52,487 research outputs found
Determining the Supernova Direction by its Neutrinos
Supernova neutrinos, which arrive at Earth earlier than light, allow for the
earliest determination of the direction of the supernova. The topic of this
paper is to study how accurately we can determine the supernova direction. We
simulate supernova neutrino events at the SuperKamiokande detector, using a
realistic supernova model and several realistic neutrino oscillation models.
With the results of our simulation, we can restrict the supernova direction to
be within a circle of radius . In several neutrino oscillation models,
this accuracy is increased to . We also discuss the influence of an
accident that occurred at the SuperKamiokande detector. After repair of the
detector, using the remaining PMTs, the accuracy becomes about for
no oscillation.Comment: 20 pages, 8 figures, Prog. Theor. Phys., accepte
Phase Diagram of Gross-Neveu Model at Finite Temperature, Density and Constant Curvature
We discuss a phase structure of chiral symmetry breaking in the Gross-Neveu
model at finite temperature, density and constant curvature. The effective
potential is evaluated in the leading order of the -expansion and in a
weak curvature approximation. The third order critical line is found on the
critical surface in the parameter space of temperature, chemical potential and
constant curvature.Comment: 11 pages, Latex. 3 figures (eps files
Intersecting D-brane states derived from the KP theory
A general scheme to find tachyon boundary states is developed within the
framework of the theory of KP hierarchy. The method is applied to calculate
correlation function of intersecting D-branes and rederived the results of our
previous works as special examples. A matrix generalization of this scheme
provides a method to study dynamics of coincident multi D-branes.Comment: 10 page
Pion Production Model - Connection between Dynamics and Quark Models
We discuss the difficulties in testing the hadron models by using the N^*
parameters extracted from the empirical amplitude analyses of the pi-N and
gamma-N reaction data. As an alternative or perhaps a more advantageous
approach, we present a Hamiltonian formulation that can relate the pion
production dynamics and the constituent quark models of N^* structure. The
application of the approach in investigating the Delta and N^*(S_{11})
excitations is reviewed. It is found that while the Delta excitation can be
described satisfactory, the pi-N scattering in S_{11} channel can not be
described by the constituent quark models based on either the
one-gluon-exchange or one-meson-exchange mechanisms. A phenomenological
quark-quark potential has been constructed to reproduce the S_{11} amplitude.Comment: 11 pages, 4 figures, to be published in Proceedings of NSTAR2000
workshop held at Jefferson Laboratory, Feb., 200
Point interactions in one dimension and holonomic quantum fields
We introduce and study a family of quantum fields, associated to
delta-interactions in one dimension. These fields are analogous to holonomic
quantum fields of M. Sato, T. Miwa and M. Jimbo. Corresponding field operators
belong to an infinite-dimensional representation of the group SL(2,\Rb) in
the Fock space of ordinary harmonic oscillator. We compute form factors of such
fields and their correlation functions, which are related to the determinants
of Schroedinger operators with a finite number of point interactions. It is
also shown that these determinants coincide with tau functions, obtained
through the trivialization of the -bundle over a Grassmannian
associated to a family of Schroedinger operators.Comment: 17 page
- âŠ