78,873 research outputs found
QCD CORRECTIONS TO THE H+ -->t anti-b decay within the minimal supersymmetric standard model
I present the results of the QCD corrections to the H+ --> t anti-b decay
within the minimal supersymmetric standard model, if gluinos and scalar quarks
are taken within the relevant loop diagram. I include the mixing of the scalar
partners of the left- and right-handed top quark, which is proportional to the
top quark mass. The standard corrections via gluons and quarks are about +8%
for a charged Higgs mass of 300 GeV and about -11% for a Higgs mass of 800 GeV.
I show that the standard corrections are diminished or enhanced by a
non-negligible amount for certain values of the supersymmetric parameter space.
I also obtain sign changes.Comment: UQAM-PHE-94/03, 5 pages, plain tex, 5 figures not included, available
under request via mail or fa
Primordial hadrosynthesis in the Little Bang
The present status of soft hadron production in high energy heavy-ion
collisions is summarized. In spite of strong evidence for extensive dynamical
evolution and collective expansion of the fireball before freeze-out I argue
that its chemical composition is hardly changed by hadronic final state
interactions. The measured hadron yields thus reflect the primordial conditions
at hadronization. The observed production pattern is consistent with
statistical hadronization at the Hagedorn temperature from a state of
uncorrelated, color deconfined quarks and antiquarks, but requires non-trivial
chemical evolution of the fireball in a prehadronic (presumably QGP) stage
before hadron formation.Comment: 10 pages LaTeX, including 5 figures. Invited overview talk given at
Quark Matter '99, Torino, Italy, May 10-15, 1999. To appear in Nucl. Phys.
Inhomogeneous condensates in the parity doublet model
Within the parity doublet model coupled to the linear sigma model including
vector mesons it is possible to describe vacuum properties of the low energy
mesons and to achieve nuclear saturation at nonzero density. Motivated by
recent studies we investigate the emergence of inhomogeneous condensation in
the parity doublet model. As a first step the chiral density wave (CDW) is con-
sidered, which allows for a straightforward investigation of inhomogeneous
condensation. As a result it is still possible to have a homogeneous ground
state of nuclear matter, but at larger baryon chemical potential the CDW is
favored with respect to the homogeneous phase.Comment: 7 pages, 4 figure
Strange and Multi-Strange Particle Production in P+P Collisions at =200 Gev in Star
We present measurements of the transverse momentum spectra for K0s, Lambda,
Xi and their antiparticles in p+p collisions at GeV. The
extracted mid-rapidity yields and are in agreement with previous
experiments while they have smaller statistical errors. We compare
the measured particle spectra and values to predictions from the PYTHIA
leading order pQCD model (v6.221) and see significant disagreements with the
default settings. Finally we compare the spectra to the latest calculations
from NLO pQCD and see a good agreement for the K0s, but large discrepancies
Lambda.Comment: 4 pages, Proceedings for the 40th Rencontres de Moriond (QCD), La
Thuile, March 200
Safeguarding Old and New Journal Tables for the VO: Status for Extragalactic and Radio Data
Independent of established data centers, and partly for my own research,
since 1989 I have been collecting the tabular data from over 2600 articles
concerned with radio sources and extragalactic objects in general. Optical
character recognition (OCR) was used to recover tables from 740 papers. Tables
from only 41 percent of the 2600 articles are available in the CDS or CATS
catalog collections, and only slightly better coverage is estimated for the NED
database. This fraction is not better for articles published electronically
since 2001. Both object databases (NED, SIMBAD, LEDA) as well as catalog
browsers (VizieR, CATS) need to be consulted to obtain the most complete
information on astronomical objects. More human resources at the data centers
and better collaboration between authors, referees, editors, publishers, and
data centers are required to improve data coverage and accessibility. The
current efforts within the Virtual Observatory (VO) project, to provide
retrieval and analysis tools for different types of published and archival data
stored at various sites, should be balanced by an equal effort to recover and
include large amounts of published data not currently available in this way.Comment: 11 pages, 4 figures; accepted for publication in Data Science
Journal, vol. 8 (2009), http://dsj.codataweb.org; presented at Special
Session "Astronomical Data and the Virtual Observatory" on the conference
"CODATA 21", Kiev, Ukraine, October 5-8, 200
HEGRA Observations of Galactic Sources
In this talk I will first give a summary of the observations of expected
Galactic TeV gamma-ray sources with the HEGRA CT-Sytem since the Kruger Park
Workshop in 1997. Then I will go into some detail regarding the observations of
Supernova Remnants (SNRs), especially those of Tycho's SNR and of Cas A. The
emphasis will not be on all aspects of these published data. I will rather
review the selection of these observational targets, and discuss some of the
physical implications of the results.Comment: 8 pages, 5 Postscript figures, to appear in "GeV-TeV Astrophysics:
Toward a Major Atmospheric Cherenkov Telescope VI," Snowbird, Utah (August,
1999
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