Search for Higgs and $Z$ Boson Decays to $J/\psi\gamma$ and $\Upsilon(nS)\gamma$ with the ATLAS Detector

G. Aad , S. Albrand (1) , J. Brown (1) , J. Collot (1) , S. Crépé-Renaudin (1) , P.A. Delsart (1) , C. Gabaldon (1) , M.H. Genest (1) , J.Y. Hostachy (1) , F. Ledroit-Guillon (1) , A. Lleres (1) , A. Lucotte (1) , F. Malek (1) , C. Monini (1) , J. Stark (1) , B. Trocmé (1) , M. Wu (1) , G. Rahal (2) , L. Alio (3) , M. Barbero (3) , J. C. Clémens (3) , Y. Coadou (3) , Sara Diglio (3) , F. Djama (3) , L. Feligioni (3) , J. Gao (3) , G.D. Hallewell (3) , D. Hoffmann (3) , F. Hubaut (3) , E. Le Guirriec (3) , B. Li (3) , D. Madaffari (3) , K. Mochizuki (3) , E. Monnier (3) , S. Muanza (3) , Y. Nagai (3) , P. Pralavorio (3) , A. Rozanov (3) , T. Serre (3) , M. Talby (3) , R.E. Ticse Torres (3) , S. Tisserant (3) , J. Toth (3) , F. Touchard (3) , M. Ughetto (3) , L. Vacavant (3) , S.J. Kahn (3) , E. B. F. G. Knoops (3) , S. Abdel Khalek (4) , A. Bassalat (4) , C. Becot (4) , S. Binet (4) , C. Bourdarios (4) , D. Charfeddine (4) , J.B. de Vivie De Regie (4) , L. Duflot (4) , M. Escalier (4) , L. Fayard (4) , D. Fournier (4) , E.L. Gkougkousis (4) , J.-F. Grivaz (4) , T. Guillemin (4) , F. Hariri (4) , S. Henrot-Versillé (4) , J. Hrivnac (4) , L. Iconomidou-Fayard (4) , M. Kado (4) , A. Lounis (4) , N. Makovec (4) , C. Nellist (4) , L. Poggioli (4) , P. Puzo (4) , A. Renaud (4) , D. Rousseau (4) , G. Rybkin (4) , A.C. Schaffer (4) , E. Scifo (4) , L. Serin (4) , S. Simion (4) , R. Tanaka (4) , H.L. Tran (4) , D. Zerwas (4) , Z. Zhang (4) , D. Boumediene (5) , Emmanuel Busato (5) , D. Calvet (5) , S. Calvet (5) , J. Donini (5) , E. Dubreuil (5) , N. Ghodbane (5) , G. Gilles (5) , Ph. Gris (5) , H. Liao (5) , R. Madar (5) , D. Pallin (5) , S.M. Romano Saez (5) , C. Santoni (5) , D. Simon (5) , Timothée Theveneaux-Pelzer (5) , F. Vazeille (5) , Z. Barnovska (6) , N. Berger (6) , M. Delmastro (6) , L. Di Ciaccio (6) , S. Elles (6) , T. Hryn’ova (6) , S. Jézéquel (6) , I. Koletsou (6) , R. Lafaye (6) , J. Leveque (6) , N. Massol (6) , G. Sauvage (6) , E. Sauvan (6) , O. Simard (6) , T. Todorov (6) , I. Wingerter-Seez (6)

1 LPSC - Laboratoire de Physique Subatomique et de Cosmologie
2 CC-IN2P3 - Centre de Calcul de l'IN2P3
3 CPPM - Centre de Physique des Particules de Marseille
4 LAL - Laboratoire de l'Accélérateur Linéaire
5 LPC - Laboratoire de Physique Corpusculaire - Clermont-Ferrand
6 LAPP - Laboratoire d'Annecy de Physique des Particules

A search for the decays of the Higgs and $Z$ bosons to $J/\psi\gamma$ and $\Upsilon(nS)\gamma$ ($n=1,2,3$) is performed with $pp$ collision data samples corresponding to integrated luminosities of up to $20.3\mathrm{fb}^{-1}$ collected at $\sqrt{s}=8\mathrm{TeV}$ with the ATLAS detector at the CERN Large Hadron Collider. No significant excess of events is observed above expected backgrounds and 95% CL upper limits are placed on the branching fractions. In the $J/\psi\gamma$ final state the limits are $1.5\times10^{-3}$ and $2.6\times10^{-6}$ for the Higgs and $Z$ bosons, respectively, while in the $\Upsilon(1S,2S,3S)\,\gamma$ final states the limits are $(1.3,1.9,1.3)\times10^{-3}$ and $(3.4,6.5,5.4)\times10^{-6}$, respectively.

Domaines: Physique des Hautes Energies - Expérience [hep-ex]

G. Aad, S. Albrand, J. Brown, J. Collot, S. Crépé-Renaudin, et al.. Search for Higgs and $Z$ Boson Decays to $J/\psi\gamma$ and $\Upsilon(nS)\gamma$ with the ATLAS Detector. Physical Review Letters, 2015, 114 (12), pp.121801. ⟨10.1103/PhysRevLett.114.121801⟩. ⟨in2p3-01103567⟩