V(us) and m(s) from hadronic tau decays

Recent experimental results on hadronic tau decays into strange particles by the OPAL Collaboration are employed to determine V(us) and m(s) from moments of the invariant mass distribution. Our results are V(us)=0.2208+/-0.0034 and m(s)(2 GeV)=81+/-22 MeV. The error on V(us) is dominated by experiment and should be improvable in the future. Nevertheless, already now our result is competitive with the standard extraction of V(us) from K(e3) decays, and it is compatible with unitarity.     

Time Varying Gravitational Constant G via Entropic Force

If the uncertainty principle applies to the Verlinde entropic idea, it leads to a new term in the Newton's second law of mechanics in the Planck's scale. This curious velocity dependent term inspires a frictional feature of the gravity. In this short letter we address that this new term modifies the effective mass and the Newtonian constant as the time dependentquantities. Thus we must have a running on the value of the effective mass on the particle mass m near the holographic screen and the G. This result has a nigh relation with the Dirac hypothesis about the large numbers hypothesis (L.N.H.). We propose that the corrected entropic terms via Verlinde idea can be brought as a holographic evidence for the authenticity of the Dirac idea.     

Observations of acoustic surface waves in outdoor sound propagation

Acoustic surface waves have been detected propagating outdoors under natural conditions. Two critical experimental conditions were employed to ensure the conclusive detection of these waves. First, acoustic pulses rather than a continuous wave source allowed an examination of the waveform shape and avoided the masking of wave arrivals. Second, a snow cover provided favorable ground impedance conditions for surface waves to exist. The acoustic pulses were generated by blank pistol shots fired 1 m above the snow. The resultant waveforms were measured using a vertical array of six microphones located 60 m away from the source at heights between 0.1 and 4.75 m. A strong, low frequency "tail" following the initial arrival was recorded near the snow surface. This tail, and its exponential decay with height (z) above the surface (approximately e(-alpha z)), are diagnostic features of surface waves. The measured attenuation coefficient alpha was 0.28 m(-1). The identification of the surface wave is confirmed by comparing the measured waveforms with waveforms predicted by the theoretical evaluation of the explicit surface wave pole term using residue theory.     

Strong coupling constant from the photon structure function

We extract the value of the strong coupling constant alpha(s) from a single-parameter pointlike fit to the photon structure function F(gamma)(2) at large x and Q(2) and from a first five-parameter full (pointlike and hadronic) fit to the complete F(gamma)(2)data set taken at PETRA, TRISTAN, and LEP. In next-to-leading order and the MS renormalization and factorization schemes, we obtain alpha(s)(m(Z))=0.1183+/-0.0050(expt)(+0.0029)(-0.0028)(theor) (pointlike) and alpha(s)(m(Z))=0.1198+/-0.0028(expt)(+0.0034)(-0.0046)(theor) (pointlike and hadronic). We demonstrate that the data taken at LEP have reduced the experimental error by about a factor of 2, so that a competitive determination of alpha(s) from F(gamma)(2) is now possible.     

Nonrelativistic QED approach to the bound-electron g factor

Within a systematic approach based on nonrelativistic quantum electrodynamics, we derive the one-loop self-energy correction of order alpha(Z alpha)(4) to the bound-electron g factor. In combination with numerical data, this analytic result improves theoretical predictions for the self-energy correction for carbon and oxygen by an order of magnitude. Basing on one-loop calculations, we obtain the logarithmic two-loop contribution of order alpha(2)(Z alpha)(4)ln([(Z alpha)(-2)] and the dominant part of the corresponding constant term. The results obtained improve the accuracy of the theoretical predictions for the 1S bound-electron g factor and influence the value of the electron mass determined from g-factor measurements.     

Non-zero masses of π, K, η and κ mesons and algebraic realization of SU(3) × SU(3) chiral symmetry

An algebraic realization of SU(3) × SU(3) symmetry, with linearization on the SU(2) × Y subgroup taking into account masses of π, K, η mesons in virtual states is investigated. This is achieved by explicit breaking of the symmetry. The chosen form of the breaking term in the Lagrangian enables us to estimate the parameter c appearing in the squared mass operator. The obtained value of c(c ≈ ?1.17) is very close to that predicted by Gell-Mann, Oakes and Renner.     

