Energy and angular distributions of the bottom quark in the electron-positron annihilation $e^{+}{e}^{-}\to b{W}^{+}\bar{t}$

Abstract

The distributions of the bottom quark in the process $e^{+}{e}^{-}\to t\bar{t}\to b{W}^{+}\bar{t}$ are considered at the $e^{+}{e}^{-}$ energy corresponding to the first construction stage of the Compact Linear Collider. The cross sections of $e^{+}{e}^{-}\to b\dots$, as functions of the $b$-quark energy and angle with respect to the direction of the electron beam, are derived and calculated. The effects of physics beyond the Standard Model are included via the modified $\gamma t\bar{t}$ and $Zt\bar{t}$ couplings which naturally appear in effective field theories. In addition to the cross sections, the energy and angular asymmetries are calculated. The dependence of these observables on the $e^{+}{e}^{-}$ energy is calculated, and features of this dependence are investigated.

Comments: 16 pages, 7 figures, ws-ijmpa style; v3: Appendix A with discussion of gauge invariance and a few references added, published version