1,505 research outputs found
Renormalization of Higher Derivative Operators in the Matrix Model
-theory is believed to be described in various dimensions by large
field theories. It has been further conjectured that at finite , these
theories describe the discrete light cone quantization (DLCQ) of theory.
Even at low energies, this is not necessarily the same thing as the DLCQ of
supergravity. It is believed that this is only the case for quantities which
are protected by non-renormalization theorems. In 0+1 and 1+1 dimensions, we
provide further evidence of a non-renormalization theorem for the terms,
but also give evidence that there are not such theorems at order and
higher.Comment: 14 pages latex. Note added in light of recent development
Comment on Multigraviton Scattering in the Matrix Model
We show by explicit calculation that the matrix model effective action does
not contain the term , in the limit , contradicting a result reported recently.Comment: LaTex, 10 pages. Note added and minor correction
Gaugino condensation and the anomalous
We study gaugino condensation in presence of an anomalous gauge group
and find that global supersymmetry is dynamically broken. An example of
particular interest is provided by effective string models with 4-dimensional
Green-Schwarz anomaly cancellation mechanism. The structure of the hidden
sector is constrained by the anomaly cancellation conditions and the scale of
gaugino condensation is shifted compared with the usual case. We explicitly
compute the resulting soft supersymmetry breaking terms.Comment: 13 page
Implications of Low Energy Supersymmetry Breaking at the Tevatron
The signatures for low energy supersymmetry breaking at the Tevatron are
investigated. It is natural that the lightest standard model superpartner is an
electroweak neutralino, which decays to an essentially massless Goldstino and
photon, possibly within the detector. In the simplest models of gauge-mediated
supersymmetry breaking, the production of right-handed sleptons, neutralinos,
and charginos leads to a pair of hard photons accompanied by leptons and/or
jets with missing transverse energy. The relatively hard leptons and softer
photons of the single e^+e^- \gamma \gamma + \EmissT event observed by CDF
implies this event is best interpreted as arising from left-handed slepton pair
production. In this case the rates for l^{\pm} \gamma \gamma + \EmissT and
\gamma \gamma + \EmissT are comparable to that for l^+l^- \gamma \gamma +
\EmissT.Comment: 18 pages, Latex, tables correcte
Gluino Condensation in Strongly Coupled Heterotic String Theory
Strongly coupled heterotic string theory, compactified to
four dimensions on a large Calabi-Yau manifold , may represent a
viable candidate for the description of low-energy particle phenomenology. In
this regime, heterotic string theory is adequately described by low-energy
-theory on , with the two
's supported at the two boundaries of the world. In this paper we study
the effects of gluino condensation, as a mechanism for supersymmetry breaking
in this -theory regime. We show that when a gluino condensate forms in
-theory, the conditions for unbroken supersymmetry can still be satisfied
locally in the orbifold dimension . Supersymmetry is then
only broken by the global topology of the orbifold dimension, in a mechanism
similar to the Casimir effect. This mechanism leads to a natural hierarchy of
scales, and elucidates some aspects of heterotic string theory that might be
relevant to the stabilization of moduli and the smallness of the cosmological
constant.Comment: 22 pages, harvmac, no figure
Complex fermion mass term, regularization and CP violation
It is well known that the CP violating theta term of QCD can be converted to
a phase in the quark mass term. However, a theory with a complex mass term for
quarks can be regularized so as not to violate CP, for example through a zeta
function. The contradiction is resolved through the recognition of a dependence
on the regularization or measure. The appropriate choice of regularization is
discussed and implications for the strong CP problem are pointed out.Comment: REVTeX, 4 page
Low-thrust guidance study Final report
Computer algorithm to determine minimum-time optimal control for continuous low-thrust propulsion systems operating in inverse-square gravity fiel
Renormalization in General Gauge Mediation
We revisit General Gauge Mediation (GGM) in light of the supersymmetric
(linear) sigma model by utilizing the current superfield. The current
superfield in the GGM is identified with supersymmetric extension of the vector
symmetry current of the sigma model while spontaneous breakdown of
supersymmetry in the GGM corresponds to soft breakdown of the axial vector
symmetry of the sigma model. We first derive the current superfield from the
supersymmetric linear sigma model and then compute 2-point functions of the
current superfield using the (anti-)commutation relations of the messenger
component fields. After the global symmetry are weakly gauged, the 2-point
functions of the current superfield are identified with a part of the 2-point
functions of the associated vector superfield. We renormalize them by
dimensional regularization and show that physical gaugino and sfermion masses
of the MSSM are expressed in terms of the wavefunction renormalization
constants of the component fields of the vector superfield.Comment: 25 pages, 12 figure
Probing the SUSY breaking scale at an collider
If supersymmetry is spontaneously at a low energy scale then the resulting
gravitino would be very light. The interaction strength of the longitudinal
components of such a light gravitino to electron-selectron pair then becomes
comparable to that of electroweak interactions. Such a light gravitino could
modify the cross-section for e^_L e^_R-->\tilde {e}_L\tilde {e}_R from its
MSSM value. Precision measurement of this cross-section could therefore be used
to probe the low energy SUSY breaking scale.Comment: Plain Tex, 7 pages, No figure
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