We present a complete study on the J/ψpair hadroproduction at next-to-leading order(NLO)in the nonrelativstic-QCD(NRQCD)framework with the pair of cc¯in either ^(3)S^([1])_(1) or ^(1)S^([8])_(0) fock state.We fo...We present a complete study on the J/ψpair hadroproduction at next-to-leading order(NLO)in the nonrelativstic-QCD(NRQCD)framework with the pair of cc¯in either ^(3)S^([1])_(1) or ^(1)S^([8])_(0) fock state.We found that the contribution of the ^(1)S^([8])_(0) channel at NLO is essential,and for ATLAS,the NRQCD results can describe the experimental data to a certain extent.展开更多
The heavy constituent quark pair of the heavy quarkonium is produced perturbatively and subsequently undergoes hadronization into the bound state non-perturbatively.The production of the heavy quarkonium is essential ...The heavy constituent quark pair of the heavy quarkonium is produced perturbatively and subsequently undergoes hadronization into the bound state non-perturbatively.The production of the heavy quarkonium is essential to testing our understanding of quantum chromodynamics(QCD)in both perturbative and non-perturbative aspects.The electron-positron collider will provide a suitable platform for the precise study of the heavy quarkonium.The higher excited heavy quarkonium may contribute significantly to the ground states,which should be considered for sound estimation.We study the production rates of the higher excited states quarkonium pair in■at the future Z factory under the non-relativistic QCD(NRQCD)framework,where the■represents the color-singlet states■The differential angle distribution of cross sections■is given.We also discuss the uncertainties of cross sections caused by the varying quark masses and the renormalization scaleμ.We show that significant numbers of events for pairs of higher excited state quarkonia can be generated at the super Z factory.展开更多
We perform a complete study of J/ψ pair hadroproduction at next-to-leading order (NLO) in the nonrelativstic-QCD (NRQCD) framework with the cc¯ pair either in the ^(3)S_(1)^([1]) or ^(1)S_(0)^([8]) fock states. ...We perform a complete study of J/ψ pair hadroproduction at next-to-leading order (NLO) in the nonrelativstic-QCD (NRQCD) framework with the cc¯ pair either in the ^(3)S_(1)^([1]) or ^(1)S_(0)^([8]) fock states. It is found that the ^(1)S_(0)^([8]) channel contribution at NLO is essential. Our results indicate that for the CMS, the NRQCD predictions cannot describe the experimental data at all, and the total cross section predicted via NRQCD is smaller than the experimental data by an order of magnitude. Therefore, new mechanisms are needed to understand the CMS data for J/ψ pair production.展开更多
Within the NRQCD factorization framework,we compute the next-to-leading-order QCD corrections to the gluon fragmentation into the ^(1)S_(0)^((1.8)) Fock components of a quarkonium,at the lowest order in velocity expan...Within the NRQCD factorization framework,we compute the next-to-leading-order QCD corrections to the gluon fragmentation into the ^(1)S_(0)^((1.8)) Fock components of a quarkonium,at the lowest order in velocity expan-sion.We follow the operator definition of the fragmentation function advanced by Collins and Soper.The key tech-nique underpinning our calculation is the sector decomposition method widely used in the area of multi-loop compu-tation.It is found that the NLO QCD corrections have significant effects,and qualitatively modify the profiles of the corresponding leading-order fragmentation functions.展开更多
In this paper, we compute the relativistic corrections of the fragmentation functions (FFs) for a heavy quark to Bc and Bc^* within the framework of non-relativistic QCD (NRQCD) factorization. The non-singlet and sing...In this paper, we compute the relativistic corrections of the fragmentation functions (FFs) for a heavy quark to Bc and Bc^* within the framework of non-relativistic QCD (NRQCD) factorization. The non-singlet and singlet DGLAP evolutions are also presented.展开更多
We calculate the next-to-leading order （NLO） quantum chromodynamics （QCD） corrections to double charmonium production processes e^＋e^- → γ＊ →ηc＋hc（1P）/ψ1,2（1D） within the non-relativistic QCD （NRQCD）...We calculate the next-to-leading order （NLO） quantum chromodynamics （QCD） corrections to double charmonium production processes e^＋e^- → γ＊ →ηc＋hc（1P）/ψ1,2（1D） within the non-relativistic QCD （NRQCD） factorization framework. We find that the corrections to ηc＋hc（1P） production are positive, while those to ηc＋ψ1/2（1D） are negative. Unlike the J/ψ＋ηc case, all the corrections here are not large. Uncertainties in the renormalization scale, quark mass and running energy of center-of-mass are discussed, and the scale dependence of these processes is found to be greatly reduced with the NLO QCD corrections.展开更多
