Probing baryon number with missing energy
- Hiller

Abstract:
Quark portal interactions qqqNqqqN with a light singlet fermion NN make baryon number testable through missing transverse energy (MET). We find that present LHC data constrain scales up to 10 TeV (MET plus jet) and 15 TeV (MET plus top). With increasing mass, or larger portal couplings, NN becomes less long-lived, and gives clean displaced vertex signatures, which encourage dedicated searches. We also narrow down viable mesogenesis models with color triplet scalars to a mass range ∼y (2−3) TeV and couplings y to b- and second generation quarks, a window that can be scrutinized by HL-LHC. Interactions also induce rare decays of type baryon (meson) to meson (baryon) plus invisible, which complement high-p_T searches and can prove baryon number violation. We explore charm decays Λc→(π,K)+invisibleΛc→(π,K)+invisible. Their branching ratios are subject to sizable hadronic uncertainties and require high luminosity flavor facilities such as a Tera-Z facility (FCC-ee, CEPC). Branching ratios of top quarks into one or two b-jets plus N can reach few ×10^−6.
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