28 research outputs found
Charge and Magnetic Properties of Three-Nucleon Systems in Pionless Effective Field Theory
A method to calculate the form factor for an external current with
non-derivative coupling for the three-body system in an effective field theory
(EFT) of short-range interactions is shown. Using this method the point charge
radius of is calculated to next-to-next-to-leading order
(NNLO) in pionless EFT (), and the magnetic moment
and magnetic radius of and are calculated to
next-to-leading order (NLO). For the charge and magnetic form
factors Coulomb interactions are ignored. The point charge
radius is given by 1.74(4) fm at NNLO. This agrees well with the experimental
point charge radius of 1.7753(54) fm [Angeli and Marinova,
At. Data Nucl. Data Tables 99, 69 (2013)]. The
() magnetic moment in units of nuclear magnetons is found to
be 2.92(35) (-2.08(25)) at NLO in agreement with the experimental value of
2.979 (-2.127). For () the NLO magnetic
radius is 1.78(11) fm (1.85(11) fm) which agrees with the experimental value of
1.840(182) fm (1.965(154) fm) [I. Sick, Prog. Part. Nucl. Phys. 47, 245
(2001)]. The fitting of the low-energy constant of the isovector
two-body magnetic current and the consequences of Wigner-SU(4) symmetry for the
three-nucleon magnetic moments are also discussed.Comment: v1: 38 pages 6 figure
Time-Reversal-Invariance Violation in the System and Large-
A minimal set of five low energy constants (LECs) for time-reversal and
parity violating () nucleon-nucleon () interactions
at low energies () is given. Using a large- (number
of colors in QCD) analysis we show that one linear combination of LECs is
, three LECs are , and one linear
combination of LECs is . We also calculate the
observables of neutron spin rotation through a polarized
deuteron target and a spin correlation coefficient in nucleon-deuteron
scattering using pionless effective field theory. Using the large-
analysis we show that the spin correlation coefficient and the neutron spin
rotation are predominantly determined by same two LECs in the large-
basis.Comment: 21 pages, 3 figure
Generalized Pauli principle for particles with distinguishable traits
The s=3/2 Ising spin chain with uniform nearest-neighbor coupling, quadratic
single-site potential, and magnetic field is shown to be equivalent to a system
of 17 species of particles with internal structure. The same set of particles
(with different energies) is shown to generate the spectrum of the s=1/2 Ising
chain with dimerized nearest-neighbor coupling. The particles are free of
interaction energies even at high densities. The mutual exclusion statistics of
particles from all species is determined by their internal structure and
encoded in a generalized Pauli principle. The exact statistical mechanical
analysis can be performed for thermodynamically open or closed systems and with
arbitrary energies assigned to all particle species. Special circumstances make
it possible to merge two or more species into a single species. All traits that
distinguish the original species become ignorable. The particles from the
merged species are effectively indistinguishable and obey modified exclusion
statistics. Different mergers may yield the same endproduct, implying that the
inverse process (splitting any species into subspecies) is not unique. In a
macroscopic system of two merged species at thermal equilibrium, the
concentrations of the original species satisfy a functional relation governed
by their mutual statistical interaction. That relation is derivable from an
extremum principle. In the Ising context the system is open and the particle
energies depend on the Hamiltonian parameters. Simple models of polymerization
and solitonic paramagnetism each represent a closed system of two species that
can transform into each other. Here they represent distinguishable traits with
different energies of the same physical particle.Comment: 12 pages, 7 figures, 6 table