Search for invisible particles produced in association with single-top-quarks in proton-proton collisions at $\sqrt{s}$ = 8 TeV with the ATLAS detector

G. Aad (1) , S. Albrand (2) , J. Brown (2) , J. Collot (2) , S. Crépé-Renaudin (2) , B. Dechenaux (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) , Z. Barnovska (4) , N. Berger (4) , M. Delmastro (4) , L. Di Ciaccio , T.K.O. Doan (4) , S. Elles (4) , C. Goy (4) , T. Hryn’ova , S. Jézéquel (4) , H. Keoshkerian (4) , I. Koletsou (4) , R. Lafaye (4) , J. Leveque , V.P. Lombardo (4) , N. Massol (4) , H. Przysiezniak (4) , G. Sauvage (4) , E. Sauvan (4) , M. Schwoerer (4) , O. Simard (4) , T. Todorov (4) , I. Wingerter-Seez (4) , S. Abdel Khalek (5) , A. Bassalat (5) , C. Becot (5) , S. Binet (5) , C. Bourdarios (5) , J.B. de Vivie de Regie (5) , L. Duflot (5) , M. Escalier (5) , L. Fayard (5) , D. Fournier (5) , J.-F. Grivaz (5) , T. Guillemin (5) , F. Hariri (5) , S. Henrot-Versillé (5) , J. Hrivnac (5) , L. Iconomidou-Fayard (5) , M. Kado (5) , A. Lounis (5) , N. Makovec (5) , L. Poggioli (5) , P. Puzo (5) , A. Renaud (5) , D. Rousseau (5) , G. Rybkin (5) , A.C. Schaffer (5) , E. Scifo (5) , L. Serin (5) , S. Simion (5) , R. Tanaka (5) , H.L. Tran (5) , D. Zerwas (5) , Z. Zhang (5) , L. Alio (1) , M. Barbero (1) , J. C. Clémens (1) , Y. Coadou (1) , Sara Diglio (1) , F. Djama (1) , L. Feligioni (1) , G.D. Hallewell (1) , D. Hoffmann (1) , F. Hubaut (1) , E. B. F. G. Knoops (1) , E. Le Guirriec (1) , B. Li (1) , D. Madaffari (1) , K. Mochizuki (1) , E. Monnier (1) , S. Muanza (1) , Y. Nagai (1) , P. Pralavorio (1) , A. Rozanov (1) , T. Serre (1) , M. Talby (1) , E. Tiouchichine (1) , S. Tisserant (1) , J. Toth (1) , F. Touchard (1) , M. Ughetto (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 LAPP - Laboratoire d'Annecy de Physique des Particules
5 LAL - Laboratoire de l'Accélérateur Linéaire

A search for the production of single-top-quarks in association with missing energy is performed in proton--proton collisions at a centre-of-mass energy of $\sqrt{s}$ = 8 TeV with the ATLAS experiment at the Large Hadron Collider using data collected in 2012, corresponding to an integrated luminosity of 20.3 fb$^{-1}$. In this search, the $W$ boson from the top quark is required to decay into an electron or a muon and a neutrino. No deviation from the Standard Model prediction is observed, and upper limits are set on the production cross-section for resonant and non-resonant production of an invisible exotic state in association with a right-handed top quark. In the case of resonant production, for a spin-$0$ resonance with a mass of 500 GeV, an effective coupling strength above 0.15 is excluded at 95% confidence level for the top quark and an invisible spin-$1/2$ state with mass between 0 GeV and 100 GeV. In the case of non-resonant production, an effective coupling strength above 0.2 is excluded at 95% confidence level for the top quark and an invisible spin-$1$ state with mass between 0 GeV and 657 GeV.

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

G. Aad, S. Albrand, J. Brown, J. Collot, S. Crépé-Renaudin, et al.. Search for invisible particles produced in association with single-top-quarks in proton-proton collisions at $\sqrt{s}$ = 8 TeV with the ATLAS detector. European Physical Journal C: Particles and Fields, 2015, 75 (2), pp.79. ⟨10.1140/epjc/s10052-014-3233-4⟩. ⟨in2p3-01076068⟩