30,596 research outputs found
Integrating Out Astrophysical Uncertainties
Underground searches for dark matter involve a complicated interplay of
particle physics, nuclear physics, atomic physics and astrophysics. We attempt
to remove the uncertainties associated with astrophysics by developing the
means to map the observed signal in one experiment directly into a predicted
rate at another. We argue that it is possible to make experimental comparisons
that are completely free of astrophysical uncertainties by focusing on {\em
integral} quantities, such as and
. Direct comparisons are possible when the
space probed by different experiments overlap. As examples, we
consider the possible dark matter signals at CoGeNT, DAMA and CRESST-Oxygen. We
find that expected rate from CoGeNT in the XENON10 experiment is higher than
observed, unless scintillation light output is low. Moreover, we determine that
S2-only analyses are constraining, unless the charge yield . For DAMA to be consistent with XENON10, we find for
that the modulation rate must be extremely high (\gsim 70% for
m_\chi = 7\, \gev), while for higher quenching factors, it makes an explicit
prediction (0.8 - 0.9 cpd/kg) for the modulation to be observed at CoGeNT.
Finally, we find CDMS-Si, even with a 10 keV threshold, as well as XENON10,
even with low scintillation, would have seen significant rates if the excess
events at CRESST arise from elastic WIMP scattering, making it very unlikely to
be the explanation of this anomaly.Comment: 25 pages, 7 figures; v2 replaced with published versio
TEQUILA: Temporal Question Answering over Knowledge Bases
Question answering over knowledge bases (KB-QA) poses challenges in handling complex questions that need to be decomposed into sub-questions. An important case, addressed here, is that of temporal questions, where cues for temporal relations need to be discovered and handled. We present TEQUILA, an enabler method for temporal QA that can run on top of any KB-QA engine. TEQUILA has four stages. It detects if a question has temporal intent. It decomposes and rewrites the question into non-temporal sub-questions and temporal constraints. Answers to sub-questions are then retrieved from the underlying KB-QA engine. Finally, TEQUILA uses constraint reasoning on temporal intervals to compute final answers to the full question. Comparisons against state-of-the-art baselines show the viability of our method
Relaxed 2-D Principal Component Analysis by Norm for Face Recognition
A relaxed two dimensional principal component analysis (R2DPCA) approach is
proposed for face recognition. Different to the 2DPCA, 2DPCA- and G2DPCA,
the R2DPCA utilizes the label information (if known) of training samples to
calculate a relaxation vector and presents a weight to each subset of training
data. A new relaxed scatter matrix is defined and the computed projection axes
are able to increase the accuracy of face recognition. The optimal -norms
are selected in a reasonable range. Numerical experiments on practical face
databased indicate that the R2DPCA has high generalization ability and can
achieve a higher recognition rate than state-of-the-art methods.Comment: 19 pages, 11 figure
Deprojection technique for galaxy cluster considering point spread function
We present a new method for the analysis of Abell 1835 observed by
XMM-Newton. The method is a combination of the Direct Demodulation technique
and deprojection. We eliminate the effects of the point spread function (PSF)
with the Direct Demodulation technique. We then use a traditional depro-jection
technique to study the properties of Abell 1835. Compared to that of
deprojection method only, the central electron density derived from this method
increases by 30%, while the temperature profile is similar.Comment: accepted for publication in Sciences in China -- G, the Black Hole
special issu
U(1)-decoupling, KK and BCJ relations in SYM
We proved the color reflection relation, U(1)-decoupling, Kleiss-Kuijf and
Bern-Carrasco-Johansson relation for color-ordered Super
Yang-Mills theory using SYM version BCFW recursion relation,
which depends only on the general properties of super-amplitudes. This verified
the conjectured matter fields BCJ relation. We also show that color reflection
relation and U(1)-decoupling relation are special cases of KK relation, if we
consider the KK relation as a general relation, then the former two relations
come out naturally as the special cases.Comment: 17 page
Measurement of elliptic and higher order flow harmonics at TeV Pb+Pb collisions with the ATLAS Detector
The measurements of flow harmonics - using the event plane and two
particle correlations methods in broad , and centrality ranges
using the ATLAS detector at LHC are presented. ATLAS recorded about 9 of lead-lead collision data in the 2010 heavy ion run. The
full azimuthal acceptance of the ATLAS detector in units of
pseudorapidity for charged hadrons and the large amount of data allows for a
detailed study of the flow harmonics. The , centrality and ranges
where the two methods give consistent and where they disagree are
discussed. It is shown that the ridge as well as the so called "mach-cone" seen
in two particle correlations are largely accounted for by the collective flow.
Some scaling relations in the dependence of the are also discussed
The CJT calculation in studying nuclear matter beyond mean field approximation
We have introduced a CJT calculation in studying nuclear matter beyond mean
field approximation. Based on the CJT formalism and using Walecka model, we
have derived a set of coupled Dyson equations of nucleons and mesons.
Neglecting the medium effects of the mesons, the usual MFT results could be
reproduced. The beyond MFT calculations have been performed by thermodynamic
consistently determining the meson effective masses and solving the coupled gap
equations for nucleons and mesons. The numerical results for the nucleon and
meson effective masses at finite temperature and chemical potential in nuclear
matter are discussed.Comment: 8 pages, 8 figure
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