In this paper, by using harmonic-oscillator wave functions of different interaction models, i.e. OPE (onepion-exchange model), OPsE (only pseudoscalar meson exchange model), the extended GBE (Goldstone-boson-exchange ...In this paper, by using harmonic-oscillator wave functions of different interaction models, i.e. OPE (onepion-exchange model), OPsE (only pseudoscalar meson exchange model), the extended GBE (Goldstone-boson-exchange model including vector and scalar mesons), and OGE (one-gluon-exchange model), we calculate and compare the strong decays of negative parity N* resonances under 2 GeV. We find that the conventional mixing angles are correct, and GBE and OGE are obviously superior to OPE and OPsE.展开更多
In this work,we apply the effective Lagrangian approach to investigate the two-body strong decay behaviors of the possibleΛ_(c)K^(*)andΣ_(c)K^((*))molecules as predicted in our previous study[Phys.Rev.D 108,054011(2...In this work,we apply the effective Lagrangian approach to investigate the two-body strong decay behaviors of the possibleΛ_(c)K^(*)andΣ_(c)K^((*))molecules as predicted in our previous study[Phys.Rev.D 108,054011(2023)].Our results indicate that the decay width for the coupledΣ_(c)K/Λ_(c)K^(*)/Σ_(c)K^(*)molecule with I(JP)=1/2(1/2-)is on the order of several MeV,with the DsN channel being dominant.For the coupledΛ_(c)K^(*)/Σ_(c)K^(*)molecule with1/2(1/2-,3/2-),the decay widths are on the order of tens of MeV,with the dominant channels beingΣ_(c)K andΣ_(c)^(*)K,respectively.For theΣ_(c)K^(*)molecules with 1/2(1/2-),the decay width can reach one hundred MeV,withΣ_(c)K andΛ_(c)K being the dominant decay channels.The decay widths for theΣ_(c)K^(*)molecules with 1/2(3/2-)an d 3/2(1/2-)are on the order of tens of MeV,with the dominant decay modes beingΣ_(a)^(*)K ndΣ_(c)K,respectively.The branching ratios for all the discussed channels exhibit slight dependence on the binding energies.展开更多
Many P-wave mixing heavy-light 1^＋ states have not yet been discovered by experiment, while others have been discovered but without width information, or with large uncertainties on the widths. In this paper, the str...Many P-wave mixing heavy-light 1^＋ states have not yet been discovered by experiment, while others have been discovered but without width information, or with large uncertainties on the widths. In this paper, the strong decays of the P-wave mixing heavy-light 1^＋ states D^0, D^±, D^±, B^0, B^±： and Bs are studied by the improved Bethe SMpeter （B-S） method with two conditions of mixing angle 0： one is 0 = 35.3°; the other is considering a correction to the mixing angle 0=35.3°＋θ1. Valuable predictions for the strong decay widths are obtained： F（D1^0）=232 MeV, r（D1^0）=21.5 MeV, F（D1^±）=232 MeV, F（D1^±）=21.5 MeV, F（Ds1^±）=0.0101 MeV,Г（Ds1^±l）=0.950 MeV, F（BГ^±＋）=263 MeV, F（B1^±=16.8 MeV, F（B′s1）=0.01987 MeV and F（B,1）=0.412 MeV. It is found that the decay widths of D~ and Bsl are very sensitive to the mixing angle. The results will provide theoretical assistance to future experiments.展开更多
In this work,we study the strong decay of the newly observed P_(cs)(4459),assuming that it is a pureΞcD^(*)molecular state.Considering two possible spin-parity assignments J^(P)=1/2^(−)and J^(P)=3/2^(−),the partial d...In this work,we study the strong decay of the newly observed P_(cs)(4459),assuming that it is a pureΞcD^(*)molecular state.Considering two possible spin-parity assignments J^(P)=1/2^(−)and J^(P)=3/2^(−),the partial decay widths of theΞcD^(*)molecular state into J/ψΛ,D^(−)_(s)Λ^(+)_(c),and DΞ^((′))_(c) final states through hadronic loops are evaluated with the help of the effective Lagrangians.In comparison with the LHCb data,the S-waveD^(*)Ξc molecular with J^(P)=1/2^(−)assignment for P_(cs)(4459)is supported by our study,while the P_(cs)(4459)in spin-parity J^(P)=3/2^(−)case may be explained as an S-wave coupled bound state with lagerΞcD^(*)component.In addition,the calculated partial decay widths with J^(P)=1/2^(−)ΞcD^(*)molecular state picture indicate that allowed decay mode,DΞ′c,may have the biggest branching ratio.The experimental measurements for this strong decay process could be a crucial test for the molecule interpretation of the P_(cs)(4459).展开更多
