The product of the ∧0/b （-B/0） differential production cross-section and the branching fraction of the decay ∧0/b→ J/ψ pK-（-B/0→ J/ψ-K＊（892）0）is measured as a function of the beauty hadron transverse mome...The product of the ∧0/b （-B/0） differential production cross-section and the branching fraction of the decay ∧0/b→ J/ψ pK-（-B/0→ J/ψ-K＊（892）0）is measured as a function of the beauty hadron transverse momentum, PT, and rapidity, y. The kinematic region of the measurements is pT〈20 GeV/c and 2.0 〈g〈4.5.The measurements use a data sample corresponding to an integrated luminosity of 3fb-1 collected by the LHCb detector in pp collisions at centre-of-mass energies √s=7 TeV in 2011 and √s=8 TeV in 2012. Based on previous LHCb results of the fragmentation fraction ratio,f∧0/b/fd,the branching fraction of the decay ∧0/b→ J/ψ pK-is measured to be B（∧0/b→ J/ψ pK-）=（3.17±0.04±0.07±0.34＋0.45/-0.28）×10-4,where the first uncertainty is statistical, the second is systematic, the third is due to the uncertainty on the branching fraction of the decay -B/0 →J/ψ-K＊（892）0,and the fourth is due to the knowledge of f∧0/b/fd.The sum of the asymmetries in the production and decay between ∧0/b and ∧0/bis also measured as a function of PT and y.The previously published branching fraction of ∧0/b→ J/ψ pπ-,relative to that of ∧0/b→ J/ψ pK-,is updated. The branching fractions of ∧0/b→P＋c（→ J/ψp）K-are determined.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
A search for the doubly charmed baryon ■^+cc is performed through its decay to theΛ^+c K^-π^+ final state,using proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7,8 and 13...A search for the doubly charmed baryon ■^+cc is performed through its decay to theΛ^+c K^-π^+ final state,using proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7,8 and 13 TeV.The data correspond to a total integrated luminosity of 9 fb^-1.No significant signal is observed in the mass range from 3.4 to 3.8 GeV/c^2.Upper limits are set at 95%credibility level on the ratio of the ■^+cc production cross-section times the branching fraction to that ofΛ^+c and ■^++cc baryons.The limits are determined as functions of the ■^+cc mass for different lifetime hypotheses,in the rapidity range from 2.0 to 4.5 and the transverse momentum range from 4 to 15 GeV/c.展开更多
The production of ■baryons in proton-proton collisions at a centre-of-mass energy of √s = 13 TeV is measured in the transverse-momentum range 4<pT<15GeV/c and the rapidity range2.0<y<4.5.The data used in...The production of ■baryons in proton-proton collisions at a centre-of-mass energy of √s = 13 TeV is measured in the transverse-momentum range 4<pT<15GeV/c and the rapidity range2.0<y<4.5.The data used in this measurement correspond to an integrated luminosity of 1.7fb^-1,recorded by the LHCb experiment during 2016.The ratio of the ■ production cross-section times the branching fraction of the■→∧^+cK^-π^+ π^+decay relative to the prompt ∧^+c production cross-section is found to be(2.22±0.27±0.29)×10^-4,assuming the central value of the measured lifetime,where the first uncertainty is statistical and the second systematic.展开更多
The design of each component of the Multipurpose Superconducting ECR Ion Source(MS-ECRIS) has been completed and some items are ready.The magnets and the cryostat are under construction at ACCEL and the commissioning ...The design of each component of the Multipurpose Superconducting ECR Ion Source(MS-ECRIS) has been completed and some items are ready.The magnets and the cryostat are under construction at ACCEL and the commissioning is scheduled for March 2007.The mechanical have been optimized and their construction is under way;the microwave system is under refurbishment and the 65kV power supply is available and upgraded for afterglow operations.Pumping and extraction system were adapted to the EIS testbench of GSI Darmstadt.The description of each part will be given in the paper along with a schedule of the forthcoming development and experiments.展开更多
