Mixing and Decay Constants of Pseudoscalar Mesons(3)
发布时间:2021-06-05
发布时间:2021-06-05
We propose a new eta-eta' mixing scheme where we start from the quark flavor basis and assume that the decay constants in that basis follow the pattern of particle state mixing. On exploiting the divergences of the axial vector currents - which embody the
Transformingthenon-strangeandstrange
axial-vector
currentsintooctetandsingletcurrents,onecanalsoconnectthedecayconstantsde nedinEq.(1.1)tofqandfs
81 fηfη=U(φ)FU (θideal)(2.4)81fη′fη′
withtheresult
f8=
f1=
andthus 2fs/fq),2fq/fs)
√(2.5)tan(θ1 θ8)=
q-s
4π .GG(2.7)
itsdual;midenotethecurrentquarkmasses.Thevacuum–mesonGdenotesthegluon eldstrengthtensorandG
transitionmatrixelementsoftheaxialvectorcurrentdivergencesaregivenbytheproductofthesquareofthemeson2mass,MP,andtheappropriatedecayconstant.Forinstance,
s2s 0| µJµ5|η =Mηfη.(2.8)
Themassfactors,whichnecessarilyappearquadraticallyhere,canbeconsideredastheelementsoftheparticlemassmatrix 2 M0ηM2=.(2.9)20Mη′
iWiththehelpofEq.(2.3)thematrixelementsof µJµ5(i=q,s)canthenbeidenti edasthoseofthematrixproduct
M2U(φ)F.Transformingittothequark avorbasisandsolvingforthemassmatrix
2M2qs=U(φ)MU(φ),(2.10)
oneeasily nds
M2qs= m2qq+
2√fq 0|4παsfs |ηs GG 0|1αsm2ss+4π |ηs GG(2.11)
whereweusetheabbreviations
√m2qq=fq¯iγ5d|ηq ; 0|muu¯iγ5u+mddm2ss=2
2 0|αs 0|αsfs
.(2.13)