The experimental data concerning the58Ni+48Ca reaction at Elab(Ni)=25A MeV,collected by using the CHIMERA 4π device,have been analyzed in order to investigate the competition among different reaction mechanisms for c...The experimental data concerning the58Ni+48Ca reaction at Elab(Ni)=25A MeV,collected by using the CHIMERA 4π device,have been analyzed in order to investigate the competition among different reaction mechanisms for central collisions in the Fermi energy domain.As a main criterion for centrality selection we have chosen the flow angle(flow) method,making an event-by-event analysis that considers the shape of events,as it is determined by the eigenvectors of the experimental kinetic-energy tensor.For the selected central events(flow >60°) some global variables,good to characterize the pattern of central collisions have been constructed.The main features of the reaction products were explored by using different constraints on some of the relevant observables,like mass and velocity distributions and their correlations.Much emphasis was devoted,for central collisions,to the competition between fusion-evaporation processes with subsequent identification of a heavy residue and a possible multifragmentation mechanism of a well defined(if any) transient nuclear system.Dynamical evolution of the system and pre-equilibrium emission were taken into account by simulating the reactions in the framework of transport theories.Different approaches have been envisaged(dynamical stochastic BNV calculations + sequential SIMON code,QMD,CoMD,etc.).Preliminary comparison of the experimental data with BNV calculations shows reasonable agreement with the assumption of sequential multifragmentation emission in the mass region of IMFs close to the heavy residues.Possible deviations from sequential processes were found for those IMFs in the region of masses intermediate between the mass of heavy residues and the mass of light IMFs.Further simulations are in progress.The experimental analysis will be enriched also by information obtained inspecting the IMF-IMF correlation function,in order to elucidated the nature of space-time decay property of the emitting source associated with events having the largest IMF multiplicity.展开更多
In spiral galaxies, we explain their non-Keplerian rotation curves (RCs) by means of a non-luminous component embedding their stellar-gaseous disks. Understanding the detailed properties of this component (labelled Da...In spiral galaxies, we explain their non-Keplerian rotation curves (RCs) by means of a non-luminous component embedding their stellar-gaseous disks. Understanding the detailed properties of this component (labelled Dark Matter, DM) is one of the most pressing issues of Cosmology. We investigate the recent relationship (claimed by Walker et al. 2010, hereafter W + 10) between r, the galaxy radial coordinate, and Vh(r), the dark halo contribution to the circular velocity at r, 1) in the framework of the Universal Rotation Curve (URC) paradigm and directly 2) by means of the kinematics of a large sample of DM dominated spirals. We find a general agreement between the W + 10 claim, the distribution of DM emerging from the URC and that inferred in the (low luminosity) objects of our sample. We show that such a phenomenology, linking the spiral’s luminosity, radii and circular velocities, implies an evident inconsistency with (naive) predictions in the Λ Cold Dark Matter (ΛCDM) scenario.展开更多
We compute in a theoretical quantum field theory framework the effects that a classic environment will have on an elementary one-fermion state, assumed for simplicity to be that of one electron, in the presence of a m...We compute in a theoretical quantum field theory framework the effects that a classic environment will have on an elementary one-fermion state, assumed for simplicity to be that of one electron, in the presence of a magnetic field. We consider its total energy and its spin angular momentum as relevant observables of the state. We show that the changes of these quantities produced by the combined environmental and magnetic effects can be expressed in a simple and compact form. We obtain expressions that only depend on the values of the external environment and magnetic fields, and on the special spin features of the free fermion state. We call these effects “fermion epigenetics” and try to motivate this definition discussing possible relevant analogies with the corresponding medical treatment of epigenetics in organic cells.展开更多
I consider, in a Quantum Field Theory theoretical approach, the effects of an electromagnetic field on the components of the total angular momentum of an elementary fermion system, assuming the “minimal” form of the...I consider, in a Quantum Field Theory theoretical approach, the effects of an electromagnetic field on the components of the total angular momentum of an elementary fermion system, assuming the “minimal” form of the relative interaction. When the electromagnetic field can be treated as a classical one, these effects are particularly simple to be computed and exhibit a number of very general characteristic features in the case of a constant magnetic field. A qualitative possible analogy with similar features of an elementary organic system is finally proposed.展开更多
