Search for Higgs bosons decaying to $aa$ in the $\mu\mu\tau\tau$ final state in $pp$ collisions at $\sqrt{s} = $ 8 TeV with the ATLAS experiment

G. Aad (1) , S. Albrand (2) , J. Brown (2) , J. Collot (2) , S. Crépé-Renaudin (2) , P.A. Delsart (2) , C. Gabaldon (2) , M.H. Genest (2) , J.Y. Hostachy (2) , F. Ledroit-Guillon (2) , A. Lleres (2) , A. Lucotte (2) , F. Malek (2) , C. Monini (2) , J. Stark (2) , B. Trocmé (2) , M. Wu (2) , G. Rahal (3) , M.K. Ayoub (4) , A. Bassalat (4) , C. Becot (4) , S. Binet (4) , C. Bourdarios (4) , J.B. de Vivie De Regie (4) , D. Delgove (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) , N. Morange (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) , Y. Zhao (4) , D. Boumediene (5) , Emmanuel Busato (5) , D. Calvet (5) , S. Calvet (5) , J. Donini (5) , E. Dubreuil (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) , M. Schwoerer (6) , O. Simard (6) , T. Todorov (6) , I. Wingerter-Seez (6) , E. Yatsenko (6) , L. Alio (1) , M. Barbero (1) , Y. Coadou (1) , C. Diaconu (1) , Sara Diglio (1) , F. Djama (1) , O. Duccu (1) , L. Feligioni (1) , J. Gao (1) , G.D. Hallewell (1) , F. Hubaut (1) , S.J. Kahn (1) , E. B. F. G. Knoops (1) , E. Le Guirriec (1) , J. Liu (1) , K. Liu (1) , D. Madaffari (1) , K. Mochizuki (1) , E. Monnier (1) , S. Muanza (1) , Y. Nagai (1) , E. Nagy (1) , P. Pralavorio (1) , A. Rozanov (1) , T. Serre (1) , M. Talby (1) , R.E. Ticse Torres (1) , E. Tiouchichine (1) , S. Tisserant (1) , J. Toth (1) , F. Touchard (1) , L. Vacavant (1)

1 CPPM - Centre de Physique des Particules de Marseille
2 LPSC - Laboratoire de Physique Subatomique et de Cosmologie
3 CC-IN2P3 - Centre de Calcul de l'IN2P3
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 decay to a pair of new particles of either the 125 GeV Higgs boson ($h$) or a second CP-even Higgs boson ($H$) is presented. The dataset correspods to an integrated luminosity of 20.3 fb$^{-1}$ of $pp$ collisions at $\sqrt{s}=$ 8 TeV recorded by the ATLAS experiment at the LHC in 2012. The search was done in the context of the next-to-minimal supersymmetric standard model, in which the new particles are the lightest neutral pseudoscalar Higgs bosons ($a$). One of the two $a$ bosons is required to decay to two muons while the other is required to decay to two $\tau$-leptons. No significant excess is observed above the expected backgrounds in the dimuon invariant mass range from 3.7 GeV to 50 GeV. Upper limits are placed on the production of $h\rightarrow{aa}$ relative to the Standard Model $gg\rightarrow{h}$ production, assuming no coupling of the $a$ boson to quarks. The most stringent limit is placed at 3.5\% for $m_a =$ 3.75 GeV. Upper limits are also placed on the production cross section of $H\rightarrow{aa}$ from 2.33 pb to 0.72 pb, for fixed $m_a$ = 5 GeV with $m_H$ ranging from 100 GeV to 500 GeV.

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

G. Aad, S. Albrand, J. Brown, J. Collot, S. Crépé-Renaudin, et al.. Search for Higgs bosons decaying to $aa$ in the $\mu\mu\tau\tau$ final state in $pp$ collisions at $\sqrt{s} = $ 8 TeV with the ATLAS experiment. Physical Review D, 2015, 95, pp.052002. ⟨10.1103/PhysRevD.92.052002⟩. ⟨in2p3-01150325⟩