Dimuon enhancement at 28 GeV and tentative (pseudo)scalar partner of the Z boson at 57.5 GeV

TL;DR

This paper investigates potential new particles suggested by dimuon excesses at 28 GeV and 57.5 GeV, analyzing whether these signals could originate from Z boson decays involving a (pseudo)scalar partner.

Contribution

It proposes a possible interpretation of the dimuon excesses as decay products of a (pseudo)scalar boson around 57.5 GeV linked to Z boson decays, offering a new perspective on these anomalies.

Findings

Data may originate from Z boson radiative decays involving a new boson.

Possible connection between dimuon excesses and a (pseudo)scalar partner of the Z.

Analysis supports the hypothesis of a new boson at 57.5 GeV.

Abstract

The CMS Collaboration at the LHC recently reported an accumulation of data around 28 GeV in the invariant-mass distribution of muon pairs in association with a b quark jet and at least a second jet. This is analysed here in the light of the possible existence of a (pseudo)scalar boson with mass of about 57.5 GeV. We find that part of the data may originate in the radiative decay of Z bosons into pairs consisting of the lighter boson and a photon, giving rise to dimuon decay products that either stem from the photon or from the (pseudo)scalar boson.