J/ψ suppression in p-A collisions is studied by considering the nuclear effects on parton distribution,energy loss of beam proton and the finial state energy loss of color octet cc. The leading-order computations for...J/ψ suppression in p-A collisions is studied by considering the nuclear effects on parton distribution,energy loss of beam proton and the finial state energy loss of color octet cc. The leading-order computations for J/ψproduction cross-section ratios RW/Be（x F） are presented and compared with the selected E866 experimental data with the cc remaining colored on its entire path in the medium. It is shown that the combination of the different nuclear effects accounts quite well for the observed J/ψ suppression in the experimental data. It is found that the J/ψ suppression on RW/Be（x F） from the initial state nuclear effects is more important than that induced by the energy loss of color octet cc in the large x F region. Whether the cc pair energy loss is linear or quadratic with the path length is not determined. The obtained cc pair energy loss per unit path length α = 2.78±0.81 Ge V/fm, which indicates that the heavy quark in cold nuclear matter can lose more energy compared to the outgoing light quark.展开更多
Considering the volatility of the propagation path for charmonium passing across the nuclear target in J/ψ formation from p-A collisions, the charmonium energy loss is investigated using Salgado-Wiedemann quenching w...Considering the volatility of the propagation path for charmonium passing across the nuclear target in J/ψ formation from p-A collisions, the charmonium energy loss is investigated using Salgado-Wiedemann quenching weights. A successful description regarding J/ψsuppression of R_(w(Fe)/Be)(x_F) from the E866 experiment for 0.2 <x_F<0.65 gives the transport coefficient q = 0.29 ± 0.07 GeV^2/fm for the colored cc energy loss.The calculated result indicates that radiative energy loss of a parton should be independent of its mass at high energy.The calculations are further compared to LHC and RHIC measurements.展开更多
We study charmed baryon resonances that are generated dynamically from a coupled-channel unitary approach that implements heavy-quark symmetry. Some states can already be identified with experimental observations, suc...We study charmed baryon resonances that are generated dynamically from a coupled-channel unitary approach that implements heavy-quark symmetry. Some states can already be identified with experimental observations, such as Ac（2595）, Ac（2660）, Ec（2902） or Ac（2941）, while others need a compilation of more experimental data as well as an extension of the model to include higher order contributions. We also compare our model to previous SU（4） schemes.展开更多
We report here the mass spectrum and magnetic moments of ccq（q ∈ u,d,s） systems in the potential model framework by assuming the inter-quark potential as the colour coulomb plus power form with power index ν varyi...We report here the mass spectrum and magnetic moments of ccq（q ∈ u,d,s） systems in the potential model framework by assuming the inter-quark potential as the colour coulomb plus power form with power index ν varying between 0.1 to 2.0.Here the two charm quarks are considered for the diquark states.The conventional one gluon exchange interaction has been employed to get the hyperfine and the fine structure between different states.We have predicted many low-lying states whose experimental verification can exclusively support the quark-diquark structure of the baryons.展开更多
Understanding the EMC effect and its relation to the short-range nucleon-nucleon correlations(SRC)in nuclei is a major challenge for modem nuclear physics.One of the key aspects of the connection between these phenome...Understanding the EMC effect and its relation to the short-range nucleon-nucleon correlations(SRC)in nuclei is a major challenge for modem nuclear physics.One of the key aspects of the connection between these phenomena is the universality.The universality states that the SRC is responsible for the EMC effect and that the modification of the partonic structure of the SRC is the same in different nuclei.The flavor dependence of the universal-ity is one of the unanswered questions.The investigations conducted to date have demonstrated the existence and universality of the SRC for light u and d quarks.Recently,it was suggested that the universality for heavy flavors can be studied through their deep subthreshold production in yA and eA collisions.In this paper,we discuss an alternative possibility to access the strange and gluon high-A"structure of the SRC and to establish universality for heavy flavors using nuclear semi-inclusive deep inelastic scattering(nSIDIS),which probes different quark flavor combinations depending on the final state hadron.The specific reaction can be"tagged"by observation of a strange or charmed particle registered in coincidence with the scattering lepton.The universality of the SRC can be tested in the kinematic region,i.e.,X>1,where the contribution to the cross section from SRC becomes dominant.Exploring the strangeness,charmonium,and open charm will shed light on the role of quarks and gluons in nuclei,thereby developing an understanding of how nuclei emerge within QCD.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
