469 research outputs found
Real-Time 6DOF Pose Relocalization for Event Cameras with Stacked Spatial LSTM Networks
We present a new method to relocalize the 6DOF pose of an event camera solely
based on the event stream. Our method first creates the event image from a list
of events that occurs in a very short time interval, then a Stacked Spatial
LSTM Network (SP-LSTM) is used to learn the camera pose. Our SP-LSTM is
composed of a CNN to learn deep features from the event images and a stack of
LSTM to learn spatial dependencies in the image feature space. We show that the
spatial dependency plays an important role in the relocalization task and the
SP-LSTM can effectively learn this information. The experimental results on a
publicly available dataset show that our approach generalizes well and
outperforms recent methods by a substantial margin. Overall, our proposed
method reduces by approx. 6 times the position error and 3 times the
orientation error compared to the current state of the art. The source code and
trained models will be released.Comment: 7 pages, 5 figure
Preliminary Limits on the WIMP-Nucleon Cross Section from the Cryogenic Dark Matter Search (CDMS)
We are conducting an experiment to search for WIMPs, or weakly-interacting
massive particles, in the galactic halo using terrestrial detectors. This
generic class of hypothetical particles, whose properties are similar to those
predicted by extensions of the standard model of particle physics, could
comprise the cold component of non-baryonic dark matter. We describe our
experiment, which is based on cooled germanium and silicon detectors in a
shielded low-background cryostat. The detectors achieve a high degree of
background rejection through the simultaneous measurement of the energy in
phonons and ionization. Using exposures on the order of one kilogram-day from
initial runs of our experiment, we have achieved (preliminary) upper limits on
the WIMP-nucleon cross section that are comparable to much longer runs of other
experiments.Comment: 5 LaTex pages, 5 eps figs, epsf.sty, espcrc2dsa2.sty. Proceedings of
TAUP97, Gran Sasso, Italy, 7-11 Sep 1997, Nucl. Phys. Suppl., A. Bottino, A.
di Credico and P. Monacelli (eds.). See also http://cfpa.berkeley.ed
Diffractive Phenomena and Shadowing in Deep-Inelastic Scattering
Shadowing effects in deep-inelastic lepton-nucleus scattering probe the mass
spectrum of diffractive leptoproduction from individual nucleons. We explore
this relationship using current experimental information on both processes. In
recent data from the NMC and E665 collaboration, taken at small x << 0.1 and
Q^2 < 1 GeV^2, shadowing is dominated by the diffractive excitation and
coherent interaction of low mass vector mesons. If shadowing is explored at
small x > 1 GeV^2 as discussed at HERA, the situation is
different. Here dominant contributions come from the coherent interaction of
diffractively produced heavy mass states. Furthermore we observe that the
energy dependence of shadowing is directly related to the mass dependence of
the diffractive production cross section for free nucleon targets.Comment: 12 pages Latex, 8 figure
A Large Scale Double Beta and Dark Matter Experiment: GENIUS
The recent results from the HEIDELBERG-MOSCOW experiment have demonstrated
the large potential of double beta decay to search for new physics beyond the
Standard Model. To increase by a major step the present sensitivity for double
beta decay and dark matter search much bigger source strengths and much lower
backgrounds are needed than used in experiments under operation at present or
under construction. We present here a study of a project proposed recently,
which would operate one ton of 'naked' enriched GErmanium-detectors in liquid
NItrogen as shielding in an Underground Setup (GENIUS). It improves the
sensitivity to neutrino masses to 0.01 eV. A ten ton version would probe
neutrino masses even down to 10^-3 eV. The first version would allow to test
the atmospheric neutrino problem, the second at least part of the solar
neutrino problem. Both versions would allow in addition significant
contributions to testing several classes of GUT models. These are especially
tests of R-parity breaking supersymmetry models, leptoquark masses and
mechanism and right-handed W-boson masses comparable to LHC. The second issue
of the experiment is the search for dark matter in the universe. The entire
MSSM parameter space for prediction of neutralinos as dark matter particles
could be covered already in a first step of the full experiment - with the same
purity requirements but using only 100 kg of 76Ge or even of natural Ge -
making the experiment competitive to LHC in the search for supersymmetry.
