On the top-antitop invariant mass spectrum at the LHC from a Higgs boson signal perspective

We investigate the effect of one-loop corrections of O(alpha(2)(S)alpha w) on the invariant mass spectrum at the Large Hadron Collider (LHC) in presence of both resonant and non-resonant Higgs boson effects. We show that corrections of O(alpha(2)(S)alpha w) involving a non-resonant Higgs boson are comparable to or even larger than those involving interference with the s-channel resonant Higgs boson amplitude and that both of these are subdominant with respect to all other (non-Higgs) diagrams through that order. We also compute the contribution through O(alpha(2)(S)alpha(2)(w)) of resonant Higgs boson production (i.e. Higgs production via gg fusion) as well as the pure QCD ones of O(alpha(3)(S)). Altogether, we show that the well-known peak-dip structure of the M-t (t) over bar spectrum emerging from interference effects between the t, u-channel gg-induced Leading Order (LO) QCD diagrams and the one due to a Higgs boson in s-channel via gg-fusion is drastically swamped by the remainder of the terms of O(alpha(2)(S)alpha(w)) discussed above. (C) 2012 Elsevier B.V. All rights reserved.