arXiv subjects

T. Jujo

Publications and source records attributed to T. Jujo.

3 recordsLinked to original sources

arXiv2012

Pair-production and Three-body Decay of the Lighter Stop at the ILC in One-loop Order in the MSSM

We have been developing a program package called GRACE/SUSY-loop which automatically calculates the MSSM amplitudes in one-loop order. We present numerical results of calculations for pair-production and three-body decay of the lighter stop ($\widetilde{t}_1$) at the International Linear Collider (ILC) using GRACE/SUSY-loop. Since the distributions of missing transverse energy (MET) depend on mass spectrum of SUSY particles, we consider two scenarios on three-body decay of $\widetilde{t}_1$. In these scenarios, both QCD and EW corrections have positive sign for decay widths and cross sections.

hep-ph↗

arXiv1999

A Possible Mechanism of the Pseudogap in Organic Superconductor Based on the Superconducting Fluctuation

The explanation of the anomalous behavior in $κ$-type (BEDT-TTF)$_2$X which was revealed by the nuclear magnetic resonance experiments is presented. We calculate the electronic properties by using the one-loop approximation for the superconducting fluctuation. The decrease of the density of states due to the large damping effect is obtained and the one-particle spectrum has a pseudogap structure around the Fermi level. It is found that these behaviors are peculiar to the quasi two-dimensional system and are enhanced in the incoherent metal. The similarity between the cuprates and this compounds is discussed and an experiment to check this proposal is suggested.

cond-mat.supr-con↗

arXiv1999

Perturbation Theory on the Transition Temperature and Electronic Properties of Organic Superconductor

We study the superconducting transition temperature and the electronic properties of the metallic phase of $κ$-type (BEDT-TTF)$_2$X which shows unconventional properties in experiments, on the basis of the third order perturbation theory for a simple effective Hubbard model of a nearly triangular lattice. Appropriate transition temperatures and $d_{x^2-y^2}$ symmetry of the gap function are obtained in good agreement with experimental results. We also calculate the transition temperature by the fluctuation-exchange approximation(FLEX) in order to compare the two approaches; FLEX gives higher transition temperatures rather than the perturbation approach. However, it is also found that the vertex corrections, which are ignored in FLEX, have a crucial effect on $T_{\rm c}$ for strongly frustrated systems. The density of states and the normal self-energy calculated in this perturbation scheme show the nature of the conventional Fermi liquid near the Mott-insulator. Thus, our perturbation approach is applicable to the conventional metallic phase of this compound, while it cannot explain the (pseudo-)spin gap phenomenon which signals the non-Fermi liquid.

cond-mat.supr-con↗