Measurement of the production cross section for Zγ→ννˉγ in pp collisions at √s= 7 TeV and limits on ZZγ and Zγγ triple gauge boson couplings

Abstract

A measurement of the Zγ→νν¯¯¯γ cross section in pp collisions at √s=7 TeV is presented, using data corresponding to an integrated luminosity of 5.0 fb−1 collected with the CMS detector. This measurement is based on the observation of events with an imbalance of transverse energy in excess of 130 GeV and a single photon in the absolute pseudorapidity range |η| < 1.4 with transverse energy above 145 GeV. The Zγ→νν¯¯¯γ production cross section is measured to be 21.1 ± 4.2 (stat.) ± 4.3 (syst.) ± 0.5 (lum.) fb, which agrees with the standard model prediction of 21.9 ± 1.1 fb. The results are combined with the CMS measurement of Zγ production in the ℓ + ℓ − γ final state (where ℓ is an electron or a muon) to yield the most stringent limits to date on triple gauge boson couplings: ∣∣hZ3∣∣<2.7×10−3, ∣∣hZ4∣∣<1.3×10−5 for ZZγ and ∣∣hγ3∣∣<2.9×10−3, ∣∣hγ4∣∣<1.5×10−5 for Zγγ couplings.