Testing Higgs boson scenarios in the phenomenological NMSSM

There could be another scalar in nature quasi-degenerate with the observed one (h125). This is possible in models such as the Next-to-Minimal Supersymmetric Standard Model (NMSSM). The scenario(s) with a single Higgs boson can be compared to that with multiple ones, all near 125 GeV. In order to assess the extent to which the current set of collider, cold dark matter relic density and direct detection limits are capable of discriminating these scenarios, we perform, for the first-time, global fits of a weak-scale phenomenological NMSSM with 26 free parameters using the nested sampling implementation in PolyChord, a next-generation tool for Bayesian inference. The analyses indicate that the data used shows a moderate tendency for supporting the scenario with an additional scalar much lighter than h125 with mass distribution centred below the W-boson mass. More stringent constraints are, however, needed for decisive inference regarding an additional Higgs boson with mass much less than or near 125 GeV.Comment: v3: major revisions, to appear in EPJ

Light and compressed gluinos at the LHC via string theory

In this article, we show that making global fits of string theory model parameters to data is an interesting mechanism for probing, mapping and forecasting connections of the theory to real world physics. We considered a large volume scenario (LVS) with D3-branes matter fields and supersymmetry breaking. A global fit of the parameters to low energy data shows that the set of LVS models are associated with light gluinos which are quasi-degenerate with the neutralinos and charginos they can promptly decay into and thus possibly hidden to current LHC gluino search strategies.Comment: v2: minor edits, additional references, accepted for publication in the European Physical Journal

Collective spontaneous emission from a system of quantum dots

We study the spontaneous emission from a regular lateral array or a randomly distributed ensemble of quantum dots under strong excitation (full inversion) conditions. We focus on the similarities and differences between the cases of random and regular arrangement of the dots and show that there is very little difference between the evolution of luminescence in these two cases, both for identical dots and for a realistically inhomogeneously broadened ensemble. This means that the enhanced emission or superradiance effect is not due to accidental clustering of pairs of dots. Moreover, we point out that observation of an enhanced emission under weak excitation does not prove that true superradiance will develop in a fully inverted system.Comment: 4 pages, 4 figures, conference "Jaszowiec" 201

Collective spontaneous emission from pairs of quantum dots: long-range vs. short-range couplings

We study the spontaneous emission from a coherently delocalized exciton state in a double quantum dot as a function of the distance between the dots, focusing on the similarities and differences between the cases of radiative (long-range, dipole) and tunnel coupling between the excitons in the dots. We show that there may be no qualitative difference between the collective emission induced by these two coupling types in spite of their essentially different physical properties.Comment: 3 pages, 2 figures. Conference "Jaszowiec 2011

Superradiance and enhanced luminescence from ensembles of a few self-assembled quantum dots

We study the evolution of photoluminescence (PL) from homogeneous and inhomogeneous ensembles of a few coupled QDs. We discuss the relation between signals from a given QD ensemble under strong and weak excitation (full inversion and linear response regimes): A system homogeneous enough to manifest superradiant emission when strongly inverted shows a non-exponential decay of the PL signal under spatially coherent weak excitation. In an inhomogeneous ensemble the PL decay is always nearly exponential with a qualitatively different form of the time dependence in the two excitation regimes and with a higher rate under weak excitation.Comment: 5 pages, 3 figures; moderate changes and extension

Stratigraphy, Lithofacies and Environmental Analysis of the Bahi Formation (Late Cretaceous) in the Northwestern Sirte Basin, Libya

The Bahi Formation forms the diachronous lower part of the Upper Cretaceous succession where it is known only from subsurface data in the western part of the Sirte Basin in north central Libya. It consist of interbedded sandstone, siltstone, conglomerate and shale. Core logs indicate that the formation overlies Palaeozoic sediments and occasionally Precambrian basement rocks with profound unconformity and is overlain by marine Upper Cretaceous sediments. It forms the basal unit of a late Cretaceous transgressive sequence which eventually affected virtually all of the country: the marine invasion was from the north or north-west. The thickness of the formation is variable and largely controlled by contemporaneous faulting. The lower part of the formation consists of fine red, silty sandstone with coarse unit at its base. The upper part is mostly with a coarse to very coarse-grained, cross-bedded sandstone and contains glauconite only in its uppermost part. Petrographically, the formation is classified as a subarkosic quartz arenite in composition with carbonate (dolomite and calcite), anhydrite and clay mineral (illite, kaolinite and chlorite) cements. Zircon, tourmaline and rutile are the most abundant heavy minerals throughout the formation. Geochemical studies of the major and trace elements indicate that K2O, Al2O3 and most of the trace elements are associated with feldspar and/or clay minerals. The relationship between the various trace elements shows that the Bahi sediment was derived largely from pre-existing sedimentary sources. The framework mineralogy and the discriminant function analyses of the major elements suggests that the Bahi Formation was derived from a craton interior and/or a passive continental margin. The mineralogy of the uppermost part indicates shallow marine deposition, probably in an oscillating shoreline situation whereas the sedimentological analyses strongly suggest that the bulk of the formation accumulated in fluvial systems which became established prior to the marine incursion

SOLVENCY OF TAKAFUL FUND: A CASE OF SUBORDINATED QARD

There are two elements important in formulating the solvency requirements of a Takaful undertaking namely the Takaful fund and Qard facility. It has been seen in some regulatory frameworks that the regulator puts a requirement on the Takaful operators to show that they are providing some financial support towards the solvency of the Takaful funds. This paper attempts to explain the measures involve the Takaful operator using their shareholders’ funds to provide financial back\ing to support the solvency of Takaful funds through the practices of Qard facility, injection of assets into the Takaful funds and assignment or allocation of assets in the shareholders in the Takaful funds. The paper will focus on the nature of Qard and its basis in the primary sources of Shariah. Is it acceptable legally to subordinate Qard in the case of deficit, deficiency or drawn down of Takaful fund? Finally, the paper will analyze the legal ruling related to Qard and how it is different to conventional insurance practicesTakaful fund, Qard facility, Takaful participants, Solvency, Subordinated Qard