arXiv:1909.12298
Multi-lepton signatures for scalar dark matter searches in coannihilation scenario
Sreemanti Chakraborti, Rashidul Islam
We revisit the scalar singlet dark matter (DM) scenario with a pair of dark lepton partners which form a vector-like Dirac fermionic doublet. The extra doublet couples with the SM leptonic doublet and the scalar singlet via a non-SM-like Yukawa structure. As a result, (1) since the extra fermionic states interact with other dark sector particles as well as the SM via gauge and Yukawa interactions, it gives rise to new DM annihilation processes including pair annihilation as well as coannihilation channels, and (2) such a Yukawa structure opens up new production channels for leptonic final states giving much enhancement in cross sections to search for dark matter in the LHC. Using suitable kinematic observables, we train a Boosted Decision Tree (BDT) classifier to separate enhanced but still feeble light leptonic signal from the backgrounds in an effective manner. On the other hand, same technique is applied to study τ-tagged jets in search for DM signals.