46,348 research outputs found
Weak boson fusion production of supersymmetric particles at the LHC
We present a complete calculation of weak boson fusion production of
colorless supersymmetric particles at the LHC, using the new matrix element
generator SUSY-MadGraph. The cross sections are small, generally at the
attobarn level, with a few notable exceptions which might provide additional
supersymmetric parameter measurements. We discuss in detail how to consistently
define supersymmetric weak couplings to preserve unitarity of weak gauge boson
scattering amplitudes to fermions, and derive sum rules for weak supersymmetric
couplings.Comment: 24 p., 3 fig., 9 tab., published in PRD; numbers in Table IV
corrected to those with kinematic cuts cite
The Anisotropy of MHD Alfv\'{e}nic Turbulence
We perform direct 3-dimensional numerical simulations for magnetohydrodynamic
(MHD) turbulence in a periodic box of size threaded by strong uniform
magnetic fields. We use a pseudo-spectral code with hyperviscosity and
hyperdiffusivity to solve the incompressible MHD equations. We analyze the
structure of the eddies as a function of scale. A straightforward calculation
of anisotropy in wavevector space shows that the anisotropy is scale-{\it
independent}. We discuss why this is {\it not} the true scaling law and how the
curvature of large-scale magnetic fields affects the power spectrum and leads
to the wrong conclusion. When we correct for this effect, we find that the
anisotropy of eddies depends on their size: smaller eddies are more elongated
than larger ones along {\it local} magnetic field lines. The results are
consistent with the scaling law proposed by Goldreich and Sridhar (1995, 1997). Here
(and ) are wavenumbers measured relative to
the local magnetic field direction. However, we see some systematic deviations
which may be a sign of limitations to the model, or our inability to fully
resolve the inertial range of turbulence in our simulations.Comment: 13 pages (11 NEW figures), ApJ, in press (Aug 10, 2000?
Aspects of Electric and Magnetic Variables in SU(2) Yang-Mills Theory
We introduce a novel decomposition of the four dimensional SU(2) gauge field.
This decomposition realizes explicitely a symmetry between electric and
magnetic variables, suggesting a duality picture between the corresponding
phases. It also indicates that at large distances the Yang-Mills theory
involves a three component unit vector field, a massive Lorentz vector field,
and a neutral scalar field that condenses which yields the mass scale. Our
results are consistent with the proposal that the physical spectrum of the
theory contains confining strings which are tied into stable knotted solitons.Comment: we have made substantial improvement
Comment on Decay
We calculate the rate for decay using Chiral
Perturbation Theory. This isospin violating process results from -
mixing, and its amplitude is proportional to . Experimental information on the branching
ratio for can provide insight into the pattern of
violation in radiative decays.Comment: 7 pages with 2 figures not included but available upon request,
CALT-68-191
Abelian Dominance in Wilson Loops
It has been conjectured that the Abelian projection of QCD is responsible for
the confinement of color. Using a gauge independent definition of the Abelian
projection which does {\it not} employ any gauge fixing, we provide a strong
evidence for the Abelian dominance in Wilson loop integral. In specific we
prove that the gauge potential which contributes to the Wilson loop integral is
precisely the one restricted by the Abelian projection.Comment: 4 pages, no figure, revtex. Phys. Rev. D in pres
Phonotactics vs. phonetic cues in native and non-native listening: Dutch and Korean listeners' perception of Dutch and English
We investigated how listeners of two unrelated languages, Dutch and Korean, process phonotactically legitimate and illegitimate sounds spoken in Dutch and American English. To Dutch listeners, unreleased word-final stops are phonotactically illegal because word-final stops in Dutch are generally released in isolation, but to Korean listeners, released final stops are illegal because word-final stops are never released in Korean. Two phoneme monitoring experiments showed a phonotactic effect: Dutch listeners detected released stops more rapidly than unreleased stops whereas the reverse was true for Korean listeners. Korean listeners with English stimuli detected released stops more accurately than unreleased stops, however, suggesting that acoustic-phonetic cues associated with released stops improve detection accuracy. We propose that in non-native speech perception, phonotactic legitimacy in the native language speeds up phoneme recognition, the richness of acousticphonetic cues improves listening accuracy, and familiarity with the non-native language modulates the relative influence of these two factors
Partially Dual variables in SU(2) Yang-Mills Theory
We propose a reformulation of SU(2) Yang-Mills theory in terms of new
variables. These variables are appropriate for describing the theory in its
infrared limit, and indicate that it admits knotlike configurations as stable
solitons. As a consequence we arrive at a dual picture of the Yang-Mills theory
where the short distance limit describes asymptotically free, massless point
gluons and the large distance limit describes extended, massive knotlike
solitons.Comment: 4 pages, revtex twocolum
Magnetic Moments of Heavy Baryons
First non-trivial chiral corrections to the magnetic moments of triplet (T)
and sextet (S^(*)) heavy baryons are calculated using Heavy Hadron Chiral
Perturbation Theory. Since magnetic moments of the T-hadrons vanish in the
limit of infinite heavy quark mass (m_Q->infinity), these corrections occur at
order O(1/(m_Q \Lambda_\chi^2)) for T-baryons while for S^(*)-baryons they are
of order O(1/\Lambda_\chi^2). The renormalization of the chiral loops is
discussed and relations among the magnetic moments of different hadrons are
provided. Previous results for T-baryons are revised.Comment: 11 Latex pages, 2 figures, to be published in Phys.Rev.
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