Search for Higgs andZBoson Decays toϕγwith the ATLAS Detector

Abstract

A search for the decays of the Higgs and Z bosons to a ϕ meson and a photon is performed with a pp collision data sample corresponding to an integrated luminosity of 2.7 fb^{-1} collected at sqrt[s]=13 TeV with the ATLAS detector at the LHC. No significant excess of events is observed above the background, and 95% confidence level upper limits on the branching fractions of the Higgs and Z boson decays to ϕγ of 1.4×10^{-3} and 8.3×10^{-6}, respectively, are obtained.

Ultraperipheral nuclear interactions

“…Besides the electron-positron pairs considered theoretically in Refs [5,7] and observed, e.g., in Refs [35,36], other pairs of oppositely charged particles with even C-parity can be created in the two-photon collisions. For example, pairs of muons produced in ultraperipheral collisions are observed at LHC [37,38,39,40,41]. The light-by-light scattering described theoretically by the loop of charged particles is also detected at LHC [42,43,44].…”

“…Prediction of large cross sections of ultraperipheral heavy ion collisions stimulated their experimental studies at RHIC [35] and LHC [36,37,38,39,40,41]. There are special signatures of these processes.…”

“…Production of µ + µ − pairs in pp collisions was first observed in 1990 at CERN's Intersecting Storage Rings (ISR) [61]. However the detailed experimental studies [37,39,40,41] and comparison with theory [34,50,51] became possible only recently.…”

“…It helped to get more definite information on the parameter u(Z). The experimental results from pp collisions at 13 TeV [39] and PbPb collisions at 5.02 TeV per nucleon pair [40] were considered.…”

Search for non-standard and rare decays of the Higgs boson with the ATLAS detector

“…This Section describes the search for a Higgs boson decay to the exclusive final state φ γ, where the φ meson is reconstructed from the decay φ → K + K − [1]. The search is performed with a sample of pp collision data corresponding to an integrated luminosity of 2.7 fb −1 recorded at a center-of-mass energy of 13 TeV with the ATLAS detector [2].…”