RT Journal Article
T1 Chiral extrapolation of light resonances from one and two-loop unitarized chiral perturbation theory versus lattice results
A1 Peláez Sagredo, José Ramón
A1 Rios, G.
AB 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.
PB Amer Physical Soc
SN 1550-7998
YR 2010
FD 2010-11-01
LK https://hdl.handle.net/20.500.14352/44838
UL https://hdl.handle.net/20.500.14352/44838
LA eng
NO ©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.
NO Unión Europea. FP7
NO Ministerio de Educacion y Ciencia
NO Universidad Complutense/Banco Santander
DS Docta Complutense
RD 9 abr 2025