Universidad Complutense de Madrid
E-Prints Complutense

Chiral extrapolation of light resonances from one and two-loop unitarized chiral perturbation theory versus lattice results



Downloads per month over past year

Peláez Sagredo, José Ramón and Rios, G. (2010) Chiral extrapolation of light resonances from one and two-loop unitarized chiral perturbation theory versus lattice results. Physical review D, 82 (11). ISSN 1550-7998

[thumbnail of pelaezsagredo22libre.pdf]

Official URL: http://dx.doi.org/10.1103/PhysRevD.82.114002


We study the pion mass dependence of the ρ(770) and f_0(600) masses and widths from one and two-loop unitarized chiral perturbation theory ( ChPT). We show the consistency of one-loop calculations with lattice results for the M_ρ, f_π and the isospin-2 scattering length a-20. Then, we develop and apply the modified inverse amplitude method formalism for two-loop ChPT. In contrast to the f_0(600), the ρ(770) is rather sensitive to the two-loop ChPT parameters-our main source of systematic uncertainty. We thus provide two-loop unitarized fits constrained by lattice information on M_ρ, f_π, by the q q̅ leading 1/N_c behavior of the ρ and by existing estimates of low-energy constants. These fits yield relatively stable predictions up to m_π ̴̲ 300-350 MeV for the rho coupling and width as well as for all the f_0(600) parameters. We confirm, to two loops, the weak m_π dependence of the rho coupling and the Kawarabayashi-Suzuki-Riazuddin-Fayyazuddin relation, and the existence of two virtual f_0(600) poles for sufficiently high m_π. At two loops one of these poles becomes a bound state when m_π is somewhat larger than 300 MeV.

Item Type:Article
Additional Information:

©2010 The American Physical Society.
We thank C. Hanhart for useful discussions. Work partially supported by Spanish Ministerio de Educación y Ciencia research Contract Nos. FPA2007-29115-E, FPA2008-00592, and FIS2006- 03438, U. Complutense/ Banco Santander Grant Nos. PR34/07-15875-BSCH and UCM-BSCH GR58/08 910309. We acknowledge the support of the European Community-Research Infrastructure Integrating Activity Study of Strongly Interacting Matter (acronym HadronPhysics2, Grant Agreement No. 227431) under the Seventh Framework Programme of EU.

Uncontrolled Keywords:Pi-pi scattering; Scalar mesons; Gev-c; Dispersion-relations; High statistics; Form-factors; Low-energy; One-loop; Sigma; Lagrangians
Subjects:Sciences > Physics > Physics-Mathematical models
Sciences > Physics > Mathematical physics
ID Code:35071
Deposited On:19 Jan 2016 17:30
Last Modified:10 Dec 2018 15:09

Origin of downloads

Repository Staff Only: item control page