6,463 research outputs found
Laboratory testing of candidate robotic applications for space
Robots have potential for increasing the value of man's presence in space. Some categories with potential benefit are: (1) performing extravehicular tasks like satellite and station servicing, (2) supporting the science mission of the station by manipulating experiment tasks, and (3) performing intravehicular activities which would be boring, tedious, exacting, or otherwise unpleasant for astronauts. An important issue in space robotics is selection of an appropriate level of autonomy. In broad terms three levels of autonomy can be defined: (1) teleoperated - an operator explicitly controls robot movement; (2) telerobotic - an operator controls the robot directly, but by high-level commands, without, for example, detailed control of trajectories; and (3) autonomous - an operator supplies a single high-level command, the robot does all necessary task sequencing and planning to satisfy the command. Researchers chose three projects for their exploration of technology and implementation issues in space robots, one each of the three application areas, each with a different level of autonomy. The projects were: (1) satellite servicing - teleoperated; (2) laboratory assistant - telerobotic; and (3) on-orbit inventory manager - autonomous. These projects are described and some results of testing are summarized
The -parity Violating Decays of Charginos and Neutralinos in the B-L MSSM
The MSSM is the MSSM with three right-handed neutrino chiral multiplets
and gauged symmetry. The symmetry is broken by the third family
right-handed sneutrino acquiring a VEV, thus spontaneously breaking -parity.
Within a natural range of soft supersymmetry breaking parameters, it is shown
that a large and uncorrelated number of initial values satisfy all present
phenomenological constraints; including the correct masses for the ,
bosons, having all sparticles exceeding their present lower bounds and
giving the experimentally measured value for the Higgs boson. For this "valid"
set of initial values, there are a number of different LSPs, each occurring a
calculable number of times. We plot this statistically and determine that among
the most prevalent LSPs are chargino and neutralino mass eigenstates. In this
paper, the -parity violating decay channels of charginos and neutralinos to
standard model particles are determined, and the interaction vertices and decay
rates computed analytically. These results are valid for any chargino and
neutralino, regardless of whether or not they are the LSP. For chargino and
neutralino LSPs, we will-- in a subsequent series of papers --present a
numerical study of their RPV decays evaluated statistically over the range of
associated valid initial points.Comment: 62 pages, 12 figures, added references in section 1, corrected some
calculation error
The Minimal SUSY Model: From the Unification Scale to the LHC
This paper introduces a random statistical scan over the high-energy initial
parameter space of the minimal SUSY model--denoted as the MSSM.
Each initial set of points is renormalization group evolved to the electroweak
scale--being subjected, sequentially, to the requirement of radiative and
electroweak symmetry breaking, the present experimental lower bounds on the
vector boson and sparticle masses, as well as the lightest neutral Higgs
mass of 125 GeV. The subspace of initial parameters that satisfies all
such constraints is presented, shown to be robust and to contain a wide range
of different configurations of soft supersymmetry breaking masses. The
low-energy predictions of each such "valid" point - such as the sparticle mass
spectrum and, in particular, the LSP - are computed and then statistically
analyzed over the full subspace of valid points. Finally, the amount of
fine-tuning required is quantified and compared to the MSSM computed using an
identical random scan. The MSSM is shown to generically require less
fine-tuning.Comment: 65 pages, 18 figure
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