Top quark production near threshold and the top quark mass

Abstract

We consider top-anti-top production near threshold in $e^+ e^-$ collisions, resumming Coulomb-enhanced corrections at next-to-next-to-leading order (NNLO). We also sum potentially large logarithms of the small top quark velocity at the next-to-leading logarithmic level using the renormalization group. The NNLO correction to the cross section is large, and it leads to a significant modification of the peak position and normalization. We demonstrate that an accurate top quark mass determination is feasible if one abandons the conventional pole mass scheme and if one uses a subtracted potential and the corresponding mass definition. Significant uncertainties in the normalization of the $t\bar{t}$ cross section, however, remain.Comment: 14 pages, LaTeX, 2 figures included via epsf.st

Heavy quark pair production near threshold with potential non-relativistic QCD

“…[34]. Nevertheless, they can be exactly related with each other by field redefinitions (in four and D dimensions).…”

“…The Green function at the origin has a ultraviolet divergence that manifests itself as a pole 1/ǫ. Using MS subtraction and then taking the limit ǫ → 0 we find [34,35] …”

“…In Appendix A we list the integrals that are needed and present the explicit results obtained in Ref. [34].…”

Soft gluon resummation for associated t t ¯ H $$ \mathrm{t}\overline{\mathrm{t}}\mathrm{H} $$ production at the LHC

“…We note that in general Coulomb corrections can also be resummed [46][47][48][49][50]. A combined resummation of Coulomb and soft corrections is, however, beyond the scope of this paper.…”

Enhancing thj production from top-Higgs FCNC couplings

“…In particular, top quark, as the heaviest SM fermion, owns the strongest Yukawa coupling and has the preference to reveal the new interactions at the electroweak scale [5][6][7][8][9][10][11][12][13][14]. 2 One of the interesting things is that the top quark is just heavier than the observed Higgs boson, which makes the top quark flavor changing neutral current (FCNC) processes t → hq (q = u, c) be accessible in kinematics.…”