There have been extended and heated discussions on the nature of the two exotic states,Z_(c)(3900)and Z_(sc)(3985),particularly whether they are near-threshold resonances,virtual states,or bound states.In this work,we...There have been extended and heated discussions on the nature of the two exotic states,Z_(c)(3900)and Z_(sc)(3985),particularly whether they are near-threshold resonances,virtual states,or bound states.In this work,we demonstrate for the first time that the femtoscopic technique can be employed to distinguish between these three scenarios.More concretely,based on the Koonin-Pratt formula with a Gaussian source,we show that the low-momentum D^(0)D^(*-)/D^(0)D_(s)^(*-)correlation functions significantly differ in the three scenarios.The high-momentum results exhibit distinct characteristics in the resonant and virtual state scenarios,especially in small collision systems of 1 fm,as produced in pp collisions at the LHC.We hope that these discoveries will stimulate further experimental studies and help clarify the nature of the many exotic states that have been discovered.展开更多
The Λ(1405) has been one of the most controversial exotic baryons.If the Λ(1405)possesses a two-pole molecular structure,these poles are expected to evolve differently towards the SU(3)limit.From an analysis of a re...The Λ(1405) has been one of the most controversial exotic baryons.If the Λ(1405)possesses a two-pole molecular structure,these poles are expected to evolve differently towards the SU(3)limit.From an analysis of a recent LQCD simulation on theπΣ-KN scattering for I=0 and the study of the quark mass dependence of the octet baryon masses,we determine for the first time the trajectories of these poles towards the symmetric point over the Tr[M]=C trajectory accurately.At m_(π)■200 MeV,our results are consistent with the lattice simulations,and the extrapolations to the physical point,based on the NLO chiral Lagrangians,agree well with existing experimental analyses.We predict qualitatively similar trajectories at LO and up to NLO,consistent with the LO interaction’s dominance.At the SU(3)symmetric point of this trajectory,both poles are on the physical sheet,and the lower pole is located at E^((1))=1573(6)(6)MeV,becoming a SU(3)singlet,while the higher pole at E^((8a))=1589(7)(5)MeV couples to the octet representation.Moreover,we make predictions in I=1 for theΣ^(*)resonance.We find a resonance pole that evolves into a bound state around m_(π)=415 MeV in this sector.The results presented here are crucial to shed light on the molecular nature of exotic strange baryon resonances and can be tested in future LQCD simulations.展开更多
The Circular Electron Positron Collider(CEPC)is a large scientific project initiated and hosted by China,fostered through extensive collaboration with international partners.The complex comprises four accelerators:a 3...The Circular Electron Positron Collider(CEPC)is a large scientific project initiated and hosted by China,fostered through extensive collaboration with international partners.The complex comprises four accelerators:a 30 GeV Linac,a 1.1 GeV Damping Ring,a Booster capable of achieving energies up to 180 GeV,and a Collider operating at varying energy modes(Z,W,H,and tt).The Linac and Damping Ring are situated on the surface,while the subterranean Booster and Collider are housed in a 100 km circumference underground tunnel,strategically accommodating future expansion with provisions for a potential Super Proton Proton Collider(SPPC).The CEPC primarily serves as a Higgs factory.In its baseline design with synchrotron radiation(SR)power of 30 MW per beam,it can achieve a luminosity of 5×10^(34)cm^(-2)s^(-1)per interaction point(IP),resulting in an integrated luminosity of 13 ab^(-1)for two IPs over a decade,producing 2.6 million Higgs bosons.Increasing the SR power to 50 MW per beam expands the CEPC's capability to generate 4.3 million Higgs bosons,facilitating precise measurements of Higgs coupling at sub-percent levels,exceeding the precision expected from the HL-LHC by an order of magnitude.This Technical Design Report(TDR)follows the Preliminary Conceptual Design Report(Pre-CDR,2015)and the Conceptual Design Report(CDR,2018),comprehensively detailing the machine's layout,performance metrics,physical design and analysis,technical systems design,R&D and prototyping efforts,and associated civil engineering aspects.Additionally,it includes a cost estimate and a preliminary construction timeline,establishing a framework for forthcoming engineering design phase and site selection procedures.Construction is anticipated to begin around 2027-2028,pending government approval,with an estimated duration of 8 years.The commencement of experiments and data collection could potentially be initiated in the mid-2030s.展开更多
