Alternative calculation of the physical mass of the p-meson

We have derived an expression for the physical mass and width of the ρ-meson in vacuum from its spectral function, calculated in the vector meson dominance model when a ρ 0 meson couples to two virtual pions π +–π −. The propagator is computed after evaluating the ρ-meson self-energy. The real part...

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Detalles Bibliográficos
Autores principales: Morones Ramírez, Rubén, Mejía Rosales, Sergio
Formato: Artículo
Lenguaje:inglés
Publicado: World Scientific Publishing Company 2005
Materias:
Acceso en línea:http://eprints.uanl.mx/8962/1/ALTERNATIVE%20CALCULATION%20OF%20THE%20PHYSICAL%20MASS%20OF.pdf
Descripción
Sumario:We have derived an expression for the physical mass and width of the ρ-meson in vacuum from its spectral function, calculated in the vector meson dominance model when a ρ 0 meson couples to two virtual pions π +–π −. The propagator is computed after evaluating the ρ-meson self-energy. The real part of the ρ-meson self-energy is given by a divergent integral and needs to be regularized; the regularization is done by using a double subtracted dispersion relation. The result leads to a closed analytical expression which allow us to evaluate the spectral function in a closed way. The physical mass, defined as the magnitude of the four-momentum |k| for which the spectral function S(k 2 ) attains its maximum value, is obtained, and it gives a value of 770 MeV, which is in total agreement with the reported experimental value of the ρ-meson mass