Wire-by-Wire Tracking Efficiency Plots: A New Diagnostic for the Belle~II Central Drift Chamber

TL;DR

This paper introduces a wire-by-wire tracking efficiency diagnostic for the Belle II Central Drift Chamber, enabling detection of localized tracking failures beyond traditional channel-level diagnostics.

Contribution

The paper presents a novel wire-by-wire efficiency diagnostic method, validated on Monte Carlo simulations, that improves tracking failure detection in large detectors.

Findings

Reveals localized tracking failures invisible to conventional diagnostics

Validated method on Monte Carlo with controlled dead-wire conditions

Provides direct feedback for detector operation and aging studies

Abstract

Large detectors are often monitored at the channel level (drift time, collected charge, and hit maps), which validates hardware but not tracking performance. A wire-by-wire tracking efficiency diagnostic is presented for the Belle~II Central Drift Chamber~(CDC). The method is directly analogous to the extrapolation-based efficiency measurement standard in resistive-plate-chamber~(RPC) stacks developed for the India-based Neutrino Observatory~(INO). A reference track (helix) is extrapolated to each wire layer; the fraction of crossings that contain an associated hit defines the per-wire efficiency. Implemented in the Belle~II Data Quality Monitoring~(DQM) framework and validated on Monte Carlo simulation with controlled dead-wire conditions, the method reveals localised tracking failures that are invisible to conventional channel-level diagnostics. The resulting plots provide direct feedback for run selection, operations, and long-term ageing studies.