α_{S}(K_{T}^{2}) versus α_{S}(K^{2}) in QCD jet development: Some quantitative remarks
Abstract
Properties of QCD jets for two proposed choices of the variable appearing in the QCD running coupling constant, α_{S}(K^{2}) or α_{S}(K_{T}^{2}) with K_{T}^{2}=z(1z)K^{2}, have been studied in detail by the use of Monte Carlo techniques. Contrary to expectations based on approximate analytic calculations it is found that when substituting K^{2} with K_{T}^{2} in α_{S} the growth with energy of the multiplicity of the quanta is not sensibly altered, and it is even slowed down for extreme values of the nonperturbative cutoff, which delimits the minimum virtual mass of the quanta. It appears, therefore, that the analysis of subleading effects may be totally misleading if phasespace constraints are not taken into account exactly, which is possible to do in Monte Carlo calculations.
 Publication:

Physics Letters B
 Pub Date:
 August 1981
 DOI:
 10.1016/03702693(81)900836
 Bibcode:
 1981PhLB..103..465O