axial-vector mesons
نویسندگان
چکیده
A previous model where the low-lying axial-vector mesons are dynamically generated, implementing unitarity in coupled channels in the vector-pseudoscalar (V P ) meson interaction, is applied to evaluate the decay widths of the a1(1260) and b1(1235) axial-vector mesons into πγ. Unlike the case of the a1, the b1 radiative decay is systematically underestimated at tree level. In this work we evaluate for the first time the loop contribution coming from an initial V P vertex. Despite the large superficial divergence of the loops, the convergence of the relevant loops can be established by using arguments of gauge invariance. The partial decay widths obtained agree very well with the experimental values within uncertainties, and show that the loop contribution is crucial in the b1 case and also important for the a1 case.
منابع مشابه
8 On the radiative decays of light vector and axial - vector mesons
We study the light vector and axial-vector mesons. According to the hadrogenesis conjecture the nature of the two types of states is distinct. The axial-vector mesons are generated dynamically by coupled-channel interactions based on the chiral Lagrangian written down in terms of the Goldstone bosons and the light vector mesons. We propose a novel counting scheme that arises if the chiral Lagra...
متن کاملOn the radiative decays of light vector and axial - vector mesons
We study the light vector and axial-vector mesons. According to the hadrogenesis conjecture the nature of the two types of states is distinct. The axial-vector mesons are generated dynamically by coupled-channel interactions based on the chiral Lagrangian written down in terms of the Goldstone bosons and the light vector mesons. We propose a novel counting scheme that arises if the chiral Lagra...
متن کاملNucleon spin and the mixing of axial vector mesons.
It is shown that the QCD anomaly may lead to an abnormal mixing behavior of the axial vector mesons similar to the pseudoscalar mesons. These mixing effects, involving a gluonic axial vector state, generate a non-vanishing strange quark component in the nucleon. They reduce the matrix element of the singlet axial vector in comparison to the value obtained in a na¨ıve quark model. The results ar...
متن کاملDecay of axial vector mesons into VP and P
We propose a formalism for the decay of the SU (3) nonets of the axial vector mesons of J P C = 1 +− , 1 ++ into a vector meson and a pseudoscalar which is based on a tensor formulation of the vector and axial vector fields. The formulation leads to a good reproduction of the different decay branching ratios and assuming vector meson dominance (VMD) it also leads to good results for the radiati...
متن کاملSymmetries for Vector and Axial - Vector Mesons ∗
We discuss the possible symmetries of the effective lagrangian describing interacting pseudoscalar-, vector-, and axial-vector mesons. Specific choices of the parameters give rise to an [SU(2) ⊗ SU(2)] symmetry. This symmetry can be obtained either á la Georgi, with all states in the spectrum remaining massless, or in a new realization, implying decoupling of the pseudoscalar bosons from degene...
متن کاملRadiative decay into γP of the low lying axial - vector mesons
We evaluate the radiative decay into a pseudoscalar meson and a photon of the whole set of the axial-vector mesons dynamically generated from the vectorpseudoscalar meson (V P ) interaction. We take into account tree level and loop diagrams coming from the axial-vector decay into a vector and a pseudoscalar meson. We find a large span for the values of the radiative widths of the different axia...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2008