3,358 research outputs found
Supersymmetric SU(3) X U(1) Gauge Model: Higgs Structure at the Electroweak Scale
We consider a supersymmetric version of the recently proposed SU(3) X U(1)
extended gauge model. We show that it is possible to have only two Higgs
doublets at the SU(2) X U(1) energy scale but they are not those of the minimal
supersymmetric standard model. In particular, the upper bound on the lightest
scalar boson of this model is at tree level and goes up
to 189 GeV after radiative corrections.Comment: 9 pages, Univ. of California, Riverside Report No. UCRHEP-T111, June
199
Tetramethylenedisulfotetramine
Tetramethylenedisulfotetramine (CAS 80-12-6), commonly referred to as TETS, was first synthesized in 1933 as a condensation product of sulfamide and formaldehyde. TETS was subsequently used as a rodenticide until banned worldwide in 1991. TETS is, however, still available illegally, primarily in rural China, and is responsible for accidental and intentional poisonings that cause a significant number of human deaths annually. TETS induces convulsive seizures mediated by antagonism of Îł-amino-butyric acid (GABA)-mediated chloride channels. There are no known antidotes for TETS poisoning, and in cases of severe TETS intoxication that progress to status epilepticus, prognosis is poor even with aggressive anti-convulsant treatment
Spectra of massive QCD dirac operators from random matrix theory: All three chiral symmetry breaking patterns
The microscopic spectral eigenvalue correlations of QCD Dirac operators in the presence of dynamical fermions are calculated within the framework of Random Matrix Theory (RMT). Our approach treats the low-energy correlation functions of all three chiral symmetry breaking patterns (labeled by the Dyson index ÎČ = 1, 2 and 4) on the same footing, offering a unifying description of massive QCD Dirac spectra. RMT universality is explicitly proven for all three symmetry classes and the results are compared to the available lattice data for ÎČ = 4
Unifiable Supersymmetric Left-Right Model with E_6 Particle Content
A new supersymmetric gauge model is proposed with particle content chosen
only from the 27 and 27* representations of E_6. The gauge symmetry SU(3) X
SU(2)_L X SU(2)_R X U(1) is realized at the TeV energy scale and the gauge
couplings converge to a single value at around 10^{16} GeV. A discrete Z_4 X
Z_2 symmetry leads to a generalized definition of lepton number and ensures the
absence of tree-level flavor-changing neutral-current interactions at the
electroweak energy scale.Comment: 12 pages (1 figure not included), UCRHEP-T129 (July 1994
Neutrino decay as a possible interpretation to the MiniBooNE observation with unparticle scenario
In a new measurement on neutrino oscillation , the
MiniBooNE Collaboration observes an excess of electron-like events at low
energy and the phenomenon may demand an explanation which obviously is beyond
the oscillation picuture. We propose that heavier neutrino decaying
into a lighter one via the transition process
where denotes any light products, could be a natural mechanism. The
theoretical model we employ here is the unparticle scenario established by
Georgi. We have studied two particular modes \nu_\mu\to \nu_e+\Un and
. Unfortunately, the number coming out from
the computation is too small to explain the observation. Moreover, our results
are consistent with the cosmology constraint on the neutrino lifetime and the
theoretical estimation made by other groups, therefore we can conclude that
even though neutrino decay seems plausible in this case, it indeed cannot be
the source of the peak at lower energy observed by the MiniBooNE collaboration
and there should be other mechanisms responsible for the phenomenon.Comment: 14 pages, conclusions are changed; published version for EPJ
Discrete symmetries and isosinglet quarks in low-energy supersymmetry
Many extensions of the minimal supersymmetric standard model contain
superfields for quarks which are singlets under weak isospin with electric
charge -1/3. We explore the possibility that such isosinglet quarks have low or
intermediate scale masses, but do not mediate rapid proton decay because of a
discrete symmetry. By imposing the discrete gauge anomaly cancellation
conditions, we show that the simplest way to achieve this is to extend the Z_3
"baryon parity" of Ibanez and Ross to the isosinglet quark superfields. This
can be done in three distinct ways. This strategy is not consistent with grand
unification with a simple gauge group, but may find a natural place in
superstring-inspired models, for example. An interesting feature of this
scenario is that proton decay is absolutely forbidden.Comment: 13 pages, MIT-CTP-2345, NUB-3097-94T
The flow of plasma in the solar terrestrial environment
The overall goal of our NASA Theory Program was to study the coupling, time delays, and feedback mechanisms between the various regions of the solar-terrestrial system in a self-consistent, quantitative manner. To accomplish this goal, it will eventually be necessary to have time-dependent macroscopic models of the different regions of the solar-terrestrial system and we are continually working toward this goal. However, with the funding from this NASA program, we concentrated on the near-earth plasma environment, including the ionosphere, the plasmasphere, and the polar wind. In this area, we developed unique global models that allowed us to study the coupling between the different regions. These results are highlighted in the next section. Another important aspect of our NASA Theory Program concerned the effect that localized 'structure' had on the macroscopic flow in the ionosphere, plasmasphere, thermosphere, and polar wind. The localized structure can be created by structured magnetospheric inputs (i.e., structured plasma convection, particle precipitation or Birkland current patterns) or time variations in these input due to storms and substorms. Also, some of the plasma flows that we predicted with our macroscopic models could be unstable, and another one of our goals was to examine the stability of our predicted flows. Because time-dependent, three-dimensional numerical models of the solar-terrestrial environment generally require extensive computer resources, they are usually based on relatively simple mathematical formulations (i.e., simple MHD or hydrodynamic formulations). Therefore, another goal of our NASA Theory Program was to study the conditions under which various mathematical formulations can be applied to specific solar-terrestrial regions. This could involve a detailed comparison of kinetic, semi-kinetic, and hydrodynamic predictions for a given polar wind scenario or it could involve the comparison of a small-scale particle-in-cell (PIC) simulation of a plasma expansion event with a similar macroscopic expansion event. The different mathematical formulations have different strengths and weaknesses and a careful comparison of model predictions for similar geophysical situations provides insight into when the various models can be used with confidence
Universal and non-universal behavior in Dirac spectra
We have computed ensembles of complete spectra of the staggered Dirac
operator using four-dimensional SU(2) gauge fields, both in the quenched
approximation and with dynamical fermions. To identify universal features in
the Dirac spectrum, we compare the lattice data with predictions from chiral
random matrix theory for the distribution of the low-lying eigenvalues. Good
agreement is found up to some limiting energy, the so-called Thouless energy,
above which random matrix theory no longer applies. We determine the dependence
of the Thouless energy on the simulation parameters using the scalar
susceptibility and the number variance.Comment: LATTICE98(confine), 9 pages, 11 figure
More on String Breaking in the 3D Abelian Higgs Model: the Photon Propagator
We study the Landau gauge photon propagator in the three--dimensional Abelian
Higgs model with compact gauge field and fundamentally charged matter in the
London limit. The total gauge field is split into singular and regular parts.
On the confinement side of the string breaking crossover the momentum
dependence of the total propagator is characterized by an anomalous dimension
similarly to 3D compact QED. At the crossover and throughout the Higgs region
the anomalous dimension disappears. This result perfectly agrees with recent
observations that the monopole--antimonopole plasma leads to nonzero anomalous
dimension and the presence of the matter fields causes monopole pairing into
dipole bound states. The Yukawa mass characterizing the propagator part from
regular gauge fields is non-vanishing at the Higgs side and coincides with the
mass found for the total propagator. The regular gauge field without anomalous
dimension becomes massless at the crossover and in the confinement region.Comment: 12 pages, 11 figures, LaTeX2
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