Measuring fluctuations in matter’s low-energy excitations is the key to unveiling the nature of the non-equilibrium response of materials.A promising outlook in this respect is offered by spectroscopic methods that a...Measuring fluctuations in matter’s low-energy excitations is the key to unveiling the nature of the non-equilibrium response of materials.A promising outlook in this respect is offered by spectroscopic methods that address matter fluctuations by exploiting the statistical nature of light-matter interactions with weak few-photon probes.Here we report the first implementation of ultrafast phase randomized tomography,combining pump-probe experiments with quantum optical state tomography,to measure the ultrafast non-equilibrium dynamics in complex materials.Our approach utilizes a time-resolved multimode heterodyne detection scheme with phase-randomized coherent ultrashort laser pulses,overcoming the limitations of phase-stable configurations and enabling a robust reconstruction of the statistical distribution of phase-averaged optical observables.This methodology is validated by measuring the coherent phonon response inα-quartz.By tracking the dynamics of the shot-noise limited photon number distribution of fewphoton probes with ultrafast resolution,our results set an upper limit to the non-classical features of phononic state inα-quartz and provide a pathway to access non-equilibrium quantum fluctuations in more complex quantum materials.展开更多
We discuss the landscape of flavor physics at the Circular Electron-Positron Collider(CEPC),based on the nominal luminosity outlined in its Technical Design Report.The CEPC is designed to operate in multiple modes to ...We discuss the landscape of flavor physics at the Circular Electron-Positron Collider(CEPC),based on the nominal luminosity outlined in its Technical Design Report.The CEPC is designed to operate in multiple modes to address a variety of tasks.At the Z pole,the expected production of 4 Tera Z bosons will provide unique and highly precise measurements of Z boson couplings,while the substantial number of boosted heavy-flavored quarks and leptons produced in clean Z decays will facilitate investigations into their flavor physics with unprecedented precision.We investigate the prospects of measuring various physics benchmarks and discuss their implications for particle theories and phenomenological models.Our studies indicate that,with its highlighted advantages and anticipated excellent detector performance,the CEPC can explore beauty andτphysics in ways that are superior to or complementary with the Belle II and Large-Hadron-Collider-beauty experiments,potentially enabling the detection of new physics at energy scales of 10 TeV and above.This potential also extends to the observation of yet-to-be-discovered rare and exotic processes,as well as testing fundamental principles such as lepton flavor universality,lepton and baryon number conservation,etc.,making the CEPC a vibrant platform for flavor physics research.The WW threshold scan,Higgs-factory operation and top-pair productions of the CEPC further enhance its merits in this regard,especially for measuring the Cabibbo-Kobayashi-Maskawa matrix elements,and Flavor-Changing-NeutralCurrent physics of Higgs boson and top quarks.We outline the requirements for detector performance and considerations for future development to achieve the anticipated scientific goals.The role of machine learning for innovative detector design and advanced reconstruction algorithms is also stressed.The CEPC flavor physics program not only develops new capabilities for exploring flavor physics beyond existing projects but also enriches the physics opportunities of this machine.It should be remarked that,given the richness of the CEPC flavor physics,this manuscript is not meant to be a comprehensive survey,but rather an investigation of representative cases.Uncovering the full potential of flavor physics at the CEPC will require further dedicated explorations in the future.展开更多
In line X-ray phase contrast micro-computed tomography （IL-XPCT）, which can be implemented at third generation synchrotron radiation sources or by using a micro-focus X-ray tube, is a powerful technique for non-dest...In line X-ray phase contrast micro-computed tomography （IL-XPCT）, which can be implemented at third generation synchrotron radiation sources or by using a micro-focus X-ray tube, is a powerful technique for non-destructive, high-resolution investigations of a broad variety of materials. At the Shanghai Synchrotron Radiation Facility （SSRF）, the X-ray Imaging and Biomedical Applications Beamline was built and started regular user operation in May 2009. Both qualitative （without phase retrieval） and quantitative （with phase retrieval） three-dimensional IL-XPCT experimental techniques have been established at the beamline IL-XPCT experiments of a test sample （plastic pipes） used to evaluate the technique, and of a biological sample （locust） at the beamline are reported. Two series of images, qualitative and quantitative, including tomographic slices and three-dimensional rendering images were obtained. In qualitative images, there is a strong edge-enhancement which leads to very clear sample contours, while in quantitative images, the edge-enhancement fades but quantitative measurement of sample＇s phase information could be achieved. The experiments demonstrate that the combination of qualitative and quantitative images is useful for biological sample studies.展开更多
