Three-point energy correlators and the celestial block expansion

Understand

We study the three-point energy correlator (EEEC), defined as a matrix element of a product of three energy detectors at different locations on the celestial sphere.

• Lorentz symmetry implies that the EEEC can be decomposed into special functions called celestial blocks.
• We compute three-point celestial blocks in an expansion around the collinear limit, where the three detectors approach each other on the celestial sphere.
• The leading term is a traditional $d{-}2$-dimensional four-point conformal block, and thus the collinear EEEC behaves like a conformally-invariant four-point function in $d{-}2$ dimensions.