Mathematisch-Naturwissenschaftliche Fakultät

Institut für Physik

Fachgebiet: Experimentalphysik

Betreuer: PD Dr. Roland Waldi

Christian Voss
(e-mail: )

Measurement of the time reversal asymmetry for the decay anti-B0 -> Lambda0 anti-proton pi+ and observation of the decay anti-Bs0 -> Lambda0 anti-proton K+ with the LHCb experiment

This analysis presents the measurement of the time reversal asymmetry in a baryonic decay of the neutral B meson with the LHCb data collected during 2011 and 2012 of the LHCb experiment located at CERN near Geneva, Switzerland.

A physical system is said to be T invariant, if the equations of motion remain unchanged with respect to the transformation t -> -t. The electro-magnetic and strong interaction are T invariant, but the weak interaction violates T.

T violation is difficult to measure due to the peculiar structure of the quantum mechanical operator. One possibility are triple products constructed with spin and momentum vectors from the decay products of a decaying particle.

Theoretical predictions gave an estimation of the T violating asymmetry of about 10%. The found experimental results are compatible with this predictions but also with the hypothesis of a vanishing asymmetry.

As a second results, this analysis reports the first observation of two baryonic anti-Bs0 decay modes. The Dalitz Plot of these two and the anti-B0 decay mode was studied and a pronounced enhancement at the baryon anti-baryon threshold was found. In addition to that, the angular distributions were studied as well. These help in understanding the underlying mechanisms of the hadronisation as low energy regimes.