The thermal widths for heavy quarkonia are calculated for both Coulomb gauge （CG） and Feynman gauge （FG）, and the comparisons between these results with the hard thermal loop （HTL） approximation ones are illustr...The thermal widths for heavy quarkonia are calculated for both Coulomb gauge （CG） and Feynman gauge （FG）, and the comparisons between these results with the hard thermal loop （HTL） approximation ones are illustrated. The dissociation temperatures of heavy quarkonia in thermal medium are also discussed for CG, FG and HTL cases. It is shown that the thermal widths, derived from the HTL approximation and used in many research studies, cause some errors in the practical calculations at the temperature range accessible in the present experiment, and the problem of gauge dependence cannot be avoided when the complete self energy is used in the derivation of potential.展开更多
A calculation of the melting temperatures of heavy quarkonium states with the holographic potential was introduced in a previous work. In this paper, we consider the holographic potential at sub-leading order, which p...A calculation of the melting temperatures of heavy quarkonium states with the holographic potential was introduced in a previous work. In this paper, we consider the holographic potential at sub-leading order, which permits finite coupling corrections to be taken into account. It is found that this correction lowers the dissociation temperatures of heavy quarkonium.展开更多
Within the framework of nonrelativistic-QCD factorization,we calculate both the next-to-leading-order relativistic and QCD corrections to prompt J/ψpair production,with feed-down fromψ(2S)mesons,via photon-photon co...Within the framework of nonrelativistic-QCD factorization,we calculate both the next-to-leading-order relativistic and QCD corrections to prompt J/ψpair production,with feed-down fromψ(2S)mesons,via photon-photon collisions at future e^(+)e^(−)colliders,including the Future Circular Lepton Collider(FCC-ee),the Circular Electron Positron Collider(CEPC),and the Compact Linear Collider(CLIC).We present total cross sections and distributions in single J/ψtransverse momentum and rapidity,as well as in J/ψpair invariant mass.The relativistic and QCD corrections both turn out to be large and negative.However,the production rates are large enough for useful experimental studies.展开更多
Inspired by the recent measurements of the ηc meson production at LHC experiments, we investigate the relativistic correction effect for the fragmentation functions of gluon/charm quark fragmenting into ηc, which co...Inspired by the recent measurements of the ηc meson production at LHC experiments, we investigate the relativistic correction effect for the fragmentation functions of gluon/charm quark fragmenting into ηc, which constitute the crucial nonperturbative element for the ηc production at high pT. Employing three distinct methods,we calculate the next-to-leading-order（NLO） relativistic correction to g →ηc fragmentation function in the NRQCD factorization framework, as well as verifying the existing NLO result for the c →ηc fragmentation function. We also study the evolution behavior of these fragmentation functions with the aid of the DGLAP equation.展开更多
By adopting the adiabatic assumption in the cooling process,we discuss a novel mechanism ofΥ(1S)suppression that occurs due to the fast heating process at the early stage of the fireball,instead of its finite decay w...By adopting the adiabatic assumption in the cooling process,we discuss a novel mechanism ofΥ(1S)suppression that occurs due to the fast heating process at the early stage of the fireball,instead of its finite decay width in a finite temperature medium generated by heavy ion collisions.We calculate the transition probability after the fast heating dissociation as a function of the temperature of the medium and the nuclear modification factor in central collisions and find that the suppression is not negligible at RHIC,even if the width ofΥ(1S)becomes zero.展开更多
In this paper, we investigate the decay of the Higgs boson to J/ψ（γ ） plus a photon based on NRQCD factorization. For the direct process, we calculate the decay width up to QCD NLO. We find that the decay width fo...In this paper, we investigate the decay of the Higgs boson to J/ψ（γ ） plus a photon based on NRQCD factorization. For the direct process, we calculate the decay width up to QCD NLO. We find that the decay width for process H → J/ψ（γ ） ＋γ direct production at the LO is significantly reduced by the NLO QCD corrections. For the indirect process, we calculate the H→γ＊γ, with virtual 7 substantially decaying to J/ψ（γ）, including all the SM Feynman diagrams. The decay width of indirect production is much larger than the direct decay width. Since it is very clean in experiment, the H →J/ψ（ γ） ＋γ decay could be observable at a 14 TeV LHC and it also offers a new way to probe the Yukawa coupling and New Physics at the LHC.展开更多
