0000000000603243

AUTHOR

N. Willis

showing 8 related works from this author

Production ofωmesons inp+p,d+ Au, Cu + Cu, and Au + Au collisions atsNN=200GeV

2011

The PHENIX experiment at the Relativistic Heavy Ion Collider has measured omega meson production via leptonic and hadronic decay channels in p + p, d + Au, Cu+ Cu, and Au + Au collisions at root s(NN) = 200 GeV. The invariant transverse momentum spectra measured in different decay modes give consistent results. Measurements in the hadronic decay channel in Cu Cu and Au + Au collisions show that. production has a suppression pattern at high transverse momentum, similar to that of pi(0) and eta in central collisions, but no suppression is observed in peripheral collisions. The nuclear modification factors, R-AA, are consistent in Cu + Cu and Au + Au collisions at similar numbers of participan…

PhysicsNuclear and High Energy PhysicsQuantitative Biology::Neurons and CognitionMeson010308 nuclear & particles physicsNuclear Theorychemistry.chemical_element01 natural sciencesOmegaCopperSpectral lineNuclear physicsDeuteriumchemistry0103 physical sciencesTransverse momentumHigh Energy Physics::ExperimentAtomic physicsNuclear Experiment010306 general physicsNucleonRelativistic Heavy Ion ColliderPhysical Review C
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Alignment of the ALICE Inner Tracking System with cosmic-ray tracks

2010

ALICE (A Large Ion Collider Experiment) is the LHC (Large Hadron Collider) experiment devoted to investigating the strongly interacting matter created in nucleus-nucleus collisions at the LHC energies. The ALICE ITS, Inner Tracking System, consists of six cylindrical layers of silicon detectors with three different technologies; in the outward direction: two layers of pixel detectors, two layers each of drift, and strip detectors. The number of parameters to be determined in the spatial alignment of the 2198 sensor modules of the ITS is about 13,000. The target alignment precision is well below 10 micron in some cases (pixels). The sources of alignment information include survey measurement…

Physics - Instrumentation and DetectorsPhysics::Instrumentation and DetectorsperspectiveHigh Energy PhisicsDetector alignment and calibration methods (lasers sources particle-beams); Particle tracking detectors (Solid-state detectors); Instrumentation; Mathematical Physics01 natural sciences7. Clean energylaw.inventionHigh Energy Physics - ExperimentHigh Energy Physics - Experiment (hep-ex)lawParticle tracking detectors[PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex]Tracking detectors; High Energy Phisics; Heavy Ion PhysicsDetectors and Experimental TechniquesDetector alignment and calibration methodsNuclear ExperimentInstrumentationphysics.ins-detMathematical PhysicsdetectorsPhysicsLarge Hadron ColliderSolenoidal vector fieldPhysicsDetectorInstrumentation and Detectors (physics.ins-det)particle-beams)collisionsParticle tracking detectors (Solid-state detectors) ; Detector alignment and calibration methods (lasers ; sources ; particle-beams)collaboration; collisions; detector alignment and calibration methods (lasers; sources; particle-beams); detectors; particle tracking detectors (solid-state detectors); performance; perspective; quark-gluon plasmaColliding beam accelerators collisions Pb-Pb collisionsParticle tracking detectors (Solid-state detectors); Detector alignment and calibration methods (lasers sources particle-beams); QUARK-GLUON PLASMAperformancesourcesquark-gluon plasmaDetector alignment and calibration methodFOS: Physical sciencesCosmic ray114 Physical sciencesNuclear physicsTracking detectorsOpticsparticle tracking detectors (solid-state detectors)0103 physical sciences[PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det]010306 general physicsColliderPixel010308 nuclear & particles physicsbusiness.industryhep-exHeavy Ion Physicsdetector alignment and calibration methods (laserscollaborationQuark–gluon plasmaDetector alignment and calibration methods; Particle tracking detectorsALICE (propellant)business
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Direct photon production ind+Au collisions atsNN=200GeV

2013

Direct photons have been measured in root s(NN) = 200 GeV d + Au collisions at midrapidity. A wide p(T) range is covered by measurements of nearly real virtual photons (1 < p(T) < 6 GeV/c) and real photons (5 < p(T) < 16 GeV/c). The invariant yield of the direct photons in d + Au collisions over the scaled p + p cross section is consistent with unity. Theoretical calculations assuming standard cold-nuclear-matter effects describe the data well for the entire p(T) range. This indicates that the large enhancement of direct photons observed in Au + Au collisions for 1.0 < p(T) < 2.5 GeV/c is attributable to a source other than the initial-state nuclear effects.

