ATLAS · Run 3 · 4D tracking ntuple

Event 220 — interactive vertex display

Every reconstructed and truth vertex plotted at its real (x, y, z) position; each track drawn as a schematic straight segment along its true (θ, φ) direction. Drag to orbit, scroll to zoom, click a legend entry to hide/show a layer.

Reco vertices92
Hard-scatter vtx1
Truth vertices198
Tracks drawn1055
⟨μ⟩193
μ actual193

Encoding

  • Hard-scatter vertex & tracks — diamond marker, size ∝ √∑pT²
  • Pileup (PU) reco vertices — size ∝ √∑pT²
  • PU tracks
  • Truth vertices — small diamonds along the beamline

Reading the plot

  • Transverse (x, y) axes are schematic scale, not to the physical beam-spot scale — the true transverse spread (∼10 μm) would be invisible next to a ∼250 mm beamline.
  • Track lines ignore magnetic curvature and are length-scaled by √pT for visibility, same convention as the companion 2D (z–R) figures.