A search for the doubly charmed baryon ?cc+ with the decay mode c Ω_(cc)^(+)→ Ξc+K-π+ is performed using proton-proton collision data at a centre-of-mass energy of 13 TeV collected by the LHCb experiment from 2016...A search for the doubly charmed baryon ?cc+ with the decay mode c Ω_(cc)^(+)→ Ξc+K-π+ is performed using proton-proton collision data at a centre-of-mass energy of 13 TeV collected by the LHCb experiment from 2016 to 2018, corresponding to an integrated luminosity of 5.4 fb-1. No significant signal is observed within the invariant mass range of 3.6 to 4.0 GeV/c2. Upper limits are set on the ratio R of the production cross-section times the total branching fraction of the Ω_(cc)^(+)→ Ξc+K-π+ decay with respect to the Ξcc++→ Λc+K-π+π+ decay. Upper limits at 95% credibility level for R in the range 0.005 to 0.11 are obtained for diferent hypotheses on the ?cc+ mass and lifetime in the rapidity range from 2.0 to 4.5 and transverse momentum range from 4 to 15 GeV/c.展开更多
The yields of the charmed mesons in e^+e^- annihilations have been calculated in virtue of the quark production rule and quark combination rule proposed in Ref. [1]. The results are in agreement with the experimental ...The yields of the charmed mesons in e^+e^- annihilations have been calculated in virtue of the quark production rule and quark combination rule proposed in Ref. [1]. The results are in agreement with the experimental data, which shows that the mechanism for e^+e^- annihilation into hardons is successful.展开更多
Apart from the charmful decay channels of Y（4260）, the charmless decay channels of Y（4260） also provide us a good platform to study the nature and the decay mechanism of Y（4260）. In this paper, we propose to pro...Apart from the charmful decay channels of Y（4260）, the charmless decay channels of Y（4260） also provide us a good platform to study the nature and the decay mechanism of Y（4260）. In this paper, we propose to probe the structure of Y（4260） through the charmless decays Y（4260）→VP via intermediate D1D＋c.c. meson loops, where V and P stand for light vector and pseudoscalar mesons, respectively. Under the molecule ansatz of Y（4260）, the predicted total branching ratio BRVP for all Y（4260） → VP processes are about（0.34＋0.32-0.23）% to（0.75＋0.72-0.52）% with the cutoff parameter α=2–3. Numerical results show that the intermediate D1D＋c.c. meson loops may be a possible transition mechanism in the Y（4260） → VP decays. These predicted branching ratios are the same order to that of Y（4260）→Z＋c（3900）π-, which may be an evidence of D1 D molecule and can be examined by the forthcoming BESdata in the near future.展开更多
Having a precise knowledge of the charm quark component can lead to a better understanding of the fundamental structure of the nucleon. Furthermore, the charm quark distribution function plays an important role in the...Having a precise knowledge of the charm quark component can lead to a better understanding of the fundamental structure of the nucleon. Furthermore, the charm quark distribution function plays an important role in the study of many processes which are sensitive to the charm quark content of the nucleon. In the standard global analysis of patton distribution functions （PDFs）, the charm quark distribution arises perturbatively through the splitting of the gluon into charm-anticharm pairs in the DGLAP evolution equations. Nevertheless, the existence of nonperturbative intrinsic charm quarks in the proton has also been predicted by QCD. In this paper, we study some phenomenological models within the light-cone framework to predict the nonperturbative intrinsic charm quark content of the nucleon. We investigate the impact of these models on the prediction ofγ-＋ c-jet production in pp collisions at the LHC and compare our results on pp→γ, ＋ c-jet with the experimental data of DO.展开更多
Using the covariant light-front approach with conventional vertex functions, we estimate the production rates of D-wave charmed/charmed-strange mesons via the B_((s)) semileptonic decays. As the calculated production ...Using the covariant light-front approach with conventional vertex functions, we estimate the production rates of D-wave charmed/charmed-strange mesons via the B_((s)) semileptonic decays. As the calculated production rates are significant, it seems possible to experimentally search for D-wave charmed/charmed-strange mesons via semileptonic decays, which may provide an additional approach for exploring D-wave charmed/charmed-strange mesons.展开更多
The energy loss effect of incoming gluons from J/ψ production in p-A（or d-A） collisions is investigated by means of the E866, RHIC and LHC experimental data. The gluon mean energy loss per unit path length d E/d L ...The energy loss effect of incoming gluons from J/ψ production in p-A（or d-A） collisions is investigated by means of the E866, RHIC and LHC experimental data. The gluon mean energy loss per unit path length d E/d L = 2.18 ± 0.14 Ge V/fm is extracted by fitting the E866 experimental data for J/ψ production cross section ratios R W（Fe）/Be（x F）. The obtained result indicates that the incoming gluons lose more energy than the incident quarks. By comparing the theoretical results with E866, RHIC, and LHC experimental data, it is found that the nuclear suppression due to the incident gluon（quark） energy loss reduces（increases） with the increase of the kinematic variable x F（or y）. The energy loss effect of incoming gluons plays an important role in the suppression of J/ψ production in a wide energy range from√s = 38.7 Ge V to√s = 5.0 Te V, and the influence of incident quark energy loss can be ignored for high energies（such as at RHIC and LHC energy）.展开更多
