Theory HEP Seminar

Celestial Conformal Colliders

Sabrina Pasterski

Perimeter Institute

The goal is to have fun with the extrapolate dictionary in flat space holography. Here, massless scattering states are prepared by inserting operators at future and past null infinity and there are complementary position and boost eigenstate alternatives to the momentum space description. These go by the name Carrollian and Celestial CFT, respectively.

To tie into recent studies of enhanced asymptotic symmetry algebras, and discrete scattering bases, we can proceed as follows. We start by observing that the light-ray operators featured in the conformal collider literature are celestial primaries. This allows us to rephrase the corresponding 4D CFT correlators as probing a conformally soft matter sector of the 2D celestial CFT (CCFT). The recent w_{1+∞} symmetry observed in CCFT then suggests a natural extension of the conformal collider operators. Meanwhile, a symmetry informed correction to the hard and soft splitting for the BMS subalgebra automatically incorporates IR divergent loop corrections to the celestial stress tensor.

Two underlying themes of the talk will be 1. the utility of connecting position and momentum space descriptions, and 2. flat limits can be different (and fun!)