2017/02/10 by Bernd A. Kniehl, Kniehl, Bernd A., Anatoly V. Kotikov +1
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #High Energy Physics - Phenomenology (hep-ph) #High Energy Physics - Theory (hep-th) #hep-ex #hep-ph #hep-th
paper · pdf · doi:10.48550/arxiv.1702.03193
8 pages, 2 figures
arxiv created 2017/02/10 · arxiv updated 2017/02/13
We recover in QCD an amazingly simple relationship between the anomalous dimensions, resummed through next-to-next-to-leading-logarithmic order, in the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi evolution equations for the first Mellin moments Dq,g(μ2) of the quark and gluon fragmentation functions, which correspond to the average hadron multiplicities in jets initiated by quarks and gluons, respectively. This relationship, which is independent of the number of quark flavors, dramatically improves previous treatments by allowing for an exact solution of the evolution equations. So far, such relationships have only been known from supersymmetric QCD, where CF/CA=1. This also allows us to extend our knowledge of the ratio Dg-(μ2)/Dq-(μ2) of the minus components by one order in √(αs). Exploiting available next-to-next-to-next-to-leading-order information on the ratio Dg+(μ2)/Dq+(μ2) of the dominant plus components, we fit the world data of Dq,g(μ2) for charged hadrons measured in e+e- annihilation to obtain αs(5)(MZ)=0.1205\genfrac0pt+0.016-0.0020.