0000000000132495

AUTHOR

Francesco Bossu

showing 34 related works from this author

Measurement of charged jet production cross sections and nuclear modification in p–Pb collisions at sNN=5.02 TeV

2015

Charged jet production cross sections in p–Pb collisions at √sNN = 5.02 TeV measured with the ALICE detector at the LHC are presented. Using the anti-kT algorithm, jets have been reconstructed in the central rapidity region from charged particles with resolution parameters R = 0.2 and R = 0.4. The reconstructed jets have been corrected for detector effects and the underlying event background. To calculate the nuclear modification factor, RpPb, of charged jets in p–Pb collisions, a pp reference was constructed by scaling previously measured charged jet spectra at √s = 7 TeV. In the transverse momentum range 20 ≤ pT, ch jet ≤ 120 GeV/c, RpPb is found to be consistent with unity, indicating th…

PhysicsNuclear and High Energy PhysicsJet (fluid)Particle physicsRange (particle radiation)Large Hadron ColliderAstrophysics::High Energy Astrophysical PhenomenaNuclear matterSpectral lineCharged particleNuclear physicsHigh Energy Physics::ExperimentRapidityNuclear ExperimentScalingPhysics Letters B
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Measurement of PromptD-Meson Production inp−PbCollisions atsNN=5.02  TeV

2014

The p_{T}-differential production cross sections of the prompt charmed mesons D^{0}, D^{+}, D^{*+}, and D_{s}^{+} and their charge conjugate in the rapidity interval -0.96<y_{cms}<0.04 were measured in p-Pb collisions at a center-of-mass energy sqrt[s_{NN}]=5.02 TeV with the ALICE detector at the LHC. The nuclear modification factor R_{pPb}, quantifying the D-meson yield in p-Pb collisions relative to the yield in pp collisions scaled by the number of binary nucleon-nucleon collisions, is compatible within the 15%-20% uncertainties with unity in the transverse momentum interval 1<p_{T}<24 GeV/c. No significant difference among the R_{pPb} of the four D-meson species is observed. The results…

PhysicsParticle physicsMeson010308 nuclear & particles physicsHadronGeneral Physics and Astronomy7. Clean energy01 natural sciencesNuclear physicsMomentum0103 physical sciencesD mesonHigh Energy Physics::ExperimentProduction (computer science)RapidityNuclear Experiment010306 general physicsEnergy (signal processing)BosonPhysical Review Letters
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J/ψ suppression at forward rapidity in Pb–Pb collisions at sNN=5.02 TeV

2017

The inclusive J/$\psi$ production has been studied in Pn-Pb and pp collisions at the centre-of-mass energy per nucleon pair $\sqrt{s_{\rm NN}}=5.02$ TeV, using the ALICE detector at the CERN LHC. The J/$\psi$ meson is reconstructed, in the centre-of-mass rapidity interval $2.5<y<4$ and in the transverse-momentum range $p_{\rm T}<12$ GeV/$c$, via its decay to a muon pair. In this Letter, we present results on the inclusive J/$\psi$ cross section in pp collisions at $\sqrt{s}=5.02$ TeV and on the nuclear modification factor $R_{\rm AA}$. The latter is presented as a function of the centrality of the collision and, for central collisions, as a function of the transverse momentum $p_{\rm T}$ of…

PhysicsNuclear and High Energy PhysicsParticle physicsMuonMeson010308 nuclear & particles physics01 natural sciencesNuclear physics0103 physical sciencesQuark–gluon plasmaHigh Energy Physics::ExperimentRapidityProduction (computer science)Impact parameterNuclear Experiment010306 general physicsNucleonEnergy (signal processing)Physics Letters B
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Production of Muons from Heavy Flavor Decays at Forward Rapidity inppand Pb-Pb Collisions atsNN=2.76  TeV

2012

The ALICE Collaboration has measured the inclusive production of muons from heavy-flavor decays at forward rapidity, 2.5 < y < 4, in pp and Pb-Pb collisions at root s(NN) = 2.76 TeV. The p(t)-differential inclusive cross section of muons from heavy-flavor decays in pp collisions is compared to perturbative QCD calculations. The nuclear modification factor is studied as a function of p(t) and collision centrality. A weak suppression is measured in peripheral collisions. In the most central collisions, a suppression of a factor of about 3-4 is observed in 6 < p(t) < 10 GeV/c. The suppression shows no significant p(t) dependence.

PhysicsParticle physicsMuon010308 nuclear & particles physicsHigh Energy Physics::PhenomenologyGeneral Physics and AstronomyPerturbative QCDModification factor01 natural sciencesNuclear physics0103 physical sciencesHigh Energy Physics::ExperimentRapidityNuclear Experiment010306 general physicsFlavorPhysical Review Letters
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Elliptic flow of muons from heavy-flavour hadron decays at forward rapidity in Pb–Pb collisions at sNN=2.76 TeV

2016

The elliptic flow, $v_{2}$, of muons from heavy-flavour hadron decays at forward rapidity ($2.5 < y < 4$) is measured in Pb--Pb collisions at $\sqrt{s_{\rm NN}}$~=~2.76 TeV with the ALICE detector at the LHC. The scalar product, two- and four-particle $Q$ cumulants and Lee-Yang zeros methods are used. The dependence of the $v_2$ of muons from heavy-flavour hadron decays on the collision centrality, in the range 0--40\%, and on transverse momentum, $p_{\rm T}$, is studied in the interval $3 < p_{\rm T} < 10$~GeV/$c$. A positive $v_2$ is observed with the scalar product and two-particle $Q$ cumulants in semi-central collisions (10--20\% and 20--40\% centrality classes) for the $p_{\rm T}$ int…

