Model-independent bounds on new physics effects in non-leptonic tree-level decays of B-mesons

摘要

A bstract We present a considerably improved analysis of model-independent bounds on new physics effects in non-leptonic tree-level decays of B-mesons. Our main finding is that contributions of about ± 0 . 1 to the Wilson coefficient of the colour-singlet operator Q _(2)of the effective weak Hamiltonian and contributions in the range of ± 0 . 5 (both for real and imaginary part) to Q _(1)can currently not be excluded at the 90% C.L. . Effects of such a size can modify the direct experimental extraction of the CKM angle γ by up to 10~( ° )and they could lead to an enhancement of the decay rate difference ?Γ_( d )of up to a factor of 5 over its SM value — a size that could explain the D0 dimuon asymmetry. Future more precise measurements of the semi-leptonic asymmetries a sl q documentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} egin{document}$$ {a}_{sl}^q $$end{document} and the lifetime ratio τ ( B _( s ))/ τ ( B _( d )) will allow to shrink the bounds on tree-level new physics effects considerably. Due to significant improvements in the precision of the non-perturbative input we update all SM predictions for the mixing obervables in the course of this analysis, obtaining: ? M _( s )= (18 . 77 ± 0 . 86) ps~( ? 1), ? M _( d )= (0 . 543 ± 0 . 029) ps~( ? 1), ?Γ_( s )= (9 . 1 ± 1 . 3) · 10~( ? 2)ps~( ? 1), ?Γ d = (2 . 6 ± 0 . 4) · 10~( ? 3)ps~( ? 1), a sl q documentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} egin{document}$$ {a}_{sl}^q $$end{document} = (2 . 06 ± 0 . 18) · 10~( ? 5)and a sl d documentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} egin{document}$$ {a}_{sl}^d $$end{document} = ( ? 4 . 73 ± 0 . 42) · 10~( ? 4).