PhysicsNuclear and High Energy PhysicsPhoton010308 nuclear & particles physicsVirtual particle01 natural sciences7. Clean energyPhoton yieldNuclear physics0103 physical sciencesAtomic physicsNuclear Experiment010306 general physicsRelativistic Heavy Ion ColliderPhysical Review C
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The ALICE experiment at the CERN LHC

2008

Journal of Instrumentation 3(08), S08002 (2008). doi:10.1088/1748-0221/3/08/S08002

visible and IR photonsLiquid detectorshigh energyPhotonPhysics::Instrumentation and DetectorsTransition radiation detectorsTiming detectors01 natural sciencesOverall mechanics designParticle identificationSoftware architecturesParticle identification methodsGaseous detectorscluster findingDetector cooling and thermo-stabilizationDetector groundingParticle tracking detectors[PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex]Special cablesDetector alignment and calibration methodsDetectors and Experimental TechniquesNuclear ExperimentVoltage distributions.Photon detectors for UVInstrumentationMathematical PhysicsQuantum chromodynamicsPhysicsLarge Hadron ColliderSpectrometersPhysicsDetectorcalibration and fitting methodsTransition radiation detectorScintillatorsData processing methodsAnalysis and statistical methodsData reduction methodsParticle physicsCherenkov and transition radiationTime projection chambers610dE/dx detectorsNuclear physicsCalorimetersPattern recognitionGamma detectors0103 physical sciencesddc:610Solid state detectors010306 general physicsMuonInstrumentation for heavy-ion acceleratorsSpectrometerLarge detector systems for particle and astroparticle physics010308 nuclear & particles physicsCERN; LHC; ALICE; heavy ion; QGPCherenkov detectorsComputingVoltage distributionsManufacturingscintillation and light emission processesanalysis and statistical methods; calorimeters; cherenkov and transition radiation; cherenkov detectors; computing; data processing methods; data reduction methods; de/dx detectors; detector alignment and calibration methods; detector cooling and thermo-stabilization; detector design and construction technologies and materials; detector grounding; gamma detectors; gaseous detectors; instrumentation for heavy-ion accelerators; instrumentation for particle accelerators and storage rings - high energy; large detector systems for particle and astroparticle physics; liquid detectors; manufacturing; overall mechanics design; particle identification methods; particle tracking detectors; pattern recognition; cluster finding; calibration and fitting methods; photon detectors for uv; visible and ir photons; scintillators; scintillation and light emission processes; simulation methods and programs; software architectures; solid state detectors; special cables; spectrometers; time projection chambers; timing detectors; transition radiation detectors; voltage distributionsInstrumentation for particle accelerators and storage ringsInstrumentation; Mathematical PhysicsHigh Energy Physics::ExperimentSimulation methods and programsDetector design and construction technologies and materials
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Two-pion Bose-Einstein correlations inppcollisions ats=900  GeV

2010

We report on the measurement of two-pion correlation functions from pp collisions at root s = 900 GeV performed by the ALICE experiment at the Large Hadron Collider. Our analysis shows an increase of the Hanbury Brown-Twiss radius with increasing event multiplicity, in line with other measurements done in particle- and nuclear collisions. Conversely, the strong decrease of the radius with increasing transverse momentum, as observed at the Relativistic Heavy Ion Collider and at Tevatron, is not manifest in our data.