Analysis of inelastic x-ray scattering spectra of low-temperature water

We analyze a set of high-resolution inelastic x-ray scattering (IXS) spectra from H2O measured at T=259, 273, and 294 K using two different phenomenological models. Model I, called the "dynamic cage model," combines the short time in-cage dynamics described by a generalized Enskog kinetic theory with a long-time cage relaxation dynamics described by an alpha relaxation. This model is appropriate for supercooled water where the cage effect is dominant and the existence of an alpha relaxation is evident from molecular-dynamics (MD) simulation data of extended simple point charge (SPC/E) model water. Model II is essentially a generalized hydrodynamic theory called the "three effective eigenmode theory" by de Schepper et al. 11. This model is appropriate for normal liquid water where the cage effect is less prominent and there is no evidence of the alpha relaxation from the MD data. We use the model I to analyze IXS data at T=259 K (supercooled water). We successfully extract the Debye-Waller factor, the cage relaxation time from the long-time dynamics, and the dispersion relation of high-frequency sound from the short time dynamics. We then use the model II to analyze IXS data at all three temperatures, from which we are able to extract the relaxation rate of the central mode and the damping of the sound mode as well as the dispersion relation for the high-frequency sound. It turns out that the dispersion relations extracted from the two models at their respective temperatures agree with each other giving the high-frequency sound speed of 2900+/-300 m/s. This is to be compared with a slightly higher value reported previously, 3200+/-320 m/s, by analyzing similar IXS data with a phenomenological-damped harmonic oscillator model 22. This latter model has traditionally been used exclusively for the analysis of inelastic scattering spectra of water. The k-dependent sound damping and central mode relaxation rate extracted from our model analyses are compared with the known values in the hydrodynamic limit.     

Anwendung des Paarmodells auf das kernphysikalische Fünfkörperproblem

The nuclear Five-body-problem ist treated as a stationary state on the basis of the Independent Pair Model. Square well potentials with hard core, Serber exchange character and averaged over spin-dependence are used so that the two-particle equations (Bethe-Goldstone-equations) can be solved analytically. The calculated binding energy (?25,98 MeV) is quite close to the weighted mean value of the measuredj=3/2 andj=1/2 resonances of nucleon-α-scattering (?24 Mev). Ther. m. s. radius of the α-core is about 35% greater than in Helium 4 which shows a moderately strong polarization of the α-core by the presence of the p-nucleon. This value is also very close to the radius of the Litium 6-α-core obtained by fitting the experimental charge distribution.     

New value of m(mu)/m(e) from muonium hyperfine splitting

The complete contribution to the muonium hyperfine splitting of relative order alpha(3)(m(e)/m(mu))lnalpha is calculated. The result is much smaller than suggested by a previous estimate and leads to a 2sigma upward shift of the most precise value for the muon-electron mass ratio. Analogous contributions are calculated for the positronium hyperfine splitting, where a discrepancy with experiment remains.     

Two-photon spectroscopy of antiprotonic helium

The precision of laser spectroscopy of antiprotonic helium (a helium atom with one of its electrons replaced by an antiproton) has improved by almost 4 orders of magnitude over its 20 years of history. Experimental transition frequencies can be compared to 3-body QED calculations to derive the antiproton-electron mass ratio. In the latest measurements of the Asacusa experiment at CERN, two-photon transitions of antiprotonic helium were excited using two counter-propagating laser beams. This method reduces the Doppler-broadening caused by the thermal motion of the atoms, and allowed us to measure the transition frequencies with a fractional precision of 2.5–5 parts in 10⁹. From these frequencies, we derived an antiproton-electron mass ratio of 1836.1526736(23). Our precision approaches that of the experimental value of the proton-electron mass ratio, and agrees with the latter within errors. Assuming CPT symmetry (i.e. \(m_{p}=m_{\overline {p}}\) ), we further derived the electron’s atomic mass as m _e = 0.0005485799091(7)u from the more accurately known atomic mass of the proton.     

