Nucleon-Nucleon Scattering and Effective Field Theory: Including Pions Non-perturbatively

Next to leading order effective field theory calculations are performed for ${}^1S_0$ NN scattering using subtractive renormalization procedure. One pion exchange and contact interaction potentials are iterated using Lippman-Schwinger equation. Satisfactory fit to the Nijmegen data is obtained for the momenta up to 300 MeV in the centre of mass frame. Phase shifts are also compared with the results of KSW approach where pions are included perturbatively.Comment: 7 pages, 3 figures, references added, to appear in Phys. Lett.

New bounce solutions and vacuum tunneling in de Sitter spacetime

I describe a class of oscillating bounce solutions to the Euclidean field equations for gravity coupled to a scalar field theory with multiple vacua. I discuss their implications for vacuum tunneling transitions and for elucidating the thermal nature of de Sitter spacetime.Comment: 7 pages, 3 comment

Six-dimensional Methods for Four-dimensional Conformal Field Theories

The calculation of both spinor and tensor Green's functions in four-dimensional conformally invariant field theories can be greatly simplified by six-dimensional methods. For this purpose, four-dimensional fields are constructed as projections of fields on the hypercone in six-dimensional projective space, satisfying certain transversality conditions. In this way some Green's functions in conformal field theories are shown to have structures more general than those commonly found by use of the inversion operator. These methods fit in well with the assumption of AdS/CFT duality. In particular, it is transparent that if fields on AdS$_5$ approach finite limits on the boundary of AdS$_5$, then in the conformal field theory on this boundary these limits transform with conformal dimensionality zero if they are tensors (of any rank), but with conformal dimension 1/2 if they are spinors or spinor-tensors.Comment: Version accepted for publication in Physical Review D. References to earlier work added in footnote 2. Minor errors corrected. 24 page

Massless and Massive Monopoles Carrying Nonabelian Magnetic Charges

The properties of BPS monopoles carrying nonabelian magnetic charges are investigated by following the behavior of the moduli space of solutions as the Higgs field is varied from a value giving a purely abelian symmetry breaking to one that leaves a nonabelian subgroup of the gauge symmetry unbroken. As the limit of nonabelian unbroken symmetry is reached, some of the fundamental abelian monopoles remain massive but acquire nonabelian magnetic charges. The BPS mass formula indicates that others should because massless in this limit. These do not correspond to distinct solitons, but instead are manifested as a ``nonabelian cloud'' surrounding the massive monopoles, with their position and phase degrees of freedom being transformed into parameters characterizing the cloud.Comment: 17 pages Latex, presented at Quarks-96, Yaroslavl, Russi

Current problems in the zodiacal light

Photometric observations of zodiacal ligh

A program of ground-based studies of the zodiacal light

Nonzodiacal light sources of polarization in nightglow, and polarization due to airglow line emission

Polarimetric observations of Comet Kohoutek (1973f)

Radio, optical, and visual observations were made of Comet Kohoutek (1973f) using facilities of the National Radio Astronomy Observatory (NRAO) and of the Hawaii Night Sky Observatory, State University of New York at Albany (SUNYA). Transit observations were made using the NRAO 300 ft radio telescope on six consecutive days beginning November 24, 1973. Observations were carried out in the continuum at 11 cm using the 4-feed system at different position angles. The data were recorded on magnetic tape and were computer reduced. Results were negative, with an rms error of 62 milli flux units, giving an upper limit of 180 mfu for the 11 cm continuum emission from the Comet. This relatively high detection limit resulted from a combination of interference and bad weather that affected these pre-perihelion observations. No observations could be scheduled near or after perihelion

Zodiacal light Summary report

Survey in form of tables and graphs of surface brightness and degree of polarization of zodiacal light as function of elongation in plane of elliptic - related bibliograph