Study of the Zgamma production in gamma+MET final state at sqrt{s} = 7 TeV

The first measurement of the ${\rm Z}\gamma\to\nu\bar{\nu}\gamma$ cross section in pp collisions at $\sqrt{s} = 7$~TeV is presented, using data corresponding to an integrated luminosity of 5 fb$^{-1}$ collected with the CMS detector. The measurement is based on the observation of events with an imbalance of the transverse energy in excess of 130 GeV and a single photon candidate in the absolute pseudorapidity range $|\eta| < 1.4$ and with the transverse energy above 145 GeV. The Z$\gamma\to\nu\bar{\nu}\gamma$ production cross section is measured to be $21.3 \pm 4.2 ({\rm stat.}) \pm 4.3 ({\rm syst.}) \pm 0.5 ({\rm lumi.})$ fb, which is in good agreement with the theoretical prediction of $21.9 \pm 1.1$ fb in the standard model. In addition, the most stringent limits to date are established on the anomalous ${\rm Z}{\rm Z}\gamma$ and ${\rm Z}\gamma\gamma$ trilinear gauge boson couplings.