Propagation Effects on the Breakdown of a Linear Amplifier Model: Complex-Mass Schrödinger Equation Driven by the Square of a Gaussian Field

Solutions to the equation are investigated, where S(x, t) is a complex Gaussian field with zero mean and specified covariance, and m≠0 is a complex mass with Im(m) ≥ 0. For real m this equation describes the backscattering of a smoothed laser beam by an optically active medium. Assuming that S(x, t) is the sum of a finite number of independent complex Gaussian random variables, we obtain an expression for the value of λ at which the q ^th moment of w.r.t. the Gaussian field S diverges. This value is found to be less or equal for all m ≠ 0, Im(m) ≥ 0 and |m|<+∞ than for |m| = +∞, i.e. when the term is absent. Our solution is based on a distributional formulation of the Feynman path-integral and the Paley-Wiener theorem. An erratum to this article is available at .     

Dependence of electroweak parameters on the definition of the top-quark mass

The QCD corrections to electroweak parameters depend on the renormalization scheme and scales used to define the top-quark mass. We analyze these dependences for theW-boson mass predicted via Δr to ${\mathcal{O}}(\alpha \alpha _s )$ and ${\mathcal{O}}(\alpha \alpha _s^2 )$ in the on-shell and $\overline {MS} $ schemes. These variations provide us with a hint on the magnitude of the unknown higher-order QCD effects and contribute to the theoretical error of the prediction.     

Precise measurements of bulk-wave ultrasonic velocity dispersion and attenuation in solid materials in the VHF range

A general method was established for precisely measuring velocity dispersion and attenuation in solid specimens with acoustic losses in the very high frequency (VHF) range, using the complex-mode measurement method and the diffraction correction method. Experimental procedures were presented for implementing such a method and demonstrated this measurement method in the frequency range of 50-230 MHz, using borosilicate glass (C-7740) as a dispersive specimen and synthetic silica glass (C-7980) as a nondispersive standard specimen. C-7980 exhibited no velocity dispersion; velocity was constant at 5929.14 +/- 0.03 m/s. C-7740 exhibited velocity dispersion, from 5542.27 m/s at 50 MHz to 5544.47 m/s at 230 MHz with an increase of about 2 m/s in the measured frequency range. When frequency dependence of attenuation was expressed as alpha = alpha(0)f(beta), the results were as follows: alpha0 = 1.07 x 10(-16) s2/m and beta = 2 for C-7980 and alpha0 = 5.16 x 10(-9) s(1.25)/m and beta = 1.25 for C-7740.     

Spin mass of an electron liquid

We show that in order to calculate correctly the spin current carried by a quasiparticle in an electron liquid one must use an effective "spin mass" m(s) that is larger than both the band mass m(b), which determines the charge current, and the quasiparticle effective mass m(*), which determines the heat capacity. We present two independent estimates of the spin mass enhancement, m(s)/m(b), in two- and three-dimensional electron liquids, based on (i) previously calculated values of the Landau parameters and (ii) a recent theory of the dynamical local field factor in the spin channel. Both methods yield a significant spin mass enhancement, which is larger in two dimensions than in three.     

Relativistic mass distribution in event-anti-event system and “realistic” equation of state for hot hadronic matter

We find the equation of state p, T ⁶,which gives the value of the sound velocity c ²7 = 0.20,in agreement with the realistic equation of state for hot hadronic matter suggested by Shuryak, in the framework of a covariant relativistic statistical mechanics of an event-anti-event system with small chemical and mass potentials. The relativistic mass distribution for such a system is obtained and shown to be a good candidate for fitting hadronic resonances, in agreement with the phenomenological models of Hagedorn, Shuryak, et al. This distribution provides a correction to the value of specific heat 3/2,of the order of 5.5%,at low temperatures.     