Weak radiative hyperon decays,important to test the strong interaction and relevant in searches for beyond the standard model physics,have remained puzzling both experimentally and theoretically for a long time.The re...Weak radiative hyperon decays,important to test the strong interaction and relevant in searches for beyond the standard model physics,have remained puzzling both experimentally and theoretically for a long time.The recently updated branching fraction and first measurement of the asymmetry parameter of Λ→nγ by the BESIII Collaboration further exacerbate the issue,as none of the existing predictions can describe the data.We show in this work that the covariant baryon chiral perturbation theory,with constraints from the latest measurements of hyperon non-leptonic decays,can well describe the BESIII data.The predicted branching fraction and asymmetry parameter for Ξ→Σγ are also in agreement with the experimental data.We note that a more precise measurement of the asymmetry parameter,which is strongly constrained by chiral symmetry and related with that of Σ→pγ,is crucial to test Hara’s theorem.We further predict the branching fraction and asymmetry parameter of Σ~0→nγ,whose future measurement can serve as a highly nontrivial check on our understanding of weak radiative hyperon decays and on the covariant baryon chiral perturbation theory.展开更多
基金supported by the National Key R&D Program of China(2023YFA1606703)the National Natural Science Foundation of China(12435007)+2 种基金support from the National Natural Science Foundation of China(12405133,12347180)China Postdoctoral Science Foundation(2023M740189)the Postdoctoral Fellowship Program of CPSF(GZC20233381).
文摘There have been extended and heated discussions on the nature of the two exotic states,Z_(c)(3900)and Z_(sc)(3985),particularly whether they are near-threshold resonances,virtual states,or bound states.In this work,we demonstrate for the first time that the femtoscopic technique can be employed to distinguish between these three scenarios.More concretely,based on the Koonin-Pratt formula with a Gaussian source,we show that the low-momentum D^(0)D^(*-)/D^(0)D_(s)^(*-)correlation functions significantly differ in the three scenarios.The high-momentum results exhibit distinct characteristics in the resonant and virtual state scenarios,especially in small collision systems of 1 fm,as produced in pp collisions at the LHC.We hope that these discoveries will stimulate further experimental studies and help clarify the nature of the many exotic states that have been discovered.
基金supported by the Spanish Ministerio de Economia y Competitividad(MINECO),European FEDER funds(FIS2017-84038-C2-1-P B,PID2020-112777 GB-I00),Generalitat Valenciana(PROMETEO/2020/023)the European Union Horizon 2020 research and innovation program(H2020-INFRAIA-20181)+4 种基金grant agreement(824093)of the STRONG-2020 projectsupport from the ESGENT program(ESGENT/018/2024)the PROMETEU program(CIPROM/2023/59),of the Generalitat Valenciana,and also from the Spanish Ministerio de Economia y Competitividad and the European Union(NextGenerationEU/PRTR)by the grant(CNS2022-13614)support from the National Key R&D Program of China(2023YFA1606703)the National Natural Science Foundation of China(12435007)。
文摘The Λ(1405) has been one of the most controversial exotic baryons.If the Λ(1405)possesses a two-pole molecular structure,these poles are expected to evolve differently towards the SU(3)limit.From an analysis of a recent LQCD simulation on theπΣ-KN scattering for I=0 and the study of the quark mass dependence of the octet baryon masses,we determine for the first time the trajectories of these poles towards the symmetric point over the Tr[M]=C trajectory accurately.At m_(π)■200 MeV,our results are consistent with the lattice simulations,and the extrapolations to the physical point,based on the NLO chiral Lagrangians,agree well with existing experimental analyses.We predict qualitatively similar trajectories at LO and up to NLO,consistent with the LO interaction’s dominance.At the SU(3)symmetric point of this trajectory,both poles are on the physical sheet,and the lower pole is located at E^((1))=1573(6)(6)MeV,becoming a SU(3)singlet,while the higher pole at E^((8a))=1589(7)(5)MeV couples to the octet representation.Moreover,we make predictions in I=1 for theΣ^(*)resonance.We find a resonance pole that evolves into a bound state around m_(π)=415 MeV in this sector.The results presented here are crucial to shed light on the molecular nature of exotic strange baryon resonances and can be tested in future LQCD simulations.
