DPF - PHENO 2024

EW Portal to the Hidden Valley

15 May 2024, 16:45

15m

David Lawrence Hall 106 (University of Pittsburgh)

Other BSM Physics Beyond the Standard Model

Speaker

LINGFENG LI (Brown U.)

Description

We discuss dark shower signals at the LHC from a dark QCD sector, containing GeV-scale dark pions. The portal with the Standard Model is given by the mixing of the $Z$ boson with a dark $Z^{\prime }$ coupled to the dark quarks. Both mass and kinetic mixings are included, but the mass mixing is the essential ingredient, as it is the only one mediating visible decays of the long-lived dark pions on collider scales. We focus especially on the possibility that the dark $Z^{\prime }$ is {\it lighter} than the $Z$. Indirect constraints are dominated by electroweak precision tests, which we thoroughly discuss, showing that both $Z$-pole and low-energy observables are important. We then recast CMS and LHCb searches for displaced dimuon resonances to dark shower signals initiated by the production of on-shell $Z$ or $Z^{\prime }$, where the visible signature is left by a dark pion decaying to ${\mu }^{+}{\mu }^{-}$. We demonstrate how dark shower topologies have already tested new parameter space in Run 2, reaching better sensitivity on a light dark $Z^{\prime }$ compared to the flavor-changing decays of $B$ mesons, which can produce a single dark pion at a time, and the electroweak precision tests.

Presentation materials

EWPortal_DPFPheno.pdf