Measurement of Jet Shapes in High-Q**2 Deep Inelastic Scattering at HERA

TL;DR

This paper measures jet shapes in high-Q^2 deep inelastic scattering at HERA, revealing that jet structure depends on energy but is similar across different scattering processes, indicating universal QCD radiation patterns.

Contribution

It provides the first detailed comparison of jet shapes in DIS with those in e+e- and pbarp collisions, highlighting the universality of quark-initiated jet radiation.

Findings

Jets become narrower with increasing E_T

Jet shapes in DIS are similar to e+e- interactions

Jets in DIS are narrower than in pbarp collisions

Abstract

The shapes of jets with transverse energies, E_T(jet), up to 45 GeV produced in neutral- and charged-current deep inelastic e+p scattering (DIS) at Q**2 > 100 GeV**2 have been measured with the ZEUS detector at HERA. Jets are identified using a cone algorithm in the eta-phi plane with a cone radius of one unit. The jets become narrower as E_T(jet) increases. The jet shapes in neutral- and charged-current DIS are found to be very similar. The jets in neutral-current DIS are narrower than those in resolved processes in photoproduction and closer to those in direct-photon processes for the same ranges in E_T(jet) and jet pseudorapidity. The jet shapes in DIS are observed to be similar to those in e+e- interactions and narrower than those in pbarp collisions for comparable E_T(jet). Since the jets in e+e- interactions and e+p DIS are predominantly quark initiated in both cases, the similarity in the jet shapes indicates that the pattern of QCD radiation within a quark jet is to a large extent independent of the hard scattering process in these reactions.