Search for scalar top and scalar bottom quarks at √s = 189 GeV at LEP

G Abbiendi; K Ackerstaff; G Alexander; J Allison; N Altekamp; KJ Anderson; S Anderson; S Arcelli; S Asai; SF Ashby; D Axen; G Azuelos; AH Ball; E Barberio; RJ Barlow; JR Batley; S Baumann; J Bechtluft; T Behnke; KW Bell; G Bella; A Bellerive; S Bentvelsen; S Bethke; S Betts; O Biebel; A Biguzzi; V Blobel; IJ Bloodworth; P Bock; J Bohme; D Bonacorsi; M Boutemeur; S Braibant; P Bright-Thomas; L Brigliadori; RM Brown; HJ Burckhart; P Capiluppi; RK Carnegie; AA Carter; JR Carter; CY Chang; DG Charlton; D Chrisman; C Ciocca; PEL Clarke; E Clay; I Cohen; JE Conboy; OC Cooke; C Couyoumtzelis; RL Coxe; M Cuffiani; S Dado; GM Dallavalle; R Davis; S de Jong; A de Roeck; P Dervan; K Desch; B Dienes; MS Dixit; J Dubbert; E Duchovni; G Duckeck; IP Duerdoth; PG Estabrooks; E Etzion; F Fabbri; A Fanfani; M Fanti; AA Faust; F Fiedler; M Fierro; I Fleck; R Folman; A Frey; A Fürtjes; DI Futyan; P Gagnon; JW Gary; J Gascon; SM Gascon-Shotkin; G Gaycken; C Geich-Gimbel; G Giacomelli; P Giacomelli; V Gibson; WR Gibson; DM Gingrich; D Glenzinski; J Goldberg; W Gorn; C Grandi; K Graham; E Gross; J Grunhaus; M Gruwé; GG Hanson

Journal article

Search for scalar top and scalar bottom quarks at √s = 189 GeV at LEP

G Abbiendi, K Ackerstaff, G Alexander, J Allison, N Altekamp, KJ Anderson, S Anderson, S Arcelli, S Asai, SF Ashby, D Axen, G Azuelos, AH Ball, E Barberio, RJ Barlow, JR Batley, S Baumann, J Bechtluft, T Behnke, KW Bell Show all

Physics Letters Section B Nuclear Elementary Particle and High Energy Physics | ELSEVIER SCIENCE BV | Published : 1999

DOI: 10.1016/S0370-2693(99)00440-2

Abstract

Searches for a scalar top quark and a scalar bottom quark have been performed using a data sample of 182 pb-1 at a centre-of-mass energy of √s = 189 GeV collected with the OPAL detector at LEP. No evidence for a signal was found. The 95% confidence level (C.L.) lower limit on the scalar top quark mass is 90.3 GeV if the mixing angle between the supersymmetric partners of the left- and right-handed states of the top quark is zero. In the worst case, when the scalar top quark decouples from the Z0 boson, the lower limit is 87.2 GeV. These limits were obtained assuming that the scalar top quark decays into a charm quark and the lightest neutralino, and that the mass difference between the scala..

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