Model-independent bounds on new physics effects in non-leptonic tree-level decays of B-mesons
Alexander Lenz, Gilberto Tetlalmatzi-Xolocotzi
Abstract
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 $$ {a}_{sl}^q $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>a</mml:mi> <mml:mi>sl</mml:mi> <mml:mi>q</mml:mi> </mml:msubsup> </mml:math> 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 , $$ {a}_{sl}^q $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>a</mml:mi> <mml:mi>sl</mml:mi> <mml:mi>q</mml:mi> </mml:msubsup> </mml:math> = (2 . 06 ± 0 . 18) · 10 − 5 and $$ {a}_{sl}^d $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>a</mml:mi> <mml:mi>sl</mml:mi> <mml:mi>d</mml:mi> </mml:msubsup> </mml:math> = ( − 4 . 73 ± 0 . 42) · 10 − 4 .