Decays, contact P-wave interactions and hyperfine structure in Omega- exotic atoms

Abstract

Contact $P$-wave interactions connected to the Larmor interaction of a magnetic dipole and Thomas spin precession in the filed of an electric quadrupole are described and their implications for spectroscopy of exotic ${\Omega }^{-}$-atoms are studied. In order to evaluate the magnitude of the contact $P$-wave interactions as compared to the conventional long-range interactions and the sensitivity of spectroscopic data to the ${\Omega }^{-}$-hyperon quadrupole moment, we consider $2P$ states of ${\Omega }^{-}$ atoms formed with light stable nuclei with spins $I\ge 1/2$ and atomic numbers $Z\le 10$. The energy level splitting caused by the contact interactions is 2-5 orders of magnitude smaller than the conventional long-range interactions. Strong decay widths of $p{\Omega }^{-}$ atoms due to reactions $p{\Omega }^{-}\to \Lambda {\Xi }^0$ and $p{\Omega }^{-}\to \Sigma \Xi$, induced by $t$-channel kaon exchanges, are calculated. ${\Omega }^{-}$ atoms formed with the light nuclei have strong widths 5-6 orders of magnitude higher than splitting caused by the contact interactions. The low-$L$ pattern in the energy spectra of intermediate- and high-$Z$ ${\Omega }^{-}$ atoms thus cannot be observed. The ${\Omega }^{-}$ quadrupole moment can be measured by observing $X$-rays from circular transitions between high-$L$ levels in ${\Omega }^{-}$ exotic atoms. The effect of strong interactions in ${}^{208}$Pb${\Omega }^{-}$ atoms is negligible starting from $L\sim 10$. The contact $P$-wave interactions exist in ordinary atoms and $\mu$-meson atoms.

LaTeX 49 pages, 3 eps figures, replaced with published version

References in corpus (1)

• Light baryon magnetic moments and N -> Delta gamma transition in a Lorentz covariant chiral quark approach