Measurement of the $\bar{B}_s^0\to D_s^-D_s^+$ and $\bar{B}_s^0\to D^-D_s^+$ effective lifetimes

R. Aaij , Y. Amhis (1) , S. Barsuk (1) , O. Callot (1) , J. He (1) , O. Kochebina (1) , J. Lefrançois (1) , F. Machefert (1) , A. Martin Sanchez (1) , M. Nicol (1) , P. Robbe (1) , M.-H. Schune (1) , M. Teklishyn (1) , A. Vallier (1) , B. Viaud (1) , E. Ben-Haim (2) , M. Benayoun (2) , P. David (2) , L. del Buono (2) , A. Martens (2) , D.A. Milanes (2) , F. Polci (2) , Ziad Zj Ajaltouni (3) , M. Baalouch (3) , E. Cogneras (3) , O. Deschamps (3) , I. El Rifai (3) , M. Grabalosa Gándara (3) , Pierre Henrard (3) , M. Hoballah (3) , R. Lefèvre (3) , S. Monteil (3) , V. Niess (3) , Pascal Perret (3) , Diego Alejandro Roa Romero (3) , E. Aslanides (4) , J. Cogan (4) , W. Kanso (4) , R. Legac (4) , O. Leroy (4) , G. Mancinelli (4) , E. Maurice (4) , A. Mordà (4, 5) , M. Perrin-Terrin (4) , M. Sapunov (4) , J. Serrano (4) , A. Tsaregorodtsev (4) , I. de Bonis (6) , D. Decamp (6) , N. Déléage (6) , Ph. Ghez (6) , J.-P. Lees (6) , I.V. Machikhiliyan (6) , M.-N. Minard (6) , B. Pietrzyk (6) , W. Qian (6) , S. t'Jampens (6) , V. Tisserand (6) , E. Tournefier (6)

1 LAL - Laboratoire de l'Accélérateur Linéaire
2 LPNHE - Laboratoire de Physique Nucléaire et de Hautes Énergies
3 LPC - Laboratoire de Physique Corpusculaire - Clermont-Ferrand
4 CPPM - Centre de Physique des Particules de Marseille
5 CPT - Centre de Physique Théorique - UMR 7332
6 LAPP - Laboratoire d'Annecy de Physique des Particules

The first measurement of the effective lifetime of the $\bar{B}_s^0$ meson in the decay $\bar{B}_s^0\to D_s^-D_s^+$ is reported using a proton-proton collision dataset, corresponding to an integrated luminosity of 3 fb$^{-1}$, collected by the LHCb experiment. The measured value of the $\bar{B}_s^0\to D_s^-D_s^+$ effective lifetime is $1.379\pm0.026\pm0.017$ ps, where the uncertainties are statistical and systematic, respectively. This lifetime translates into a measurement of the decay width of the light $\bar{B}_s^0$ mass eigenstate of \Gamma_L$=0.725\pm0.014\pm0.009$ ps$^{-1}$. The $\bar{B}_s^0$ lifetime is also measured using the flavor-specific $\bar{B}_s^0\to D^-D_s^+$ decay to be $1.52\pm0.15\pm0.01 {\rm ps}$.

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

R. Aaij, Y. Amhis, S. Barsuk, O. Callot, J. He, et al.. Measurement of the $\bar{B}_s^0\to D_s^-D_s^+$ and $\bar{B}_s^0\to D^-D_s^+$ effective lifetimes. Physical Review Letters, 2014, 112, pp.111802. ⟨10.1103/PhysRevLett.112.111802⟩. ⟨in2p3-00914272⟩