133 research outputs found
Virtual Supersymmetric Corrections in e^+e^- Annihilation
Depending on their masses, Supersymmetric particles can affect various
measurements in Z decay. Among these are the total width (or consequent
extracted value of ), enhancement or suppression of various flavors,
and left-right and forward-backward asymmetries. The latter depend on squark
mass splittings and are, therefore, a possible test of the Supergravity related
predictions. We calculate leading order corrections for these quantities
considering in particular the case of light photino and gluino where the SUSY
effects are enhanced. In this limit the effect on is appreciable,
the effect on is small, and the effect on the asymmetries is extremely
small.Comment: 11 pages, LaTeX, 3 figures, revised, a reference adde
Nuclear Physics in a Susy Universe
We refine a previous zeroth order analysis of the nuclear properties of a
supersymmetric (susy) universe with standard model particle content plus
degenerate susy partners. No assumptions are made concerning the Higgs
structure except we assume that the degenerate fermion/sfermion masses are
non-zero. This alternate universe has been dubbed Susyria and it has been
proposed that such a world may exist with zero vacuum energy in the string
landscape.Comment: 8 pages, 1 figur
Decay into Light Gluinos
Flavor changing interactions of the gluino allow the quark to decay into
the strange quark plus a gluino pair if the gluino is in the ultra low mass
window below 1 GeV. In this case the enhancement of the nonleptonic decay
could explain the anomalous semileptonic branching ratio.Comment: 10 pages, REVTEX, 2 Postscript figure
A supersymmetric model of gamma ray bursts
We propose a model for gamma ray bursts in which a star subject to a high
level of fermion degeneracy undergoes a phase transition to a supersymmetric
state. The burst is initiated by the transition of fermion pairs to sfermion
pairs which, uninhibited by the Pauli exclusion principle, can drop to the
ground state of minimum momentum through photon emission. The jet structure is
attributed to the Bose statistics of sfermions whereby subsequent sfermion
pairs are preferentially emitted into the same state (sfermion amplification by
stimulated emission). Bremsstrahlung gamma rays tend to preserve the
directional information of the sfermion momenta and are themselves enhanced by
stimulated emission.Comment: published versio
An Alternative String Landscape Cosmology: Eliminating Bizarreness
In what has become a standard eternal inflation picture of the string
landscape there are many problematic consequences and a difficulty defining
probabilities for the occurrence of each type of universe. One feature in
particular that might be philosophically disconcerting is the infinite cloning
of each individual and each civilization in infinite numbers of separated
regions of the multiverse. Even if this is not ruled out due to causal
separation one should ask whether the infinite cloning is a universal
prediction of string landscape models or whether there are scenarios in which
it is avoided. If a viable alternative cosmology can be constructed one might
search for predictions that might allow one to discriminate experimentally
between the models. We present one such scenario although, in doing so, we are
forced to give up several popular presuppositions including the absence of a
preferred frame and the homogeneity of matter in the universe. The model also
has several ancillary advantages. We also consider the future lifetime of the
current universe before becoming a light trapping region.Comment: 13 pages, 1 figure, minor clarifications in version
A supersymmetric model for triggering Supernova Ia in isolated white dwarfs
We propose a model for supernovae Ia explosions based on a phase transition
to a supersymmetric state which becomes the active trigger for the deflagration
starting the explosion in an isolated sub-Chandrasekhar white dwarf star. With
two free parameters we fit the rate and several properties of type Ia
supernovae and address the gap in the supermassive black hole mass
distribution. One parameter is a critical density fit to about
g/cc while the other has the units of a space time volume and is found to be of
order Gyr where is the earth radius. The model involves
a phase transition to an exact supersymmetry in a small core of a dense star.Comment: 20 pages, 5 figures, expanded version to be published in Physical
Review
Higgs and Z boson decays into light gluinos
We calculate the decay rate of scalar and pseudoscalar Higgs bosons into a
pair of gluinos, within the Minimal Supersymmetric Standard Model. In the
theoretically and experimentally allowed light gluino window, \mg \sim 3--5
GeV, gluino pairs can completely dominate the decays of the light scalar Higgs
boson and play a prominent role in the decay of the pseudoscalar Higgs boson.
This would alter the limits obtained from decays on the lightest CP--even
and CP--odd Higgs bosons, and could jeopardize the search for these Higgs
particles at future hadron colliders. In contrast, the branching ratio for the
two--body decay of bosons into pairs of light gluinos is less than 0.1\%.Comment: Latex file, 16 pages of text. 8 uufiled postscript figures included.
Compressed postscript version with figures available by anonymous ftp at
ftp://phenom.physics.wisc.edu/pub/preprints/current/madph-94-853.ps.
Z decays into light gluinos: a calculation based on unitarity
The Z boson can decay to a pair of light gluinos through loop-mediated
processes. Based on unitarity of the S-matrix, the imaginary part of the decay
amplitude is computed in the presence of a light bottom squark. This imaginary
part can provide useful information on the full amplitude. Implications are
discussed for a recently proposed light gluino and light bottom squark
scenario.Comment: 19 pages, LaTeX, 3 figures, submitted to Phys. Rev.
New Signatures of Squarks
When the gluino is light and long lived, missing energy is a poor signature
for both squarks and gluinos. Instead, production in and
collisions characteristically results in events with jets.
Methods are proposed for deciding whether an observed excess of 4-jet events is
due to production. The recent report by ALEPH of observation of 14
4-jet events when 7 were expected is discussed.Comment: 12/22/95 version (put on net 1/1/96) elaborates remarks on squarks as
possible source of ALEPH 4-jet excess and adds a ref. latex, 10 pages
(including 1 figure), uufile
One-Loop Amplitudes for e^+ e^- to Four Partons
We present the first explicit formulae for the complete set of one-loop
helicity amplitudes necessary for computing next-to-leading order corrections
for e^+ e^- annihilation into four jets, for W, Z or Drell-Yan production in
association with two jets at hadron colliders, and for three-jet production in
deeply inelastic scattering experiments. We include a simpler form of the
previously published amplitudes for e^+ e^- to four quarks. We obtain the
amplitudes using their analytic properties to constrain their form.
Systematically eliminating spurious poles from the amplitudes leads to
relatively compact results.Comment: Tex, 82 pages, Maple and Mathematica files containing the amplitudes
are available from the author
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