Marginality from Leading Soft Gluons

Abstract: Marginal operators in a $d$-dimensional conformal field theory (CFT), those with conformal dimension $\Delta=d$, give us information about the space of related theories. This can be incredibly useful when trying to develop an intrinsic definition of a holographic CFT. Recent work has established that in the case of celestial CFTs, those dual to asymptotically flat spacetimes, marginal operators can be constructed as shadow transforms of soft scalars. In this work, rather than starting from a bulk theory of scalars, we start with Yang-Mills and construct marginal operators from soft gluons via light transforms and a new set of transformations called half-shadow transforms. We obtain the local metric and connections for the associated conformal manifold by studying the two- and three-point functions of these marginal operators. We then discuss the implications of this for broadening our understanding of operator product expansions of soft operators in celestial CFTs.