Search for the Higgs boson produced in association with a $W$ boson and decaying to four $b$-quarks via two spin-zero particles in $pp$ collisions at 13 TeV with the ATLAS detector

M. Aaboud , Z. Barnovska-Blenessy (1) , N. Berger (1) , M. Delmastro (1) , L. Di Ciaccio (1) , S. Elles (1) , K. Grevtsov (1) , T. Guillemin (1) , T. Hryn’ova (1) , S. Jézéquel (1) , I. Koletsou (1) , R. Lafaye (1) , Jérémy Lévêque (1) , P. Mastrandea (1) , G. Sauvage (1) , E. Sauvan (1) , B.H. Smart (1) , T. Todorov (1) , I. Wingerter-Seez (1) , E. Yatsenko (1) , D. Boumediene (2) , E. Busato (2) , D. Calvet (2) , S. Calvet (2) , A.R. Chomont (2) , J. Donini (2) , Ph. Gris (2) , R. Madar (2) , D. Pallin (2) , S.M. Romano Saez (2) , C. Santoni (2) , D. Simon (2) , F. Vazeille (2) , S. Albrand (3) , S. Berlendis (3) , A. Bethani (3) , C. Camincher (3) , J. Collot (3) , S. Crépé-Renaudin (3) , P.A. Delsart (3) , C. Gabaldon (3) , M.H. Genest (3) , P.O.J. Gradin (3) , J.Y. Hostachy (3) , F. Ledroit-Guillon (3) , A. Lleres (3) , A. Lucotte (3) , F. Malek (3) , E. Petit (3) , J. Stark (3) , B. Trocmé (3) , M. Wu (3) , G. Aad (4) , M. Alstaty (4) , M. Barbero (4) , A. Calandri (4) , T.P. Calvet (4) , Y. Coadou (4) , C. Diaconu (4) , Sara Diglio (4) , F. Djama (4) , V. Ellajosyula (4) , L. Feligioni (4) , J. Gao (4) , A. Hadef (4) , G.D. Hallewell (4) , F. Hubaut (4) , S.J. Kahn (4) , E. B. F. G. Knoops (4) , E. Le Guirriec (4) , J. Liu (4) , K. Liu (4) , D. Madaffari (4) , E. Monnier (4) , S. Muanza (4) , E. Nagy (4) , P. Pralavorio (4) , Y. Rodina (4) , A. Rozanov (4) , M. Talby (4) , T. Theveneaux-Pelzer (4) , R.E. Ticse Torres (4) , S. Tisserant (4) , J. Toth (4) , F. Touchard (4) , L. Vacavant (4) , Chen Wang (4) , M.K. Ayoub (5) , A. Bassalat (5) , S. Binet (2) , C. Becot , C. Bourdarios (5) , J.B. de Vivie De Regie (5) , D. Delgove (5) , L. Duflot (5) , M. Escalier (5) , L. Fayard (5) , D. Fournier (5) , E.L. Gkougkousis (5) , J.-F. Grivaz (5) , F. Hariri (5) , S. Henrot-Versille (5) , J. Hrivnac (5) , L. Iconomidou-Fayard (5) , M. Kado (5) , A. Lounis (5) , N. Makovec (5) , N. Morange (5) , C. Nellist (5) , P. Petroff (5) , L. Poggioli (5) , P. Puzo (5) , A. Renaud (5) , G. Rybkin (5) , D. Rousseau (5) , A.C. Schaffer (5) , L. Serin (5) , E. Scifo (5) , S. Simion (5) , R. Tanaka (5) , D. Zerwas (5) , Zhongkai Zhang (5) , Y. Zhao (5) , G. Rahal (6)

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

This paper presents a dedicated search for exotic decays of the Higgs boson to a pair of new spin-zero particles, $H \rightarrow aa$, where the particle $a$ decays to $b$-quarks and has a mass in the range of 20-60 GeV. The search is performed in events where the Higgs boson is produced in association with a $W$ boson, giving rise to a signature of a lepton (electron or muon), missing transverse momentum, and multiple jets from $b$-quark decays. The analysis is based on the full dataset of $pp$ collisions at $\sqrt{s} = 13$ TeV recorded in 2015 by the ATLAS detector at the CERN Large Hadron Collider, corresponding to an integrated luminosity of 3.2 fb$^{-1}$. No significant excess of events above the Standard Model prediction is observed, and a $95\%$ confidence-level upper limit is derived for the product of the production cross section for $pp \rightarrow WH$ times the branching ratio for the decay $H \rightarrow aa \rightarrow 4b$. The upper limit ranges from 6.2 pb for an $a$-boson mass $m_a = 20$ GeV to 1.5 pb for $m_a = 60$ GeV.

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

M. Aaboud, Z. Barnovska-Blenessy, N. Berger, M. Delmastro, L. Di Ciaccio, et al.. Search for the Higgs boson produced in association with a $W$ boson and decaying to four $b$-quarks via two spin-zero particles in $pp$ collisions at 13 TeV with the ATLAS detector. European Physical Journal C: Particles and Fields, 2016, 76, pp.605. ⟨10.1140/epjc/s10052-016-4418-9⟩. ⟨in2p3-01338745⟩