In this paper we present the enhanced X-ray Timing and Polarimetry mission—eXTP. eXTP is a space science mission designed to study fundamental physics under extreme conditions of density, gravity and magnetism. The m...In this paper we present the enhanced X-ray Timing and Polarimetry mission—eXTP. eXTP is a space science mission designed to study fundamental physics under extreme conditions of density, gravity and magnetism. The mission aims at determining the equation of state of matter at supra-nuclear density, measuring effects of QED, and understanding the dynamics of matter in strong-field gravity. In addition to investigating fundamental physics, eXTP will be a very powerful observatory for astrophysics that will provide observations of unprecedented quality on a variety of galactic and extragalactic objects. In particular, its wide field monitoring capabilities will be highly instrumental to detect the electro-magnetic counterparts of gravitational wave sources.The paper provides a detailed description of:(1) the technological and technical aspects, and the expected performance of the instruments of the scientific payload;(2) the elements and functions of the mission, from the spacecraft to the ground segment.展开更多
New physics could be explored through loop effects using the precision measurements at the Circular Electron Positron Collider(CEPC)owing to its clean collision environment and high luminosity.In this paper,we focus o...New physics could be explored through loop effects using the precision measurements at the Circular Electron Positron Collider(CEPC)owing to its clean collision environment and high luminosity.In this paper,we focus on two dark matter models that involve additional electroweak fermionic multiplets.We calculate their one-loop corrections in five processes,i.e.,e^(+)e^(-)→μ^(+)μ^(-),Zh,W^(+)W^(-),ZZ,and,Zγ,and investigate the corresponding signatures at the CEPC with the projected sensitivity.We observe that the detectable parameter regions of these processes are complementary.The combined analysis shows that the mass of dark matter m_(χ^(0)_(1))in these two models can be probed up to-150GeV and-450GeV,respectively,at a 95%confidence level.展开更多
From April to July 2018,a data sample at the peak energy of the T(4 S) resonance was collected with the Belle Ⅱ detector at the SuperKEKB electron-positron collider.This is the first data sample of the Belle Ⅱ exper...From April to July 2018,a data sample at the peak energy of the T(4 S) resonance was collected with the Belle Ⅱ detector at the SuperKEKB electron-positron collider.This is the first data sample of the Belle Ⅱ experiment.Using Bhabha and digamma events,we measure the integrated luminosity of the data sample to be(496.3±0.3±3.0) pb-1,where the first uncertainty is statistical and the second is systematic.This work provides a basis for future luminosity measurements at Belle Ⅱ.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
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
文摘The experimental data concerning the58Ni+48Ca reaction at Elab(Ni)=25A MeV,collected by using the CHIMERA 4π device,have been analyzed in order to investigate the competition among different reaction mechanisms for central collisions in the Fermi energy domain.As a main criterion for centrality selection we have chosen the flow angle(flow) method,making an event-by-event analysis that considers the shape of events,as it is determined by the eigenvectors of the experimental kinetic-energy tensor.For the selected central events(flow >60°) some global variables,good to characterize the pattern of central collisions have been constructed.The main features of the reaction products were explored by using different constraints on some of the relevant observables,like mass and velocity distributions and their correlations.Much emphasis was devoted,for central collisions,to the competition between fusion-evaporation processes with subsequent identification of a heavy residue and a possible multifragmentation mechanism of a well defined(if any) transient nuclear system.Dynamical evolution of the system and pre-equilibrium emission were taken into account by simulating the reactions in the framework of transport theories.Different approaches have been envisaged(dynamical stochastic BNV calculations + sequential SIMON code,QMD,CoMD,etc.).Preliminary comparison of the experimental data with BNV calculations shows reasonable agreement with the assumption of sequential multifragmentation emission in the mass region of IMFs close to the heavy residues.Possible deviations from sequential processes were found for those IMFs in the region of masses intermediate between the mass of heavy residues and the mass of light IMFs.Further simulations are in progress.The experimental analysis will be enriched also by information obtained inspecting the IMF-IMF correlation function,in order to elucidated the nature of space-time decay property of the emitting source associated with events having the largest IMF multiplicity.
