10,002 research outputs found

### Recent Results from Daya Bay Reactor Neutrino Experiment

The Daya Bay reactor neutrino experiment announced the discovery of a
non-zero value of \sin^22\theta_{13} with significance better than 5 \sigma in
2012. The experiment is continuing to improve the precision of
\sin^22\theta_{13} and explore other physics topics. In this talk, I will show
the current oscillation and mass-squared difference results which are based on
the combined analysis of the measured rates and energy spectra of antineutrino
events, an independent measurement of \theta_{13} using IBD events where
delayed neutrons are captured on hydrogens, and a search for light sterile
neutrinos.Comment: this proceedings is for the Moriond 2015 EW sessio

### New Results from the Daya Bay Reactor Neutrino Experiment

This presentation describes a precision result of the neutrino mixing
parameter, $\sin^2 2\theta_{13}$, and the first direct measurement of the
antineutrino mass-squared difference $\sin^2(\Delta_{ee}) \equiv \cos^2
\theta_{12} \sin^2 \Delta_{31} + \sin^2 \theta_{12} \sin^2 \Delta_{32}$ from
the Daya Bay Reactor Neutrino Experiment. The above results are based on the
six detector data-taking from 24 December 2011 to 28 July 2012. By using the
observed antineutrino rate and the energy spectrum analysis, the results are
$\sin^2 2\theta_{13}=0.090^{+0.008}_{-0.009}$ and $| \Delta m^2_{ee}| =
2.59^{+0.19}_{-0.20} \cdot 10^{-3}$eV$^2$ with a $\chi^2$/NDF of 162.7/153.
The value of $| \Delta m^2_{ee}|$ is consistent with $| \Delta m^2_{\mu\mu}|$
measured in muon neutrino beam experiments.Comment: to appear in the proceedings of The 10th International Symposium on
Cosmology and Particle Astrophysics (CosPA2013

### Asymptotic behavior of the nonlinear Schr\"{o}dinger equation on exterior domain

{\bf Abstract} \,\, We consider the following nonlinear Schr\"{o}dinger
equation on exterior domain. \begin{equation} \begin{cases} iu_t+\Delta_g u +
ia(x)u - |u|^{p-1}u = 0 \qquad (x,t) \in \Omega\times (0,+\infty), \qquad
(1)\cr u\big|_\Gamma = 0\qquad t \in (0,+\infty), \cr u(x,0) = u_0(x)\qquad x
\in \Omega, \end{cases} \end{equation} where $1<p<\frac{n+2}{n-2}$,
$\Omega\subset\mathbb{R}^n$ ($n\ge3$) is an exterior domain and
$(\mathbb{R}^n,g)$ is a complete Riemannian manifold. We establish Morawetz
estimates for the system (1) without dissipation ($a(x)\equiv 0$ in (1)) and
meanwhile prove exponential stability of the system (1) with a dissipation
effective on a neighborhood of the infinity.
It is worth mentioning that our results are different from the existing
studies. First, Morawetz estimates for the system (1) are directly derived from
the metric $g$ and are independent on the assumption of an (asymptotically)
Euclidean metric. In addition, we not only prove exponential stability of the
system (1) with non-uniform energy decay rate, which is dependent on the
initial data, but also prove exponential stability of the system (1) with
uniform energy decay rate. The main methods are the development of Morawetz
multipliers in non (asymptotically) Euclidean spaces and compactness-uniqueness
arguments.Comment: 25 page

### On the Complexity of One-class SVM for Multiple Instance Learning

In traditional multiple instance learning (MIL), both positive and negative
bags are required to learn a prediction function. However, a high human cost is
needed to know the label of each bag---positive or negative. Only positive bags
contain our focus (positive instances) while negative bags consist of noise or
background (negative instances). So we do not expect to spend too much to label
the negative bags. Contrary to our expectation, nearly all existing MIL methods
require enough negative bags besides positive ones. In this paper we propose an
algorithm called "Positive Multiple Instance" (PMI), which learns a classifier
given only a set of positive bags. So the annotation of negative bags becomes
unnecessary in our method. PMI is constructed based on the assumption that the
unknown positive instances in positive bags be similar each other and
constitute one compact cluster in feature space and the negative instances
locate outside this cluster. The experimental results demonstrate that PMI
achieves the performances close to or a little worse than those of the
traditional MIL algorithms on benchmark and real data sets. However, the number
of training bags in PMI is reduced significantly compared with traditional MIL
algorithms

### Two Stronger Versions of the Union-closed Sets Conjecture

The union-closed sets conjecture (Frankl's conjecture) says that for any
finite union-closed family of finite sets, other than the family consisting
only of the empty set, there exists an element that belongs to at least half of
the sets in the family. In this paper, we introduce two stronger versions of
Frankl's
conjecture and give a partial proof. Three related questions are introduced.Comment: 26 pages; a typo on Page 23 was revise

