A search for forbidden and exotic Z boson decays in the diphoton mass spectrum is presented for the first time in hadron collisions, based on data corresponding to 10.0 fb(-1) of integrated luminosity from proton-antiproton collisions at root s = 1.96 TeV collected by the CDF experiment. No evidence of signal is observed, and 95% credibility level Bayesian upper limits are set on the branching ratios of decays of the Z boson to a photon and neutral pion (which is detected as a photon), a pair of photons, and a pair of neutral pions. The observed branching ratio limits are 2.01 x 10(-5) for Z -> pi(0)gamma, 1.46 x 10(-5) for Z -> gamma gamma, and 1.52 x 10(-5) for Z -> pi(0)pi(0). The Z -> pi(0)gamma and Z -> gamma gamma limits improve the most stringent results from other experiments by factors of 2.6 and 3.6, respectively. The Z -> pi(0)pi(0) branching ratio limit is the first experimental result on this decay.
|Titolo:||First Search for Exotic Z Boson Decays into Photons and Neutral Pions in Hadron Collisions|
|Data di pubblicazione:||2014|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1103/PhysRevLett.112.111803|
|Appare nelle tipologie:||1.1 Articolo in rivista|