Measurement of the production cross section for $ \mathrm{Z}\gamma \to \nu \overline{\nu}\gamma $ in pp collisions at $ \sqrt{s} = 7 $ TeV and limits on ZZγ and Zγγ triple gauge boson couplings

Abstract

Abstract A measurement of the $ \mathrm{Z}\gamma \to \nu \overline{\nu}\gamma $ cross section in pp collisions at $ \sqrt{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 $ \mathrm{Z}\gamma \to \nu \overline{\nu}\gamma $ 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: $ \left| {h_3^Z} \right|<2.7\times {10^{-3 }} $ , $ \left| {h_4^Z} \right|<1.3\times {10^{-5 }} $ for ZZγ and $ \left| {h_3^{\gamma }} \right|<2.9\times {10^{-3 }} $ , $ \left| {h_4^{\gamma }} \right|<1.5\times {10^{-5 }} $ for Zγγ couplings.