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Your search keyword '"Meißner, U. G."' showing total 393 results
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393 results on '"Meißner, U. G."'

13. Gravitational p → ∆+ transition form factors in chiral perturbation theory.

Author

Alharazin, H., Sun, B.-D., Epelbaum, E., Gegelia, J., and Meißner, U.-G.

Subjects
CHIRAL perturbation theory, PROTON magnetic resonance, GRAVITATIONAL potential, CHIRALITY of nuclear particles
Abstract

The gravitational form factors of the transition from the proton to the ∆+ resonance are calculated to leading one-loop order using a manifestly Lorentz-invariant formulation of chiral perturbation theory. We take into account the leading electromagnetic and strong isospin-violating effects. The loop contributions to the transition form factors are found to be free of power-counting violating pieces, which is consistent with the absence of tree-level diagrams at the considered order. In this sense, our results can be regarded as predictions of chiral perturbation theory. [ABSTRACT FROM AUTHOR]

Published
2024
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36. On the structure in the $\Lambda N$ cross section at the $\Sigma N$ threshold

Author

Haidenbauer, J. and Meißner, U. -G.

Subjects
Nuclear Theory, Nuclear Experiment
Abstract

The complexity of threshold phenomena is exemplified on a prominent and long-known case - the structure in the $\Lambda p$ cross section (invariant mass spectrum) at the opening of the $\Sigma N$ channel. The mass splitting between the $\Sigma$ baryons together with the angular momentum coupling in the $^3S_1$-$^3D_1$ partial wave imply that, in principle, up to six channels are involved. Utilizing hyperon-nucleon potentials that provide an excellent description of the available low-energy $\Lambda p$ and $\Sigma N$ scattering data, the shape of the resulting $\Lambda p$ cross section is discussed and the poles near the $\Sigma N$ threshold are determined. Evidence for a strangeness $S=-1$ dibaryon is provided, in the form of a deuteron-like (unstable) $\Sigma N$ bound state. Predictions for level shifts and widths of $\Sigma^-p$ atomic states are given., Comment: 10 pages, 4 figures

Published
2021

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