Natural SUSY Predicts: Higgs Couplings

TL;DR

This paper analyzes Higgs production and decay in natural SUSY models, showing how Higgs observables depend on a few parameters and predicting potential enhancements in diphoton rates within experimental constraints.

Contribution

It provides a simplified parameter framework for Higgs observables in natural SUSY and explores the impact of various extensions on Higgs couplings and decay rates.

Findings

Higgs observables depend on at most four parameters.

Diphoton rate can be enhanced by a factor of 4-6.

Enhancements in diphoton vs. WW/ZZ channels are limited to 1.4.

Abstract

We study Higgs production and decays in the context of natural SUSY, allowing for an extended Higgs sector to account for a 125 GeV lightest Higgs boson. Under broad assumptions, Higgs observables at the LHC depend on at most four free parameters with restricted numerical ranges. Two parameters suffice to describe MSSM particle loops. The MSSM loop contribution to the diphoton rate is constrained from above by direct stop and chargino searches and by electroweak precision tests. Naturalness, in particular in demanding that rare B decays remain consistent with experiment without fine-tuned cancellations, provides a lower (upper) bound to the stop contribution to the Higgs-gluon coupling (Higgs mass). Two parameters suffice to describe Higgs mixing, even in the presence of loop induced non-holomorphic Yukawa couplings. Generic classes of MSSM extensions, that address the fine-tuning problem, predict sizable modifications to the effective bottom Yukawa, yb. Non-decoupling gauge extensions enhance yb, while a heavy SM singlet reduces yb. A factor of 4-6 enhancement in the diphoton rate at the LHC, compared to the SM prediction, can be accommodated. The ratio of the enhancements in the diphoton vs. the WW and ZZ channels cannot exceed 1.4. The h to bbbar rate in associated production cannot exceed the SM rate by more than 50%.