TY - JOUR
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 -