95 research outputs found
(KsKs0)-K-0 correlations in pp collisions at root s=7 TeV from the LHC ALICE experiment
No full textIdentical neutral kaon pair correlations are measured in root s = 7 TeV pp collisions in the ALICE experiment. One-dimensional (KsKs0)-K-0 correlation functions in terms of the invariant momentum difference of kaon pairs are formed in two multiplicity and two transverse momentum ranges. The femtoscopic parameters for the radius and correlation strength of the kaon source are extracted. The fit includes quantum statistics and final-state interactions of the a(0)/f(0) resonance. (KsKs0)-K-0 correlations show an increase in radius for increasing multiplicity and a slight decrease in radius for increasing transverse mass, mT, as seen in pi pi correlations in pp collisions and in heavy-ion collisions. Transverse mass scaling is observed between the (KsKs0)-K-0 and pi pi radii. Also, the first observation is made of the decay of the f(2)'(1525) meson into the (KsKs0)-K-0 channel in pp collisions. (C) 2012 CERN. Published by Elsevier B.V. All rights reserved.AuthorOverflow(989
Measurement of charm production at central rapidity in proton-proton collisions at ps = 7 TeV
No full textThe p t-differential inclusive production cross sections of the prompt charmed mesons D0, D+, and D*+ in the rapidity range |y| < 0.5 were measured in proton-proton collisions at Ös = 7 TeVs=7TeV at the LHC using the ALICE detector. Reconstructing the decays D0 → K−π+, D+ → K−π+π+, D*+ → D0π+, and their charge conjugates, about 8,400 D0, 2,900 D+, and 2,600 D*+ mesons with 1 < p t < 24 GeV/c were counted, after selection cuts, in a data sample of 3.14 × 108 events collected with a minimum-bias trigger (integrated luminosity L int = 5 nb−1). The results are described within uncertainties by predictions based on perturbative QCD
Measurement of charm production at central rapidity in proton-proton collisions at root s=7 TeV [Elektronisk resurs]
No full textThe p(t)-differential inclusive production cross sections of the prompt charmed mesons D-0, D+, and D*(+) in the rapidity range vertical bar y vertical bar K-pi(+), D+ -> K-pi(+)pi(+), D*(+) -> D-0 pi(+), and their charge conjugates, about 8,400 D-0, 2,900 D+, and 2,600 D*(+) mesons with 1 < p(t) < 24 GeV/c were counted, after selection cuts, in a data sample of 3.14 x 10(8) events collected with a minimum-bias trigger (integrated luminosity L-int = 5 nb(-1)). The results are described within uncertainties by predictions based on perturbative QCD.AuthorOverflow(962
Measurement of charm production at central rapidity in proton-proton collisions at = 7 TeV
No full textThe pt-differential inclusive production cross sections of the prompt charmed mesons D0, D+, and D*+ in the rapidity range |y|K-pi+, D+->K-pi+pi+, D*+->D0pi+, and their charge conjugates, about 8,400 D0, 2,900 D+, and 2,600 D*+ mesons with 1<pt<24 GeV/c were counted, after selection cuts, in a data sample of 3.14x10^8 events collected with a minimum-bias trigger (integrated luminosity L_int = 5/nb). The results are described within uncertainties by predictions based on perturbative QCD.The -differential inclusive production cross sections of the prompt charmed mesons , , and in the rapidity range |y|<0.5 were measured in proton-proton collisions at TeV at the LHC using the ALICE detector. Reconstructing the decays , , , and their charge conjugates, about 8,400 , 2,900 , and 2,600 mesons with 1<<24 GeV/ were counted, after selection cuts, in a data sample of 3.14x10 events collected with a minimum-bias trigger (integrated luminosity = 5/nb). The results are described within uncertainties by predictions based on perturbative QCD
Measurement of event background fluctuations for charged particle jet reconstruction in Pb-Pb collisions at √sNN =2.76 TeV
