NLL+NNLO predictions for jet-veto efficiencies in Higgs-boson and Drell-Yan production

Abstract

Using the technology of the caesar approach to resummation, we examine the jet-veto efficiency in Higgs-boson and Drell-Yan production at hadron colliders and show that at next-to-leading logarithmic (NLL) accuracy the resummation reduces to just a Sudakov form factor. Matching with NNLO calculations results in stable predictions for the case of Drell-Yan production, but reveals substantial uncertainties in gluon-fusion Higgs production, connected in part with the poor behaviour of the perturbative series for the total cross section. We compare our results to those from powheg with and without reweighting by hqt, as used experimentally, and observe acceptable agreement. In an appendix we derive the part of the NNLL resummation corrections associated with the radius dependence of the jet algorithm.

Jet veto clustering logarithms beyond leading order

“…In this case it is helpful to isolate clustering effects, and hence the R-dependence, into the ∆σ clustering correction. 3 Since the O(α s ) clustering correction vanishes, ∆σ (1) (p cut T ) = 0, the known O(α 2 s ) clustering effects are a LO quantity. This implies that ∆σ (3) (p cut T ), which contains the complete C 3 (R), could be determined from existing H + 2-jet NLO codes.…”

“…At O(α 2 s ), the leading clustering term has the coefficient [3] C ( For p cut T ∈ [25,30] GeV and R ∈ [0.4, 0.5], this term makes a contribution to U (2) clus which increases the cross section by an amount between 9% and 15%, which is on par with, or larger than, the theoretical uncertainties on the most recent predictions! Clearly the higher order terms are important to not only provide precise predictions, but to understand the uncertainty associated to these clustering effects.…”

“…Exclusive jet cross sections, such as the H + 0-jet cross section in which there are no jets with p T > p cut T , play a key role in channels where the Higgs cannot be reconstructed and jet binning is an effective discriminant between various Standard Model backgrounds. The uncertainty in theoretical predictions of these exclusive jet cross sections can be substantial, and accurately predicting these cross sections and providing robust estimates of their uncertainty is the focus of considerable effort [1][2][3][4][5][6][7][8][9][10][11][12]. A good example is the H → W W * → + − νν channel, where a fixed order analysis of the exclusive 0-jet and 1-jet cross sections have theoretical uncertainties of O(17%) and O(30%) respectively and dominate the systematic uncertainties in the measurement [13,14].…”

“…The clustering effects have two types of terms: those proportional to logarithms of m H /p cut T ("single logarithmic terms") and terms independent of p cut T ("finite terms"). At O(α 2 s ) all of the clustering terms have been determined, and both single logarithmic and finite terms have contributions proportional to ln R [3,5].…”

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].…”