scholarly journals An Analytic Distorted Wave Approximation for Electropion and Photopion Production on 12C near Threshold

1986 ◽  
Vol 39 (2) ◽  
pp. 203 ◽  
Author(s):  
F Di Marzio ◽  
K Amos
Keyword(s):  
Cross Sections ◽  
Production Cross ◽  
Distorted Wave ◽  
Pion Scattering ◽  
Wave Approximation ◽  
Microscopic Models ◽  
Transition Densities ◽  
Analyse Data ◽  
Near Threshold

An analytic distorted wave approximation (ADWA) that can be used to analyse photopion and electropion production cross sections is developed. An application is made to analyse data from 12C near threshold once the approximation scheme is established as a realistic replacement for the more usual, distorted wavefunctions given by the optical model for low energy pion scattering. The pion production data analyses made using a generalized Helm model for the transition densities clearly demonstrates the significant role of distortion effects and that the ADW A is a good and simple representation of these effects. Repeating the analyses using microscopic models of nuclear structure indicates inadequacies in those structure specifications.

A Comparison of Spectroscopic Models of Low Excitation 2+ States in 24Mg and 28Si from Inelastic Proton Scattering

1980 ◽  
Vol 33 (3) ◽  
pp. 495 ◽  
Author(s):  
K Amos ◽  
P Nesci ◽  
I Morrison
Keyword(s):  
Inelastic Scattering ◽  
Shell Model ◽  
Proton Scattering ◽  
Distorted Wave ◽  
Potential Models ◽  
Wave Approximation ◽  
Transition Mechanism ◽  
Transition Densities ◽  
Inelastic Proton Scattering ◽  
Mev Protons

Distorted wave approximation analyses of the inelastic scattering of 49�5 MeV protons from 24Mg and 28Si are used to compare 2 + transition densities that were obtained from a standard shell model, deformed potential models and an SU(3) model of the low excitation spectroscopy of these nuclei. Analysing power predictions do not reproduce the data adequately, and the discrepancies indicate a deficiency in the prescription for the transition mechanism.

scholarly journals Ground State Positronium Formation Cross Sections for Scattering of Positrons from Li

1991 ◽  
Vol 44 (5) ◽  
pp. 515 ◽  
Author(s):  
KK Mukherjee ◽  
N Ranjit Singh ◽  
Keka Basu Choudhury ◽  
PS Mazumdar ◽  
S Brajamani
Keyword(s):  
Energy Range ◽  
Cross Sections ◽  
Ground State ◽  
Positronium Formation ◽  
Distorted Wave ◽  
Total Cross Sections ◽  
Wave Approximation ◽  
Theoretical Predictions

Total cross sections for positronium formation in e+-Li scattering have been studied in the framework of the distorted wave approximation in the energy range 1-50 eV by taking consistent account of the effect of the target distortion. The results are compared with existing theoretical predictions.

scholarly journals Cosmic-ray antiprotons in the AMS-02 era: A sensitive probe of dark matter

2020 ◽  
pp. 2130003
Author(s):  
Jan Heisig
Keyword(s):  
Dark Matter ◽  
Cross Sections ◽  
Production Cross ◽  
Cosmic Ray ◽  
Systematic Errors ◽  
Primary Component ◽  
Special Role ◽  
Correlated Errors ◽  
Precise Data

Cosmic-ray antiprotons are a powerful tool for astroparticle physics. While the bulk of measured antiprotons is consistent with a secondary origin, the precise data of the AMS-02 experiment provides us with encouraging prospects to search for a subdominant primary component, e.g. from dark matter. In this brief review, we discuss recent limits on heavy dark matter as well as a tentative signal from annihilation of dark matter with a mass [Formula: see text][Formula: see text]100 GeV. We emphasize the special role of systematic errors that can affect the signal. In particular, we discuss recent progress in the modeling of secondary production cross-sections and correlated errors in the AMS-02 data, the dominant ones originating from uncertainties in the cross-sections for cosmic-ray absorption in the detector.

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