Electron-positron colliders operating in the GeV center-of-mass range,or tau-charm energy region,have been proved to enable competitive frontier research due to several unique features.With the progress of high-energy...Electron-positron colliders operating in the GeV center-of-mass range,or tau-charm energy region,have been proved to enable competitive frontier research due to several unique features.With the progress of high-energy physics in the last two decades,a new-generation Tau-Charm factory,called the Super Tau-Charm Facility(STCF),has been actively promoted by the particle physics community in China.STCF has the potential to address fundamental questions such as the essence of color confinement and the matter-antimatter asymmetry within the next decades.The main design goals of the STCF are a center-of-mass energy ranging from 2 to 7 GeV and a luminosity surpassing 5×10^(34)cm^(−2)s^(−1)that is optimized at a center-of-mass energy of 4 GeV,which is approximately 50 times that of the currently operating Tau-Charm factory-BEPCII.The STCF accelerator has two main parts:a double-ring collider with a crab-waist collision scheme and an injector that provides top-up injections for both electron and positron beams.As a typical third-generation electron-positron circular collider,the STCF accelerator faces many challenges in both accelerator physics and technology.In this paper,the conceptual design of the STCF accelerator complex is presented,including the ongoing efforts and plans for technological research and develop-ment,as well as the required infrastructure.The STCF project aims to secure support from the Chinese central government for its construction during the 15th Five-Year Plan(2026-2030).展开更多
We predict a new physical phenomenon,induced fission-like process and chain reaction of hadronic molecular states.As a molecular state,if induced by a D meson,the X(3872)can split into D■final state which is forbidde...We predict a new physical phenomenon,induced fission-like process and chain reaction of hadronic molecular states.As a molecular state,if induced by a D meson,the X(3872)can split into D■final state which is forbidden due to the spin-parity conservation.The breeding of the D meson of the reaction,such as D^(0)X(3872)→D^(0)■0D^(0),makes the chain reaction of X(3872)matter possible.We estimate the cross section of the D meson induced fission-like process of X(3872)into two D mesons.With very small D^(0) beam momentum of 1 e V,the total cross section reaches an order of 1000 b,and decreases rapidly with the increasing beam momentum.With the transition of D^(*)meson in molecular states to a D meson,the X(3872)can release large energy,which is acquired by the final mesons.The momentum distributions of the final D mesons are analyzed.In the laboratory frame,the spectator D meson in molecular state concentrates in the low momentum area.The energy from the transition from D^(*)to D meson is mainly acquired by two scattered D mesons.The results suggest that the D meson environment will lead to the induced fission-like process and chain reaction of the X(3827).Such a phenomenon can be extended to other hadronic molecular states.展开更多
Inspired by the P_(cs)(4459)reported by the LHCb collaboration recently,we investigate the P_(cs)(4459)production from Ξ_(b) decay in a molecular scenario using an effective Lagrangian approach.With different JP assi...Inspired by the P_(cs)(4459)reported by the LHCb collaboration recently,we investigate the P_(cs)(4459)production from Ξ_(b) decay in a molecular scenario using an effective Lagrangian approach.With different JP assignments to P_(cs)(4459),the magnitude of branching fractions of Ξ_(b)→P_(cs)(4459)K is estimated,which is of the order of 10−4.Together with the decay properties of P_(cs)(4459),the present estimations could be further testified by precise measurements and contribute to a better understanding of the molecular interpretations and the exploration of JP quantum numbers of P_(cs)(4459).展开更多
We adopt the quark pair creation model to investigate the light meson emissions of several charmoniumlike states.The quark pair creation model is applied to four-body systems,and we calculate the pion/kaon emissions o...We adopt the quark pair creation model to investigate the light meson emissions of several charmoniumlike states.The quark pair creation model is applied to four-body systems,and we calculate the pion/kaon emissions of X(4700),Z_(c)(4430),Y(4230),Y(4360),Y(4390),and Y(4660)within compact tetraquark configurations.We find that the pion/kaon decay widths of X(4700)and Z_(c)(4430)the resonances Y(4230),Y(4360),Y(4390),and Y(4660)cay behaviors will provide useful information for future experimental searches and theoretical interpretations.展开更多
