ϵ/ϵ\epsilon' / \epsilon at the Next-to-leading order in QCD and QED

Nov, 1992
20 pages
Published in:
  • Phys.Lett.B 301 (1993) 263-271
e-Print:
Report number:
  • ROME-911-1992

Citations per year

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Abstract:
We present a new calculation of the CP violation parameter ϵ /ϵ\epsilon~{\prime}/ \epsilon. The results reported in this paper have been obtained by using the ΔS=1\Delta S=1 effective Hamiltonian computed at the next-to-leading order, including QCD and QED penguins. The matrix elements of the relevant operators have been taken from lattice QCD, at a scale μ=2\mu=2 GeV. At this relatively large scale, the perturbative matching between the relevant operators and the corresponding coefficients is quite reliable.\par The effect of the next-to-leading corrections is to lower the prediction obtained at the leading order, thus favouring the experimental result of E731. We analyze different contributions to the final result and compare the leading and next-to-leading cases.
  • CP: violation
  • effective Hamiltonian
  • quantum chromodynamics
  • quantum electrodynamics
  • lattice field theory: B-parameter
  • operator product expansion
  • numerical calculations: interpretation of experiments