Jet angularities in photoproduction at the Electron-Ion Collider

Abstract

We consider the one-parameter family of jet substructure observables known as angularities using the specific case of inclusive jets arising from photoproduction events at an Electron-Ion Collider (EIC). We perform numerical calculations at next-to-leading logarithmic accuracy within perturbative QCD and compare our results to PYTHIA 6 predictions. Overall, we find good agreement and conclude that jet substructure observables are feasible at the EIC despite the relatively low jet transverse momentum and particle multiplicities. We investigate the size of subleading power corrections relevant at low energies within the Monte Carlo setup. In order to establish the validity of the Monte Carlo tune, we also perform comparisons to jet shape data at HERA. We further discuss detector requirements necessary for angularity measurements at an EIC, focusing on hadron calorimeter energy and spatial resolutions. Possible applications of precision jet substructure measurements at the EIC include the tuning of Monte Carlo event generators, the extraction of nonperturbative parameters and studies of cold nuclear matter effects. * elke@bnl.gov

Recent progress in jet substructure calculations

“…Theoretical predictions are available in a variety of frameworks [37][38][39][40][41][42][43]. Calculations are also performed for related observables at lepton colliders [5,44,45] and in deep inelastic scattering [46,47]. A recent calculation is the one presented in [43], closely following the precise measurement prescription in [36] for the groomed and ungroomed angularities measured on the leading anti-k t jet in Z+jet production.…”

Diffractive dijet photoproduction at the EIC

“…Dijet photoproduction at the LHC might even provide novel constraints on nuclear PDFs [29] or first information on the yet unknown diffractive nuclear PDFs [28,30]. In the medium term, the recently approved electron-ion collider (EIC) at BNL [31] has the potential for detailed studies of jets in DIS [32][33][34][35][36][37][38] and photoproduction [39][40][41][42] in the clean environment of an electron-nucleus collider, which was planned for Run 3 at HERA, but never implemented.…”

Angularity in DIS at next-to-next-to-leading log accuracy

“…They were also extensively studied in DIS [28]. Improved theoretical predictions [29,30] and new predictions [31][32][33][34] for event shapes that JHEP11(2021)026…”

“…(1.1) because it is assumed that particles are already grouped into X by some algorithm and their rapidity in the region is positive.2 Here, the definition of DIS angularity includes both hemispheres of the event hence, is directly sensitive to initial state radiations in beam region as well as final-state radiations in jet region. Our observable and its factorization are distinguished from jet angularity[31], which is defined from jet constituents being sensitive to final state radiations while insensitive to initial state radiations upon neglecting corrections of jet radius and effect of non-global logarithms.…”