In this article,we briefly review the recent progress on collective flow and hydrodynamics in large and small systems at the Large Hadron Collider(LHC),which includes the following topics:extracting the QGP viscosity ...In this article,we briefly review the recent progress on collective flow and hydrodynamics in large and small systems at the Large Hadron Collider(LHC),which includes the following topics:extracting the QGP viscosity from the flow data,initial-state fluctuations and final-state correlations at 2.76 A TeV Pb-Pb collisions,correlations,and collective flow in high-energy p-Pb and p-p collisions.展开更多
Along with the running of Large Hadron Collider(LHC)located at CERN in November 2009,a large number of data samples of Bc meson have been collected and some hadronic Bc decay modes have been measured by the LHC experi...Along with the running of Large Hadron Collider(LHC)located at CERN in November 2009,a large number of data samples of Bc meson have been collected and some hadronic Bc decay modes have been measured by the LHC experiments.In view of the special and important roles of Bc meson decays playing in the heavy flavor sector,we here give a short review on the status of two body hadronic decays Bc!M1M2at both experimental and theoretical aspects.For the theoretical progresses,specifically,we will show lots of theoretical studies on two body hadronic Bcdecays involving pseudoscalar,vector,scalar,axial-vector,even tensor meson(s)in the final states by employing the perturbative QCD(pQCD)factorization approach.We will present a general analysis about the twobody hadronic decays of the heavy Bc meson and also provide some expectations for the future developments.展开更多
Using proton-proton collision data at centre-of-mass energies of and 13 TeV recorded by the LHCb experiment at the Large Hadron Collider,corresponding to an integrated luminosity of 9 fb-1,the invariant mass spectrum ...Using proton-proton collision data at centre-of-mass energies of and 13 TeV recorded by the LHCb experiment at the Large Hadron Collider,corresponding to an integrated luminosity of 9 fb-1,the invariant mass spectrum of J/ψ pairs is studied.A narrow structure around 6:9 GeV=c^2 matching the lineshape of a resonance and a broad structure just above twice the J/ψ mass are observed.The deviation of the data from nonresonant J/ψ-pair production is above five standard deviations in the mass region between 6:2 and 7:4 GeV=c^2,covering predicted masses of states composed of four charm quarks.The mass and natural width of the narrow X(6900)structure are measured assuming a Breit-Wigner lineshape.展开更多
First evidence of a structure in the J/ψΛinvariant mass distribution is obtained from an amplitude analysis of■b^(-)J/ψΛK^(-)decays.The observed structure is consistent with being due to a charmonium pentaquark w...First evidence of a structure in the J/ψΛinvariant mass distribution is obtained from an amplitude analysis of■b^(-)J/ψΛK^(-)decays.The observed structure is consistent with being due to a charmonium pentaquark with strangeness with a significance of 3.1r including systematic uncertainties and lookelsewhere effect.Its mass and width are determined to be 4458:8±2:9t4:7-1:1 MeV and 17:3±6:5t8:0-5:7 MeV,respectively,where the quoted uncertainties are statistical and systematic.The structure is also consistent with being due to two resonances.In addition,the narrow excited■^(-)states,N■(1690)and■(1820),are seen for the first time in a■b^(-)decay,and their masses and widths are measured with improved precision.The analysis is performed using pp collision data corresponding to a total integrated luminosity of 9 fb^(-1),collected with the LHCb experiment at centre-of-mass energies of 7,8 and 13 TeV.展开更多
基金supported by the NSFC and the MOST(Nos.11435001,11675004 and 2015CB856900)the Danish Council for Independent Research,Natural Sciencesthe Danish National Research Foundation(Danmarks Grundforskningsfond)
文摘In this article,we briefly review the recent progress on collective flow and hydrodynamics in large and small systems at the Large Hadron Collider(LHC),which includes the following topics:extracting the QGP viscosity from the flow data,initial-state fluctuations and final-state correlations at 2.76 A TeV Pb-Pb collisions,correlations,and collective flow in high-energy p-Pb and p-p collisions.
基金supported by the National Natural Science Foundation of China (11205072,10975074 and 11235005)
文摘Along with the running of Large Hadron Collider(LHC)located at CERN in November 2009,a large number of data samples of Bc meson have been collected and some hadronic Bc decay modes have been measured by the LHC experiments.In view of the special and important roles of Bc meson decays playing in the heavy flavor sector,we here give a short review on the status of two body hadronic decays Bc!M1M2at both experimental and theoretical aspects.For the theoretical progresses,specifically,we will show lots of theoretical studies on two body hadronic Bcdecays involving pseudoscalar,vector,scalar,axial-vector,even tensor meson(s)in the final states by employing the perturbative QCD(pQCD)factorization approach.We will present a general analysis about the twobody hadronic decays of the heavy Bc meson and also provide some expectations for the future developments.
基金support from CERNfrom the national agencies: CAPES, CNPq, FAPERJ and FINEP (Brazil)+20 种基金MOST and NSFC (China)CNRS/IN2P3 (France)BMBF, DFG and MPG (Germany)INFN (Italy)NWO (Netherlands)MNiSW and NCN (Poland)MEN/IFA (Romania)MSHE (Russia)MinECo (Spain)SNSF and SER (Switzerland)NASU (Ukraine)STFC (United Kingdom)DOE NP and NSF (USA)AvH Foundation (Germany)EPLANET, Marie Sklodowska-Curie Actions and ERC (European Union)A^(*)MIDEX, ANR, Labex P2IO and OCEVU, and Region Auvergne-Rhone-Alpes (France)Key Research Program of Frontier Sciences of CAS, CAS PIFIthe Thousand Talents Program (China)RFBR, RSF and Yandex LLC (Russia)GVA, XuntaGal and GENCAT (Spain)the Royal Society and the Leverhulme Trust (United Kingdom)。
文摘Using proton-proton collision data at centre-of-mass energies of and 13 TeV recorded by the LHCb experiment at the Large Hadron Collider,corresponding to an integrated luminosity of 9 fb-1,the invariant mass spectrum of J/ψ pairs is studied.A narrow structure around 6:9 GeV=c^2 matching the lineshape of a resonance and a broad structure just above twice the J/ψ mass are observed.The deviation of the data from nonresonant J/ψ-pair production is above five standard deviations in the mass region between 6:2 and 7:4 GeV=c^2,covering predicted masses of states composed of four charm quarks.The mass and natural width of the narrow X(6900)structure are measured assuming a Breit-Wigner lineshape.
文摘First evidence of a structure in the J/ψΛinvariant mass distribution is obtained from an amplitude analysis of■b^(-)J/ψΛK^(-)decays.The observed structure is consistent with being due to a charmonium pentaquark with strangeness with a significance of 3.1r including systematic uncertainties and lookelsewhere effect.Its mass and width are determined to be 4458:8±2:9t4:7-1:1 MeV and 17:3±6:5t8:0-5:7 MeV,respectively,where the quoted uncertainties are statistical and systematic.The structure is also consistent with being due to two resonances.In addition,the narrow excited■^(-)states,N■(1690)and■(1820),are seen for the first time in a■b^(-)decay,and their masses and widths are measured with improved precision.The analysis is performed using pp collision data corresponding to a total integrated luminosity of 9 fb^(-1),collected with the LHCb experiment at centre-of-mass energies of 7,8 and 13 TeV.
