Improved dispersion relations for γ γ → π0 π0

En:

Phys Lett Sect B Nucl Elem Part High-Energy Phys 2008;659(1-2):201-208

Fecha:

2008

Formato:

application/pdf

Tipo de documento:

info:eu-repo/semantics/article
info:ar-repo/semantics/artículo
info:eu-repo/semantics/publishedVersion

Descripción:

We perform a dispersive theoretical study of the reaction γ γ → π0 π0 emphasizing the low energy region. The large source of theoretical uncertainty to calculate the γ γ → π0 π0 total cross section for sqrt(s) ≳ 0.5   GeV within the dispersive approach is removed. This is accomplished by taking one more subtraction in the dispersion relations, where the extra subtraction constant is fixed by considering new low energy constraints, one of them further refined by taking into consideration the f0 (980) region. This allows us to make sharper predictions for the cross section for sqrt(s) ≲ 0.8   GeV, below the onset of D-wave contributions. In this way, were new more precise data on γ γ → π0 π0 available one might then distinguish between different parameterizations of the ππ isoscalar S-wave. We also elaborate on the width of the σ resonance to γγ and provide new values. © 2007 Elsevier B.V. All rights reserved.

Identificador(es):

http://hdl.handle.net/20.500.12110/paper_03702693_v659_n1-2_p201_Oller

Derechos:

info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by/2.5/ar