Problems of the rotating-torsion-balance limit on the photon mass

We discuss the problems (and the promise) of the ingenious method introduced by Lakes, and recently improved on by Luo, to detect a possible small photon mass $\mu$ by measuring the ambient magnetic vector potential from large scale magnetic fields. We also point out how an improved ``indirect'' limit can be obtained using modern measurements of astrophysical magnetic fields and plasmas and that a good ``direct'' limit exists using properties of the solar wind.Comment: 4 pages, revised title and content

s-wave scattering and the zero-range limit of the finite square well in arbitrary dimensions

We examine the zero-range limit of the finite square well in arbitrary dimensions through a systematic analysis of the reduced, s-wave two-body time-independent Schr\"odinger equation. A natural consequence of our investigation is the requirement of a delta-function multiplied by a regularization operator to model the zero-range limit of the finite-square well when the dimensionality is greater than one. The case of two dimensions turns out to be surprisingly subtle, and needs to be treated separately from all other dimensions

Shape invariance approach to exact solutions of the Klein-Gordon equation

Using the shape invariance property we obtain exact solutions of the (1+1)dimensional Klein-Gordon equation for certain types of scalar and vector potentials. We also discuss the possibility of obtaining real energy spectrum with non-Hermitian interaction within this framework

An Anomalous UV Extension in NGC6251

Deep U-band FOC images of the nuclear region of NGC6251 have revealed a region of extended emission which is most probably radiation scattered from a continuum source in the nucleus. This radiation lies interior to a dust ring, is nearly perpendicular to the radio jet axis, and is seen primarily in the FOC U and b filters. The extension has a low observed polarization($\le 10$), and is unlikely to arise from line emission. We know of no other examples similar to what we have found in NGC 6251, and we offer some tentative explanations. The nuclear morphology shows clear similarities to that seen in the nucleus of NGC 4261 except for the extended U-band radiation.Comment: 14 pages AAStex format + 4 figures; accepted for publication in ApJ Letter

Pioneer 10 Doppler data analysis: disentangling periodic and secular anomalies

This paper reports the results of an analysis of the Doppler tracking data of Pioneer probes which did show an anomalous behaviour. A software has been developed for the sake of performing a data analysis as independent as possible from that of J. Anderson et al. \citep{anderson}, using the same data set. A first output of this new analysis is a confirmation of the existence of a secular anomaly with an amplitude about 0.8 nms$^{-2}$ compatible with that reported by Anderson et al. A second output is the study of periodic variations of the anomaly, which we characterize as functions of the azimuthal angle $\varphi$ defined by the directions Sun-Earth Antenna and Sun-Pioneer. An improved fit is obtained with periodic variations written as the sum of a secular acceleration and two sinusoids of the angles $\varphi$ and $2\varphi$. The tests which have been performed for assessing the robustness of these results are presented.Comment: 13 pages, 6 figures, minor amendment

Self-Dual Conformal Supergravity and the Hamiltonian Formulation

In terms of Dirac matrices the self-dual and anti-self-dual decomposition of a conformal supergravity is given and a self-dual conformal supergravity theory is developed as a connection dynamic theory in which the basic dynamic variabes include the self-dual spin connection i.e. the Ashtekar connection rather than the triad. The Hamiltonian formulation and the constraints are obtained by using the Dirac-Bergmann algorithm. PACS numbers: 04.20.Cv, 04.20.Fy,04.65.+

Superfield Description of a Self-Dual Supergravity a la MacDowell-Mansouri

Using MacDowell-Mansouri theory, in this work, we investigate a superfield description of the self-dual supergravity a la Ashtekar. We find that in order to reproduce previous results on supersymmetric Ashtekar formalism, it is necessary to properly combine the supersymmetric field-strength in the Lagrangian. We extend our procedure to the case of supersymmetric Ashtekar formalism in eight dimensions.Comment: 19 pages, Latex; section 6 improve