1,741 research outputs found
Nonlinearly Realized Extended Supergravity
We provide nonlinear realization of supergravity with an arbitrary number of
supersymmetries by means of coset construction. The number of gravitino degrees
of freedom counts the number of supersymmetries, which will be possibly probed
in future experiments. We also consider goldstino embedding in the construction
to discuss the relation to nonlinear realization with rigid supersymmetries.Comment: 19 page
Strongly Coupled Semi-Direct Mediation of Supersymmetry Breaking
Strongly coupled semi-direct gauge mediation models of supersymmetry breaking
through massive mediators with standard model charges are investigated by means
of composite degrees of freedom. Sizable mediation is realized to generate the
standard model gaugino masses for a small mediator mass without breaking the
standard model symmetries.Comment: 7 pages; v2: the model generalized, gaugino mass corrected; v3:
explanations expanded, references adde
Anomalous quasiparticle transport in the superconducting state of CeCoIn5
We report on a study of thermal Hall conductivity k_xy in the superconducting
state of CeCoIn_5. The scaling relation and the density of states of the
delocalized quasiparticles, both obtained from k_xy, are consistent with d-wave
superconducting symmetry. The onset of superconductivity is accompanied by a
steep increase in the thermal Hall angle, pointing to a striking enhancement in
the quasiparticle mean free path. This enhancement is drastically suppressed in
a very weak magnetic field. These results highlight that CeCoIn_5 is unique
among superconductors. A small Fermi energy, a large superconducting gap, a
short coherence length, and a long mean free path all indicate that CeCoIn_5 is
clearly in the superclean regime (E_F/Delta<<l/xi), in which peculiar vortex
state is expected.Comment: 5 pages, 5 figure
Minimal Supergravity, Inflation, and All That
We consider an inflationary model in the hidden-sector broken supergravity
with an effectively large cutoff. The inflaton decay into right-handed
neutrinos naturally causes the observed baryon asymmetry of the universe with a
reheating temperature low enough to avoid the gravitino overproduction. We
emphasize that all the phenomenological requirements from cosmology and
particle physics are satisfied in the large-cutoff theory.Comment: 15pages, 4figures, text and refs. adde
Superconducting Gap Function in Antiferromagnetic Heavy-Fermion UPd_2Al_3 Probed by Angle Resolved Magnetothermal Transport Measurements
The superconducting gap structure of heavy fermion UPd_2Al_3, in which
unconventional superconductivity coexists with antiferromagnetic (AF) order
with atomic size local moments, was investigated by the thermal conductivity
measurements in a magnetic field rotating in various directions relative to the
crystal axes. The results provide strong evidence that the gap function
\Delta(k) has a single line node orthogonal to the c-axis located at the AF
Brillouin zone boundary, while \Delta(k) is isotropic within the basal plane.
The determined nodal structure is compatible with the resonance peak in the
dynamical susceptibility observed in neutron inelastic scattering experiments.
Based on these results, we conclude that the superconducting pairing function
of UPd_2Al_3 is most likely to be d-wave with a form \Delta(k)=\Delta_0
cos(k_zc)Comment: 10 pages, 9 figure
The Polonyi Problem and Upper bound on Inflation Scale in Supergravity
We reconsider the Polonyi problem in gravity-mediation models for
supersymmetry (SUSY) breaking. It has been argued that there is no problem in
the dynamical SUSY breaking scenarios, since the Polonyi field acquires a
sufficiently large mass of the order of the dynamical SUSY-breaking scale
Lamada_{SUSY}. However, we find that a linear term of the Polonyi field in the
Kahler potential brings us back to the Polonyi problem, unless the inflation
scale is sufficiently low, H_{inf} < 10^{8} GeV, or the reheating temperature
is extremely low, T_{R} < 100 GeV. Here, this Polonyi problem is more serious
than the original one, since the Polonyi field mainly decays into a pair of
gravitinos.Comment: 17 pages, 1 figure, minor corrections, published versio
Gap Symmetry of Superconductivity in UPd2Al3
The angle dependent thermal conductivity of the heavy-fermion superconductor
UPdAl in the vortex state was recently measured by Watanabe et al. Here
we analyze this data from two perspectives: universal heat conduction and the
angle-dependence. We conclude that the superconducting gap function
in UPdAl has horizontal nodes and is given by
, with .Comment: 8 pages, 4 figures, improved figures in replacemen
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