3,076 research outputs found
New Test of Supernova Electron Neutrino Emission using Sudbury Neutrino Observatory Sensitivity to the Diffuse Supernova Neutrino Background
Supernovae are rare nearby, but they are not rare in the Universe, and all
past core-collapse supernovae contributed to the Diffuse Supernova Neutrino
Background (DSNB), for which the near-term detection prospects are very good.
The Super-Kamiokande limit on the DSNB electron {\it antineutrino} flux,
cm s, is just above the
range of recent theoretical predictions based on the measured star formation
rate history. We show that the Sudbury Neutrino Observatory should be able to
test the corresponding DSNB electron {\it neutrino} flux with a sensitivity as
low as cm s,
improving the existing Mont Blanc limit by about three orders of magnitude.
While conventional supernova models predict comparable electron neutrino and
antineutrino fluxes, it is often considered that the first (and
forward-directed) SN 1987A event in the Kamiokande-II detector should be
attributed to electron-neutrino scattering with an electron, which would
require a substantially enhanced electron neutrino flux. We show that with the
required enhancements in either the burst or thermal phase fluxes, the
DSNB electron neutrino flux would generally be detectable in the Sudbury
Neutrino Observatory. A direct experimental test could then resolve one of the
enduring mysteries of SN 1987A: whether the first Kamiokande-II event reveals a
serious misunderstanding of supernova physics, or was simply an unlikely
statistical fluctuation. Thus the electron neutrino sensitivity of the Sudbury
Neutrino Observatory is an important complement to the electron antineutrino
sensitivity of Super-Kamiokande in the quest to understand the DSNB.Comment: 10 pages, 3 figure
On dynamical adjoint functor
We give an explicit formula relating the dynamical adjoint functor and
dynamical twist over nonalbelian base to the invariant pairing on parabolic
Verma modules. As an illustration, we give explicit - and
-invariant star product on projective spaces
Tentative Detection of the Nitrosylium Ion in Space
We report the tentative detection in space of the nitrosylium ion, NO.
The observations were performed towards the cold dense core Barnard 1-b. The
identification of the NO =2--1 line is supported by new laboratory
measurements of NO rotational lines up to the =8--7 transition
(953207.189\,MHz), which leads to an improved set of molecular constants: \,MHz, \,kHz, and \,MHz. The profile of the feature assigned to NO exhibits two
velocity components at 6.5 and 7.5 km s, with column densities of and cm, respectively. New
observations of NO and HNO, also reported here, allow to estimate the following
abundance ratios: (NO)/(NO), and
(HNO)/(NO). This latter value provides important constraints
on the formation and destruction processes of HNO. The chemistry of NO and
other related nitrogen-bearing species is investigated by the means of a
time-dependent gas phase model which includes an updated chemical network
according to recent experimental studies. The predicted abundance for NO
and NO is found to be consistent with the observations. However, that of HNO
relative to NO is too high. No satisfactory chemical paths have been found to
explain the observed low abundance of HNO. HSCN and HNCS are also reported here
with an abundance ratio of . Finally, we have searched for NNO,
NO, HNNO, and NNOH, but only upper limits have been obtained for
their column density, except for the latter for which we report a tentative
3- detection.Comment: To appear in the Astrophysical Journal October 20, 201
One-dimensional Chern-Simons theory
We study a one-dimensional toy version of the Chern-Simons theory. We
construct its simplicial version which comprises features of a low-energy
effective gauge theory and of a topological quantum field theory in the sense
of Atiyah.Comment: 37 page
Dynamical boundary conditions for integrable lattices
Some special solutions to the reflection equation are considered. These
boundary matrices are defined on the common quantum space with the other
operators in the chain. The relations with the Drinfeld twist are discussed.Comment: LaTeX, 12page
Physical phase space of lattice Yang-Mills theory and the moduli space of flat connections on a Riemann surface
It is shown that the physical phase space of \g-deformed Hamiltonian
lattice Yang-Mills theory, which was recently proposed in refs.[1,2], coincides
as a Poisson manifold with the moduli space of flat connections on a Riemann
surface with handles and therefore with the physical phase space of
the corresponding -dimensional Chern-Simons model, where and are
correspondingly a total number of links and vertices of the lattice. The
deformation parameter \g is identified with and is an
integer entering the Chern-Simons action.Comment: 12 pages, latex, no figure
Muon-Induced Background Study for an Argon-Based Long Baseline Neutrino Experiment
We evaluated rates of transversing muons, muon-induced fast neutrons, and
production of Cl and other cosmogenically produced nuclei that pose as
potential sources of background to the physics program proposed for an
argon-based long baseline neutrino experiment at the Sanford Underground
Research Facility (SURF). The Geant4 simulations were carried out with muons
and muon-induced neutrons for both 800 ft (0.712 km.w.e.) and 4850 ft levels
(4.3 km.w.e.). We developed analytic models to independently calculate the
Cl production using the measured muon fluxes at different levels of the
Homestake mine. The muon induced Cl production rates through stopped
muon capture and the muon-induced neutrons and protons via (n,p) and (p,n)
reactions were evaluated. We find that the Monte Carlo simulated production
rates of Cl agree well with the predictions from analytic models. A
depth-dependent parametrization was developed and benchmarked to the direct
analytic models. We conclude that the muon-induced processes will result in
large backgrounds to the physics proposed for an argon-based long baseline
neutrino experiment at a depth of less than 4.0 km.w.e.Comment: 12 pages, 15 figure
Nature of the light scalar mesons
Despite the apparent simplicity of meson spectroscopy, light scalar mesons
cannot be accommodated in the usual structure. We study the
description of the scalar mesons below 2 GeV in terms of the mixing of a chiral
nonet of tetraquarks with conventional states. A strong
diquark-antidiquark component is found for several states. The consideration of
a glueball as dictated by quenched lattice QCD drives a coherent picture of the
isoscalar mesons.Comment: 14 pages, 1 figure, accepted for publication in Phys. Rev.
Grafting and Poisson structure in (2+1)-gravity with vanishing cosmological constant
We relate the geometrical construction of (2+1)-spacetimes via grafting to
phase space and Poisson structure in the Chern-Simons formulation of
(2+1)-dimensional gravity with vanishing cosmological constant on manifolds of
topology , where is an orientable two-surface of genus
. We show how grafting along simple closed geodesics \lambda is
implemented in the Chern-Simons formalism and derive explicit expressions for
its action on the holonomies of general closed curves on S_g. We prove that
this action is generated via the Poisson bracket by a gauge invariant
observable associated to the holonomy of . We deduce a symmetry
relation between the Poisson brackets of observables associated to the Lorentz
and translational components of the holonomies of general closed curves on S_g
and discuss its physical interpretation. Finally, we relate the action of
grafting on the phase space to the action of Dehn twists and show that grafting
can be viewed as a Dehn twist with a formal parameter satisfying
.Comment: 43 pages, 10 .eps figures; minor modifications: 2 figures added,
explanations added, typos correcte
Hamiltonian Reduction and the Construction of q-Deformed Extensions of the Virasoro Algebra
In this paper we employ the construction of Dirac bracket for the remaining
current of deformed Kac-Moody algebra when constraints similar to
those connecting the -WZW model and the Liouville theory are imposed and
show that it satisfy the q-Virasoro algebra proposed by Frenkel and
Reshetikhin. The crucial assumption considered in our calculation is the
existence of a classical Poisson bracket algebra induced, in a consistent
manner by the correspondence principle, mapping the quantum generators into
commuting objects of classical nature preserving their algebra.Comment: 6 pages, late
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