Tauonic B decays in the Minimal Supersymmetric Standard Model

We study new physics effects on B decay processes including a final $\tau$ particle, namely $B \to D \tau \nu$ and $B \to \tau \nu$. An important feature of these processes is that a charged Higgs boson can contribute to the decay amplitude at the tree level in models such as Two Higgs Doublet Model and the Minimal Supersymmetric Standard Model (MSSM). We derive a resummed effective Lagrangian for charged-Higgs mediated interactions in the MSSM with the Minimal Flavor Violation. Including supersymmetric (SUSY) loop corrections for down-type-quark and charged-lepton Yukawa couplings, we calculate the branching ratios of the $B \to D \tau \nu$ and $B \to \tau \nu$ processes. We find that SUSY correction due to gluino-sbottom diagrams can change the Higgs exchange contribution by $\pm50$%, whereas stau-neutralino diagrams can make corrections up to 20%. We also discuss relationship between SUSY corrections in the tauonic decays and flavor changing neutral current processes such as $B_s \to \mu^+\mu^-$ and $b \to s \gamma$.Comment: 29 pages, 22 figure

Area of Compaction to Prevent Uplift by Liquefaction

In this study, shaking table tests, upper seepage flow tests and numerical analyses were conducted to determine the condition of improvement by the compaction method, including the extent of area and the density, to prevent uplift of underground pipes by liquefaction. Based on the results of these investigations, a procedure to determine the improvement conditions was proposed

Scale-model test for disposal pit of high-level radioactive waste and theoretical evaluation on self-sealing of bentonite-based buffers

Bentonite is attracting greater attention in Japan and some other countries as a buffer for use in repositories of high-level radioactive waste (HLW). Bentonite-based buffers for HLW disposal are expected, because of their swelling deformation, to fill spaces between buffers and walls of disposal pits or between buffers and waste containers designated as overpack. Bentonite has a self-sealing capability. This study conducts scale-model tests simulating the relation between the buffer and interstitial space. It also investigates the validity of theoretical equations for swelling presented by Komine and Ogata (published in 2003 and 2004) to evaluate buffer self-sealing capabilities by comparing calculated and experimentally obtained results of scale-model tests. Results of the experimental work and calculations described herein highlight bentonite’s self-sealing capability and demonstrate the high applicability of these Komine and Ogata equations to quantify filling of interstitial spaces by bentonite-based buffer swelling.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Adaptations and countermeasures for mitigating impacts due to global warming in geotechnical and geoenvironmental engineering

This paper describes what will be happened by torrential rainfall and temperature rising due to global warming. It also introduces some examples of researches and developments concerning the mentioned-above which are being conducted in Ibaraki University. Especially, this paper describes vulnerability of river levees and banks against torrential rainfall and degradation of water quality of closed water environment s uch as lake/marsh which will be caused by temperature rising due to global warming. Furthermore, this paper mentions significance of aftercare in damage site by introducing an exemplum of utilization of disaster waste in the 2004 year Niigata Chuetsu earth quake. Consequently, it describes the author’s philosophy for adaptation and countermeasures against global warming