795 research outputs found
Mass and width of sigma(750) scalar meson from measurements of pi(-)p->pi(-)pi(+)n on polarized target
Model independent amplitude analyses of
on polarized target at 17.2 GeV/c reveal resonant structure of S-wave
transversity amplitudes and near 750 MeV.
Simultaneous fit to and with a single
pole yields MeV and MeV.
Simultaneous fit with two common poles yields a lower .
Their resonance parameters are MeV, MeV and MeV,
MeV.Comment: 4 pages, 3 figure
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
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
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
Visitors' preferences of renewable energy options in 'green' hotels.
Tourism belongs to the industries with significant energy consumption. Visitors as well as hotel managers have, however, a positive attitude towards the responsible use of energy resources. The level of research on visitors’ preferences of using different types of renewable energy is low, unlike findings on factual characteristics of conventional and renewable energies. That is why our aim was to assess visitors’ preferences of environmentally friendly energy sources in hotels. Preferences of six types of renewable energy - “green” tariff energy, solar panels on the rooftops, solar panels on the ground, heat pumps, AD, wind turbine, were measured at four tourist destinations in the Czech Republic. The positive attitude of tourists towards the selected types of energy sources was confirmed. The highest preferences were found for solar panels installed on the rooftops. A typology of preferences was revealed by cluster analysis and differences between clusters were tested for independent variables. Clusters of visitors with a high and low interest in any type of renewable energy were identified as well as a cluster of visitors with interest in all types apart from solar panels installed on the ground - the visitor’s origin was found as the main differentiation factor
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