As it is well known, large threshold logarithmic contributions can be resummed in the form factors within a fixed order approximation. Such form factors, however, are divergent at large x, as a consequence of the QCD coupling hitting the Landau pole in the resumming procedure. A possible solution is presented here, and it requires using an effective coupling which takes into account additional-usually neglected-absorptive physical effects; as a consequence, the theory becomes completely predictive with regular form factors at large x. These results are pertinent to a wide class of phenomenological applications, and in particular are of interest for processes at the B meson mass scale.
THRESHOLD RESUMMING WITH TIME-LIKE PRESCRIPTION / Ricciardi, Giulia. - In: INTERNATIONAL JOURNAL OF MODERN PHYSICS A. - ISSN 0217-751X. - 20:16(2005), pp. 3729-3731. [10.1142/S0217751X05027448]
THRESHOLD RESUMMING WITH TIME-LIKE PRESCRIPTION
RICCIARDI, GIULIA
2005
Abstract
As it is well known, large threshold logarithmic contributions can be resummed in the form factors within a fixed order approximation. Such form factors, however, are divergent at large x, as a consequence of the QCD coupling hitting the Landau pole in the resumming procedure. A possible solution is presented here, and it requires using an effective coupling which takes into account additional-usually neglected-absorptive physical effects; as a consequence, the theory becomes completely predictive with regular form factors at large x. These results are pertinent to a wide class of phenomenological applications, and in particular are of interest for processes at the B meson mass scale.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.