17,675 research outputs found
Fluctuation limits of strongly degenerate branching systems
Functional limit theorems for scaled fluctuations of occupation time
processes of a sequence of critical branching particle systems in with
anisotropic space motions and strongly degenerated splitting abilities are
proved in the cases of critical and intermediate dimensions. The results show
that the limit processes are constant measure-valued Wienner processes with
degenerated temporal and simple spatial structures.Comment: 15 page
SUSY QCD Corrections to Higgs Pair Production from Bottom Quark Fusion
We present a complete next-to-leading order (NLO) calculation for the total
cross section for inclusive Higgs pair production via bottom-quark fusion at
the CERN Large Hadron Collider (LHC) in the minimal supersymmetric standard
model (MSSM) and the minimal supergravity model (mSUGRA). We emphasize the
contributions of squark and gluino loops (SQCD) and the decoupling properties
of our results for heavy squark and gluino masses. The enhanced couplings of
the b quark to the Higgs bosons in supersymmetric models with large tanb yield
large NLO SQCD corrections in some regions of parameter space.Comment: 24 pages, 10 figure
The Kaon B-parameter from Quenched Domain-Wall QCD
We present numerical results for the kaon B-parameter, B_K, determined in the
quenched approximation of lattice QCD. Our simulations are performed using
domain-wall fermions and the renormalization group improved, DBW2 gauge action
which combine to give quarks with good chiral symmetry at finite lattice
spacing. Operators are renormalized non-perturbatively using the RI/MOM scheme.
We study scaling by performing the simulation on two different lattices with
a^{-1} = 1.982(30) and 2.914(54) GeV. We combine this quenched scaling study
with an earlier calculation of B_K using two flavors of dynamical, domain-wall
quarks at a single lattice spacing to obtain
B_K(MS,NDR,mu=2GeV)=0.563(21)(39)(30), were the first error is statistical, the
second systematic (without quenching errors) and the third estimates the error
due to quenching.Comment: 77 pages, 44 figures, to be published in Phys. Rev.
Angular Dependence of the High-Magnetic-Field Phase Diagram of URu2Si2
We present measurements of the magnetoresistivity RHOxx of URu2Si2 single
crystals in high magnetic fields up to 60 T and at temperatures from 1.4 K to
40 K. Different orientations of the magnetic field have been investigated
permitting to follow the dependence on Q of all magnetic phase transitions and
crossovers, where Q is the angle between the magnetic field and the easy-axis
c. We find out that all magnetic transitions and crossovers follow a simple
1/cos(Q) -law, indicating that they are controlled by the projection of the
field on the c-axis
Nonlinear Control Strategy for Advanced Vehicle Thermal Management Systmes
Advanced thermal management systems for internal combustion engines can improve coolant temperature regulation and servomotor power consumption by better regulating the combustion process with multiple computer controlled electromechanical components. The traditional thermostat valve, coolant pump, and clutch-driven radiator fan are upgraded with servomotor actuators. When the system components function harmoniously, desired thermal conditions can be accomplished in a power efficient manner. In this paper, a comprehensive nonlinear control architecture is proposed for transient temperature tracking. An experimental system has been fabricated and assembled which features a variable position smart valve, variable speed electric water pump, variable speed electric radiator fan, engine block, and various sensors. In the configured system, the steam-based heat exchanger emulates the heat generated by the engine’s combustion process. Representative numerical and experimental results are discussed to demonstrate the functionality of the thermal management system in accurately tracking prescribed temperature profiles and minimizing electrical power consumption
An Analysis of the Telecommunication Performance of a Data Relay Satellite System
The Data-Relay Satellite System (DRSS) has been proposed as a means of providing a communication capability between a number of earth-orbiting space vehicles and the Mission Control Center- Houston (MCC-H) using earth-orbiting synchronous satellites as relay devices. The purpose of this paper is to report the investigation of the performance characteristics of the relay system and to determine the expected communications capabilities of the DRSS operating with Apollo spacecraft systems and with an advanced spacecraft-systems concept.
When the DRSS is used with the spacecraft high-gain antenna (Apollo or modified spacecraft), positive circuit margins can be expected for all up-link and down-link, pulse modulated (PM) modes, which include pseudorandom noise (PRN) ranging, telemetry, and voice. Wideband frequency modulated (FM) modes (television or 1-Mbps data dump) have positive circuit margins for the modified spacecraft system configuration; however, only marginal performance can be expected with the Apollo system
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