In this work we calculate the mass spectrum of strangeonium up to the 3D multiplet within a nonrelativistic linear potential quark model.Furthermore,using the obtained wave functions,we also evaluate the strong decays...In this work we calculate the mass spectrum of strangeonium up to the 3D multiplet within a nonrelativistic linear potential quark model.Furthermore,using the obtained wave functions,we also evaluate the strong decays of the strangeonium states with the ^3P_0 model.Based on our successful explanations of the well established states φ(1020) , φ(1680) , h_1(1415) , f'_2(1525) ,and φ_3(1850) ,we further discuss the possible assignments of strangeonium-like states from experiments by combining our theoretical results with observations.It is found that some resonances,such as f_2(2010) and f_2(2150) ,listed by the Particle Data Group,and X(2062) and X(2500) ,newly observed by BESIII,may be interpreted as strangeonium states.The possibility of φ(2170) as a candidate for φ(3S) or φ(2D) cannot be excluded.We expect our results to provide useful references for looking for the missing s\bar{s} states in future experiments.展开更多
Inspired by the newly observed state X＊（3860）, we analyze the strong decay behaviors of some charmonium-like states, X＊（3860）, X（3872）, X（3915）, X（3930） and X（3940）, with the 3P0 model. We carry out our ...Inspired by the newly observed state X＊（3860）, we analyze the strong decay behaviors of some charmonium-like states, X＊（3860）, X（3872）, X（3915）, X（3930） and X（3940）, with the 3P0 model. We carry out our work based on the hypothesis that all of these states are charmonium systems. Our analysis indicates that, as a 0＋＋ charmonium state, X＊（3860） can reproduce the experimental data. As for X（3872）, it can tentatively be interpreted as the mixture of a m cc system and a D＊0D0 molecular state. If we consider X（3940） as a 31S0 state, its total width in the present work is much lower than the experimental result. Thus, the 31S0 charmonium state seems not to be a good candidate for X（3940）. Furthermore, our analysis implies that it is reasonable to assign X（3915） and X（3930） to be the same state, 2＋＋. However, combining our analysis with that in Refs.[14,71], we speculate that X（3915）/X（3930） might also be the mixture of a m cc system and a molecular state.展开更多
In this talk, we briefly review the experimental status of newly observed charmed hadrons during the past years. Then we introduce the theoretical progresses on these charmed hadrons, especially our studies on the str...In this talk, we briefly review the experimental status of newly observed charmed hadrons during the past years. Then we introduce the theoretical progresses on these charmed hadrons, especially our studies on the strong decays of new charmed hadrons during the past one year.展开更多
In the framework of MSSM the probability of Z0-boson decay to chaxginos in a strong electromagnetic field, Z X＋X-, is analyzed. The method of calculations employs exact solutions of relativistic wave equations for ch...In the framework of MSSM the probability of Z0-boson decay to chaxginos in a strong electromagnetic field, Z X＋X-, is analyzed. The method of calculations employs exact solutions of relativistic wave equations for charginos in a crossed electromagnetic field. Analytic expression for the decay width is obtained at an arbitrary value of the parameter which characterizes the external-field strength Fμv and Z%boson momentum qv. The process Z0→ X＋X- is forbidden in a vacuum for the case of relatively heavy charginos： Mx±mz/2. However, in an intense electromagnetic background this reaction could take place in the region of superstrong fields （x〉1）.展开更多
The damage evolution of polycrystalline Al with helium(He)bubbles under strongly decaying shock waves is studied by molecular dynamics simulations.A new damage region is observed near the loading side of the sample,an...The damage evolution of polycrystalline Al with helium(He)bubbles under strongly decaying shock waves is studied by molecular dynamics simulations.A new damage region is observed near the loading side of the sample,and the evolution characteristics and underlying mechanisms are elucidated.The development of damage in the new damage region begins after complete unloading of the incident shock wave and is further enhanced when the tensile stress arrives later.The damage evolution is completely controlled by the expansion-merging of He bubbles,without nucleation–growth of voids.This new damage region can be divided into two sections,each of which exhibits a unique dominant mechanism.The damage in the section closer to the loading side is due to the reverse velocity gradient formed after complete unloading of the incident shock wave,depending on the rate of decrease and the amplitude of the initial peak pressure.A high initial peak pressure that can lead to melting of material near the loading side is a necessary condition for the formation of the new damage region,since a significant reverse velocity gradient can only be established if melting occurs.The dominant mechanism in the section distant from the loading side is the action of tensile stress,associated with the profile of the incident shock wave upon reaching the free surface,which determines the material phase near the free surface.Moreover,the presence of He bubbles is another critical factor for formation of the new damage region,which does not occur in pure Al samples.展开更多
