13,702 research outputs found
Nonlinear Realization of Supersymmetric AdS Space Isometries
The isometries of space and supersymmetric space
are nonlinearly realized on four dimensional Minkowski space. The resultant
effective actions in terms of the Nambu-Goldstone modes are constructed. The
dilatonic mode governing the motion of the Minkowski space probe brane into the
covolume of supersymmetric space is found to be unstable and the bulk
of the space is unable to sustain the brane. No such instablility
appears in the non-supersymmetric case.Comment: 18 page
Nonlinear Realization of Supersymmetry and Superconformal Symmetry
Nonlinear realizations describing the spontaneous breakown of supersymmetry
and R symmetry are constructed using the Goldstino and R axion fields. The
associated R current, supersymmetry current and energy-momentum tensor are
shown to be related under the nonlinear supersymmetry transformations.
Nonlinear realizations of the superconformal algebra carried by these degrees
of freedom are also displayed. The divergences of the R and dilatation currents
are related to the divergence of the superconformal currents through nonlinear
supersymmetry transformations which in turn relates the explicit breakings of
these symmetries.Comment: 22 pages, LaTe
The Supercurrent In Supersymmetric Field Theories
A supercurrent superfield whose components include a conserved
energy-momentum tensor and supersymmetry current as well as a (generally
broken) R-symmetry current is constructed for a generic effective N=1
supersymmetric gauge theory. The general form of the R-symmetry breaking is
isolated. Included within the various special cases considered is the
identification of those models which exhibit an unbroken R-symmetry. One such
example corresponds to a non-linearly realized gauge symmetry where the chiral
field R-weight is required to vanish.Comment: 26 pages, LaTe
On Local Dilatation Invariance
The relationship between local Weyl scaling invariant models and local
dilatation invariant actions is critically scrutinized. While actions invariant
under local Weyl scalings can be constructed in a straightforward manner,
actions invariant under local dilatation transformations can only be achieved
in a very restrictive case. The invariant couplings of matter fields to an
Abelian vector field carrying a non-trivial scaling weight can be easily built,
but an invariant Abelian vector kinetic term can only be realized when the
local scale symmetry is spontaneously broken.Comment: 3 page
Supersymmetric multi-Higgs doublet model with non-linear electroweak symmetry breaking
The electroweak symmetry is nonlinearly realized in an extension of the
minimal supersymmetric standard model (MSSM) through an additional pair of
constrained Higgs doublet superfields. The superpotential couplings of this
constrained Higgs doublet pair to the MSSM Higgs doublet pair catalyze their
vacuum expectation values. The Higgs and Higgsino-gaugino mass spectrum is
presented for several choices of supersymmetry (SUSY) breaking and Higgs
superpotential mass parameters. The additional vacuum expectation values
provided by the constrained fields can produce a phenomenology quite different
than that of the MSSM .Comment: 41 pages, 16 figure
Twisted Boundary Conditions and Matching to the Effective Four Dimensional Theory
Nontrivial twisted boundary conditions associated with extra compact
dimensions produce an ambiguity in the value of the four dimensional coupling
constants of the renormalizable interactions of the twisted fields' zero modes.
Resolving this indeterminancy would require a knowledge of the exact form of
the higher dimensional action including the coefficients of higher dimensional
operators. For the case of moderately sized extra dimensions, the uncertainty
in the coupling constants can be of order one and may lead to modifications in
the stability of the model.Comment: 8 pages, REVTe
Global Capital Flows and Financing Constraints
Firms often cite financing constraints as one of their primary obstacles to investment. Global capital flows, by bringing in scarce capital, may ease host-country firms' financing constraints. However, if incoming foreign investors borrow heavily from domestic basnks, direct foreign investment (DFI) may exacerbate financing constraints by crowding host country firms out of domestic capital markets. Combininb a unique cross-country firm-level panel with time-series data on restrictions on international transactions and capital flows, we find that different measures of global flows are associated with a reduction in firm-level financing constraints. First, we show that one type of capital inflow--DFI--is associated with a reduction in financing constraints. Second, we test whether restrictions on international transactions affect firms' financing constraints. Our results suggest that only one type of restriction--those on capital account transactions--negatively affect firms' financing constraints. We also show that multinational firms are not financially constrained and do not appear to be sensitive to the level of DFI. This implies that DFI eases financing constraints for non-multinational firms. Finally, we show that DFI only eases financing constraints in the non-G7 countries.
Global capital flows and financing constraints
Firms often cite financing constraints as one of their primary obstacles to investment. Global capital flows, by bringing in scarce capital, may ease the financing constraints of host country firms. But if incoming foreign investors borrow heavily from domestic banks, foreign direct investment may exacerbate financing constraints by crowding host country firms out of domestic capital markets. Combining a unique cross-country firm-level panel with time-series data on restrictions on international transactions and capital flows, Harrison, Love, and McMillan find that different measures of global flows are associated with a reduction in firm-level financing constraints. First, the authors show that one type of capital inflow-foreign direct investment-is associated with a reduction in financing constraints. Second, they test whether restrictions on international transactions affects the financing constraints of firms. The results suggest that only one type of restriction-those on capital account transactions-negatively affects firms'financing constraints. The authors also show that multinational firms are not financially constrained and do not appear to be sensitive to the level of foreign directinvestment. This implies that foreign direct investment eases financing constraints for non-multinational firms. Finally, the authors show that (1) foreign direct investment only eases financing constraints in the non-G7 countries, and (2) other kinds of flows, such as portfolio investment, have no impact on financing constraints.International Terrorism&Counterterrorism,Payment Systems&Infrastructure,Financial Intermediation,Economic Theory&Research,Fiscal&Monetary Policy,Economic Theory&Research,International Terrorism&Counterterrorism,Financial Intermediation,Environmental Economics&Policies,Banks&Banking Reform
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