Applying the AdS/CFT correspondence,the expansion of the heavy-quark potential of N = 4 supersymmetric Yang-Mills theory at large N c is carried out to the next-leading term in the large ’t Hooft coupling at zero tem...Applying the AdS/CFT correspondence,the expansion of the heavy-quark potential of N = 4 supersymmetric Yang-Mills theory at large N c is carried out to the next-leading term in the large ’t Hooft coupling at zero temperature.The strong coupling corresponds to the semi-classical expansion of the stringsigma model,the gravity dual of the Wilson loop operator,with the next-leading term expressed in terms of functional determinants of fluctuations.The singularities of these determinants are examined and their contributions are evaluated numerically.We find the next-leading order correction is negative and suppressed by minus square root of the ’t Hooft coupling relative to the leading order.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
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
By applying the nonrelativistic quantum chromodynamics factorization formalism toγ(1S.2S,3S)hadroproduction,a complete analysis of the polarization parametersλθ,λθФ、andλФfor the production is presented at QCD...By applying the nonrelativistic quantum chromodynamics factorization formalism toγ(1S.2S,3S)hadroproduction,a complete analysis of the polarization parametersλθ,λθФ、andλФfor the production is presented at QCD next-to-leading order.With the long-distance matrix elements extracted from experimental data for the production rate and polarization parameterλθofγhadroproduction,our results provide a good description of the measured parametersλθФandλФin both the helicity and Collins-Soper frames.In our calculations,the frame invariant parameterλ^-is consistent in the two frames.Finally,we mention that there are discrepancies between the available experimental data and corresponding theoretical predictions forλ^-.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 11065010 and 11465021
文摘The thermal widths for heavy quarkonia are calculated for both Coulomb gauge （CG） and Feynman gauge （FG）, and the comparisons between these results with the hard thermal loop （HTL） approximation ones are illustrated. The dissociation temperatures of heavy quarkonia in thermal medium are also discussed for CG, FG and HTL cases. It is shown that the thermal widths, derived from the HTL approximation and used in many research studies, cause some errors in the practical calculations at the temperature range accessible in the present experiment, and the problem of gauge dependence cannot be avoided when the complete self energy is used in the derivation of potential.
基金Supported by QLPL(QLPL201408)and NSFC(11547204,11375070,11135011,11221504)
文摘A calculation of the melting temperatures of heavy quarkonium states with the holographic potential was introduced in a previous work. In this paper, we consider the holographic potential at sub-leading order, which permits finite coupling corrections to be taken into account. It is found that this correction lowers the dissociation temperatures of heavy quarkonium.
基金Supported in part by the German Research Foundation DFG through Research Unit FOR 2926"Next Generation Perturbative QCD for Hadron Structure:Preparing for the Electron-Ion Collider"(409651613)National Natural Science Foundation of China(12061131006)National Natural Science Foundation of China(U1832160,12075177)。
文摘Within the framework of nonrelativistic-QCD factorization,we calculate both the next-to-leading-order relativistic and QCD corrections to prompt J/ψpair production,with feed-down fromψ(2S)mesons,via photon-photon collisions at future e^(+)e^(−)colliders,including the Future Circular Lepton Collider(FCC-ee),the Circular Electron Positron Collider(CEPC),and the Compact Linear Collider(CLIC).We present total cross sections and distributions in single J/ψtransverse momentum and rapidity,as well as in J/ψpair invariant mass.The relativistic and QCD corrections both turn out to be large and negative.However,the production rates are large enough for useful experimental studies.
