We explore the decay properties of the isovector and isoscalar 1^(-+)light hybrids,π_(1)andη_(1),in N_(f)=2 lattice QCD at a pion mass m_(π)≈417 MeV.The Mc Neile and Michael method is adopted to extract the effect...We explore the decay properties of the isovector and isoscalar 1^(-+)light hybrids,π_(1)andη_(1),in N_(f)=2 lattice QCD at a pion mass m_(π)≈417 MeV.The Mc Neile and Michael method is adopted to extract the effective couplings for individual decay modes,which are used to estimate the partial decay widths ofπ_(1)(1600)andη_(1)(1855)by assuming SU(3)symmetry.The partial decay widths ofπ_(1)(1600)are predicted to be(Γ_(b_(1)π),Γ_(f1(1285)π),Γ_(ρπ),Γ_(K*K))=(325±75,O(10),52±7,8.6±1.3)Me V,and the total width is estimated to be 396±90 Me V,considering only statistical errors.Ifη_(1)(1855)and the 4.4σsignal observed by BESIII(labeled asη_(1)(2200))are taken as the two mass eigenstates of the isoscalar 1^(-+)light hybrids in SU(3),then the dominant decay channel(s)ofη_(1)(1855)(η_(1)(2200))is K_(1)(1270)K(K_(1)(1270)K and K_(1)(1400)K) through the 1^(+(-))0^(-(+))mode.The vector-vector decay modes are also significant for the twoη_(1)states.Using the mixing angleα≈22.7°obtained from lattice QCD for the twoη_(1)states,the total widths are estimated to beΓ_(η1(1855))=282(85)MeV andΓ_(η1(2200))=455(143)MeV.The former is compatible with the experimental width ofη_(1)(1855).Although many systematic uncertainties are not well controlled,these results are qualitatively informative for the experimental search for light hybrids.展开更多
We calculate the form factor M(q^(2))for the Dalitz decay J/ψ→γ*(q^(2))η(N_(f)=1)with η(N_(f))being the SU(N_(f))flavor singlet pseudoscalar meson.The difference among the partial widths Г(J/ψ→γη(N_(f)))at d...We calculate the form factor M(q^(2))for the Dalitz decay J/ψ→γ*(q^(2))η(N_(f)=1)with η(N_(f))being the SU(N_(f))flavor singlet pseudoscalar meson.The difference among the partial widths Г(J/ψ→γη(N_(f)))at different N_(f) can be attributed in part to the N_(f) and quark mass dependences induced by the U_(A)(1)anomaly dominance.M(q^(2))in both N_(f)=1,2 is well described by the single pole model M(q^(2))=M(0)/(1-q^(2)/Λ^(2)).Combined with the known experimental results of the Dalitz decays J/ψ-Pe^(+)e^(−),the pseudoscalar mass mp dependence of the pole parameter A is approximated byΛ(m^(2)_(p))=Λ_(1)(1-m^(2)_(p)/Λ_(2))withΛ_(1)=2.65(5)GeV andΛ_(2)=2.90(35)GeV.These results provide inputs for future theoretical and experimental studies on the Dalitz decays J/ψ→Pe^(+)e^(−).展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.11935017,12293060,12293065,12293061,12205311,12070131001(CRC 110 by DFG and NNSFC))the National Key Research and Development Program of China(Grant No.2020YFA0406400)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB34030302)。
文摘We explore the decay properties of the isovector and isoscalar 1^(-+)light hybrids,π_(1)andη_(1),in N_(f)=2 lattice QCD at a pion mass m_(π)≈417 MeV.The Mc Neile and Michael method is adopted to extract the effective couplings for individual decay modes,which are used to estimate the partial decay widths ofπ_(1)(1600)andη_(1)(1855)by assuming SU(3)symmetry.The partial decay widths ofπ_(1)(1600)are predicted to be(Γ_(b_(1)π),Γ_(f1(1285)π),Γ_(ρπ),Γ_(K*K))=(325±75,O(10),52±7,8.6±1.3)Me V,and the total width is estimated to be 396±90 Me V,considering only statistical errors.Ifη_(1)(1855)and the 4.4σsignal observed by BESIII(labeled asη_(1)(2200))are taken as the two mass eigenstates of the isoscalar 1^(-+)light hybrids in SU(3),then the dominant decay channel(s)ofη_(1)(1855)(η_(1)(2200))is K_(1)(1270)K(K_(1)(1270)K and K_(1)(1400)K) through the 1^(+(-))0^(-(+))mode.The vector-vector decay modes are also significant for the twoη_(1)states.Using the mixing angleα≈22.7°obtained from lattice QCD for the twoη_(1)states,the total widths are estimated to beΓ_(η1(1855))=282(85)MeV andΓ_(η1(2200))=455(143)MeV.The former is compatible with the experimental width ofη_(1)(1855).Although many systematic uncertainties are not well controlled,these results are qualitatively informative for the experimental search for light hybrids.
基金Supported by the National Natural Science Foundation of China (11935017,12293060,12293065,12293061,12293062,12293063,12075253,12192264,12175063,12205311,12070131001 (CRC 110 by DFG and NNSFC))the National Key Research and Development Program of China (2020YFA0406400)the Strategic Priority Research Program of Chinese Academy of Sciences (XDB34030302).
文摘We calculate the form factor M(q^(2))for the Dalitz decay J/ψ→γ*(q^(2))η(N_(f)=1)with η(N_(f))being the SU(N_(f))flavor singlet pseudoscalar meson.The difference among the partial widths Г(J/ψ→γη(N_(f)))at different N_(f) can be attributed in part to the N_(f) and quark mass dependences induced by the U_(A)(1)anomaly dominance.M(q^(2))in both N_(f)=1,2 is well described by the single pole model M(q^(2))=M(0)/(1-q^(2)/Λ^(2)).Combined with the known experimental results of the Dalitz decays J/ψ-Pe^(+)e^(−),the pseudoscalar mass mp dependence of the pole parameter A is approximated byΛ(m^(2)_(p))=Λ_(1)(1-m^(2)_(p)/Λ_(2))withΛ_(1)=2.65(5)GeV andΛ_(2)=2.90(35)GeV.These results provide inputs for future theoretical and experimental studies on the Dalitz decays J/ψ→Pe^(+)e^(−).
