3,085 research outputs found
Generalized top-spin analysis and new physics in collisions with beam polarization
A generalized top-spin analysis proposed some time ago in the context of
Standard Model and subsequently studied in varying contexts is now applied
primarily to the case of with transversely
polarized beams. This extends our recent work with new physics couplings of
scalar () and tensor () types. We carry out a comprehensive analysis
assuming only the electron beam to be transversely polarized, which is
sufficient to probe these interactions, and also eliminates any azimuthal
angular dependence due to standard model or new physics of vector () and
axial-vector () type interactions. We then consider new physics of general
four-Fermi type of and type with both beams transversely polarized and
discuss implications with longitudinal polarization as well. The generalized
spin bases are all investigated in the presence of either longitudinal or
transverse beam polarization to look for appreciable deviation from the SM
prediction in case of the new physics. 90% confidence level limits are obtained
on the interactions for the generalized spin bases with realistic integrated
luminosity. In order to achieve this we present a general discussion based on
helicity amplitudes and derive a general transformation matrix that enables us
to treat the spin basis. We find that beamline basis combined with transverse
polarization provides an excellent window of opportunity both for , and
, new physics, followed by the off diagonal basis. The helicity basis is
shown to be the best in case of longitudinal polarization to look for new
physics effectsdue to and .Comment: 21 pages using revtex4-
4D Topological Mass by Gauging Spin
We propose a spin gauge field theory in which the curl of a Dirac fermion
current density plays the role of the pseudovector charge density. In this
field-theoretic model, spin interactions are mediated by a single scalar gauge
boson in its antisymmetric tensor formulation. We show that these long range
spin interactions induce a gauge invariant photon mass in the one-loop
effective action. The fermion loop generates a coupling between photons and the
spin gauge boson, which acquires thus charge. This coupling represents also an
induced, gauge invariant, topological mass for the photons, leading to the
Meissner effect. The one-loop effective equations of motion for the charged
spin gauge boson are the London equations. We propose thus spin gauge
interactions as an alternative, topological mechanism for superconductivity in
which no spontaneous symmetry breaking is involved.Comment: 4 pages, no figures. arXiv admin note: substantial text overlap with
arXiv:1310.210
Topologically Massive Non-Abelian Gauge Theories: Constraints and Deformations
We study the relationship between three non-Abelian topologically massive
gauge theories, viz. the naive non-Abelian generalization of the Abelian model,
Freedman-Townsend model and the dynamical 2-form theory, in the canonical
framework. Hamiltonian formulation of the naive non-Abelian theory is presented
first. The other two non-Abelian models are obtained by deforming the
constraints of this model. We study the role of the auxiliary vector field in
the dynamical 2-form theory in the canonical framework and show that the
dynamical 2-form theory cannot be considered as the embedded version of naive
non-Abelian model. The reducibility aspect and gauge algebra of the latter
models are also discussed.Comment: ReVTeX, 17 pp; one reference added, version published in Phys. Rev.
Regression Analysis with Linked Data
Record linkage, or exact matching, can be used to join together two files that contain information on the same individuals, but lack unique personal identification codes. The possibility of errors in linkage causes problems for estimating the relationships between variables on the two files. The effect is analogous to the impact of measurement error. A model of a linear regression relationship between variables in linked files is proposed. Assuming the probabilities that pairs of records are links are known, an unbiased estimator of the regression coefficients is derived. Methods for estimating the linkage probabilities by using mixture models are discussed. A consistent estimator of the covariance matrix of the proposed estimator is proposed. A bootstrap estimator is used to reflect the impact of the uncertainty in record linkage model parameters on the estimators of the regression parameters. A simulation study compares the performance of the proposed estimator and alternatives
Temperature-time dependent transmittance, sheet resistance and bonding energy of reduced graphene oxide on soda lime glass.
Reduced graphene oxide coated soda lime glass can act as an alternative transparent/conducting electrode for many opto-electronic applications. However, bonding between the deposited reduced graphene oxide film and the glass substrate is important for achieving better stability of the coating and an extended device lifetime. In the present study, delamination energy of reduced graphene oxide on soda lime glass was quantified by using nanoscratch technique. Graphene oxide was deposited on soda lime glass by dip coating technique and was thermally reduced at different temperatures (100 °C, 200 °C, 300 °C, 400 °C and 500 °C) and treatment time (2 h, 3 h, 4 h, 5 h and 10 h) in Ar (95%) with H2 (5%) atmosphere. An inverse behavior of delamination energy with temperature and treatment time was observed, which could be correlated with the removal of oxygen functional groups. Sheet resistance of the film demonstrated a steady decay with increasing temperature and treatment time. Functional groups attached to the graphene planes have more influence on conductivity than groups attached to the edges. Removal of functional groups could also be related to optical transmittance of the samples. Knowledge generated in this study with respect to delamination energy, sheet resistance and optical transmittance could be extensively used for various opto-electronic applications
Mass generation for non-Abelian antisymmetric tensor fields in a three-dimensional space-time
Starting from a recently proposed Abelian topological model in (2+1)
dimensions, which involve the Kalb-Ramond two form field, we study a
non-Abelian generalization of the model. An obstruction for generalization is
detected. However we show that the goal is achieved if we introduce a vectorial
auxiliary field. Consequently, a model is proposed, exhibiting a non-Abelian
topological mass generation mechanism in D=3, that provides mass for the
Kalb-Ramond field. The covariant quantization of this model requires ghosts for
ghosts. Therefore in order to quantize the theory we construct a complete set
of BRST and anti-BRST equations using the horizontality condition.Comment: 8 pages. To appear in Physical Review
Properties of glitching pulsars in the Skyrme-Hartree-Fock framework
We address the issues of crustal properties of neutron stars such as crustal
mass, crustal radius, crustal fraction of moment of inertia and investigate the
crustal and structural properties related to the glitching mechanism observed
in pulsars. The mass, radius and crustal fraction of moment of inertia in
neutron stars have been determined using -equilibrated (npe) dense
neutron star matter obtained using the extended Skyrme effective interactions
with NRAPR and Brussels-Montreal parameter sets. The maximum mass of neutron
star calculated from these sets is able to reach 2 and higher,
corroborating the recently observed masses of compact stars. The crustal
fraction of the moment of inertia depends sensitively on the pressure and
corresponding density at core-crust transition. The core-crust transition
density and pressure together with the extracted minimum crustal fraction of
the total moment of inertia provide a limit for the radii of pulsars. Present
calculations imply that due to crustal entrainment the crustal fraction of the
total moment of inertia is about 5.5.Comment: 10 pages including 6 figures and 3 tables. All calculations have been
performed again using latest values of physical constants. Figures and tables
are modified accordingly. Also added a few new relevant reference
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