In this paper,we propose to investigate the d_(NΩ)dibaryon production in the K-p-→d_(NΩ)≡0 process by utilizing a kaon beam with a typical momentum of approximately 10 GeV,which may be available at COMPASS,OKA@U-7...In this paper,we propose to investigate the d_(NΩ)dibaryon production in the K-p-→d_(NΩ)≡0 process by utilizing a kaon beam with a typical momentum of approximately 10 GeV,which may be available at COMPASS,OKA@U-70,and SPS@CERN.The cross sections for K-p-→d_(NΩ)=O are estimated,and in particular,the magnitude of the cross sections is evaluated to be several hundred nanobarns at Pk=20 GeV.Considering that the d_(NΩ)dibaryon dominantly decays into≡Λand≡∑,we also estimate the cross sections for K-p→≡0Λ≡0 and K~p→≡-∑+≡0,where the d_(NΩ)dibaryon can be observed in the invariant mass distributions of≡0Λand≡-∑+,respectively.展开更多
Motivated by the large branching fractions of J/ψ→f0(1710)ω/f0(1710)ϕand the light exotic candidates,we found that there may exist molecular states composed of f0(1710)ωand f0(1710)ϕ,which correspond to X(2440)and...Motivated by the large branching fractions of J/ψ→f0(1710)ω/f0(1710)ϕand the light exotic candidates,we found that there may exist molecular states composed of f0(1710)ωand f0(1710)ϕ,which correspond to X(2440)and X(2680)observed a few decades ago.The branching fractions of X(2440)and X(2680)to various PV and KKω(ϕ)channels were estimated in the molecular scenario.In addition,the large branching fractions of J/ψ→f0(1710)ω/f0(1710)ϕindicate sizable molecular components in the J/ψstate.Thus,we consider J/ψas the superposition of thecc¯(1S),f0(1710)ω,and f0(1710)ϕmolecular states.These molecular components have a significant impact on the light hadron decays of J/ψ,which may elucidate the long standingρ−πpuzzle.展开更多
In this study, we perform systematic estimations of the radiative decays of the charmed mesons in a modified relativistic quark model. Our estimations indicate that the branching ratios of the processes of D^(0)_(2)(1...In this study, we perform systematic estimations of the radiative decays of the charmed mesons in a modified relativistic quark model. Our estimations indicate that the branching ratios of the processes of D^(0)_(2)(1^(3)P_(2)) →D^(0)(1^(3)S_(1)) γ , D_3^0(1D_3) o D^(0)_(2)(1^(3)P_(2)) γ , D^(0)_(2)(2D_2^) o D_1^(0)(2P_1) γ , D_3^0(2^3D_3) o D^(0)_(2)(2^3P_(2)) γ , and D^(\ast 0)(1^(3)S_(1)) o D^0(1^1S_0) γ are of the order of 10^(-2) , which are sizable to be detected experimentally. Moreover, the branching ratios of some channels, for example, D_1^0(1P_1) o D(1^1S_0)^0 γ , D^0(3^1S_0) o D_1^( 0)(2P^_(1)) γ , and D^0(3^3S_(1)) o D^(0)_(2)(2^3P_(2)) γ , are estimated to be of the order of 10^(-3) , which may be accessible with the accumulation of data in future experiments.展开更多
Inspired by the newly observed X0(2900)and Xj(2900)states at LHCb,the K^(*)D^(*)and KD_(1)interactions are studied in the quasipotential Bethe-Salpeter equation approach combined with the one-boson-exchange model.The ...Inspired by the newly observed X0(2900)and Xj(2900)states at LHCb,the K^(*)D^(*)and KD_(1)interactions are studied in the quasipotential Bethe-Salpeter equation approach combined with the one-boson-exchange model.The bound and virtual states from the interactions are searched for as poles in the complex energy plane of scattering amplitude.A bound state with I(JP)=0(0^(+))and a virtual state with 0(1^(-))are produced from the K^(*)D^(*)interaction and KD_(1)interaction,and can be related to the X_(0)(2900)and Xi(2900)observed at LHCb,respectively.A bound state with I(JP)=0(1^(+))and a virtual state with I(J_(P))=0(2_(+))are also predicted from the KD_(1)interaction,with the same a value,to reproduce the X_(0.1)(2900),which can be searched for in future experiments.展开更多
In this work,we propose the possible assignment of the newly observed X(2239),as well asη(2225),as a molecular state from the interaction of a baryonΛand an antibaryonΛ.With the help of effective Lagrangians,theΛ...In this work,we propose the possible assignment of the newly observed X(2239),as well asη(2225),as a molecular state from the interaction of a baryonΛand an antibaryonΛ.With the help of effective Lagrangians,theΛΛinteraction is described within the one-boson-exchange model withη,η′,ω,ϕ,andσexchanges considered.After inserting the potential kernel into the quasipotential Bethe-Salpeter equation,the bound states from theΛΛinteraction can be studied by searching for the pole of the scattering amplitude.Two loosely bound states with spin parities I^(G)(J^(PC))=0^(+)(0^(−+))and 0^(−)(1^(−−))appear near the threshold with almost the same parameter.The 0^(−)(1^(−−))state can be assigned to X(2239)observed at BESⅢ,which is very close to theΛΛthreshold.The scalar mesonη(2225)can be interpreted as a 0^(+)(0^(−+))state from theΛΛinteraction.The annihilation effect is also discussed through a coupled-channel calculation plus a phenomenological optical potential.It provides large widths to two bound states produced from theΛΛinteraction.The mass of the 1^(−)state is slightly larger than the mass of the 0^(−)state after including the annihilation effect,which is consistent with our assignment of these two states as X(2239)andη(2225),respectively.The results suggest that further investigation is required to understand the structures near theΛΛthreshold,such as X(2239),η(2225),and X(2175).展开更多
