Charmed Baryon Weak Decays with SU(3) Flavor Symmetry

We study the semileptonic and non-leptonic charmed baryon decays with $SU(3)$ flavor symmetry, where the charmed baryons can be ${\bf B}_{c}=(\Xi_c^0,\Xi_c^+,\Lambda_c^+)$, ${\bf B}'_{c}=(\Sigma_c^{(++,+,0)},\Xi_{c}^{\prime(+,0)},\Omega_c^0)$, ${\bf B}_{cc}=(\Xi_{cc}^{++},\Xi_{cc}^+,\Omega_{cc}^+)$, or ${\bf B}_{ccc}=\Omega^{++}_{ccc}$. With ${\bf B}_n^{(\prime)}$ denoted as the baryon octet (decuplet), we find that the ${\bf B}_{c}\to {\bf B}'_n\ell^+\nu_\ell$ decays are forbidden, while the $\Omega_c^0\to \Omega^-\ell^+\nu_\ell$, $\Omega_{cc}^+\to\Omega_c^0\ell^+\nu_\ell$, and $\Omega_{ccc}^{++}\to \Omega_{cc}^+\ell^+\nu_\ell$ decays are the only existing Cabibbo-allowed modes for ${\bf B}'_{c}\to {\bf B}'_n\ell^+\nu_\ell$, ${\bf B}_{cc}\to {\bf B}'_c\ell^+\nu_\ell$, and ${\bf B}_{ccc}\to {\bf B}_{cc}^{(\prime)}\ell^+\nu_\ell$, respectively. We predict the rarely studied ${\bf B}_{c}\to {\bf B}_n^{(\prime)}M$ decays, such as ${\cal B}(\Xi_c^0\to\Lambda^0\bar K^0,\,\Xi_c^+\to\Xi^0\pi^+)=(8.3\pm 0.9,8.0\pm 4.1)\times 10^{-3}$ and ${\cal B}(\Lambda_c^+\to \Delta^{++}\pi^-,\,\Xi_c^0\to\Omega^- K^+)=(5.5\pm 1.3,4.8\pm 0.5)\times 10^{-3}$. For the observation, the doubly and triply charmed baryon decays of $\Omega_{cc}^{+}\to \Xi_c^+\bar K^0$, $\Xi_{cc}^{++}\to (\Xi_c^+\pi^+$, $\Sigma_c^{++}\bar K^0)$, and $\Omega_{ccc}^{++}\to (\Xi_{cc}^{++}\bar K^0,\Omega_{cc}^+\pi^+,\Xi_c^+ D^+)$ are the favored Cabibbo-allowed decays, which are accessible to the BESIII and LHCb experiments.Comment: 29 pages, no figure, a typo in the table correcte

A high flux source of cold strontium atoms

We describe an experimental apparatus capable of achieving a high loading rate of strontium atoms in a magneto-optical trap operating in a high vacuum environment. A key innovation of this setup is a two dimensional magneto-optical trap deflector located after a Zeeman slower. We find a loading rate of 6x10^9/s whereas the lifetime of the magnetically trapped atoms in the 3P2 state is 54s.Comment: 12 pages, 16 figure

Leveraging generative adversarial networks to create realistic scanning transmission electron microscopy images

The rise of automation and machine learning (ML) in electron microscopy has the potential to revolutionize materials research through autonomous data collection and processing. A significant challenge lies in developing ML models that rapidly generalize to large data sets under varying experimental conditions. We address this by employing a cycle generative adversarial network (CycleGAN) with a reciprocal space discriminator, which augments simulated data with realistic spatial frequency information. This allows the CycleGAN to generate images nearly indistinguishable from real data and provide labels for ML applications. We showcase our approach by training a fully convolutional network (FCN) to identify single atom defects in a 4.5 million atom data set, collected using automated acquisition in an aberration-corrected scanning transmission electron microscope (STEM). Our method produces adaptable FCNs that can adjust to dynamically changing experimental variables with minimal intervention, marking a crucial step towards fully autonomous harnessing of microscopy big data.Comment: 25 pages, 6 figures, 2 table

Modelling growth of swietenia macrophylla (mahogany) plantation in Gum-Gum Forest Reserve, Sabah.

