3,242 research outputs found
SUSY-QCD Effect on Top-Charm Associated Production at Linear Collider
We evaluate the contribution of SUSY-QCD to top-charm associated production
at next generation linear colliders. Our results show that the production cross
section of the process could be as large as 0.1
fb, which is larger than the prediction of the SM by a factor of .Comment: version to appear in PR
Luttinger Liquid Instability in the One Dimensional t-J Model
We study the t-J model in one dimension by numerically projecting the true
ground state from a Luttinger liquid trial wave function. We find the model
exhibits Luttinger liquid behavior for most of the phase diagram in which
interaction strength and density are varied. However at small densities and
high interaction strengths a new phase with a gap to spin excitations and
enhanced superconducting correlations is found. We show this phase is a
Luther-Emery liquid and study its correlation functions.Comment: REVTEX, 11 pages. 4 Figures available on request from
[email protected]
Guest Editorial Cardiovascular Health Informatics: Risk Screening and Intervention
Despite enormous efforts to prevent cardiovascular disease (CVD) in the past, it remains the leading cause of death in most countries worldwide. Around two-thirds of these deaths are due to acute events, which frequently occur suddenly and are often fatal beforemedical care can be given. New strategies for screening and early intervening CVD, in addition to the conventional methods, are therefore needed in order to provide personalized and pervasive healthcare. In this special issue, selected emerging technologies in health informatics for screening and intervening CVDs are reported. These papers include reviews or original contributions on 1) new potential genetic biomarkers for screening CVD outcomes and high-throughput techniques for mining genomic data; 2) new imaging techniques for obtaining faster and higher resolution images of cardiovascular imaging biomarkers such as the cardiac chambers and atherosclerotic plaques in coronary arteries, as well as possible automatic segmentation, identification, or fusion algorithms; 3) new physiological biomarkers and novel wearable and home healthcare technologies for monitoring them in daily lives; 4) new personalized prediction models of plaque formation and progression or CVD outcomes; and 5) quantifiable indices and wearable systems to measure them for early intervention of CVD through lifestyle changes. It is hoped that the proposed technologies and systems covered in this special issue can result in improved CVD management and treatment at the point of need, offering a better quality of life to the patient
Bound state solutions of the Dirac-Rosen-Morse potential with spin and pseudospin symmetry
The energy spectra and the corresponding two- component spinor wavefunctions
of the Dirac equation for the Rosen-Morse potential with spin and pseudospin
symmetry are obtained. The wave ( state) solutions for this
problem are obtained by using the basic concept of the supersymmetric quantum
mechanics approach and function analysis (standard approach) in the
calculations. Under the spin symmetry and pseudospin symmetry, the energy
equation and the corresponding two-component spinor wavefunctions for this
potential and other special types of this potential are obtained. Extension of
this result to state is suggested.Comment: 18 page
Spin-charge separation at small lengthscales in the 2D t-J model
We consider projected wavefunctions for the 2D model. For various
wavefunctions, including correlated Fermi-liquid and Luttinger-type
wavefunctions we present the static charge-charge and spin-spin structure
factors. Comparison with recent results from a high-temperature expansion by
Putikka {\it et al.} indicates spin-charge separation at small lengthscales.Comment: REVTEX, 5 pages, 5 figures hardcopies availabl
Variational state based on the Bethe ansatz solution and a correlated singlet liquid state in the one-dimensional t-J model
The one-dimensional t-J model is investigated by the variational Monte Carlo
method. A variational wave function based on the Bethe ansatz solution is newly
proposed, where the spin-charge separation is realized, and a long-range
correlation factor of Jastrow-type is included. In most regions of the phase
diagram, this wave function provides an excellent description of the
ground-state properties characterized as a Tomonaga-Luttinger liquid; Both of
the amplitude and exponent of correlation functions are correctly reproduced.
