14,657 research outputs found
Could we learn more about HERA high anomaly from LEP200 and TEVATRON? R-parity violation scenario
The excess of high events at HERA reported in the early 1997 by H1 and
ZEUS collaborations has become the subject of extensive studies in the
framework of several models related to new physics. Here we concentrate on the
most promising, from our point of view, model describing HERA anomaly. We
update our previous analysis and take into account new HERA statistics of the
1997 year. HERA events are considered within the R-parity broken SUSY model for
a specific scenario with several non-zero couplings. R-parity broken SUSY with
several non-zero couplings could explain both high and observed at HERA. The consequence of such a particular scenario is the
excess of high di- or tri-jet events at HERA. The relation of this
scenario for LEP and TEVATRON colliders is considered. This study shows that if
a squark resonance does take place at HERA, supersymmetry with broken R-parity
can be revealed at either LEP200 or TEVATRON in the near future.Comment: 15 pages, LaTeX file with 9 eps figure
Minimal Supersymmetric Standard Model within CompHEP software package
The Minimal Supersymmetric Standard Model is presented as a model for the
CompHEP software package as a set of files containing the complete Lagrangian
of the MSSM, particle contents and parameters. All resources of CompHEP with a
user-friendly interface are now available for the phenomenological study of the
MSSM. Various special features of the model are discussed.Comment: 11 pages, LaTeX, submitted to Comp. Phys. Communicatio
Brane-Localized Goldstone Fermions in Bulk Supergravity
We construct the action and transformation laws for bulk five-dimensional AdS
supergravity coupled to one or two brane-localized Goldstone fermions. The
resulting bulk-plus-brane system gives a model-independent description of
brane-localized supersymmetry breaking in the Randall-Sundrum scenario. We
explicitly reduce the action and transformation laws to spontaneously broken
four-dimensional supergravity.Comment: 22 page
Magnetic Moments of Heavy Baryons in Light Cone QCD Sum Rules
The magnetic moments of heavy baryons containing a single charm or
bottom quark are calculated in the framework of light cone QCD sum rules
method. A comparison of our results with the predictions of the quark models is
presented.Comment: 26 Pages, 8 Figures and 1 Tabl
Positive and negative-parity flavor-octet baryons in coupled QCD sum rules
We apply the method of the QCD sum rule, in which positive- and
negative-parity baryons couple with each other, to the flavor-octet hyperons
and investigate the parity splittings. We also reexamine the nucleon in the
method, which was studied in our previous paper, by carefully choosing the
Borel weight. Both in the nucleon and hyperon channels the obtained sum rules
turn out to have a very good Borel stability and also have a Borel window, an
energy region in which the OPE converges and the pole contribution dominates
over the continuum contribution. The predicted masses of the positive- and
negative-parity baryons reproduce the experimental ones fairly well in the
and channels, if we assign the and the
to the parity partners of the and the ,
respectively. This implies that the is not the party partner of
the and may be a flavor-singlet or exotic state. In the
channel, the sum rule predicts the mass of the negative-parity state to be
about 1.8 GeV, which leads to two possibilities; one is that the observed state
with the closest mass, , is the parity partner and the other is that
the parity partner is not yet found but exists around 1.8 GeV.Comment: 15 pages, 4 figure
Perturbation of a lattice spectral band by a nearby resonance
A soluble model of weakly coupled "molecular" and "nuclear" Hamiltonians is
studied in order to exhibit explicitly the mechanism leading to the enhancement
of fusion probability in case of a narrow near-threshold nuclear resonance. We,
further, consider molecular cells of this type being arranged in lattice
structures. It is shown that if the real part of the narrow nuclear resonance
lies within the molecular band generated by the intercellular interaction, an
enhancement, proportional to the inverse width of the nuclear resonance, is to
be expected.Comment: RevTeX, 2 figures within the file. In May 2000 the title changed and
some minor corrections have been don
Light-cone sum rules for the transitions for real photons
We examine the radiative transition at the real photon
point using the framework of light-cone QCD sum rules. In particular,
the sum rules for the transition form factors and are
determined up to twist 4. The result for agrees with experiment within
10% accuracy. The agreement for is also reasonable. In addition, we
derive new light-cone sum rules for the magnetic moments of nucleons, with a
complete account of twist-4 corrections based on a recent reanalysis of photon
distribution amplitudes.Comment: 34 pages, 9 figures, revised version, published in Phys. Rev. D, one
misplaced reference correcte
Rigid supersymmetry with boundaries
We construct rigidly supersymmetric bulk-plus-boundary actions, both in
-space and in superspace. For each standard supersymmetric bulk action a
minimal supersymmetric bulk-plus-boundary action follows from an extended -
or -term formula. Additional separately supersymmetric boundary actions can
be systematically constructed using co-dimension one multiplets (boundary
superfields). We also discuss the orbit of boundary conditions which follow
from the Euler-Lagrange variational principle.Comment: 28 pages, JHEP clas
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