We present the calculation of the short-distance power corrections to the CP-violation parameter εK coming from dimension-8 operators in the ∆S = 2 effective Hamiltonian. A first estimate of this contribution, obtained for large-Nc and in the chiral limit, was provided in ref. [1]. Here we evaluate and include the O(mK^2/mc^2) and O(ΛQCD^2/mc^2) contributions that, a priori, could induce O(1) corrections to previous estimates, as mK is numerically of order ΛQCD. Our computation shows that there are several dimension-8 operators besides the one considered before. Their effect on εK, however, accidentally cancels out to a large extent, leaving the final correction at the level of 1%.
Ciuchini, M., Franco, E., Lubicz, V., Martinelli, G., Silvestrini, L., Tarantino, C. (2022). Power corrections to the CP-violation parameter εK. JOURNAL OF HIGH ENERGY PHYSICS, 2022(2) [10.1007/JHEP02(2022)181].
Power corrections to the CP-violation parameter εK
Ciuchini M.;Lubicz V.;Martinelli G.;Silvestrini L.;Tarantino C.
2022-01-01
Abstract
We present the calculation of the short-distance power corrections to the CP-violation parameter εK coming from dimension-8 operators in the ∆S = 2 effective Hamiltonian. A first estimate of this contribution, obtained for large-Nc and in the chiral limit, was provided in ref. [1]. Here we evaluate and include the O(mK^2/mc^2) and O(ΛQCD^2/mc^2) contributions that, a priori, could induce O(1) corrections to previous estimates, as mK is numerically of order ΛQCD. Our computation shows that there are several dimension-8 operators besides the one considered before. Their effect on εK, however, accidentally cancels out to a large extent, leaving the final correction at the level of 1%.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
