J. Closier
A5107925387- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Neutrino Physics Research
- Particle Detector Development and Performance
- Dark Matter and Cosmic Phenomena
- Black Holes and Theoretical Physics
- Computational Physics and Python Applications
- Particle Accelerators and Free-Electron Lasers
- Superconducting Materials and Applications
- Medical Imaging Techniques and Applications
- Distributed and Parallel Computing Systems
- Atomic and Subatomic Physics Research
- Scientific Computing and Data Management
- Advanced Data Storage Technologies
- Nuclear physics research studies
- Stochastic processes and statistical mechanics
- Radiation Detection and Scintillator Technologies
- International Science and Diplomacy
- Cosmology and Gravitation Theories
- Advanced NMR Techniques and Applications
- Markov Chains and Monte Carlo Methods
- Astrophysics and Cosmic Phenomena
- Stochastic processes and financial applications
- Geophysics and Gravity Measurements
European Organization for Nuclear Research
2016-2025
Instituto de Física Corpuscular
2023-2024
Universitat de València
2023-2024
École Polytechnique Fédérale de Lausanne
2023
Kharkiv Institute of Physics and Technology
2023
Institute for Nuclear Research
2023
University of Zurich
2011-2023
University of Chinese Academy of Sciences
2023
University of Maryland, College Park
2017
Centro Brasileiro de Pesquisas Físicas
2013-2016
This paper presents the design of LHCb trigger and its performance on data taken at LHC in 2011. A principal goal is to perform flavour physics measurements, designed distinguish charm beauty decays from light quark background. Using a combination lepton identification measurements particles' transverse momenta selects particles originating hadrons, which typically fly finite distance before decaying. The reduces roughly 11 MHz bunch-bunch crossings that contain least one inelastic pp...
The production of J/psi mesons in proton-proton collisions at sqrt(s)=7 TeV is studied with the LHCb detector LHC. differential cross-section for prompt measured as a function transverse momentum pT and rapidity y fiducial region 0<pT<14 GeV/c 2.0<y<4.5. fraction from b-hadron decays are also same ranges. analysis based on data sample corresponding to an integrated luminosity 5.2pb-1. cross-sections over 10.52 +/- 0.04 1.40 +1.64/-2.20 mub 1.14 0.01 0.16 decays, where first uncertainty...
The DIRAC system was developed in order to provide a complete solution for using the distributed computing resources of LHCb experiment at CERN data production and analysis. It allows concurrent use over 10K CPUs 10M file replicas many tens sites. sites can be part Computing Grid such as WLCG or standalone clusters all integrated single management structure. is generic with specific functionality incorporated through number plug-in modules. easily adapted needs other communities. Special...
Using data collected with the LHCb detector in proton-proton collisions at a centre-of-mass energy of 7 TeV, hadronic decay Bs -> J/psi f0(980) is observed. This CP eigenstate mode could be used to measure mixing-induced violation B_s system. fit pi+ pi- mass spectrum interfering resonances gives R_{f0/phi} = [Gamma(Bs f0, f0 pi-)]/[Gamma(Bs phi, phi K+K-)] 0.252^{+0.046+0.027}_{-0.032-0.033}, where uncertainties are statistical and systematic, respectively.
DIRAC, the LHCb community Grid solution, was considerably reengineered in order to meet all requirements for processing data coming from experiment. It is covering tasks starting with raw transportation experiment area grid storage, up final user analysis. The DIRAC3 version of system includes a fully security compliant framework building service oriented distributed systems; complete Pilot Job creating efficient workload management several subsystems manage high level operations like...
The relative abundance of the three decay modes ${B}^{0}\ensuremath{\rightarrow}{D}^{\ensuremath{-}}{K}^{+}$, ${B}^{0}\ensuremath{\rightarrow}{D}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$, and ${B}_{s}^{0}\ensuremath{\rightarrow}{D}_{s}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$ produced in 7 TeV $pp$ collisions at LHC is determined from data corresponding to an integrated luminosity $35\text{ }\text{ }{\mathrm{pb}}^{\ensuremath{-}1}$. branching fraction...
