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FIZIKA B 11 (2002) 2, 103-114
 
STUDY OF RADIATIVE B-DECAY CONSIDERING TWO-HIGGS-DOUBLET MODELS AND THE
FOURTH GENERATION IN THE QUARK SECTOR
HARAPRASAD ROY, SURATH KUMAR BISWAS and VINOD P. GAUTAM
Theoretical Physics Department, Indian Association for the Cultivation
of Science, Jadavpur, Kolkata-700032, India
E-mail address: tpdpb@mahendra.iacs.res.in
Received 15 December 2000 ; revised manuscript received 8 June 2002
Accepted 6 September 2002 Online 7 February 2003
Considering the nonstandard indirect effect of Yukawa couplings of the Higgs doublet to
the quarks, we examine strong-interaction effects in weak radiative B-meson decay. The
virtual effects of the Model I and Model II in the penguin-type diagram on the b® sg decay have been tested considering
the possibility of the fourth generation in quark sector, with corrections up to the
leading QCD logarithms, using evolution of the fourth-generation CKM matrix, with CP
violation phase equal to zero. Range of the masses of the fourth-generation down-type
quark b¢ and up-type quark t¢ have
been taken with due consideration 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. As a by-product, it is observed that the CLEO
bound clearly sets the lower bound on the Higgs boson mass at 220 GeV, which is above the
top quark mass.
PACS numbers: 12.60.-i
UDC 539.126
Keywords: weak radiative B-meson decay, fourth generation, Higgs boson mass
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