Excited scalar and pseudoscalar mesons in the extended linear sigma model

Abstract

We present an in-depth study of masses and decays of excited scalar and pseudoscalar q¯ q states in the Extended Linear Sigma Model (eLSM). The model also contains ground-state scalar, pseudoscalar, vector and axial-vector mesons. The main objective is to study the consequences of the hypothesis that the f0(1790) resonance, observed a decade ago by the BES Collaboration and recently by LHCb, represents an excited scalar quarkonium. In addition we also analyse the possibility that the new a0(1950) resonance, observed recently by BABAR, may also be an excited scalar state. Both hypotheses receive justification in our approach although there appears to be some tension between the simultaneous interpretation of f0(1790) /a0(1950) and pseudoscalar mesons η(1295) , π(1300) , η(1440) and K(1460) as excited q¯ q states.