PHENOMENOLOGICAL ANALYSIS OF SINGLE-PION PHOTOPRODUCTION

被引:432
作者
WALKER, RL
机构
[1] California Institute of Technology, Pasadena
来源
PHYSICAL REVIEW | 1969年 / 182卷 / 05期
关键词
D O I
10.1103/PhysRev.182.1729
中图分类号
O4 [物理学];
学科分类号
0702 ;
摘要
A phenomenological fit of the data on single-pion photoproduction is presented for laboratory photon energies up to 1.2 BeV. The analysis is made in terms of a simple model in which the photoproduction amplitude consists of three separate contributions: (1) the Born approximation with electric coupling only; (2) Breit-Wigner resonances for which the positions and widths are taken from pion-nucleon scattering data, but whose amplitudes are adjustable parameters; and (3) additional contributions in the low partial waves having J=12, 32, and52. A criterion for success of the model is that these added terms, which are the principal adjustable parameters, should vary smoothly with energy. Most of the resonances found in the phase-shift analysis of pion-nucleon scattering are included in the fit. In particular, there is reasonably good evidence in the photoproduction data for a broad S-wave resonance near 1560 MeV. The analysis is carried out in terms of the helicity-amplitude formalism, which is more convenient for this purpose than the conventional representation in terms of multipole amplitudes. © 1969 The American Physical Society.
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页码:1729 / +
页数:1
相关论文
共 111 条
[31]   PHOTOPRODUCTION OF PI+ AT O0 AND FORWARD ANGLES BETWEEN EGAMMA = 300 AND EGAMMA = 600 MEV [J].
BIZOT, JC ;
PEREZ, JP ;
TREILLE, D .
PHYSICS LETTERS B, 1967, B 25 (07) :489-&
[32]  
BLOOM E, 1967, THESIS CALIFORNIA I
[33]   RECOIL-PROTON POLARIZATION IN PIO PHOTOPRODUCTION [J].
BLOOM, ED ;
HEUSCH, CA ;
PRESCOTT, CY ;
ROCHESTER, LS .
PHYSICAL REVIEW LETTERS, 1967, 19 (11) :671-+
[34]   SINGLE PHOTOPRODUCTION OF NEUTRAL PI-MESONS ON HYDROGEN AT SMALL ANGLES BETWEEN 4 AND 5.8 GEV [J].
BRAUNSCHWEIG, M ;
BRAUNSCHWEIG, W ;
HUSMANN, D ;
LUBELSMEYER, K ;
SCHMITZ, D .
PHYSICS LETTERS B, 1968, B 26 (06) :405-+
[35]   SINGLE PHOTOPRODUCTION OF NEUTRAL PI-MESONS ON HYDROGEN AT SMALL ANGLES BETWEEN 1.3 AND 3 GEV [J].
BRAUNSCHWEIG, M ;
HUSMANN, D ;
LUBELSMEYER, K ;
SCHMITZ, D .
PHYSICS LETTERS, 1966, 22 (05) :705-+
[36]   ANALYSIS OF PION PHOTOPRODUCTION IN SECOND RESONANCE REGION [J].
CHAU, YC ;
DOMBEY, N ;
MOORHOUSE, RG .
PHYSICAL REVIEW, 1967, 163 (05) :1632-+
[37]   RELATIVISTIC DISPERSION RELATION APPROACH TO PHOTOMESON PRODUCTION [J].
CHEW, GF ;
GOLDBERGER, ML ;
LOW, FE ;
NAMBU, Y .
PHYSICAL REVIEW, 1957, 106 (06) :1345-1355
[38]  
Clinesmith Carl R, 1967, THESIS CALIFORNIA I
[39]  
CLINESMITH CR, 1966, P INT S ELECTRON PHO, V2, P245
[40]  
CLINESMITH CR, 1967, THESIS CAL I TECHN