基金Supported by National Natural Science Foundation of China(11075044,11347107)Natural Science Foundation of Hebei Province(A2013209299)
文摘J/ψ suppression in p-A collisions is studied by considering the nuclear effects on parton distribution,energy loss of beam proton and the finial state energy loss of color octet cc. The leading-order computations for J/ψproduction cross-section ratios RW/Be（x F） are presented and compared with the selected E866 experimental data with the cc remaining colored on its entire path in the medium. It is shown that the combination of the different nuclear effects accounts quite well for the observed J/ψ suppression in the experimental data. It is found that the J/ψ suppression on RW/Be（x F） from the initial state nuclear effects is more important than that induced by the energy loss of color octet cc in the large x F region. Whether the cc pair energy loss is linear or quadratic with the path length is not determined. The obtained cc pair energy loss per unit path length α = 2.78±0.81 Ge V/fm, which indicates that the heavy quark in cold nuclear matter can lose more energy compared to the outgoing light quark.
基金supported in part by the National Natural Science Foundation of China(No.11405043)the Natural Science Foundation of Hebei Province(No.A2018209269)
文摘Considering the volatility of the propagation path for charmonium passing across the nuclear target in J/ψ formation from p-A collisions, the charmonium energy loss is investigated using Salgado-Wiedemann quenching weights. A successful description regarding J/ψsuppression of R_(w(Fe)/Be)(x_F) from the E866 experiment for 0.2 <x_F<0.65 gives the transport coefficient q = 0.29 ± 0.07 GeV^2/fm for the colored cc energy loss.The calculated result indicates that radiative energy loss of a parton should be independent of its mass at high energy.The calculations are further compared to LHC and RHIC measurements.
基金Supported by EU contract FLAVIAnet MRTN-CT-2006-035482, by the contract FIS2008-01143 from MEC (Spain) and FEDERby the Generalitat de Catalunya contract 2005SGR-00343, and the Junta de Andalucía grants FQM225, FQM481 and P06-FQM-01735This research is part of the EU Integrated Infrastructure Initiative Hadron Physics Project under contractnumber RII3-CT-2004-506078
文摘We study charmed baryon resonances that are generated dynamically from a coupled-channel unitary approach that implements heavy-quark symmetry. Some states can already be identified with experimental observations, such as Ac（2595）, Ac（2660）, Ec（2902） or Ac（2941）, while others need a compilation of more experimental data as well as an extension of the model to include higher order contributions. We also compare our model to previous SU（4） schemes.
基金the financial support from University Grant Commission,Government of India,under a Major Research Project F.32-31/2006(SR)
文摘We report here the mass spectrum and magnetic moments of ccq（q ∈ u,d,s） systems in the potential model framework by assuming the inter-quark potential as the colour coulomb plus power form with power index ν varying between 0.1 to 2.0.Here the two charm quarks are considered for the diquark states.The conventional one gluon exchange interaction has been employed to get the hyperfine and the fine structure between different states.We have predicted many low-lying states whose experimental verification can exclusively support the quark-diquark structure of the baryons.
文摘Understanding the EMC effect and its relation to the short-range nucleon-nucleon correlations(SRC)in nuclei is a major challenge for modem nuclear physics.One of the key aspects of the connection between these phenomena is the universality.The universality states that the SRC is responsible for the EMC effect and that the modification of the partonic structure of the SRC is the same in different nuclei.The flavor dependence of the universal-ity is one of the unanswered questions.The investigations conducted to date have demonstrated the existence and universality of the SRC for light u and d quarks.Recently,it was suggested that the universality for heavy flavors can be studied through their deep subthreshold production in yA and eA collisions.In this paper,we discuss an alternative possibility to access the strange and gluon high-A"structure of the SRC and to establish universality for heavy flavors using nuclear semi-inclusive deep inelastic scattering(nSIDIS),which probes different quark flavor combinations depending on the final state hadron.The specific reaction can be"tagged"by observation of a strange or charmed particle registered in coincidence with the scattering lepton.The universality of the SRC can be tested in the kinematic region,i.e.,X>1,where the contribution to the cross section from SRC becomes dominant.Exploring the strangeness,charmonium,and open charm will shed light on the role of quarks and gluons in nuclei,thereby developing an understanding of how nuclei emerge within QCD.
