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

Spontaneous waves in muscle fibres

Mechanical oscillations are important for many cellular processes, e.g. the beating of cilia and flagella or the sensation of sound by hair cells. These dynamic states originate from spontaneous oscillations of molecular motors. A particularly clear example of such oscillations has been observed in muscle fibers under non-physiological conditions. In that case, motor oscillations lead to contraction waves along the fiber. By a macroscopic analysis of muscle fiber dynamics we find that the spontaneous waves involve non-hydrodynamic modes. A simple microscopic model of sarcomere dynamics highlights mechanical aspects of the motor dynamics and fits with the experimental observations.Comment: 14 pages, 9 figure

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

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

Observation of Large CP Violation and Evidence for Direct CP Violation in B0-->pi+pi- Decays

We report the first observation of CP-violating asymmetries in B0 --> pi+pi- decays based on a 140 fb-1 data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. We reconstruct one neutral B meson as a B0 --> pi+pi- CP eigenstate and identify the flavor of the accompanying B meson from its decay products. We apply an unbinned maximum likelihood fit to the distribution of the time intervals between the two B meson decay points. The fit yields the CP-violating asymmetry amplitudes Apipi = +0.58+/-0.15(stat)+/-0.07(syst) and Spipi = -1.00+/-0.21(stat)+/-0.07(syst). We rule out the CP-conserving case, Apipi=Spipi=0, at a level of 5.2 standard deviations. We also find evidence for direct CP violation with a significance at or greater than 3.2 standard deviations for any Spipi value.Comment: 9 pages, 3 figure

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 a narrow charmonium-like state in exclusive B+ -> K+ pi+pi- J/psi decays

We report the observation of a narrow charmonium-like state produced in the exclusive decay process B+ -> K+ pi+pi- J/psi. This state, which decays into pi+pi- J/psi, has a mass of 3872.0+-0.6(stat)+-0.5(syst) MeV, a value that is very near the M_D + M_D* mass threshold. The results are based on an analysis of 152M B-Bbar events collected at the Upsilon(4S) resonance in the Belle detector at the KEKB collider. The statistical significance of the signal is in excess of 10 sigma.Comment: 10 pages 4 figures, submitted to Physical Review Letter

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

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