Minimal subtraction vs. physical factorisation schemes in small-x QCD

M. Ciafaloni; D. Colferai; G. P. Salam; A. M. Staśto

doi:10.1016/j.physletb.2006.03.014

Minimal subtraction vs. physical factorisation schemes in small-x QCD

M. Ciafaloni
, D. Colferai
, G. P. Salam
, A. M. Staśto

Physics

Research output: Contribution to journal › Article › peer-review

37 Scopus citations

Abstract

We investigate the relationship of "physical" parton densities defined by k-factorisation, to those in the minimal subtraction scheme, by comparing their small-x behaviour. We first summarize recent results on the above scheme change derived from the BFKL equation at NLx level, and we then propose a simple extension to the renormalisation-group-improved (RGI) equation. In this way we are able the examine the difference between resummed gluon distributions in the Q₀ and over(MS, -) schemes and also to show over(MS, -) scheme resummed results for P_{g g} and approximate ones for P_{q g}. We find that, due to the stability of the RGI approach, small-x resummation effects are not much affected by the scheme-change in the gluon channel, while they are relatively more important for the quark-gluon mixing.

Original language	English (US)
Pages (from-to)	320-329
Number of pages	10
Journal	Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Volume	635
Issue number	5-6
DOIs	https://doi.org/10.1016/j.physletb.2006.03.014
State	Published - Apr 20 2006

All Science Journal Classification (ASJC) codes

Nuclear and High Energy Physics

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10.1016/j.physletb.2006.03.014

Cite this

@article{f8952696758a441a9bb47731d989053e,

title = "Minimal subtraction vs. physical factorisation schemes in small-x QCD",

abstract = "We investigate the relationship of {"}physical{"} parton densities defined by k-factorisation, to those in the minimal subtraction scheme, by comparing their small-x behaviour. We first summarize recent results on the above scheme change derived from the BFKL equation at NLx level, and we then propose a simple extension to the renormalisation-group-improved (RGI) equation. In this way we are able the examine the difference between resummed gluon distributions in the Q0 and over(MS, -) schemes and also to show over(MS, -) scheme resummed results for Pg g and approximate ones for Pq g. We find that, due to the stability of the RGI approach, small-x resummation effects are not much affected by the scheme-change in the gluon channel, while they are relatively more important for the quark-gluon mixing.",

author = "M. Ciafaloni and D. Colferai and Salam, \{G. P.\} and Sta{\'s}to, \{A. M.\}",

note = "Funding Information: We thank John Collins for a question about positivity of the gluon in the MS ‾ scheme which motivated us, in part, to push forwards with these investigations. This research has been partially supported by the Polish Committee for Scientific Research, KBN Grant No. 1 P03B 028 28, by the US Department of Energy, Contract No. DE-AC02-98CH10886 and by MIUR (Italy).",

year = "2006",

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doi = "10.1016/j.physletb.2006.03.014",

language = "English (US)",

volume = "635",

pages = "320--329",

journal = "Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics",

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T1 - Minimal subtraction vs. physical factorisation schemes in small-x QCD

AU - Ciafaloni, M.

AU - Colferai, D.

AU - Salam, G. P.

AU - Staśto, A. M.

N1 - Funding Information: We thank John Collins for a question about positivity of the gluon in the MS ‾ scheme which motivated us, in part, to push forwards with these investigations. This research has been partially supported by the Polish Committee for Scientific Research, KBN Grant No. 1 P03B 028 28, by the US Department of Energy, Contract No. DE-AC02-98CH10886 and by MIUR (Italy).

PY - 2006/4/20

Y1 - 2006/4/20

N2 - We investigate the relationship of "physical" parton densities defined by k-factorisation, to those in the minimal subtraction scheme, by comparing their small-x behaviour. We first summarize recent results on the above scheme change derived from the BFKL equation at NLx level, and we then propose a simple extension to the renormalisation-group-improved (RGI) equation. In this way we are able the examine the difference between resummed gluon distributions in the Q0 and over(MS, -) schemes and also to show over(MS, -) scheme resummed results for Pg g and approximate ones for Pq g. We find that, due to the stability of the RGI approach, small-x resummation effects are not much affected by the scheme-change in the gluon channel, while they are relatively more important for the quark-gluon mixing.

AB - We investigate the relationship of "physical" parton densities defined by k-factorisation, to those in the minimal subtraction scheme, by comparing their small-x behaviour. We first summarize recent results on the above scheme change derived from the BFKL equation at NLx level, and we then propose a simple extension to the renormalisation-group-improved (RGI) equation. In this way we are able the examine the difference between resummed gluon distributions in the Q0 and over(MS, -) schemes and also to show over(MS, -) scheme resummed results for Pg g and approximate ones for Pq g. We find that, due to the stability of the RGI approach, small-x resummation effects are not much affected by the scheme-change in the gluon channel, while they are relatively more important for the quark-gluon mixing.

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U2 - 10.1016/j.physletb.2006.03.014

DO - 10.1016/j.physletb.2006.03.014

M3 - Article

AN - SCOPUS:33645879229

SN - 0370-2693

VL - 635

SP - 320

EP - 329

JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

IS - 5-6

ER -

Minimal subtraction vs. physical factorisation schemes in small-x QCD

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