Speaker
Description
Recently, performing a reanalysis of elastic $P$-wave $\pi\pi$ phase shifts and inelasticities [1], it is argued strongly that there existed an isovector vector meson with a mass around 1.26 GeV, that is $\rho(1250)$. Its existence has a long history and is still in a long-standing controversy both experimentally and theoretically, so that its entry to the PDG listings has not yet been accepted and the relevant observations are listed under the $\rho (1450)$[2]. In the conventional constituent quark potential models, it is difficult to make the predicted mass of the $2^3 S_1$ state smaller than that of the Godfrey and Isgur model [3], and therefore the nature of the $\rho (1250)$ state and its properties have not been clarified yet.
In this work we study strong decays with one pion emission of the excited $\rho$ meson states in a framework of the covariant representation scheme for hadrons. In this scheme negative energy components of constituent quarks can be incorporated into the covariant spin wave functions of $q\bar{q}$ states. We discuss a possibility of understanding the properties of the excited $\rho$ mesons, including the controversial $\rho(1250)$, by considering a mixing with states containing negative energy components.
References
[1] N. Hammoud, R. Kaminski, V. Nazari, and G. Rupp, Phys. Rev. D102, 054029 (2020).
[2] R.L. Workman et al. (Particle Data Group), Prog. Theor. Exp. Phys. 2022, 083C01 (2022).
[3] S. Godfrey and N. Isgur, Phys. Rev. D32, 189 (1985).
