22,627 research outputs found
Superfield Approach to Nilpotency and Absolute Anticommutativity of Conserved Charges: 2D non-Abelian 1-Form Gauge Theory
We exploit the theoretical strength of augmented version of superfield
approach (AVSA) to Becchi-Rouet-Stora-Tyutin (BRST) formalism to express the
nilpotency and absolute anticommutativity properties of the (anti-)BRST and
(anti-)co-BRST conserved charges for the two -dimensional (2D)
non-Abelian 1-form gauge theory (without any interaction with matter fields) in
the language of superspace variables, their derivatives and suitable
superfields. In the proof of absolute anticommutativity property, we invoke the
strength of Curci-Ferrari (CF) condition for the (anti-)BRST charges. No such
outside condition/restriction is required in the proof of absolute
anticommutativity of the (anti-)co-BRST conserved charges. The latter
observation (as well as other observations) connected with (anti-)co-BRST
symmetries and corresponding conserved charges are novel results of our present
investigation. We also discuss the (anti-)BRST and (anti-)co-BRST symmetry
invariance of the appropriate Lagrangian densities within the framework of
AVSA. In addition, we dwell a bit on the derivation of the above fermionic
(nilpotent) symmetries by applying the AVSA to BRST formaism where only the
(anti-)chiral superfields are used.Comment: LaTeX file, 33 pages, journal referenc
Constraints on the Neutrino Parameters from the `Rise-up' in the Boron Neutrino Spectrum at Low Energies
The rise-up in boron neutrino spectrum at low energies has been studied
within the framework of `pure LMA' scenario. Indirect bounds on the spectral
`upturn' have been obtained from the available solar neutrino data. These
bounds have been used to demonstrate the efficacy of the precision measurements
of the `upturn' for further constraining the neutrino parameter space allowed
by SNO salt phase data. The sterile neutrino flux has been constrained in the
light of the recent 766.3 Ty KamLAND spectral data.Comment: Latex 10pages including 3 postscript figure
Magneto-inductive skin sensor for robot collision avoidance: A new development
Safety is a primary concern for robots operating in space. The tri-mode sensor addresses that concern by employing a collision avoidance/management skin around the robot arms. This rf-based skin sensor is at present a dual mode (proximity and tactile). The third mode, pyroelectric, will complement the other two. The proximity mode permits the robot to sense an intruding object, to range the object, and to detect the edges of the object. The tactile mode permits the robot to sense when it has contacted an object, where on the arm it has made contact, and provides a three-dimensional image of the shape of the contact impression. The pyroelectric mode will be added to permit the robot arm to detect the proximity of a hot object and to add sensing redundancy to the two other modes. The rf-modes of the sensing skin are presented. These modes employ a highly efficient magnetic material (amorphous metal) in a sensing technique. This results in a flexible sensor array which uses a primarily inductive configuration to permit both capacitive and magnetoinductive sensing of object; thus optimizing performance in both proximity and tactile modes with the same sensing skin. The fundamental operating principles, design particulars, and theoretical models are provided to aid in the description and understanding of this sensor. Test results are also given
Solar Neutrinos: Spin Flavour Precession and LMA
The time dependence that appears to be hinted by the data from the first 13
years of the solar neutrino Gallium experiments is viewed as resulting from a
partial conversion of active neutrinos to light sterile ones through the
resonant interaction between the magnetic moment of the neutrino and a varying
solar field. A summary of the model and its predictions are presented for the
forthcoming experiments Borexino and LENS.Comment: 6 pages, 3 figures, contribution to 12th Lomonosov Conference in
Elementary Particle Physics, Moscow, Aug 24-31 (2005
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