An upper limit on the scale of new physics phenomena from rising cross sections in high multiplicity Higgs and vector boson events

TL;DR

This paper investigates the energy scale at which high multiplicity Higgs and gauge boson events challenge the Standard Model, suggesting new physics or non-perturbative effects must emerge before this scale, estimated around 1000 TeV.

Contribution

It provides an upper limit on the energy scale for new physics based on high multiplicity processes and experimental constraints, highlighting the need for beyond Standard Model physics.

Findings

High multiplicity processes exceed experimental bounds above current energies.

Critical energy scale estimated around 1000 TeV based on Higgs mass.

New physics or non-perturbative effects are required before this scale.

Abstract

In very high energy scattering events production of multiple Higgs and electroweak gauge bosons becomes possible. Indeed the perturbative cross section for these processes grows with increasing energy, eventually violating perturbative unitarity. In addition to perturbative unitarity we also examine constraints on high multiplicity processes arising from experimentally measured quantities. These include the shape of the Z-peak and upper limits on scattering cross sections of cosmic rays. We find that the rate of high multiplicity electroweak processes will exceed these upper limits at energies not significantly above what can be currently tested experimentally. This leaves two options: 1) The electroweak sector becomes truly non-perturbative in this regime or 2) Additional physics beyond the Standard Model is needed. In both cases novel physics phenomena must set in before these energies are reached. Based on the measured Higgs mass we estimate the critical energy to be in the range of $10^3$ TeV but we also point out that it can potentially be significantly less than that.