Six of the key physics measurements that will be made by LHCb experiment, concerning CP asymmetries and rare B decays, are discussed in detail. The "road map" towards precision is presented, including use control channels other techniques to understand performance detector with first data from LHC.
The cross-section for inclusive phi meson production in pp collisions at a centre-of-mass energy of sqrt(s) = 7 TeV has been measured with the LHCb detector Large Hadron Collider. differential is as function transverse momentum p_T and rapidity y region 0.6 < 5.0 GeV/c 2.44 4.06. this kinematic range sigma(pp -> X) 1758 pm 19(stat) ^{+43}_{-14}(syst) 182(scale) microbarn, where first systematic uncertainty depends on second related to overall scale. Predictions based Pythia 6.4 generator...
The $\bar{\Lambda} / \Lambda$ and K^0_\mathrm{S}$ production ratios are measured by the LHCb detector from $0.3\,\mathrm{nb}^{-1}$ of $pp$ collisions delivered LHC at $\sqrt{s} = 0.9$\,TeV $1.8\,\mathrm{nb}^{-1}$ 7$\,TeV. Both presented as a function transverse momentum, $p_\mathrm{T}$, rapidity, $y$, in ranges {$0.15 < p_\mathrm{T} 2.50\,\mathrm{GeV}/c$} {$2.0<y<4.5$}. Results two energies good agreement rapidity loss, $\Delta y y_\mathrm{beam} - y$, consistent with previous measurements....
We present LHCbDirac, an extension of the DIRAC community Grid solution that handles LHCb specificities. The software has been developed for many years within only. Nowadays it is a generic software, used by scientific communities worldwide. Each wanting to take advantage develop extension, containing all necessary code handling their specific cases. LHCbDirac actively implementing computing model and workflows distributed activities LHCb. Such include real data processing (reconstruction,...
The Worldwide LHC Computing Grid relies on the network as a critical part of its infrastructure and therefore needs to guarantee effective usage prompt detection resolution any issues, including connection failures, congestion, traffic routing, etc. WLCG Network Transfer Metrics project aims integrate combine all network-related monitoring data collected by infrastructure. This includes FTS information, from XRootD federation, well results perfSONAR tests. main challenge consists further...
This paper describes DIRAC, the LHCb Monte Carlo production system. DIRAC has a client/server architecture based on: Compute elements distributed among collaborating institutes; Databases for management, bookkeeping (the metadata catalogue) and software configuration; Monitoring cataloguing services updating accessing databases. Locally installed agents implemented in Python monitor local batch queue, interrogate database any outstanding requests using XML-RPC protocol initiate job...
This contribution describes how Cloud resources have been integrated in the LHCb Distributed Computing. is using its specific Dirac extension (LHCbDirac) as an interware for So far, it was seamlessly integrating Grid and Computer clusters. The cloud of DIRAC (VMDIRAC) allows integration computing infrastructures. It able to interact with multiple types infrastructures commercial institutional clouds, supported by interfaces (Amazon EC2, OpenNebula, OpenStack CloudStack) – instantiates,...
The worldwide computing grid is essential to the LHC experiments in analysing data collected by detectors. Within LHCb, model aims simulate at Tier-2 sites as well non-grid resources. reconstruction, stripping and analysis of produced LHCb will pimarily place Tier-1 centres. challenge DC06 started May 2006 with primary being exercise mod produce events which be used for analyses forthcoming physics book. This paper gives an overview addresses challenges experiences during DC06. management...
In the LHCb experiment a wide variety of Monte Carlo simulated samples needs to be produced for experiment's physics program. productions are handled centrally similarly all massive processing data in experiment. order cope with large set different types simulation samples, necessary procedures based on common infrastructures have been up numerical event type identification code used throughout. The various elements procedure, from writing configuration an deploying them production...