13,951 research outputs found
Constraint on the branching ratio of B_c \to tau nu from LEP1 and consequences for R(D(*)) anomaly
Recently there has been interest in the correlation between R(D*) and the
branching ratio (BR) of in models with a charged scalar
H^\pm. Any enhancement of R(D*) by alone (in order to agree with
current data) also enhances ), for which there has been no
direct search at hadron colliders. We show that LEP data taken at the Z peak
requires BR() < 10%, and this constraint is significantly
stronger than the recent constraint BR() < 30% from
considering the lifetime of B_c. In order to respect this new constraint, any
explanation of the R(D) and R(D*) anomaly in terms of alone would
require the future measurements of R(D*) to be even closer to the Standard
Model prediction. A stronger limit on BR() (or its first
measurement) would be obtained if the L3 collaboration used all its data taken
at the Z peak.Comment: 14 pages, 4 figures, a reference and two sentences adde
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