Amplitude analysis of reactions pi(-)p->etapi(-)p and pi(-)p->etapi(0)n on polarized target and the exotic 1-+ meson

Recently several experimental groups analysed data on $\pi^- p \to \eta \pi^- p$ and $\pi^- p \to \eta \pi^0 n$ reactions with exotic $1^{-+}$ $P$-wave and found a conflicting evidence for an exotic meson $I=1 1^{-+} (1405)$. High statistics data on these reactions are presently analysed by BNL E852 Collaboration. All these analyses are based on the crucial assumption that the production amplitudes do not depend on nucleon spin. This assumption is in sharp conflict with the results of measurements of $\pi^- p \to \pi^- \pi^+ n$, $\pi^+ n \to \pi^+ \pi^- p$ and $K^+ n \to K^+ \pi^- p$ on polarized targets at CERN which find a strong dependence of production amplitudes on nucleon spin. To ascertain the existence of exotic meson $1^{-+} (1405)$, it is necessary to perform a model-independent amplitude analysis of reactions $\pi^- p \to \eta \pi^- p$ and $\pi^- p \to \eta\pi^0 n$. We demonstrate that measurements of these reactions on transversely polarized targets enable the required model independent amplitude analysis without the assumption that production amplitudes are independent on nucleon spin. We suggest that high statistics measurements of reactions $\pi^- p \to \eta\pi^- p$ and $\pi^- p \to\eta\pi^0 n$ be made on polarized targets at BNL and at Protvino IHEP, and that model-independent amplitude analyses of this polarized data be performed to advance hadron spectroscopy on the level of spin dependent production amplitudes.Comment: 23 page

Senior Recital:Thomas D. Svec, Trumpet

Kemp Recital Hall Saturday Afternoon April 4, 1998 3:00p.m

Virtua l audiology education tools: A survey of faculty, graduate students, and undergraduate students

Due to global shifts at educational institutions from in-person courses to online formats caused by the COVID-19 pandemic, the current study aimed to estimate whether currently available virtual audiology education tools are helpful for acquiring necessary audiology skills and knowledge from the perspective of both educators and students. Therefore, a remote survey was developed and distributed to faculty and students in undergraduate communication sciences disorders and graduate audiology programs. Although participation was somewhat limited, the trends observed in the survey results suggested that the majority of both educators and students found the subset of virtual tools easy to use, that these tools improved teaching methods and learning outcomes, and that these tools would likely be used again

Enhancement of Electrical Conduction and Phonon Scattering in Ga2O3(ZnO)9-In2O3(ZnO)9 Compounds by Modification of Interfaces at the Nanoscale

The Ga2O3(ZnO)9 and In2O3(ZnO)9 homologous phases have attracted attention as thermoelectric (TE) oxides due to their layered structures. Ga2O3(ZnO)9 exhibits low thermal conductivity, while In2O3(ZnO)9 possesses higher electrical conductivity. The TE properties of the solid solution of Ga2O3(ZnO)9-In2O3(ZnO)9 were explored and correlated with changes in the crystal structure. High-quality (1−x)Ga2O3(ZnO)9-(ZnO)9 (x = 0.0 to 1.0) ceramics were prepared by the solid-state route using B2O3 and Nd2O3 as additives. The crystal structures were analysed by x-ray diffraction, high-resolution transmission electron microscopy and atomic resolution scanning transmission electron microscopy–high-angle annular dark field imaging–energy dispersive x-ray spectroscopy (STEM–HAADF–EDS) techniques. A layered superstructure with compositional modulations was observed in all samples in the (1−x)Ga2O3(ZnO)9-xIn2O3(ZnO)9 system. All the ceramics exhibited nanoscale structural features identified as Ga- and In-rich inversion boundaries (IBs). Substitution of 20 mol.% In (x = 0.2) in the Ga2O3(ZnO)9 compounds generated basal and pyramidal indium IBs typically found in the In2O3(ZnO)m system. The (Ga0.8In0.2)2O3(ZnO)9 compound does not exhibit the structural features of the Cmcm Ga2O3(ZnO)9 compound, which is formed by a stacking of Ga-rich IBs along the pyramidal plane of the wurtzite ZnO, but features that resemble the crystal structure exhibited by the R3¯¯¯m In2O3(ZnO)m with basal and pyramidal indium IBs. The structural changes led to improved TE performance. For example, (Ga0.8In0.2)2O3(ZnO)9 showed a low thermal conductivity of 2 W/m K and a high power factor of 150 μW/m K2 giving a figure of merit (ZT) of 0.07 at 900 K. This is the highest ZT for Ga2O3(ZnO)9-based homologous compounds and is comparable with the highest ZT reported for In2O3(ZnO)9 homologous compounds

Unitarity and Interfering Resonances in pipi Scattering and in Pion Production piN->pipiN

Additivity of Breit-Wigner phases has been proposed to describe interfering resonances in partial waves in $\pi\pi$ scattering. This assumption leads to an expression for partial wave amplitudes that involves products of Breit-Wigner amplitudes. We show that this expression is equivalent to a coherent sum of Breit-Wigner amplitudes with specific complex coefficients which depend on the resonance parameters of all contributing resonances. We use analyticity of $\pi\pi$ partial wave amplitudes to show that they must have the form of a coherent sum of Breit-Wigner amplitudes with complex coefficients and a complex coherent background. The assumption of additivity of Breit-Wigner phases restricts the partial waves to analytical functions with very specific form of residues of Breit-Wigner poles. We argue that the general form provided by the analyticity is more appropriate in fits to data to determine resonance parameters. The partial wave unitarity can be imposed using the modern methods of constrained optimization. We discuss unitarity and the production amplitudes in $\pi N\to\pi\pi N$ and use analyticity in the dipion mass variable to justify the common practice of writing the production amplitudes as a coherent sum of Breit-Wigner amplitudes with free complex coefficients and a complex coherent background in fits to mass spectra with interfering resonances.Comment: 31 page

