Angular distributions probing beyond Standard Models

Abstract: I will discuss the possibility of radiation amplitude zero  (RAZ) in different leptoquark scenarios including scalar and vector. The cross-section of the scattering  involving  a  photon in the initial or  finalstate  can vanish  in  the visible region of the  cosine of the angle  w.r.t  the finalstate  particle in the centre  of  mass  frame. For an electron-photon collider, the  position of  RAZ depends on the charge, mass of  the finalstate particle and  the centre of  mass energy. However,  for an electron-proton collider, where the  photon is in the finalstate, such RAZ only depends on the charge of  the finalstate  particle. A complementary  feature in observing  such RAZ, between electron-photon and  electron-proton, is observed. While RAZ mainly probes the different gauge representations such angular distribution at  the LHC can isolate the spin i.e. the scalar and vector leptoquarks. Finally, we will see that angular distribution can also play an important role of complementarity in determining different possible seesaw scenarios in the muonic colliders.  

Ref: EPJC 80 (2020) 6, 573, EPJC 81 (2021) 4, 315, NPB 971 (2021) 115524, 2011.04191 [hep-ph]