1,423 research outputs found
Generating Erler-Schnabl-type Solution for Tachyon Vacuum in Cubic Superstring Field Theory
We study a new set of identity-based solutions to analyze the problem of
tachyon condensation in open bosonic string field theory and cubic superstring
field theory. Even though these identity-based solutions seem to be trivial, it
turns out that after performing a suitable gauge transformation, we are left
with the known Erler-Schnabl-type solutions which correctly reproduce the value
of the D-brane tension. This result shows explicitly that how a seemingly
trivial solution can generate a non-trivial configuration which precisely
represents to the tachyon vacuum.Comment: 22 pages, references added, appendix added, 2 subsections adde
On Gauge Equivalence of Tachyon Solutions in Cubic Neveu-Schwarz String Field Theory
Simple analytic solution to cubic Neveu-Schwarz String Field Theory including
the sector is presented. This solution is an analog of the
Erler-Schnabl solution for bosonic case and one of the authors solution for the
pure case. Gauge transformations of the new solution to others known
solutions for the string tachyon condensation are constructed explicitly.
This gauge equivalence manifestly supports the early observed fact that these
solutions have the same value of the action density.Comment: 8 pages, LaTe
Triviality and the Precision Bound on the Higgs Mass
The triviality of the scalar sector of the standard one-doublet Higgs model
implies that this model is only an effective low-energy theory valid below some
cut-off scale Lambda. For a heavy higgs this scale must be relatively low (10
TeV or less). Additional interactions coming from the underlying theory, and
suppressed by the scale Lambda, give rise to model-dependent corrections to
precisely measured electroweak quantities. Dimension six operators arising from
the underlying physics naturally contribute to the S and T parameters, and
their effects should be included in a global fit to the precision data that
determines any limit on the Higgs mass. Using dimensional analysis, we estimate
the expected size of these corrections in a custodially-symmetric
strongly-interacting underlying theory. Taking these operators' coefficients to
be of natural size gives sufficiently large contributions to the T parameter to
reconcile Higgs masses as large as 400-500 GeV with the precision data.Comment: 9 pages, 3 epsf figures include
Gastric Cancer in the Setting of Persistently Elevated Human Chorionic Gonadotropin: A Case Report
A 35-year-old woman presented to the emergency room for the evaluation of failed surgical and medical management of a suspected ectopic pregnancy. When imaging studies were performed, she had lymphadenopathy and diffuse sclerosis of the osseous framework. Multiple biopsies were performed and revealed poorly differentiated metastatic carcinoma with signet ring features. Esophagogastroduodenoscopy confirmed the findings of a Stage IV gastric adenocarcinoma. Signs and symptoms of gastric carcinoma are vague. However, to our knowledge, an elevation in human chorionic gonadotropin (hCG) is not an associated finding. Persistence of hCG has many causes from abnormal pregnancy to menopause and other forms of cancer
The Fourth SM Family Neutrino at Future Linear Colliders
It is known that Flavor Democracy favors the existence of the fourth standard
model (SM) family. In order to give nonzero masses for the first three family
fermions Flavor Democracy has to be slightly broken. A parametrization for
democracy breaking, which gives the correct values for fundamental fermion
masses and, at the same time, predicts quark and lepton CKM matrices in a good
agreement with the experimental data, is proposed. The pair productions of the
fourth SM family Dirac and Majorana neutrinos at future
linear colliders with GeV, 1 TeV and 3 TeV are considered. The
cross section for the process
and the branching ratios for possible decay modes of the both neutrinos are
determined. The decays of the fourth family neutrinos into muon channels
provide cleanest signature at
colliders. Meanwhile, in our parametrization this channel is
dominant. bosons produced in decays of the fourth family neutrinos will be
seen in detector as either di-jets or isolated leptons. As an example we
consider the production of 200 GeV mass fourth family neutrinos at
GeV linear colliders by taking into account di-muon plus
four-jet events as signatures.Comment: 16 pages, 3 figures, 10 table
Misfits in Skyrme-Hartree-Fock
We address very briefly five critical points in the context of the
Skyrme-Hartree-Fock (SHF) scheme: 1) the impossibility to consider it as an
interaction, 2) a possible inconsistency of correlation corrections as, e.g.,
the center-of-mass correction, 3) problems to describe the giant dipole
resonance (GDR) simultaneously in light and heavy nuclei, 4) deficiencies in
the extrapolation of binding energies to super-heavy elements (SHE), and 5) a
yet inappropriate trend in fission life-times when going to the heaviest SHE.
While the first two points have more a formal bias, the other three points have
practical implications and wait for solution.Comment: 9 pages, 4 figure
Taming boundary condition changing operator anomalies with the tachyon vacuum
Motivated by the appearance of associativity anomalies in the context of superstring field theory, we give a generalized solution built from boundary condition changing operators which can be associated to a generic tachyon vacuum in the KBc subalgebra of the Okawa form. We articulate sufficient conditions on the choice of tachyon vacuum to ensure that ambiguous products do not appear in the equations of motion
Recent Developments in Precision Electroweak Physics
Developments in precision electroweak physics in the two years since the
symposium are briefly summarized.Comment: Update on recent developments, prepared for the publication of the
Proceedings of Alberto Sirlin Symposium, New York University, October 2000.
10 pages, 1 figur
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