Top quark polarization as a probe of models with extra gauge bosons

Abstract

New heavy gauge bosons exist in many models of new physics beyond the standard model of particle physics. Discovery of these W ′ and Z ′ resonances and the establishment of their spins, couplings, and other quantum numbers would shed light on the gauge structure of the new physics.The measurement of the polarization of the SM fermions from the gauge boson decays would decipher the handedness of the coupling of the new states, an important relic of the primordial new physics symmetry. Since the top quark decays promptly, its decay preserves spin information.We show how decays of new gauge bosons into third generation fermions (W ′ → tb, Z ′ → tt) can be used to determine the handedness of the couplings of the new states and to discriminate among various new physics models.

On extra neutral and charged Higgs bosons at the LHC

“…we should take care of the different origin of the anti-top in two process: thet of process (3) is the decay product of charged Higgs, while thet in process (4) is associated produced with the charged Higgs. We calculate the helicity amplitudes of different processes and obtain their degree of top polarization respectively as [53,54],…”

MultipleZ′→tt¯signals in a 4D composite Higgs model

“…5), owing to the small probability of extracting b (anti)quarks from the proton sea of partons for our typical kinematic configurations, for which value of the Higgs boson. 6 It is given as (here, an increasing number in the label indicates a particle with higher mass)…”

LHC phenomenology of generalSU(2)×SU(2)×U(1)Ježo1, Klasen2, Schienbein3 2012Phys. Rev. D260320View full textAdd to dashboardCite

“…Often denoted as G(221) models, they also appear naturally in larger unification groups like SO (10) and E 6 and in many string theory compactifications and can be classified according to their symmetry breaking pattern [1]. Identification of SUð2Þ 1 with the one of the SM implies in the simplest scenarios the breaking scheme SUð2Þ 2 Â Uð1Þ X !…”