We investigate helicity amplitudes (HAs) of A→BC-type decays for arbitrary spin towards the kinematic endpoint. show that HAs are proportional to product Clebsch-Gordan coefficients (CGC) and velocity a non-negative power. The latter can be zero in which case HA is non-vanishing at At endpoint explicit breaking rotational symmetry, through external momenta, restored findings interpreted as spec...

Affine gravity is a connection-based formulation of that does not involve metric. After review basic properties affine gravity, we compute the tree-level scattering amplitude scalar particles interacting gravitationally via connection in curved spacetime. We find that, while classically equivalent to general relativity, differs from metric quantum gravity.

We present a coordinate space version of the factorization formula for connected tree part chronological products. consider general framework, and then we apply it QCD case.

Celestial amplitudes which use conformal primary wave functions rather than plane waves as external states offer a novel opportunity to study properties of with manifest covariance and give insight into potential holographic celestial field theory at the null boundary asymptotically flat space. Since translation invariance is obscured in basis, features that heavily rely on it appear be lost. A...