3,427 research outputs found
Realistic Gluino Axion Model Consistent with Supersymmetry Breaking at the TeV Scale
The recently proposed model of using the dynamical phase of the gluino to
solve the strong CP problem is shown to admit a specific realization in terms
of fundamental singlet superfields, such that the breaking of supersymmetry
occurs only at the TeV scale, despite the large axion scale of 10^{9} to
10^{12} GeV. Phenomenological implications are discussed.Comment: 12 pp, 2 fig
Neutrino Masses and the Gluino Axion Model
We extend the recently proposed gluino axion model to include neutrino
masses. We discuss how the canonical seesaw model and the Higgs triplet model
may be realized in this framework. In the former case, the heavy singlet
neutrinos are contained in superfields which do not have any vacuum expectation
value, whereas the gluino axion is contained in one which does. We also
construct a specific renormalizable model which realizes the mass scale
relationship , where is the axion decay constant
and is a large effective mass parameter.Comment: 8 pages, no figur
Color science of nanocrystal quantum dots for lighting and displays
Cataloged from PDF version of article.Colloidal nanocrystals of semiconductor quantum dots (QDs) are gaining prominence among the optoelectronic materials in the photonics industry. Among their many applications, their use in artificial lighting and displays has attracted special attention thanks to their high efficiency and narrow emission band, enabling spectral purity and fine tunability. By employing QDs in color-conversion LEDs, it is possible to simultaneously accomplish successful color rendition of the illuminated objects together with a good spectral overlap between the emission spectrum of the device and the sensitivity of the human eye, in addition to a warm white color, in contrast to other conventional sources such as incandescent and fluorescent lamps, and phosphor-based LEDs, which cannot achieve all of these properties at the same time. In this review, we summarize the color science of QDs for lighting and displays, and present the recent developments in QD-integrated LEDs and display research. First, we start with a general introduction to color science, photometry, and radiometry. After presenting an overview of QDs, we continue with the spectral designs of QD-integrated white LEDs that have led to efficient lighting for indoor and outdoor applications. Subsequently, we discuss QD color-conversion LEDs and displays as proof-of-concept applications - a new paradigm in artificial lighting and displays. Finally, we conclude with a summary of research opportunities and challenges along with a future outlook
Relaxation of the Dynamical Gluino Phase and Unambiguous Electric Dipole Moments
We propose a new axionic solution of the strong CP problem with a
Peccei-Quinn mechanism using the gluino rather than quarks. The spontaneous
breaking of this new global U(1) at 10^{11} GeV also generates the
supersymmetry breaking scale of 1 TeV (solving the so-called \mu problem at the
same time) and results in the MSSM (Minimal Supersymmetric Standard Model) with
R parity conservation. In this framework, electric dipole moments become
calculable without ambiguity.Comment: Typos corrected and a footnote added, 10 p
The effect of supersymmetric CP phases on Chargino-Pair Production via Drell-Yan Process at the LHC
We compute the rates for pp annihilation into chargino-pairs via Drell-Yan
process taking into account the effects of supersymmetric soft phases, at
proton-proton collider. In particular, the phase of the mu parameter gains
direct accessibility via the production of dissimilar charginos. The phases of
the trilinear soft masses do not have a significant effect on the cross
sections.Comment: 24 pages, 7 figure
High scotopic/photopic ratio white-light-emitting diodes integrated with semiconductor nanophosphors of colloidal quantum dots
Cataloged from PDF version of article.We propose and demonstrate single-chip white-light-emitting diodes (WLEDs) integrated with semiconductor nanophosphors of colloidal quantum dots for high scotopic/photopic (S/P) ratio. These color conversion WLEDs achieve S/P ratios over 3.00, which exceeds the current limit of 2.50 in common lighting technologies, while sustaining sufficient levels of color rendering index. (C) 2011 Optical Society of Americ
Computational study of power conversion and luminous efficiency performance for semiconductor quantum dot nanophosphors on light-emitting diodes
Cataloged from PDF version of article.We present power conversion efficiency (PCE) and luminous efficiency (LE) performance levels of high photometric quality white LEDs integrated with quantum dots (QDs) achieving an averaged color rendering index of >= 90 (with R9 at least 70), a luminous efficacy of optical radiation of >= 380 lm/W-opt a correlated color temperature of <= 4000 K, and a chromaticity difference dC <0.0054. We computationally find that the device LE levels of 100, 150, and 200 lm/W-elect can be achieved with QD quantum efficiency of 43%, 61%, and 80% in film, respectively, using state-of-the-art blue LED chips (81.3% PCE). Furthermore, our computational analyses suggest that QD-LEDs can be both photometrically and electrically more efficient than phosphor based LEDs when state-of-the-art QDs are used. (C) 2012 Optical Society of Americ
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