arXiv subjects
Publications and source records attributed to Yuichiro Kiyo.
We analyze spin correlations between top quark and anti-top quark produced at polarized e^+ e^- and gamma gamma colliders. We consider a generic spin basis to find a strong spin correlation. Optimal spin decompositions for top quark pair are presented for e^+ e^- and gamma gamma colliders. We show the cross-section in these bases and discuss the characteristics of results.
We analyze the spin correlations of the top quark pairs produced at Photon Linear Colliders. We employ the circular polarized photon beams and general spin basis for the top quark pair. We consider general spin bases to find a strong spin correlation between produced top quark and anti-top quark. We show the cross-section in these bases and discuss the characteristics of results.
The small $x$ behavior of the flavor non-singlet $g_{1}$ structure function is analysed numerically by taking into account the all-order resummation of $α_{s} \ln^{2}x $ terms. We include a part of the next-to-leading logarithmic corrections coming from the resummed ``coefficient function'' which are not considered in the literatures to respect the factorization scheme independence. The resummed coefficient function turns out to give unexpectedly large suppression effects over the experimentally accessible range of $x$ and $Q^{2}$. This fact implies that the higher order logarithmic corrections are very important for $g_{1}$ in the small $x$ region.
We numerically analyse the evolution of the flavor non-singlet $g_{1}$ structure function taking into account the all-order resummation of $α_{s} ln^{2}x$ terms which is expected to have much stronger effects than the DGLAP evolution in the small x region. We include a part of the next-to-leading logarithmic corrections coming from the resummed ``coefficient function'' which are not considered in the calculation of Blümlein and Vogt to respect the factorization scheme independence. It is pointed out that the resummed coefficient function gives unexpectedly large suppression factor over the experimentally accessible range of x and Q^{2}. This fact implies that the next-to-leading logarithmic contributions are very important for the $g_{1}$ structure function.