文摘In spiral galaxies, we explain their non-Keplerian rotation curves (RCs) by means of a non-luminous component embedding their stellar-gaseous disks. Understanding the detailed properties of this component (labelled Dark Matter, DM) is one of the most pressing issues of Cosmology. We investigate the recent relationship (claimed by Walker et al. 2010, hereafter W + 10) between r, the galaxy radial coordinate, and Vh(r), the dark halo contribution to the circular velocity at r, 1) in the framework of the Universal Rotation Curve (URC) paradigm and directly 2) by means of the kinematics of a large sample of DM dominated spirals. We find a general agreement between the W + 10 claim, the distribution of DM emerging from the URC and that inferred in the (low luminosity) objects of our sample. We show that such a phenomenology, linking the spiral’s luminosity, radii and circular velocities, implies an evident inconsistency with (naive) predictions in the Λ Cold Dark Matter (ΛCDM) scenario.
文摘We compute in a theoretical quantum field theory framework the effects that a classic environment will have on an elementary one-fermion state, assumed for simplicity to be that of one electron, in the presence of a magnetic field. We consider its total energy and its spin angular momentum as relevant observables of the state. We show that the changes of these quantities produced by the combined environmental and magnetic effects can be expressed in a simple and compact form. We obtain expressions that only depend on the values of the external environment and magnetic fields, and on the special spin features of the free fermion state. We call these effects “fermion epigenetics” and try to motivate this definition discussing possible relevant analogies with the corresponding medical treatment of epigenetics in organic cells.
文摘I consider, in a Quantum Field Theory theoretical approach, the effects of an electromagnetic field on the components of the total angular momentum of an elementary fermion system, assuming the “minimal” form of the relative interaction. When the electromagnetic field can be treated as a classical one, these effects are particularly simple to be computed and exhibit a number of very general characteristic features in the case of a constant magnetic field. A qualitative possible analogy with similar features of an elementary organic system is finally proposed.
基金supported by the European Research Council through the project INCEPT(grant agreement no.677488)D.F.,E.M.R.,A.M.,and G.J.acknowledge the support of the Gordon and Betty Moore Foundation through the grant(CENTQC).
文摘Measuring fluctuations in matter’s low-energy excitations is the key to unveiling the nature of the non-equilibrium response of materials.A promising outlook in this respect is offered by spectroscopic methods that address matter fluctuations by exploiting the statistical nature of light-matter interactions with weak few-photon probes.Here we report the first implementation of ultrafast phase randomized tomography,combining pump-probe experiments with quantum optical state tomography,to measure the ultrafast non-equilibrium dynamics in complex materials.Our approach utilizes a time-resolved multimode heterodyne detection scheme with phase-randomized coherent ultrashort laser pulses,overcoming the limitations of phase-stable configurations and enabling a robust reconstruction of the statistical distribution of phase-averaged optical observables.This methodology is validated by measuring the coherent phonon response inα-quartz.By tracking the dynamics of the shot-noise limited photon number distribution of fewphoton probes with ultrafast resolution,our results set an upper limit to the non-classical features of phononic state inα-quartz and provide a pathway to access non-equilibrium quantum fluctuations in more complex quantum materials.
