The new members of the charm-strange family Dsj^＊（2317）, Dsj（2460）, and Ds（2632）, which have the surprising properties, are challenging the present models. Many theoretical interpretations have been devoted to ...The new members of the charm-strange family Dsj^＊（2317）, Dsj（2460）, and Ds（2632）, which have the surprising properties, are challenging the present models. Many theoretical interpretations have been devoted to this issue. Most authors suggest that they are not the conventional cs^- quark model states, but possibly are four-quark states, molecule states, or mixtures of a P-wave cs^- and a four-quark state. In this work, we follow the four-quark-state picture, and study the masses of cnn^-s^-/css^-s^- states （n is u or d quark） in the chiral SU（3） quark model. The numerical results show that the mass of the mixed four-quark state （cnn^-s^-/css^-s^-） with spin parity j^P ： 0^＋ might not be Ds （2632）. At the same time, we also conclude that Dsj^＊（2317） and Dsj（2460） cannot be explained as the pure four-quark state.展开更多
By differentiating the dressed quark propagator with respect to a variable background field, the linear response of the dressed quark propagator in the presence of the background field can be obtained. From this gener...By differentiating the dressed quark propagator with respect to a variable background field, the linear response of the dressed quark propagator in the presence of the background field can be obtained. From this general method, using the vector background tield as an illustration, we extract a general formula for the four-quark condensate （0： q（0）γμq（0）q（0）γμq（0） ： ｜0）. This formula contains the corresponding fully dressed vector vertex. We use this formula to analyze the factorization problem of the four-quark condensate and show that in the bare vertex approximation factorization holds exactly.展开更多
Hadrons made by diquark-antidiquark pairs(tetraquarks)are held together by QCD forces in an overall color singlet.As stated in the original proposals and similarly to baryons and qq mesons,tetraquarks form complete mu...Hadrons made by diquark-antidiquark pairs(tetraquarks)are held together by QCD forces in an overall color singlet.As stated in the original proposals and similarly to baryons and qq mesons,tetraquarks form complete multiplets of the flavour symmetry,SU(3)f.展开更多
Recently,the LHCb Collaboration reported the doubly charmed state T^(+)with IJ^(P)=01^(+)in the D^(0)^(0)π^(+) invariant mass spectrum[1].Its extremely small binding energy and width can match very well with the pred...Recently,the LHCb Collaboration reported the doubly charmed state T^(+)with IJ^(P)=01^(+)in the D^(0)^(0)π^(+) invariant mass spectrum[1].Its extremely small binding energy and width can match very well with the prediction of the DD*molecular state[2,3].展开更多
We study strong decays of the possible fully-charm tetraquarks recently observed by LHCb,and calculate their relative branching ratios through the Fierz rearrangement.Together with our previous QCD sum rule study,our ...We study strong decays of the possible fully-charm tetraquarks recently observed by LHCb,and calculate their relative branching ratios through the Fierz rearrangement.Together with our previous QCD sum rule study,our results suggest that the broad structure around 6.2–6.8 GeV can be interpreted as an S-wave cccc tetraquark state with JPC=0++or 2++,and the narrow structure around 6.9 GeV can be interpreted as a P-wave one with JPC=0-+or 1-+.These structures were observed in the di-J=w invariant mass spectrum,and we propose to confirm them in the di-gc;J/ψhc;ηcχc0,and ηcχc1channels.We also propose to search for their partner states having the negative charge-conjugation parity in the J/ψηc;J/ψχc0;J/ψχc1,and ηchc channels.展开更多
基金National Natural Science Foundation of China under Grant No 10475087
文摘The new members of the charm-strange family Dsj^＊（2317）, Dsj（2460）, and Ds（2632）, which have the surprising properties, are challenging the present models. Many theoretical interpretations have been devoted to this issue. Most authors suggest that they are not the conventional cs^- quark model states, but possibly are four-quark states, molecule states, or mixtures of a P-wave cs^- and a four-quark state. In this work, we follow the four-quark-state picture, and study the masses of cnn^-s^-/css^-s^- states （n is u or d quark） in the chiral SU（3） quark model. The numerical results show that the mass of the mixed four-quark state （cnn^-s^-/css^-s^-） with spin parity j^P ： 0^＋ might not be Ds （2632）. At the same time, we also conclude that Dsj^＊（2317） and Dsj（2460） cannot be explained as the pure four-quark state.
基金The project supported in part by National Natural Science Foundation of China under Grant Nos. 10175033, 10135030, and 10575050 and the Research Fund for the Doctoral Program of Higher Education under Grant No. 20030284009
文摘By differentiating the dressed quark propagator with respect to a variable background field, the linear response of the dressed quark propagator in the presence of the background field can be obtained. From this general method, using the vector background tield as an illustration, we extract a general formula for the four-quark condensate （0： q（0）γμq（0）q（0）γμq（0） ： ｜0）. This formula contains the corresponding fully dressed vector vertex. We use this formula to analyze the factorization problem of the four-quark condensate and show that in the bare vertex approximation factorization holds exactly.
文摘Hadrons made by diquark-antidiquark pairs(tetraquarks)are held together by QCD forces in an overall color singlet.As stated in the original proposals and similarly to baryons and qq mesons,tetraquarks form complete multiplets of the flavour symmetry,SU(3)f.
基金partly supported by the National Natural Science Foundation of China(11975033 and 12070131001)Chongqing Natural Science Foundation(cstc2019jcyj-msxm X0409)Fundamental Research Funds for the Central Universities(SWU118111)。
文摘Recently,the LHCb Collaboration reported the doubly charmed state T^(+)with IJ^(P)=01^(+)in the D^(0)^(0)π^(+) invariant mass spectrum[1].Its extremely small binding energy and width can match very well with the prediction of the DD*molecular state[2,3].
基金supported by the National Natural Science Foundation of China (11722540 and 11975033)the Chinese National Youth Thousand Talents Program+2 种基金the China National Funds for Distinguished Young Scientists (11825503)the National Program for Support of Top-notch Young Professionalsthe Fundamental Research Funds for the Central Universities。
文摘We study strong decays of the possible fully-charm tetraquarks recently observed by LHCb,and calculate their relative branching ratios through the Fierz rearrangement.Together with our previous QCD sum rule study,our results suggest that the broad structure around 6.2–6.8 GeV can be interpreted as an S-wave cccc tetraquark state with JPC=0++or 2++,and the narrow structure around 6.9 GeV can be interpreted as a P-wave one with JPC=0-+or 1-+.These structures were observed in the di-J=w invariant mass spectrum,and we propose to confirm them in the di-gc;J/ψhc;ηcχc0,and ηcχc1channels.We also propose to search for their partner states having the negative charge-conjugation parity in the J/ψηc;J/ψχc0;J/ψχc1,and ηchc channels.