A search for the rare decay B^(0)→J/ψФis performed using Pp collision data collected with the LHCb dete-ctor at centre-of-mass energies of 7,8 and 13 TeV,corresponding to an integrated luminosity of9 fb.No signific...A search for the rare decay B^(0)→J/ψФis performed using Pp collision data collected with the LHCb dete-ctor at centre-of-mass energies of 7,8 and 13 TeV,corresponding to an integrated luminosity of9 fb.No significant signal of the decay is observed and an upper limitof 1.1x 10^(-7)at 90%confidence level is set on the branching fraction.展开更多
The first search for the doubly heavyΩ^(0)_(bc)baryon and a search for the E^(0)_(bc)baryon are performed using pp collision data collected via the LHCb experiment from 2016 to 2018 at a centre-of-mass energy of 13 T...The first search for the doubly heavyΩ^(0)_(bc)baryon and a search for the E^(0)_(bc)baryon are performed using pp collision data collected via the LHCb experiment from 2016 to 2018 at a centre-of-mass energy of 13 TeV,corresponding to an integrated luminosity of 5.2 fb^(-1).The baryons are reconstructed via their decays to Λ^(+)_(c)π^(-)and E^(+)_(c)π^(-).No significant excess is fbund for invariant masses between 6700 and 7300 MeV/c^(2),in a rapidity range from 2.0 to 4.5 and a transverse momentum range from 2 to 20 MeV/c.Upper limits are set on the ratio of the Ω^(0)_(bc)and E^(0)_(bc)production cross-section times the branching fraction to Λ^(+)_(c)π^(-)(E^(+)_(c)π^(-))relative to that of the Λ^(0)_(b)(E^(0)_(b))baryon,for different lifetime hypotheses,at 95%confidence level.The upper limits range from 0.5 x 10^(-4)to 2.5 x 10^(-4)for theΩ^(0)_(bc)→Λ^(+)_(c)π^(-)(E^(0)_(bc)→Λ^(+)_(c)π^(-))decay,and from 1.4x 10^(-3)to 6.9 x 10^(-3)for theΩ^(0)_(bc)→E^(+)_(c)π^(-)(E^(0)_(bc)→E^(+)_(c)π^(-))decay,depending on the considered mass and lifetime of theΩ^(0)_(bc)(E^(0)_(bc))baryon.展开更多
基金Supported by CERN and national agencies:CAPES,CNPq,FAPERJ and FINEP(Brazil)NSFC(China)+17 种基金CNRS/IN2P3(France)BMBF,DFG,HGF and MPG(Germany)INFN(Italy)FOM and NWO(The Netherlands)MNi SW and NCN(Poland)MEN/IFA(Romania)Min ES and FANO(Russia)Min ECo(Spain)SNSF and SER(Switzerland)NASU(Ukraine)STFC(United Kingdom)NSF(USA)supported by IN2P3(France),KIT and BMBF(Germany),INFN(Italy),NWOSURF(The Netherlands),PIC(Spain),Grid PP(United Kingdom)support from EPLANET,Marie Sk lodowska-Curie ActionsERC(European Union),Conseil général de Haute-Savoie,Labex ENIGMASS and OCEVU,RégionAuvergne(France),RFBR(Russia),Xunta GalGENCAT(Spain),Royal Society and Royal Commission for the Exhibition of 1851(United Kingdom)
文摘The product of the ∧0/b （-B/0） differential production cross-section and the branching fraction of the decay ∧0/b→ J/ψ pK-（-B/0→ J/ψ-K＊（892）0）is measured as a function of the beauty hadron transverse momentum, PT, and rapidity, y. The kinematic region of the measurements is pT〈20 GeV/c and 2.0 〈g〈4.5.The measurements use a data sample corresponding to an integrated luminosity of 3fb-1 collected by the LHCb detector in pp collisions at centre-of-mass energies √s=7 TeV in 2011 and √s=8 TeV in 2012. Based on previous LHCb results of the fragmentation fraction ratio,f∧0/b/fd,the branching fraction of the decay ∧0/b→ J/ψ pK-is measured to be B（∧0/b→ J/ψ pK-）=（3.17±0.04±0.07±0.34＋0.45/-0.28）×10-4,where the first uncertainty is statistical, the second is systematic, the third is due to the uncertainty on the branching fraction of the decay -B/0 →J/ψ-K＊（892）0,and the fourth is due to the knowledge of f∧0/b/fd.The sum of the asymmetries in the production and decay between ∧0/b and ∧0/bis also measured as a function of PT and y.The previously published branching fraction of ∧0/b→ J/ψ pπ-,relative to that of ∧0/b→ J/ψ pK-,is updated. The branching fractions of ∧0/b→P＋c（→ J/ψp）K-are determined.