基金financial support from the National Natural Science Foundation of China(NSFC)(12125507,12047503,12035008,2211530479,12475094,12135006,12075097,12375086,2022YFA1601903,12061141007,12375091,12342502,12235018,12335003,12105100,12475106,11961141015,12188102,12175245,12205171,12321005,tsqn202312052,2024HWYQ-005,12405121,12447167,12061141006,12405102,12125503,12305115,12075213,12335005,12235008)the Chinese Academy of Sciences(YSBR-101,XDB34030000)+11 种基金the National Key R&D Program of China(2022YFE0116900,2023YFA1606703,2022YFA1601901)the National Key Research and Development Program of China(2023YFA1606300)the Excellent Postdoctoral Program of Jiangsu Province(2023ZB891)the Shenzhen Science and Technology Program(202206193000001,20220816094256002)the Natural Science Foundation for Distinguished Young Scholars of Henan Province(242300421046)the Beijing Municipal Natural Science Foundation(JQ22002)the Area of Excellence(AoE/P-404/18-3)the General Research Fund(16304321)(both grants are issued by the Research Grants Council of Hong Kong S.A.R)the MOST National Key R&D Program(2023YFA1606303)the Shanghai Key Laboratory for Particle Physics and CosmologyKey Laboratory for Particle Astrophysics and Cosmology(Ministry of Education)Shanghai Jiao Tong University。
文摘We discuss the landscape of flavor physics at the Circular Electron-Positron Collider(CEPC),based on the nominal luminosity outlined in its Technical Design Report.The CEPC is designed to operate in multiple modes to address a variety of tasks.At the Z pole,the expected production of 4 Tera Z bosons will provide unique and highly precise measurements of Z boson couplings,while the substantial number of boosted heavy-flavored quarks and leptons produced in clean Z decays will facilitate investigations into their flavor physics with unprecedented precision.We investigate the prospects of measuring various physics benchmarks and discuss their implications for particle theories and phenomenological models.Our studies indicate that,with its highlighted advantages and anticipated excellent detector performance,the CEPC can explore beauty andτphysics in ways that are superior to or complementary with the Belle II and Large-Hadron-Collider-beauty experiments,potentially enabling the detection of new physics at energy scales of 10 TeV and above.This potential also extends to the observation of yet-to-be-discovered rare and exotic processes,as well as testing fundamental principles such as lepton flavor universality,lepton and baryon number conservation,etc.,making the CEPC a vibrant platform for flavor physics research.The WW threshold scan,Higgs-factory operation and top-pair productions of the CEPC further enhance its merits in this regard,especially for measuring the Cabibbo-Kobayashi-Maskawa matrix elements,and Flavor-Changing-NeutralCurrent physics of Higgs boson and top quarks.We outline the requirements for detector performance and considerations for future development to achieve the anticipated scientific goals.The role of machine learning for innovative detector design and advanced reconstruction algorithms is also stressed.The CEPC flavor physics program not only develops new capabilities for exploring flavor physics beyond existing projects but also enriches the physics opportunities of this machine.It should be remarked that,given the richness of the CEPC flavor physics,this manuscript is not meant to be a comprehensive survey,but rather an investigation of representative cases.Uncovering the full potential of flavor physics at the CEPC will require further dedicated explorations in the future.
