3,937 research outputs found
A road map to solar neutrino fluxes, neutrino oscillation parameters, and tests for new physics
We analyze all available solar and related reactor neutrino experiments, as
well as simulated future 7Be, p-p, pep, and ^8B solar neutrino experiments. We
treat all solar neutrino fluxes as free parameters subject to the condition
that the total luminosity represented by the neutrinos equals the observed
solar luminosity (the `luminosity constraint'). Existing experiments show that
the p-p solar neutrino flux is 1.02 +- 0.02 (1 sigma) times the flux predicted
by the BP00 standard solar model; the 7Be neutrino flux is 0.93^{+0.25}_{-0.63}
the predicted flux; and the ^8B flux is 1.01 +- 0.04 the predicted flux. The
neutrino oscillation parameters are: Delta m^2 = 7.3^{+0.4}_{-0.6}\times
10^{-5} eV^2 and tan^2 theta_{12} = 0.41 +- 0.04. We evaluate how accurate
future experiments must be to determine more precisely neutrino oscillation
parameters and solar neutrino fluxes, and to elucidate the transition from
vacuum-dominated to matter-dominated oscillations at low energies. A future 7Be
nu-e scattering experiment accurate to +- 10 % can reduce the uncertainty in
the experimentally determined 7Be neutrino flux by a factor of four and the
uncertainty in the p-p neutrino flux by a factor of 2.5 (to +- 0.8 %). A future
p-p experiment must be accurate to better than +- 3 % to shrink the uncertainty
in tan^2 theta_{12} by more than 15 %. The idea that the Sun shines because of
nuclear fusion reactions can be tested accurately by comparing the observed
photon luminosity of the Sun with the luminosity inferred from measurements of
solar neutrino fluxes. Based upon quantitative analyses of present and
simulated future experiments, we answer the question: Why perform low-energy
solar neutrino experiments?Comment: Updated all calculations to include SNO salt-phase data and improved
GNO and SAGE data, all released September 7, 2003 at TAUP03. Updating
produces only minor numerical changes. Accepted for publication in JHE
Global Analysis of Solar Neutrino Oscillations Including SNO CC Measurement
For active and sterile neutrinos, we present the globally allowed solutions
for two neutrino oscillations. We include the SNO CC measurement and all other
relevant solar neutrino and reactor data. Five active neutrino oscillation
solutions (LMA, LOW, SMA, VAC, and Just So2) are currently allowed at 3 sigma;
three sterile neutrino solutions (Just So2, SMA, and VAC) are allowed at 3
sigma. The goodness of fit is satisfactory for all eight solutions. We also
investigate the robustness of the allowed solutions by carrying out global
analyses with and without: 1) imposing solar model constraints on the 8B
neutrino flux, 2) including the Super-Kamiokande spectral energy distribution
and day-night data, 3) including a continuous mixture of active and sterile
neutrinos, 4) using an enhanced CC cross section for deuterium (due to
radiative corrections), and 5) a optimistic, hypothetical reduction by a factor
of three of the error of the SNO CC rate. For every analysis strategy used in
this paper, the most favored solutions all involve large mixing angles: LMA,
LOW, or VAC. The favored solutions are robust, but the presence at 3 sigma of
individual sterile solutions and the active Just So2 solution is sensitive to
the analysis assumptions.Comment: 9 figures, higher resolution versions at http://www.sns.ias.edu/~jnb,
added references and clarification
Solar Neutrinos Before and After Neutrino 2004
We compare, using a three neutrino analysis, the allowed neutrino oscillation
parameters and solar neutrino fluxes determined by the experimental data
available Before and After Neutrino 2004. New data available after Neutrino2004
include refined KamLAND and gallium measurements. We use six different
approaches to analyzing the KamLAND data. We present detailed results using all
the available neutrino and anti-neutrino data for Delta m^2_{12}, tan^2
theta_{12}, sin^2 theta_{13}, and sin^2 eta (sterile fraction). Using the same
complete data sets, we also present Before and After determinations of all the
solar neutrino fluxes, which are treated as free parameters, an upper limit to
