FIZIKA B 7 (1998) 3, 155-169

A STUDY OF THE FOURTH-GENERATION QUARKS AND FCNC

SURATH KUMAR BISWAS and VINOD PRAKASH GAUTAM

e-mail: tpvpg@mahendra.iacs.res.in

Theoretical Physics Department, Indian Association for the Cultivation of Science, Jadavpur, Calcutta, 700032, India

Received 21 August 1998; Accepted 12 October 1998

The decay of the fourth-generation down-type quark bc® b\g and bc® bg has been studied as an extension of the standard model using evolution of the mass-based fourth generation CKM matrix with CP violation phase equal to zero. Range of the masses of fourth generation down-type quark bc and up-type quark tc have been taken with due observance of the constraint imposed by the present experimental value of the r parameter, keeping in view the mass difference of the fourth generation quark doublet. The decay width of \B also has been studied, however, with correction up to the leading QCD logarithms for six active flavours after the W boson, t and tc quarks have been integrated out using operator product expansion. Strong interaction coupling constant is taken on matching scale of Z boson mass.

PACS numbers: 12.15.Hb,  12.90.+b,  13.65.+i,  14.80.-j

UDC 539.126

Keywords: fourth-generation of quarks, decay and masses of down-type quark bc and up-type quark tc, r doublet, decay width of \B

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