Test of CP Invariance in vector-boson fusion production of the Higgs boson using the Optimal Observable method in the ditau decay channel with the ATLAS detector

G. Aad (1) , Z. Barnovska (2) , N. Berger (2) , M. Delmastro (2) , L. Di Ciaccio (2) , S. Elles (2) , K. Grevtsov (2) , T. Guillemin (2) , T. Hryn’ova (2) , S. Jézéquel (2) , I. Koletsou (2) , R. Lafaye (2) , J. Lévêque (2) , P. Mastrandea (2) , G. Sauvage (2) , E. Sauvan (2) , O. Simard (2) , B.H. Smart (2) , T. Todorov (2) , I. Wingerter-Seez (2) , E. Yatsenko (2) , D. Boumediene (3) , E. Busato (3) , D. Calvet (3) , S. Calvet (3) , A.R. Chomont (3) , J. Donini (3) , Ph. Gris (3) , H. Liao (3) , R. Madar (3) , D. Pallin (3) , S.M. Romano Saez (3) , C. Santoni (3) , D. Simon (3) , F. Vazeille (3) , L. Alio (1) , M. Barbero , A. Calandri (1) , T.P. Calvet (1) , Y. Coadou (1) , C. Diaconu (1) , Sara Diglio (1) , F. Djama (1) , V. Ellajosyula (1) , L. Feligioni (1) , J. Gao (1) , A. Hadef (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) , E. Nagy (1) , P. Pralavorio (1) , Y. Rodina (1) , A. Rozanov (1) , M. Talby (1) , T. Theveneaux-Pelzer (1) , R.E. Ticse Torres (1) , S. Tisserant (1) , J. Toth (1) , F. Touchard (1) , L. Vacavant (1) , Chen Wang (1) , S. Albrand (4) , S. Berlendis (4) , C. Camincher (4) , J. Collot (4) , S. Crépé-Renaudin (4) , P.A. Delsart (4) , C. Gabaldon (4) , M.H. Genest (4) , J.Y. Hostachy (4) , F. Ledroit-Guillon (4) , A. Lleres (4) , A. Lucotte (4) , F. Malek (4) , E. Petit (4) , J. Stark (4) , B. Trocmé (4) , M. Wu (4) , M.K. Ayoub (5) , A. Bassalat (5) , C. Bécot (5) , S. Binet (5) , C. Bourdarios (5) , D. Delgove (5) , J.-B. de Vivie de Regie (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) , D. Rousseau (5) , G. Rybkin (5) , A.C. Schaffer (5) , E. Scifo (5) , L. Serin (5) , S. Simion (5) , R. Tanaka (5) , D. Zerwas (5) , Z. Zhang (5) , Y. Zhao (5)

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

A test of CP invariance in Higgs boson production via vector-boson fusion using the method of the Optimal Observable is presented. The analysis exploits the decay mode of the Higgs boson into a pair of $\tau$ leptons and is based on 20.3 fb$^{-1}$ of proton-proton collision data at $\sqrt{s}$ = 8 TeV collected by the ATLAS experiment at the LHC. Contributions from CP-violating interactions between the Higgs boson and electroweak gauge bosons are described in an effective field theory framework, in which the strength of CP violation is governed by a single parameter $\tilde{d}$. The mean values and distributions of CP-odd observables agree with the expectation in the Standard Model and show no sign of CP violation. The CP-mixing parameter $\tilde{d}$ is constrained to the interval [-0.11,0.05] at 68% confidence level, consistent with the Standard Model expectation of $\tilde{d}=0$.

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

G. Aad, Z. Barnovska, N. Berger, M. Delmastro, L. Di Ciaccio, et al.. Test of CP Invariance in vector-boson fusion production of the Higgs boson using the Optimal Observable method in the ditau decay channel with the ATLAS detector. European Physical Journal C: Particles and Fields, 2016, 76, pp.658. ⟨10.1140/epjc/s10052-016-4499-5⟩. ⟨in2p3-01274774⟩