1,625 research outputs found
Constraining new physics scenarios in neutrino oscillations from Daya Bay data
We perform for the first time a detailed fit to the disappearance data of the Daya Bay experiment to constrain the parameter
space of models where sterile neutrinos can propagate in a large compactified
extra dimension (LED) and models where non-standard interactions affect the
neutrino production and detection (NSI). We find that the compactification
radius in LED scenarios can be constrained at the level of
for normal ordering and of for inverted ordering, at 2
confidence level. For the NSI model, reactor data put a strong upper bound on
the parameter at the level of , whereas the
main effect of and is a worsening of
the determination of .Comment: 5 pages, 2 figure
Response to a rabies epidemic in Bali, Indonesia
Emergency vaccinations and culling failed to contain an outbreak of rabies in Bali, Indonesia, during 2008–2009. Subsequent island-wide mass vaccination (reaching 70% coverage, >200,000 dogs) led to substantial declines in rabies incidence and spread. However, the incidence of dog bites remains high, and repeat campaigns are necessary to eliminate rabies in Bali
Probing new physics scenarios in accelerator and reactor neutrino experiments
We perform a detailed combined fit to the disappearence data of the Daya Bay experiment and the
appearance and disappearance data of the Tokai to Kamioka (T2K) one in the presence
of two models of new physics affecting neutrino oscillations, namely a model
where sterile neutrinos can propagate in a large compactified extra dimension
and a model where non-standard interactions (NSI) affect the neutrino
production and detection. We find that the Daya Bay T2K data
combination constrains the largest radius of the compactified extra dimensions
to be at 2 C.L. (for the inverted
ordering of the neutrino mass spectrum) and the relevant NSI parameters in the
range , for particular choices of
the charged parity violating phases.Comment: 18 pages, 10 figures, 4 tables; typos corrected; matches published
versio
Automated search for galactic star clusters in large multiband surveys: I. Discovery of 15 new open clusters in the Galactic anticenter region
Aims: According to some estimations, there are as many as 100000 open
clusters in the Galaxy, but less than 2000 of them have been discovered,
measured, and cataloged. We plan to undertake data mining of multiwavelength
surveys to find new star clusters. Methods: We have developed a new method to
search automatically for star clusters in very large stellar catalogs, which is
based on convolution with density functions. We have applied this method to a
subset of the Two Micron All Sky Survey catalog toward the Galactic anticenter.
We also developed a method to verify whether detected stellar groups are real
star clusters, which tests whether the stars that form the spatial density peak
also fall onto a single isochrone in the color-magnitude diagram. By fitting an
isochrone to the data, we estimate at the same time the main physical
parameters of a cluster: age, distance, color excess. Results: For the present
paper, we carried out a detailed analysis of 88 overdensity peaks detected in a
field of degrees near the Galactic anticenter. From this analysis,
15 overdensities were confirmed to be new open clusters and the physical and
structural parameters were determined for 12 of them; 10 of them were
previously suspected to be open clusters by Kronberger (2006) and Froebrich
(2007). The properties were also determined for 13 yet-unstudied known open
clusters, thus almost tripling the sample of open clusters with studied
parameters in the anticenter. The parameters determined with this method showed
a good agreement with published data for a set of well-known clusters.Comment: accepted to A&
Rotation of the cluster of galaxies A2107
We present indications of rotation in the galaxy cluster A2107 by a method
that searches for the maximum gradient in the velocity field in a flat
disk-like model of a cluster. Galaxies from cumulative sub-samples containing
more and more distant members from the cluster centre, are projected onto an
axis passing through the centre and we apply a linear regression model on the
projected distances and the line-of-sight velocities . The axis with the
maximum linear correlation coefficient defines the
direction of the maximum velocity gradient, and consequently it presents the