This paper presents novel framework for analyzing unstable composite particles using Green's functions and dispersion relations.As an illustrative example,we explore theρvector meson decay processρ→ππwithin t...This paper presents novel framework for analyzing unstable composite particles using Green's functions and dispersion relations.As an illustrative example,we explore theρvector meson decay processρ→ππwithin the Nambu–Jona-Lasinio(NJL)model.This approach addresses a key limitation of the four-quark interaction description,which adequately describes two-quark bound states but fails to describe decay processes.The Bethe-Salpeter(BS)wave function of theρmeson exhibits time evolution that leads to the physical mass M incorporating a correction??M.This correction depends on the decay widthΓ(M).This work provides crucial insights into the dynamical relationship between resonance masses and their decay properties,addressing a long-standing challenge in hadron physics.The calculated mass and width are in good agreement with the experimental values,demonstrating the effectiveness of this approach for studying unstable hadronic systems beyond conventional bound-state approximations.展开更多
In this talk, we firstly overview the experimental status of Nx（1625）, which is an enhancement structure observed in K-3. invariant mass spectrum of J/ψ → pK-∧. process. Then we present the result of the decay of...In this talk, we firstly overview the experimental status of Nx（1625）, which is an enhancement structure observed in K-3. invariant mass spectrum of J/ψ → pK-∧. process. Then we present the result of the decay of Nx（1625） under the two molecular assumptions, i.e. S-wave∧K- and S-wave ∑0K- molecular states. Several experimental suggestions for Nx （1625） are proposed.展开更多
Inspired by the latest experimental progress,we systematically study the Okubo-Zweig-Iizuka(OZI)-allowed two-body strong decay properties of 1P-,1D-,2S-,and 2P-wave baryons within the j-j coupling scheme in the framew...Inspired by the latest experimental progress,we systematically study the Okubo-Zweig-Iizuka(OZI)-allowed two-body strong decay properties of 1P-,1D-,2S-,and 2P-wave baryons within the j-j coupling scheme in the framework of the quark pair creation model.The calculations indicate the following.(i)Taking the observed statesΛ_(c)(2595)^(+)andΛ_(c)(2625)^(+)as the 1P-waveλ-mode statesΛ_(c)J^(P)=1/2^(-),1>λandΛ_(c)J^(P)=3/2^(-),1>λ,respectively,we can reproduce the experimental data well in theory.(ii)Combined with the measured mass and decay properties ofΛ_(c)(2860)^(+),this excited state can be explained as the 1D-waveλ-mode stateΛ_(c)J^(P)=32+1>λλ.(iii)The newly observed stateΛ_(c)(2910)+may be assigned as one of the 1P-waveρ-mode statesΛ_(c)J^(P)=3/2^(-),2>λorΛ_(c)J^(P)=522>ρ.Meanwhile,we notice that the partial decay width ratio betweenΣ_(c)πandΣ_(c)^(*)πfor the two candidates is significantly different.Hence,experimental progress in this ratio measurement may elucidate the nature ofΛ_(c)(2910)+.(iv)According to the properties ofΛ_(c)(2765)+,we find that the 2S-waveλ-mode stateΛ_(c)1J^(P)=1/2^(+),0>λis a potential candidate.(v)The 2P-waveλ-mode stateΛ_(c)1J^(P)=3/2^(-),1>λis most likely to be a good assignment of the controversial stateΛ_(c)(2940)^(+).Both the total decay width and partial decay ratio between pD^(0)andΣ_(c)πare in good agreement with observations.(vi)In addition,for the missingΛ_(c)excitations,we obtain their strong decay properties and hope these are useful for future experimental exploration.展开更多
Some authors consider the ψ（4415） to be the 4S or 5S excited state of a cc pair. Starting from this assumption, we study the decays of the ψ（4415） to DD, D^＊D^＊, DsDs, Ds^＊Ds^＊, and get the corresponding br...Some authors consider the ψ（4415） to be the 4S or 5S excited state of a cc pair. Starting from this assumption, we study the decays of the ψ（4415） to DD, D^＊D^＊, DsDs, Ds^＊Ds^＊, and get the corresponding branching ratios in terms of the Quark-Pair-Creation （QPC） model. Compared with the experimental data, we find that the results of 4S state agree much better than those of the 5S state. Therefore, it is more reasonable to assume the ψ（4415） to be a 4S state.展开更多
The Babar Collaboration announced two new excited charmed baryons c（3055）^＋ and c（3123）^＋. We study their strong decays assuming they are D-wave states. Some assignments are excluded by comparing our numerical...The Babar Collaboration announced two new excited charmed baryons c（3055）^＋ and c（3123）^＋. We study their strong decays assuming they are D-wave states. Some assignments are excluded by comparing our numerical results with the experimental values of the total widths of c（3055）^＋ and c（3123）^＋. We also suggest some possible decay modes, which will be helpful to determine the properties of c（3055）^＋ and c（3123）^＋.展开更多