Growth models can contribute to the forest management decision making process by providing stand development forecasts. Mahogany plantation in Gum-Gum Forest Reserve Sabah was planted in 1968 with spacing 2.74×2.74 m within an area of 0.52 hectare. Diameter at breast height (dbh) and tree height data were collected from year 1969 to 2006. This study aimed to determine the efficient regression equations for growth prediction of the mahogany plantation. Regression models were developed by search from literature as a basis references. Four diameter prediction models and six height prediction models were developed. Proc Reg in SAS was used to evaluate the regression equations. Performance of the model was measured by using root mean square error (RMSE), bias and coefficient of determination (R2). The chosen diameter prediction model is lnH=3.07-10.42D-1+0.1lnA with RMSE (0.31), bias (1.76) and R2 (0.68). The recommended prediction model slightly underestimated the actual diameter. The chosen height prediction model is lnD=354-3.98A-1 with RMSE (0.11), bias (0.01) and R2 (0.91). This recommended height prediction model gives very close height estimate to the actual height

Probing the superconducting gap symmetry of PrRu4_{4}Sb12_{12}: A comparison with PrOs4_{4}Sb12_{12}

We report measurements of the magnetic penetration depth $\lambda$ in single crystals of PrRu$_{4}$Sb$_{12}$ down to 0.1 K. Both $\lambda$ and superfluid density $\rho_{s}$ exhibit an exponential behavior for $T$ $<$ 0.5$T_{c}$, with parameters $\Delta$(0)/\textit{k}$_{B}$\textit{T}$_{c}$ = 1.9 and $\lambda(0)$ = 2900 \AA. The value of $\Delta$(0) is consistent with the specific-heat jump value of $\Delta C/\gamma T_{c}$ = 1.87 measured elsewhere, while the value of $\lambda(0)$ is consistent with the measured value of the electronic heat-capacity coefficient $\gamma$. Our data are consistent with PrRu$_{4}$Sb$_{12}$ being a moderate-coupling, fully-gapped superconductor. We suggest experiments to study how the nature of the superconducting state evolves with increasing Ru substitution for Os

A personal identification biometric system based on back-of-hand vein patterns

This report describes research on the use of back-of-hand vein patterns as a means of uniquely identifying people. In particular it describes a prototype biometric system developed by the Australian Institute of Security and Applied Technology (AISAT). This system comprises an infrared cold source, a monochrome CCD camera, a monochrome frame-grabber, a personal computer, and custom image acquisition, processing, registration, and matching software. The image processing algorithms are based on Mathematical Morphology. Registration is performed using rotation and translation with respect to the centroid of the two-dimensional domain of a hand. Vein patterns are stored as medial axis representations. Matching involves comparing a given medial axis pattern against a library of patterns using constrained sequential correlation. The matching is two-fold: a newly acquired signature is matched against a dilated library signature, and then the library signature is matched against the dilated acquired signature; this is necessary because of the positional noise exhibited by the back-of-hand veins. The results of a cross-matching experiment for a sample of 20 adults and more than 100 hand images is detailed. In addition preliminary estimates of the false acceptance rate (FAR) and false rejection rate (FRR) for the prototype system are given. Fuzzy relaxation on an association graph is discussed as an alternative to sequential correlation for the matching of vein signatures. An example is provided (including a C program) illustrating the matching process for a pair of signatures obtained from the same hand. The example demonstrates the ability of the fuzzy relaxation method to deal with segmentation errors

SU(3) symmetry breaking in charmed baryon decays

We explore the breaking effects of the $SU(3)$ flavor symmetry in the singly Cabibbo-suppressed anti-triplet charmed baryon decays of ${\bf B}_c\to {\bf B}_n M$, with ${\bf B}_c=(\Xi_c^0,\Xi_c^+,\Lambda_c^+)$ and ${\bf B}_n(M)$ the baryon (pseudo-scalar) octets. We find that these breaking effects can be used to account for the experimental data on the decay branching ratios of ${\cal B}(\Lambda_c^+\to \Sigma^{0} K^{+},\Lambda^{0} K^{+})$ and $R'_{K/\pi}$=${\cal B}(\Xi^0_c \to \Xi^- K^+)$/${\cal B}(\Xi^0_c \to \Xi^- \pi^+)$. In addition, we obtain that ${\cal B}(\Xi_{c}^{0} \to \Xi^{-} K^{+},\Sigma^{-} \pi^{+})=(4.6 \pm 1.7,12.8 \pm 3.1)\times 10^{-4}$, ${\cal B}(\Xi_c^0\to pK^-,\Sigma^+\pi^-)=(3.0 \pm 1.0, 5.2 \pm 1.6)\times 10^{-4}$ and ${\cal B}(\Xi_c^+\to \Sigma^{0(+)} \pi^{+(0)})=(10.3 \pm 1.7)\times 10^{-4}$, which all receive significant contributions from the breaking effects, and can be tested by the BESIII and LHCb experiments.Comment: 12 pages, no figure, revised version accepted by EPJ

Composite-fermion crystallites in quantum dots

The correlations in the ground state of interacting electrons in a two-dimensional quantum dot in a high magnetic field are known to undergo a qualitative change from liquid-like to crystal-like as the total angular momentum becomes large. We show that the composite-fermion theory provides an excellent account of the states in both regimes. The quantum mechanical formation of composite fermions with a large number of attached vortices automatically generates omposite fermion crystallites in finite quantum dots.Comment: 5 pages, 3 figure