69,508 research outputs found
Satellite motion for all inclinations around an oblate planet
Satellite motion for all inclinations around oblate plane
Resonant tunneling in fractional quantum Hall effect: superperiods and braiding statistics
We study theoretically resonant tunneling of composite fermions through their
quasi-bound states around a fractional quantum Hall island, and find a rich set
of possible transitions of the island state as a function of the magnetic field
or the backgate voltage. These considerations have possible relevance to a
recent experimental study, and bring out many subtleties involved in deducing
fractional braiding statistics.Comment: Phys. Rev. Lett. in pres
Flavour symmetry breaking in the kaon parton distribution amplitude
We compute the kaon's valence-quark (twist-two parton) distribution amplitude
(PDA) by projecting its Poincare'-covariant Bethe-Salpeter wave-function onto
the light-front. At a scale \zeta=2GeV, the PDA is a broad, concave and
asymmetric function, whose peak is shifted 12-16% away from its position in
QCD's conformal limit. These features are a clear expression of
SU(3)-flavour-symmetry breaking. They show that the heavier quark in the kaon
carries more of the bound-state's momentum than the lighter quark and also that
emergent phenomena in QCD modulate the magnitude of flavour-symmetry breaking:
it is markedly smaller than one might expect based on the difference between
light-quark current masses. Our results add to a body of evidence which
indicates that at any energy scale accessible with existing or foreseeable
facilities, a reliable guide to the interpretation of experiment requires the
use of such nonperturbatively broadened PDAs in leading-order, leading-twist
formulae for hard exclusive processes instead of the asymptotic PDA associated
with QCD's conformal limit. We illustrate this via the ratio of kaon and pion
electromagnetic form factors: using our nonperturbative PDAs in the appropriate
formulae, at spacelike-, which compares
satisfactorily with the value of inferred in annihilation
at .Comment: 7 pages, 2 figures, 3 table
The time-history of a satellite around an oblate planet
Time history of satellite around oblate plane
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