No full textThe effect of event background fluctuations on charged particle jet reconstruction in Pb-Pb collisions at √sNN = 2.76 has been measured with the ALICE experiment. The main sources of non-statistical fluctuations are characterized based purely on experimental data with an unbiased method, as well as by using single high p t particles and simulated jets embedded into real Pb-Pb events and reconstructed with the anti-k t jet finder. The influence of a low transverse momentum cut-off on particles used in the jet reconstruction is quantified by varying the minimum track p t between 0.15 GeV/c and 2 GeV/c. For embedded jets reconstructed from charged particles with p t > 0.15 GeV/c, the uncertainty in the reconstructed jet transverse momentum due to the heavy-ion background is measured to be 11.3 GeV/c (standard deviation) for the 10% most central Pb-Pb collisions, slightly larger than the value of 11.0 GeV/c measured using the unbiased method. For a higher particle transverse momentum threshold of 2 GeV/c, which will generate a stronger bias towards hard fragmentation in the jet finding process, the standard deviation of the fluctuations in the reconstructed jet transverse momentum is reduced to 4.8-5.0 GeV/c for the 10% most central events. A non-Gaussian tail of the momentum uncertainty is observed and its impact on the reconstructed jet spectrum is evaluated for varying particle momentum thresholds, by folding the measured fluctuations with steeply falling spectra
Measurement of charm production at central rapidity in proton-proton collisions at square s = 2.76 TeV
No full textThe p(t)-differential production cross sections of the prompt (B feed-down subtracted) charmed mesons D-0, D+, and D*(+) in the rapidity range vertical bar y vertical bar < 0.5, and for transverse momentum 1 < p(t) < 12 GeV/c, were measured in proton-proton collisions at root s = 2.76 TeV with the ALICE detector at the Large Hadron Collider. The analysis exploited the hadronic decays D-0 -> K-pi(+), D+ -> K-pi(+)pi(+), D*(+) -> D-0 pi(+), and their charge conjugates, and was performed on a L-int = 1.1 nb(-1) event sample collected in 2011 with a minimum-bias trigger. The total charm production cross section at root s = 2.76 TeV and our previous measurements at root s = 7 TeV. The results were compared to existing measurements and to perturbative-QCD calculations. The fraction of c(d)over-bar D mesons produced in a vector state was also determined
Measurement of charm production at central rapidity in proton-proton collisions at root s=7 TeV
No full textThe p(t)-differential inclusive production cross sections of the prompt charmed mesons D-0, D+, and D*(+) in the rapidity range vertical bar y vertical bar < 0.5 were measured in proton-proton collisions at root s = 7 TeV at the LHC using the ALICE detector. Reconstructing the decays D-0 -> K-pi(+), D+ -> K-pi(+)pi(+), D*(+) -> D-0 pi(+), and their charge conjugates, about 8,400 D-0, 2,900 D+, and 2,600 D*(+) mesons with 1 < p(t) < 24 GeV/c were counted, after selection cuts, in a data sample of 3.14 x 10(8) events collected with a minimum-bias trigger (integrated luminosity L-int = 5 nb(-1)). The results are described within uncertainties by predictions based on perturbative QCD
Pion, Kaon, and Proton Production in Central Pb-Pb Collisions at √sNN=2.76 TeV
No full textIn this Letter we report the first results on π±, K±, p, and p̅ production at midrapidity (|y|<0.5) in central Pb-Pb collisions at √sNN=2.76 TeV, measured by the ALICE experiment at the LHC. The pT distributions and yields are compared to previous results at √sNN=200 GeV and expectations from hydrodynamic and thermal models. The spectral shapes indicate a strong increase of the radial flow velocity with √sNN, which in hydrodynamic models is expected as a consequence of the increasing particle density. While the K/π ratio is in line with predictions from the thermal model, the p/π ratio is found to be lower by a factor of about 1.5. This deviation from thermal model expectations is still to be understood
Measurement of charm production at central rapidity in proton-proton collisions at = 2.76 TeV
