Study of final-state radiation in decays ofZbosons produced inppcollisions at 7 TeV

Abstract

The differential cross sections for the production of photons in Z → μ þ μ − γ decays are presented as a function of the transverse energy of the photon and its separation from the nearest muon. The data for these measurements are collected with the CMS detector and correspond to an integrated luminosity of 4.7 fb −1 of pp collisions at ffiffi ffi s p ¼ 7 TeV delivered by the CERN LHC. The cross sections are compared to simulations with POWHEG and PYTHIA, where PYTHIA is used to simulate parton showers and final-state photons. These simulations match the data to better than 5%.

Dark forces coupled to nonconserved currents

“…While these limits (from LEP) are not particularly stringent, we expect that the LHC has the capacity to significantly improve them. As illustrated by searches such as [35,36], it is likely that leptonic Z → γ(X → l + l − ) decays could be probed down to O(10 −5 ) branching ratios or better.…”

Conformal barrier and hidden local symmetry constraints: Walking technirhos in LHC diboson channels

“…The LHC limits obtained from searches for W ′ /Z ′ candidates [17,[56][57][58][59][60][61][62][63][64][65][66] constrain the 2 TeV technirho couplings to fermions (F ρ ) and weak bosons (g ρππ ). We compute the partial decay rates and the DY cross sections by using the analytic formulae given in Appendix B.…”

Interpretations of the ATLAS diboson anomaly

“…We shall show that the W decay into W Z dominates if the mixing angle is larger than 10 −2 . Therefore, it can explain the excess in the W Z channel without violating the leptonic cross sections [3][4][5][6] and the dijet-mass search at the LHC [7,8].…”