First investigation of hypernuclei in reactions via analysis of emitted bremsstrahlung photons

Abstract

We investigate possibility of emission of bremsstrahlung photons in nuclear reactions with hypernuclei for the first time. A new model of bremsstrahlung emission which accompanies interactions between $\ensuremath{\alpha}$ particles and hypernuclei is constructed, where a new formalism for magnetic moments of nucleons and a hyperon inside a hypernucleus is added. To start calculations, we choose $\ensuremath{\alpha}$ decay of normal nucleus $^{210}\mathrm{Po}$ and hypernucleus $_{\mathrm{\ensuremath{\Lambda}}}^{211}\mathrm{Po}$. We find that (1) emission for the hypernucleus $_{\mathrm{\ensuremath{\Lambda}}}^{211}\mathrm{Po}$ is larger than for the normal nucleus $^{210}\mathrm{Po}$ and (2) the difference between these spectra is small. We propose a way to find the hypernuclei where the role of hyperon is the most essential in emission of the bremsstrahlung photons during $\ensuremath{\alpha}$ decay. As demonstration of such a property, we show that spectra for the hypernuclei $_{\mathrm{\ensuremath{\Lambda}}}^{107}\mathrm{Te}$ and $_{\mathrm{\ensuremath{\Lambda}}}^{109}\mathrm{Te}$ are essentially larger than the spectra for the normal nuclei $^{106}\mathrm{Te}$ and $^{108}\mathrm{Te}$. Such a difference is explained by additional contribution of emission to the full bremsstrahlung, which is formed by magnetic moment of hyperon inside hypernucleus. The bremsstrahlung emission formed by such a mechanism is of magnetic type. A new formula for fast estimations of bremsstrahlung spectra for even-even hypernuclei is proposed, where the role of the magnetic moment of the hyperon of the hypernucleus in formation of bremsstrahlung emission is shown explicitly. Then we applied our model to study bremsstrahlung emission in $\ensuremath{\alpha}$ decay of light hypernuclei $_{\mathrm{\ensuremath{\Lambda}}}^{10}\mathrm{Be}$ and $_{\mathrm{\ensuremath{\Lambda}}}^{10}\mathrm{B}$ (which was the subject of investigations at the Nuclotron at JINR, Dubna). Such an analysis opens the possibility of new experimental study of properties of the hypernuclei via bremsstrahlung study.