1166257
Peripheral reactions induced by a 2.1-GeV/nucleon 12C beam on a C target using a simple combinatorial model.
Recently acquired data on peripheral reactions induced by a /sup 12/C beam at 2.1 GeV/nucleon on a C target have been used to create a distribution of exclusive yields (''mass patterns'') in which the charge of detected fragments is ignored and the data supplemented by (presumed) missing nucleons. A simple multinomial expression using probabilities obtained from inclusive mass yields gives a satisfactory account of the revised data.
120543018
Evidence for Recoil Effects in Heavy-Ion Transfer Reactions
Data are prsented for single-proton transfer reactions induced by /sup 12/C and /sup 16/O ions on /sup 208/Pb at high bombarding energies. Analysis using a no-recoil distorted-wave Born approximation (DWBA) yields spectroscopic factors in marked disagreement with light-ion results. Analysis using DWBA theory including first-order recoil corrections indicates that the discrepancies are largely, if not entirely, the result of ignoring recoil effects. (auth)
37326897
Momentum distribution of projectile fragments and nuclear shape.
When one or two neutrons are lost in a collision between a projectile with a diffuse neutron-rich surface and a target nucleus, the transverse momentum distribution of the fragments thus produced can be fit with a double Gaussian curve in which a narrow component is superimposed on a much broader one. It is shown that this phenomenon is also observed for fragments from the normal'' projectile [sup 12]C. A density-dependent nucleon Fermi momentum and fragment recoil with the momentum of the lost nucleon give good agreement with experiment. The two Gaussian components do not require the presence near the nuclear surface of nucleons with two widely different binding energies, as often supposed.
120263133
Explanation of difference in one-neutron knock-out cross-sections between odd-odd and even-even projectiles with equal neutron and proton numbers
55099896
Double Gaussian Momentum Distribution of Projectile Fragments
120583015
Formation of projectile fragments by statistical decay in high-energy heavy-ion reactions
Abstract Cross sections for the removal of 1–4 nucleons from projectiles between 12 C and 56 Fe in collision with a hydrogen target are calculated and compared with experimental values. The calculation assumes that fragments are formed as a result of nucleon-nucleon collisions followed by sequential decay.
10069365
58Ni+n transmission, differential elastic scattering, and capture measurements and analysis up to 813 keV.
High-resolution neutron cross section measurements for $^{58}\mathrm{enriched}$ targets were made at the Oak Ridge Electron Linear Accelerator of transmission below 20 MeV, of differential elastic scattering from 10 keV to 5 MeV, and of capture from 2.6 keV to 2.5 MeV. The transmission data were analyzed from 0.1 to 813 keV with a multilevel R-matrix code which uses Bayes' theorem for the fitting process. This code provides energies and neutron widths of resonances within the analyzed region, as well as a possible parametrization for resonances external to that region, as a way of describing the smooth cross section over the entire energy range. The differential elastic data at different scattering angles were compared to theoretical calculations from 30 to 813 keV using an R-function code which is based on the Blatt-Biedenharn formalism. Various combinations of spin and parity were tested to predict cross sections for the well-defined lg0 resonances, and comparison with the data then provided spin and parity assignments for most of these resonances.
206324920
New measurement of the charge radius of the neutron.
The neutron transmission through a thorogenic liquid {sup 208}Pb sample 2 in. thick has been measured in the neutron energy range between 0.1 and 360 eV at the ORNL neutron source ORELA. Analyzing the shape of the transmission spectra as a function of neutron energy, agreement was found with the predictions by the atomic form factor. With a sensitivity for the mean squared charge radius of the neutron {l_angle}{ital r}{sup 2}{sub {ital n}}{r_angle} as high as 3%, a very reliable and also accurate result of {l_angle}{ital r}{sup 2}{sub {ital n}}{r_angle}={minus}0.113{plus_minus}0.003{plus_minus}0.004 fm{sup 2} was extracted. For the neutron-electron scattering length we obtained {ital b}{sub {ital ne}}=({minus}1.31{plus_minus}0.03{plus_minus}0.04){times}10{sup {minus}3} fm.
8196433
Reducing S duality to T duality.
The infrared limit of D = 4, N = 4 Yang-Mills theory with compact gauge group G compactified on a two-torus is governed by an effective superconformal field theory. We conjecture that this is a certain orbifold involving the maximal torus of G. Yang-Mills S-duality makes predictions for all correlators of this effective conformal field theory. These predictions are shown to be implied by the standard T-duality of the conformal field theory. Consequently, Montonen-Olive duality between electric and magnetic states reduces to the standard two-dimensional duality between momentum and winding states.
42736184
Nonrenormalization of the superstring tension.
It is argued that the superstring tension is not renormalized in perturbation theory for vacua which preserve N= 1 spacetime supersymmetry. Some implications of this result for macroscopic superstrings are discussed, as well as some analogies between macroscopic superstrings and solitons in supersymmetric theories.
26193328
Effects of neutron-star superconductivity on magnetic monopoles and core field decay.
From the magnetic properties of old neutron stars we propose that an observation of a sufficiently old pulsar limits any ``grand unified theory'' heavy magnetic monopole flux in the pulsar neighborhood to below 5\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}24}$${\ensuremath{\tau}}_{10}$${}^{\mathrm{\ensuremath{-}}2}$${\mathrm{cm}}^{\mathrm{\ensuremath{-}}}$ $^{2}$${\mathrm{sr}}^{\mathrm{\ensuremath{-}}1}$sec$^{\mathrm{\ensuremath{-}}1}$, where ${\ensuremath{\tau}}_{10}$ is the age (in ${10}^{10}$ yr) of the pulsar's present magnetic field and monopole speeds are \ensuremath{\sim}${10}^{\mathrm{\ensuremath{-}}3}$ c. For the millisecond pulsar PSR 1937+214 a major improvement over the Parker limit is obtained, which is also better than various limits from monopole catalysis of baryon decay, provided ${\ensuremath{\tau}}_{10}$\ensuremath{\gtrsim}${10}^{\mathrm{\ensuremath{-}}1}$. The consideration of monopole dynamics inside superconducting neutron-star cores leads to this conclusion.