PhysicsQuarkNuclear and High Energy PhysicsParticle physicsMuon010308 nuclear & particles physicsHigh Energy Physics::PhenomenologyElliptic flowHadron01 natural sciencesHadronizationNuclear physicsPion0103 physical sciencesHigh Energy Physics::ExperimentRapidityImpact parameterNuclear Experiment010306 general physicsPhysics Letters B
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Azimuthal anisotropy ofD-meson production in Pb-Pb collisions atsNN=2.76TeV

2014

The production of the prompt charmed mesons D0, D+, and D*+ relative to the reaction plane was measured in Pb-Pb collisions at a center-of-mass energy per nucleon-nucleon collision of √sNN=2.76TeV with the ALICE detector at the CERN Large Hadron Collider. D mesons were reconstructed via their hadronic decays at central rapidity in the transverse-momentum (p_T) interval 2–16 GeV/c. The azimuthal anisotropy is quantified in terms of the second coefficient v2 in a Fourier expansion of the D-meson azimuthal distribution and in terms of the nuclear modification factor R_AA, measured in the direction of the reaction plane and orthogonal to it. The v2 coefficient was measured with three different …

PhysicsNuclear and High Energy PhysicsParticle physicsLarge Hadron ColliderMeson010308 nuclear & particles physicsPlane (geometry)Hadron01 natural sciences7. Clean energyNuclear physicsYield (chemistry)0103 physical sciencesD mesonHigh Energy Physics::ExperimentRapidityNuclear Experiment010306 general physicsAnisotropyPhysical Review C
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Evidence for Exotic Hadron Contributions toΛb0→J/ψpπ−Decays

2016

A full amplitude analysis of $\Lambda_b^0 \to J/\psi p \pi^-$ decays is performed with a data sample acquired with the LHCb detector from 7 and 8 TeV $pp$ collisions, corresponding to an integrated luminosity of 3 fb$^{-1}$. A significantly better description of the data is achieved when, in addition to the previously observed nucleon excitations $N\to p\pi^-$, either the $P_c(4380)^+$ and $P_c(4450)^+\to J/\psi p$ states, previously observed in $\Lambda_b^0 \to J/\psi p K^-$ decays, or the $Z_c(4200)^-\to J/\psi \pi^-$ state, previously reported in $B^0 \to J/\psi K^+ \pi^-$ decays, or all three, are included in the amplitude models. The data support a model containing all three exotic sta…

PhysicsParticle physics010308 nuclear & particles physicsPartial wave analysisQuark modelGeneral Physics and AstronomyExotic hadronLambda01 natural sciencesLuminosityNuclear physicsAmplitude0103 physical sciencesHigh Energy Physics::ExperimentProduction (computer science)010306 general physicsNucleonPhysical Review Letters
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ϕ-Meson production at forward rapidity in p–Pb collisions at sNN=5.02 TeV and in pp collisions at s=2.76 TeV

2017

The first study of $\phi$-meson production in p–Pb collisions at forward and backward rapidity, at a nucleon– nucleon centre-of-mass energy $\sqrt{S_{NN}}$= 5.02 TeV, has been performed with the ALICE apparatus at the LHC. The $\phi$-mesons have been identified in the dimuon decay channel in the transverse momentum ($p_T$) range 1 < $p_T$ < 7 GeV/c, both in the p-going (2.03 < y < 3.53) and the Pb-going (−4.46 < y < −2.96) directions — where $y$ stands for the rapidity in the nucleon–nucleon centre-of-mass — the integrated luminosity amounting to 5.01 ± 0.19 nb$^{−1}$ and 5.81 ± 0.20 nb$^{−1}$ , respectively, for the two data samples. Differential cross sections as a function of transverse …

PhysicsNuclear and High Energy PhysicsParticle physicsMeson010308 nuclear & particles physicsBranching fractionHadronStrangeness01 natural sciencesNuclear physics0103 physical sciencesHigh Energy Physics::ExperimentProduction (computer science)RapidityAbsorption (logic)Nuclear Experiment010306 general physicsNucleonPhysics Letters B
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Anisotropic Flow of Charged Particles in Pb-Pb Collisions atsNN=5.02  TeV

2016

We report the first results of elliptic (v2), triangular (v3), and quadrangular (v4) flow of charged particles in Pb-Pb collisions at a center-of-mass energy per nucleon pair of √sNN=5.02  TeV with the ALICE detector at the CERN Large Hadron Collider. The measurements are performed in the central pseudorapidity region |η|<0.8 and for the transverse momentum range 0.2<pT<5  GeV/c. The anisotropic flow is measured using two-particle correlations with a pseudorapidity gap greater than one unit and with the multiparticle cumulant method. Compared to results from Pb-Pb collisions at √sNN=2.76  TeV, the anisotropic flow coefficients v2, v3, and v4 are found to increase by (3.0±0.6)%, (4.3±1.4)%, …

PhysicsRange (particle radiation)Large Hadron Collider010308 nuclear & particles physicsElliptic flowGeneral Physics and Astronomy01 natural sciences7. Clean energyCharged particleNuclear physicsPseudorapidity0103 physical sciencesQuark–gluon plasmaHigh Energy Physics::ExperimentNuclear Experiment010306 general physicsNucleonAnisotropyPhysical Review Letters
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Pseudorapidity and transverse-momentum distributions of charged particles in proton–proton collisions at s=13 TeV

