HET-Discovery seminar by Felix Yu – University of Copenhagen

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HET-Discovery seminar by Felix Yu

Title: The Coannihilation Codex and Mixing Resonance and MET searches
Abstract: We present a general classification of simplified models that lead to dark matter (DM) coannihilation processes of the form DM + X → SM1 + SM2, where X is a coannihilation partner for the DM particle and SM1, SM2 are Standard Model fields. Our classification also encompasses regular DM pair annihilation scenarios if DM and X are identical. Each coannhilation scenario motivates the introduction of a mediating particle M that can either belong to the Standard Model or be a new field, whereby the resulting interactions between the dark sector and the Standard Model are realized as tree-level and dimension-four couplings. We construct a basis of coannihilation models, classified by the SU(3)C×SU(2)L×U(1)Y quantum numbers of DM, X and M. We offer a comprehensive
discussion of the phenomenological features of our models, encompassing the physics of thermal freeze-out, direct and indirect detection constraints, and in particular searches at the Large Hadron Collider (LHC). We discuss how the coannihilation simplified models can be used to connect results from all classes of experiments in a straightforward and transparent way. This point is illustrated with a detailed discussion of the phenomenology of two case studies featuring leptoquark-mediated DM coannihilation and diquark-mediator coannihilation. We emphasize the striking resonance + MET collider signature characteristic of s-channel coannihilation as a particularly well-motivated search complementary to current LHC studies.

References: arXiv:1510.03434 and arXiv:1605.08056