A new approach to the multichannel scattering theory

1967 ◽  
Vol 48 (3) ◽  
pp. 721-734
Author(s):  
S. Sato
1980 ◽  
Vol 87 ◽  
pp. 583-587 ◽  
Author(s):  
R. N. Dixon ◽  
D. Field

The results of a new approach to the problem of the collisional step in the pumping cycle for OH and CH masers are reported. Rotationally inelastic collisions of OH and CH with both open and closed shell collision partners are considered using an expression derived from scattering theory. It is shown how Λ-doublet population inversion may arise in OH and CH. H-atoms and H2 may show opposite behaviour with CH, one partner cooling where collisions with the other lead to inversion. Implications for maser action are discussed and reveal excellent qualitative agreement with observation. Λ-doublet population inversion in OD, CD and NH+ is also considered.


1981 ◽  
Vol 36 (12) ◽  
pp. 1261-1275
Author(s):  
M. Sawicki ◽  
D. Schütte

Abstract The multichannel scattering theory is applied to the (2,2) sector of the (non-static) Lee model. Rigorous expressions for the transition amplitudes for two-fragments channels are derived. These expressions contain all effects of off-shell renormalization in a complete and consistent way. With suitable identification of the elementary fields of the model the reactions considered correspond to a simplified description of elastic proton-proton and pion-deuteron scattering and to pion absorption on the deuteron. We obtain a two-body equation for the description of the elastic proton-proton scattering and an extension of the two-potential formula for the pion-deuteron scattering, which can be cast into the form of the multiple-scattering series.


1968 ◽  
Vol 23 (11) ◽  
pp. 1834-1840
Author(s):  
Peter Natusch

In W. Sandhas’ field theoretical formulation1 of the nonrelativistic multichannel scattering theory the existence of asymptotic multiparticle field operators is discussed for phenomenological potentials. For potentials with momentum-dependent terms it is necessary to treat the convergence of time-dependent field operators on a special subset, — dense in the Hilbert space of states; concerning the position-dependency of tensor- and angular momentum-forces it is necessary to make use of a sharpened asymptotic condition.


1975 ◽  
Vol 34 (14) ◽  
pp. 849-852 ◽  
Author(s):  
John R. Laing ◽  
Karl F. Freed

1995 ◽  
Vol 18 (2-4) ◽  
pp. 213-227 ◽  
Author(s):  
Gy. Bencze ◽  
C. Chandler ◽  
A.G. Gibson ◽  
G.W. Pletsch

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