2016

The pseudorapidity (η) and transverse-momentum (pT) distributions of charged particles produced in proton-proton collisions are measured at the centre-of-mass energy s√ = 13 TeV. The pseudorapidity distribution in |η|< 1.8 is reported for inelastic events and for events with at least one charged particle in | η|< 1. The pseudorapidity density of charged particles produced in the pseudorapidity region |η|< 0.5 is 5.31 ± 0.18 and 6.46 ± 0.19 for the two event classes, respectively. The transverse-momentum distribution of charged particles is measured in the range 0.15 < pT < 20 GeV/c and |η|< 0.8 for events with at least one charged particle in |η|< 1. The correlation between transverse momen…

PhysicsNuclear and High Energy PhysicsParticle physicsTime projection chamber010308 nuclear & particles physicsHadronPartonStrangeness01 natural sciences7. Clean energyCharged particleHadronizationNuclear physicsPseudorapidity0103 physical sciencesHigh Energy Physics::ExperimentMultiplicity (chemistry)Nuclear Experiment010306 general physicsPhysics Letters B
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Measurement of electrons from semileptonic heavy-flavor hadron decays inppcollisions ats=2.76  TeV

2015

The pT-differential production cross section of electrons from semileptonic decays of heavy-flavor hadrons has been measured at midrapidity in proton-proton collisions at s=2.76TeV in the transverse momentum range 0.5<pT<12GeV/c with the ALICE detector at the LHC. The analysis was performed using minimum bias events and events triggered by the electromagnetic calorimeter. Predictions from perturbative QCD calculations agree with the data within the theoretical and experimental uncertainties.

Quantum chromodynamicsPhysicsSemileptonic decayNuclear and High Energy PhysicsParticle physicsLarge Hadron ColliderPhysics::Instrumentation and Detectors010308 nuclear & particles physicsHigh Energy Physics::PhenomenologyHadronPerturbative QCD7. Clean energy01 natural sciencesNuclear physicsParticle decay0103 physical sciencesQuark–gluon plasmaHigh Energy Physics::ExperimentNuclear Experiment010306 general physicsQCD matterPhysical Review D
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Production of charged pions, kaons and protons at large transverse momenta in pp and Pb–Pb collisions at sNN=2.76 TeV

2014

Transverse momentum spectra of pi(+/-), K-+/- and p((p) over bar) up to p(T) = 20 GeV/c at mid-rapidity in pp, peripheral (60-80%) and central (0-5%) Pb-Pb collisions at v root s(NN) = 2.76 TeV have been measured using the ALICE detector at the Large Hadron Collider. The proton-to-pion and the kaon-to-pionratios both show a distinct peak at p(T) approximate to 3 GeV/c in central Pb-Pb collisions. Below the peak, p(T) 10 GeV/c particle ratios in pp and Pb-Pb collisions are in agreement and the nuclear modification factors for pi(+/-), K-+/- and p((p) over bar) indicate that, within the systematic and statistical uncertainties, the suppression is the same. This suggests that the chemical comp…

PhysicsNuclear and High Energy PhysicsParticle physicsLarge Hadron ColliderJet (particle physics)Charged particleSpectral lineBaryonNuclear physicsTransverse planePionHigh Energy Physics::ExperimentNuclear ExperimentBar (unit)Physics Letters B
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Multi-particle azimuthal correlations in p-Pb and Pb-Pb collisions at the CERN Large Hadron Collider

2014

Measurements of multi-particle azimuthal correlations (cumulants) for charged particles in p-Pb and Pb-Pb collisions are presented. They help address the question of whether there is evidence for global, flow-like, azimuthal correlations in the p-Pb system. Comparisons are made to measurements from the larger Pb-Pb system, where such evidence is established. In particular, the second harmonic two-particle cumulants are found to decrease with multiplicity, characteristic of a dominance of few-particle correlations in p-Pb collisions. However, when a $|\Delta \eta|$ gap is placed to suppress such correlations, the two-particle cumulants begin to rise at high-multiplicity, indicating the prese…

Pb-Pb collisionsazimuthal correlationsPb-Pb and p-Pb collisions at the LHCPpb CollisionsHigh multiplicityppQUARK-GLUON PLASMAALICEp-Pb collisionsRoot-S(Nn)=5.02 Tevcharged particlesPbPbNuclear Experiment (nucl-ex)Nuclear ExperimentPhysicsLarge Hadron Colliderazimuthal correlations; p-Pb collisions; Pb-Pb collisionsFlowPhysicsLong-RangeCharged particle3. Good health:Mathematics and natural scienses: 400::Physics: 430::Nuclear and elementary particle physics: 431 [VDP]AzimuthPRIRODNE ZNANOSTI. Fizika.LHCThird harmonicLHC; ALICE; pp; PbPb; Azimuthal correlationsParticle Physics - ExperimentParticle physicsNuclear and High Energy PhysicsVDP::Matematikk og naturvitenskap: 400::Fysikk: 430::Kjerne- og elementærpartikkelfysikk: 431FOS: Physical sciencesEccentricities[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]Nuclear physicsNuclear Physics - ExperimentDependenceCumulantNUCLEUS-NUCLEUS COLLISIONS; QUARK-GLUON PLASMA; ANGULAR-CORRELATIONSTransverse-Momentumta114VDP::Mathematics and natural scienses: 400::Physics: 430::Nuclear and elementary particle physics: 431NUCLEUS-NUCLEUS COLLISIONS:Matematikk og naturvitenskap: 400::Fysikk: 430::Kjerne- og elementærpartikkelfysikk: 431 [VDP]ALICE experimentMultiplicity (mathematics)ANGULAR-CORRELATIONSNATURAL SCIENCES. Physics.Quark–gluon plasma
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Search for weakly decaying b -flavored pentaquarks

