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Meson-loop contributions to the rho-omega mass splitting & rho charge radius

M. A. Pichowsky·Sameer Walawalkar·Simon Capstick
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Abstract

Contributions of two-pseudoscalar and vector-pseudoscalar meson loops to the rho-omega mass splitting are evaluated in a covariant model based on studies of the Schwinger-Dyson equations of QCD. The role and importance of the different time orderings of the meson loops is analyzed and compared with those obtained within time-ordered perturbation theory. It is shown that each meson loop contributes less than 10% of the bare mass, and decreases as the masses of the intermediate mesons increase beyond approximately m_rho/2. A mass splitting of m_omega - m_rho ~= 25 MeV is obtained from the pi pi, K K(bar), omega pi, rho pi, omega eta, rho eta and K* K channels. The model is then used to determine the effect of the two-pion loop on the rho-meson electromagnetic form factor. It is shown that the inclusion of pion loops increases the rho-meson charge radius by 10%.

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M. A. Pichowsky, Sameer Walawalkar, Simon Capstick. 1999-04-29. Meson-loop contributions to the rho-omega mass splitting & rho charge radius. https://doi.org/10.1103/physrevd.60.054030

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