International Center for Advanced Studies

Manuel Szewc

PhD Student @ ICAS since April 2018

  • Full Name: Manuel Szewc
  • Contact:
  • Position: PhD Student at ICAS-UNSAM & Teaching Assistant at University of Buenos Aires (UBA)
  • Brief trajectory: Licenciado en Ciencias FĂ­sicas (similar to M.Sc. on Physics), Physics Department, FCEN, University of Buenos Aires
  • Current research: Searching for New Physics in LHC
  • Main interests: High Energy Phenomenology, Top Physics, Dark Matter

What's the difference between CP even and CP odd spin-0 particles when coupling to fermions?

In my master thesis (done under the supervision of E. Alvarez and A. Szynkman), we studied how exactly does the CP nature of a spin-0 particle (like the Higgs boson) impacts its coupling with fermions. We studied both the decay of a spin-0 particle h/A->ffbar and the LHC proccess pp->tth/A which has a noticeable difference in the pT-distribution of the resulting CP even or CP odd spin-0 particle .

Some conclusions came up:
  • The CP nature of the spin-0 particle affects the relative sign between the chirality currents.
  • The difference depends on whether the fermions are massless or massive. This is due to the physical fermions being helicity eigenstates. When the fermions are massless, helicity and chirality have a common basis and the relative sign between chiralty currents is unimportant. However, when the fermions are massive, the relative sign matters.
  • If the fermions are massive, orbital momentum provides a good quantum number which is sensible to the CP nature of the spin-0 particle.

Hobbies and interests