# APEC Seminar (Astronomy - Particle Physics - Experimental Physics - Cosmology)

Speaker: Ke-Pan Xie (Seoul National University) Broad composite resoance and its signals at the LHC Fri, Mar 01, 2019, 13:30 - 14:30 Seminar Room A 2222.pdf The existence of the $SU(2)_L$ triplet composite spin-1 resonances $\rho^{\pm,0}$ is a universal prediction of the strongly interacting new physics models addressing the naturalness problem. Although being plausible, such resonances are not found yet in the di-boson final states (i.e. $W^\pm Z/W^\pm h$, $W^+W^-/Zh$), which are expected to be the dominant decay channels of the $\rho$s. In this work we propose a new scenario that the $\rho$-resonances might be broad and mainly decay to the third generation quarks, in which the left-handed quark doublet $q_L = (t_L, b_L)$ is fully composite. In this case, The $t\bar{t}$ resonance search channel is comparable in sensitivity to the di-lepton channel. We also discuss how to use deep learning to improve the efficiency in the search for such a broad resonance.