The layout of the proposed experiment is discussed and the shielding and
purity requirements are studied using GEANT Monte Carlo simulations. As a
demonstration of the feasibility of the experiment first results of operating a
'naked' Ge detector in liquid nitrogen are presented.Comment: 22 pages, 12 figures, see also
http://pluto.mpi-hd.mpg.de/~betalit/genius.htm
MiniBooNE and LSND data: non-standard neutrino interactions in a (3+1) scheme versus (3+2) oscillations
The recently observed event excess in MiniBooNE anti-neutrino data is in
agreement with the LSND evidence for electron anti-neutrino appearance. We
propose an explanation of these data in terms of a (3+1) scheme with a sterile
neutrino including non-standard neutrino interactions (NSI) at neutrino
production and detection. The interference between oscillations and NSI
provides a source for CP violation which we use to reconcile different results
from neutrino and anti-neutrino data. Our best fit results imply NSI at the
level of a few percent relative to the standard weak interaction, in agreement
with current bounds. We compare the quality of the NSI fit to the one obtained
within the (3+1) and (3+2) pure oscillation frameworks. We also briefly comment
on using NSI (in an effective two-flavour framework) to address a possible
difference in neutrino and anti-neutrino results from the MINOS experiment.Comment: 28 pages, 9 figures, discussion improved, new appendix added,
conclusions unchange
Gaugino Anomaly Mediated SUSY Breaking: phenomenology and prospects for the LHC
We examine the supersymmetry phenomenology of a novel scenario of
supersymmetry (SUSY) breaking which we call Gaugino Anomaly Mediation, or
inoAMSB. This is suggested by recent work on the phenomenology of flux
compactified type IIB string theory. The essential features of this scenario
are that the gaugino masses are of the anomaly-mediated SUSY breaking (AMSB)
form, while scalar and trilinear soft SUSY breaking terms are highly
suppressed. Renormalization group effects yield an allowable sparticle mass
spectrum, while at the same time avoiding charged LSPs; the latter are common
in models with negligible soft scalar masses, such as no-scale or gaugino
mediation models. Since scalar and trilinear soft terms are highly suppressed,
the SUSY induced flavor and CP-violating processes are also suppressed. The
lightest SUSY particle is the neutral wino, while the heaviest is the gluino.
In this model, there should be a strong multi-jet +etmiss signal from squark
pair production at the LHC. We find a 100 fb^{-1} reach of LHC out to
m_{3/2}\sim 118 TeV, corresponding to a gluino mass of \sim 2.6 TeV. A double
mass edge from the opposite-sign/same flavor dilepton invariant mass
distribution should be visible at LHC; this, along with the presence of short--
but visible-- highly ionizing tracks from quasi-stable charginos, should
provide a smoking gun signature for inoAMSB.Comment: 30 pages including 14 .eps figure
Results from a Low-Energy Analysis of the CDMS II Germanium Data
We report results from a reanalysis of data from the Cryogenic Dark Matter
Search (CDMS II) experiment at the Soudan Underground Laboratory. Data taken
between October 2006 and September 2008 using eight germanium detectors are
reanalyzed with a lowered, 2 keV recoil-energy threshold, to give increased
sensitivity to interactions from Weakly Interacting Massive Particles (WIMPs)
with masses below ~10 GeV/c^2. This analysis provides stronger constraints than
previous CDMS II results for WIMP masses below 9 GeV/c^2 and excludes parameter
space associated with possible low-mass WIMP signals from the DAMA/LIBRA and
CoGeNT experiments.Comment: 9 pages, 8 figures. Supplemental material included as ancillary
files. v3) Added appendix with additional details regarding energy scale and
background
Search for inelastic dark matter with the CDMS II experiment
Results are presented from a reanalysis of the entire five-tower data set
acquired with the Cryogenic Dark Matter Search (CDMS II) experiment at the
Soudan Underground Laboratory, with an exposure of 969 kg-days. The analysis
window was extended to a recoil energy of 150 keV, and an improved
surface-event background-rejection cut was defined to increase the sensitivity
of the experiment to the inelastic dark matter (iDM) model. Three dark matter
candidates were found between 25 keV and 150 keV. The probability to observe
three or more background events in this energy range is 11%. Because of the
occurrence of these events the constraints on the iDM parameter space are
slightly less stringent than those from our previous analysis, which used an
energy window of 10-100 keV.Comment: 10 pages, 10 figures, minor changes to match published version,
conclusion unchange
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