3,546 research outputs found
On the holomorphic factorization for superconformal fields
For a generic value of the central charge, we prove the holomorphic
factorization of partition functions for free superconformal fields which are
defined on a compact Riemann surface without boundary. The partition functions
are viewed as functionals of the Beltrami coefficients and their fermionic
partners which variables parametrize superconformal classes of metrics.Comment: 5 pages, LATEX, MPI-Ph/92-7
Effect of Lessee\u27s Covenant to Leave Improvements on the Doctrine of Trade Fixtures
Although the common law rules regarding ownership and removability of trade fixtures are too well known and too often employed to necessitate comment, the application of these rules has caused some courts substantial difficulty in cases where the lease in question contains a covenant by the lessee during the term to become the property of the lessor. The Supreme Court of Washington has considered leases containing this type of clause in two cases involving contests between landlords and tenants over the ownership of chattels installed on the premises by the tenant and has laid down the rule that when such a covenant is used the law of trade fixtures is not applicable. This holding is very similar to, and has the same effect as earlier, decisions in other jurisdictions dealing with the same problem, but the Washington holding is not in line with the more modern decisions in the same jurisdictions, nor does it accord with the majority view
An example of resonance saturation at one loop
We argue that the large-Nc expansion of QCD can be used to treat a Lagrangian
of resonances in a perturbative way. As an illustration of this we compute the
L_10 coupling of the Chiral Lagrangian by integrating out resonance fields at
one loop. Given a Lagrangian and a renormalization scheme, this is how in
principle one can answer in a concrete and unambiguous manner questions such as
at what scale resonance saturation takes place.Comment: 9 pages, 5 figures. Enlarged discussion, results unchanged. To be
published in Phys. Rev.
Non-renormalization of the full <VVA> correlator at two-loop order
By explicit calculation of the two-loop QCD corrections we show that for
singlet axial and vector currents the full off-shell correlation function
in the limit of massless fermions is proportional to the one-loop result, when
calculated in the MS-bar scheme. By the same finite renormalization which is
needed to make the one-loop anomaly exact to all orders, we arrive at the
conclusion that two-loop corrections are absent altogether, for the complete
correlator not only its anomalous part. In accordance with the one-loop nature
of the correlator, one possible amplitude, which seems to be missing by
accident at the one-loop level, also does not show up at the two-loop level.Comment: 6 pages, 1 figur
Thin-disk laser pump schemes for large number of passes and moderate pump source quality
Novel thin-disk laser pump layouts are proposed yielding an increased number
of passes for a given pump module size and pump source quality. These novel
layouts result from a general scheme which bases on merging two simpler pump
optics arrangements. Some peculiar examples can be realized by adapting
standard commercially available pump optics simply by intro ducing an
additional mirror-pair. More pump passes yield better efficiency, opening the
way for usage of active materials with low absorption. In a standard multi-pass
pump design, scaling of the number of beam passes brings ab out an increase of
the overall size of the optical arrangement or an increase of the pump source
quality requirements. Such increases are minimized in our scheme, making them
eligible for industrial applicationsComment: 16 pages, 9 figure
Contributions of order to form factors and unitarity of the CKM matrix
The form factors for the semileptonic decay are computed to
order in generalized chiral perturbation theory. The main difference
with the standard expressions consists in contributions quadratic in
quark masses, which are described by a single divergence-free low-energy
constant, . A new simultaneous analysis is presented for the CKM matrix
element , the ratio , decay rates and the
scalar form factor slope . This framework easily accommodates the
precise value for deduced from superallowed nuclear -decays
Performance of Geant4 in simulating semiconductor particle detector response in the energy range below 1 MeV
Geant4 simulations play a crucial role in the analysis and interpretation of
experiments providing low energy precision tests of the Standard Model. This
paper focuses on the accuracy of the description of the electron processes in
the energy range between 100 and 1000 keV. The effect of the different
simulation parameters and multiple scattering models on the backscattering
coefficients is investigated. Simulations of the response of HPGe and
passivated implanted planar Si detectors to \beta{} particles are compared to
experimental results. An overall good agreement is found between Geant4
simulations and experimental data
Orbital-selective Mott transitions in the anisotropic two-band Hubbard model at finite temperatures
The anisotropic degenerate two-orbital Hubbard model is studied within
dynamical mean-field theory at low temperatures. High-precision calculations on
the basis of a refined quantum Monte Carlo (QMC) method reveal that two
distinct orbital-selective Mott transitions occur for a bandwidth ratio of 2
even in the absence of spin-flip contributions to the Hund exchange. The second
transition -- not seen in earlier studies using QMC, iterative perturbation
theory, and exact diagonalization -- is clearly exposed in a low-frequency
analysis of the self-energy and in local spectra.Comment: 4 pages, 5 figure
Hadronic Contributions to the Muon Anomaly in the Constituent Chiral Quark Model
The hadronic contributions to the anomalous magnetic moment of the muon which
are relevant for the confrontation between theory and experiment at the present
level of accuracy, are evaluated within the same framework: the constituent
chiral quark model. This includes the contributions from the dominant hadronic
vacuum polarization as well as from the next--to--leading order hadronic vacuum
polarization, the contributions from the hadronic light-by-light scattering,
and the contributions from the electroweak hadronic vertex.
They are all evaluated as a function of only one free parameter: the
constituent quark mass. We also comment on the comparison between our results
and other phenomenological evaluations.Comment: Several misprints corrected and a clarifying sentence added. Three
figures superposed and two references added. Version to appear in JHE
- …