Speaker
Description
The Mu2e experiment at Fermilab searches for Charged Lepton Flavor Violation via the coherent conversion of a $\mu^{-}$ to an $e^{-}$ in the Coulomb field of an $\rm{Al}$ nucleus. The signal is a monoenergetic electron with an energy of $104.97~\rm{MeV}$ and the expected single-event sensitivity is $R_{\mu e} < 6.2 \times 10^{-16}$ at $90\%~\rm{C.L.}$ To identify conversion electrons, the Mu2e tracker is composed of transverse straw drift tubes filled with an $\rm{Ar/CO_2}$ gas mixture and arranged with an uninstrumented central region along the beam axis. This geometry suppresses hits from low-momentum particles and improves the efficiency for reconstructing high-momentum tracks. Track reconstruction groups hits into clusters using timing and position information. A new pattern recognition algorithm is being developed that uses the helical trajectory in the azimuthal-longitudinal ($\phi$-$z$) plane to identify helix candidates in a robust way. This method also makes it possible to reconstruct multi-particle events within a single cluster, such as antiproton-induced backgrounds and photon conversions ($\gamma \rightarrow e^{+}e^{-}$) from radiative pion capture. The algorithm and its performance will be presented.