Recently,a vector charmonium-like state Y(4626)was observed in the portal of D+sDs1(2536)−.This intrigues an active discussion on the structure of the resonance because it has obvious significance for gaining a better...Recently,a vector charmonium-like state Y(4626)was observed in the portal of D+sDs1(2536)−.This intrigues an active discussion on the structure of the resonance because it has obvious significance for gaining a better understanding on its hadronic structure that contains suitable inner constituents.Therefore,this observation concerns the general theoretical framework about possible structures of exotic states.Since the mass of Y(4626)is slightly above the production threshold of D+sDs1(2536)−,whereas it is below that of D^∗sD^¯s1(2536)with the same quark contents as that of D+sDs1(2536)−,it is natural to conjecture that Y(4626)is a molecular state of D^∗sD^¯s1(2536),as suggested in the literature.Confirming or negating this allegation would shed light on the goal we are concerned with.We calculate the mass spectrum of a system composed of a vector meson and an axial vector i.e.,D^∗sD^¯s1(2536)within the framework of the Bethe-Salpeter equations.Our numerical results show that the dimensionless parameterλin the form factor,which is phenomenologically introduced to every vertex,is far beyond the reasonable range for inducing even a very small binding energyΔE.It implies that the D^∗sD^¯s1(2536)system cannot exist in the nature as a hadronic molecule in this model.Therefore,we may not be able to assume the resonance Y(4626)to be a bound state of D^∗sD^¯s1(2536),and instead,it could be attributed to something else,such as a tetraquark.展开更多
In this study,by combining the equal spacing rule with recent observations of Ω_(C)(X)and Ξ_(C)(X)baryons,we predict the spectrum of the low-lying λ-mode 1P-wave excited ∑_(c) states.Furthermore,their strong decay...In this study,by combining the equal spacing rule with recent observations of Ω_(C)(X)and Ξ_(C)(X)baryons,we predict the spectrum of the low-lying λ-mode 1P-wave excited ∑_(c) states.Furthermore,their strong decay properties are predicted using the chiral quark model and the nature of∑_(c)(2800)is investigated by analyzing the invariant mass spectrum.The ∑_(c)(2800)structure observed in the Λ_(c)πmass spectrum was found to potentially arise from two overlapping P-wave resonances,∑_(c)(2813)3/2^(-)and ∑_(c)(2840)5/2^(-).These resonances have similar decay widths of Г〜40 MeV and predominantly decay into the Λ_(c)π channel.The ∑_(c)(2755)1/2^(-)state is likely to be a very narrow state with a width of Г〜15 MeV,with its decays almost saturated by the Λ_(c)π channel.Additionally,evidence of the Lc(2755)1/2^(-)resonance as a very narrow peak may be seen in the Λ_(c)π invariant mass spectrum.The other two P-wave states,∑_(c)(2746)1/2^(-)and ∑_(c)(2796)3/2^(-),are relatively narrow states with similar widths of「〜30 MeV and predominantly decay into ∑_(c)π and ∑^(*)_(c)π,respectively.This study can provide useful references for discovering these low-lying P-wave states in forthcoming experiments.展开更多
We discuss a possible interpretation of the open charm mesons D＊s0 （2317）,D s1 （2460） and the hidden charm mesons X（3872）,Y（3940） and Y（4140） as hadron molecules.Using a phenomenological Lagrangian approach...We discuss a possible interpretation of the open charm mesons D＊s0 （2317）,D s1 （2460） and the hidden charm mesons X（3872）,Y（3940） and Y（4140） as hadron molecules.Using a phenomenological Lagrangian approach we review the strong and radiative decays of the D＊ s0 （2317） and D s1 （2460） states.The X（3872） is assumed to consist dominantly of molecular hadronic components with an additional small admixture of a charmonium configuration.Determing the radiative （γJ/ψ and γψ（2s）） and strong （J/ψ2π and J/ψ3π） decay modes we show that the present experimental observation is consistent with the molecular structure assumption of the X（3872）.Finally,we give evidence for molecular interpretations of the Y（3940） and Y（4140） related to the observed strong decay modes J/ψ＋ω or J/ψ＋φ,respectively.展开更多
文摘In this paper, by using harmonic-oscillator wave functions of different interaction models, i.e. OPE (onepion-exchange model), OPsE (only pseudoscalar meson exchange model), the extended GBE (Goldstone-boson-exchange model including vector and scalar mesons), and OGE (one-gluon-exchange model), we calculate and compare the strong decays of negative parity N* resonances under 2 GeV. We find that the conventional mixing angles are correct, and GBE and OGE are obviously superior to OPE and OPsE.
