Statut  Confirmé 
Série  SEMINFOR 
Domaines  hepth 
Date  Jeudi 12 Octobre 2017 
Heure  13:00 
Institut  LPTENS 
Salle  LPTENS library 
Nom de l'orateur  Maharana 
Prenom de l'orateur  Jnanadeva 
Addresse email de l'orateur  
Institution de l'orateur  Institute of Physics, Bhubaneswar, India 
Titre  Analyticities of Scattering Amplitudes 
Résumé  The properties of the high energy behavior of the scattering amplitude of massive, neutral and spinless particles in higher dimensional field theories are investigated. The axiomatic formulation of Lehmann, Symanzik and Zimmermann is adopted. The analyticity properties of the causal, the retarded and the advanced functions associated with the four point elastic amplitudes are studied. The analog of the LehmannJostDyson representation is obtained in higher dimensional field theories. The generalized JLD representation is utilized to derive the tplane analyticity property of the amplitude. The existence of an ellipse analogous to the Lehmann ellipse is demonstrated. Thus a fixedt dispersion relation can be written down with finite number of subtractions due to the temperedness of the amplitudes. The domain of analyticity of scattering amplitude in s and t variables is extended by imposing unitarity constraints. A generalized version of Martin's theorem is derived to prove the existence of such a domain in Ddimensional field theories. It is shown that the amplitude can be expanded in a power series in t which converges for t<R; R being sindependent. The positivity properties of absorptive amplitudes are derived to prove the tplane analyticity of amplitude. In the extended analyticity domain dispersion relations are written with two subtractions. The bound on the total cross section is derived from LSZ axioms without any extra ad hoc assumptions. 
Numéro de preprint arXiv  1608.06402 
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