By using the ^(3)P_(0) pair creation model,we provide a detailed derivation of the transition matrix for a baryon decaying into a meson-baryon system.This analysis was successfully conducted for a meson in[J.Segovia,D...By using the ^(3)P_(0) pair creation model,we provide a detailed derivation of the transition matrix for a baryon decaying into a meson-baryon system.This analysis was successfully conducted for a meson in[J.Segovia,D.R.Entem,and F.Fernandez,Phys.Lett.B 715,322(2012),and we extend the same formalism to the baryon sector,focusing on the △(1232)→πN strong decay width because all hadrons involved in the reaction are very well established,the two hadrons in the final state are stable and require no further analysis,all quarks are light and thus equivalent,and the decay width of the process is relatively well measured.Utilizing a very common Rayleigh-Ritz variational method to solve the 2-and 3-body Schodinger bound-state equation in which the hadron's radial wave functions are expanded in terms of a Gaussian basis,we can relate the expression of the invariant matrix element with the mean-square radii of hadrons involved in the decay.We use their experimental measures in such a way that only the strength of the quark-antiquark pair creation from the vacuum is a free parameter.This is then taken from our previous study on strong decay widths in the meson sector[J.Segovia,D.R.Entem,and F.Fernandez,Phys.Lett.B 715,322(2012),and the obtained results are compatible with the experimental results for the calculated △(1232)→πN decay width.Despite requiring the calculation of additional baryon strong decays,a feasible avenue towards a unified description of both baryon and meson strong decay widths within a single constituent quark model framework may be attainable.Finally,this research has been developed to lay the foundation for a novel raft of applications to exotic hadrons,i.e.,the description of the baryon's coupling to meson-baryon thresholds,one of the mechanisms that is considered to be responsible for providing either a large renormalization to naive states or genuine dynamicallygenerated meson-baryon molecules.展开更多
All existing experimental evidence for the bound state nature of X(3872)relies on observing its decay products,which are measured with a finite experimental mass resolution that is typically△m≥2 MeV,and much larger ...All existing experimental evidence for the bound state nature of X(3872)relies on observing its decay products,which are measured with a finite experimental mass resolution that is typically△m≥2 MeV,and much larger than its alleged binding energy,BX=0.00(18)MeV.On the other hand,we have found recently that there is a clear cancellation in the 1^++channel of the invariant DD^*mass around the threshold between continuum and the bound state.This is very much like a similar cancellation in the proton-neutron continuum with the deuteron in the 1^++channel.Based on comparative fits with a common Tsallis distribution of the experimental cross-sections for prompt production of deuterons and X(3872)in pp collisions with a finite pT,we find a strong argument for questioning the bound state nature of this state,which also suggests that the large observed production rate could be consistent with a half-bound state.展开更多
We calculate the D s 1 （2536） ^＋ decays into D＊K channels,including the decay D s 1 （2536） ＋ → D ＋ π-K ＋ through a virtual D＊0 in a constituent quark model.Widths and S/D amplitudes ratio are in agreement ...We calculate the D s 1 （2536） ^＋ decays into D＊K channels,including the decay D s 1 （2536） ＋ → D ＋ π-K ＋ through a virtual D＊0 in a constituent quark model.Widths and S/D amplitudes ratio are in agreement with the recent Belle and BABAR data,being the results sensitive to 1 P 1 and 3 P 1 mixture.展开更多
The constituent quark model is used to compute the ground and excited state masses of QQQ baryons containing either c or b quarks.The quark model parameters previously used to describe the properties of charmonium and...The constituent quark model is used to compute the ground and excited state masses of QQQ baryons containing either c or b quarks.The quark model parameters previously used to describe the properties of charmonium and bottomonium states were used in this analysis.The non-relativistic three-body bound state problem is solved by means of the Gaussian expansion method which provides sufficient accuracy and simplifies the subsequent evaluation of the matrix elements.Several low-lying states with quantum numbers J^P=1/2^±,3/2^±,5/2^±and 7/2^+are reported.We compare the results with those obtained by the other theoretical formalisms.There is a general agreement for the mass of the ground state in each sector of triply heavy baryons.However,the situation is more puzzling for the excited states,and appropriate comments about the most relevant features of our comparison are given.展开更多
