Associated strangeness production in the pp to pK^+K^-p and pp to pK^+ pi^0 Sigma^0 reactions

The total and differential cross sections for associated strangeness production in the $pp \to pK^+K^-p$ and $pp \to pK^+\pi^0\Sigma^0$ reactions have been studied in a unified approach using an effective Lagrangian model. It is assumed that both the $K^-p$ and $\pi^0\Sigma^0$ final states originate from the decay of the $\Lambda(1405)$ resonance which was formed in the production chain $pp\to p(N^*(1535)\to K^+\Lambda(1405))$. The available experimental data are well reproduced, especially the ratio of the two total cross sections, which is much less sensitive to the particular model of the entrance channel. The significant coupling of the $N^*(1535)$ resonance to $\Lambda(1405) K$ is further evidence for large $s \bar{s}$ components in the quark wave function of the $N^*(1535)$ resonance.Comment: Published in Phys. Rev.

Feature Tracking Cardiac Magnetic Resonance via Deep Learning and Spline Optimization

Feature tracking Cardiac Magnetic Resonance (CMR) has recently emerged as an area of interest for quantification of regional cardiac function from balanced, steady state free precession (SSFP) cine sequences. However, currently available techniques lack full automation, limiting reproducibility. We propose a fully automated technique whereby a CMR image sequence is first segmented with a deep, fully convolutional neural network (CNN) architecture, and quadratic basis splines are fitted simultaneously across all cardiac frames using least squares optimization. Experiments are performed using data from 42 patients with hypertrophic cardiomyopathy (HCM) and 21 healthy control subjects. In terms of segmentation, we compared state-of-the-art CNN frameworks, U-Net and dilated convolution architectures, with and without temporal context, using cross validation with three folds. Performance relative to expert manual segmentation was similar across all networks: pixel accuracy was ~97%, intersection-over-union (IoU) across all classes was ~87%, and IoU across foreground classes only was ~85%. Endocardial left ventricular circumferential strain calculated from the proposed pipeline was significantly different in control and disease subjects (-25.3% vs -29.1%, p = 0.006), in agreement with the current clinical literature.Comment: Accepted to Functional Imaging and Modeling of the Heart (FIMH) 201

A statistical model approximation for perovskite solid-solutions: a Raman study of lead-zirconate-titanate single crystal

Lead titanate (PbTiO3) is a classical example of a ferroelectric perovskite oxide illustrating a displacive phase transition accompanied by a softening of a symmetry-breaking mode. The underlying assumption justifying the soft-mode theory is that the crystal is macroscopically sufficiently uniform so that a meaningful free energy function can be formed. In contrast to PbTiO3, experimental studies show that the phase transition behaviour of lead-zirconate-titanate solid solution (PZT) is far more subtle. Most of the studies on the PZT system have been dedicated to ceramic or powder samples, in which case an unambiguous soft-mode study is not possible, as modes with different symmetries appear together. Our Raman scattering study on titanium-rich PZT single crystal shows that the phase transitions in PZT cannot be described by a simple soft-mode theory. In strong contrast to PbTiO3, splitting of transverse E-symmetry modes reveals that there are different locally-ordered regions. The role of crystal defects, random distribution of Ti and Zr at the B-cation site and Pb ions shifted away from their ideal positions, dictates the phase transition mechanism. A statistical model explaining the observed peak splitting and phase transformation to a complex state with spatially varying local order in the vicinity of the morphotropic phase boundary is given.Comment: Article contains four black-and-white figures, one colour figure and one Table. Symmetry analysis and details of the model are given in Appendices I and II, respectivel

Intermediate-statistics quantum bracket, coherent state, oscillator, and representation of angular momentum (su(2)) algebra

In this paper, we first discuss the general properties of an intermediate-statistics quantum bracket, $[ u,v]_{n}=uv-e^{i2\pi /(n+1)}vu$, which corresponds to intermediate statistics in which the maximum occupation number of one quantum state is an arbitrary integer, $n$. A further study of the operator realization of intermediate statistics is given. We construct the intermediate-statistics coherent state. An intermediate-statistics oscillator is constructed, which returns to bosonic and fermionic oscillators respectively when $n\to \infty$ and $n=1$. The energy spectrum of such an intermediate-statistics oscillator is calculated. Finally, we discuss the intermediate-statistics representation of angular momentum ($su(2)$) algebra. Moreover, a further study of the operator realization of intermediate statistics is given in the Appendix.Comment: 12 pages, no figures. Revte

A Simple Three-Parameter Model Potential For Diatomic Systems: From Weakly and Strongly Bound Molecules to Metastable Molecular Ions

Based on a simplest molecular orbital theory of H$_{2}^{+}$, a three-parameter model potential function is proposed to describe ground-state diatomic systems with closed-shell and/or S-type valence-shell constituents over a significantly wide range of internuclear distances. More than 200 weakly and strongly bound diatomics have been studied, including neutral and singly-charged diatomics (e.g., H$_{2}$, Li$_{2}$, LiH, Cd$_{2}$, Na$_{2}^{+}$, and RbH$^{-}$), long-range bound diatomics (e.g., NaAr, CdNe, He$_{2}$, CaHe, SrHe, and BaHe), metastable molecular dications (e.g., BeH$^{++}$, AlH$^{++}$, Mg$_{2}^{++}$, and LiBa$^{++}$), and molecular trications (e.g., YHe$^{+++}$ and ScHe$^{+++}$).Comment: 5 pages, 4 figures, accepted by Physical Review Letter