Author/Authors :
ALEPH Collaboration، نويسنده , , R. Barate، نويسنده , , D. Buskulic، نويسنده , , D. Decamp، نويسنده , , P. Ghez، نويسنده , , C. Goy، نويسنده , , S. Jezequel، نويسنده , , J.-P. Lees، نويسنده , , A. Lucotte، نويسنده , , F. Martin، نويسنده , , E. Merle، نويسنده , , M.-N. Minard، نويسنده , , Nief، Francois نويسنده , , B. Pietrzyk، نويسنده , , R. Alemany، نويسنده , , G. Boix، نويسنده , , M.P. Casado، نويسنده , , M. Chmeissani، نويسنده , , J.M. Crespo، نويسنده , , M. Delfino، نويسنده , , et al.، نويسنده ,
Abstract :
Searches for scalar top, scalar bottom and degenerate scalar quarks have been performed with data collected with the ALEPH detector at LEP. The data sample consists of 57 pb−1 taken at s = 181–184 GeV. No evidence for scalar top, scalar bottom or degenerate scalar quarks was found in the channels t̃→cχ, t̃→bℓν̃, b̃→bχ, and q̃→qχ. From the channel t̃→cχ a limit of 74 GeV/c2has been set on the scalar top quark mass, independent of the mixing angle. This limit assumes a mass difference between the t̃ and the χ in the range 10–40 GeV/c2. From the channel t̃→bℓν̃ the mixing-angle-independent scalar top limit is 82 GeV/c2, assuming mt̃−mν̃ > 10 GeV/c2. From the channel b̃→bχ, a limit of 79 GeV/c2has been set on the mass of the supersymmetric partner of the left-handed state of the bottom quark. This limit is valid for mb̃−mχ > 10 GeV/c2. From the channel q̃→qχ, a limit of 87 GeV/c2has been set on the mass of supersymmetric partners of light quarks assuming five degenerate flavours and the production of both “left-handed” and “right-handed” squarks. This limit is valid for mq̃−mχ > 5 GeV/c2.
