We summarize and extend previous results on the comparison of threshold resummation, performed using soft-collinear effective theory (SCET) in the Becher-Neubert approach, to the standard perturbative QCD formalism based on factorization and resummation of Mellin moments of partonic cross sections. We show that the logarithmic accuracy of the SCET result can be extended by half a logarithmic order, thereby bringing it in full agreement with the standard QCD result if a suitable choice is made for the soft scale μs which characterizes the SCET result. We provide a master formula relating the two approaches for other scale choices. We then show that with the Becher-Neubert scale choice the Landau pole, which in the perturbative QCD approach is usually removed through power- or exponentially suppressed terms, in the SCET approach is removed by logarithmically subleading terms which break factorization. Such terms may become leading for generic choices of parton distributions, and are always leading when resummation is used far enough from the hadronic threshold. © 2013 Elsevier B.V.

The scale of soft resummation in SCET vs perturbative QCD / Marco, Bonvini; Stefano, Forte; Ghezzi, Margherita; Giovanni, Ridolfi. - In: NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS. - ISSN 0920-5632. - 241-242:(2013), pp. 121-126. [10.1016/j.nuclphysbps.2013.06.020]

The scale of soft resummation in SCET vs perturbative QCD

GHEZZI, MARGHERITA;
2013

Abstract

We summarize and extend previous results on the comparison of threshold resummation, performed using soft-collinear effective theory (SCET) in the Becher-Neubert approach, to the standard perturbative QCD formalism based on factorization and resummation of Mellin moments of partonic cross sections. We show that the logarithmic accuracy of the SCET result can be extended by half a logarithmic order, thereby bringing it in full agreement with the standard QCD result if a suitable choice is made for the soft scale μs which characterizes the SCET result. We provide a master formula relating the two approaches for other scale choices. We then show that with the Becher-Neubert scale choice the Landau pole, which in the perturbative QCD approach is usually removed through power- or exponentially suppressed terms, in the SCET approach is removed by logarithmically subleading terms which break factorization. Such terms may become leading for generic choices of parton distributions, and are always leading when resummation is used far enough from the hadronic threshold. © 2013 Elsevier B.V.
2013
qcd; resummation; soft-collinear effective theory; soft-gluon; threshold
04 Pubblicazione in atti di convegno::04c Atto di convegno in rivista
The scale of soft resummation in SCET vs perturbative QCD / Marco, Bonvini; Stefano, Forte; Ghezzi, Margherita; Giovanni, Ridolfi. - In: NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS. - ISSN 0920-5632. - 241-242:(2013), pp. 121-126. [10.1016/j.nuclphysbps.2013.06.020]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/541651
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