1,214 research outputs found
On the Spontaneous Identity of Chiral and Super Symmetry Breaking in Pure Super Yang Mills Theories
We show that in supersymmetric pure Yang Mills theories with arbitrary simple
gauge group, the spontaneous breaking of chiral fermionic and bosonic charge by
the associated gaugino and gauge boson condensates implies the spontaneous
breaking of supersymmetry by the condensate of the underlying Lagrangian
density. The explicit breaking of the restricted fermionic charge through the
chiral anomaly is deferred to a secondary stage in the elimination of infrared
singularities or long range forces.Comment: 14 pages, uses amsmath, amssymb, shorter version, references added,
eq. (44) correcte
Electromagnetic form factor via Bethe-Salpeter amplitude in Minkowski space
For a relativistic system of two scalar particles, we find the Bethe-Salpeter
amplitude in Minkowski space and use it to compute the electromagnetic form
factor. The comparison with Euclidean space calculation shows that the Wick
rotation in the form factor integral induces errors which increase with the
momentum transfer Q^2. At JLab domain (Q^2=10 GeV^2/c^2), they are about 30%.
Static approximation results in an additional and more significant error. On
the contrary, the form factor calculated in light-front dynamics is almost
indistinguishable from the Minkowski space one.Comment: 8 pages, 7 figures, to be published in Eur. Phys. J. A; Reference
[15] is adde
Elastic Scattering of Neutrinos off Polarized Electrons
We calculate the cross sections for elastic nu_l + e -> nu_l + e and antinu_l
+ e -> antinu_l + e scattering (l=e, mu or tau) in the Born approximation and
with exactly fixed polarization states of target and final-state electrons,
discussing their sensitivity to the incident (anti)neutrino flavor. We suggest
investigation of the flavor composition of a (anti)neutrino beam by a
flux-independent analysis of the scattering of its constituents off polarized
electrons.Comment: 6 pages, 2 figure
Observation of a push force on the end face of a nm fiber taper exerted by outgoing light
There are two different proposals for the momentum of light in a transparent
dielectric of refractive index n: Minkowski's version nE/c and Abrahm's version
E/(nc), where E and c are the energy and vacuum speed of light, respectively.
Despite many tests and debates over nearly a century, momentum of light in a
transparent dielectric remains controversial. In this Letter, we report a
direct observation of the inward push force on the end face of a free nm fiber
taper exerted by the outgoing light. Our results clearly support Abraham
momentum. Our experiment also indicates an inward surface pressure on a
dielectric exerted by the incident light, different from the commonly
recognized pressure due to the specular reflection. Such an inward surface
pressure by the incident light may be useful for precise design of the
laser-induced inertially-confined fusion.Comment: 9 pages, 3 figures;Accepted for publication as a Letter in Physical
Review Letters(CODE: LP11093
Masses and widths of scalar-isoscalar multi-channel resonances from data analysis
Peculiarities of obtaining parameters for broad multi-channel resonances from
data are discussed analyzing the experimental data on processes
in the channel in a
model-independent approach based on analyticity and unitarity and using an
uniformization procedure. We show that it is possible to obtain a good
description of the scattering data from the threshold to 1.89 GeV with
parameters of resonances cited in the PDG tables as preferred. However, in this
case, first, representation of the background is unsatisfactory;
second, the data on the coupled process are not well
described even qualitatively above 1.15 GeV when using the resonance parameters
from the only scattering analysis. The combined analysis of these
coupled processes is needed, which is carried out satisfactorily. Then both
above-indicated flaws, related to the analysis of solely the
-scattering, are cured. The most remarkable change of parameters with
respect to the values of only scattering analysis appears for the mass
of the which is now in some accordance with the Weinberg prediction
on the basis of mended symmetry and with an analysis using the large-
consistency conditions between the unitarization and resonance saturation. The
obtained -scattering length in case when we restrict to the
analysis of the scattering or consider so-called A-solution (with a
lower mass and width of meson) agrees well with prediction of chiral
perturbation theory (ChPT) and with data extracted at CERN by the NA48/2
Collaboration from the analysis of the decay and by the DIRAC
Collaboration from the measurement of the lifetime.Comment: 21 pages, 3 figures, 6 table
Alternative Large Nc Schemes and Chiral Dynamics
We compare the dependences on the number of colors of the leading pion pion
scattering amplitudes using the single index quark field and two index quark
fields. These are seen to have different relationships to the scattering
amplitudes suggested by chiral dynamics which can explain the long puzzling
pion pion s wave scattering up to about 1 GeV. This may be interesting for
getting a better understanding of the large Nc approach as well as for
application to recently proposed technicolor models.Comment: RevTex, two-columns, 6 page
Discreteness of the volume of space from Bohr-Sommerfeld quantization
A major challenge for any theory of quantum gravity is to quantize general
relativity while retaining some part of its geometrical character. We present
new evidence for the idea that this can be achieved by directly quantizing
space itself. We compute the Bohr-Sommerfeld volume spectrum of a tetrahedron
and show that it reproduces the quantization of a grain of space found in loop
gravity.Comment: 4 pages, 4 figures; v2, to appear in PR
Stable quark stars beyond neutran stars : can they account for the missing matter ?
The structure of a spherically symmetric stable dark 'star' is discussed, at
zero temperature, containing 1) a core of quarks in the deconfined phase and
antileptons 2) a shell of hadrons in particular , , and
and leptons or antileptons and 3) a shell of hydrogen in the
superfluid phase. If the superfluid hydrogen phase goes over into the
electromagnetic plasma phase at densities well below one atom / ,
as is usually assumed, the hydrogen shell is insignificant for the mass and the
radius of the 'star'. These quantities are then determined approximatively :
mass = 1.8 solar masses and radius = 9.2 km. On the contrary if densities of
the order of one atom / do form a stable hydrogen superfluid
phase, we find a large range of possible masses from 1.8 to 375 solar masses.
The radii vary accordingly from 9 to 1200 km.Comment: 5 pages, 2 figures, contribution to Strange Quark Matter conference,
Frankfurt, Germany, Sept. 200
Complex amplitude phase motion in Dalitz plot heavy meson three body decay
We propose a method to determine the phase motion of a complex amplitude in
three body heavy meson decays. We show that the phase variation of a complex
amplitude can be directly revealed through the interference observed in the
Dalitz Plot region where it crosses with a well established resonant state.
This method could be applied to the decays \d3pi and , to
determine whether the low mass states and , suggested by E791,
have phase motions compatible with resonances.Comment: To appear in Physics Letters
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