PhysicsNuclear and High Energy PhysicsParticle physicsLarge Hadron ColliderMeson010308 nuclear & particles physicsNuclear TheoryHadronTevatronParticle acceleratorBose–Einstein correlations01 natural scienceslaw.inventionNuclear physicsPionlaw0103 physical sciencesHigh Energy Physics::ExperimentNuclear Experiment010306 general physicsRelativistic Heavy Ion ColliderPhysical Review D
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Midrapidity Antiproton-to-Proton Ratio inppCollisons ats=0.9and 7 TeV Measured by the ALICE Experiment

2010

The ratio of the yields of antiprotons to protons in pp collisions has been measured by the ALICE experiment at root s = 0.9 and 7 TeV during the initial running periods of the Large Hadron Collider. The measurement covers the transverse momentum interval 0.45 < p(t) < 1.05 GeV/c and rapidity vertical bar y vertical bar < 0.5. The ratio is measured to be R-vertical bar y vertical bar<0.5 = 0.957 +/- 0.006(stat) +/- 0.0014(syst) at 0.9 Tev and R-vertical bar y vertical bar<0.5 = 0.991 +/- 0.005 +/- 0.014(syst) at 7 TeV and it is independent of both rapidity and transverse momentum. The results are consistent with the conventional model of baryon-number transport and set stringent limits on a…

PhysicsParticle physicsLarge Hadron ColliderProton010308 nuclear & particles physicsHigh Energy Physics::PhenomenologyHadronGeneral Physics and Astronomy01 natural sciences7. Clean energyParticle identificationBaryonNuclear physicsAntiproton0103 physical sciencesHigh Energy Physics::ExperimentRapidityNuclear Experiment010306 general physicsBar (unit)Physical Review Letters
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Nuclear modification factors ofϕmesons ind+Au,Cu+Cu, andAu+Aucollisions atsNN=200 GeV

2011

The PHENIX experiment at the Relativistic Heavy Ion Collider has performed systematic measurements of phi meson production in the K+K- decay channel at midrapidity in p + p, d + Au, Cu + Cu, and Au + Au collisions at root s(NN) = 200 GeV. Results are presented on the phi invariant yield and the nuclear modification factor R-AA for Au + Au and Cu + Cu, and R-dA for d + Au collisions, studied as a function of transverse momentum (1 < p(T) < 7 GeV/c) and centrality. In central and midcentral Au + Au collisions, the R-AA of phi exhibits a suppression relative to expectations from binary scaled p + p results. The amount of suppression is smaller than that of the pi(0) and the. in the intermediat…

PhysicsNuclear and High Energy PhysicsValence (chemistry)MesonProton010308 nuclear & particles physicsHadronPhi meson01 natural sciences7. Clean energyBaryonNuclear physicsAntiproton0103 physical sciencesAtomic physicsNuclear Experiment010306 general physicsRelativistic Heavy Ion ColliderPhysical Review C
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The ALICE Collaboration

2009

The production of mesons containing strange quarks (KS, φ) and both singly and doubly strange baryons ( , , and − + +) are measured at mid-rapidity in pp collisions at √ s = 0.9 TeV with the ALICE experiment at the LHC. The results are obtained from the analysis of about 250 k minimum bias events recorded in 2009. Measurements of yields (dN/dy) and transverse momentum spectra at mid-rapidity for inelastic pp collisions are presented. For mesons, we report yields (〈dN/dy〉) of 0.184 ± 0.002(stat.) ± 0.006(syst.) for KS and 0.021 ± 0.004(stat.) ± 0.003(syst.) for φ. For baryons, we find 〈dN/dy〉 = 0.048 ± 0.001(stat.) ± 0.004(syst.) for , 0.047 ± 0.002(stat.) ± 0.005(syst.) for and 0.0101 ± 0.0…

PhysicsStrange quarkNuclear and High Energy PhysicsLarge Hadron ColliderMeson010308 nuclear & particles physics7. Clean energy01 natural sciencesSpectral lineVisual artsNuclear physicsBaryonMinimum biasTransverse momentum0103 physical sciencesHigh Energy Physics::ExperimentAstrophysics::Earth and Planetary AstrophysicsALICE (propellant)Nuclear Experiment010306 general physics
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