Higgs decay to goldstini and its observability at the LHC

TL;DR

This paper explores the potential for detecting goldstini, arising from multiple supersymmetry breaking sectors, through a novel Higgs decay channel at the LHC, highlighting its observability prospects with high luminosity.

Contribution

It analyzes goldstini couplings in GMSB models and proposes a new Higgs decay mode involving goldstini, assessing its detectability at the LHC.

Findings

Goldstini-photon-neutralino interaction may be very small.

Goldstini-Z-neutralino and Higgs-neutralino interactions can be sizable.

High luminosity LHC could observe the decay if backgrounds are well understood.

Abstract

If supersymmetry is broken independently in multiple sectors with different scales, a number of goldstinos will be generated. One linear combination of these goldstinos is massless and eaten by the gravitino, while the orthogonal combinations acquire a tree level mass and become the physical states named goldstini (G'). Compared to the gravitino, such goldstini could couple more strongly to the visible fields and lead to some exotic phenomenology. In this note we first check the goldstini couplings in some GMSB models and find that the goldstini-photon-neutralino interaction may be very small while the goldstini-Z-neutralino and goldstini-Higgs-neutralino interactions may be sizable. This can induce a new decay mode for the Higgs boson: h-> G'+\chi -> Z+2G'. Then in an effective model with conservative fixed parameters we study the observability of this decay channel at the LHC and find that it is not accessible at the finished 8 TeV run (25 /fb) or 14 TeV run with 100 /fb, but might be observed at the high luminosity LHC (14 TeV, 1000-3000 /fb) if the systematics of the backgrounds can be well understood.