On the Binding Energy and the Charge Symmetry Breaking in A<=16 Lambda-hypernuclei

TL;DR

This paper reviews recent high-precision measurements of Lambda-binding energies in hypernuclei with A<=16, analyzing charge symmetry breaking effects and comparing results from different experimental techniques.

Contribution

It reorganizes and critically compares recent spectrometric data, emphasizing the importance of absolute energy calibration for understanding charge symmetry breaking in hypernuclei.

Findings

B(Lambda) values are consistent within errors for A=7,12,16 isomultiplets.

Recent spectrometric data agree with theoretical predictions.

Proposes new measurements to improve current knowledge.

Abstract

In recent years, several experiments using magnetic spectrometers provided high precision results in the field of Hypernuclear Physics. In particular, the accurate determination of the Lambda-binding energy, B(Lambda), contributed to stimulate considerably the discussion about the Charge Symmetry Breaking effect in Lambda-hypernuclei isomultiplets. We have reorganized the results from the FINUDA experiment and we have obtained a series of B(Lambda) values for Lambda-hypernuclei with A <= 16 by taking into account data only from magnetic spectrometers implementing an absolute calibration of the energy scale (FINUDA at DAFNE and electroproduction experiments at JLab and at MaMi). We have then critically revisited the results obtained at KEK by the SKS Collaboration in order to make possible a direct comparison between data from experiments with and without such an absolute energy scale. A synopsis of recent spectrometric measurements of B(Lambda) is presented, including also emulsion experiment results. Several interesting conclusions are drawn, among which the equality within the errors of B(Lambda) for the A = 7, 12, 16 isomultiplets, based only on recent spectrometric data. This observation is in nice agreement with a recent theoretical prediction. Ideas for possible new measurements which should improve the present experimental knowledge are finally put forward.