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.
基金support from CERN and from the national agencies:CAPES,CNPq，FAPERJ and FINEP(Brazil)MOST and NSFC(China)+11 种基金CNRS/IN2P3(France)BMBF,DFG and MPG(Germany)INFN(Italy)KWO(Netherlands)MNiSW and NCN(Poland)MEN/IFA(Romania)MinES and FASO(Russia)MinECo(Spain)SNSF and SER(Switzerland)NASU(Ukraine)STFC(United Kingdom)NSF(USA).
文摘A search for the doubly charmed baryon ■^+cc is performed through its decay to theΛ^+c K^-π^+ final state,using proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7,8 and 13 TeV.The data correspond to a total integrated luminosity of 9 fb^-1.No significant signal is observed in the mass range from 3.4 to 3.8 GeV/c^2.Upper limits are set at 95%credibility level on the ratio of the ■^+cc production cross-section times the branching fraction to that ofΛ^+c and ■^++cc baryons.The limits are determined as functions of the ■^+cc mass for different lifetime hypotheses,in the rapidity range from 2.0 to 4.5 and the transverse momentum range from 4 to 15 GeV/c.
基金Supported by CERNnational agencies:CAPES+30 种基金CNPqFAPERJFINEP(Brazil)MOSTNSFC(China)CNRS/IN2P3(France)BMBFDFGMPG(Germany)INFN(Italy)NWO(Netherlands)MNiSWNCN(Poland)MEN/IFA(Romania)MSHE(Russia)MinECo(Spain)SNSFSER(Switzerland)NASU(Ukraine)STFC(United Kingdom)DOE NPNSF(USA)Key Research Program of Frontier Sciences of CAS,CAS PIFIthe Thousand Talents Program(China)RFBRRSFYandex LLC(Russia)GVAXuntaGalGENCAT(Spain)the Royal Society and the Leverhulme Trust(United Kingdom)
文摘The production of ■baryons in proton-proton collisions at a centre-of-mass energy of √s = 13 TeV is measured in the transverse-momentum range 4<pT<15GeV/c and the rapidity range2.0<y<4.5.The data used in this measurement correspond to an integrated luminosity of 1.7fb^-1,recorded by the LHCb experiment during 2016.The ratio of the ■ production cross-section times the branching fraction of the■→∧^+cK^-π^+ π^+decay relative to the prompt ∧^+c production cross-section is found to be(2.22±0.27±0.29)×10^-4,assuming the central value of the measured lifetime,where the first uncertainty is statistical and the second systematic.
基金Supported through EURONS (European Commission Contract no.506065)
文摘The design of each component of the Multipurpose Superconducting ECR Ion Source(MS-ECRIS) has been completed and some items are ready.The magnets and the cryostat are under construction at ACCEL and the commissioning is scheduled for March 2007.The mechanical have been optimized and their construction is under way;the microwave system is under refurbishment and the 65kV power supply is available and upgraded for afterglow operations.Pumping and extraction system were adapted to the EIS testbench of GSI Darmstadt.The description of each part will be given in the paper along with a schedule of the forthcoming development and experiments.
