SU(3)breaking andD0−D0

Abstract

The main challenge in the Standard Model calculation of the mass and width difference in the D 0 − D 0 system is to estimate the size of SU (3) breaking effects. We prove that D meson mixing occurs in the Standard Model only at second order in SU (3) violation. We consider the possibility that phase space effects may be the dominant source of SU (3) breaking. We find that y = ∆Γ/2Γ of the order of one percent is natural in the Standard Model, potentially reducing the sensitivity to new physics of measurements of D meson mixing.

A vector-like heavy quark in the Littlest Higgs model

“…In contrast, long distance contributions to D 0 −D 0 mixing are inherently nonperturbative, and cannot be calculated from the first principles. Interestingly, mixing from the long distance effects can dominate over the short distance ones, and even reach the current experimental limit [14,15]. We now review the current experimental data for charm mixing.…”

“…In Ref. [14], it is asserted that the values of |x| and |y| are between 10 −3 and 10 −2 within the Standard Model. To check theoretical prediction more precisely, one need to improve sensitivity at least at 0.1% level in the future generation of charm collider experiments 1 .…”

Measurement of D⁰ - $\bar{D}$⁰ Mixing With a Time-Dependent Amplitude Analysis of D⁰ → K⁺π^- π⁰

“…To discern possible new physics contributions from the SM contributions to mixing, precise predictions on the x and y value are needed. It has been shown [7] that x and y are generated only at second order in flavor SU(3) F breaking in the SM, so schematically…”

“…In the m c >> Λ limit, where Λ is a scale characteristic of the strong interactions, ∆M and ∆Γ in Equation 1.5 can be expanded in terms of matrix elements of local operators [7]. For example, one can consider the width difference between the two mass eigenstates:…”

“…The inclusive approach is based on the operator product expansion (OPE) [7]. In the m c >> Λ limit, where Λ is a scale characteristic of the strong interactions, ∆M and ∆Γ in Equation 1.5 can be expanded in terms of matrix elements of local operators [7].…”