A search for the Zγ decay mode of the Higgs boson in pp collisions at √s=13 TeV with the ATLAS detector : Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

Collaboration, ATLAS and Barton, A.E. and Bertram, I.A. and Borissov, G. and Bouhova-Thacker, E.V. and Fox, H. and Henderson, R.C.W. and Jones, R.W.L. and Kartvelishvili, V. and Long, R.E. and Love, P.A. and Muenstermann, D. and Parker, A.J. and Sanderswood, Izaac and Smizanska, M. and Tee, A.S. and Walder, J. and Wharton, A.M. and Whitmore, B.W. and Yexley, Melissa (2020) A search for the Zγ decay mode of the Higgs boson in pp collisions at √s=13 TeV with the ATLAS detector : Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. Phys Lett Sect B Nucl Elem Part High-Energy Phys, 809: 135754. ISSN 0370-2693

Abstract

A search for the Zγ decay of the Higgs boson, with Z boson decays into pairs of electrons or muons is presented. The analysis uses proton–proton collision data at √s=13 TeV corresponding to an integrated luminosity of 139 fb−1 recorded by the ATLAS detector at the Large Hadron Collider. The observed data are consistent with the expected background with a p-value of 1.3%. An upper limit at 95% confidence level on the production cross-section times the branching ratio for pp→H→Zγ is set at 3.6 times the Standard Model prediction while 2.6 times is expected in the presence of the Standard Model Higgs boson. The best-fit value for the signal yield normalised to the Standard Model prediction is 2.0−0.9+1.0 where the statistical component of the uncertainty is dominant.