A search for resonance decays to antineutrino-jet in e^+p scattering at HERA

TL;DR

This study analyzed the antineutrino-jet mass spectrum in e^+p collisions at HERA, finding no evidence of narrow resonance decays, and set limits on possible leptoquark and squark production based on the data.

Contribution

First to set mass-dependent limits on scalar and vector resonant states in e^+p scattering using ZEUS data at HERA.

Findings

No significant resonance signals observed.

Limits placed on leptoquark and squark production.

Results constrain models with R-parity violation.

Abstract

A study of the antineutrino-jet mass spectrum in e^+p -> antineutrino+X events at center-of-mass energy 300 GeV has been performed with the ZEUS detector at HERA using an integrated luminosity of 47.7 pb^-1. The mass spectrum is in good agreement with that expected from Standard Model processes over the antineutrino -jet mass range studied. No significant excess attributable to the decay of a narrow resonance is observed. By using both e^+p -> e^+ X and e^+p -> antineutrino X data, mass-dependent limits are set on the s-channel production of scalar and vector resonant states. Couplings to first-generation quarks are considered and limits are presented as a function of the e^+q and antineutrino-q branching ratios. These limits are used to constrain the production of leptoquarks and R-parity violating squarks.