SUSY-like relation of the splitting functions in evolution of gluon and quark jet multiplicities

Abstract

We show the new relationship [1] between the anomalous dimensions, resummed through next-to-next-to-leading-logarithmic order, in the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) evolution equations for the first Mellin moments D_{q,g}(mu2) of the quark and gluon fragmentation functions, which correspond to the average hadron multiplicities in jets initiated by quarks and gluons, respectively. So far, such relationships have only been known from supersymmetric (SUSY) QCD. Exploiting available next-to-next-to-next-to-leading-order (NNNLO) information on the ratio D_g^+(mu2)/D_q^+(mu2) of the dominant plus components, the fit of the world data of D_{q,g}(mu2) for charged hadrons measured in e+e- annihilation leads to alpha_s^{(5)}(MZ)=0.1205 + 0.0016 - 0.0020.

Comments: 7 pages, 2 figures, talk given at the XXth International Seminar on High Energy Physics (Quarks-2018), Valday, Russia, May 27 -- June 2, 2018. arXiv admin note: text overlap with arXiv:1712.06045