Very recently, the Belle and BESIII experiments observed a new charmonium-like state X（3823）, which is a good candidate for tile D-wave charmonium （13D2）. Because the X（3823） is just near the DD＊ threshold, the...Very recently, the Belle and BESIII experiments observed a new charmonium-like state X（3823）, which is a good candidate for tile D-wave charmonium （13D2）. Because the X（3823） is just near the DD＊ threshold, the decay X（3823）→J/ψπ＋π- can be a golden channel to test the significance of coupled-channel effects. In this work, this decay is considered including both the hidden-charm dipion and the usual quantum chromodynamics multipole expansion （QCDME） contributions. The partial decay width, the dipion invari^nt mass spectrum distribution dF[X（3823） →J/ψπ＋π- /dmπ＋π-, and the corresponding dF[X（3823） →J/ψπ＋π-/d cosθ distribution are computed. Many param- eters are determined from exi：sting experimental data, so the results depend mainly only on one unknown phase between the QCDME and hidden-charm dipion amplitudes.展开更多
基金supported by the National Key Research and Development Program of China(No.2022YFA1602200)the National Natural Science Foundation of China(Nos.12341501 and 12405174)the Hefei Comprehensive National Science Center for the strong support on the STCF key technology research project.
文摘Electron-positron colliders operating in the GeV center-of-mass range,or tau-charm energy region,have been proved to enable competitive frontier research due to several unique features.With the progress of high-energy physics in the last two decades,a new-generation Tau-Charm factory,called the Super Tau-Charm Facility(STCF),has been actively promoted by the particle physics community in China.STCF has the potential to address fundamental questions such as the essence of color confinement and the matter-antimatter asymmetry within the next decades.The main design goals of the STCF are a center-of-mass energy ranging from 2 to 7 GeV and a luminosity surpassing 5×10^(34)cm^(−2)s^(−1)that is optimized at a center-of-mass energy of 4 GeV,which is approximately 50 times that of the currently operating Tau-Charm factory-BEPCII.The STCF accelerator has two main parts:a double-ring collider with a crab-waist collision scheme and an injector that provides top-up injections for both electron and positron beams.As a typical third-generation electron-positron circular collider,the STCF accelerator faces many challenges in both accelerator physics and technology.In this paper,the conceptual design of the STCF accelerator complex is presented,including the ongoing efforts and plans for technological research and develop-ment,as well as the required infrastructure.The STCF project aims to secure support from the Chinese central government for its construction during the 15th Five-Year Plan(2026-2030).
基金supported by the China National Funds for Distinguished Young Scientists(Grant No.11825503)the National Key Research and Development Program of China(Grant No.2020YFA0406400)+2 种基金the 111 Project(Grant No.B20063)the National Natural Science Foundation of China(Grant Nos.12047501,12175091,11965016,11775050,and 11775050)CAS Interdisciplinary Innovation Team,and the Fundamental Research Funds for the Central Universities(Grant No.lzujbky-2021-sp24)。
文摘We predict a new physical phenomenon,induced fission-like process and chain reaction of hadronic molecular states.As a molecular state,if induced by a D meson,the X(3872)can split into D■final state which is forbidden due to the spin-parity conservation.The breeding of the D meson of the reaction,such as D^(0)X(3872)→D^(0)■0D^(0),makes the chain reaction of X(3872)matter possible.We estimate the cross section of the D meson induced fission-like process of X(3872)into two D mesons.With very small D^(0) beam momentum of 1 e V,the total cross section reaches an order of 1000 b,and decreases rapidly with the increasing beam momentum.With the transition of D^(*)meson in molecular states to a D meson,the X(3872)can release large energy,which is acquired by the final mesons.The momentum distributions of the final D mesons are analyzed.In the laboratory frame,the spectator D meson in molecular state concentrates in the low momentum area.The energy from the transition from D^(*)to D meson is mainly acquired by two scattered D mesons.The results suggest that the D meson environment will lead to the induced fission-like process and chain reaction of the X(3827).Such a phenomenon can be extended to other hadronic molecular states.