基金Supported by the Major Research Plan of the National Natural Science Foundation of China (No.2010CB834301)the National Natural Science Foundation of China (Nos.10805071 and 10705020)+2 种基金the Chinese Academy of Sciences Key Project of International Co-operation (No.GJHZ09058)the Shanghai Key Project of Basic Research (No.08JC1411900)supported by ICTP TRIL Programme
文摘In line X-ray phase contrast micro-computed tomography （IL-XPCT）, which can be implemented at third generation synchrotron radiation sources or by using a micro-focus X-ray tube, is a powerful technique for non-destructive, high-resolution investigations of a broad variety of materials. At the Shanghai Synchrotron Radiation Facility （SSRF）, the X-ray Imaging and Biomedical Applications Beamline was built and started regular user operation in May 2009. Both qualitative （without phase retrieval） and quantitative （with phase retrieval） three-dimensional IL-XPCT experimental techniques have been established at the beamline IL-XPCT experiments of a test sample （plastic pipes） used to evaluate the technique, and of a biological sample （locust） at the beamline are reported. Two series of images, qualitative and quantitative, including tomographic slices and three-dimensional rendering images were obtained. In qualitative images, there is a strong edge-enhancement which leads to very clear sample contours, while in quantitative images, the edge-enhancement fades but quantitative measurement of sample＇s phase information could be achieved. The experiments demonstrate that the combination of qualitative and quantitative images is useful for biological sample studies.
基金support of the Chinese Academy of Sciences through the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA15020100)support by ASI, under the dedicated eXTP agreements and agreement ASI-INAF (Grant No. 2017-14-H.O.)+3 种基金by INAF and INFN under project REDSOXsupport from the Deutsche Zentrum für Luft- und Raumfahrt, the German Aerospce Center (DLR)support of Science Centre (Grant No. 2013/10/M/ST9/00729)support from MINECO (Grant No. ESP2017-82674-R) and FEDER funds
文摘In this paper we present the enhanced X-ray Timing and Polarimetry mission—eXTP. eXTP is a space science mission designed to study fundamental physics under extreme conditions of density, gravity and magnetism. The mission aims at determining the equation of state of matter at supra-nuclear density, measuring effects of QED, and understanding the dynamics of matter in strong-field gravity. In addition to investigating fundamental physics, eXTP will be a very powerful observatory for astrophysics that will provide observations of unprecedented quality on a variety of galactic and extragalactic objects. In particular, its wide field monitoring capabilities will be highly instrumental to detect the electro-magnetic counterparts of gravitational wave sources.The paper provides a detailed description of:(1) the technological and technical aspects, and the expected performance of the instruments of the scientific payload;(2) the elements and functions of the mission, from the spacecraft to the ground segment.
基金Supported by the National Natural Science Foundation of China (12175248)Supported by the research grant"the Dark Universe:A Synergic Multi-messenger Approach"number (2017X7X85K) under the program PRIN 2017 funded by the Ministero dell’Istruzione,Universitàe della Ricerca (MIUR)
文摘New physics could be explored through loop effects using the precision measurements at the Circular Electron Positron Collider(CEPC)owing to its clean collision environment and high luminosity.In this paper,we focus on two dark matter models that involve additional electroweak fermionic multiplets.We calculate their one-loop corrections in five processes,i.e.,e^(+)e^(-)→μ^(+)μ^(-),Zh,W^(+)W^(-),ZZ,and,Zγ,and investigate the corresponding signatures at the CEPC with the projected sensitivity.We observe that the detectable parameter regions of these processes are complementary.The combined analysis shows that the mass of dark matter m_(χ^(0)_(1))in these two models can be probed up to-150GeV and-450GeV,respectively,at a 95%confidence level.
