World data ofJ/ψproduction consolidate nonrelativistic QCD factorization at next-to-leading order

Abstract

We calculate the cross sections of inclusive J/ψ production in photoproduction and two-photon scattering, involving both direct and resolved photons, and in e + e − annihilation at next-to-leading order (NLO) within the factorization formalism of nonrelativistic quantum chromodynamics (NRQCD), including the full relativistic corrections due to the intermediate 1 S J color-octet (CO) states. Exploiting also our previous results on hadroproduction, we perform a combined fit of the respective CO long-distance matrix elements (LDMEs) to all available highquality data of inclusive J/ψ production, from KEKB, LEP II, RHIC, HERA, the Tevatron, and the LHC, comprising a total of 194 data points from 26 data sets.

Probing quarkonium production mechanisms with jet substructure

“…of 4.42, 1 found in ref. [5] is higher than one would hope for, but not unexpected given large theoretical uncertainties.…”

“…3) where we have now specialized to the case of interest where the jet energy E is measured for cone size R. 5 Loosely speaking this function gives the probability of finding a quarkonium whose large momentum fraction, relative to the jet within which it is found, is z. It is possible and indeed likely that there are small invariant mass jets in the data.…”

“…Large logarithms in the J ij (E, R, z, µ) are minimized at the scale 2E tan(R/2)(1−z). Note 4 If there were a hierarchy then one would have to run these operators from the scale Q to the scale E. 5 In refs. [16][17][18][19][20][21] the error scales as Λ 2 QCD instead of m 2 ψ .…”

“…NRQCD predictions at NLO in the coupling have been compared to the world data on J/ψ production in refs. [5,6]. The χ 2 /d.o.f.…”

“…The LDME of refs. [5,6] have again been used to set the normalization of the curves. In order to the make shapes of the curves more easily viewable, we have divided the 3 P (8)…”