2018

Investigations of the existence of pentaquark states containing a single $b$ (anti)quark decaying weakly into four specific final states J/$\psi K^+\pi^- p$, J/$\psi K^- \pi^- p$, J/$\psi K^- \pi^+ p$, and $J/\psi \phi (1020) p$ are reported. The data sample corresponds to an integrated luminosity of 3.0/fb in 7 and 8 TeV pp collisions acquired with the LHCb detector. Signals are not observed and upper limits are set on the product of the production cross section times branching fraction with respect to that of the $\Lambda_b$.

baryon: exoticPhysics and Astronomy (miscellaneous)7000 GeV-cms8000 GeV-cms01 natural sciencesPhysics Particles & FieldsSettore FIS/04 - Fisica Nucleare e SubnucleareHigh Energy Physics - ExperimentLuminosityHigh Energy Physics - Experiment (hep-ex)Hadron-Hadron scattering (experiments)scattering [p p][PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex]exotic [baryon]LHCb - Abteilung HintonpentaquarkPhysics8000 GeV-cmsPhysicsParticle physicsPentaquark3. Good healthchannel cross section: branching ratio: upper limitExotic baryonpentaquark --> J/psi(3100) K- pi+ pBranching fraction Hadron-Hadron scattering (experiments) QCDpentaquark --> J/psi(3100) K- pi- pCERN LHC Coll7000 GeV-cmsPhysical Sciencespentaquark --> J/psi(3100) Phi(1020) pBranching fractionLHCcolliding beams [p p]Particle Physics - ExperimentQuarkParticle physicsp p: scatteringFOS: Physical sciencesAstronomy & AstrophysicsHadronsNOmultiquark[ PHYS.HEXP ] Physics [physics]/High Energy Physics - Experiment [hep-ex]0103 physical sciencesddc:530010306 general physicsLarge Hadron Collider (France and Switzerland)Science & Technologybranching ratio: upper limit [channel cross section]hep-ex010308 nuclear & particles physicsBranching fractionpentaquark --> J/psi(3100) K+ pi- pParticles and FieldGran Col·lisionador d'HadronsBottom quarkQCDLHC-BHEPLHCbHigh Energy Physics::ExperimentFísica de partículesExperimentsp p: colliding beamsexperimental resultsPhysical Review D
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Forward-central two-particle correlations in p–Pb collisions at sNN=5.02 TeV

2016

Two-particle angular correlations between trigger particles in the forward pseudorapidity range (2.5 < |η| < 4.0) and associated particles in the cen

Physicscongenital hereditary and neonatal diseases and abnormalitiesNuclear and High Energy PhysicsParticle physicsTime projection chamber010308 nuclear & particles physicsAtlas detector01 natural sciencesCharged particleNuclear physicsMuon spectrometerPseudorapidity0103 physical sciencesTransverse momentumRapidityMultiplicity (chemistry)010306 general physicsPhysics Letters B
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Measurement of CP asymmetries in two-body B(s)0 -meson decays to charged pions and kaons

2018

The time-dependent CP asymmetries in B0→π+π− and B0s→K+K− decays are measured using a data sample of p p collisions corresponding to an integrated luminosity of 3.0  fb−1, collected with the LHCb detector at center-of-mass energies of 7 and 8 TeV. The same data sample is used to measure the time-integrated CP asymmetries in B0→K+π− and B0s→π+K− decays. The results are Cπ+π−=−0.34±0.06±0.01, Sπ+π−=−0.63±0.05±0.01, CK+K−=0.20±0.06±0.02, SK+K−=0.18±0.06±0.02, AΔΓK+K−=−0.79±0.07±0.10, AB0CP=−0.084±0.004±0.003, and AB0sCP=0.213±0.015±0.007, where the first uncertainties are statistical and the second systematic. Evidence for CP violation is found in the B0s→K+K− decay for the first time.

PhysicsParticle physicsLuminosity (scattering theory)PionMeson010308 nuclear & particles physicsOscillation0103 physical sciencesCP violation010306 general physics01 natural sciencesMeasure (mathematics)Physical Review D
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Jet-like correlations with neutral pion triggers in pp and central Pb–Pb collisions at 2.76 TeV

