$\mathcal{O}({\alpha }^2)$ ISR effects with a full electroweak one-loop correction for a top pair-production at the ILC

Abstract

Precise predictions for an $e^{+}{e}^{-}\to t\bar{t}$ cross section are presented at an energy region from 400 GeV to 800 GeV. Cross sections are estimated including the beam-polarization effects with full $\mathcal{O}(\alpha )$, and also with effects of the initial-state photon emission. A radiator technique is used for the initial-state photon emission up to two-loop order. A weak correction is defined as the full electroweak corrections without the initial-state photonic corrections. As a result, it is obtained that the total cross section of a top quark pair-production receives the weak corrections of $+4\%$ over the trivial initial state corrections at a centre of mass energy of 500 GeV. Among the initial state contributions, a contribution from two-loop diagrams gives less than $0.11\%$ correction over the one-loop ones at the center of mass energies of from $400$ GeV to $800$ GeV. In addition, an effect of a running coupling constant is also discussed.

Comments: Comments: 12 pages, 5 figures. Prepared for JHEP. Portions of this work previously appeared as arXiv:1706.07042, on which this heavily draws