Non-perturbative chiral approach to Kp --gamma Y reactions(15)

A recently developed nonperturbative chiral approach to describe the S=-1 meson-baryon reactions has been extended to investigate the near threshold $K^- p \to \gamma \Lambda, \gamma \Sigma^0$ reactions. With the parameters governed by chiral SU(3) symmetr

Hence,weobtainacontributionproportionaltothecuto momentumsquared,inde-pendentofenergyandwiththesamestructureasthecontacttermintheBornamplitude,whichgoesintorenormalizingthecontacttermandistakenintoaccountwhenusingthistermwiththephysicalelectromagneticcouplinge.

Thegeneralizationtoothertermsoftheelectromagneticamplitudeandhigherorderloopsproceedsanalogouslywiththeconclusionthatonlytheonshellpartofthestrongamplitudemustbeused.