Logarithmic corrections to O( $$a 2$$ a 2 ) effects in lattice QCD with unrooted staggered quarks

Abstract We derive the asymptotic lattice-spacing dependence $$a^2[2b_0\bar{g}^2(1/a)]^{\hat{\gamma }_i}$$ a 2 [ 2 b 0 g ¯ 2 ( 1 / a ) ] γ ^ i relevant for spectral quantities of lattice QCD, when using unrooted Staggered quarks. Without taking any effects from matching into account we find $$\min _i\hat{\gamma }_i\approx -0.273, -0.301, -0.913, -2.614$$ min i γ ^ i ≈ - 0.273 , - 0.301 , - 0.913 , - 2.614 for $$N_\textrm{f}=0,4,8,12$$ N f = 0 , 4 , 8 , 12 respectively. Common statements in the literature on the absence of mass-dimension 5 operators from the on-shell basis of the Symanzik Effective Field Theory action are being clarified for a description using strictly local tastes, here playing the role of continuum quark flavours. Potential impact of $$\textrmÓ}(a)$$ O ( a ) EOM-vanishing terms beyond spectral quantities is being discussed.