Search for a scalar or vector particle decaying into Zgamma in ppbar collisions at sqrt(s) = 1.96 TeV

TL;DR

This paper reports a search for new narrow scalar or vector particles decaying into Zgamma in proton-antiproton collisions at 1.96 TeV, setting upper limits on production cross sections across various masses.

Contribution

It provides the first limits on Zgamma decays of scalar and vector resonances at Tevatron energies, using data from the D0 detector.

Findings

No significant excess observed over standard model predictions.

Set 95% CL upper limits on cross section times branching ratio for different resonance masses.

Limits range from 0.19 to 2.5 pb depending on the resonance mass.

Abstract

We present a search for a narrow scalar or vector resonance decaying into Zgamma with a subsequent Z decay into a pair of electrons or muons. The data for this search were collected with the D0 detector at the Fermilab Tevatron ppbar collider at a center of mass energy sqrt(s) = 1.96 TeV. Using 1.1 (1.0) fb-1 of data, we observe 49 (50) candidate events in the electron (muon) channel, in good agreement with the standard model prediction. From the combination of both channels, we derive 95% C.L. upper limits on the cross section times branching fraction (sigma x B) into Zgamma. These limits range from 0.19 (0.20) pb for a scalar (vector) resonance mass of 600 GeV/c^2 to 2.5 (3.1) pb for a mass of 140 GeV/c^2.