577 research outputs found
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 and reactions with exotic -wave and
found a conflicting evidence for an exotic meson . 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 ,
and on polarized targets at
CERN which find a strong dependence of production amplitudes on nucleon spin.
To ascertain the existence of exotic meson , it is necessary to
perform a model-independent amplitude analysis of reactions and . 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 and 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 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
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 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 and on polarized targets at CERN found a strong dependence of pion
production amplitudes on nucleon spin. Analyses of recent measurements of
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 and 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 -
and -wave dominate. We also describe model-independent amplitude analysis of
reaction measured on polarized target, both in the
absence and in the presence of -wave amplitudes. We suggest that high
statistics measurements of reactions and 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
scattering S wave from the data on the reaction
The results of the recent experiments on the reaction
performed at KEK, BNL, IHEP, and CERN are analyzed in detail. For the I=0
S wave phase shift and inelasticity a new set
of data is obtained. Difficulties emerging when using the physical solutions
for the S and D wave amplitudes extracted with the partial wave
analyses are discussed. Attention is drawn to the fact that, for the
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 resonance thorough experimental investigations of the
reaction in the m region near the threshold
are required.Comment: 17 pages, 5 figure
Dynamical Generation of Linear model SU(3) Lagrangian and Meson Nonet Mixing
This paper is the SU(3) extension of the dynamically generated SU(2) linear
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 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
Mass and width of sigma(750) scalar meson from measurements of piN->pi(-)pi(+)N on polarized targets
The measurements of reactions at 17.2
GeV/c and 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 with recoil transversity ``up'' resonates near 750 MeV while the
amplitude with recoil transversity ``down'' is large and
nonresonating. The amplitude contributes as a strong background
to S-wave intensity I_S = (|S|^2 + |\overline S |^2)\Sigma\sigmaI_S|\overline S |^2\Sigmatm_\sigma = 753 \pm 19\Gamma_\sigma = 108 \pm 53\sigma(750)\sigma(750)\gamma\gamma \to \pi\pi\pi\pi$ phase shifts .Comment: 77 page
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