B=5 Skyrmion as a two-cluster system

Abstract

The classical B ¼ 5 Skyrmion can be approximated by a two-cluster system in which a B ¼ 1 Skyrmion is attached to a core B ¼ 4 Skyrmion. We quantize this system, allowing the B ¼ 1 to freely orbit the core. The configuration space is 11 dimensional but simplifies significantly after factoring out the overall spin and isospin degrees of freedom. We exactly solve the free quantum problem and then include an interaction potential between the Skyrmions numerically. The resulting energy spectrum is compared to the corresponding nuclei-the helium-5/lithium-5 isodoublet. We find approximate parity doubling not seen in the experimental data. In addition, we fail to obtain the correct ground-state spin. The framework laid out for this two-cluster system can readily be modified for other clusters and in particular for other B ¼ 4n þ 1 nuclei, of which B ¼ 5 is the simplest example.

Rolling Skyrmions and the nuclear spin-orbit force

“…Our analysis also sheds light on a recent study of a B = 1 Skyrmion orbiting a B = 4 core [17]. It was found that weak pion-induced coupling to the core affects the energy levels of the orbiting Skyrmion, but in the opposite way to what would be expected based on the phenomenological spin-orbit coupling.…”

“…This is consistent with our perturbative result for the spin-momentum coupling, and a similar problem will likely persist for larger baryon numbers. We suggest that the correct sign of the spinorbit coupling will be obtained for stronger potentials, and that a non-perturbative treatment will resolve some of the puzzles in [17].…”

Realistic classical binding energies in the ω-Skyrme model

“…The traditional approach is "rigid body quantisation", in which the action of the field theory is restricted to the spin-isospin orbit of a degree B classical energy minimiser. Recent studies of the standard Skyrme model suggest that this is, for B > 1, often too restrictive: the Skyrme field should instead be restricted (for each fixed t) to lie in some finite dimensional manifold M of configurations which includes the spin-isospin orbits of the global energy minimiser and all nearby local minima, and field configurations interpolating between these [29][30][31][32][33][34]. In general, determining M is a difficult task, more art than science at present.…”

Optical dispersion of composite particles consisting of millicharged constituents

“…In fact, we found that dispersion due to matter effects was irrelevant until energies around 10 29 GeV. But composite DM models might prove to be more reactive, particularly if the DM is comprised of charged constituents [29,30,35,37,42,44,45,47,48,50,52,53,58,59].…”

“…Millicharged atomic DM represents only a fraction of proposed composite DM models. Many models posit composite states strongly bound by a nonabelian gauge force [28-30, 33-35, 37, 40-42, 44, 46, 47, 49-52, 54-58, 60], some of which contain electrically charged constituents [29,30,35,37,42,44,47,50,52,58]. The details of these strongly composite systems with charged constituents are model dependent, so we will only sketch an approach as to how one would estimate the susceptibility of such a DM medium.…”