3,141 research outputs found
Comment on `Glassy Transition in a Disordered Model for the RNA Secondary Structure'
In cond-mat/9907125 the low-temperature behavior of a model for RNA secondary
structure was studied. It is claimed that the model exhibits a breaking of the
replica symmetry, since the width of the distribution P(q) of overlaps may
converge to a finite value at T=0. The authors used an exact enumeration method
to obtain all ground states for a given RNA sequence. Because of the
exponential growing degeneracy, only sequences up to length L=256 could be
studied.
Here it is shown that, in contrast to the previous results, by going to much
larger sizes as L=2000 the variance coverges towards zero, i.e. P(q) is a
delta-function in the thermodynamic limit.Comment: completely rewritten, comment to cond-mat/9907125 (PRL 84, 2026
Tennessee-Tombigbee industrial siting project: A study of physical and environmental factors of potential industrial sites
There are no author-identified significant results in this report
New Mechanism of Flavor Symmetry Breaking from Supersymmetric Strong Dynamics
We present a class of supersymmetric models in which flavor symmetries are
broken dynamically, by a set of composite flavon fields. The strong dynamics
that is responsible for confinement in the flavor sector also drives flavor
symmetry breaking vacuum expectation values, as a consequence of a
quantum-deformed moduli space. Yukawa couplings result as a power series in the
ratio of the confinement to Planck scale, and the fermion mass hierarchy
depends on the differing number of preons in different flavor symmetry-breaking
operators. We present viable non-Abelian and Abelian flavor models that
incorporate this mechanism.Comment: 24 pp. LaTe
The MSSM fine tuning problem: a way out
As is well known, electroweak breaking in the MSSM requires substantial
fine-tuning, mainly due to the smallness of the tree-level Higgs quartic
coupling, lambda_tree. Hence the fine tuning is efficiently reduced in
supersymmetric models with larger lambda_tree, as happens naturally when the
breaking of SUSY occurs at a low scale (not far from the TeV). We show, in
general and with specific examples, that a dramatic improvement of the fine
tuning (so that there is virtually no fine-tuning) is indeed a very common
feature of these scenarios for wide ranges of tan(beta) and the Higgs mass
(which can be as large as several hundred GeV if desired, but this is not
necessary). The supersymmetric flavour problems are also drastically improved
due to the absence of RG cross-talk between soft mass parameters.Comment: 28 pages, 9 PS figures, LaTeX Published versio
The enormous outer Galaxy HII region CTB 102
We present new radio recombination line observations of the previously
unstudied HII region CTB 102. Line parameters are extracted and physical
parameters describing the gas are calculated. We estimate the distance to CTB
102 to be 4.3 kpc. Through comparisons with HI and 1.42 GHz radio continuum
data, we estimate the size of CTB 102 to be 100-130 pc, making it one of the
largest HII regions known, comparable to the W4 complex. A stellar wind blown
bubble model is presented as the best explanation for the observed morphology,
size and velocities.Comment: 26 pages, 8 figures. Accepted for publication by The Astrophysical
Journa
Reply to the Comment on `Glassy Transition in a Disordered Model for the RNA Secondary Structure'
We reply to the Comment by Hartmann (cond-mat/9908132) on our paper Phys.
Rev. Lett. 84 (2000) 2026 (also cond-mat/9907125).Comment: 1 page, no figures. Accepted for publication in Phys. Rev. Let
Discovery potential for a charged Higgs boson decaying in the chargino-neutralino channel of the ATLAS detector at the LHC
We have investigated charged Higgs boson production via the gluon-bottom
quark mode, gb -> tH+, followed by its decay into a chargino and a neutralino.
The calculations are based on masses and couplings given by the Minimal
Supersymmetric Standard Model (MSSM) for a specific choice of MSSM parameters.
The signature of the signal is characterized by three hard leptons, a
substantial missing transverse energy due to the decay of the neutralino and
the chargino and three hard jets from the hadronic decay of the top quark. The
possibility of detecting the signal over the Standard Model (SM) and non-SM
backgrounds was studied for a set of tanBeta and mA. The existence of 5-sigma
confidence level regions for H+ discovery at integrated luminosities of 100
fb-1 and 300 fb-1 is demonstrated, which cover also the intermediate region 4 <
tanBeta < 10 where H+ decays to SM particles cannot be used for H+ discovery
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