6,001 research outputs found
Electric dipole moments in supersymmetric theories
Intrinsic EDMs in microscopic systems at a level of sensitivity achievable in
experiments under way or foreseen are predicted in supersymmetric unified
theories. I describe this and other sources of measurable EDMs and I show how
these sources can be distinguished through experiments in different systems.Comment: 5 pages, LaTex2e using amstex.sty, amssymb.sty, apalike.sty, no
figs., to appear in Proceedings of the XXIV ITEP Winter School of Physic
Hadronic light-by-light scattering contribution to the muon g-2
We briefly review the current status of the hadronic light-by-light
scattering correction to the muon g-2. Then we present our semi-analytical
evaluation of the pion-pole contribution, using a description of the
pion-photon-photon form factor based on large-N_C and short-distance properties
of QCD. We also sketch an effective field theory approach to hadronic
light-by-light scattering. In view of several still unsolved problems, our
conservative estimate for the full hadronic light-by-light scattering
contribution is a_{mu}(LbyL;had) = + 8 (4) x 10^{-10}.Comment: 4 pages including 2 figures, Latex, uses espcrc2.sty; Talk presented
at the 9th International High-Energy Physics Conference in Quantum
Chromodynamics (QCD 2002), Montpellier, France, 2-9 July 200
Nucleon Electric Dipole Moments and the Isovector Parity- and Time-Reversal-Odd Pion-Nucleon Coupling
The isovector time-reversal- and parity-violating pion-nucleon coupling
is uniquely sensitive to dimension six interactions
between right-handed light quarks and the Standard Model Higgs doublet that
naturally arises in left-right symmetric models. Recent work has used the
-induced one-loop contribution to the neutron electric
dipole moment , together with the present experimental bound, to
constrain the CP-violating parameters of the left-right symmetric model. We
show that this and related analyses are based on an earlier meson theory
computation that is not consistent with the power-counting appropriate for an
effective field theory. We repeat the one-loop calculation using heavy baryon
chiral perturbation theory and find that the resulting sensitivity to
is suppressed, implying more relaxed constraints on the
parameter space of the left-right symmetric model. Assuming no cancellations
between this loop contribution and other contributions, such as the leading
order EDM low-energy constant, the present limit on implies
.Comment: 10 pages, 4 figure
Library of medium-resolution fiber optic echelle spectra of F, G, K, and M field dwarfs to giants stars
We present a library of Penn State Fiber Optic Echelle (FOE) observations of
a sample of field stars with spectral types F to M and luminosity classes V to
I. The spectral coverage is from 3800 AA to 10000 AA with nominal a resolving
power 12000. These spectra include many of the spectral lines most widely used
as optical and near-infrared indicators of chromospheric activity such as the
Balmer lines (H_alpha, H_beta), Ca II H & K, Mg I b triplet, Na I D_{1} and
D_{2}, He I D_{3}, and Ca II IRT lines. There are also a large number of
photospheric lines, which can also be affected by chromospheric activity, and
temperature sensitive photospheric features such as TiO bands. The spectra have
been compiled with the goal of providing a set of standards observed at medium
resolution. We have extensively used such data for the study of active
chromosphere stars by applying a spectral subtraction technique. However, the
data set presented here can also be utilized in a wide variety of ways ranging
from radial velocity templates to study of variable stars and stellar
population synthesis. This library can also be used for spectral classification
purposes and determination of atmospheric parameters (T_eff, log{g}, [Fe/H]). A
digital version of all the fully reduced spectra is available via ftp and the
World Wide Web (WWW) in FITS format.Comment: Latex file with 17 pages, 4 figures. Full postscript (text and
figures) available at http://www.ucm.es/info/Astrof/fgkmsl/FOEfgkmsl.html To
be published in ApJ
Hadronic Light-by-Light Contribution to Muon g-2: Status and Prospects
I review the recent calculations and present status of the hadronic
light-by-light contribution to the muon g-2.Comment: 8 pages, 1 figure. Invited talk at PHIPSI08, International Conference
on e+e- collisions from Phi to Psi, April 7-10 2008, Frascati, Italy. v2:
Wrong year in one referenc
Magnetization and EPR studies of the single molecule magnet Ni with integrated sensors
Integrated magnetic sensors that allow simultaneous EPR and magnetization
measurements have been developed to study single molecule magnets. A high
frequency microstrip resonator has been integrated with a micro-Hall effect
magnetometer. EPR spectroscopy is used to determine the energy splitting
between the low lying spin-states of a Ni single crystal, with an S=4
ground state, as a function of applied fields, both longitudinal and transverse
to the easy axis at 0.4 K. Concurrent magnetization measurements show changes
in spin-population associated with microwave absorption. Such studies enable
determination of the energy relaxation time of the spin system.Comment: 4 pages, 4 figures, accepted for publication (Proceedings of the 10th
Joint MMM/Intermag Conference, which will be published as special issues of
the Journal of Applied Physics
Algorithms and literate programs for weighted low-rank approximation with missing data
Linear models identification from data with missing values is posed as a weighted low-rank approximation problem with weights related to the missing values equal to zero. Alternating projections and variable projections methods for solving the resulting problem are outlined and implemented in a literate programming style, using Matlab/Octave's scripting language. The methods are evaluated on synthetic data and real data from the MovieLens data sets
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