major axis of the apparently elliptical cluster. Because the effects of
rotation are subtle, we put strong emphasis on the estimation of the
uncertainties of the results by implementing different bootstrap techniques. We
have found the rotational effects are more strongly expressed from distances
Mpc from the cluster centre. The total virial mass of the
cluster is (3.2\pm0.6)\times10^{14} {\cal M}_{\sun}, while the virial mass,
corrected for the rotation, is (2.8\pm0.5) \times 10^{14}{\cal M}_{\sun}.Comment: 7 pages, 9 figures gzipped tar file. to be published in MNRA
Lie Superalgebras and the Multiplet Structure of the Genetic Code II: Branching Schemes
Continuing our attempt to explain the degeneracy of the genetic code using
basic classical Lie superalgebras, we present the branching schemes for the
typical codon representations (typical 64-dimensional irreducible
representations) of basic classical Lie superalgebras and find three schemes
that do reproduce the degeneracies of the standard code, based on the
orthosymplectic algebra osp(5|2) and differing only in details of the symmetry
breaking pattern during the last step.Comment: 34 pages, 9 tables, LaTe
A Two-Form Formulation of the Vector-Tensor Multiplet in Central Charge Superspace
A two-form formulation for the N=2 vector-tensor multiplet is constructed
using superfield methods in central charge superspace. The N=2 non-Abelian
standard supergauge multiplet in central charge superspace is also discussed,
as is with the associated Chern-Simons form. We give the constraints, solve the
Bianchi identities and present the action for a theory of the vector-tensor
multiplet coupled to the non-Abelian supergauge multiplet via the Chern-Simons
form.Comment: 16 pages, LaTeX2e with AMS-LaTe
Galactic Archaeology with CoRoT and APOGEE: Creating mock observations from a chemodynamical model
In a companion paper, we have presented the combined
asteroseismic-spectroscopic dataset obtained from CoRoT lightcurves and APOGEE
infra-red spectra for 678 solar-like oscillating red giants in two fields of
the Galactic disc (CoRoGEE). We have measured chemical abundance patterns,
distances, and ages of these field stars which are spread over a large radial
range of the Milky Way's disc. Here we show how to simulate this dataset using
a chemodynamical Galaxy model. We also demonstrate how the observation
procedure influences the accuracy of our estimated ages.Comment: 5 pages, 6 figures. To appear in Astronomische Nachrichten, special
issue "Reconstruction the Milky Way's History: Spectroscopic surveys,
Asteroseismology and Chemo-dynamical models", Guest Editors C. Chiappini, J.
Montalb\'an, and M. Steffe
Evolution and Nucleosynthesis of AGB stars in Three Magellanic Cloud Clusters
We present stellar evolutionary sequences for asymptotic giant branch (AGB)
stars in the Magellanic Cloud clusters NGC 1978, NGC 1846 and NGC 419. The new
stellar models for the three clusters match the observed effective temperatures
on the giant branches, the oxygen-rich to carbon-rich transition luminosities,
and the AGB-tip luminosities. A major finding is that a large amount of
convective overshoot (up to 3 pressure scale heights) is required at the base
of the convective envelope during third dredge-up in order to get the correct
oxygen-rich to carbon-rich transition luminosity. The stellar evolution
sequences are used as input for detailed nucleosynthesis calculations. For NGC
1978 and NGC 1846 we compare our model results to the observationally derived
abundances of carbon and oxygen. We find that additional mixing processes
(extra-mixing) are required to explain the observed abundance patterns. For NGC
1846 we conclude that non-convective extra-mixing processes are required on
both the RGB and the AGB, in agreement with previous studies. For NGC 1978 it
is possible to explain the C/O and 12C/13C abundances of both the O-rich and
the C-rich AGB stars by assuming that the material in the intershell region
contains high abundances of both C and O. This may occur during a thermal pulse
when convective overshoot at the inner edge of the flash-driven convective
pocket dredges C and O from the core to the intershell. For NGC 419 we provide
our predicted model abundance values although there are currently no published
observed abundance studies for the AGB stars in this cluster.Comment: 16 figures, 3 tables, Accepted for publication in Ap
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