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Open Access funding provided by CERN(European Organization for Nuclear Research).
文摘A search for the doubly charmed baryon ?cc+ with the decay mode c Ω_(cc)^(+)→ Ξc+K-π+ is performed using proton-proton collision data at a centre-of-mass energy of 13 TeV collected by the LHCb experiment from 2016 to 2018, corresponding to an integrated luminosity of 5.4 fb-1. No significant signal is observed within the invariant mass range of 3.6 to 4.0 GeV/c2. Upper limits are set on the ratio R of the production cross-section times the total branching fraction of the Ω_(cc)^(+)→ Ξc+K-π+ decay with respect to the Ξcc++→ Λc+K-π+π+ decay. Upper limits at 95% credibility level for R in the range 0.005 to 0.11 are obtained for diferent hypotheses on the ?cc+ mass and lifetime in the rapidity range from 2.0 to 4.5 and transverse momentum range from 4 to 15 GeV/c.
文摘The yields of the charmed mesons in e^+e^- annihilations have been calculated in virtue of the quark production rule and quark combination rule proposed in Ref. [1]. The results are in agreement with the experimental data, which shows that the mechanism for e^+e^- annihilation into hardons is successful.
基金Supported by National Natural Science Foundation of China(11275113,11205164)
文摘Apart from the charmful decay channels of Y（4260）, the charmless decay channels of Y（4260） also provide us a good platform to study the nature and the decay mechanism of Y（4260）. In this paper, we propose to probe the structure of Y（4260） through the charmless decays Y（4260）→VP via intermediate D1D＋c.c. meson loops, where V and P stand for light vector and pseudoscalar mesons, respectively. Under the molecule ansatz of Y（4260）, the predicted total branching ratio BRVP for all Y（4260） → VP processes are about（0.34＋0.32-0.23）% to（0.75＋0.72-0.52）% with the cutoff parameter α=2–3. Numerical results show that the intermediate D1D＋c.c. meson loops may be a possible transition mechanism in the Y（4260） → VP decays. These predicted branching ratios are the same order to that of Y（4260）→Z＋c（3900）π-, which may be an evidence of D1 D molecule and can be examined by the forthcoming BESdata in the near future.
文摘Having a precise knowledge of the charm quark component can lead to a better understanding of the fundamental structure of the nucleon. Furthermore, the charm quark distribution function plays an important role in the study of many processes which are sensitive to the charm quark content of the nucleon. In the standard global analysis of patton distribution functions （PDFs）, the charm quark distribution arises perturbatively through the splitting of the gluon into charm-anticharm pairs in the DGLAP evolution equations. Nevertheless, the existence of nonperturbative intrinsic charm quarks in the proton has also been predicted by QCD. In this paper, we study some phenomenological models within the light-cone framework to predict the nonperturbative intrinsic charm quark content of the nucleon. We investigate the impact of these models on the prediction ofγ-＋ c-jet production in pp collisions at the LHC and compare our results on pp→γ, ＋ c-jet with the experimental data of DO.
基金Supported by the National Natural Science Foundation of China(11222547,11175073,11647301)the National Program for Support of Top-notch Young Professionalsthe Fundamental Research Funds for the Central Universities
文摘Using the covariant light-front approach with conventional vertex functions, we estimate the production rates of D-wave charmed/charmed-strange mesons via the B_((s)) semileptonic decays. As the calculated production rates are significant, it seems possible to experimentally search for D-wave charmed/charmed-strange mesons via semileptonic decays, which may provide an additional approach for exploring D-wave charmed/charmed-strange mesons.
基金Supported by National Natural Science Foundation of China(11405043,11575052)
文摘The energy loss effect of incoming gluons from J/ψ production in p-A（or d-A） collisions is investigated by means of the E866, RHIC and LHC experimental data. The gluon mean energy loss per unit path length d E/d L = 2.18 ± 0.14 Ge V/fm is extracted by fitting the E866 experimental data for J/ψ production cross section ratios R W（Fe）/Be（x F）. The obtained result indicates that the incoming gluons lose more energy than the incident quarks. By comparing the theoretical results with E866, RHIC, and LHC experimental data, it is found that the nuclear suppression due to the incident gluon（quark） energy loss reduces（increases） with the increase of the kinematic variable x F（or y）. The energy loss effect of incoming gluons plays an important role in the suppression of J/ψ production in a wide energy range from√s = 38.7 Ge V to√s = 5.0 Te V, and the influence of incident quark energy loss can be ignored for high energies（such as at RHIC and LHC energy）.
