5,713 research outputs found
Analysis of hidden-bottom bb\bar{b}\bar{b} states
Motivated by the searching for states at LHC recently, we
calculate the ground-state energies of states with quantum
numbers in a nonrelativistic chiral quark model using the
Gaussian expansion method. In our calculations, two structures, meson-meson and
diquark-antidiquark, and their coupling, along with all possible color
configurations are considered. It is expected that the studies shall be helpful
for the experimental searching of fully-heavy exotic tetraquark states.Comment: 7 pages, 1 figur
Is the exotic a bound state?
Stimulated by the recent observation of the exotic state by D0
Collaboration, we study the four-quark system with quantum
numbers in the framework of chiral quark model. Two structures,
diquark-antidiquark and meson-meson, with all possible color configurations are
investigated by using Gaussian expansion method. The results show that energies
of the tetraquark states with diquark-antiquark structure are too high to the
candidate of , and no molecular structure can be formed in our
calculations. The calculation is also extended to the four-quark system
and the same results as that of are
obtained.Comment: 5 pages, 1 figur
The Caltech helicopter control experiment
This report describes the Caltech helicopter control experiment. The experiment consists of an electric model helicopter interfaced to and controlled by a PC. We describe the hardware and software. A state-space model for the angular position is identified from experimental data near hover, using the prediction error method. An LQR controller with integrators for set point tracking is designed for the system. We also undertake a separate identification and loop shaping control for the yaw dynamics
Star-factors of tournaments
Let S_m denote the m-vertex simple digraph formed by m-1 edges with a common
tail. Let f(m) denote the minimum n such that every n-vertex tournament has a
spanning subgraph consisting of n/m disjoint copies of S_m. We prove that m lg
m - m lg lg m <= f(m) <= 4m^2 - 6m for sufficiently large m.Comment: 5 pages, 1 figur
Distributed Optimal Rate-Reliability-Lifetime Tradeoff in Wireless Sensor Networks
The transmission rate, delivery reliability and network lifetime are three
fundamental but conflicting design objectives in energy-constrained wireless
sensor networks. In this paper, we address the optimal
rate-reliability-lifetime tradeoff with link capacity constraint, reliability
constraint and energy constraint. By introducing the weight parameters, we
combine the objectives at rate, reliability, and lifetime into a single
objective to characterize the tradeoff among them. However, the optimization
formulation of the rate-reliability-reliability tradeoff is neither separable
nor convex. Through a series of transformations, a separable and convex problem
is derived, and an efficient distributed Subgradient Dual Decomposition
algorithm (SDD) is proposed. Numerical examples confirm its convergence. Also,
numerical examples investigate the impact of weight parameters on the rate
utility, reliability utility and network lifetime, which provide a guidance to
properly set the value of weight parameters for a desired performance of WSNs
according to the realistic application's requirements.Comment: 27 pages, 10 figure
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