Transverse Beam Polarization as an Alternate View into New Physics at CLIC

Abstract

In $e^+e^-$ collisions, transverse beam polarization can be a useful tool in studying the properties of particles associated with new physics beyond the Standard Model(SM). However, unlike in the case of measurements associated with longitudinal polarization, the formation of azimuthal asymmetries used to probe this physics in the case of transverse polarization requires both $e^\pm$ beams to be simultaneously polarized. In this paper we discuss the further use of transverse polarization as a probe of new physics models at a high energy, $\sqrt s=3$ TeV version of CLIC. In particular, we show ($i$) how measurements of the sign of these asymmetries is sufficient to discriminate the production of spin-0 supersymmetric states from the spin-1/2 Kaluza-Klein excitations of Universal Extra Dimensions. Simultaneously, the contribution to this asymmetry arising from the potentially large SM $W^+W^-$ background can be made negligibly small. We then show ($ii$) how measurements of such asymmetries and their associated angular distributions on the peak of a new resonant $Z'$-like state can be used to extract precision information on the $Z'$ couplings to the SM fermions.