2016

Physics letters / B B763, 238 - 250 (2016). doi:10.1016/j.physletb.2016.10.048

heavy ion: scattering:Kjerne- og elementærpartikkelfysikk: 431 [VDP]ROOT-S(NN)=200 GEVQUARK-GLUON PLASMA; TRANSVERSE-MOMENTUM DEPENDENCE; LEAD-LEAD COLLISIONS; ROOT-S(NN)=2.76 TEV; ROOT-S-NN=2.76 TEV; ATLAS DETECTOR; SUPPRESSION; COLLABORATION; PERSPECTIVE; HADRONSHadronATLAS DETECTORCOLLABORATION01 natural sciencespi: triggerfragmentation functionParticle identificationHigh Energy Physics - ExperimentQUARK-GLUON PLASMAHADRON CORRELATIONSHigh Energy Physics - Experiment (hep-ex)ALICEp-Pb collisionsANISOTROPIC FLOWLEAD-LEADscattering [p p][PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex]Nuclear Experiment (nucl-ex)ROOT-S(NN)=2.76 TEVPERSPECTIVENuclear ExperimentMonte CarloNuclear ExperimentPhysicsTime projection chamberHADRONSPerturbative QCDneutral pion ; lead-lead ; correlationsuppressioncharged particlelcsh:QC1-999Charged particleTRANSVERSE-MOMENTUM DEPENDENCE CENTRAL AU+AU COLLISIONS LEAD-LEAD COLLISIONS PLUS AU COLLISIONS QUARK-GLUON PLASMA HADRON CORRELATIONS ROOT-S-NN=2.76 TEV ROOT-S(NN)=200 GEV CHARGED-PARTICLES ANISOTROPIC FLOW.:Mathematics and natural scienses: 400::Physics: 430::Nuclear and elementary particle physics: 431 [VDP]PRIRODNE ZNANOSTI. Fizika.:Nuclear and elementary particle physics: 431 [VDP]CHARGED-PARTICLESflowLEAD-LEAD COLLISIONSperturbation theory [quantum chromodynamics]correlation: two-particleCOLLISIONSParticle physicsp p: scatteringPLUS AU COLLISIONSNuclear and High Energy PhysicseducationVDP::Matematikk og naturvitenskap: 400::Fysikk: 430::Kjerne- og elementærpartikkelfysikk: 431FOS: Physical sciences[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]transverse momentumtriggerstrigger [pi]114 Physical sciencesQUARK-GLUON PLASMA; TRANSVERSE-MOMENTUM DEPENDENCE; LEAD-LEAD; COLLISIONS; ROOT-S(NN)=2.76 TEV; ROOT-S-NN=2.76 TEV; ATLAS DETECTOR; SUPPRESSION; COLLABORATION; PERSPECTIVE; HADRONS530ROOT-S-NN=2.76 TEVNuclear physicsPionTRANSVERSE-MOMENTUM DEPENDENCEscattering [heavy ion]0103 physical sciencesFragmentation functionddc:530Nuclear Physics - Experimentquantum chromodynamics: perturbation theory010306 general physicscapturetwo-particle correlationstwo-particle [correlation]enhancementSUPPRESSIONneutral pionVDP::Mathematics and natural scienses: 400::Physics: 430::Nuclear and elementary particle physics: 431ta114CENTRAL AU+AU COLLISIONS010308 nuclear & particles physicsbackground:Matematikk og naturvitenskap: 400::Fysikk: 430::Kjerne- og elementærpartikkelfysikk: 431 [VDP]NATURAL SCIENCES. Physics.lead-leadcorrelationQuark–gluon plasmaproton-proton collisionsHigh Energy Physics::Experimenthadronlcsh:Physics
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Multiplicity dependence of jet-like two-particle correlation structures in p–Pb collisions at sNN=5.02 TeV

2015

Two-particle angular correlations between unidentified charged trigger and associated particles are measured by the ALICE detector in p-Pb collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV. The transverse-momentum range 0.7<pT,assoc<pT,trig<5.0 GeV/c is examined, to include correlations induced by jets originating from low momentum-transfer scatterings (minijets). The correlations expressed as associated yield per trigger particle are obtained in the pseudorapidity range |η|<0.9. The near-side long-range pseudorapidity correlations observed in high-multiplicity p-Pb collisions are subtracted from both near-side short-range and away-side correlations in order to remove the no…

PhysicsNuclear and High Energy PhysicsParticle physicsLarge Hadron Collider010308 nuclear & particles physicsScatteringBinary number01 natural sciencesUncorrelatedNuclear physicsCorrelationPseudorapidity0103 physical sciencesHigh Energy Physics::ExperimentMultiplicity (chemistry)Nuclear Experiment010306 general physicsGlauberPhysics Letters B
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Multi-strange baryon production in p Pb collisions at sNN=5.02 TeV

2016

The multi-strange baryon yields in Pb--Pb collisions have been shown to exhibit an enhancement relative to pp reactions. In this work, $\Xi$ and $\Omega$ production rates have been measured with the ALICE experiment as a function of transverse momentum, ${p_{\rm T}}$, in p-Pb collisions at a centre-of-mass energy of ${\sqrt{s_{\rm NN}}}$ = 5.02 TeV. The results cover the kinematic ranges 0.6 GeV/$c<{p_{\rm T}} <$7.2 GeV/$c$ and 0.8 GeV/$c<{p_{\rm T}}<$ 5 GeV/$c$, for $\Xi$ and $\Omega$ respectively, in the common rapidity interval -0.5 $<{y_{\rm CMS}}<$ 0. Multi-strange baryons have been identified by reconstructing their weak decays into charged particles. The ${p_{\rm T}}$ spectra are ana…

PhysicsNuclear and High Energy PhysicsParticle physics010308 nuclear & particles physicsHadronHyperonStrangeness7. Clean energy01 natural sciencesCharged particleNuclear physicsBaryonPion0103 physical sciencesQuark–gluon plasmaRapidityNuclear Experiment010306 general physicsPhysics Letters B
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Centrality Dependence of the Charged-Particle Multiplicity Density at Midrapidity in Pb-Pb Collisions atsNN=5.02  TeV