基金Supported by the National Natural Science Foundation of China(12305139)the Xiaoxiang Scholars Programma of Hunan Normal University。
文摘In this work,we apply the effective Lagrangian approach to investigate the two-body strong decay behaviors of the possibleΛ_(c)K^(*)andΣ_(c)K^((*))molecules as predicted in our previous study[Phys.Rev.D 108,054011(2023)].Our results indicate that the decay width for the coupledΣ_(c)K/Λ_(c)K^(*)/Σ_(c)K^(*)molecule with I(JP)=1/2(1/2-)is on the order of several MeV,with the DsN channel being dominant.For the coupledΛ_(c)K^(*)/Σ_(c)K^(*)molecule with1/2(1/2-,3/2-),the decay widths are on the order of tens of MeV,with the dominant channels beingΣ_(c)K andΣ_(c)^(*)K,respectively.For theΣ_(c)K^(*)molecules with 1/2(1/2-),the decay width can reach one hundred MeV,withΣ_(c)K andΛ_(c)K being the dominant decay channels.The decay widths for theΣ_(c)K^(*)molecules with 1/2(3/2-)an d 3/2(1/2-)are on the order of tens of MeV,with the dominant decay modes beingΣ_(a)^(*)K ndΣ_(c)K,respectively.The branching ratios for all the discussed channels exhibit slight dependence on the binding energies.
基金Supported by the National Natural Science Foundation of China(NSFC)(11405004,11405037,11505039,11575048)the Key Scientific Research Projects in 2017 at North Minzu University(2017KJ11)+1 种基金Ningxia First-Class Discipline and Scientific Research Projects(Electronic Science and Technology)(NXYLXK2017A07)the Fundamental Research Funds for the Central Universities,North Minzu University(2018XYZDX08)
文摘Many P-wave mixing heavy-light 1^＋ states have not yet been discovered by experiment, while others have been discovered but without width information, or with large uncertainties on the widths. In this paper, the strong decays of the P-wave mixing heavy-light 1^＋ states D^0, D^±, D^±, B^0, B^±： and Bs are studied by the improved Bethe SMpeter （B-S） method with two conditions of mixing angle 0： one is 0 = 35.3°; the other is considering a correction to the mixing angle 0=35.3°＋θ1. Valuable predictions for the strong decay widths are obtained： F（D1^0）=232 MeV, r（D1^0）=21.5 MeV, F（D1^±）=232 MeV, F（D1^±）=21.5 MeV, F（Ds1^±）=0.0101 MeV,Г（Ds1^±l）=0.950 MeV, F（BГ^±＋）=263 MeV, F（B1^±=16.8 MeV, F（B′s1）=0.01987 MeV and F（B,1）=0.412 MeV. It is found that the decay widths of D~ and Bsl are very sensitive to the mixing angle. The results will provide theoretical assistance to future experiments.
基金supported by the Science and Technology Research Program of Chongqing Municipal Education Commission(Grant No.KJQN201800510)the Opened Fund of the State Key Laboratory on Integrated Optoelectronics(Grant No.IOSKL2017KF19)+2 种基金the support from the Development and Exchange Platform for the Theoretic Physics of Southwest Jiaotong University(Grant Nos.11947404,and 12047576)Fundamental Research Funds for the Central Universities(Grant No.2682020CX70)National Natural Science Foundation of China(Grant No.12005177)。
文摘In this work,we study the strong decay of the newly observed P_(cs)(4459),assuming that it is a pureΞcD^(*)molecular state.Considering two possible spin-parity assignments J^(P)=1/2^(−)and J^(P)=3/2^(−),the partial decay widths of theΞcD^(*)molecular state into J/ψΛ,D^(−)_(s)Λ^(+)_(c),and DΞ^((′))_(c) final states through hadronic loops are evaluated with the help of the effective Lagrangians.In comparison with the LHCb data,the S-waveD^(*)Ξc molecular with J^(P)=1/2^(−)assignment for P_(cs)(4459)is supported by our study,while the P_(cs)(4459)in spin-parity J^(P)=3/2^(−)case may be explained as an S-wave coupled bound state with lagerΞcD^(*)component.In addition,the calculated partial decay widths with J^(P)=1/2^(−)ΞcD^(*)molecular state picture indicate that allowed decay mode,DΞ′c,may have the biggest branching ratio.The experimental measurements for this strong decay process could be a crucial test for the molecule interpretation of the P_(cs)(4459).
