A Microscopic Mechanism for Muscle's Motion

The SIRM (Stochastic Inclined Rods Model) proposed by H. Matsuura and M. Nakano can explain the muscle's motion perfectly, but the intermolecular potential between myosin head and G-actin is too simple and only repulsive potential is considered. In this paper we study the SIRM with different complex potential and discuss the effect of the spring on the system. The calculation results show that the spring, the effective radius of the G-actin and the intermolecular potential play key roles in the motion. The sliding speed is about $4.7\times10^{-6}m/s$ calculated from the model which well agrees with the experimental data.Comment: 9 pages, 6 figure

Tetrahedrally bonded ternary amorphous semiconductor alloys

The properties of tetrahedrally bonded ternary amorphous semiconductors a-CSiSn:H and a-CSiGe:H are reviewed with particular emphasis on the temperature dependence of dark conductivity and the coordination in random networks. It is shown here that the dark conductivity as a function of the temperature strongly depends on the carbon content and, more precisely, on the proportion of sp3 and sp2 sites in the carbon. Ternary alloys with different carbon contents are compared to binary alloys using the average coordination number. The ternary alloys have an average coordination number close to the optimal value predicted for amorphous covalent networks

Ab-Initio Calculation of Molecular Aggregation Effects: a Coumarin-343 Case Study

We present time-dependent density functional theory (TDDFT) calculations for single and dimerized Coumarin-343 molecules in order to investigate the quantum mechanical effects of chromophore aggregation in extended systems designed to function as a new generation of sensors and light-harvesting devices. Using the single-chromophore results, we describe the construction of effective Hamiltonians to predict the excitonic properties of aggregate systems. We compare the electronic coupling properties predicted by such effective Hamiltonians to those obtained from TDDFT calculations of dimers, and to the coupling predicted by the transition density cube (TDC) method. We determine the accuracy of the dipole-dipole approximation and TDC with respect to the separation distance and orientation of the dimers. In particular, we investigate the effects of including Coulomb coupling terms ignored in the typical tight-binding effective Hamiltonian. We also examine effects of orbital relaxation which cannot be captured by either of these models

An Upper Bound on the Decay tau -> mu gamma from Belle

We have performed a search for the lepton-flavor-violating decay tau -> mu gamma using a data sample of 86.3fb^{-1} accumulated by the Belle detector at KEK. No evidence for a signal is seen, and we set an upper limit for the branching fraction of B(tau -> mu gamma) < 3.1 x 10^{-7} at the 90% confidence level.Comment: 6 pages, 4 figuresm, submitted to Phys. Rev. Let

Measurement of Time-Dependent CP-Violating Asymmetries in B0 --> phi Ks0, K+ K- Ks0, and eta' Ks0 Decays

We present an improved measurement of CP-violation parameters in B0 --> phi Ks0, K+ K- Ks0, and eta' Ks0 decays based on a 140 fb-1 data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB energy-asymmetric e+e- collider. One neutral B meson is fully reconstructed in one of the specified decay channels, and the flavor of the accompanying B meson is identified from its decay products. CP-violation parameters for each of the three modes are obtained from the asymmetries in the distributions of the proper-time intervals between the two B decays. We find that the observed CP asymmetry in the B0 --> phi Ks0 decay differs from the standard model (SM) expectation by 3.5 standard deviations, while the other cases are consistent with the SM.Comment: 10 pages, 4 postscript figures, submitted to Physical Review Letters, also contributed to the XXI International Symposium on Lepton and Photon Interactions at High Energies, Aug 11-16, 2003, Fermilab, Illinois US

Measurements of the DsJD_{sJ} resonance properties

We report measurements of the properties of the $D_{sJ}^+(2317)$ and $D_{sJ}^+(2457)$ resonances produced in continuum $e^+ e^-$ annihilation near $\sqrt{s}=10.6 \mathrm{GeV}$. The analysis is based on an $86.9 \mathrm{fb^{-1}}$ data sample collected %at and 60 MeV below the $\Upsilon(4S)$ resonance with with the Belle detector at KEKB. We determine the masses to be $M(D_{sJ}^+(2317)) = 2317.2 \pm 0.5(\mathrm{stat}) \pm 0.9(\mathrm{syst}) \mathrm{MeV}/c^2$ and $M(D_{sJ}^+(2457))=2456.5 \pm 1.3(\mathrm{stat}) \pm 1.3(\mathrm{syst}) \mathrm{MeV}/c^2$. We observe the radiative decay mode $D_{sJ}^+(2457) \to D_s^+ \gamma$ and the dipion decay mode $D_{sJ}^+(2457) \to D_s^+ \pi^+ \pi^-$, and determine their branching fractions. No corresponding decays are observed for the $D_{sJ}(2317)$ state. These results are consistent with the spin-parity assignments of $0^+$ for the $D_{sJ}(2317)$ and $1^+$ for the $D_{sJ}(2457)$.Comment: 5 pages, 6 figures; Added content, updated and paper submitted to PR

Observation of B→K∗ℓ+ℓ−B \to K^* \ell^+ \ell^-

We report the first observation of the flavor-changing neutral current decay $B \to K^* \ell^+ \ell^-$ and an improved measurement of the decay $B \to K \ell^+ \ell^-$, where $\ell$ represents an electron or a muon, with a data sample of 140 fb${}^{-1}$ accumulated at the $\Upsilon(4S)$ resonance with the Belle detector at KEKB. The results for the branching fractions are ${\cal B}(B \to K^* \ell^+ \ell^-)=(11.5^{+2.6}_{-2.4} \pm 0.8 \pm 0.2) \times 10^{-7}$ and ${\cal B}(B \to K \ell^+ \ell^-)=(4.8^{+1.0}_{-0.9} \pm 0.3 \pm 0.1) \times 10^{-7}$, where the first error is statistical, the second is systematic and the third is from model dependence.Comment: 11 pages, 2 figures, submitted to PR

Observation of the DsJ(2317) and DsJ(2457) in B decays

We report the first observation of the B --> Dbar DsJ(2317) and B --> Dbar DsJ(2457) decays based on 123.8 10^6 BBar events collected with the Belle detector at KEKB. We observe the DsJ(2317) decay to Ds pi0 and DsJ(2457) decay to the Ds* pi0 and Ds gamma final states. We also set 90% CL upper limits for the decays DsJ(2317) --> Ds* gamma, DsJ(2457) --> Ds* gamma, DsJ(2457) --> Ds pi0 and DsJ(2457) --> Ds pi+ pi-.Comment: 6 pages, 3 figures. A few minor corrections. Replaced by version accepted to publication in Phys. Rev. Let

Evidence for B0->pi0pi0

We report evidence for the decay B0->pi0pi0. The analysis is based on a data sample of 152million BBbar pairs collected at the Upsilon(4s) resonance with the Belle detector at the KEKB e+e- storage ring. We find 25.6+9.3/-8.4(stat)+1.6/-1.4(syst) B0->pi0pi0 signal events with a significance of 3.4 standard deviations. We measure the branching fraction to be (1.7+-0.6(stat)+-0.2(syst))*10^{-6}.Comment: Submitted to PR