}\\overline{\\hspace{0.0pt}{D}}} {}^0$$ D ¯ 0 production cross-section in $$p\\text {Ne}$$ p Ne collisions in the centre-of-mass rapidity range $$y^{\\star }\\in [-2.29, 0]$$ y ⋆ ∈ [ - 2.29 , 0 ] is found to be $$\\sigma _{D^{0}}^{y^\\star \\in [-2.29, 0]} = 48.2 \\pm 0.3 \\pm 4.5 \\,\\upmu \\text {b}/\\text {nucleon}$$ σ D 0 y ⋆ ∈ [ - 2.29 , 0 ] = 48.2 ± 0.3 ± 4.5 μ b / nucleon where the first uncertainty is statistical and the second is systematic. The $${{{D}} ^0}-{{\\hspace{0.0pt}\\overline{\\hspace{0.0pt}{D}}} {}^0} $$ D 0 - D ¯ 0 production asymmetry is also evaluated and suggests a trend towards negative values at large negative $$y^{\\star }$$ y ⋆ . The considered models do not account precisely for all the features observed in the LHCb data, but theoretical predictions including 1 $$\\%$$ % intrinsic charm and 10 $$\\%$$ % recombination contributions better describe the data than the other models considered.
Publisher: Springer Science and Business Media LLC
Date: 27-07-2015
DOI: 10.1038/NPHYS3415
No related grants have been discovered for Olivier Leroy.