Please note that the list below only shows forthcoming events, which may not include regular events that have not yet been entered for the forthcoming term. Please see the past events page for a list of all seminar series that the department has on offer.

 

Past events in this series


Wed, 16 Jul 2025
11:30
L5

Chiral fields for massive higher spins

Dr Alex Ochirov
(Shanghai Tech)
Abstract

I will review some recent developments in effective field theory of  composite higher-spin particles, namely, Zinoviev's massive gauge symmetry and 
the new chiral-field approach. The latter approach was inspired by a simple spinor-helicity structure first singled out by Arkani-Hamed, Huang and Huang, which encodes the higher-spin information of two massive particles. It turned out to be persistent in tree-level amplitudes with any number of additional identical-helicity gluons or gravitons, leading to the discovery of the chiral-field approach. I will mention the applications of massive higher-spin scattering amplitudes to classical gravitational dynamics of rotating black  holes. 
 

Wed, 16 Jul 2025
14:00
L5

Twistor-space gauge-theory amplitudes from off-shell functionals

Hiren Kakkad
(Shanghai Tech)
Abstract

I will present a pair of off-shell functionals in position space, localized on the self-dual and the anti-self-dual planes which naturally give the Parke-Taylor denominator. These can therefore be used: 
i) to compute scattering amplitudes of particles with different spins and helicities; and 
ii) develop a Lagrangian description. 
Using Witten's half-Fourier transform, I will express these functionals in twistor space and present the kernels in a closed compact form. For even multiplicities, I will show how to obtain this form geometrically which than then be “folded” to get the one-less odd-multiplicity result.