the luminosity fraction associated with CNO neutrinos, and the predicted rate
for a 7Be solar neutrino experiment. The 1 sigma (3 sigma) allowed range of
Delta m^2_{21} = (8.2 +- 0.3) (^+1.0_-0.8)times 10^{-5} eV^2 is decreased by a
factor of 1.7 (5), but the allowed ranges of all other neutrino oscillation
parameters and neutrino fluxes are not significantly changed. Maximal mixing is
disfavored at 5.8 sigma and the bound on the mixing angle theta_{13} is
slightly improved to sin^2 theta_{13}<0.048 at 3 sigma. The predicted rate in a
7Be neutrino-electron scattering experiment is (0.665 +-0.015) of the rate
implied by the BP04 solar model in the absence of neutrino oscillations. The
corresponding predictions for p-p and pep experiments are, respectively, 0.707
{+0.011}{-0.013} and 0.644 {+0.011}{-0.013}. We derive upper limits to CPT
violation in the weak sector by comparing reactor anti-neutrino oscillation
parameters with neutrino oscillation parameters. We also show that the recent
data disfavor at 91 % CL a proposed non-standard interaction description of
solar neutrino oscillations.Comment: Added predictions for p-p and pep neutrino-electron scattering rate;
publishe
Does the Sun Shine by pp or CNO Fusion Reactions?
We show that solar neutrino experiments set an upper limit of 7.8% (7.3%
including the recent KamLAND measurements) to the fraction of energy that the
Sun produces via the CNO fusion cycle, which is an order of magnitude
improvement upon the previous limit. New experiments are required to detect CNO
neutrinos corresponding to the 1.5% of the solar luminosity that the standard
solar model predicts is generated by the CNO cycle.Comment: Background information at http://www.sns.ias.edu/~jn
Detection of SiO emission from a massive dense cold core
We report the detection of the SiO (J = 2 - 1) transition from the massive
cold dense core G333.125-0.562. The core remains undetected at wavelengths
shorter than 70 micron and has compact 1.2 mm dust continuum. The SiO emission
is localised to the core. The observations are part of a continuing
multi-molecular line survey of the giant molecular cloud G333. Other detected
molecules in the core include 13CO, C18O, CS, HCO+, HCN, HNC, CH3OH, N2H+, SO,
HC3N, NH3, and some of their isotopes. In addition, from NH3 (1,1) and (2,2)
inversion lines, we obtain a temperature of 13 K. From fitting to the spectral
energy distribution we obtain a colour temperature of 18 K and a gas mass of 2
x 10^3 solar mass. We have also detected a 22 GHz water maser in the core,
together with methanol maser emission, suggesting the core will host massive
star formation. We hypothesise that the SiO emission arises from shocks
associated with an outflow in the cold core.Comment: 6 pages, 4 figures, 1 table, to be published in MNRA
Probing Quantized Einstein-Rosen Waves with Massless Scalar Matter
The purpose of this paper is to discuss in detail the use of scalar matter
coupled to linearly polarized Einstein-Rosen waves as a probe to study quantum
gravity in the restricted setting provided by this symmetry reduction of
general relativity. We will obtain the relevant Hamiltonian and quantize it
with the techniques already used for the purely gravitational case. Finally we
will discuss the use of particle-like modes of the quantized fields to
operationally explore some of the features of quantum gravity within this
framework. Specifically we will study two-point functions, the Newton-Wigner
propagator, and radial wave functions for one-particle states.Comment: Accepted for publication in Physical Review
Unveiling quantum entanglement degradation near a Schwarzschild black hole
We analyze the entanglement degradation provoked by the Hawking effect in a
bipartite system Alice-Rob when Rob is in the proximities of a Schwarzschild
black hole while Alice is free falling into it. We will obtain the limit in
which the tools imported from the Unruh entanglement degradation phenomenon can
be used properly, keeping control on the approximation. As a result, we will be
able to determine the degree of entanglement as a function of the distance of
