Time-delayed electrons from neutral currents at the LHC

We investigate long-lived particles (LLPs) produced in pair from neutral currents and decaying into a displaced electron plus two jets at the LHC, utilizing the proposed minimum ionizing particle timing detector at CMS. We study two benchmark models: the R-parity-violating supersymmetry with the lightest neutralinos being the lightest supersymmetric particle and two different U(1) extensions of the standard model with heavy neutral leptons (HNLs). The light neutralinos are produced from the standard model Z-boson decays via small Higgsino components, and the HNLs arise from decays of a heavy gauge boson, Z′. By simulating the signal processes at the HL-LHC with the center-of-mass energy $$ \sqrt{s} $$ s = 14 TeV and integrated luminosity of 3 ab−1, our analyses indicate that the search strategy based on a timing trigger and the final state kinematics has the potential to probe the parameter space that is complementary to other traditional LLP search strategies such as those based on the displaced vertex.

Diphoton channel at the LHC experiments to find a hint for a new heavy gauge boson

Recently there has been a huge interest in the diphoton excess around 750 GeV reported by both ATLAS and CMS collaborations, although the newest analysis with more statistics does not seem to support the excess. Nevertheless, the diphoton channel at the LHC experiments are a powerful tool to probe a new physics. One of the most natural explanations of a diphoton excess, if it occurs, could be a new scalar boson with exotic colored particles. In this setup, it would be legitimate to ask what is the role of this new scalar in nature. A heavy neutral gauge boson [Formula: see text] is one of the traditional targets of the discovery at the collider experiments with numerous motivations. While the Landau–Yang theorem dictates the diphoton excess cannot be this spin-1 gauge boson, there is a strong correlation of a new heavy gauge boson and a new scalar boson which provides a mass to the gauge boson being at the same mass scale. In this paper, we point out a simple fact that a new scalar with a property similar to the recently highlighted 750 GeV would suggest an existence of a TeV scale [Formula: see text] gauge boson that might be within the reach of the LHC Run 2 experiments. We take a scenario of the well-motivated and popular gauged [Formula: see text] symmetry and require the gauge coupling unification to predict the mass and other properties of the [Formula: see text] and illustrate the discovery of the [Formula: see text] would occur during the LHC experiments.