No full textThe pt-differential production cross sections of the prompt (B feed-down subtracted) charmed mesons D0, D+, and D*+ in the rapidity range |y| K- pi+, D+ -> K- pi+ pi+, D*+ -> D0 pi+, and their charge conjugates, and was performed on a L_int = 1.1 nb^-1 event sample collected in 2011 with a minimum-bias trigger. The total charm production cross section at sqrt(s)= 2.76 TeV and at 7 TeV was evaluated by extrapolating to the full phase space the pt-differential production cross sections at sqrt(s) = 2.76 TeV and our previous measurements at sqrt(s) = 7 TeV. The results were compared to existing measurements and to perturbative-QCD calculations. The fraction of c dbar D mesons produced in a vector state was also determined.The -differential production cross sections of the prompt (B feed-down subtracted) charmed mesons D, D, and D in the rapidity range , and for transverse momentum GeV/, were measured in proton-proton collisions at TeV with the ALICE detector at the Large Hadron Collider. The analysis exploited the hadronic decays DK, DK, DD, and their charge conjugates, and was performed on a nb event sample collected in 2011 with a minimum-bias trigger. The total charm production cross section at TeV and at 7 TeV was evaluated by extrapolating to the full phase space the -differential production cross sections at TeV and our previous measurements at TeV. The results were compared to existing measurements and to perturbative-QCD calculations. The fraction of cdbar D mesons produced in a vector state was also determined
Measurement of charm production at central rapidity in proton-proton collisions at root s=7 TeV
No full textConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)The p(t)-differential inclusive production cross sections of the prompt charmed mesons D-0, D+, and D*(+) in the rapidity range vertical bar y vertical bar K-pi(+), D+ -> K-pi(+)pi(+), D*(+) -> D-0 pi(+), and their charge conjugates, about 8,400 D-0, 2,900 D+, and 2,600 D*(+) mesons with 1 < p(t) < 24 GeV/c were counted, after selection cuts, in a data sample of 3.14 x 10(8) events collected with a minimum-bias trigger (integrated luminosity L-int = 5 nb(-1)). The results are described within uncertainties by predictions based on perturbative QCD.1Department of Science and Technology, South AfricaCalouste Gulbenkian Foundation from LisbonSwiss Fonds Kidagan, ArmeniaConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Financiadora de Estudos e Projetos (FINEP)National Natural Science Foundation of China (NSFC)Chinese Ministry of Education (CMOE)Ministry of Science and Technology of China (MSTC)Ministry of Education and Youth of the Czech RepublicDanish Natural Science Research CouncilCarlsberg FoundationDanish National Research FoundationThe European Research Council under the European CommunityHelsinki Institute of PhysicsAcademy of FinlandFrench CNRS-IN2P3Region Pays de LoireRegion AlsaceRegion AuvergneCEA, FranceGerman BMBFHelmholtz AssociationGeneral Secretariat for Research and Technology, Ministry of Development, GreeceHungarian OTKANational Office for Research and Technology (NKTH)Department of Atomic EnergyDepartment of Science and Technology of the Government of IndiaIstituto Nazionale di Fisica Nucleare (INFN) of ItalyMEXT, JapanJoint Institute for Nuclear Research, DubnaNational Research Foundation of Korea (NRF)CONACYTDGAPA, MexicoALFA-ECHELEN (High-Energy physics Latin-American-European Network)Stichting voor Fundamenteel Onderzoek der Materie (FOM)Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO), NetherlandsResearch Council of Norway (NFR)Polish Ministry of Science and Higher EducationNational Authority for Scientific Research - NASR (Autoritatea Nationala pentru Cercetare Stiintifica - ANCS)Federal Agency of Science of the Ministry of Education and Science of Russian FederationInternational Science and Technology CenterRussian Academy of SciencesRussian Federal Agency of Atomic EnergyRussian Federal Agency for Science and InnovationsCERN-INTASMinistry of Education of SlovakiaCIEMATEELAMinisterio de Educacion y Ciencia of SpainXunta de Galicia (Conselleria de Educacion)CEADENCubaenergiaCubaIAEA (International Atomic Energy Agency)Swedish Reseach Council (VR)Knut & Alice Wallenberg Foundation (KAW)Ukraine Ministry of Education and ScienceUnited Kingdom Science and Technology Facilities Council (STFC)The United States Department of EnergyUnited States National Science FoundationState of TexasState of OhioFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP
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