基金support from AvH Foundation(Germany)EPLANET,Marie Sk lodowska-Curie Actions and ERC(European Union)+11 种基金A*MIDEXANRLabex P2IOOCEVURégion Auvergne-Rh?ne-Alpes(France)Key Research Program of Frontier Sciences of CASCAS PIFIThousand Talents ProgramSci.&Tech.Program of Guangzhou(China)RFBR,RSF and Yandex LLC(Russia)GVA,Xunta Gal and GENCAT(Spain)the Royal Society and the Leverhulme Trust(United Kingdom)。
文摘A search for the rare decay B^(0)→J/ψФis performed using Pp collision data collected with the LHCb dete-ctor at centre-of-mass energies of 7,8 and 13 TeV,corresponding to an integrated luminosity of9 fb.No significant signal of the decay is observed and an upper limitof 1.1x 10^(-7)at 90%confidence level is set on the branching fraction.
基金CAPES,CNPq,FAPERJ and FINEP(Brazil)MOST and NSFC(China)+18 种基金CNRS/IN2P3(France)BMBF,DFG,MPG(Germany)INFN(Italy)NWO(Netherlands)MNiSW,NCN(Poland)MEN/IFA(Romania)MSHE(Russia)MICINN(Spain)SNSF,SER(Switzerland)NASU(Ukraine)STFC(United Kingdom)DOE NP,NSF(USA).We acknowledge the computing resources that are provided by CERN,IN2P3(France),KIT and DESY(Germany),INFN(Italy),SURF(Netherlands),PIC(Spain),GridPP(United Kingdom),RRCKI and Yandex LLC(Russia),CSCS(Switzerland),IFIN-HH(Romania),CBPF(Brazil),PL-GRID(Poland)and NERSC(USA)AvH Foundation(Germany)EPLANET,Marie Sklodowska-Curie Actions and ERC(European Union)A*MIDEX,ANR,Labex P2IO and OCEVU,Region Auvergne-Rhdne-Alpes(France)Key Research Program of Frontier Sciences of CAS,CAS PIFI,CAS CCEPP,Fundamental Research Funds for the Central Universities,and Sci.Tech.Program of Guangzhou(China)RFBR,RSF and Yandex LLC(Russia)GVA,XuntaGal,GENCAT(Spain)the Leverhulme Trust,the Royal Society and UKRI(United Kingdom)。
文摘The first search for the doubly heavyΩ^(0)_(bc)baryon and a search for the E^(0)_(bc)baryon are performed using pp collision data collected via the LHCb experiment from 2016 to 2018 at a centre-of-mass energy of 13 TeV,corresponding to an integrated luminosity of 5.2 fb^(-1).The baryons are reconstructed via their decays to Λ^(+)_(c)π^(-)and E^(+)_(c)π^(-).No significant excess is fbund for invariant masses between 6700 and 7300 MeV/c^(2),in a rapidity range from 2.0 to 4.5 and a transverse momentum range from 2 to 20 MeV/c.Upper limits are set on the ratio of the Ω^(0)_(bc)and E^(0)_(bc)production cross-section times the branching fraction to Λ^(+)_(c)π^(-)(E^(+)_(c)π^(-))relative to that of the Λ^(0)_(b)(E^(0)_(b))baryon,for different lifetime hypotheses,at 95%confidence level.The upper limits range from 0.5 x 10^(-4)to 2.5 x 10^(-4)for theΩ^(0)_(bc)→Λ^(+)_(c)π^(-)(E^(0)_(bc)→Λ^(+)_(c)π^(-))decay,and from 1.4x 10^(-3)to 6.9 x 10^(-3)for theΩ^(0)_(bc)→E^(+)_(c)π^(-)(E^(0)_(bc)→E^(+)_(c)π^(-))decay,depending on the considered mass and lifetime of theΩ^(0)_(bc)(E^(0)_(bc))baryon.
