9,991 research outputs found
Understanding Supernova Neutrino Physics using Low-Energy Beta-Beams
We show that fitting linear combinations of low-energy beta-beam spectra to
supernova-neutrino energy-distributions reconstructs the response of a nuclear
target to a supernova flux in a very accurate way. This allows one to make
direct predictions about the supernova-neutrino signal in a terrestrial
neutrino detector.Comment: To appear in the proceedings of International School of Nuclear
Physics: 27th Course: "Neutrinos in Cosmology, in Astro, Particle and Nuclear
Physics". Erice, Sicily, Italy, 16-2
Reconstructing supernova-neutrino spectra using low-energy beta-beams
Only weakly interacting, neutrinos are the principal messengers reaching us
from the center of a supernova. Terrestrial neutrino telescopes, such as SNO
and SuperKamiokande, can provide precious information about the processes in
the core of a collapsing and exploding star. But the information about the
supernova that a neutrino detector can supply, is restricted by the fact that
little experimental data on the neutrino-nucleus cross sections exists and by
the uncertainties in theoretical calculations. In this letter, we propose a
novel procedure that determines the response of a target nucleus in a
supernova-neutrino detector directly, by using low-energy beta-beams. We show
that fitting 'synthetic' spectra, constructed by taking linear combinations of
beta-beam spectra, to the original supernova-neutrino spectra reproduces the
folded differential cross sections very accurately. Comparing the response in a
terrestrial detector to these synthetic responses provides a direct way to
determine the main parameters of the supernova-neutrino energy-distribution.Comment: 4 page
Untangling supernova-neutrino oscillations with beta-beam data
Recently, we suggested that low-energy beta-beam neutrinos can be very useful
for the study of supernova neutrino interactions. In this paper, we examine the
use of a such experiment for the analysis of a supernova neutrino signal. Since
supernova neutrinos are oscillating, it is very likely that the terrestrial
spectrum of supernova neutrinos of a given flavor will not be the same as the
energy distribution with which these neutrinos were first emitted. We
demonstrate the efficacy of the proposed method for untangling multiple
neutrino spectra. This is an essential feature of any model aiming at gaining
information about the supernova mechanism, probing proto-neutron star physics,
and understanding supernova nucleosynthesis, such as the neutrino process and
the r-process. We also consider the efficacy of different experimental
approaches including measurements at multiple beam energies and detector
configurations.Comment: 13 pages, 11 figures, accepted for publication in Phys. Rev.
Asymptotics of the partition function for random matrices via Riemann-Hilbert techniques, and applications to graphical enumeration
We study the partition function from random matrix theory using a well known
connection to orthogonal polynomials, and a recently developed Riemann-Hilbert
approach to the computation of detailed asymptotics for these orthogonal
polynomials. We obtain the first proof of a complete large N expansion for the
partition function, for a general class of probability measures on matrices,
originally conjectured by Bessis, Itzykson, and Zuber. We prove that the
coefficients in the asymptotic expansion are analytic functions of parameters
in the original probability measure, and that they are generating functions for
the enumeration of labelled maps according to genus and valence. Central to the
analysis is a large N expansion for the mean density of eigenvalues, uniformly
valid on the entire real axis.Comment: 44 pages, 4 figures. To appear, International Mathematics Research
Notice
Meeting update: faecal microbiota transplantation––bench, bedside, courtroom?
A group of stakeholders met, under the aegis of the British Society of Gastroenterology, to discuss the current landscape of faecal microbiota transplant- ation (FMT) within the UK and beyond. The meeting covered a wide range of topics, ranging from the practical aspects of establishing an FMT service and regu- latory issues relating to its delivery, to research implications and likely future directions
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