P. Billoir
A5016536576- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Neutrino Physics Research
- Particle Detector Development and Performance
- Computational Physics and Python Applications
- Dark Matter and Cosmic Phenomena
- Black Holes and Theoretical Physics
- Particle Accelerators and Free-Electron Lasers
- Astrophysics and Cosmic Phenomena
- Atomic and Subatomic Physics Research
- Medical Imaging Techniques and Applications
- Superconducting Materials and Applications
- Nuclear physics research studies
- Radiation Detection and Scintillator Technologies
- Stochastic processes and statistical mechanics
- Distributed and Parallel Computing Systems
- International Science and Diplomacy
- Nuclear Physics and Applications
- Radiation Therapy and Dosimetry
- Cold Atom Physics and Bose-Einstein Condensates
- Advanced NMR Techniques and Applications
- Geophysics and Gravity Measurements
- Pulsars and Gravitational Waves Research
- Radioactive Decay and Measurement Techniques
Laboratoire de Physique Nucléaire et de Hautes Énergies
2016-2025
Sorbonne Université
2008-2025
Délégation Paris 7
2008-2025
Centre National de la Recherche Scientifique
2014-2025
Sorbonne Paris Cité
2019-2025
Université Paris Cité
2008-2025
Universitat Ramon Llull
2023
Imperial College London
2022
University of Chinese Academy of Sciences
2020
Peking University
2020
Observations of exotic structures in the J/ψp channel, which we refer to as charmonium-pentaquark states, Λ0b→J/ψK−p decays are presented. The data sample corresponds an integrated luminosity 3 fb−1 acquired with LHCb detector from 7 and 8 TeV pp collisions. An amplitude analysis three-body final state reproduces two-body mass angular distributions. To obtain a satisfactory fit seen spectrum, it is necessary include two Breit-Wigner amplitudes that each describe resonant state. significance...
Using proton-proton collision data at centre-of-mass energies of $\sqrt{s} = 7$, $8$ and $13\mathrm{\,TeV}$ recorded by the LHCb experiment Large Hadron Collider, corresponding to an integrated luminosity $9\mathrm{\,fb}^{-1}$, invariant mass spectrum $J/ψ$ pairs is studied. A narrow structure around $6.9\mathrm{\,GeV/}c^2$ matching lineshape a resonance broad just above twice are observed. The deviation from nonresonant $J/ψ$-pair production five standard deviations in region between $6.2$...
First evidence of a structure in the J/ψΛ invariant mass distribution is obtained from an amplitude analysis Ξb-→J/ψΛK- decays. The observed consistent with being due to charmonium pentaquark strangeness significance 3.1σ including systematic uncertainties and look-elsewhere effect. Its width are determined be 4458.8±2.9-1.1+4.7MeV 17.3±6.5-5.7+8.0MeV, respectively, where quoted statistical systematic. also two resonances. In addition, narrow excited Ξ- states, Ξ1690- Ξ1820-, seen for first...
The first simultaneous test of muon-electron universality using B^{+}→K^{+}ℓ^{+}ℓ^{-} and B^{0}→K^{*0}ℓ^{+}ℓ^{-} decays is performed, in two ranges the dilepton invariant-mass squared, q^{2}. analysis uses beauty mesons produced proton-proton collisions collected with LHCb detector between 2011 2018, corresponding to an integrated luminosity 9 fb^{-1}. Each four lepton measurements reported either given q^{2} interval or supersedes previous measurements. results are compatible predictions...
An amplitude analysis of B^{-}→J/ψΛp[over ¯] decays is performed using 4400 signal candidates selected on a data sample pp collisions recorded at center-of-mass energies 7, 8, and 13 TeV with the LHCb detector, corresponding to an integrated luminosity 9 fb^{-1}. A narrow resonance in J/ψΛ system, consistent pentaquark candidate strangeness, observed high significance. The mass width this new state are measured be 4338.2±0.7±0.4 MeV 7.0±1.2±1.3 MeV, where first uncertainty statistical second...
