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

Abstract

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 q sl 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 s sl = (2.06 ± 0.18) • 10 −5 and a d sl = (−4.73 ± 0.42) • 10 −4 .

Penguin contribution to the width difference and CP asymmetry in Bq−B¯q mixing at order Asatrian1, Asatryan2, Hovhannisyan3 et al. 2020Phys. Rev. D204241View full textAdd to dashboardCite

“…The central values of all our MS scheme results are in excellent agreement with Ref. [38]. Our error estimate of the Λ QCD =m b corrections is conservative, as we add the errors of individual bag parameters linearly, leading to overall uncertainties in ΔΓ q =ΔM q which are larger by roughly a factor of 1.5 compared to those of ΔΓ q in Ref.…”

“…Our uncertainties for a q fs , though, are smaller compared to Ref. [38], as we find a smaller μ 1 dependence and assume a smaller error on m c . (Recall that a q fs ∝ m 2 c .)…”

“…Our error estimate of the Λ QCD =m b corrections is conservative, as we add the errors of individual bag parameters linearly, leading to overall uncertainties in ΔΓ q =ΔM q which are larger by roughly a factor of 1.5 compared to those of ΔΓ q in Ref. [38]. Our uncertainties for a q fs , though, are smaller compared to Ref.…”

Implications for new physics from a novel puzzle in B¯(s)0→Iguro1, Kitahara2 2020Phys. Rev. D311240View full textAdd to dashboardCite

“…It is checked that such a new physics contribution is compatible with data of the total decay rates of the B-mesons, τ B s =τ B d , and a fs d [1,[19][20][21]. Another potentially strong constraint comes from the kaon hadronic decays (s → uūd).…”

Improved model-independent determination of the strong-phase difference between D0 and D¯0→KAblikim1, Ачасов2, Adlarson3 et al. 2020Phys. Rev. D11010View full textAdd to dashboardCite

“…The value of γ measured with such tree-level transitions is insensitive to loop-level contributions [3]. Therefore, tests for new physics that are made by comparing unitarity triangle parameters measured using tree and loop processes can be improved by more precise determinations of γ [4,5].…”