For the spin-gap phase, another trial state of correlated singlet pairs with a
Jastrow factor is introduced. This wave function shows generalized Luther-Emery
liquid behavior, exhibiting enhanced superconducting correlations and
exponential decay of the spin correlation function. Using these two variational
wave functions, the whole phase diagram is determined. In addition, relations
between the correlation exponent and variational parameters in the trial
functions are derived.Comment: REVTeX 3.0, 27 pages. 7 figures available upon request
([email protected]). To be published in Phys. Rev. B 5
From antiferromagnetism to d-wave superconductivity in the 2D t-J model
We have found that the two dimensional t-J model, for the physical parameter
range J/t = 0.4 reproduces the main experimental qualitative features of
High-Tc copper oxide superconductors: d-wave superconducting correlations are
strongly enhanced upon small doping and clear evidence of off diagonal long
range order is found at the optimal doping \delta ~ 0.15. On the other hand
antiferromagnetic long range order, clearly present at zero hole doping, is
suppressed at small hole density with clear absence of antiferromagnetism at
\delta >~ 0.1.Comment: 4 pages, 5 figure
Pulsations driven by the Δ-mechanism in post-merger remnants: First results
Helium-rich subdwarfs are a rare subclass of hot subdwarf stars which constitute a small and inhomogeneous group showing varying degrees of helium enrichment. Only one star, LS IV Âș14 116 has been found to show multiperiodic luminosity variations. The variability of LS IV Âș14 116 has been explained as the consequence of nonradial g-mode oscillations, whose excitation is difficult to understand within the frame of the standard Îș-mechanism driving pulsations in sdBV stars. In a recent study, we have proposed that the pulsations of LS IV Âș14 116 might be driven through the Δ-mechanism acting in unstable He-burning zones in the interior of the star, that appear before the quiescent He-burning phase. One of the few accepted scenarios for the formation of He-rich subdwarfs is the merger of two He-core white dwarfs. As part of this project, we present a study of the Δ-mechanism in post-merger remnants, and discuss the results in the light of the pulsations exhibited by LS IV Âș14 116.Facultad de Ciencias AstronĂłmicas y GeofĂsica
Virtual Effects of Split SUSY in Higgs Productions at Linear Colliders
In split supersymmetry the gauginos and higgsinos are the only supersymmetric
particles possibly accessible at foreseeable colliders like the CERN Large
Hadron Collider (LHC) and the International Linear Collider (ILC). In order to
account for the cosmic dark matter measured by WMAP, these gauginos and
higgsinos are stringently constrained and could be explored at the colliders
through their direct productions and/or virtual effects in some processes. The
clean environment and high luminosity of the ILC render the virtual effects of
percent level meaningful in unraveling the new physics effects. In this work we
assume split supersymmetry and calculate the virtual effects of the
WMAP-allowed gauginos and higgsinos in Higgs productions e+e- -> Z h and e+e-
-> \nu_e \bar_\nu_e h through WW fusion at the ILC. We find that the production
cross section of e+e- -> Zh can be altered by a few percent in some part of the
WMAP-allowed parameter space, while the correction to the WW-fusion process
e+e- -> \nu_e \bar_\nu_e h is below 1%. Such virtual effects are correlated
with the cross sections of chargino pair productions and can offer
complementary information in probing split supersymmetry at the colliders.Comment: more discussions added (7 pages, 10 figs
Is the first radial excitation of ?
We present a quantitative analysis of the observed by
SELEX mainly focusing on the assumption that is the first
radial excitation of the ground state . By solving the
instantaneous Bethe-Salpeter equation, we obtain the mass MeV for
the first excited state, which is about 26 MeV heavier than the experimental
value MeV. By means of PCAC and low-energy theorem we calculate
the transition matrix elements and obtain the decay widths:
MeV, MeV, and
the ratio as well. This ratio is quite different from the
SELEX data . The summed decay width of those three channels is
approximately 21.7 MeV, already larger than the observed bound for the full
width ( MeV). Furthermore, assuming is state,
we also explore the possibility of wave mixing to explain the SELEX
observation. Based on our analysis, we suspect that it is too early to conclude
that is the first radial excitation of the ground
state . More precise measurements of the relative ratios and
the total decay width are urgently required especially for wave mixing.Comment: 12 pages, 8 figure
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