Radiative corrections toπl2decays

Abstract

Radiative corrections to (r(2 (I =e or p) decays are examined. Higher order electroweak leading logarithms, short-distance QCD corrections, and structure dependent effects are incorporated. The results are employed to (1) test e-p universality in I ((r ev, (y))/1 ((r pv"(y)), (2) extract an f, which is used to check the CJoldberger-Treiman relation and PCAC-anomaly prediction for r((r yy), and (3)

Search for nonstandard modelCPorTviolation at theτ-charm factory

“…GeV [42,43] and the measurement value Γ exp (τ → Kν τ ) = (0.149 ± 0.051) × 10 −13 GeV for the τ → Kν τ decay width we obtain…”

“…For model 5 there is CP/T violation effect only in the second type process, which is determined by λ 32 λ ′ 31 * . A direct constraint on these parameters can be obtained through comparing the theoretical value Γ th (τ → πν τ ) = (2.480 ± 0.025) × 10 −13 GeV and the measurement value of Γ exp (τ → πν τ ) = (2.605 ± 0.093) × 10 −13 GeV [42]. Assuming that real and imaginary part of the coupling λλ ′ * are approximately equal, one has from τ → πν τ [18] |Im(…”

Radiative corrections in Kℓ30 decays

“…[17], the total radiative corrections to the K 0 e3 and the K 0 µ3 modes are (3.5 ± 0.3)% and (4.1 ± 0.3)%. The uncertainty in the total radiative corrections are dominated by the uncertainty in the long-distance component.…”

“…The radiative correction, δ ℓ T , is the sum of two components [31]: the short-distance (δ SD ) and long-distance (δ ℓ LD ) correction. Including the effects of quantum chromodynamics (QCD), the short distance radiative correction is [17] …”

“…This parameter is the sum of two contributions: the long-distance (δ ℓ LD ) and the short-distance (δ SD ) components. The short-distance parameter is known [17] and we calculate the long-distance corrections using a phenomenological model originally used in Refs. [18,19,20,21,22,23,24].…”