基金Supported by the National Natural Science Foundation of China(U1832173,11775078,11705056,11405053)。
文摘In this work we calculate the mass spectrum of strangeonium up to the 3D multiplet within a nonrelativistic linear potential quark model.Furthermore,using the obtained wave functions,we also evaluate the strong decays of the strangeonium states with the ^3P_0 model.Based on our successful explanations of the well established states φ(1020) , φ(1680) , h_1(1415) , f'_2(1525) ,and φ_3(1850) ,we further discuss the possible assignments of strangeonium-like states from experiments by combining our theoretical results with observations.It is found that some resonances,such as f_2(2010) and f_2(2150) ,listed by the Particle Data Group,and X(2062) and X(2500) ,newly observed by BESIII,may be interpreted as strangeonium states.The possibility of φ(2170) as a candidate for φ(3S) or φ(2D) cannot be excluded.We expect our results to provide useful references for looking for the missing s\bar{s} states in future experiments.
基金Supported by the Fundamental Research Funds for the Central Universities(2016MS133)
文摘Inspired by the newly observed state X＊（3860）, we analyze the strong decay behaviors of some charmonium-like states, X＊（3860）, X（3872）, X（3915）, X（3930） and X（3940）, with the 3P0 model. We carry out our work based on the hypothesis that all of these states are charmonium systems. Our analysis indicates that, as a 0＋＋ charmonium state, X＊（3860） can reproduce the experimental data. As for X（3872）, it can tentatively be interpreted as the mixture of a m cc system and a D＊0D0 molecular state. If we consider X（3940） as a 31S0 state, its total width in the present work is much lower than the experimental result. Thus, the 31S0 charmonium state seems not to be a good candidate for X（3940）. Furthermore, our analysis implies that it is reasonable to assign X（3915） and X（3930） to be the same state, 2＋＋. However, combining our analysis with that in Refs.[14,71], we speculate that X（3915）/X（3930） might also be the mixture of a m cc system and a molecular state.
基金Supported by National Natural Science Foundation of China (10421503,10625521,10705001)China Postdoctoral Science Foundation (20060400376)
文摘In this talk, we briefly review the experimental status of newly observed charmed hadrons during the past years. Then we introduce the theoretical progresses on these charmed hadrons, especially our studies on the strong decays of new charmed hadrons during the past one year.
文摘In the framework of MSSM the probability of Z0-boson decay to chaxginos in a strong electromagnetic field, Z X＋X-, is analyzed. The method of calculations employs exact solutions of relativistic wave equations for charginos in a crossed electromagnetic field. Analytic expression for the decay width is obtained at an arbitrary value of the parameter which characterizes the external-field strength Fμv and Z%boson momentum qv. The process Z0→ X＋X- is forbidden in a vacuum for the case of relatively heavy charginos： Mx±mz/2. However, in an intense electromagnetic background this reaction could take place in the region of superstrong fields （x〉1）.
基金supported by the National Natural Science Foundation of China(Grant No.12172063).
文摘The damage evolution of polycrystalline Al with helium(He)bubbles under strongly decaying shock waves is studied by molecular dynamics simulations.A new damage region is observed near the loading side of the sample,and the evolution characteristics and underlying mechanisms are elucidated.The development of damage in the new damage region begins after complete unloading of the incident shock wave and is further enhanced when the tensile stress arrives later.The damage evolution is completely controlled by the expansion-merging of He bubbles,without nucleation–growth of voids.This new damage region can be divided into two sections,each of which exhibits a unique dominant mechanism.The damage in the section closer to the loading side is due to the reverse velocity gradient formed after complete unloading of the incident shock wave,depending on the rate of decrease and the amplitude of the initial peak pressure.A high initial peak pressure that can lead to melting of material near the loading side is a necessary condition for the formation of the new damage region,since a significant reverse velocity gradient can only be established if melting occurs.The dominant mechanism in the section distant from the loading side is the action of tensile stress,associated with the profile of the incident shock wave upon reaching the free surface,which determines the material phase near the free surface.Moreover,the presence of He bubbles is another critical factor for formation of the new damage region,which does not occur in pure Al samples.
