25,728 research outputs found
Yukawa Bound States of a Large Number of Fermions
We consider the bound state problem for a field theory that contains a Dirac
fermion that Yukawa couples to a (light) scalar field . We are
interested in bound states with a large number of particles. A Fermi
gas model is used to numerically determine the dependence of the radius of
these bound states on and also the dependence of the binding energy on .
Since scalar interactions with relativistic 's are suppressed two regimes
emerge. For modest values of the state is composed of non-relativistic
particles. In this regime as increases decreases. Eventually the
core region becomes relativistic and the size of the state starts to increase
as increases. As a result, for fixed Yukawa coupling and mass, there
is a minimum sized state that occurs roughly at the value of where the core
region first becomes relativistic. We also compute an elastic scattering form
factor that can be relevant for direct detection if the dark matter is composed
of such particles.Comment: 14 pages, 7 figure
Effect of a thin optical Kerr medium on a Laguerre-Gaussian beam
Using a generalized Gaussian beam decomposition method we determine the
propagation of a Laguerre-Gaussian beam that has passed through a thin
nonlinear optical Kerr medium. The orbital angular momentum per photon of the
beam is found to be conserved while the component beams change. As an
illustration of applications, we propose and demonstrate a z-scan experiment
using an beam and a dye-doped polymer film.Comment: 3 pages, 2 figures, corrected typo
Effective Theory and Simple Completions for Neutrino Interactions
We consider all the dimension 6 operators as well as some simple extensions
of the standard model that give new contributions to neutrino interactions with
matter. Such interactions are usually parametrized by , where and are neutrino flavor indices taking the
values , and . In the simple models we consider the
's are much more constrained than in the
operator-based model-independent approach. Typically the 's are restricted to be smaller in magnitude than around . In
some of the leptoquark models, a specific pattern for the leptoquark Yukawa
couplings allows the diagonal element to be as large as
, or one of , . We discuss
the interplay between neutrino physics and leptoquark searches at the LHC.Comment: 12 pages, 2 figure
Relationships among Interpolation Bases of Wavelet Spaces and Approximation Spaces
A multiresolution analysis is a nested chain of related approximation
spaces.This nesting in turn implies relationships among interpolation bases in
the approximation spaces and their derived wavelet spaces. Using these
relationships, a necessary and sufficient condition is given for existence of
interpolation wavelets, via analysis of the corresponding scaling functions. It
is also shown that any interpolation function for an approximation space plays
the role of a special type of scaling function (an interpolation scaling
function) when the corresponding family of approximation spaces forms a
multiresolution analysis. Based on these interpolation scaling functions, a new
algorithm is proposed for constructing corresponding interpolation wavelets
(when they exist in a multiresolution analysis). In simulations, our theorems
are tested for several typical wavelet spaces, demonstrating our theorems for
existence of interpolation wavelets and for constructing them in a general
multiresolution analysis
Lepton Flavorful Fifth Force and Depth-dependent Neutrino Matter Interactions
We consider a fifth force to be an interaction that couples to matter with a
strength that grows with the number of atoms. In addition to competing with the
strength of gravity a fifth force can give rise to violations of the
equivalence principle. Current long range constraints on the strength and range
of fifth forces are very impressive. Amongst possible fifth forces are those
that couple to lepton flavorful charges or . They
have the property that their range and strength are also constrained by
neutrino interactions with matter. In this brief note we review the existing
constraints on the allowed parameter space in gauged . We find two regions where neutrino oscillation experiments are at
the frontier of probing such a new force. In particular, there is an allowed
range of parameter space where neutrino matter interactions relevant for long
baseline oscillation experiments depend on the depth of the neutrino beam below
the surface of the earth.Comment: 6 pages, 5 figure
A Unified and Complete Construction of All Finite Dimensional Irreducible Representations of gl(2|2)
Representations of the non-semisimple superalgebra in the standard
basis are investigated by means of the vector coherent state method and
boson-fermion realization. All finite-dimensional irreducible typical and
atypical representations and lowest weight (indecomposable) Kac modules of
are constructed explicitly through the explicit construction of all
particle states (multiplets) in terms of boson and fermion
creation operators in the super-Fock space. This gives a unified and complete
treatment of finite-dimensional representations of in explicit form,
essential for the construction of primary fields of the corresponding current
superalgebra at arbitrary level.Comment: LaTex file, 23 pages, two references and a comment added, to appear
in J. Math. Phy
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