Search for QCD Instanton-Induced Processes in DIS at HERA

Apr 12, 2016, 2:25 PM
20m
SR1 (DESY Hamburg)

SR1

DESY Hamburg

QCD and Hadronic Final States WG2 QCD and Hadronic Final States

Speaker

Stanislav Mikocki (Institute of Nuclear Physics Polish Academy of Sciences)

Description

Signals of QCD instanton-induced processes are searched for in deep-inelastic scattering (DIS) at the electron-proton collider HERA in the kinematic region defined by the Bjorken-scaling variable x > 0.001, the inelasticity 0.2< y < 0.7 and the photon virtuality 150 < Q2 < 15000 GeV^2. The search is performed using H1 data corresponding to an integrated luminosity of 350 pb^-1. Several observables of the hadronic final state of the events are exploited to identify a potentially instanton-enriched domain. Two Monte Carlo models, RAPGAP and ARIADNE, are used to estimate the background from the standard DIS processes, and the instanton-induced scattering processes are modeled by the program QCDINS. In order to extract the expected signal a multivariate data analysis technique is used. Exclusion limits on instanton production are reported, excluding cross sections larger than 2 pb. Limits are also reported as a function of parameters used to regularize the perturbative instanton model.

Primary author

Presentation materials