Inflationary Physics and LHC Phenomenology in Minimal Gauged U(1)_X Extension of SM

Dr. Digesh Raut (host Dev), University of Alabama
November 30, 2017 at 3:00 pm
241 Comption
Event Description 

Cosmological inflation is the standard paradigm in modern cosmology, according to which our universe experienced a period of rapid accelerated expansion in the very early phase of its evolution. Inflection-point inflation is an interesting possibility to realize a successful slow-roll inflation when inflation is driven by a single scalar field with its value during inflation below the Planck mass. From a particle physics perspective it is interesting if the scalar field (inflaton) plays the role of a Higgs field to spontaneously break some gauge symmetry in new physics models beyond the Standard Model (SM). We consider the inflection-point inflation in the context of the minimal U(1)_X extended SM, and identify the U(1)_X Higgs field with the inflaton field. After taking into account the quantum corrections, the inflaton (Higgs) potential develops an inflection-point if the quartic coupling, during the inflationary period, exhibits a minimum with an almost vanishing value. Requiring that the the inflationary predictions are consistent with the cosmological observation leads to prediction for low energy physics observables which can be tested in the future collider experiments such as the High-Luminosity LHC and the SHiP experiments. Finally, we show that U(1)_X model provides significant enhancement of the production cross sectio n of the heavy right handed neutrinos (RHNs) from the decay of the new U(1)X gauge boson (Z0) in the future LHC experiments, which is crucial for the discovery of RHNs given that the production cross-section of Z0 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 Z0 boson will soon be discovered at the LHC.

Coffee: 2:45 pm, 241 Compton