基金Supported by National Natural Science Foundation of China(11475188,11261130311,11575202,11222549)IHEP Innovation(Y4545170Y2)State Key Lab for Electronics and Particle Detectors
文摘Inspired by the recent measurements of the ηc meson production at LHC experiments, we investigate the relativistic correction effect for the fragmentation functions of gluon/charm quark fragmenting into ηc, which constitute the crucial nonperturbative element for the ηc production at high pT. Employing three distinct methods,we calculate the next-to-leading-order（NLO） relativistic correction to g →ηc fragmentation function in the NRQCD factorization framework, as well as verifying the existing NLO result for the c →ηc fragmentation function. We also study the evolution behavior of these fragmentation functions with the aid of the DGLAP equation.
基金Supported by the NSFC (11547043, 11705125)the “Qinggu” project (1701, 40110) of Tianjin University
文摘By adopting the adiabatic assumption in the cooling process,we discuss a novel mechanism ofΥ(1S)suppression that occurs due to the fast heating process at the early stage of the fireball,instead of its finite decay width in a finite temperature medium generated by heavy ion collisions.We calculate the transition probability after the fast heating dissociation as a function of the temperature of the medium and the nuclear modification factor in central collisions and find that the suppression is not negligible at RHIC,even if the width ofΥ(1S)becomes zero.
基金Supported by National Natural Science Foundation of China(11305001,11105083,11205003)
文摘In this paper, we investigate the decay of the Higgs boson to J/ψ（γ ） plus a photon based on NRQCD factorization. For the direct process, we calculate the decay width up to QCD NLO. We find that the decay width for process H → J/ψ（γ ） ＋γ direct production at the LO is significantly reduced by the NLO QCD corrections. For the indirect process, we calculate the H→γ＊γ, with virtual 7 substantially decaying to J/ψ（γ）, including all the SM Feynman diagrams. The decay width of indirect production is much larger than the direct decay width. Since it is very clean in experiment, the H →J/ψ（ γ） ＋γ decay could be observable at a 14 TeV LHC and it also offers a new way to probe the Yukawa coupling and New Physics at the LHC.
基金Supported by National Natural Science Foundation of China (10975060,10735040)
文摘Applying the AdS/CFT correspondence,the expansion of the heavy-quark potential of N = 4 supersymmetric Yang-Mills theory at large N c is carried out to the next-leading term in the large ’t Hooft coupling at zero temperature.The strong coupling corresponds to the semi-classical expansion of the stringsigma model,the gravity dual of the Wilson loop operator,with the next-leading term expressed in terms of functional determinants of fluctuations.The singularities of these determinants are examined and their contributions are evaluated numerically.We find the next-leading order correction is negative and suppressed by minus square root of the ’t Hooft coupling relative to the leading order.
基金supported by the National Natural Science Foundation of China(12035007,12022512,12147131,12225503,11890710,11890711,and 11935007)Guangdong Major Project of Basic and Applied Basic Research(2020B0301030008)+1 种基金supported by the MOE Key Laboratory of Quark and Lepton Physics(QLPL2021P01)supported by the National Science Foundation of USA(PHY-2209183).
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.
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 in part by the National Natural Science Foundation of China (11905292,11535002, 11675239, 11745006, 11821505, 11947302, 11975242)supported by Key Research Program of Frontier Sciences,CAS,Grant No. QYZDYSSW-SYS006 and Y7292610K1。
文摘By applying the nonrelativistic quantum chromodynamics factorization formalism toγ(1S.2S,3S)hadroproduction,a complete analysis of the polarization parametersλθ,λθФ、andλФfor the production is presented at QCD next-to-leading order.With the long-distance matrix elements extracted from experimental data for the production rate and polarization parameterλθofγhadroproduction,our results provide a good description of the measured parametersλθФandλФin both the helicity and Collins-Soper frames.In our calculations,the frame invariant parameterλ^-is consistent in the two frames.Finally,we mention that there are discrepancies between the available experimental data and corresponding theoretical predictions forλ^-.
