Abstract
Michael Atiyah’s interest in Skyrmions and their relationship to monopoles and instantons is recalled. Some approximate models of Skyrmions with large baryon numbers are then considered. ...Skyrmions having particularly strong binding are clusters of unit baryon number Skyrmions arranged as truncated tetrahedra. Their baryon numbers, $B = 4 \,, 16 \,, 40 \,, 80 \,, 140 \,, 224$, are the tetrahedral numbers multiplied by four, agreeing with the magic proton and neutron numbers $2 \,, 8 \,, 20 \,, 40 \,, 70 \,, 112$ occurring in the nuclear shell model in the absence of strong spin-orbit coupling.
Nemaline myopathy (NM) is a rare congenital muscle disorder primarily affecting skeletal muscles that results in neonatal death in severe cases as a result of associated respiratory insufficiency. NM ...is thought to be a disease of sarcomeric thin filaments as six of eight known genes whose mutation can cause NM encode components of that structure, however, recent discoveries of mutations in non-thin filament genes has called this model in question. We performed whole-exome sequencing and have identified recessive small deletions and missense changes in the Kelch-like family member 41 gene (KLHL41) in four individuals from unrelated NM families. Sanger sequencing of 116 unrelated individuals with NM identified compound heterozygous changes in KLHL41 in a fifth family. Mutations in KLHL41 showed a clear phenotype-genotype correlation: Frameshift mutations resulted in severe phenotypes with neonatal death, whereas missense changes resulted in impaired motor function with survival into late childhood and/or early adulthood. Functional studies in zebrafish showed that loss of Klhl41 results in highly diminished motor function and myofibrillar disorganization, with nemaline body formation, the pathological hallmark of NM. These studies expand the genetic heterogeneity of NM and implicate a critical role of BTB-Kelch family members in maintenance of sarcomeric integrity in NM.
The low-energy dynamics of any system admitting a continuum of static configurations is approximated by slow motion in moduli (configuration) space. Here, following Ferrell and Eardley, this moduli ...space approximation is utilized to study collisions of two maximally charged Reissner-Nordström black holes of arbitrary masses, and to compute analytically the gravitational radiation generated by their scattering or coalescence. The motion remains slow even though the fields are strong, and the leading radiation is quadrupolar. A simple expression for the gravitational waveform is derived and compared at early and late times to expectations.
We compute the nuclear spin-orbit coupling from the Skyrme model. Previous attempts to do this were based on the product ansatz, and as such were limited to a system of two well-separated nuclei. Our ...calculation utilises a new method, and is applicable to the phenomenologically important situation of a single nucleon orbiting a large nucleus. We find that, to second order in perturbation theory, the coefficient of the spin-orbit coupling induced by pion field interactions has the wrong sign, but as the strength of the pion-nucleon interactions increases the correct sign is recovered non-perturbatively.
Classically spinning B=1 Skyrmions can be regarded as approximations to nucleons with quantised spin. Here, we investigate nucleon–nucleon scattering through numerical collisions of spinning ...Skyrmions. We identify the dineutron/diproton and dibaryon short-lived resonance states, and also the stable deuteron state. Our simulations lead to predictions for the polarisation states occurring in right angle scattering.
A
bstract
In this paper we propose ALF gravitational instantons of types
A
k
and
D
k
as models for charged particle systems. We calculate the charges of the two families. These are −(
k
+ 1) for
A
k
..., which is proposed as a model for
k
+ 1 electrons, and 2 −
k
for
D
k
, which is proposed as a model for either a particle of charge +2 and
k
electrons or a proton and
k
− 1 electrons. Making use of preferred topological and metrical structures of the manifolds, namely metrically preferred representatives of middle dimension homology classes, we construct two different energy functionals which reproduce the Coulomb interaction energy for a system of charged particles.
Skyrmions and the α-particle model of nuclei Battye, Richard A; Manton, Nicholas S; Sutcliffe, Paul M
Proceedings of the Royal Society. A, Mathematical, physical, and engineering sciences,
01/2007, Letnik:
463, Številka:
2077
Journal Article
Recenzirano
Odprti dostop
We compute new solutions of the Skyrme model with massive pions. Concentrating on baryon numbers which are multiples of four, we find low-energy Skyrmion solutions that are composed of charge four ...subunits, as in the α-particle model of nuclei. We summarize our current understanding of these solutions, and discuss their relationship to configurations in the α-particle model.
PDF