We analyze the effects of hyperfine mixing in b → c semileptonic decays of doubly heavy baryons.We qualitatively confirm the results by W.Roberts and M.Pervin in Int.J.Mod.Phys.A,2009,24： 2401– 2413,finding that mi...We analyze the effects of hyperfine mixing in b → c semileptonic decays of doubly heavy baryons.We qualitatively confirm the results by W.Roberts and M.Pervin in Int.J.Mod.Phys.A,2009,24： 2401– 2413,finding that mixing has a great impact on those transitions.However,predictions without mixing differ by a factor of 2 and this discrepancy translates to the mixed case where large differences in decay widths are observed between the two calculations.展开更多
We study the semileptonic decays of the lowest-lying bc baryons to the lowest-lying cc baryons （Ξ （＊） bc → Ξ （＊） cc and Ω （ ＊） bc → Ω （＊） cc ）,in the limit m b,m c Λ QCD and close to the zero reco...We study the semileptonic decays of the lowest-lying bc baryons to the lowest-lying cc baryons （Ξ （＊） bc → Ξ （＊） cc and Ω （ ＊） bc → Ω （＊） cc ）,in the limit m b,m c Λ QCD and close to the zero recoil point.The separate heavy quark spin symmetries make it possible to describe all these decays using a single form factor.We also show how these constraints can be used to test the validity of different quark model calculations.bb to bc baryon decays are also discussed.展开更多
Using local central Yukawa-type Malfliet-Tjon interactions reproducing the low-energy parameters and phase shifts of the nn system, and the latest updates of the nΛ and ΛΛ Nijmegen ESC08c potentials, we study the p...Using local central Yukawa-type Malfliet-Tjon interactions reproducing the low-energy parameters and phase shifts of the nn system, and the latest updates of the nΛ and ΛΛ Nijmegen ESC08c potentials, we study the possible existence of a ^4 ΛΛn bound state. Our results indicate that the ^4 ΛΛn is unbound, being just above threshold.We discuss the role played by the -1S0 nn repulsive term of the Yukawa-type Malfliet-Tjon interaction.展开更多
基金Work partially financed by the Escuela Politécnica Nacional under projects PIS-22-04 and PIM 19-01EU Horizon 2020 research and innovation program,STRONG-2020 project,under grant no.824093+1 种基金Ministerio Español de Ciencia e Innovación under grant nos.PID2022-141910NB-I00 and PID2022-140440NB-C22Junta de Andalucía under contract no.PAIDI FQM-370。
文摘By using the ^(3)P_(0) pair creation model,we provide a detailed derivation of the transition matrix for a baryon decaying into a meson-baryon system.This analysis was successfully conducted for a meson in[J.Segovia,D.R.Entem,and F.Fernandez,Phys.Lett.B 715,322(2012),and we extend the same formalism to the baryon sector,focusing on the △(1232)→πN strong decay width because all hadrons involved in the reaction are very well established,the two hadrons in the final state are stable and require no further analysis,all quarks are light and thus equivalent,and the decay width of the process is relatively well measured.Utilizing a very common Rayleigh-Ritz variational method to solve the 2-and 3-body Schodinger bound-state equation in which the hadron's radial wave functions are expanded in terms of a Gaussian basis,we can relate the expression of the invariant matrix element with the mean-square radii of hadrons involved in the decay.We use their experimental measures in such a way that only the strength of the quark-antiquark pair creation from the vacuum is a free parameter.This is then taken from our previous study on strong decay widths in the meson sector[J.Segovia,D.R.Entem,and F.Fernandez,Phys.Lett.B 715,322(2012),and the obtained results are compatible with the experimental results for the calculated △(1232)→πN decay width.Despite requiring the calculation of additional baryon strong decays,a feasible avenue towards a unified description of both baryon and meson strong decay widths within a single constituent quark model framework may be attainable.Finally,this research has been developed to lay the foundation for a novel raft of applications to exotic hadrons,i.e.,the description of the baryon's coupling to meson-baryon thresholds,one of the mechanisms that is considered to be responsible for providing either a large renormalization to naive states or genuine dynamicallygenerated meson-baryon molecules.
基金partly supported by the Spanish Ministerio de Economía y Competitividad and European FEDER funds(FPA2016-77177-C2-2-P,FIS2017-85053-C2-1-P)and Junta de Andalucía(FQM-225)
文摘All existing experimental evidence for the bound state nature of X(3872)relies on observing its decay products,which are measured with a finite experimental mass resolution that is typically△m≥2 MeV,and much larger than its alleged binding energy,BX=0.00(18)MeV.On the other hand,we have found recently that there is a clear cancellation in the 1^++channel of the invariant DD^*mass around the threshold between continuum and the bound state.This is very much like a similar cancellation in the proton-neutron continuum with the deuteron in the 1^++channel.Based on comparative fits with a common Tsallis distribution of the experimental cross-sections for prompt production of deuterons and X(3872)in pp collisions with a finite pT,we find a strong argument for questioning the bound state nature of this state,which also suggests that the large observed production rate could be consistent with a half-bound state.