Rob to the event horizon, the mass of the black hole, and the frequency of
Rob's entangled modes. By means of this analysis we will show that all the
interesting phenomena occur in the vicinity of the event horizon and that the
presence of event horizons do not effectively degrade the entanglement when Rob
is far off the black hole. The universality of the phenomenon is presented:
There are not fundamental differences for different masses when working in the
natural unit system adapted to each black hole. We also discuss some aspects of
the localization of Alice and Rob states. All this study is done without using
the single mode approximation.Comment: 16 pages, 10 figures, revtex4. Added Journal referenc
The Circumstellar Structure and Excitation Effects around the Massive Protostar Cepheus A HW 2
We report SMA 335 GHz continuum observations with angular resolution of
~0.''3, together with VLA ammonia observations with ~1'' resolution toward Cep
A HW 2. We find that the flattened disk structure of the dust emission observed
by Patel et al. is preserved at the 0.''3 scale, showing an elongated structure
of ~$0.''6 size (450 AU) peaking on HW 2. In addition, two ammonia cores are
observed, one associated with a hot-core previously reported, and an elongated
core with a double peak separated by ~1.''3 and with signs of heating at the
inner edges of the gas facing HW 2. The double-peaked ammonia structure, as
well as the double-peaked CH3CN structure reported previously (and proposed to
be two independent hot-cores), surround both the dust emission as well as the
double-peaked SO2 disk structure found by Jimenez-Serra et al. All these
results argue against the interpretation of the elongated dust-gas structure as
due to a chance-superposition of different cores; instead, they imply that it
is physically related to the central massive object within a disk-protostar-jet
system.Comment: 12 pages, 3 figures; accepted for publication in the Astrophysical
Journa
Large Solar Neutrino Mixing in an Extended Zee Model
The Zee model, which employs the standard Higgs scalar () with its
duplicate () and a singly charged scalar (), can utilize two
global symmetries associated with the conservation of the numbers of and
, , where coincides
with the hypercharge while () is a new
conserved charge, which is identical to for the left-handed
leptons. Charged leptons turn out to have - and - mixing
masses, which are found to be crucial for the large solar neutrino mixing. In
an extended version of the Zee model with an extra triplet Higgs scalar (s),
neutrino oscillations are described by three steps: 1) the maximal atmospheric
mixing is induced by democratic mass terms supplied by with =2 that can
initiate the type II seesaw mechanism for the smallness of these masses; 2) the
maximal solar neutrino mixing is triggered by the creation of radiative masses
by with = 0; 3) the large solar neutrino mixing is finally induced by
a - mixing arising from the rotation of the radiative mass
terms as a result of the diagonalization that converts - and -
mixing masses into the electron mass.Comment: RevTex, 10 pages including one figure page, to be published in Int.
J. Mod. Phys. A (2002
High Angular Resolution Observations of the Collimated Jet Source Associated with a Massive Protostar in IRAS 16547-4247
A triple radio source recently detected in association with the luminous
infrared source IRAS 16547-4247 has been studied with high angular resolution
and high sensitivity with the Very Large Array at 3.6 and 2 cm. Our
observations confirm the interpretation that the central object is a thermal
radio jet, while the two outer lobes are most probably heavily obscured HH
objects. The thermal radio jet is resolved angularly for the first time and
found to align closely with the outer lobes. The opening angle of the thermal
jet is estimated to be , confirming that collimated outflows can
also be present in massive protostars. The proper motions of the outer lobes
should be measurable over timescales of a few years. Several fainter sources
detected in the region are most probably associated with other stars in a young
cluster.Comment: 9 pages, 2 figure
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