908 research outputs found
Option pricing and perfect hedging on correlated stocks
We develop a theory for option pricing with perfect hedging in an inefficient
market model where the underlying price variations are autocorrelated over a
time tau. This is accomplished by assuming that the underlying noise in the
system is derived by an Ornstein-Uhlenbeck, rather than from a Wiener process.
With a modified portfolio consisting in calls, secondary calls and bonds we
achieve a riskless strategy which results in a closed expression for the
European call price which is always lower than Black-Scholes price. We also
obtain a partial differential equation for the option price and study the
sensitivity to several parameters and the risk of the dynamics of the call
price.Comment: 36 pages, 8 figures, 2 table
Dynamic Spatial Autoregressive Models with Autoregressive and Heteroskedastic Disturbances
We propose a new class of models specifically tailored for spatio-temporal
data analysis. To this end, we generalize the spatial autoregressive model with
autoregressive and heteroskedastic disturbances, i.e. SARAR(1,1), by exploiting
the recent advancements in Score Driven (SD) models typically used in time
series econometrics. In particular, we allow for time-varying spatial
autoregressive coefficients as well as time-varying regressor coefficients and
cross-sectional standard deviations. We report an extensive Monte Carlo
simulation study in order to investigate the finite sample properties of the
Maximum Likelihood estimator for the new class of models as well as its
flexibility in explaining several dynamic spatial dependence processes. The new
proposed class of models are found to be economically preferred by rational
investors through an application in portfolio optimization.Comment: 33 pages, 5 figure
Inclusive Scattering of Polarized Electrons on Polarized 3He Effects of Final State Interaction and the Magnetic Form Factor of the Neutron
Effects of final state interaction on asymmetries in inclusive scattering of
polarized electrons on polarized 3He are investigated using consistent 3He
bound state wave function and 3N continuum scattering states. Significant
effects are found, which influence the extraction of the magnetic neutron form
factor from A_T'. The enhancement found experimentally for A_TL' near the 3N
breakup threshold, which could not be explained in calculations carried through
in plane wave impulse approximation up to now, occurs now also in theory if the
full final state interaction is included.Comment: 29 pages, 5 figure
Precise Neutron Magnetic Form Factors
Precise data on the neutron magnetic form factor G_{mn} have been obtained
with measurements of the ratio of cross sections of D(e,e'n) and D(e,e'p) up to
momentum transfers of Q^2 = 0.9 (GeV/c)^2. Data with typical uncertainties of
1.5% are presented. These data allow for the first time to extract a precise
value of the magnetic radius of the neutron.Comment: 10 pages, 2 figures, submitted to Physics Letters
A precise measurement of the deuteron elastic structure function A(Q^2)
The A(Q^2) structure function in elastic electron-deuteron scattering was
measured at six momentum transfers Q^2 between 0.66 and 1.80 (GeV/c)^2 in Hall
C at Jefferson Laboratory. The scattered electrons and recoil deuterons were
detected in coincidence, at a fixed deuteron angle of 60.5 degrees. These new
precise measurements resolve discrepancies between older sets of data. They put
significant constraints on existing models of the deuteron electromagnetic
structure, and on the strength of isoscalar meson exchange currents.Comment: 3 LaTeX pages plus 2 PS figure
Measurement of Tensor Polarization in Elastic Electron-Deuteron Scattering at Large Momentum Transfer
Tensor polarization observables (t20, t21 and t22) have been measured in
elastic electron-deuteron scattering for six values of momentum transfer
between 0.66 and 1.7 (GeV/c)^2. The experiment was performed at the Jefferson
Laboratory in Hall C using the electron HMS Spectrometer, a specially designed
deuteron magnetic channel and the recoil deuteron polarimeter POLDER. The new
data determine to much larger Q^2 the deuteron charge form factors G_C and G_Q.
They are in good agreement with relativistic calculations and disagree with
pQCD predictions.Comment: 5 pages, 4 figures, for associated informations, see
http://isnwww.in2p3.fr/hadrons/t20/t20_ang.html clarification about several
topics, one figure has been had, extraction of form factors use AQ
interpolation in our Q2 range onl
Nucleon Charge and Magnetization Densities from Sachs Form Factors
Relativistic prescriptions relating Sachs form factors to nucleon charge and
magnetization densities are used to fit recent data for both the proton and the
neutron. The analysis uses expansions in complete radial bases to minimize
model dependence and to estimate the uncertainties in radial densities due to
limitation of the range of momentum transfer. We find that the charge
distribution for the proton is significantly broad than its magnetization
density and that the magnetization density is slightly broader for the neutron
than the proton. The neutron charge form factor is consistent with the Galster
parametrization over the available range of Q^2, but relativistic inversion
produces a softer radial density. Discrete ambiguities in the inversion method
are analyzed in detail. The method of Mitra and Kumari ensures compatibility
with pQCD and is most useful for extrapolating form factors to large Q^2.Comment: To appear in Phys. Rev. C. Two new figures and accompanying text have
been added and several discussions have been clarified with no significant
changes to the conclusions. Now contains 47 pages including 21 figures and 2
table
Large Momentum Transfer Measurements of the Deuteron Elastic Structure Function A(Q^2) at Jefferson Laboratory
The deuteron elastic structure function A(Q^2) has been extracted in the Q^2
range 0.7 to 6.0 (GeV/c)^2 from cross section measurements of elastic
electron-deuteron scattering in coincidence using the Hall A Facility of
Jefferson Laboratory. The data are compared to theoretical models based on the
impulse approximation with inclusion of meson-exchange currents, and to
predictions of quark dimensional scaling and perturbative quantum
chromodynamicsComment: Submitted to Physical Review Letter
The ratio of proton's electric to magnetic form factors measured by polarization transfer
The ratio of the proton's elastic electromagnetic form factors was obtained
by measuring the transverse and longitudinal polarizations of recoiling protons
from the elastic scattering of polarized electrons with unpolarized protons.
The ratio of the electric to magnetic form factor is proportional to the ratio
of the transverse to longitudinal recoil polarizations. The ratio was measured
over a range of four-momentum transfer squared between 0.5 and 3.5 GeV-squared.
Simultaneous measurement of transverse and longitudinal polarizations in a
polarimeter provides good control of the systematic uncertainty. The results
for the ratio of the proton's electric to magnetic form factors show a
systematic decrease with increasing four momentum squared, indicating for the
first time a marked difference in the spatial distribution of charge and
magnetization currents in the proton.Comment: 5 pages, 2 figures, version of paper after corrections due to
referees comments and shortened by removing one figure for Physical Review
Letter
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