基金Supported by Ministerio de Ciencia y Tecnología(FPA2007-65748)Junta de Castilla y León(SA-106A07,GR12)+1 种基金European Community-Research Infrastructure Integrating Activity"Study of Strongly Interacting Matter"(HadronPhysics2 Grant no.227431)Spanish Ingenio-Consolider 2010 Program CPAN(CSD2007-00042)
文摘We calculate the D s 1 （2536） ^＋ decays into D＊K channels,including the decay D s 1 （2536） ＋ → D ＋ π-K ＋ through a virtual D＊0 in a constituent quark model.Widths and S/D amplitudes ratio are in agreement with the recent Belle and BABAR data,being the results sensitive to 1 P 1 and 3 P 1 mixture.
基金Supported by China Postdoctoral Science Foundation(2019M650617)National Natural Science Foundation of China(11535005,11775118)+2 种基金Spanish Ministerio de Economía,Industria y Competitividad under contracts no.FPA2017-86380-P and FPA2016-77177-C2-2-P.P.G.O.the financial support from Spanish MINECO’s Juan de la Cierva-Incorporación programmeGrant Agreement No.IJCI-2016-28525
文摘The constituent quark model is used to compute the ground and excited state masses of QQQ baryons containing either c or b quarks.The quark model parameters previously used to describe the properties of charmonium and bottomonium states were used in this analysis.The non-relativistic three-body bound state problem is solved by means of the Gaussian expansion method which provides sufficient accuracy and simplifies the subsequent evaluation of the matrix elements.Several low-lying states with quantum numbers J^P=1/2^±,3/2^±,5/2^±and 7/2^+are reported.We compare the results with those obtained by the other theoretical formalisms.There is a general agreement for the mass of the ground state in each sector of triply heavy baryons.However,the situation is more puzzling for the excited states,and appropriate comments about the most relevant features of our comparison are given.
基金Supported by DGI and FEDER funds,under contracts FIS2008-01143/FIS,FIS2006-03438,FPA2007-65748,CSD2007- 00042Junta de Castilla y León under contracts SA016A07 and GR12+2 种基金Generalitat Valenciana under contract PROM- ETEO/20090090the EU HadronPhysics2 project,grant agreement n.227431supported by PIE- CSIC 200850I238 during his stay at IFIC
文摘We analyze the effects of hyperfine mixing in b → c semileptonic decays of doubly heavy baryons.We qualitatively confirm the results by W.Roberts and M.Pervin in Int.J.Mod.Phys.A,2009,24： 2401– 2413,finding that mixing has a great impact on those transitions.However,predictions without mixing differ by a factor of 2 and this discrepancy translates to the mixed case where large differences in decay widths are observed between the two calculations.
基金Supported by DGI and FEDER funds (FIS2006-03438,FIS2008-01143/FIS)PIE-CSIC (200850I238)
文摘We study the semileptonic decays of the lowest-lying bc baryons to the lowest-lying cc baryons （Ξ （＊） bc → Ξ （＊） cc and Ω （ ＊） bc → Ω （＊） cc ）,in the limit m b,m c Λ QCD and close to the zero recoil point.The separate heavy quark spin symmetries make it possible to describe all these decays using a single form factor.We also show how these constraints can be used to test the validity of different quark model calculations.bb to bc baryon decays are also discussed.
基金Supported by COFAA-IPN(Mxico),Ministerio de Economía,Industria y Competitividad and EU FEDER(FPA2013-47443,FPA2015-69714-REDT,FPA2016-77177)Junta de Castilla y Len(SA041U16)Generalitat Valenciana Prometeo II/2014/066
文摘Using local central Yukawa-type Malfliet-Tjon interactions reproducing the low-energy parameters and phase shifts of the nn system, and the latest updates of the nΛ and ΛΛ Nijmegen ESC08c potentials, we study the possible existence of a ^4 ΛΛn bound state. Our results indicate that the ^4 ΛΛn is unbound, being just above threshold.We discuss the role played by the -1S0 nn repulsive term of the Yukawa-type Malfliet-Tjon interaction.
