Skip to content
Inflation, Dark Matter, and LHC Phenomenology in Minimal Guaged U(1)$_X$ Extension of SM
November 10, 20171:15 pm – 2:15 pm (CDT)

Inflation, Dark Matter, and LHC Phenomenology in Minimal Guaged U(1)$_X$ Extension of SM


Digesh Raut (University of Alabama)



Mitchell Institute for Fundamental Physics & Astronomy

College Station, Texas 77843

Event Details

In the context of gauged U(1) extension of SM, we discuss the cosmological inflation scenarios, dark matter physics, and LHC phenomenology. We consider minimal U(1)$_X$ extended SM, a generalization of the minimal U(1)$_{B-L}$ model which is realized as a linear combination of the SM U(1)$_Y$ and the U(1)$_{B-L}$ gauge symmetries. In addition to a $B-L$ scalar and a new $Z^\prime$ gauge boson, the model also includes three generations of right handed neutrinos (RHNs) for the anomaly cancellation. With an identification of the $B-L$ scalar to be the inflaton field, we investigate inflection-point inflation which naturally accommodates inflation scenario with initial inflation scale below the Planck mass ($\phi_I \lesssim M_{Pl}$). For a renormalization group improved effective $\lambda \phi^4$ potential to develop an inflection-point with inflationary predictions consistent with the current cosmological observations, the mass ratios among the $Z^\prime$ guage boson, the RHNs, and the inflaton are fixed. In the $B-L$ limit with the gauge boson mass less than $1$ TeV we find that the scenario can be tested in the future collider experiments such as the High-Luminosity LHC and the SHiP experiments. On the other extreme, we consider the scenario such that the U(1)$_X$ gauge symmetry is mostly oriented towards the SM U(1)$_Y$ direction and investigate a consistency between the inflationary predictions and the latest LHC Run-2 results on narrow resonance $Z^\prime$ search with a di-lepton final state. Dark matter (DM) physics is another interesting possibility that we consider. Implementing $Z_2$ parity to one of the RHNs, we investigate the possibility of ``$Z^\prime$ -portal’’ DM scenario to explore the viable parameter region consistent with the relic abundance and the latest LHC Run-2 results on a narrow resonance $Z^\prime$ search with a di-lepton final state. Finally, we consider the prospect of RHN discovery at the LHC via $Z^\prime$ boson decay. U(1)$_X$ model provides significant enhancement of the production cross section of the RHNs from $Z^\prime$ decay in the future LHC experiments, which is crucial for the discovery of RHNs given that the production cross-section of $Z^\prime$ boson via di-lepton resonance is severely constrained. Taking this into account, we conclude that the possibility of discovering the RHNs in the future implies that the $Z^\prime$ boson will soon be discovered at the LHC.

Copyright © 2024. All rights reserved, Texas A&M University Trademark | Texas A&M University, College Station, Texas 77843