90,978 research outputs found
Identification of large masses of citrus fruit and rice fields in eastern Spain
There are no author-identified significant results in this report
The SuperWorlds of SU(5) and SU(5)xU(1): A Critical Assessment and Overview
We present an overview of the simplest supergravity models which enforce
radiative breaking of the electroweak symmetry, namely the minimal
supergravity model and the class of string-inspired/derived supergravity models
based on the flipped structure supplemented by a minimal set
of additional matter representations such that unification occurs at the string
scale (\sim10^{18}\GeV). These models can be fully parametrized in terms of
the top-quark mass, the ratio , and three supersymmetry
breaking parameters (). The latter are chosen in the minimal
model such that the stringent constraints from proton decay and
cosmology are satisfied. In the flipped case we consider two
string-inspired supersymmetry breaking scenaria: no-scale
supergravity and a dilaton-induced supersymmetry breaking scenario. Both imply
universal soft supersymmetry breaking parameters: and
m_0=\coeff{1}{\sqrt{3}}m_{1/2}, A=-m_{1/2} respectively. We present a
comparative study of the sparticle and Higgs spectra of both flipped
models and the minimal model and conclude that all can be partially
probed at the Tevatron and LEPII (and the flipped models at HERA too). In both
flipped cases there is a more constrained version which allows to
determine in terms of and which leads to much
sharper and readily accessible experimental predictions. We also discuss the
prospects for indirect experimental detection: a non-trivial fraction of the
parameter space of the flipped models is in conflict with the present
experimental allowed range for the rare decay mode, and the
one-loop electroweak radiative corrections imply the 90\% CL upper boundComment: CERN-TH.6934/93, CTP-TAMU-34/93, LaTeX, 58 pages, 20 embedded
figures. Complete ps file (~12000 blocks, 5.24MB) available via anonymous ftp
from site tamsun.tamu.edu in directory incoming, filename: CTP-TAMU-34-93.p
Understanding the Mass-Radius Relation for Sub-Neptunes: Radius as a Proxy for Composition
Transiting planet surveys like Kepler have provided a wealth of information
on the distribution of planetary radii, particularly for the new populations of
super-Earth and sub-Neptune sized planets. In order to aid in the physical
interpretation of these radii, we compute model radii for low-mass rocky
planets with hydrogen-helium envelopes. We provide model radii for planets 1-20
Earth masses, with envelope fractions from 0.01-20%, levels of irradiation
0.1-1000x Earth's, and ages from 100 Myr to 10 Gyr. In addition we provide
simple analytic fits that summarize how radius depends on each of these
parameters. Most importantly, we show that at fixed composition, radii show
little dependence on mass for planets with more than ~1% of their mass in their
envelope. Consequently, planetary radius is to first order a proxy for
planetary composition for Neptune and sub-Neptune sized planets. We recast the
observed mass-radius relationship as a mass-composition relationship and
discuss it in light of traditional core accretion theory. We discuss the
transition from rocky super-Earths to sub-Neptune planets with large volatile
envelopes. We suggest 1.75 Earth radii as a physically motivated dividing line
between these two populations of planets. Finally, we discuss these results in
light of the observed radius occurrence distribution found by Kepler.Comment: 17 pages, 9 figures, 7 tables, submitted to Ap
A study of stopping power in nuclear reactions at intermediate energies
We show a systematic experimental study based on INDRA data of the stopping
power in central symmetric nuclear reactions. Total mass of the systems goes
from 80 to 400 nucleons while the incident energy range is from 12 AMeV to 100
AMeV. The role of isospin diffusion at 32 and 45 MeV/nucleon with 124,136Xe
projectiles on 112,124Sn targets performed at GANIL is also discussed. Results
suggest a strong memory of the entrance channel above 20 AMeV/A (nuclear
transparency) and, as such, constitute valuable tests of the microscopic
transport models.Comment: 7 pages, 3 figures, Proceedings of International Workshop on
Multifragmentation and Related Topics (IWM 2009), Catania, Italy, 4 Nov-7 Nov
200
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