基金support from diverse funding sources,including the National Key Program for S&T Research and Development of the Ministry of Science and Technology(MOST),Yifang Wang's Science Studio of the Ten Thousand Talents Project,the CAS Key Foreign Cooperation Grant,the National Natural Science Foundation of China(NSFC)Beijing Municipal Science&Technology Commission,the CAS Focused Science Grant,the IHEP Innovation Grant,the CAS Lead Special Training Programthe CAS Center for Excellence in Particle Physics,the CAS International Partnership Program,and the CAS/SAFEA International Partnership Program for Creative Research Teams.
文摘The Circular Electron Positron Collider(CEPC)is a large scientific project initiated and hosted by China,fostered through extensive collaboration with international partners.The complex comprises four accelerators:a 30 GeV Linac,a 1.1 GeV Damping Ring,a Booster capable of achieving energies up to 180 GeV,and a Collider operating at varying energy modes(Z,W,H,and tt).The Linac and Damping Ring are situated on the surface,while the subterranean Booster and Collider are housed in a 100 km circumference underground tunnel,strategically accommodating future expansion with provisions for a potential Super Proton Proton Collider(SPPC).The CEPC primarily serves as a Higgs factory.In its baseline design with synchrotron radiation(SR)power of 30 MW per beam,it can achieve a luminosity of 5×10^(34)cm^(-2)s^(-1)per interaction point(IP),resulting in an integrated luminosity of 13 ab^(-1)for two IPs over a decade,producing 2.6 million Higgs bosons.Increasing the SR power to 50 MW per beam expands the CEPC's capability to generate 4.3 million Higgs bosons,facilitating precise measurements of Higgs coupling at sub-percent levels,exceeding the precision expected from the HL-LHC by an order of magnitude.This Technical Design Report(TDR)follows the Preliminary Conceptual Design Report(Pre-CDR,2015)and the Conceptual Design Report(CDR,2018),comprehensively detailing the machine's layout,performance metrics,physical design and analysis,technical systems design,R&D and prototyping efforts,and associated civil engineering aspects.Additionally,it includes a cost estimate and a preliminary construction timeline,establishing a framework for forthcoming engineering design phase and site selection procedures.Construction is anticipated to begin around 2027-2028,pending government approval,with an estimated duration of 8 years.The commencement of experiments and data collection could potentially be initiated in the mid-2030s.
基金supported in part by the National Natural Science Foundation of China (11735003, 11975041, and11961141004)support from the National Natural Science Foundation of China (12147145)+2 种基金support from the National Natural Science Foundation of China (12105006)Project funded by China Postdoctoral Science Foundation (2021M700343)China Postdoctoral Science Foundation (2021M690008)
文摘Weak radiative hyperon decays,important to test the strong interaction and relevant in searches for beyond the standard model physics,have remained puzzling both experimentally and theoretically for a long time.The recently updated branching fraction and first measurement of the asymmetry parameter of Λ→nγ by the BESIII Collaboration further exacerbate the issue,as none of the existing predictions can describe the data.We show in this work that the covariant baryon chiral perturbation theory,with constraints from the latest measurements of hyperon non-leptonic decays,can well describe the BESIII data.The predicted branching fraction and asymmetry parameter for Ξ→Σγ are also in agreement with the experimental data.We note that a more precise measurement of the asymmetry parameter,which is strongly constrained by chiral symmetry and related with that of Σ→pγ,is crucial to test Hara’s theorem.We further predict the branching fraction and asymmetry parameter of Σ~0→nγ,whose future measurement can serve as a highly nontrivial check on our understanding of weak radiative hyperon decays and on the covariant baryon chiral perturbation theory.
