The resummation of inter-jet energy flow for gaps-between-jets processes at HERA

Abstract

We calculate resummed perturbative predictions for gaps-between-jets processes and compare to HERA data. Our calculation of this non-global observable needs to include the effects of primary gluon emission (global logarithms) and secondary gluon emission (non-global logarithms) to be correct at the leading logarithm (LL) level. We include primary emission by calculating anomalous dimension matrices for the geometry of the specific event definitions and estimate the effect of non-global logarithms in the large N c limit. The resulting predictions for energy flow observables are consistent with experimental data.

Probing the gauge content of heavy resonances with soft radiation

“…(11), and is always larger than 1 for massive partons and equal to one for the massless case. We will see that all the results we derive here go back to the previous calculation for massless dijet events, ¼ 1 [10,12]. For complete integrations over the rapidity gap geometry, it is convenient to integrate ij over an azimuthal angle first.…”

“…(29) to crosscheck these results with the previous calculation for massless dijet events, and find [12] ð1Þ S ð12Þ ¼ Y À i; …”

Soft evolution of multi-jet final states

“…Very high logarithmic accuracy (N 3 LL) was achieved using Soft Collinear Effective Theory (SCET) for particular event shapes in e + e − collisions [51,52]. Inter-jet radiation and in particular its response to the presence of a jet veto has also received a lot of attention both from the theoretical [53][54][55][56][57][58][59] and experimental [60][61][62][63] communities, primarily in the context of Higgs-boson studies [64][65][66][67][68][69][70]. All-order analytical calculations have been performed recently for an increasing number of jet-substructure observables, including jet masses [71][72][73][74], other jet shapes [75][76][77][78][79], sub-jet multiplicity [80] and grooming algorithms [81][82][83].…”

The dijet cross section with a jet veto

“…Thus, the gap region is not just a rectangle in the (η, φ) plane and we have to integrate around the two semi-circular boundaries of the leading jets. Analytical expressions can still be obtained as a power series in R [39]. Here instead we decide to keep the full R dependence and perform the integrals numerically when we cannot find simple analytical results.…”