Percent-Level-Precision Physics at the Tevatron: Next-to-Next-to-Leading Order QCD Corrections to<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>q</mml:mi><mml:mover accent="true"><mml:mi>q</mml:mi><mml:mo>¯</mml:mo></mml:mover><mml:mo>→</mml:mo><mml:mi>t</mml:mi><mml:mover accent="true"><mml:mi>t</mml:mi><mml:mo>¯</mml:mo></mml:mover><mml:mo mathvariant="bold">+</mml:mo><mml:mi>X</mml:mi></mml:math>
Physical review letters