Stable exponential cosmological solutions with two factor spaces in the Einstein–Gauss–Bonnet model with a $$\Lambda $$-term

We study D-dimensional Einstein–Gauss–Bonnet gravitational model including the Gauss–Bonnet term and the cosmological term \(\Lambda \). We find a class of solutions with exponential time dependence of two scale factors, governed by two Hubble-like parameters \(H >0\) and h, corresponding to factor spaces of dimensions \(m >2\) and \(l > 2\), respectively. These solutions contain a fine-tuned \(\Lambda = \Lambda (x, m, l, \alpha )\), which depends upon the ratio \(h/H = x\), dimensions of factor spaces m and l, and the ratio \(\alpha = \alpha _2/\alpha _1\) of two constants (\(\alpha _2\) and \(\alpha _1\)) of the model. The master equation \(\Lambda (x, m, l,\alpha ) = \Lambda \) is equivalent to a polynomial equation of either fourth or third order and may be solved in radicals. The explicit solution for \(m = l\) is presented in “Appendix”. Imposing certain restrictions on x, we prove the stability of the solutions in a class of cosmological solutions with diagonal metrics. We also consider a subclass of solutions with small enough variation of the effective gravitational constant G and show the stability of all solutions from this subclass.     

Heavy fermion fluid in high magnetic fields: an infrared study of CeRu4Sb12

We report a comprehensive infrared magnetospectroscopy study of a CeRu4Sb12 compound revealing quasiparticles with a heavy effective mass m*, with a detailed analysis of optical constants in fields up to 17 T. We find that the applied magnetic field strongly affects the low-energy excitations in the system. In particular, the magnitude of m* approximately = 70 m(b) (m(b) is the quasiparticle band mass) at 10 K is suppressed by as much as 25% at 17 T. This effect is in quantitative agreement with the mean-field solution of the periodic Anderson model augmented with a Zeeman term.     

Charged particle induced ternary fission

Ternary fission has been investigated by irradiating a natural uranium target with 13.5 MeV deuterons. The energy and angular distributions of ternary alpha particles do not differ from those observed in spontaneous or thermal neutron induced fission. The angle between alpha particles and light fragments has a most probable value of \(\bar \vartheta _{\ell f - \alpha } = 82.1 \circ \pm 0.6 \circ \) with a dispersion (FWHM) of \(\Delta \vartheta = 18.4 \circ \pm 1.2 \circ \) . The corresponding values of the energy distribution are \(\bar E\alpha \) =(14.8 ±0.5)MeV and ΔE(FWHM)= (9.1±1.1)MeV. The peak-to-valley ratio of the ternary fission fragment mass distribution is found to increase with increasing alpha energy. For near-symmetric mass division a strong broadening of the angular distribution is observed.     

Low-Frequency Pulsations of Coronal Magnetic Loops

We analyze low-frequency intensity fluctuations of the microwave emission from solar flares at frequencies 22 and 37 GHz. The three microwave bursts of durations of about 1 h, observed at the Metsähovi Radio Observatory (Finland) with the time resolution of 0.1 and 0.05 s, are studied. To obtain spectral-temporal characteristics of the low-frequency fluctuations, we apply the Wigner-Ville method, i.e., the time-lag Fourier transform of the local autocorrelation function of an analytical signal. As a result, we obtain for the first time the dynamical spectra of the low-frequency fluctuations, which are identified as MHD eigenoscillations of coronal magnetic loops. The features of the dynamical spectra testify that several types of low-frequency pulsations are excited in coronal magnetic loops during solar flares: 1) Fast and slow magnetosonic oscillations with periods of 1-1.5 s and 200-280 s, respectively. Fast magnetosonic oscillations appear as pulse trains of duration 100-200 s and have the positive frequency drift d/ dt 0.125 Hz/min and the frequency splitting 0.05 Hz; 2) The eigenoscillations of a coronal magnetic loop as an equivalent electric circuit. The period of these oscillations is about 1 s during the initial stage of a microwave burst and increases gradually up to 4 s during the decay stage of the radio emission; and 3) Intensity modulation of the microwave radiation by a periodic pulse sequence with a period of about 1 s at the burst onset and about 2 s at its end. The parameters of the dynamical spectra and identification of the MHD pulsations allow us to obtain information on the loop parameters, such as the ratio of the loop radius to its length (r/L 0.1), the ratio of the gas pressure to the magnetic-field pressure inside the loop ( 3· 10^-3), the ratio of plasma densities outside and inside the loop, and the electric current in the coronal loop (I 1.5 · 10¹² A).