Finding the sigma pole by analytic extrapolation of {pi}{pi} scattering data

Journal Article · Sun Jun 01 04:00:00 EDT 2008 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.77.114019· OSTI ID:21205082

Caprini, Irinel ^[1]

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1. National Institute of Physics and Nuclear Engineering, POB MG 6, Bucharest, R-077125 (Romania)

I investigate the determination of the {sigma} pole from {pi}{pi} scattering data below the KK threshold, including the new precise results obtained from K{sub e4} decay by NA48/2 Collaboration. I discuss also the experimental status of the threshold parameters a{sub 0}{sup 0} and b{sub 0}{sup 0} and the phase shift {delta}{sub 0}{sup 0}. In order to reduce the theoretical bias, I use a large class of analytic parametrizations of the isoscalar S wave, based on expansions in powers of conformal variables. The {sigma} pole obtained with this method is consistent with the prediction based on ChPT and Roy equations. However, the theoretical uncertainties are now larger, reflecting the sensitivity of the pole position to the specific parametrizations valid in the physical region. I conclude that Roy equations offer the most precise method for the determination of the {sigma} pole from {pi}{pi} elastic scattering.

• OSTI ID: 21205082
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 11 Vol. 77; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
DECAY
ELASTIC SCATTERING
EQUATIONS
EXPANSION
EXTRAPOLATION
FORECASTING
PHASE SHIFT
PION-PION INTERACTIONS
S WAVES
SENSITIVITY