CP violation in t → W + b decays in two-Higgs doublet model

Due to the large mass of top quark, CP violation in the top-quark decay is sensitive to the interactions mediated by Higgs bosons. We consider CP violation in t → W ⁺ b decay by calculating consistently in unitary gauge the CP-violating up-down asymmetry of the leptons from W boson decays in t → W ⁺ b, defined by Grz?dkowski and Gunion, in the two-Higgs doublet model with CP-violating neutral sector. The asymmetry is shown to be at most of the order of (1–4) × 10^-4 for tan β = 1.0, where tan β is the ratio of vacuum expectation values for the two neutral Higgs bosons.     

STUDY ON HIGH PERFORMANCE ANTI—WEAR ADDITIVES FROM WATER—SOLUBLE POLYMERIC LUBRICANT*

A series of high performance lubricants of water-soluble polymers with telechelic or starstructures has been studied. Their average molecular weights M are 1800--6000. The chemi-cal structures of the lubricants are characterized by their hydrophilic groups (--CH_2CH_2O--),--COOH, --OH, --CONH_2 and antiwear active elements (S, P,Zn and Mo). The results ofassessing for the anti-wear property indicate that this kind of water-soluble polymeric lubri-cants possesses excellent watersolubility, lubricity and anti-wear property. A preliminarystudy on the anti-wear mechanism of the polymers is performed by means of electron probeand scanning electron microscopy (SEM).     

Analysis of a fluorescence depletion process of Rhodamine 6G in a PMMA matrix induced by nano- and picosecond lasers

The two-color fluorescence depletion process of Rhodamine 6G in PMMA matrixes was investigated using nano- and picosecond lasers. Erase-lasers of 1064 and 599 nm depleted the fluorescence from the S₁ state. Fluorescence depletion with 1064 nm was analyzed by the up-conversion from state S₁ to S₂, while that with 599 nm was simulated based on both the up-conversion and the stimulated emission. A three-state model describes this process due to a nanosecond laser well, while it could not reproduce that by picosecond lasers. Significant contributions of vibrational relaxation in S₁ and re-absorption from S₀ are suggested in the picosecond region.