Jun 26 – 27, 2023
America/Chicago timezone

Estimation of Combinatoric Background in SeaQuest using an Event-Mixing Method

Jun 27, 2023, 8:15 AM
One West (Fermilab)

One West



Abinash Pun (New Mexico State University)


The $J/\psi$ particle is a spin-1 charmonium state with significant decay fraction towards lepton pairs. The distribution of decay particles from the $J/\psi$ is influenced by its spin alignment, which provides insights into different production mechanisms. SeaQuest, a fixed target experiment at Fermilab, was designed to observe muon pairs from charmonium and Drell-Yan production in $pp$ and $pd$ interactions. The dimuons, produced from $J/\Psi\rightarrow\mu^+\mu^-$ decays, recorded by SeaQuest can be utilized to examine the spin alignment of the $J/\psi$ particle. In addition to the desired dimuon signals, the recorded data also includes combinations of two muon tracks that do not originate from a common physics vertex. We present an event-mixing method that accurately calculates this combinatorial background with appropriate normalization. This method can be extended for use in other experiments that observe dilepton pairs.

Primary author

Abinash Pun (New Mexico State University)

Presentation materials