2016

The pseudorapidity density of charged particles, dNch/dη, at midrapidity in Pb-Pb collisions has been measured at a center-of-mass energy per nucleon pair of √sNN=5.02 TeV. For the 5% most central collisions, we measure a value of 1943 ± 54. The rise in dNch/dη as a function of √sNN p is steeper than that observed in proton-proton collisions and follows the trend established by measurements at lower energy. The increase of dNch/dη as a function of the average number of participant nucleons, ⟨Npart⟩, calculated in a Glauber model, is compared with the previous measurement at √sNN=2.76 TeV. A constant factor of about 1.2 describes the increase in dNch/dη from √sNN=2.76 to 5.02 TeV for all cen…

PhysicsParticle physicsLarge Hadron Collider010308 nuclear & particles physicsGeneral Physics and Astronomy01 natural sciencesCharged particleNuclear physicsPseudorapidity0103 physical sciencesQuark–gluon plasmaImpact parameterMultiplicity (chemistry)Nuclear Experiment010306 general physicsNucleonGlauberPhysical Review Letters
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Azimuthal anisotropy of charged jet production in sNN=2.76 TeV Pb–Pb collisions

2016

We present measurements of the azimuthal dependence of charged jet production in central and semicentral √sNN = 2.76 TeV Pb–Pb collisions with respect to the second harmonic event plane, quantified as vch jet 2 . Jet finding is performed employing the anti-kT algorithm with a resolution parameter R = 0.2 using charged tracks from the ALICE tracking system. The contribution of the azimuthal anisotropy of the underlying event is taken into account event-by-event. The remaining (statistical) region-to-region fluctuations are removed on an ensemble basis by unfolding the jet spectra for different event plane orientations independently. Significant non-zero vch jet 2 is observed in semi-central …

Quantum chromodynamicsPhysicsNuclear and High Energy PhysicsJet (fluid)Particle physics010308 nuclear & particles physicsAstrophysics::High Energy Astrophysical Phenomena01 natural sciencesCharged particleNuclear physics0103 physical sciencesQuark–gluon plasmaHigh Energy Physics::ExperimentNuclear Experiment010306 general physicsAnisotropyParton showerEvent (particle physics)Event generatorPhysics Letters B
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Amplitude analysis ofB+→J/ψϕK+decays

2017

The first full amplitude analysis of B+→J/ψϕK+ with J/ψ→μ+μ−, ϕ→K+K− decays is performed with a data sample of 3 fb−1 of pp collision data collected at s√=7 and 8 TeV with the LHCb detector. The data cannot be described by a model that contains only excited kaon states decaying into ϕK+, and four J/ψϕ structures are observed, each with significance over 5 standard deviations. The quantum numbers of these structures are determined with significance of at least 4 standard deviations. The lightest is best described as a D±sD∗∓s cusp, but a resonant interpretation is also possible with mass consistent with, but width much larger than, previous measurements of the claimed X(4140) state. The mode…

Cusp (singularity)PhysicsParticle physics010308 nuclear & particles physicsState (functional analysis)Quantum number01 natural sciencesStandard deviationNuclear physicsAmplitudeExcited state0103 physical sciencesHigh Energy Physics::Experiment010306 general physicsSpin-½Physical Review D
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Coherent ψ(2S) photo-production in ultra-peripheral Pb Pb collisions at sNN=2.76 TeV

2015

We have performed the first measurement of the coherent ψ(2S) photo-production cross section in ultraperipheral Pb–Pb collisions at the LHC. This charmonium excited state is reconstructed via the ψ(2S) → l +l − and ψ(2S) → J/ψπ+π− decays, where the J/ψ decays into two leptons. The analysis is based on an event sample corresponding to an integrated luminosity of about 22 μb−1. The cross section for coherent ψ(2S) production in the rapidity interval −0.9 < y < 0.9 is dσcoh ψ(2S)/dy = 0.83±0.19 stat+syst mb. The ψ(2S) to J/ψ coherent cross section ratio is 0.34+0.08 −0.07(stat + syst). The obtained results are compared to predictions from theoretical models.

Nuclear physicsPhysicsNuclear and High Energy PhysicsParticle physicsMesonBranching fractionHadronRapidityWave function7. Clean energyGlauberParticle identificationCrystal BallPhysics Letters B
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Suppression of ϒ(1S) at forward rapidity in Pb–Pb collisions at sNN=2.76 TeV

2014

We report on the measurement of the inclusive Υ (1S) production in Pb–Pb collisions at √sNN = 2.76 TeV carried out at forward rapidity (2.5 < y < 4) and down to zero transverse momentum using its μ+μ− decay channel with the ALICE detector at the Large Hadron Collider. A strong suppression of the inclusive Υ (1S) yield is observed with respect to pp collisions scaled by the number of independent nucleon– nucleon collisions. The nuclear modification factor, for events in the 0–90% centrality range, amounts to 0.30 ± 0.05(stat) ± 0.04(syst). The observed Υ (1S) suppression tends to increase with the centrality of the collision and seems more pronounced than in corresponding mid-rapidity measur…

PhysicsNuclear physicsNuclear and High Energy PhysicsRange (particle radiation)Large Hadron ColliderQuark–gluon plasmaTransverse momentumHigh Energy Physics::ExperimentModification factorRapidityNuclear ExperimentNucleonPhysics Letters B
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Measurement of jet suppression in central Pb–Pb collisions at sNN=2.76 TeV