基金Supported by the National Natural Science Foundation of China(Grant No.11775050)the Scientific Research Foundation of Graduate School of Southeast University(Grant No.YBPY2028).
文摘Inspired by the P_(cs)(4459)reported by the LHCb collaboration recently,we investigate the P_(cs)(4459)production from Ξ_(b) decay in a molecular scenario using an effective Lagrangian approach.With different JP assignments to P_(cs)(4459),the magnitude of branching fractions of Ξ_(b)→P_(cs)(4459)K is estimated,which is of the order of 10−4.Together with the decay properties of P_(cs)(4459),the present estimations could be further testified by precise measurements and contribute to a better understanding of the molecular interpretations and the exploration of JP quantum numbers of P_(cs)(4459).
基金Supported by the National Natural Science Foundation of China(11705056,12175037,11947224,11475192,11975245,U1832173)the Key Project of Hunan Provincial Education Department under(21A0039)+3 种基金the State Scholarship Fund of China Scholarship Council(22006725011)the Sino-German CRC 110“Symmetries and the Emergence of Structure in QCD”project by NSFC(12070131001)the Key Research Program of Frontier Sciences,CAS(Y7292610K1)the National Key Research and Development Program of China(2020YFA0406300)。
文摘We adopt the quark pair creation model to investigate the light meson emissions of several charmoniumlike states.The quark pair creation model is applied to four-body systems,and we calculate the pion/kaon emissions of X(4700),Z_(c)(4430),Y(4230),Y(4360),Y(4390),and Y(4660)within compact tetraquark configurations.We find that the pion/kaon decay widths of X(4700)and Z_(c)(4430)the resonances Y(4230),Y(4360),Y(4390),and Y(4660)cay behaviors will provide useful information for future experimental searches and theoretical interpretations.
基金Supported by the National Natural Science Foundation of China(11705056,12175037,11947224,11475192,11975245,U1832173)the Key Project of Hunan Provincial Education Department(21A0039)+3 种基金the State Scholarship Fund of China Scholarship Council(202006725011)the Sino-German CRC 110"Symmetries and the Emergence of Structure in QCD"project by NSFC(12070131001)the Key Research Program of Frontier Sciences,CAS(Y7292610K1)the National Key ResearchandDevelopment Programof China(2020YFA0406300)。
文摘In this paper,we propose to investigate the d_(NΩ)dibaryon production in the K-p-→d_(NΩ)≡0 process by utilizing a kaon beam with a typical momentum of approximately 10 GeV,which may be available at COMPASS,OKA@U-70,and SPS@CERN.The cross sections for K-p-→d_(NΩ)=O are estimated,and in particular,the magnitude of the cross sections is evaluated to be several hundred nanobarns at Pk=20 GeV.Considering that the d_(NΩ)dibaryon dominantly decays into≡Λand≡∑,we also estimate the cross sections for K-p→≡0Λ≡0 and K~p→≡-∑+≡0,where the d_(NΩ)dibaryon can be observed in the invariant mass distributions of≡0Λand≡-∑+,respectively.
基金Supported by National Natural Science Foundation of China(11805160,11747040,11675082)Qinglan Project of Jiangsu Province in 2021。
文摘Motivated by the large branching fractions of J/ψ→f0(1710)ω/f0(1710)ϕand the light exotic candidates,we found that there may exist molecular states composed of f0(1710)ωand f0(1710)ϕ,which correspond to X(2440)and X(2680)observed a few decades ago.The branching fractions of X(2440)and X(2680)to various PV and KKω(ϕ)channels were estimated in the molecular scenario.In addition,the large branching fractions of J/ψ→f0(1710)ω/f0(1710)ϕindicate sizable molecular components in the J/ψstate.Thus,we consider J/ψas the superposition of thecc¯(1S),f0(1710)ω,and f0(1710)ϕmolecular states.These molecular components have a significant impact on the light hadron decays of J/ψ,which may elucidate the long standingρ−πpuzzle.
