Estimating K-long identification efficiency with the KLM detector at the Belle II experiment
Grade Level at Time of Presentation
Senior
Major
Mechanical Engineer
Institution 25-26
University of Louisville
Faculty Advisor/ Mentor
Swagato Banerjee, Ph.D.
Department
Department of Physics and Astronomy
Abstract
The detection and reconstruction of long-lived neutral kaons (KL0) presents a persistent challenge in high-energy collider experiments due to their neutral charge, long lifetime, and weak interactions with detector material. They are identified by the energy deposits in the K-long and muon (KLM) detector in the Belle II experiment, which collects data from electron–positron collisions at center-of-mass energies near 10.58 GeV at the asymmetric-energy collider SuperKEKB in Japan. However, photons, neutrons, and other neutral hadrons can also deposit energy in the KLM detector. Additionally, while the resistive plate chambers in the KLM provide directional information, they do not directly yield momentum measurements, limiting full kinematic reconstruction.
Here we present a statistical technique to discriminate between the patterns of energy deposits in the KLM from KL0 versus other backgrounds using charm-pair events which decay via the control channel D*± → D0 [→ KL0 π+ π−] π±. This technique allows a direct comparison of data with Monte Carlo simulated events, providing a robust estimation of KL0 identification efficiency in the KLM detector. This work contributes to improved neutral-hadron reconstruction and enhances the physics reach of Belle II analyses involving missing energy and flavor physics observables.
Estimating K-long identification efficiency with the KLM detector at the Belle II experiment
The detection and reconstruction of long-lived neutral kaons (KL0) presents a persistent challenge in high-energy collider experiments due to their neutral charge, long lifetime, and weak interactions with detector material. They are identified by the energy deposits in the K-long and muon (KLM) detector in the Belle II experiment, which collects data from electron–positron collisions at center-of-mass energies near 10.58 GeV at the asymmetric-energy collider SuperKEKB in Japan. However, photons, neutrons, and other neutral hadrons can also deposit energy in the KLM detector. Additionally, while the resistive plate chambers in the KLM provide directional information, they do not directly yield momentum measurements, limiting full kinematic reconstruction.
Here we present a statistical technique to discriminate between the patterns of energy deposits in the KLM from KL0 versus other backgrounds using charm-pair events which decay via the control channel D*± → D0 [→ KL0 π+ π−] π±. This technique allows a direct comparison of data with Monte Carlo simulated events, providing a robust estimation of KL0 identification efficiency in the KLM detector. This work contributes to improved neutral-hadron reconstruction and enhances the physics reach of Belle II analyses involving missing energy and flavor physics observables.