基金supported by the following funding sources:Science Committee of the Republic of Armenia Grant No.18T-1C180Australian Research Council and research grant Nos.DP180102629,DP170102389,DP170102204,DP150103061,FT130100303,and FT130100018+37 种基金Austrian Federal Ministry of Education,Science and Research,and Austrian Science Fund No.P 31361-N36Natural Sciences and Engineering Research Council of Canada,Compute Canada and CANARIEChinese Academy of Sciences and research grant No.QYZDJ-SSW-SLH011National Natural Science Foundation of China and research grant Nos.11521505,11575017,11675166,11761141009,11705209,and 11975076LiaoNing Revitalization Talents Program under contract No.XLYC1807135Shanghai Municipal Science and Technology Committee under contract No.19ZR1403000Shanghai Pujiang Program under Grant No.18PJ1401000the CAS Center for Excellence in Particle Physics(CCEPP)the Ministry of Education,Youth and Sports of the Czech Republic under Contract No.LTT17020Charles University grants SVV260448 and GAUK 404316European Research Council,7th Framework PIEF-GA-2013-622527Horizon 2020 Marie Sklodowska-Curie grant agreement No.700525’NIOBE,’Horizon 2020 Marie Sklodowska-Curie RISE project JENNIFER grant agreement No.644294Horizon 2020 ERC-Advanced Grant No.267104NewAve No.638528(European grants)L’Institut National de Physique Nucléaire et de Physique des Particules(IN2P3)du CNRS(France),BMBF,DFG,HGF,MPG and AvH Foundation(Germany)Department of Atomic Energy and Department of Science and Technology(India)Israel Science Foundation grant No.2476/17United States-Israel Binational Science Foundation grant No.2016113Istituto Nazionale di Fisica Nucleare and the research grants BELLE2Japan Society for the Promotion of Science,Grant-in-Aid for Scientific Research grant Nos.16H03968,16H03993,16H06492,16K05323,17H01133,17H05405,18K03621,18H03710,18H05226,19H00682,26220706,and 26400255the National Institute of Informatics,and Science Information NETwork 5(SINET5)the Ministry of Education,Culture,Sports,Science,and Technology(MEXT)of JapanNational Research Foundation(NRF)of Korea Grant Nos.2016R1D1A1B01010135,2016R1D1A1B02012900,2018R1A2B3003643,2018R1A6A1A06024970,2018R1D1A1B07047294,2019K1A3A7A09033840,and 2019R1I1A3A01058933Radiation Science Research Institute,Foreign Large-size Research Facility Application Supporting project,the Global Science Experimental Data Hub Center of the Korea Institute of Science and Technology Information and KREONET/GLORIADUniversiti Malaya RU grant,Akademi Sains Malaysia and Ministry of Education MalaysiaFrontiers of Science Program contracts FOINS-296,CB-221329,CB-236394,CB-254409,and CB-180023,and the Thematic Networks program(Mexico)the Polish Ministry of Science and Higher Education and the National Science Centerthe Ministry of Science and Higher Education of the Russian Federation,Agreement14.W03.31.0026Slovenian Research Agency and research grant Nos.J1-9124 and P1-0135Agencia Estatal de Investigacion,Spain grant Nos.FPA2014-55613-P and FPA2017-84445-P,and CIDEGENT/2018/020 of Generalitat ValencianaMinistry of Science and Technology and research grant Nos.MOST106-2112-M-002-005-MY3 and MOST107-2119-M-002-035-MY3,and the Ministry of Education(Taiwan)Thailand Center of Excellence in PhysicsTUBITAK ULAKBIM(Turkey)Ministry of Education and Science of Ukrainethe US National Science Foundation and research grant Nos.PHY-1807007 and PHY-1913789the US Department of Energy and research grant Nos.DE-AC06-76RLO1830,DE-SC0007983,DE-SC0009824,DE-SC0009973,DE-SC0010073,DE-SC0010118,DE-SC0010504,DESC0011784,DE-SC0012704the National Foundation for Science and Technology Development(NAFOSTED)of Vietnam under grant No 103.99-2018.45
文摘From April to July 2018,a data sample at the peak energy of the T(4 S) resonance was collected with the Belle Ⅱ detector at the SuperKEKB electron-positron collider.This is the first data sample of the Belle Ⅱ experiment.Using Bhabha and digamma events,we measure the integrated luminosity of the data sample to be(496.3±0.3±3.0) pb-1,where the first uncertainty is statistical and the second is systematic.This work provides a basis for future luminosity measurements at Belle Ⅱ.
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.
