47 research outputs found
Aharonov-Bohm Problem for Spin-One
The basic AB problem is to determine how an unshielded tube of magnetic flux
affects arbitrarily long-wavelength charged particles impinging on it.
For spin-1 at almost all the particles do not penetrate the tube, so the
interaction essentially is periodic in (AB effect). Below-threshold
bound states move freely only along the tube axis, and consequent induced
vacuum currents supplement rather than screen . For a pure magnetic
interaction the tube must be broader than the particle Compton wavelength,
i.e., only the nonrelativistic spin-1 AB problem exists.Comment: 15 pages, Late
Ridge Production in High-Multiplicity Hadronic Ultra-Peripheral Proton-Proton Collisions
An unexpected result at the RHIC and the LHC is the observation that
high-multiplicity hadronic events in heavy-ion and proton-proton collisions are
distributed as two "ridges", approximately flat in rapidity and opposite in
azimuthal angle. We propose that the origin of these events is due to the
inelastic collisions of aligned gluonic flux tubes that underly the color
confinement of the quarks in each proton. We predict that high-multiplicity
hadronic ridges will also be produced in the high energy photon-photon
collisions accessible at the LHC in ultra-peripheral proton-proton collisions
or at a high energy electron-positron collider. We also note the orientation of
the flux tubes between the quark and antiquark of each high energy photon will
be correlated with the plane of the scattered proton or lepton. Thus hadron
production and ridge formation can be controlled in a novel way at the LHC by
observing the azimuthal correlations of the scattering planes of the
ultra-peripheral protons with the orientation of the produced ridges.
Photon-photon collisions can thus illuminate the fundamental physics underlying
the ridge effect and the physics of color confinement in QCD.Comment: Presented by SJB at Photon 2017: The International Conference on the
Structure and the Interactions of the Photon and the International Workshop
on Photon-Photon Collisions. CERN, May 22-26, 2017. References adde
Traces of Theta^+ pentaquark in K^+ nucleus dynamics
Long-standing anomalies in K^+ nucleus integral cross sections could be
resolved by extending the impulse-approximation t*rho optical-potential
framework to incorporate K^+ absorption on pairs of nucleons. Substantially
improved fits to the data at p(lab)=500-700 MeV/c are obtained. An upper bound
of 3.5 mb for the absorption cross section of K^+ per nucleon is derived. We
conjecture that the underlying microscopic absorption process is K^+ n N -->
Theta^+ N, where Theta^+(1540) is the newly discovered exotic Y=2, I=0, Z=1
pentaquark baryon, and estimate that the cross section for K^+ d --> Theta^+ p
is a fraction of millibarn. Comments are made on Theta^+ production reactions
on nuclei.Comment: 4 double-column pages, 1 figure, extended results and discussion,
final form accepted for publication in PR
Characterization of fractional-quantum-Hall-effect quasiparticles
Composite fermions in a partially filled quasi-Landau level may be viewed as
quasielectrons of the underlying fractional quantum Hall state, suggesting that
a quasielectron is simply a dressed electron, as often is true in other
interacting electron systems, and as a result has the same intrinsic charge and
exchange statistics as an electron. This paper discusses how this result is
reconciled with the earlier picture in which quasiparticles are viewed as
fractionally-charged fractional-statistics ``solitons". While the two
approaches provide the same answers for the long-range interactions between the
quasiparticles, the dressed-electron description is more conventional and
unifies the view of quasiparticle dynamics in and beyond the fractional quantum
Hall regime.Comment: 11 pages, latex, no figure
Effect of Hadron Dynamics on the Proton Lifetime
A detailed, quantitative re-examination of the effect of hadron dynamics on
baryon decay, modeled in terms of Skyrme-field tunneling, indicates that any
hadronic suppression should be quite mild. This appears to be another
illustration of the `Cheshire-cat' phenomenon, that variation of the
apportionment between description of the nucleon as a bag of quarks and
description as a Skyrme field configuration has little influence on many
nucleon properties. Perhaps the largest remaining uncertainty in evaluating the
decay rate has to do with the overlap between a specified quark-antiquark
configuration and a final meson state.Comment: minor corrections, 19 pages, 9 figure
Confinement, Crossing Symmetry, and Glueballs
We suggest that the quark-confining force is related by crossing symmetry to
a color-singlet glueball which is well described as a loop of one
quantum of color magnetic flux. Electron pair annihilation as high as above the mass could produce accompanied by or one of its excited states.Comment: LaTeX, 12 pages, no figures, Los Alamos preprint LA-UR-94-263
AB and Berry phases for a quantum cloud of charge
We investigate the phase accumulated by a charged particle in an extended
quantum state as it encircles one or more magnetic fluxons, each carrying half
a flux unit. A simple, essentially topological analysis reveals an interplay
between the Aharonov-Bohm phase and Berry's phase.Comment: 10 pages, TAUP 2110-93. Te