1,113 research outputs found
Is Cosmic Parity Violation Responsible for the Anomalies in the WMAP Data?
This research demonstrates that parity violation in general relativity can
simultaneously explain the observed loss in power and alignment at a preferred
axis ('Axis of Evil')in the low multipole moments of the WMAP data. This
observational possibility also provides an experimental window for an
inflationary leptogenesis mechanism arising from large-scale parity violation.
A velocity dependent potential is induced from gravitational backreaction,
which modifies the primordial scalar angular power spectrum of density
perturbations in the CMB. This modification suppresses power of odd parity
multipoles on large scales which can be associated with the scale of a massive
right-handed neutrino.Comment: 5 pages, included new references, expanded on some calculation
Parafermionic algebras, their modules and cohomologies
We explore the Fock spaces of the parafermionic algebra introduced by H.S.
Green. Each parafermionic Fock space allows for a free minimal resolution by
graded modules of the graded 2-step nilpotent subalgebra of the parafermionic
creation operators. Such a free resolution is constructed with the help of a
classical Kostant's theorem computing Lie algebra cohomologies of the nilpotent
subalgebra with values in the parafermionic Fock space. The Euler-Poincar\'e
characteristics of the parafermionic Fock space free resolution yields some
interesting identities between Schur polynomials. Finally we briefly comment on
parabosonic and general parastatistics Fock spaces.Comment: 10 pages, talk presented at the International Workshop "Lie theory
and its applications in Physics" (17-23 June 2013, Varna, Bulgaria
Canonical Partition Functions for Parastatistical Systems of any order
A general formula for the canonical partition function for a system obeying
any statistics based on the permutation group is derived. The formula expresses
the canonical partition function in terms of sums of Schur functions. The only
hitherto known result due to Suranyi [ Phys. Rev. Lett. {\bf 65}, 2329 (1990)]
for parasystems of order two is shown to arise as a special case of our general
formula. Our results also yield all the relevant information about the
structure of the Fock spaces for parasystems.Comment: 9 pages, No figures, Revte
Born reciprocity and the 1/r potential
Many structures in nature are invariant under the transformation
(p,r)->(br,-p/b), where b is some scale factor. Born's reciprocity hypothesis
affirms that this invariance extends to the entire Hamiltonian and equations of
motion. We investigate this idea for atomic physics and galactic motion, where
one is basically dealing with a 1/r potential and the observations are very
accurate, so as to determine the scale . We find that an Hz has essentially no effect on atomic physics but
might possibly offer an explanation for galactic rotation, without invoking
dark matter.Comment: 14 pages, with 4 figures, Latex, requires epsf.tex and iop style
file
Aspects of Fractional Superstrings
We investigate some issues relating to recently proposed fractional
superstring theories with . Using the factorization
approach of Gepner and Qiu, we systematically rederive the partition functions
of the and theories and examine their spacetime supersymmetry.
Generalized GSO projection operators for the model are found. Uniqueness
of the twist field, , as source of spacetime fermions is
demonstrated. Last, we derive a linear (rather than quadratic) relationship
between the required conformal anomaly and the conformal dimension of the
supercurrent ghost.Comment: 36 pages, CALT-68-1756 Revisions to match form to appear in Comm.
Math. Phys. Use standard TeX. Derivation of affine partition functions
related to models is now shown. References Update
The clinical and biological significance of HER2 over-expression in breast ductal carcinoma in situ: a large study from a single institution
© 2019, Cancer Research UK. Background: Previous studies have reported up to 50% of ductal carcinoma in situ (DCIS), is HER2 positive, but the frequency of HER2-positive invasive breast cancer (IBC) is lower. The aim of this study is to characterise HER2 status in DCIS and assess its prognostic value. Methods: HER2 status was evaluated in a large series of DCIS (n = 868), including pure DCIS and DCIS associated with IBC, prepared as tissue microarrays (TMAs). HER2 status was assessed using immunohistochemistry (IHC) and chromogenic in situ hybridisation (CISH). Results: In pure DCIS, HER2 protein was over-expressed in 9% of DCIS (3+), whereas 15% were HER2 equivocal (2+). Using CISH, the final HER2 status was positive in 20%. In mixed DCIS, HER2 amplification of the DCIS component was detected in 15% with amplification in the invasive component of only 12%. HER2-positive DCIS was associated with features of aggressiveness (p < 0.0001) and more frequent local recurrence (p = 0.03). On multivariate analysis, combined HER2+/Ki67+ profile was an independent predictor of local recurrence (p = 0.006). Conclusions: The frequency of HER2 positivity in DCIS is comparable to IBC- and HER2-positive DCIS is associated with features of poor prognosis. The majority of HER2 over-expression in DCIS is driven by gene amplification
PP-Wave Light-Cone Free String Field Theory at Finite Temperature
In this paper, a real-time formulation of light-cone pp-wave string field
theory at finite temperature is presented. This is achieved by developing the
thermo field dynamics (TFD) formalism in a second quantized string scenario.
The equilibrirum thermodynamic quantities for a pp-wave ideal string gas are
derived directly from expectation values on the second quantized string thermal
vacuum. Also, we derive the real-time thermal pp-wave closed string propagator.
In the flat space limit it is shown that this propagator can be written in
terms of Theta functions, exactly as the zero temperature one. At the end, we
show how supestrings interactions can be introduced, making this approach
suitable to study the BMN dictionary at finite temperature.Comment: 27 pages, revtex
Topological Defects on Fluctuating Surfaces: General Properties and the Kosterlitz-Thouless Transition
We investigate the Kosterlitz-Thouless transition for hexatic order on a free
fluctuating membrane and derive both a Coulomb gas and a sine-Gordon
Hamiltonian to describe it. The Coulomb-gas Hamiltonian includes charge
densities arising from disclinations and from Gaussian curvature. There is an
interaction coupling the difference between these two densities, whose strength
is determined by the hexatic rigidity, and an interaction coupling Gaussian
curvature densities arising from the Liouville Hamiltonian resulting from the
imposition of a covariant cutoff. In the sine-Gordon Hamiltonian, there is a
linear coupling between a scalar field and the Gaussian curvature. We discuss
gauge-invariant correlation function for hexatic order and the dielectric
constant of the Coulomb gas. We also derive renormalization group recursion
relations that predict a transition with decreasing bending rigidity .Comment: REVTEX, 45 pages with 11 postscript figures compressed using uufiles.
Accepted for publication in Phys. Rev.
The Supersymmetric Standard Models with Decay and Stable Dark Matters
We propose two supersymmetric Standard Models (SMs) with decaying and stable
dark matter (DM) particles. To explain the SM fermion masses and mixings and
have a heavy decay DM particle S, we consider the Froggatt-Nielsen mechanism by
introducing an anomalous U(1)_X gauge symmetry. Around the string scale, the
U(1)_X gauge symmetry is broken down to a Z_2 symmetry under which S is odd
while all the SM particles are even. S obtains a vacuum expectation value
around the TeV scale, and then it can three-body decay dominantly to the
second/third family of the SM leptons in Model I and to the first family of the
SM leptons in Model II. Choosing a benchmark point in the constrained minimal
supersymmetric SM with exact R parity, we show that the lightest neutralino DM
is consistent with the CDMS II experiment. Considering S three-body decay and
choosing suitable parameters, we show that the PAMELA and Fermi-LAT experiments
and the PAMELA and ATIC experiments can be explained in Model I and Model II,
respectively.Comment: RevTex4, 26 pages, 6 figures, references added, version to appear in
EPJ
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