Beam polarization effects on top-pair production at the ILC

Abstract

Full one-loop electroweak corrections for an e − e + → tt process associated with sequential t → bμν μ decay are discussed. At the one-loop level, the spinpolarization effects of the initial electron and positron beams are included in the total and differential cross sections. A narrow-width approximation is used to treat the top-quark production and decay while including full spin correlations between them. We observed that the radiative corrections due to the weak interaction have a large polarization dependence on both the total and the differential cross sections. Therefore, experimental observables that depend on angular distributions such as the forward-backward asymmetry of the top-production angle must be treated carefully including radiative corrections. We also observed that the energy distribution of bottom quarks is largely affected by the radiative corrections.

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

“…1. These results are the same as those included in our previous report [14] for a simple NLO correction. The consistency between our current and previous results [5,7,8] was numerically confirmed after adjustment of the input parameters.…”

“…Recently, electroweak radiative corrections for the process e − e + → tt → bbμ + μ − ν μνμ including the spinpolarization effects have been reported [14] by the authors of a present report. Unfortunately, a complete electroweak correction for the six-body final-state is impossible based on the current limits of computing power because the number of Feynman diagrams concerned is too large.…”

“…In Ref. [14], authors used a simple narrow width approximation (NWA) for the top-quark production and decay. A more precise method to treat both production and decay at a one loop-order is the double-pole approximation method.…”

Full \(\mathcal{O}(\alpha)\) Electroweak Radiative Corrections to \(e^-e^+ \rightarrow W^-W^+\) with Initial Beam Polarization Effects

“…[4]. In GRACE program, the polarized degrees for electron and positron have been implemented by using projection operators [13] as follows:…”

Full . Full O(α) electroweak radiative corrections to e^+ e^-→ZH with beam polarizations at the ILCO(α) electroweak radiative corrections to e^+ e^-→ZH with beam polarizations at the ILC

“…[17]. The polarizations for initial beam have been also included in this program [18]. Both new features are used for the calculations in this report.…”