Dripto Biswas (Turin U.),The DDF Reggeon and hidden Mandelstam maps
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Europe/Stockholm
Description
The study of massive string scattering amplitudes have recently gained renewed interest, partially because of their possible applications to the study of black hole scattering processes motivated by their correspondence with black hole microstates (a proposal due to Horowitz, Polchinski '97). I shall start by briefly introducing the DDF approach (due to Di Vechhia, Del Giudice and Fubini) for describing massive string states and compare with the usual covariant and lightcone approaches. In the process, I will also introduce the recently proposed Framed DDF approach which provides a geometric generalisation in terms of local frames.
In the second part of the talk, I will describe the Sciuto-Della Selva-Saito approach (1970) for the construction of the covariant N-Reggeon and show a similar approach for obtaining the DDF N-Reggeon. We shall also look at some recent results involving 'chaos' in the scattering of highly excited string states. Finally, in the third part of the talk, I will show in some detail, the appearance of Mandelstam maps, which relate the DDF amplitudes on the upper half-plane to the lightcone amplitudes described by Mandelstam diagrams (which are conformal to an upper half-plane with cuts).
