scholarly journals The ??Decay of 8B, and 2+ States Of 8Be

1969 ◽  
Vol 22 (6) ◽  
pp. 663 ◽  
Author(s):  
GJ Clark ◽  
PB Treacy ◽  
SN Tucker
Keyword(s):  
Elastic Scattering ◽  
Energy Distribution ◽  
Matrix Formalism ◽  
R Matrix ◽  
Channel Radius

The {l-decay of 8B has been investigated by measuring the energy distribution of the <x-particles from subsequent breakup of 8Be. The data have been analysed, in conjunction with data from <X-o< elastic scattering, in a three-level R-matrix formalism. Consistent fits are obtained for a channel radius of 6�0�0�5 fm, and the existence of a broad 2+ state of 8Be near 12�0 MeV, of width 14 MeV, is confirmed.

scholarly journals Experimental Investigation and R-matrix Analysis of Low-lying Levels in 5He and 5Li

1988 ◽  
Vol 41 (4) ◽  
pp. 525 ◽  
Author(s):  
CL Woods ◽  
FC Barker ◽  
WN Catford ◽  
LK Fifield ◽  
NA Orr
Keyword(s):  
Matrix Analysis ◽  
Scattering Data ◽  
Matrix Formalism ◽  
Satisfactory Description ◽  
Model Calculations ◽  
R Matrix ◽  
Channel Radius ◽  
Direct Reactions ◽  
Method Of Production ◽  
Parameter Values

The ~cle-unstable nuclei SHe and Su have been studied via the 4He<,U,6U)SHe and 4He( Li,6He)SU stripping reactions at beam energies of 50 MeV and the 6U(12C, 13N)SHe and 6Li(13C, 14C)SU pickup reactions at 90 MeV. The experimental data clearly demonstrate a dependence of the lineshapes on the method of production of the mass-5 nuclei (in this case pickup or stripping). The observed lineshapes were analysed using the R-matrix formalism in a two-level approximation for each r value, with parameter values deduced from fits to the available 4He + nucleon scattering data. A best channel radius of 5�5 � 1� 0 fm was determined from the stripping data, and the corresponding set of R-matrix parameters also provided a satisfactory description of the pickup data. This channel radius is significantly larger than that employed in most previous analyses. Properties of the lowest ~ - and ! - sta~s of SHe and sU, observed via direct reactions, ate deduced from the parameter values. These properties are compared with results from earlier experimental analyses and the inferred properties of positive-parity states are compared with the results of recent shell-model calculations.

scholarly journals 0+ States of 8Be

1968 ◽  
Vol 21 (3) ◽  
pp. 239 ◽  
Author(s):  
FC Barker ◽  
HJ Hay ◽  
PB Treacy
Keyword(s):  
Excited State ◽  
Excited States ◽  
Cross Section ◽  
Scattering Data ◽  
Excitation Energies ◽  
R Matrix ◽  
Channel Radius

The light even nuclei with A ;;;. 10 have 0+ excited states near 6 MeV, probably with large (X-particle reduced widths. A similar state in BBe would be very broad. Evidence for 0+ excited states in BBe has been obtained here using many-level R-matrix fits to known (X-(X scattering data, but the excitation energies depend strongly on the assumed channel radius. For a simultaneous fit to the 9Be(p, d)BBe cross section, assuming these higher states are not strongly populated, the channel radius is restricted to (7~~) fm, implying a 0+ excited state at (6=f3) MeV of width (9=f4) MeV.

scholarly journals The Ghost Anomaly in the 9Be(p, d)8Be Reaction

1976 ◽  
Vol 29 (4) ◽  
pp. 245 ◽  
Author(s):  
FC Barker ◽  
GM Crawley ◽  
PS Miller ◽  
WF Steele
Keyword(s):  
Ground State ◽  
Matrix Formalism ◽  
R Matrix

The ghost of the 8Be ground state has been observed in the 9Be(p, d)8Be reaction, and fitted using a many-level R-matrix formalism.

Transfer Matrix of the Two-dimensional Ising Model

2020 ◽  
pp. 211-234
Author(s):  
Giuseppe Mussardo
Keyword(s):  
Ising Model ◽  
Critical Point ◽  
Transfer Matrix ◽  
Functional Equations ◽  
Baxter Equation ◽  
Matrix Formalism ◽  
Two Dimensional ◽  
R Matrix ◽  
Transfer Matrix Formalism ◽  
Lowest Eigenvalue

This chapter deals with the exact solution of the two-dimensional Ising model as it is achieved through the transfer matrix formalism. It discusses the crucial role played by the commutative properties of the transfer matrices, which lead to a functional equation for their eigenvalues. The exact free energy of the Ising model and its critical point can be identified by means of the lowest eigenvalue. The chapter covers Baxter's approach, the Yang–Baxter equation and its relation to the Boltzmann weights, the R-matrix, and discusses activity away from the critical point, the six-vertex model, as well as functional equations and symmetries.

Optisches Modell für die Streuung von K--Mesonen an Kernen

1957 ◽  
Vol 12 (12) ◽  
pp. 947-955 ◽  
Author(s):  
P. Mittelstaedt
Keyword(s):  
Angular Distribution ◽  
Elastic Scattering ◽  
Energy Distribution ◽  
Inelastic Scattering ◽  
Optical Potential ◽  
Optical Model ◽  
Experimental Results ◽  
The Real ◽  
Elastic And Inelastic Scattering ◽  
Plate Group

The elastic and inelastic scattering of K--Mesons by complex nuclei are described by means of a phenomenological optical model. The real and the imaginary parts of the optical potential are determined by a comparison with the experimental results of the Goettingen and of the Bern plate group from the angular distribution of the elastic scattering and also from the energy distribution of the inelastically scattered K--Mesons by means of the GoLDBERGER-method.

APPLICATION OF THE R-MATRIX METHOD TO CDCC CALCULATIONS

2010 ◽  
Vol 25 (21n23) ◽  
pp. 1745-1749 ◽  
Author(s):  
T. DRUET ◽  
D. BAYE ◽  
P. DESCOUVEMONT ◽  
J.-M. SPARENBERG
Keyword(s):  
Elastic Scattering ◽  
Matrix Method ◽  
R Matrix ◽  
Future Developments ◽  
Coupled Channel ◽  
The Continuum

The R-matrix method is applied to the Continuum Discretized Coupled Channel (CDCC) approximation. The variational basis is chosen as Lagrange functions, which are shown to be efficient and accurate. We apply the general formalism to the d + 58 Ni elastic scattering at Ed = 80 MeV . Future developments are briefly discussed.

Influences de l'énergie thermique et de la répartition d'énergie des électrons dans les mesures par impact électronique

1975 ◽  
Vol 53 (6) ◽  
pp. 628-636 ◽  
Author(s):  
A. Delage ◽  
D. Roy ◽  
J.-D. Carette
Keyword(s):  
Elastic Scattering ◽  
Energy Distribution ◽  
Electron Energy ◽  
Thermal Energy ◽  
Atoms And Molecules ◽  
Electronic Impact ◽  
Convenient Form ◽  
Impact Experiments

The influence of thermal energy of atoms and molecules and of the energy distribution of electrons on results obtained from electronic impact experiments are analyzed. Special attention is devoted to the width of the peaks found in the spectra of elastically and inelastically scattered electrons. Results are presented in the convenient form of tables, graphs, and a nomogram in order that they may be easily accessible to researchers in the field of electronic collisions. The method used to calculate the influences of the experimental factors has also been used in the case of resonant elastic scattering of electrons in helium. These experimental factors are the thermal energy of the particles of the target and the spread of the electron energy.

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