It is common lore that Parton Distribution Functions (PDFs) in the MS factorization scheme can become negative beyond leading order due to the collinear subtraction which is needed in order to define partonic cross sections. We show that this is in fact not the case and next-to-leading order (NLO) MS PDFs are actually positive in the perturbative regime. In order to prove this, we modify the subtraction prescription, and perform the collinear subtraction in such a way that partonic cross sections remain positive. This defines a factorization scheme in which PDFs are positive. We then show that positivity of the PDFs is preserved when transforming from this scheme to MS, provided only the strong coupling is in the perturbative regime, such that the NLO scheme change is smaller than the LO term.

Can MS parton distributions be negative? [Can $$ overline{mathrm{MS}} $$ parton distributions be negative?] / A. Candido, S. Forte, F. Hekhorn. - In: JOURNAL OF HIGH ENERGY PHYSICS. - ISSN 1029-8479. - 2020:11(2020 Nov 24). [10.1007/JHEP11(2020)129]

Can MS parton distributions be negative? [Can $$ overline{mathrm{MS}} $$ parton distributions be negative?]

A. Candido
Primo
;
S. Forte
Secondo
;
F. Hekhorn
Ultimo
2020

Abstract

It is common lore that Parton Distribution Functions (PDFs) in the MS factorization scheme can become negative beyond leading order due to the collinear subtraction which is needed in order to define partonic cross sections. We show that this is in fact not the case and next-to-leading order (NLO) MS PDFs are actually positive in the perturbative regime. In order to prove this, we modify the subtraction prescription, and perform the collinear subtraction in such a way that partonic cross sections remain positive. This defines a factorization scheme in which PDFs are positive. We then show that positivity of the PDFs is preserved when transforming from this scheme to MS, provided only the strong coupling is in the perturbative regime, such that the NLO scheme change is smaller than the LO term.
Deep Inelastic Scattering (Phenomenology); QCD Phenomenology
Settore FIS/02 - Fisica Teorica, Modelli e Metodi Matematici
   Proton strucure for discovery at the Large Hadron Collider (NNNPDF)
   NNNPDF
   EUROPEAN COMMISSION
   H2020
   740006
24-nov-2020
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/794339
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