Hyperfine mixing in electromagnetic decay of doubly heavy bcbc baryons

We investigate the role of hyperfine mixing in the electromagnetic decay of ground state doubly heavy $bc$ baryons. As in the case of a previous calculation on $b\to c$ semileptonic decays of doubly heavy baryons, we find large corrections to the electromagnetic decay widths due to this mixing. Contrary to the weak case just mentioned, we find here that one can not use electromagnetic width relations obtained in the infinite heavy quark mass limit to experimentally extract information on the admixtures in a model independent way.Comment: 9 Latex pages, 4 tables. A new reference added. A few misprints correcte

Using genetic monitoring to inform best practice in a captive breeding programme:Inbreeding and potential genetic rescue in the freshwater pearl mussel Margaritifera margaritifera

Freshwater pearl mussel (Margaritifera margaritifera) populations are declining in Northern Ireland to the extent that a captive breeding programme was established on the Upper Ballinderry river in 1998. Previous genetic analysis of the hatchery broodstock and their first cohort of offspring showed significant levels of inbreeding (FIS = 0.166). The broodstock, which currently numbers ca. 90 individuals, was supplemented with new individual mussels, whilst in 2013, a previously unknown population was discovered on the Lower Ballinderry river. The aim of the present study was to determine whether the rotation of the broodstock has led to a decrease in the levels of inbreeding in the second cohort of juveniles, and to determine whether the new population found in the Lower Ballinderry was genetically distinct from the captive bred population and populations from the Upper Ballinderry, which represent the source of the hatchery broodstock. Genotyping using eight microsatellite markers indicated that levels of inbreeding in the second cohort of captive-bred mussels were high, (FIS = 0.629), and were comparable to those sampled from the original cohort and the hatchery broodstock (FIS = 0.527 and 0.636 respectively). Bayesian analysis of population structure indicated that the newly discovered Lower Ballinderry population was genetically distinct from the broodstock and its source populations on the Upper Ballinderry. The observed differentiation was primarily due to differences in allele frequencies, and was most likely a result of genetic drift. The occurrence of ten alleles, albeit at low frequency, in the Lower Ballinderry population, including four private alleles, suggests that this new population could be incorporated into the broodstock with the aim of decreasing levels of inbreeding in the future.<br/

NLSEmagic: Nonlinear Schr\"odinger Equation Multidimensional Matlab-based GPU-accelerated Integrators using Compact High-order Schemes

We present a simple to use, yet powerful code package called NLSEmagic to numerically integrate the nonlinear Schr\"odinger equation in one, two, and three dimensions. NLSEmagic is a high-order finite-difference code package which utilizes graphic processing unit (GPU) parallel architectures. The codes running on the GPU are many times faster than their serial counterparts, and are much cheaper to run than on standard parallel clusters. The codes are developed with usability and portability in mind, and therefore are written to interface with MATLAB utilizing custom GPU-enabled C codes with the MEX-compiler interface. The packages are freely distributed, including user manuals and set-up files.Comment: 37 pages, 13 figure

Decay constants of the pseudoscalar mesons in the framework of the coupled Schwinger-Dyson equation and Bethe-Salpeter equation

In this article, we investigate the structures of the pseudoscalar mesons ($\pi$, $K$, $D$, $D_s$, $B$ and $B_s$) in the framework of the coupled rainbow Schwinger-Dyson equation and ladder Bethe-Salpeter equation with the confining effective potential (infrared modified flat bottom potential). The Schwinger-Dyson functions for the $u$, $d$ and $s$ quarks are greatly renormalized at small momentum region and the curves are steep at about $q^2=1GeV^2$ which indicates an explicitly dynamical symmetry breaking. The Euclidean time fourier transformed quark propagators have no mass poles in the time-like region which naturally implements confinement. As for the $c$ and $b$ quarks, the current masses are very large, the renormalization are more tender, however, mass poles in the time-like region are also absent. The Bethe-Salpeter wavefunctions for those mesons have the same type (Gaussian type) momentum dependence and center around small momentum which indicate that the bound states exist in the infrared region. The decay constants for those pseudoscalar mesons are compatible with the values of experimental extractions and theoretical calculations, such as lattice simulations and QCD sum rules.Comment: 10 pages, 4 figures, Revised Versio

Reanalysis of the heavy baryon states Ωb\Omega_b, Ωc\Omega_c, Ξb′\Xi'_b, Ξc′\Xi'_c, Σb\Sigma_b and Σc\Sigma_c with QCD sum rules

In this article, we re-study the heavy baryon states $\Omega_b$, $\Omega_c$, $\Xi'_b$, $\Xi'_c$, $\Sigma_b$ and $\Sigma_c$ with the QCD sum rules, after subtracting the contributions from the corresponding negative parity heavy baryon states, the predicted masses are in good agreement with the experimental data.Comment: 12 pages, 14 figures, revised versio

Phases in the MSSM, Electric Dipole Moments and Cosmological Dark Matter

We consider the effect of CP violating phases in the MSSM on the relic density of the lightest supersymmetric particle (LSP). In particular, we find that the upper limits on the LSP mass are relaxed when phases in the MSSM are allowed to take non-zero values when the LSP is predominantly a gaugino (bino). Previous limits of \mb \la 250 GeV for $\Omega h^2 < 0.25$ can be relaxed to \mb \la 650 GeV. We also consider the additional constraints imposed by the neutron and electron electric dipole moments induced by these phases. Though there is some restriction on the phases, the bino mass may still be as large as $\sim$ 350 GeV and certain phases can be arbitrarily large.Comment: 10 pages in LaTeX, with 4 Postscript figures (included