We study J/ψ inclusive production in the decays of P-wave bottomonium χbJ（1P,2P） for J=0,1,2. Within the framework of the non-relativistic QCD（NRQCD） factorization method we calculate the contri-butions coming f...We study J/ψ inclusive production in the decays of P-wave bottomonium χbJ（1P,2P） for J=0,1,2. Within the framework of the non-relativistic QCD（NRQCD） factorization method we calculate the contri-butions coming from four relevant processes including one color-singlet process and three color-octet ones,which are b（3PJ,1） → c（3S1,8） ＋ c ＋,b（3S1,8） → c（3S1,1） ＋ g ＋ g,b（3S1,8） → c（3S1,1） ＋ c ＋ and b（3S1,8） → c（3S1,8） ＋g. Our calculation shows that the color-octet processes,especially the gluon fragmen-tation one,contribute the most in the decays of χb0 and χb1. However,the J/ψ production in the χb2 decay is dominated by the color-singlet process. Furthermore,the gluon fragmentation process gives a δ function in the energy fraction distribution of J/ψ,which can be considered to be another characteristic for its identification. From our estimation the branching ratio for these processes is about 10-4-10-5,which indicates that J/ψ inclusive production is detectable at B-factories. Studying these processes would help us to gain a deeper understanding of the color-octet mechanism.展开更多
Based on the nonrelativistic QCD factorization approach, O（αsv2） corrections to J/ψ plus ηc production in e＋e- annihilation at √s= 10.6 GeV are calculated in this work. The numerical results show that the corre...Based on the nonrelativistic QCD factorization approach, O（αsv2） corrections to J/ψ plus ηc production in e＋e- annihilation at √s= 10.6 GeV are calculated in this work. The numerical results show that the correction at αsv2 order is only about a few percent of the total theoretical result. This indicates that the perturbative expansions become convergent and that a higher order correction will be smaller. The uncertainties from the long-distance matrix elements, renormalization scale and the measurement in the experiment are also discussed. Our result is in agreement with the previous result by Jia.展开更多
In this paper, the J/ψ nuclear absorption effect is studied at RHIC and LHC energies with the EKS98 shadowing parameterizations. By assuming that the J/ψ absorption cross section, σ abs , increases with the charmon...In this paper, the J/ψ nuclear absorption effect is studied at RHIC and LHC energies with the EKS98 shadowing parameterizations. By assuming that the J/ψ absorption cross section, σ abs , increases with the charmonium-nucleon （J/ψ-N） center of mass energy, s J/ψN , it is found that σ abs should depend on x F （or y） at a certain center of mass energy per nucleon pair,s , especially at LHC energies. The theoretical results with the x F （or y）-dependence of the absorption effect are in good agreement with the experiment data from PHENIX in d-Au collisions and the predicted results will be examined by the forthcoming experimental data from LHC in d-Pb collisions. Finally, we also present baseline calculations of cold nuclear matter effects on J/ψ production in nucleus-nucleus （A-A） collisions and find that the x F （or y）-dependence of absorption effect is very small at both RHIC and LHC energies in A-A collisions.展开更多
Inclusive γ(1S,2S,3S) photoproduction at the future Circular-Electron-Positron-Collider(CEPC)is studied,using the non-relativistic quantum chromodynamics(NRQCD)factorization formalism.Including the contributions from...Inclusive γ(1S,2S,3S) photoproduction at the future Circular-Electron-Positron-Collider(CEPC)is studied,using the non-relativistic quantum chromodynamics(NRQCD)factorization formalism.Including the contributions from both direct and resolved photons,we present different distributions for the γ(1S,2S,3S) production.Our results suggest that there will be considerable events,implying that well measurements of the T photoproduction can be performed to further study heavy quarkonium physics at electron-positron colliders,in addition to hadron colliders.This supplemental study is very important for clarifying the current situation regarding the heavy quarkonium production mechanism.展开更多
基金Supported by the National Natural Science Foundation of China (NSFC) (1905006)the Fundamental Research Funds for Beijing Universities (X18107)。
文摘We present a complete study on the J/ψpair hadroproduction at next-to-leading order(NLO)in the nonrelativstic-QCD(NRQCD)framework with the pair of cc¯in either ^(3)S^([1])_(1) or ^(1)S^([8])_(0) fock state.We found that the contribution of the ^(1)S^([8])_(0) channel at NLO is essential,and for ATLAS,the NRQCD results can describe the experimental data to a certain extent.