2015

The transverse momentum(p(T)) spectrum and nuclear modification factor (R-AA) of reconstructed jets in 0-10% and 10-30% central Pb-Pb collisions at root s(NN) = 2.76 TeV were measured. Jets were reconstructed using the anti-k(T) jet algorithm with a resolution parameter of R = 0.2 from charged and neutral particles, utilizing the ALICE tracking detectors and Electromagnetic Calorimeter (EMCal). The jet p(T) spectra are reported in the pseudorapidity interval of \eta(jet)\ 5 GeV/c to suppress jets constructed from the combinatorial background in Pb-Pb collisions. The leading charged particle requirement applied to jet spectra both in pp and Pb-Pb collisions had a negligible effect on the R-A…

PhysicsNuclear and High Energy PhysicsParticle physicsJet (fluid)Large Hadron ColliderAstrophysics::High Energy Astrophysical PhenomenaSpectral lineCharged particleNuclear physicsPseudorapidityHigh Energy Physics::ExperimentRapidityNuclear ExperimentJet quenchingNeutral particlePhysics Letters B
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Centrality evolution of the charged-particle pseudorapidity density over a broad pseudorapidity range in Pb–Pb collisions at sNN=2.76 TeV

2016

State Committee of Science, World Federation of Scientists (WFS) and Swiss Fonds Kidagan, Armenia; Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq), Financiadora de Estudos e Projetos (FINEP), Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP); National Natural Science Foundation of China (NSFC), the Chinese Ministry of Education (CMOE) and the Ministry of Science and Technology of China (MSTC); Ministry of Education and Youth of the Czech Republic; Danish Natural Science Research Council, the Carlsberg Foundation and the Danish National Research Foundation; The European Research Council under the European Community's Seventh Framework Programme; Helsinki Inst…

PhysicsNuclear and High Energy PhysicsLatin AmericansHigher educationEuropean community010308 nuclear & particles physicsbusiness.industryAtomic energyEuropean researchIndustrial researchLibrary science01 natural sciences7. Clean energyBildungNuclear physics0103 physical sciences010306 general physicsChinabusinessPhysics Letters B
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Measurement of an Excess in the Yield ofJ/ψat Very LowpTin Pb–Pb Collisions atsNN=2.76  TeV

2016

We report on the first measurement of an excess in the yield of J/ψ at very low transverse momentum (pT< 0.3 GeV/c) in peripheral hadronic Pb-Pb collisions at √sNN = 2.76 TeV, performed by ALICE at the CERN LHC. Remarkably, the measured nuclear modification factor of J/ψ in the rapidity range 2.5< y< 4 reaches about 7 (2) in the pT range 0- 0.3 GeV/c in the 70-90% (50-70%) centrality class. The J/ψ production cross section associated with the observed excess is obtained under the hypothesis that coherent photoproduction of J/ψ is the underlying physics mechanism. If confirmed, the observation of J/ψ coherent photoproduction in Pb-Pb collisions at impact parameters smaller than twice the nuc…

Nuclear reactionPhysicsParticle physics010308 nuclear & particles physicsBranching fractionNuclear TheoryHadronGeneral Physics and AstronomyQuarkonium01 natural sciences7. Clean energyNuclear physics13. Climate action0103 physical sciencesQuark–gluon plasmaHigh Energy Physics::ExperimentRapidityImpact parameterNuclear Experiment010306 general physicsGlauberPhysical Review Letters
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Observation of Bc+→J/ψD(*)K(*) decays

2017

A search for the decays B + c → J / ψ D ( * ) 0 K + and B + c → J / ψ D ( * ) + K * 0 is performed with data collected at the LHCb experiment corresponding to an integrated luminosity of 3     fb − 1 . The decays B + c → J / ψ D 0 K + and B + c → J / ψ D * 0 K + are observed for the first time, while first evidence is reported for the B + c → J / ψ D * + K * 0 and B + c → J / ψ D + K * 0 decays. The branching fractions of these decays are determined relative to the B + c → J / ψ π + decay. The B + c mass is measured, using the J / ψ D 0 K + final state, to be 6274.28 ± 1.40 ( stat ) ± 0.32 ( syst )     MeV / c 2 . This is the most precise single measurement of the B + c mass to date.

PhysicsNuclear magnetic resonanceMeson010308 nuclear & particles physicsBranching fractionGenerator (category theory)0103 physical sciencesSingle measurementAnalytical chemistry010306 general physics01 natural sciencesLuminosityPhysical Review D
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Event-shape engineering for inclusive spectra and elliptic flow in Pb-Pb collisions atsNN=2.76TeV

2016

We report on results obtained with the event-shape engineering technique applied to Pb-Pb collisions at √sNN=2.76 TeV. By selecting events in the same centrality interval, but with very different average flow, different initial-state conditions can be studied. We find the effect of the event-shape selection on the elliptic flow coefficient v2 to be almost independent of transverse momentum pT, which is as expected if this effect is attributable to fluctuations in the initial geometry of the system. Charged-hadron, -pion, -kaon, and -proton transverse momentum distributions are found to be harder in events with higher-than-average elliptic flow, indicating an interplay between radial and ell…

PhysicsParticle physicsProton010308 nuclear & particles physicsHadronElliptic flowParton01 natural sciencesNuclear physicsPionFlow (mathematics)0103 physical sciencesRapidityNuclear Experiment010306 general physicsGlauberPhysical Review C
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Production of inclusive ϒ(1S) and ϒ(2S) in p–Pb collisions at sNN=5.02 TeV

