Precision Measurement of sin^2 theta_W at a Reactor

This paper presents a strategy for measuring sin^2 theta_W to ~1% at a reactor-based experiment, using antineutrinos electron elastic scattering. This error is comparable to the NuTeV, SLAC E158, and APV results on sin^2 theta_W, but with substantially different contributions to the systematics. An improved method for identifying antineutrino proton events, which serve both as a background and as a normalization sample, is described. The measurement can be performed using the near detector of the presently proposed reactor-based oscillation experiments. We conclude that an absolute error of delta(sin^2 theta_W)=0.0019 may be achieved.Comment: To be Submitted to Phys. Rev.

Exploring the powering source of the TeV X-ray binary LS 5039

LS 5039 is one of the four TeV emitting X-ray binaries detected up to now. The powering source of its multi-wavelength emission can be accretion in a microquasar scenario or wind interaction in a young non-accreting pulsar scenario. These two scenarios predict different morphologic and peak position changes along the orbital cycle of 3.9 days, which can be tested at milliarcsecond scales using VLBI techniques. Here we present a campaign of 5 GHz VLBA observations conducted in June 2000 (2 runs five days apart). The results show a core component with a constant flux density, and a fast change in the morphology and the position angle of the elongated extended emission, but maintaining a stable flux density. These results are difficult to fit comfortably within a microquasar scenario, whereas they appear to be compatible with the predicted behavior for a non-accreting pulsar.Comment: 6 pages, 1 figure. Needs PoS.cls. Contributed talk at The 9th European VLBI Network Symposium on The role of VLBI in the Golden Age for Radio Astronomy and EVN Users Meeting, September 23-26, 2008, Bologna, Ital

Universal fluctuations in spectra of the lattice Dirac operator

Recently, Kalkreuter obtained the complete Dirac spectrum for an $SU(2)$ lattice gauge theory with dynamical staggered fermions on a $12^4$ lattice for $\beta =1.8$ and $\beta=2.8$. We performed a statistical analysis of his data and found that the eigenvalue correlations can be described by the Gaussian Symplectic Ensemble. In particular, long range fluctuations are strongly suppressed: the variance of a sequence of levels containing $n$ eigenvalues on average is given by $\Sigma_2(n) \sim\frac 1{2\pi^2}(\log n + {\rm const.})$ instead of $\Sigma_2(n) = n$ for a random sequence of levels. Our findings are in agreement with the anti-unitary symmetry of the lattice Dirac operator for $N_c=2$ with staggered fermions which differs from the continuuum theory. For $N_c = 3$ we predict that the eigenvalue correlations are given by the Gaussian Unitary Ensemble.Comment: 8 pages + 3 figures (will be faxed on request

Bounds on the dragging rate and on the rotational mass-energy in slowly and differentially rotating relativistic stars

For relativistic stars rotating slowly and differentially with a positive angular velocity, some properties in relation to the positiveness of the rate of rotational dragging and of the angular momentum density are derived. Also, a new proof for the bounds on the rotational mass-energy is given.Comment: 23 pages, latex. Submitted to J. Math. Phy

Quantum scalar fields in the half-line. A heat kernel/zeta function approach

In this paper we shall study vacuum fluctuations of a single scalar field with Dirichlet boundary conditions in a finite but very long line. The spectral heat kernel, the heat partition function and the spectral zeta function are calculated in terms of Riemann Theta functions, the error function, and hypergeometric PFQ functions.Comment: Latex file, 11 pages, 7 figure