基金Supported by the Scientific Research Fund of Chengdu University of Information Technology(KYTZ2022113)the National Key Research and Development Plan of China,Key Project of Cyberspace Security Governance(2022YFB3103103)。
文摘The heavy constituent quark pair of the heavy quarkonium is produced perturbatively and subsequently undergoes hadronization into the bound state non-perturbatively.The production of the heavy quarkonium is essential to testing our understanding of quantum chromodynamics(QCD)in both perturbative and non-perturbative aspects.The electron-positron collider will provide a suitable platform for the precise study of the heavy quarkonium.The higher excited heavy quarkonium may contribute significantly to the ground states,which should be considered for sound estimation.We study the production rates of the higher excited states quarkonium pair in■at the future Z factory under the non-relativistic QCD(NRQCD)framework,where the■represents the color-singlet states■The differential angle distribution of cross sections■is given.We also discuss the uncertainties of cross sections caused by the varying quark masses and the renormalization scaleμ.We show that significant numbers of events for pairs of higher excited state quarkonia can be generated at the super Z factory.
基金Supported by the National Natural Science Foundation of China(11905006)。
文摘We perform a complete study of J/ψ pair hadroproduction at next-to-leading order (NLO) in the nonrelativstic-QCD (NRQCD) framework with the cc¯ pair either in the ^(3)S_(1)^([1]) or ^(1)S_(0)^([8]) fock states. It is found that the ^(1)S_(0)^([8]) channel contribution at NLO is essential. Our results indicate that for the CMS, the NRQCD predictions cannot describe the experimental data at all, and the total cross section predicted via NRQCD is smaller than the experimental data by an order of magnitude. Therefore, new mechanisms are needed to understand the CMS data for J/ψ pair production.
基金supported by the National Natural Science Foundation of China(12275353 and 11875318).Y.J.is supported in part by the National Natural Science Foundation of China(11475188)CRC110 by DGF and NSFC(11621131001)。
文摘Within the NRQCD factorization framework,we compute the next-to-leading-order QCD corrections to the gluon fragmentation into the ^(1)S_(0)^((1.8)) Fock components of a quarkonium,at the lowest order in velocity expan-sion.We follow the operator definition of the fragmentation function advanced by Collins and Soper.The key tech-nique underpinning our calculation is the sector decomposition method widely used in the area of multi-loop compu-tation.It is found that the NLO QCD corrections have significant effects,and qualitatively modify the profiles of the corresponding leading-order fragmentation functions.
基金Supported in part by the National Natural Science Foundation of China(11275263 and 11635009)
文摘In this paper, we compute the relativistic corrections of the fragmentation functions (FFs) for a heavy quark to Bc and Bc^* within the framework of non-relativistic QCD (NRQCD) factorization. The non-singlet and singlet DGLAP evolutions are also presented.
