Search results for "Nucleon"

Coincidence experiments with electrons

1995

Coincidence experiments with electrons provide new information on the structure of nucleons and nuclei. Using new CW accelerators, kinematic regions can be explored with high precision which have not been accessible previously. The equipment and the necessary steps in the analysis of (e,e′p) experiments will be discussed and illustrated with new data taken at the MAMI facility.

Prospects for a DVCS measurement at COMPASS

2010

The high energy polarised muon beam available at CERN with the option of using positive or negative muons with opposite polarisation gives COMPASS an excellent possibility to study generalised parton distributions via deeply virtual Compton scattering. In a first step we propose to use an unpolarised proton target to study the slope of the t dependence of the differential cross section as a function of xB j to observe a possible shrinkage of the nucleon with increasing xB j. Furthermore, the beam charge and spin difference will be measured over a wide kinematical range to determine the Compton form factor related to the GPD H. As a second step we consider to use a transversely polarised pro…

Electron Scattering Experiments on Light Nuclei

2020

In this contribution we discuss double-polarised quasi-elastic electron scattering from \({}^{3}\mathrm {He}\) and \({}^{12}\mathrm {C}\). For these nuclei precise data from recent experiments at Jefferson Lab and Mainz have become available, accompanied by a very strong theoretical effort dedicated to understanding these nuclei. The double polarisation experiments presented here offer insight into some of the details of the nuclear structure that could not be accessed by traditional cross-section measurements. The new experimental results show only rough agreement with the calculations and indicate that we do not yet fully understand the structure of these nuclei and nucleon dynamics insid…

Electro-excitation of nucleon resonances and meson production

2005

Contributions to the electromagnetic form factors of the deuteron from isobar configurations

1974

A nonrelativistic calculation of the elastic electron deuteron scattering has been performed in which the effects arising from nucleon polarization have been systematically investigated. These effects have been taken into account by admixing isobar configurations into the deuteron wave function. Explicit expressions for the various contributions to the respective deuteron form factors have been given. At higher momentum transfers inclusion of the isobar configurations leads to a substantial increase in the form factors which qualitatively appears to account for at least some of the discrepancies between theory and experiment.

Accurate Q value for the 74Se double-electron-capture decay

2010

Abstract The Q value of the neutrinoless double-electron-capture ( 0 ν ECEC ) decay of 74Se was measured by using the JYFLTRAP Penning trap. The determined value is 1209.169(49) keV, which practically excludes the possibility of a complete energy degeneracy with the second 2 + state (1204.205(7) keV) of 74Ge in a resonant 0 ν ECEC decay. We have also computed the associated nuclear matrix element by using a microscopic nuclear model with realistic two-nucleon interactions. The computed matrix element is found to be quite small. The failure of the resonant condition, combined with the small nuclear matrix element and needed p-wave capture, suppresses the decay rate strongly and thus excludes…

Syntheses of transuranium isotopes with atomic numbers Z≤ 103 in multi-nucleon transfer reactions

2015

Abstract In Section 1 we will discuss multi-nucleon transfer reactions with light heavy ions, which can be thought of as competing with complete fusion at higher impact parameters. Quasi-elastic and multi-nucleon transfer reactions with the heaviest projectiles will be discussed in Section 2 . In Section 3 we will cover recent developments focusing on theoretical predictions of cross sections of superheavy nuclei, cover some new possibilities and look into the existing experimental challenges.

First observation of the production of nucleon resonances in antiproton annihilation in liquid deuterium

1995

Strangeness of the nucleon

2005

Abstract Strangeness observables of the nucleon are discussed. Emphasis is put on the strange vector form factors as they are measured in current parity violating electron scattering experiments. Recent results are presented and the evidence for non-vanishing strangeness contributions is shown.

Determination of the S-wave pion nucleon scattering lengths from πN, pionic hydrogen and deuteron

2005

The isoscalar and isovector scattering lengths ( b 0 , b 1 ) are determined using a unitarized coupled channel approach based on chiral Lagrangians. For the deuterium scattering length a π − d new significant corrections are evaluated, putting new constraints from π − d scattering on the values of ( b 0 , b 1 ) .