基金Supported by the Fostering Program in Disciplines Possessing Novel Features for Natural Science of Sichuan University(2020SCUNL209)。
文摘This paper presents novel framework for analyzing unstable composite particles using Green's functions and dispersion relations.As an illustrative example,we explore theρvector meson decay processρ→ππwithin the Nambu–Jona-Lasinio(NJL)model.This approach addresses a key limitation of the four-quark interaction description,which adequately describes two-quark bound states but fails to describe decay processes.The Bethe-Salpeter(BS)wave function of theρmeson exhibits time evolution that leads to the physical mass M incorporating a correction??M.This correction depends on the decay widthΓ(M).This work provides crucial insights into the dynamical relationship between resonance masses and their decay properties,addressing a long-standing challenge in hadron physics.The calculated mass and width are in good agreement with the experimental values,demonstrating the effectiveness of this approach for studying unstable hadronic systems beyond conventional bound-state approximations.
基金Supported by National Natural Science Foundation of China (10705001)
文摘In this talk, we firstly overview the experimental status of Nx（1625）, which is an enhancement structure observed in K-3. invariant mass spectrum of J/ψ → pK-∧. process. Then we present the result of the decay of Nx（1625） under the two molecular assumptions, i.e. S-wave∧K- and S-wave ∑0K- molecular states. Several experimental suggestions for Nx （1625） are proposed.
基金Supported by the National Natural Science Foundation of China(12005013,12175065,12235018,11947048)。
文摘Inspired by the latest experimental progress,we systematically study the Okubo-Zweig-Iizuka(OZI)-allowed two-body strong decay properties of 1P-,1D-,2S-,and 2P-wave baryons within the j-j coupling scheme in the framework of the quark pair creation model.The calculations indicate the following.(i)Taking the observed statesΛ_(c)(2595)^(+)andΛ_(c)(2625)^(+)as the 1P-waveλ-mode statesΛ_(c)J^(P)=1/2^(-),1>λandΛ_(c)J^(P)=3/2^(-),1>λ,respectively,we can reproduce the experimental data well in theory.(ii)Combined with the measured mass and decay properties ofΛ_(c)(2860)^(+),this excited state can be explained as the 1D-waveλ-mode stateΛ_(c)J^(P)=32+1>λλ.(iii)The newly observed stateΛ_(c)(2910)+may be assigned as one of the 1P-waveρ-mode statesΛ_(c)J^(P)=3/2^(-),2>λorΛ_(c)J^(P)=522>ρ.Meanwhile,we notice that the partial decay width ratio betweenΣ_(c)πandΣ_(c)^(*)πfor the two candidates is significantly different.Hence,experimental progress in this ratio measurement may elucidate the nature ofΛ_(c)(2910)+.(iv)According to the properties ofΛ_(c)(2765)+,we find that the 2S-waveλ-mode stateΛ_(c)1J^(P)=1/2^(+),0>λis a potential candidate.(v)The 2P-waveλ-mode stateΛ_(c)1J^(P)=3/2^(-),1>λis most likely to be a good assignment of the controversial stateΛ_(c)(2940)^(+).Both the total decay width and partial decay ratio between pD^(0)andΣ_(c)πare in good agreement with observations.(vi)In addition,for the missingΛ_(c)excitations,we obtain their strong decay properties and hope these are useful for future experimental exploration.
基金Natural Science Fund of Hebei Province (A2005000090,E2005000129)Fund of Education Department of Hebei Province (2007409)Research Fund for Doctoral Programs of Hebei University (Y2006081)
文摘Some authors consider the ψ（4415） to be the 4S or 5S excited state of a cc pair. Starting from this assumption, we study the decays of the ψ（4415） to DD, D^＊D^＊, DsDs, Ds^＊Ds^＊, and get the corresponding branching ratios in terms of the Quark-Pair-Creation （QPC） model. Compared with the experimental data, we find that the results of 4S state agree much better than those of the 5S state. Therefore, it is more reasonable to assume the ψ（4415） to be a 4S state.
