Modification of Fox-Wolfram Moments for Hadron Colliders

TL;DR

This paper introduces modified Fox-Wolfram moments for hadron colliders that are invariant under boosts and rotations, improving the separation of Higgs to b-quark signals from background.

Contribution

The paper proposes a new form of Fox-Wolfram moments tailored for hadron collider events, addressing boost invariance issues.

Findings

Modified moments are boost-invariant and rotation-invariant in the transverse plane.

Improved signal-background separation in Higgs to b-quarks analysis.

Demonstrated effectiveness in a realistic collider scenario.

Abstract

Collisions of composite particles impose an arbitrary boost in the longitudinal direction on a given event. This implies that the centre-of-mass frame at hadron colliders is undetermined for processes with missing energy in the final state. This motivates the modification of the Fox-Wolfram moments such that the moments for a given event are identical when viewed in the lab or centre-of-mass frame of the beam. The resulting moments are invariant under rotations in the plane transverse to the beam and boosts parallel to the beam. These moments are then used to demonstrate improved signal separation in the channel where the Higgs decays to two b-quarks while being produced in association with a vector boson.