Speaker
Description
We consider the non-minimal quartic inflation driven by the U(1)$_X$ Higgs field $\phi$ in classically conformal U(1)$_X$ extended Standard Model (SM). Since the conformal symmetry is broken radiatively, the U(1)$_X$ gauge boson mass $m_{Z^\prime}$, the U(1)$_X$ gauge coupling $g_X$, and the inflationary predictions for tensor-to-scaler ratio $r$ are determined by only two free parameters, the inflaton mass $m_\phi$ and its mixing angle $\theta$ with the SM Higgs field. We show that the new FASER experiment at the High-Luminosity LHC (HL-LHC) can detect the inflaton in both cases if the mass is in the range 0.1 ≲ $m_{\phi}$ [GeV] ≲ 4. We show that the searches for primordial gravitational waves, collider searches for $Z^\prime$ at the LHC, and long-lived particle searches at experiments like FASER are complementary in the hunt for inflation. By performing a comparative study of the metric and Palatini formulations of gravity, we demonstrate that the two formulations are distinguishable.