基金National Natural Science Foundation of China(10421503,10625521,10705001)China Postdoctoral Science Foundation(20060400376)
文摘The Babar Collaboration announced two new excited charmed baryons c（3055）^＋ and c（3123）^＋. We study their strong decays assuming they are D-wave states. Some assignments are excluded by comparing our numerical results with the experimental values of the total widths of c（3055）^＋ and c（3123）^＋. We also suggest some possible decay modes, which will be helpful to determine the properties of c（3055）^＋ and c（3123）^＋.
基金Supported by the National Natural Science Foundation of China(11375128,11675082,11735010,11975165)。
文摘Recently,a vector charmonium-like state Y(4626)was observed in the portal of D+sDs1(2536)−.This intrigues an active discussion on the structure of the resonance because it has obvious significance for gaining a better understanding on its hadronic structure that contains suitable inner constituents.Therefore,this observation concerns the general theoretical framework about possible structures of exotic states.Since the mass of Y(4626)is slightly above the production threshold of D+sDs1(2536)−,whereas it is below that of D^∗sD^¯s1(2536)with the same quark contents as that of D+sDs1(2536)−,it is natural to conjecture that Y(4626)is a molecular state of D^∗sD^¯s1(2536),as suggested in the literature.Confirming or negating this allegation would shed light on the goal we are concerned with.We calculate the mass spectrum of a system composed of a vector meson and an axial vector i.e.,D^∗sD^¯s1(2536)within the framework of the Bethe-Salpeter equations.Our numerical results show that the dimensionless parameterλin the form factor,which is phenomenologically introduced to every vertex,is far beyond the reasonable range for inducing even a very small binding energyΔE.It implies that the D^∗sD^¯s1(2536)system cannot exist in the nature as a hadronic molecule in this model.Therefore,we may not be able to assume the resonance Y(4626)to be a bound state of D^∗sD^¯s1(2536),and instead,it could be attributed to something else,such as a tetraquark.
基金Supported by the National Natural Science Foundation of China(U1832173,11775078)Scientific and Technological Innovation Programs of Higher Education Institutions of Shanxi Province,China(2020L0617)。
文摘In this study,by combining the equal spacing rule with recent observations of Ω_(C)(X)and Ξ_(C)(X)baryons,we predict the spectrum of the low-lying λ-mode 1P-wave excited ∑_(c) states.Furthermore,their strong decay properties are predicted using the chiral quark model and the nature of∑_(c)(2800)is investigated by analyzing the invariant mass spectrum.The ∑_(c)(2800)structure observed in the Λ_(c)πmass spectrum was found to potentially arise from two overlapping P-wave resonances,∑_(c)(2813)3/2^(-)and ∑_(c)(2840)5/2^(-).These resonances have similar decay widths of Г〜40 MeV and predominantly decay into the Λ_(c)π channel.The ∑_(c)(2755)1/2^(-)state is likely to be a very narrow state with a width of Г〜15 MeV,with its decays almost saturated by the Λ_(c)π channel.Additionally,evidence of the Lc(2755)1/2^(-)resonance as a very narrow peak may be seen in the Λ_(c)π invariant mass spectrum.The other two P-wave states,∑_(c)(2746)1/2^(-)and ∑_(c)(2796)3/2^(-),are relatively narrow states with similar widths of「〜30 MeV and predominantly decay into ∑_(c)π and ∑^(*)_(c)π,respectively.This study can provide useful references for discovering these low-lying P-wave states in forthcoming experiments.
基金Supported by Deutsche Forschungsgemeinschaft Contract No.FA67/31-2 and No.GRK683also part of the European Community-Research Infrastructure Integrating Activity 'Study of Strongly Interacting Matter' (acronym Hadron- Physics2,Grant Agreement No.227431)+1 种基金Russian President grant 'Scientific Schools' No.3400.2010.2Russian Science and Innovations Federal Agency contract No.02.740.11.0238
文摘We discuss a possible interpretation of the open charm mesons D＊s0 （2317）,D s1 （2460） and the hidden charm mesons X（3872）,Y（3940） and Y（4140） as hadron molecules.Using a phenomenological Lagrangian approach we review the strong and radiative decays of the D＊ s0 （2317） and D s1 （2460） states.The X（3872） is assumed to consist dominantly of molecular hadronic components with an additional small admixture of a charmonium configuration.Determing the radiative （γJ/ψ and γψ（2s）） and strong （J/ψ2π and J/ψ3π） decay modes we show that the present experimental observation is consistent with the molecular structure assumption of the X（3872）.Finally,we give evidence for molecular interpretations of the Y（3940） and Y（4140） related to the observed strong decay modes J/ψ＋ω or J/ψ＋φ,respectively.
