摘要:

The expected magnitudes of the leading relativistic effects on an off‐energy‐shellTmatrix element are estimated using the Bakamjian‐Thomas formulation of relativistic potential theory. For pion‐nucleon scattering at medium energy, the two largest corrections are expected to result from the use of relativistic relative momenta rather than nonrelativistic values. The importance of additional terms depends upon the detailed behavior of theTmatrix.

ISSN:0094-243X    

DOI:10.1063/1.30974

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

It is argued that introduction of the isobar degree of freedom in describing pion‐nucleus interactions provides a convenient, unified framework within which to discuss both many‐body corrections to the standard multiple scattering approach and the properties of the &Dgr; (1232) in nuclear matter. Important aspects of isobar‐nucleus dynamics, namely, isobar‐hole interactions and &Dgr; self‐energy modifications, are discussed in the context of pion elastic scattering and incoherent pion production.

ISSN:0094-243X    

DOI:10.1063/1.30821

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

Field theoretic aspects of pion nucleus physics are illustrated with a discussion of a phenomenological form of the pion‐nucleon off‐shell scattering amplitude and with comments on multiple scattering.

ISSN:0094-243X    

DOI:10.1063/1.30822

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

Recent theoretical studies (N&Dgr;), (NN*) and (&Dgr;&Dgr;) isobar admixtures to the two‐nucleon bound and conbinuum states are reviewed, including a critical survey of spectator experiments designed to search for the &Dgr; (1236) in the deuteron ground state.

ISSN:0094-243X    

DOI:10.1063/1.30824

出版商:AIP    

年代:1976

数据来源: AIP

ISSN:0094-243X    

DOI:10.1063/1.30825

出版商:AIP    

年代:1976

数据来源: AIP

ISSN:0094-243X    

DOI:10.1063/1.30826

出版商:AIP    

年代:1976

数据来源: AIP

ISSN:0094-243X    

DOI:10.1063/1.30827

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

The effect of the pion exchange current due to the Born term in the photoproduction amplitude on the charge form factors and distributions of4He,16O and40Ca is calculated in the simple harmonic oscillator shell model. The exchange current contribution is most notable in the case of the &agr;‐particle while it is rather unimportant in16O and40Ca. The contribution to the nuclear mean square radius is small (?0.03 fm2) and roughly independent of the mass number.

ISSN:0094-243X    

DOI:10.1063/1.30828

出版商:AIP    

年代:1976

数据来源: AIP

ISSN:0094-243X    

DOI:10.1063/1.30829

出版商:AIP    

年代:1976

数据来源: AIP

ISSN:0094-243X    

DOI:10.1063/1.30830

出版商:AIP    

年代:1976

数据来源: AIP