2015

We report on the production of inclusive Y{hooktop}(1S) and Y{hooktop}(2S) in p-Pb collisions at √sNN=5.02 TeV at the LHC. The measurement is performed with the ALICE detector at backward (-4.46<ycms<-2.96) and forward (2.03<ycms<3.53) rapidity down to zero transverse momentum. The production cross sections of the Y{hooktop}(1S) and Y{hooktop}(2S) are presented, as well as the nuclear modification factor and the ratio of the forward to backward yields of Y{hooktop}(1S). A suppression of the inclusive Y{hooktop}(1S) yield in p-Pb collisions with respect to the yield from pp collisions scaled by the number of binary nucleon-nucleon collisions is observed at forward rapidity but not at backwar…

Quantum chromodynamicsNuclear physicsPhysicsNuclear and High Energy PhysicsLarge Hadron ColliderYield (chemistry)Transverse momentumBinary numberProduction (computer science)RapidityNuclear Experiment7. Clean energyColor-glass condensatePhysics Letters B
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K*(892)0 and ϕ(1020) meson production at high transverse momentum in pp and Pb-Pb collisions at sNN=2.76 TeV

2017

The yields of the K*(892)(0) and phi(1020) resonances are measured in Pb-Pb collisions at root s(NN) = 2.76 TeV through their hadronic decays using the ALICE detector. The measurements are performed in multiple centrality intervals at mid-rapidity (vertical bar y vertical bar <0.5) in the transverse-momentum ranges 0.3 <p(T) <5 GeV/c for the K*(892)(0) and 0.5 <p(T) <5 GeV/c for the phi(1020). The yields of K*(892)(0) are suppressed in central Pb-Pb collisions with respect to pp and peripheral Pb-Pb collisions (perhaps due to rescattering of its decay products in the hadronic medium), while the longer-lived phi(1020) meson is not suppressed. These particles are also used as probes to study …

Quantum chromodynamicsPhysicsQuarkNuclear and High Energy PhysicsParticle physicsLarge Hadron ColliderLuminosity (scattering theory)Meson010308 nuclear & particles physicsNuclear TheoryHadronLambda01 natural sciencesSpectral lineNuclear physicsPionYield (chemistry)Quark–gluon plasma0103 physical sciencesParticleHigh Energy Physics::ExperimentRapidityNuclear Experiment010306 general physicsPhysical Review C
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Correlated Event-by-Event Fluctuations of Flow Harmonics in Pb-Pb Collisions at sNN=2.76  TeV

2016

We report the measurements of correlations between event-by-event fluctuations of amplitudes of anisotropic flow harmonics in nucleus-nucleus collisions, obtained for the first time using a new analysis method based on multiparticle cumulants in mixed harmonics. This novel method is robust against systematic biases originating from non-flow effects and by construction any dependence on symmetry planes is eliminated. We demonstrate that correlations of flow harmonics exhibit a better sensitivity to medium properties than the individual flow harmonics. The new measurements are performed in Pb-Pb collisions at the centre-of-mass energy per nucleon pair of $\sqrt{s_{_{\rm NN}}}=2.76$ TeV by the…

PhysicsLarge Hadron Collider010308 nuclear & particles physicsElliptic flowGeneral Physics and Astronomy01 natural sciencesHarmonic analysisNuclear physicsFlow (mathematics)Harmonics0103 physical sciencesQuark–gluon plasmaImpact parameterNuclear Experiment010306 general physicsEnergy (signal processing)Physical Review Letters
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Centrality dependence of particle production inp−Pbcollisions atsNN=5.02TeV

2015

We report measurements of the primary charged-particle pseudorapidity density and transverse momentum distributions in p-Pb collisions at root s(NN) = 5.02 TeV and investigate their correlation with experimental observables sensitive to the centrality of the collision. Centrality classes are defined by using different event-activity estimators, i.e., charged-particle multiplicities measured in three different pseudorapidity regions as well as the energy measured at beam rapidity (zero degree). The procedures to determine the centrality, quantified by the number of participants (N-part) or the number of nucleon-nucleon binary collisions (N-coll) are described. We show that, in contrast to Pb…

PhysicsNuclear and High Energy PhysicsParticle physicsLarge Hadron Collider010308 nuclear & particles physicsHadronMultiplicity (mathematics)16. Peace & justice01 natural sciencesNuclear physicsPseudorapidity0103 physical sciencesRapidityNuclear Experiment010306 general physicsNucleonCentralityEvent generatorPhysical Review C
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Centrality dependence of the nuclear modification factor of charged pions, kaons, and protons in Pb-Pb collisions atsNN=2.76TeV

2016

Transverse momentum (pT) spectra of pions, kaons, and protons up to pT=20GeV/c have been measured in Pb-Pb collisions at √sNN=2.76TeV using the ALICE detector for six different centrality classes covering 0%–80%. The proton-to-pion and the kaon-to-pion ratios both show a distinct peak at pT≈3GeV/c in central Pb-Pb collisions that decreases for more peripheral collisions. For pT>10GeV/c, the nuclear modification factor is found to be the same for all three particle species in each centrality interval within systematic uncertainties of 10%–20%. This suggests there is no direct interplay between the energy loss in the medium and the particle species composition in the hard core of the quenched…

PhysicsSemileptonic decayParticle physics010308 nuclear & particles physicsNuclear TheoryHadron01 natural sciencesCharged particleParticle identificationBaryonNuclear physicsPion0103 physical sciencesQuark–gluon plasmaHigh Energy Physics::ExperimentNuclear Experiment010306 general physicsJet quenchingPhysical Review C
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