Related papers: Extracting resonance poles from numerical scatteri…
In a finite volume, resonances and multi-hadron states are identified by discrete energy levels. When comparing the results of lattice QCD calculations to scattering experiments, it is important to have a way of associating the energy…
We study partial fraction decompositions (PFDs) in several variables using tools from commutative algebra. We give criteria for when a rational function with poles on a hyperplane arrangement has a desirable PFD. Our criteria are obtained…
Making use of the analytical properties of the $S$-matrix and a theorem of Mittag-Leffler, model independent non-relativistic expressions for cross sections in single channel elastic scattering, scattering phase shifts and survival…
We describe upgrades to a numerical code which computes synchrotron and inverse-Compton emission from relativistic plasma including full polarization. The introduced upgrades concern scattering kernel which is now capable of scattering the…
Resonances, or scattering poles, are complex numbers which mathematically describe meta-stable states: the real part of a resonance gives the rest energy, and its imaginary part, the rate of decay of a meta-stable state. This description…
Structures in the invariant mass distribution are often linked to unstable intermediate states or resonances. In experiments, many signals are detected which have broad, overlapping or intricate profiles, which makes their characterization…
The article contains new results for spin-3/2 and -1/2 resonances. It specializes to the second resonance region, which includes the $P_{11}(1440)$, $D_{13}(1520)$ and $S_{11}(1535)$ resonances. New data on electroproduction enable us to…
Unconstrained partial-wave amplitudes obtained at discrete energies from fits to complete sets of eight independent observables which are required to uniquely reconstruct reaction amplitudes do not vary smoothly with energy, and are in…
In hadron resonant scattering, there are four fundamental resonant parameters: real and imaginary part of the pole position, and the magnitude and the phase of the residue. Out of the four, the last one is the least understood. The search…
The explicit formulae for radiative correction (RC) calculation for elastic $ep$-scattering is presented. Two typical measurements of polarization observables such as beam-target asymmetry or recoil proton polarization, are considered.…
We study the low-energy 3/2- and 1/2- states of He-5 and Li-5 in a microscopic cluster model. The scattering phase shifts of Bond (alpha+n) and of Schwandt (alpha+p), respectively, are reproduced well. We determine the resonance parameters…
Reconstructing unstable heavy particles requires sophisticated techniques to sift through the large number of possible permutations for assignment of detector objects to the underlying partons. Anapproach based on a generalized attention…
We explain how an analytic continuation we have developed recently is applied to determine the residues of the nucleon resonance poles within a dynamical coupled-channel model of meson-baron reactions. A procedure for evaluating the…
A novel method for extracting multipole amplitudes in the nucleon resonance region from electroproduction data is presented. The method is based on statistical concepts and it relies heavily on Monte Carlo and simulation techniques; it…
The scattering phase shift encodes a good amount of physical information which can be used to study resonances from scattering data. Among others, it can be used to calculate the continuum density of states and the collision time in a…
A scattering method is used to calculate the surface band structure of Al(111) from 8.6 eV below the Fermi level to 9 eV above it. This method has rarely been implemented previously. The complete complex bulk and surface band structure is…
We extend the 1/N_c expansion meson-baryon scattering formalism to cases in which the final state contains more than two particles. We first show that the leading-order large N_c processes proceed through resonant intermediate states (e.g.,…
The elastic and radiative pion(+)-proton scattering are studied in the framework of an effective Lagrangian model for the Delta^{++} resonance and its interactions. The finite width effects of this spin-3/2 resonance are introduced in the…
An important question about resonance extraction is how much resonance poles and residues extracted from data depend on a model used for the extraction, and on the precision of data. We address this question with the dynamical…
We present a novel approach for the integration of scattering cross sections and the generation of partonic event samples in high-energy physics. We propose an importance sampling technique capable of overcoming typical deficiencies of…