45 research outputs found
The production of a non-homogeneous classical pion field and the distribution of the neutral and charged pions
The probability distribution as a function of the ratio
of the neutral to total multiplicities is calculated for the
classical pion fields quickly varying in space and time.Comment: 6 pages, 1 .eps figure, using epsfig, submitted to Phys.Let
On SUSY GUTs with a degenerate Higgs mass matrix
Certain supersymmetric grand unified models predict that the coefficients of
the quadratic terms in the MSSM Higgs potential should be degenerate at the GUT
scale. We discuss some examples for such models, and we analyse the
implications of this peculiar condition of a GUT-scale degenerate Higgs mass
matrix for low-scale MSSM phenomenology. To this end we explore the parameter
space which is consistent with existing experimental constraints by means of a
Markov Chain Monte Carlo analysis.Comment: 31 pages, 27 figures; v2: typos correcte
Viscosity Sum Rules at Large Scattering Lengths
We use the operator product expansion (OPE) and dispersion relations to
obtain new model-independent "Borel-resummed" sum rules for both shear and bulk
viscosity of many-body systems of spin-1/2 fermions with predominantly short
range S-wave interactions. These sum rules relate Gaussian weights of the
frequency-dependent viscosities to the Tan contact parameter C(a). Our results
are valid for arbitrary values of the scattering length a, but receive small
corrections from operators of dimension larger than 5 in the OPE, and can be
used to study transport properties in the vicinity of the infinite scattering
length fixed point. In particular, we find that the exact dependence of the
shear viscosity sum rule on scattering length is controlled by the function
C(a). The sum rules that we obtain depend on a frequency scale w that can be
optimized to maximize their overlap with low-energy data
Axion-like-particle search with high-intensity lasers
We study ALP-photon-conversion within strong inhomogeneous electromagnetic
fields as provided by contemporary high-intensity laser systems. We observe
that probe photons traversing the focal spot of a superposition of Gaussian
beams of a single high-intensity laser at fundamental and frequency-doubled
mode can experience a frequency shift due to their intermittent propagation as
axion-like-particles. This process is strongly peaked for resonant masses on
the order of the involved laser frequencies. Purely laser-based experiments in
optical setups are sensitive to ALPs in the mass range and can
thus complement ALP searches at dipole magnets.Comment: 25 pages, 2 figure
Neurodegeneration and Epilepsy in a Zebrafish Model of CLN3 Disease (Batten Disease)
The neuronal ceroid lipofuscinoses are a group of lysosomal storage disorders that comprise the most common, genetically heterogeneous, fatal neurodegenerative disorders of children. They are characterised by childhood onset, visual failure, epileptic seizures, psychomotor retardation and dementia. CLN3 disease, also known as Batten disease, is caused by autosomal recessive mutations in the CLN3 gene, 80–85% of which are a ~1 kb deletion. Currently no treatments exist, and after much suffering, the disease inevitably results in premature death. The aim of this study was to generate a zebrafish model of CLN3 disease using antisense morpholino injection, and characterise the pathological and functional consequences of Cln3 deficiency, thereby providing a tool for future drug discovery. The model was shown to faithfully recapitulate the pathological signs of CLN3 disease, including reduced survival, neuronal loss, retinopathy, axonopathy, loss of motor function, lysosomal storage of subunit c of mitochondrial ATP synthase, and epileptic seizures, albeit with an earlier onset and faster progression than the human disease. Our study provides proof of principle that the advantages of the zebrafish over other model systems can be utilised to further our understanding of the pathogenesis of CLN3 disease and accelerate drug discovery
Direct Interband Light Absorption in Strongly Prolated Ellipsoidal Quantum Dots’ Ensemble
Within the framework of adiabatic approximation, the energy levels and direct interband light absorption in a strongly prolated ellipsoidal quantum dot are studied. Analytical expressions for the particle energy spectrum and absorption threshold frequencies in three regimes of quantization are obtained. Selection rules for quantum transitions are revealed. Absorption edge and absorption coefficient for three regimes of size quantization (SQ) are also considered. To facilitate the comparison of obtained results with the probable experimental data, size dispersion distribution of growing quantum dots by the small semiaxe in the regimes of strong and weak SQ by two experimentally realizing distribution functions have been taken into account. Distribution functions of Lifshits–Slezov and Gaussian have been considered
African-Caribbean cancer consortium for the study of viral, genetic and environmental cancer risk factors
This is a short summary of a meeting of the "African-Caribbean Cancer Consortium", jointly organized by the University of Pittsburgh, Department of Epidemiology and the University of Pittsburgh Cancer Institute, held in Montego Bay, Jamaica as a satellite meeting at the Caribbean Health Research Council, 52nd Annual Council and Scientific meeting on May 4, 2007
CKM matrix and CP violation in B-mesons
Planned as a review of CPV in B-mesons which covered recent B-factories
results these lectures appeared to be a bit wider. It is not natural to be
limited by direct CPV and that in mixing in B-mesons and not to speak about the
analogous phenomena in K-mesons since it is very useful and interesting to
study what is common and what is different in these systems and why. CKM matrix
elements are extracted from K and B mixings and decays and the deviation from
unitarity of CKM matrix may become a place in which New Physics will show up.
So we discuss this simple and elegant piece of Standard Model as well.Comment: 51 pages, 10 figures, to be published in the Proceedings of the XXXI
ITEP Winter School, Moscow, Russia, 18-26 February 200