10,391 research outputs found
Prospects for Detecting Neutrino Signals from Annihilating/Decaying Dark Matter to Account for the PAMELA and ATIC results
Recent PAMELA data show that positron fraction has an excess above several
GeV while anti-proton one is not. Moreover ATIC data indicates that
electron/positron flux have a bump from 300 GeV to 800 GeV. Both annihilating
dark matter (DM) with large boost factor and decaying DM with the life around can account for the PAMELA and ATIC observations if their main final
products are charged leptons (, and ). In this work, we
calculated the neutrino flux arising from and which originate from
annihilating/decaying DM, and estimated the final muon rate in the neutrino
telescopes, namely Antares and IceCube. Given the excellent angular resolution,
Antares and IceCube are promising to discover the neutrino signals from
Galactic center and/or large DM subhalo in annihilating DM scenario, but very
challenging in decaying DM scenario.Comment: 21 pages, 7 figures, 2 tables. V2: references added. V3: the number
density of massive subhalo has been discussed in the appendix; accepted by
PR
Semiparametric GEE analysis in partially linear single-index models for longitudinal data
In this article, we study a partially linear single-index model for
longitudinal data under a general framework which includes both the sparse and
dense longitudinal data cases. A semiparametric estimation method based on a
combination of the local linear smoothing and generalized estimation equations
(GEE) is introduced to estimate the two parameter vectors as well as the
unknown link function. Under some mild conditions, we derive the asymptotic
properties of the proposed parametric and nonparametric estimators in different
scenarios, from which we find that the convergence rates and asymptotic
variances of the proposed estimators for sparse longitudinal data would be
substantially different from those for dense longitudinal data. We also discuss
the estimation of the covariance (or weight) matrices involved in the
semiparametric GEE method. Furthermore, we provide some numerical studies
including Monte Carlo simulation and an empirical application to illustrate our
methodology and theory.Comment: Published at http://dx.doi.org/10.1214/15-AOS1320 in the Annals of
Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical
Statistics (http://www.imstat.org
Four Jets as a Probe of O(100 GeV) Physics beyond Standard Model at Hadron Colliders
O(100 GeV) physics beyond the standard model (BSM) could be overlooked
provided that it is hidden in the untouched Higgs sector or jets. The top quark
forward-backward asymmetry measurements and di-jet bump, which is observed in
the associated production with charged lepton plus missing energy (supposed
arising from W decay), may indicate the existence of a new color-octet
axial-vector Z_C with a mass about 145 GeV. Here Z_C only decays into two jets.
In this paper we investigated the possibility to discover Z_C pair via
analyzing the four jets as the final states, which are heavily polluted by huge
QCD background. Our simulation showed that, however, both Tevatron and LHC have
the excellent chance to discover Z_C through analyzing the four jets events in
the current accumulated data.Comment: 15 pages, 11figures and 2 table
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