### Jensen's Inequality for Backward SDEs Driven by $G$-Brownian motion

In this note, we consider Jensen's inequality for the nonlinear expectation
associated with backward SDEs driven by $G$-Brownian motion ($G$-BSDEs for
short). At first, we give a necessary and sufficient condition for $G$-BSDEs
under which one-dimensional Jensen inequality holds. Second, we prove that for
$n>1$, the $n$-dimensional Jensen inequality holds for any nonlinear
expectation if and only if the nonlinear expectation is linear, which is
essentially due to Jia (Arch. Math. 94 (2010), 489-499). As a consequence, we
give a necessary and sufficient condition for $G$-BSDEs under which the
$n$-dimensional Jensen inequality holds.Comment: 11 page

### Study of $s\to d\nu\bar{\nu}$ rare hyperon decays within the Standard Model and new physics

FCNC processes offer important tools to test the Standard Model (SM), and to
search for possible new physics. In this work, we investigate the $s\to
d\nu\bar{\nu}$ rare hyperon decays in SM and beyond. We find that in SM the
branching ratios for these rare hyperon decays range from $10^{-14}$ to
$10^{-11}$. When all the errors in the form factors are included, we find that
the final branching fractions for most decay modes have an uncertainty of about
$5\%$ to $10\%$. After taking into account the contribution from new physics,
the generalized SUSY extension of SM and the minimal 331 model, the decay
widths for these channels can be enhanced by a factor of $2 \sim 7$.Comment: 9 pages, 5 table

### Escape Metrics and its Applications

Geodesics escape is widely used to study the scattering of hyperbolic
equations. However, there are few progresses except in a simply connected
complete Riemannian manifold with nonpositive curvature. We propose a kind of
complete Riemannian metrics in $\mathbb{R}^n$, which is called as escape
metrics. We expose the relationship between escape metrics and geodesics escape
in $\mathbb{R}^n$. Under the escape metric $g$, we prove that each geodesic of
$(\mathbb{R}^n,g)$ escapes, that is, $\lim_{t\rightarrow +\infty} |\gamma
(t)|=+\infty$ for any $x\in \mathbb{R}^n$ and any unit-speed geodesic $\gamma
(t)$ starting at $x$. We also obtain the geodesics escape velocity and give the
counterexample that if escape metrics are not satisfied, then there exists an
unit-speed geodesic $\gamma (t)$ such that $\overline{\lim}_{t\rightarrow
+\infty} |\gamma (t)|<+\infty$. In addition, we establish Morawetz multipliers
in Riemannian geometry to derive dispersive estimates for the wave equation on
an exterior domain of $\mathbb{R}^n$ with an escape metric. More concretely,
for radial solutions, the uniform decay rate of the local energy is independent
of the parity of the dimension $n$. For general solutions, we prove the
space-time estimation of the energy and uniform decay rate $t^{-1}$ of the
local energy. It is worth pointing out that different from the assumption of an
Euclidean metric at infinity in the existing studies, escape metrics are more
general Riemannian metrics.Comment: 28 page

### Special uniform decay rate of local energy for the wave equation with variable coefficients on an exterior domain

We consider the wave equation with variable coefficients on an exterior
domain in $\R^n$($n\ge 2$). We are interested in finding a special uniform
decay rate of local energy different from the constant coefficient wave
equation.
More concretely, if the dimensional $n$ is even, whether the uniform decay
rate of local energy for the wave equation with variable coefficients can break
through the limit of polynomial and reach exponential; if the dimensional $n$
is odd, whether the uniform decay rate of local energy for the wave equation
with variable coefficients can hold exponential as the constant coefficient
wave equation .
\quad \ \ We propose a cone and establish Morawetz's multipliers in a version
of the Riemannian geometry to derive uniform decay of local energy for the wave
equation with variable coefficients. We find that the cone with polynomial
growth is closely related to the uniform decay rate of the local energy. More
concretely, for radial solutions, when the cone has polynomial of degree
$\frac{n}{2k-1}$ growth, the uniform decay rate of local energy is exponential;
when the cone has polynomial of degree $\frac{n}{2k}$ growth, the uniform decay
rate of local energy is polynomial at most. In addition, for general solutions,
when the cone has polynomial of degree $n$ growth, we prove that the uniform
decay rate of local energy is exponential under suitable Riemannian metric. It
is worth pointing out that such results are independent of the parity of the
dimension $n$, which is the main difference with the constant coefficient wave
equation. Finally, for general solutions, when the cone has polynomial of
degree $m$ growth, where $m$ is any positive constant, we prove that the
uniform decay rate of the local energy is of primary polynomial under suitable
Riemannian metric.Comment: 23 pages. arXiv admin note: text overlap with arXiv:1811.1266

### MIMO UWB Radar System with Compressive Sensing

A multiple input multiple output ultra-wideband cognitive radar based on
compressive sensing is presented in this letter. For traditional UWB radar,
high sampling rate analog to digital converter at the receiver is required to
meet Shannon theorem, which increases hardware complexity. In order to bypass
the bottleneck of ADC or further increase the radar bandwidth using the latest
wideband ADC, we propose to exploit CS for signal reconstruction at the
receiver of UWB radar for the sparse targets in the surveillance area. Besides,
the function of narrowband interference cancellation is integrated into the
proposed MIMO UWB radar. The field demonstration proves the feasibility and
reliability of the proposed algorithm.Comment: 4 page

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