A simultaneous analysis of the B+→K+ℓ+ℓ− and B0→K*0ℓ+ℓ− decays is performed to test muon-electron universality in two ranges square dilepton invariant mass, q2. The measurement uses a sample beauty meson produced proton-proton collisions collected with LHCb detector between 2011 2018, corresponding an integrated luminosity 9 fb−1. sequence multivariate selections strict particle identification requirements produce higher signal purity better statistical sensitivity per unit than previous...
A combined amplitude analysis is performed for the decays B^{0}→D[over ¯]^{0}D_{s}^{+}π^{-} and B^{+}→D^{-}D_{s}^{+}π^{+}, which are related by isospin symmetry. The based on data collected LHCb detector in proton-proton collisions at center-of-mass energies of 7, 8, 13 TeV. full sample corresponds to an integrated luminosity 9 fb^{-1}. Two new resonant states with masses 2.908±0.011±0.020 GeV widths 0.136±0.023±0.013 observed, decay D_{s}^{+}π^{+} D_{s}^{+}π^{-} respectively. former state...
The branching fraction $\mathcal{B}({B}^{0}\ensuremath{\rightarrow}{D}^{*\ensuremath{-}}{\ensuremath{\tau}}^{+}{\ensuremath{\nu}}_{\ensuremath{\tau}})$ is measured relative to that of the normalization mode ${B}^{0}\ensuremath{\rightarrow}{D}^{*\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$ using hadronic...
The ratios of branching fractions $\mathcal{R}({D}^{*})\ensuremath{\equiv}\mathcal{B}(\overline{B}\ensuremath{\rightarrow}{D}^{*}{\ensuremath{\tau}}^{\ensuremath{-}}{\overline{\ensuremath{\nu}}}_{\ensuremath{\tau}})/\mathcal{B}(\overline{B}\ensuremath{\rightarrow}{D}^{*}{\ensuremath{\mu}}^{\ensuremath{-}}{\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}})$ and...
The ratio of the B0s and B0 fragmentation fractions, fs/fd, in proton-proton collisions at LHC, is obtained as a function B-meson transverse momentum collision center-of-mass energy from combined analysis different B-decay channels measured by LHCb experiment. results are described linear meson or with inspired Tsallis statistics. Precise measurements branching fractions B0s→J/ψϕ B0s→D−sπ+ decays performed, reducing their uncertainty about factor 2 respect to previous world averages....
Resonant contributions in $B^0 \rightarrow \overline{D}^0 D^+_s\pi^-$ and $B^+\rightarrow D^- D^+_s\pi^+$ decays are determined with an amplitude analysis, which is performed both separately simultaneously, where the latter case isospin symmetry between assumed. The analysis based on data collected by LHCb detector proton-proton collisions at center-of-mass energies of 7, 8 13 $\rm{TeV}$. full sample corresponds to integrated luminosity 9 $\rm fb^{-1}$. A doubly charged spin-0 open-charm...
A bstract The cross-sections of exclusive (coherent) photoproduction J/ψ and ψ (2S) mesons in ultra-peripheral PbPb collisions at a nucleon-nucleon centre-of-mass energy 5 . 02 TeV are measured using data sample corresponding to an integrated luminosity 228 ± 10 μb − 1 , collected by the LHCb experiment 2018. differential separately as function transverse momentum rapidity nucleus-nucleus frame for mesons. be $$ {\sigma}_{J/\psi}^{\textrm{coh}} <mml:math...
A measurement of time-dependent <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi>C</a:mi><a:mi>P</a:mi></a:math> violation in the decays <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:msup><c:mi>B</c:mi><c:mn>0</c:mn></c:msup></c:math> and <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:msup><e:mover accent="true"><e:mi>B</e:mi><e:mo stretchy="false">¯</e:mo></e:mover><e:mn>0</e:mn></e:msup></e:math> mesons to...
