Comprehending isospin breaking effects of X(3872) in a Friedrichs-model-like scheme

Additional Isospin-Breaking Effects in ǫ′/ǫ

Isospin-breaking effects, in particular those associated with electroweakpenguin contributions and π-η, η mixing, have long been known to affect the Standard Model prediction of ǫ/ǫ in a significant manner. We have found an heretofore unconsidered isospin-violating effect of importance; namely, the u-d quark mass difference can spawn |∆I| = 3/2 components in the matrix elements of the gluonic p...

Isospin Symmetry Breaking within the HLS Model : A Full ( ρ , ω , φ ) Mixing Scheme

We study the way isospin symmetry violation can be generated within the Hidden Local Symmetry (HLS) Model. We show that isospin symmetry breaking effects on pseudoscalar mesons naturally induces correspondingly effects within the physics of vector mesons, through kaon loops. In this way, one recovers all features traditionally expected from ρ−ω mixing and one finds support for the Orsay phase m...

Understanding X(3862), X(3872), and X(3930) in a Friedrichs-model-like scheme

We developed a Friedrichs-model-like scheme in studying the hadron resonance phenomenology and present that the hadron resonances might be regarded as the Gamow states produced by a Hamiltonian in which the bare discrete state is described by the result of usual quark potential model and the interaction part is described by the quark pair creation model. In an almost parameter-free calculation,...

Isospin Symmetry Breaking

Isospin symmetry breaking

We discuss the separation of isospin-symmetric and isospin-breaking contributions in the hadronic observables within the framework of QCD plus QED. Further, we briefly review some recent work on the low-energy hadron phenomenology, in which the isospin-breaking effect plays a prominent role.