RADIATIVE-CORRECTIONS TO THE MUONIUM HYPERFINE-STRUCTURE .2. THE ALPHA(Z-ALPHA)(2) CORRECTION

This is the second of a series of papers on the radiative corrections of order alpha(2)(Z alpha), alpha(Z alpha)(2), and various logarithmic terms of order alpha(4), to the hyperfine structure of the muonium gr ound state. This paper deals with the alpha(Z alpha)(2) correction. Ba sed on the NRQED bound state theory, we isolated the term of order alp ha(Z alpha)(2) exactly. Our result +16.904 2 (11)alpha(Z alpha)E-2(F)/ pi for the non-logarithmic part is consistent with the alpha(Z alpha)( 2) part of Sapirstein's calculation and the recent result of Pachucki, and reduces the numerical uncertainty in the alpha(Z alpha)(2) term b y 2 orders of magnitude.