62 research outputs found
An explanation of the ABC enhancement in the dd -> alpha X reaction at intermediate energies
The dd -> alpha X reaction is studied in a model where each pair of nucleons
in the projectile and target deuterons undergoes pion production through the NN
-> d pi reaction. The condition that the two deuterons fuse to form an
alpha-particle then leads to peaks at small missing masses, the well-known ABC
enhancement, but also a broad structure around the maximum missing mass. With a
simplified input amplitude the model gives a quantitative description of both
the alpha-particle momentum and angular distributions for a deuteron beam
energy of 1250 MeV.Comment: 10 pages, Latex2e, 1 eps figure, submitted to Phys. Lett.
Extended sudden approximation model for high-energy nucleon removal reactions
A model based on the sudden approximation has been developed to describe high
energy single nucleon removal reactions. Within this approach, which takes as
its starting point the formalism of Hansen \cite{Anne2}, the nucleon-removal
cross section and the full 3-dimensional momentum distributions of the core
fragments including absorption, diffraction, Coulomb and nuclear-Coulomb
interference amplitudes, have been calculated. The Coulomb breakup has been
treated to all orders for the dipole interaction. The model has been compared
to experimental data for a range of light, neutron-rich psd-shell nuclei. Good
agreement was found for both the inclusive cross sections and momentum
distributions. In the case of C, comparison is also made with the
results of calculations using the transfer-to-the-continuum model. The
calculated 3-dimensional momentum distributions exhibit longitudinal and
transverse momentum components that are strongly coupled by the reaction for
s-wave states, whilst no such effect is apparent for d-waves. Incomplete
detection of transverse momenta arising fromlimited experimental acceptances
thus leads to a narrowing of the longitudinal distributions for nuclei with
significant s-wave valence neutron configurations, as confirmed by the data.
Asymmetries in the longitudinal momentum distributions attributed to
diffractive dissociation are also explored.Comment: 16 figures, submitted to Phys. Rev.
Radiative Decay Width Measurements of Neutral Kaon Excitations Using the Primakoff Effect
We produce a sample consisting of 147 candidate events, with minimal
backgrounds, of the mixed axial vector pair K1(1270)-K1(1400) by exciting Kl's
in the Coulomb field of lead and report the first measurements of the radiative
widths Gamma_r(K1(1400)) = 280.8+-23.2(stat)+-40.4(syst) keV and
Gamma_r(K1(1270)) = 73.2+- 6.1(stat)+-28.3(syst) keV. We also place 90% CL
upper limits Gamma_r(K*(1410)) < 52.9 keV for the vector state and
Gamma_r(K2*(1430)) < 5.4 keV for the tensor state. These measurements allow for
significant tests of quark-model predictions of radiative widths for the
low-lying vector mesons.Comment: PRL-size article, 4 figure
A review of the optical properties of alloys and intermetallics for plasmonics
Alternative materials are required to enhance the efficacy of plasmonic
devices. We discuss the optical properties of a number of alloys, doped metals,
intermetallics, silicides, metallic glasses and high pressure materials. We
conclude that due to the probability of low frequency interband transitions,
materials with partially occupied d-states perform poorly as plasmonic
materials, ruling out many alloys, intermetallics and silicides as viable. The
increased probability of electron-electron and electron-phonon scattering rules
out many doped and glassy metals.Comment: 26 pages, 10 figures, 3 table
STRONG COUPLING EXPANSION OF LATTICE GAUGE-THEORIES AT FINITE TEMPERATURE
FALDT G, Petersson B. STRONG COUPLING EXPANSION OF LATTICE GAUGE-THEORIES AT FINITE TEMPERATURE. NUCLEAR PHYSICS B. 1986;265(1):197-222
DECAYS K-]PIGAMMAGAMMA AND K+-]PI+PIO IN ETA-POLE APPROXIMATION
FALDT G, Petersson B, PILKUHN H. DECAYS K-]PIGAMMAGAMMA AND K+-]PI+PIO IN ETA-POLE APPROXIMATION. Nuclear Physics B. 1967;3(3):234-240
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