基金Supported by Ministry of Science and Technology of the People’s Republic of China(2015CB856703)National Natural Science Foundation of China(11175249,11375200)
文摘We calculate the next-to-leading order （NLO） quantum chromodynamics （QCD） corrections to double charmonium production processes e^＋e^- → γ＊ →ηc＋hc（1P）/ψ1,2（1D） within the non-relativistic QCD （NRQCD） factorization framework. We find that the corrections to ηc＋hc（1P） production are positive, while those to ηc＋ψ1/2（1D） are negative. Unlike the J/ψ＋ηc case, all the corrections here are not large. Uncertainties in the renormalization scale, quark mass and running energy of center-of-mass are discussed, and the scale dependence of these processes is found to be greatly reduced with the NLO QCD corrections.
文摘We study J/ψ inclusive production in the decays of P-wave bottomonium χbJ（1P,2P） for J=0,1,2. Within the framework of the non-relativistic QCD（NRQCD） factorization method we calculate the contri-butions coming from four relevant processes including one color-singlet process and three color-octet ones,which are b（3PJ,1） → c（3S1,8） ＋ c ＋,b（3S1,8） → c（3S1,1） ＋ g ＋ g,b（3S1,8） → c（3S1,1） ＋ c ＋ and b（3S1,8） → c（3S1,8） ＋g. Our calculation shows that the color-octet processes,especially the gluon fragmen-tation one,contribute the most in the decays of χb0 and χb1. However,the J/ψ production in the χb2 decay is dominated by the color-singlet process. Furthermore,the gluon fragmentation process gives a δ function in the energy fraction distribution of J/ψ,which can be considered to be another characteristic for its identification. From our estimation the branching ratio for these processes is about 10-4-10-5,which indicates that J/ψ inclusive production is detectable at B-factories. Studying these processes would help us to gain a deeper understanding of the color-octet mechanism.
基金Supported by National Natural Science Foundation of China(10979056,10935012)
文摘Based on the nonrelativistic QCD factorization approach, O（αsv2） corrections to J/ψ plus ηc production in e＋e- annihilation at √s= 10.6 GeV are calculated in this work. The numerical results show that the correction at αsv2 order is only about a few percent of the total theoretical result. This indicates that the perturbative expansions become convergent and that a higher order correction will be smaller. The uncertainties from the long-distance matrix elements, renormalization scale and the measurement in the experiment are also discussed. Our result is in agreement with the previous result by Jia.
基金Supported by Natural Science Foundation of Hebei Province (A2008000421)
文摘In this paper, the J/ψ nuclear absorption effect is studied at RHIC and LHC energies with the EKS98 shadowing parameterizations. By assuming that the J/ψ absorption cross section, σ abs , increases with the charmonium-nucleon （J/ψ-N） center of mass energy, s J/ψN , it is found that σ abs should depend on x F （or y） at a certain center of mass energy per nucleon pair,s , especially at LHC energies. The theoretical results with the x F （or y）-dependence of the absorption effect are in good agreement with the experiment data from PHENIX in d-Au collisions and the predicted results will be examined by the forthcoming experimental data from LHC in d-Pb collisions. Finally, we also present baseline calculations of cold nuclear matter effects on J/ψ production in nucleus-nucleus （A-A） collisions and find that the x F （or y）-dependence of absorption effect is very small at both RHIC and LHC energies in A-A collisions.
基金Supported by the National Natural Science Foundation of China(11975242)and the Key Research Program of Frontier Sciences,CAS,(Y7292610K1)。
文摘Inclusive γ(1S,2S,3S) photoproduction at the future Circular-Electron-Positron-Collider(CEPC)is studied,using the non-relativistic quantum chromodynamics(NRQCD)factorization formalism.Including the contributions from both direct and resolved photons,we present different distributions for the γ(1S,2S,3S) production.Our results suggest that there will be considerable events,implying that well measurements of the T photoproduction can be performed to further study heavy quarkonium physics at electron-positron colliders,in addition to hadron colliders.This supplemental study is very important for clarifying the current situation regarding the heavy quarkonium production mechanism.
