摘要:

AbstractThe theoretical importance of experiments with polarised targets for pion photoproduction at high energies is discussed.In an introductory chapter the basic formulas and simple Regge pole models are introduced in connection with elastic pion‐proton scattering. The relevance of Regge‐cut models is considered in connection with pion‐charge‐exchange scattering. In the main part we write down formulas for the polarisation parameters in terms of the helicity amplitudes for pion photoproduction. Then we concentrate on the target asymmetryAfor photoproduction of neutral and charged pions. Several models with Regge poles and Regge cuts generated by absorption are presented and discussed concerning the results forA. In the last part we report a fit to π±photoproduction data and give predictions ofAfor γp → π+n

ISSN:0015-8208    

DOI:10.1002/prop.19710191102

出版商:WILEY‐VCH Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractA review of the methods of constructing the scattering amplitudes and Green functions in the non‐renormalizable quantum field theories with rapidly increasing spectral functions is given. Such theories as the theories with the chiral Lagrangians, those which describe the interactions with gravitational fields and the theories of weak interactions can be taken as examples. Three big groups of these methods are presented here. In particular, these are as follows: construction of the scattering amplitude inx‐space (the functionF(x)), construction of the scattering amplitude in momentum space (the functionF˜ (p)) and definition of the scattering amplitudes by solving the appropriate equations (inx‐ orp‐Space).This works was reported at the Second International Symposium on Non‐local Quantum Field Theory in 1970 at

ISSN:0015-8208    

DOI:10.1002/prop.19710191103

出版商:WILEY‐VCH Verlag    

年代:1971

数据来源: WILEY

摘要:

AbstractWe construct amplitudes which are represented by a Mandelstam representation with a finite number of subtractions and that satisfy ππ crossing symmetry and the unitarity constraints ImflI(s) ≧|flI(s)|2,l=0, 1, 2,…, for all energies above thresholds>4, in the three isospin channelsI=0, 1, 2.The following types of solutions are derived.1The amplitudes have a positive double spectral function ϱ(s, t) ≧ 0. The total cross section decreases like σT(s) ∼ (logs)‐δfor arbitrary δ ≧ 1, including the limiting case δ=1.2The amplitudes are dominated by Regge poles, the total cross section can reach a constant asymptotic value, σT(s) → const.3The amplitudes are dominated by Regge cuts, the total cross section can increase logarit

ISSN:0015-8208    

DOI:10.1002/prop.19710191104

出版商:WILEY‐VCH Verlag    

年代:1971

数据来源: WILEY

ISSN:0015-8208    

DOI:10.1002/prop.19710191101

出版商:WILEY‐VCH Verlag    

年代:1971

数据来源: WILEY