2016/06/30 by Zhong-Bo Kang, Felix Ringer, Ivan Vitev · 1 citation
Physics and Astronomy · #hep-ph #hep-ex
paper · pdf · doi:10.1007/jhep10(2016)125
published as JHEP 10 (2016) 125 · 35 pages, 11 figures, published version at JHEP
arxiv created 2016/10/27 · arxiv updated 2016/10/28
We introduce a new kind of jet function: the semi-inclusive jet function Ji(z, ωJ, μ), which describes how a parton i is transformed into a jet with a jet radius R and energy fraction z = ωJ/ω, with ωJ and ω being the large light-cone momentum component of the jet and the corresponding parton i that initiates the jet, respectively. Within the framework of Soft Collinear Effective Theory (SCET) we calculate both Jq(z, ωJ, μ) and Jg(z, ωJ, μ) to the next-to-leading order (NLO) for cone and anti-k\rm T algorithms. We demonstrate that the renormalization group (RG) equations for Ji(z, ωJ, μ) follow exactly the usual DGLAP evolution, which can be used to perform the ln R resummation for \it inclusive jet cross sections with a small jet radius R. We clarify the difference between our RG equations for Ji(z, ωJ, μ) and those for the so-called unmeasured jet functions Ji(ωJ, μ), widely used in SCET for \it exclusive jet production. Finally, we present applications of the new semi-inclusive jet functions to inclusive jet production in e+e- and pp collisions. We demonstrate that single inclusive jet production in these collisions shares the same short-distance hard functions as single inclusive hadron production, with only the fragmentation functions Dih(z, μ) replaced by Ji(z, ωJ, μ). This can facilitate more efficient higher-order analytical computations of jet cross sections. We further match our ln R resummation at both LLR and NLLR to fixed NLO results and present the phenomenological implications for single inclusive jet production at the LHC.