The production rate of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:msubsup><a:mi mathvariant="normal">Λ</a:mi><a:mi>b</a:mi><a:mn>0</a:mn></a:msubsup></a:math> baryons relative to <d:math xmlns:d="http://www.w3.org/1998/Math/MathML" display="inline"><d:msup><d:mi>B</d:mi><d:mn>0</d:mn></d:msup></d:math> mesons in <f:math xmlns:f="http://www.w3.org/1998/Math/MathML" display="inline"><f:mi>p</f:mi><f:mi>p</f:mi></f:math> collisions at a center-of-mass energy...
A measurement of the time-dependent ratio <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:msup><a:mi>D</a:mi><a:mn>0</a:mn></a:msup><a:mo stretchy="false">→</a:mo><a:mrow><a:msup><a:mi>K</a:mi><a:mo>+</a:mo></a:msup><a:msup><a:mi>π</a:mi><a:mo>−</a:mo></a:msup></a:mrow></a:math> to <d:math xmlns:d="http://www.w3.org/1998/Math/MathML" display="inline"><d:mrow><d:mrow><d:msup><d:mrow><d:mover accent="true"><d:mrow><d:mi>D</d:mi></d:mrow><d:mrow><d:mo...
Abstract Charged-particle trajectories are usually reconstructed with the LHCb detector using combined information from tracking devices placed upstream and downstream of 4 T m dipole magnet. Trajectories only tracker magnet, which referred to as tracks, have not been used for physics analysis date. The challenges reconstruction long-lived particles tracks use discussed solutions proposed. feasibility performance studied samples $$\varvec{\Lambda }$$ <mml:math...
The first study of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi>J</a:mi><a:mo>/</a:mo><a:mi>ψ</a:mi><a:mi>ϕ</a:mi></a:math> production in diffractive processes proton-proton collisions is presented. based on an LHCb dataset recorded at center-of-mass energy 13 TeV, corresponding to integrated luminosity <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mn>5</c:mn><c:mtext> </c:mtext><c:mtext>...
Events containing a Z boson and charm jet are studied for the first time in forward region of proton-proton collisions. The data sample used corresponds to an integrated luminosity 6 fb^{-1} collected at center-of-mass energy 13 TeV with LHCb detector. In events jet, fraction jets is determined intervals Z-boson rapidity range 2.0<y(Z)<4.5. A sizable enhancement observed forwardmost y(Z) interval, which could be indicative valencelike intrinsic-charm component proton wave function.
An amplitude analysis of the B+→D+sD−sK+ decay is carried out to study for first time its intermediate resonant contributions, using proton-proton collision data collected with LHCb detector at center-of-mass energies 7, 8, and 13 TeV. A near-threshold peaking structure, referred as X(3960), observed in D+sD−s invariant-mass spectrum significance greater than 12 standard deviations. The mass, width, quantum numbers structure are measured be 3956±5±10 MeV, 43±13±8 JPC=0++, respectively, where...
The time-integrated CP asymmetry in the Cabibbo-suppressed decay D^{0}→K^{-}K^{+} is measured using proton-proton collision data, corresponding to an integrated luminosity of 5.7 fb^{-1} collected at a center-of-mass energy 13 TeV with LHCb detector. D^{0} mesons are required originate from promptly produced D^{*+}→D^{0}π^{+} decays, and charge companion pion used determine flavor charm meson production. be A_{CP}(K^{-}K^{+})=[6.8±5.4±1.6]×10^{-4} where first uncertainty statistical second...
Two new excited states, Ω_{c}(3185)^{0} and Ω_{c}(3327)^{0}, are observed in the Ξ_{c}^{+}K^{-} invariant-mass spectrum using proton-proton collision data collected by LHCb experiment, corresponding to an integrated luminosity of 9 fb^{-1}. Five previously Ω_{c}^{0} states confirmed, namely Ω_{c}(3000)^{0}, Ω_{c}(3050)^{0}, Ω_{c}(3065)^{0}, Ω_{c}(3090)^{0}, Ω_{c}(3119)^{0}. The masses widths these seven measured with highest precision date.