基金Supported by the National Natural Science Foundation of China(NSFC)(11775050,1275037)。
文摘In this study, we perform systematic estimations of the radiative decays of the charmed mesons in a modified relativistic quark model. Our estimations indicate that the branching ratios of the processes of D^(0)_(2)(1^(3)P_(2)) →D^(0)(1^(3)S_(1)) γ , D_3^0(1D_3) o D^(0)_(2)(1^(3)P_(2)) γ , D^(0)_(2)(2D_2^) o D_1^(0)(2P_1) γ , D_3^0(2^3D_3) o D^(0)_(2)(2^3P_(2)) γ , and D^(\ast 0)(1^(3)S_(1)) o D^0(1^1S_0) γ are of the order of 10^(-2) , which are sizable to be detected experimentally. Moreover, the branching ratios of some channels, for example, D_1^0(1P_1) o D(1^1S_0)^0 γ , D^0(3^1S_0) o D_1^( 0)(2P^_(1)) γ , and D^0(3^3S_(1)) o D^(0)_(2)(2^3P_(2)) γ , are estimated to be of the order of 10^(-3) , which may be accessible with the accumulation of data in future experiments.
基金Supported by the National Natural Science Foundation of China(11675228,11775050)the Fundamental Research Funds for the Central Universities。
文摘Inspired by the newly observed X0(2900)and Xj(2900)states at LHCb,the K^(*)D^(*)and KD_(1)interactions are studied in the quasipotential Bethe-Salpeter equation approach combined with the one-boson-exchange model.The bound and virtual states from the interactions are searched for as poles in the complex energy plane of scattering amplitude.A bound state with I(JP)=0(0^(+))and a virtual state with 0(1^(-))are produced from the K^(*)D^(*)interaction and KD_(1)interaction,and can be related to the X_(0)(2900)and Xi(2900)observed at LHCb,respectively.A bound state with I(JP)=0(1^(+))and a virtual state with I(J_(P))=0(2_(+))are also predicted from the KD_(1)interaction,with the same a value,to reproduce the X_(0.1)(2900),which can be searched for in future experiments.
基金Supported by the National Natural Science Foundation of China(11675228,11775050,61871124)the Fundamental Research Funds for the Central Universities,the national defense Pre-Research foundation of China,by State Key Laboratory of Acoustics,Chinese Academy of Sciences(SKLA201604)Science and Technology on Sonar Laboratory,the Stable Supporting Fund of Acoustic Science and Technology Laboratory。
文摘In this work,we propose the possible assignment of the newly observed X(2239),as well asη(2225),as a molecular state from the interaction of a baryonΛand an antibaryonΛ.With the help of effective Lagrangians,theΛΛinteraction is described within the one-boson-exchange model withη,η′,ω,ϕ,andσexchanges considered.After inserting the potential kernel into the quasipotential Bethe-Salpeter equation,the bound states from theΛΛinteraction can be studied by searching for the pole of the scattering amplitude.Two loosely bound states with spin parities I^(G)(J^(PC))=0^(+)(0^(−+))and 0^(−)(1^(−−))appear near the threshold with almost the same parameter.The 0^(−)(1^(−−))state can be assigned to X(2239)observed at BESⅢ,which is very close to theΛΛthreshold.The scalar mesonη(2225)can be interpreted as a 0^(+)(0^(−+))state from theΛΛinteraction.The annihilation effect is also discussed through a coupled-channel calculation plus a phenomenological optical potential.It provides large widths to two bound states produced from theΛΛinteraction.The mass of the 1^(−)state is slightly larger than the mass of the 0^(−)state after including the annihilation effect,which is consistent with our assignment of these two states as X(2239)andη(2225),respectively.The results suggest that further investigation is required to understand the structures near theΛΛthreshold,such as X(2239),η(2225),and X(2175).
文摘Very recently, the Belle and BESIII experiments observed a new charmonium-like state X（3823）, which is a good candidate for tile D-wave charmonium （13D2）. Because the X（3823） is just near the DD＊ threshold, the decay X（3823）→J/ψπ＋π- can be a golden channel to test the significance of coupled-channel effects. In this work, this decay is considered including both the hidden-charm dipion and the usual quantum chromodynamics multipole expansion （QCDME） contributions. The partial decay width, the dipion invari^nt mass spectrum distribution dF[X（3823） →J/ψπ＋π- /dmπ＋π-, and the corresponding dF[X（3823） →J/ψπ＋π-/d cosθ distribution are computed. Many param- eters are determined from exi：sting experimental data, so the results depend mainly only on one unknown phase between the QCDME and hidden-charm dipion amplitudes.