Senior Recital:Danielle L. Dauw, Trumpet Karen Collier, Piano with guest Thomas D. Svec, Trumpet

Kemp Recital Hall Thursday Evening April 24, 1997 8:30 p.m

Relevance of nucleon spin in amplitude analysis of reactions pi(-)p->pi(0)pi(0)n and pi(-)p->eta eta n

The measurements of reactions $\pi^- p \to \pi^- \pi^+ n$ and $\pi^+ n \to \pi^+ \pi^- p$ on polarized targets at CERN found a strong dependence of pion production amplitudes on nucleon spin. Analyses of recent measurements of $\pi^- p \to \pi^0\pi^0 n$ reaction on unpolarized targets by GAMS Collaboration at 38 GeV/c and BNL E852 Collaboration at 18 GeV/c use the assumption that pion production amplitudes do not depend on nucleon spin, in conflict with the CERN results on polarized targets. We show that measurements of $\pi^- p \to \pi^0\pi^0 n$ and $\pi^- p \to \eta\eta n$ on unpolarized targets can be analysed in a model independent way in terms of 4 partial-wave intensities and 3 independent interference phases in the mass region where $S$- and $D$-wave dominate. We also describe model-independent amplitude analysis of $\pi^- p \to \pi^0\pi^0 n$ reaction measured on polarized target, both in the absence and in the presence of $G$-wave amplitudes. We suggest that high statistics measurements of reactions $\pi^- p \to \pi^0 \pi^0 n$ and $\pi^- p \to \eta\eta n$ be made on polarized targets at Protvino IHEP and at BNL, and that model-independent amplitude analyses of this polarized data be performed to advance hadron spectroscopy on the level of spin dependent production amplitudes.Comment: 54 page

Dynamical Generation of Linear σ\sigma model SU(3) Lagrangian and Meson Nonet Mixing

This paper is the SU(3) extension of the dynamically generated SU(2) linear $\sigma$ model Lagrangian worked out previously using dimensional regularization. After discussing the quark-level Goldberger-Treiman relations for SU(3) and the related gap equations, we dynamically generate the meson cubic and quartic couplings. This also constrains the meson-quark coupling constant to $g=2\pi/\sqrt3$ and determines the SU(3) scalar meson masses in a Nambu-Jona-Lasinio fashion. Finally we dynamically induce the U(3) pseudoscalar and scalar mixing angles in a manner compatible with data.Comment: 19 printed pages, requires plain Tex, now published in IJMPA 13, 657 (1998

ππ\pi\pi scattering S wave from the data on the reaction π−p→π0π0n\pi^-p\to\pi^0\pi^0n

The results of the recent experiments on the reaction $\pi^-p\to\pi^0\pi^0n$ performed at KEK, BNL, IHEP, and CERN are analyzed in detail. For the I=0 $\pi\pi$ S wave phase shift $\delta^0_0$ and inelasticity $\eta^0_0$ a new set of data is obtained. Difficulties emerging when using the physical solutions for the $\pi^0\pi^0$ S and D wave amplitudes extracted with the partial wave analyses are discussed. Attention is drawn to the fact that, for the $\pi^0\pi^0$ invariant mass, m, above 1 GeV, the other solutions, in principle, are found to be more preferred. For clarifying the situation and further studying the $f_0(980)$ resonance thorough experimental investigations of the reaction $\pi^-p\to\pi^0\pi^0n$ in the m region near the $K\bar K$ threshold are required.Comment: 17 pages, 5 figure

Mass and width of sigma(750) scalar meson from measurements of piN->pi(-)pi(+)N on polarized targets

The measurements of reactions $\pi^- p_\uparrow \to \pi^- \pi^+ n$ at 17.2 GeV/c and $\pi^+ n_\uparrow \to \pi^+ \pi^- p$ at 5.98 and 11.85 GeV/c made at CERN with polarized targets provide a model-independent and solution-independent evidence for a narrow scalar state sigma(750). The original chi^2 minimization method and the recent Monte Carlo method for amplitude analysis of data at 17.2 GeV/c are in excellent agreement. Both methods find that the mass distribution of the measured amplitude $|\overline S |^2\Sigma$ with recoil transversity ``up'' resonates near 750 MeV while the amplitude $|S|^2\Sigma$ with recoil transversity ``down'' is large and nonresonating. The amplitude $|S|^2\Sigma$ contributes as a strong background to S-wave intensity I_S = (|S|^2 + |\overline S |^2)\Sigma$and distorts the determinations of$\sigma$resonance parameters from$I_S$. To avoid this problem we perform a series of Breit-Wigner fits directly to the measured distribution$|\overline S |^2\Sigma$. The inclusion of various backgrounds causes the width of sigma(750) to become very narrow. Our best fit with$t$-averaged coherent background yields$m_\sigma = 753 \pm 19$MeV and$\Gamma_\sigma = 108 \pm 53$MeV. These values are in excellent agreement with Ellis-Lanik theorem for the width of scalar gluonium. The gluonium interpretation of$\sigma(750)$is also supported by the absence of$\sigma(750)$in reactions$\gamma\gamma \to \pi\pi$. We also show how data on polarized target invalidate essential assumptions of past determinations of$\pi\pi$ phase shifts .Comment: 77 page