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Scan Rules. Introduction Overview Justification Approach Neutrino Event Type Assignment Strategy Muon-Flavor Reaction (mu) Type Electron-Flavor Reaction (e) Type Neutral Current (NC) Type Ambiguous (mu/NC, e/NC) Types Event Topology Classification QE Topology RES Topology
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Scan Rules • Introduction • Overview • Justification • Approach • Neutrino Event Type Assignment • Strategy • Muon-Flavor Reaction (mu) Type • Electron-Flavor Reaction (e) Type • Neutral Current (NC) Type • Ambiguous (mu/NC, e/NC) Types • Event Topology Classification • QE Topology • RES Topology • DIS Topology
Type - Strategy • Identification based on observation of charged lepton track (or lack of for NC) • Scanner must carefully examine: • Hits of an event • Relative pulse heights (PH) • Use Canvases 1 and 2 • Use both U and V projections • Check initially for muon track • If no candidate muon • zoom on event vertex region • use pulse height threshold settings • Look for electron induced EM shower • To help separate ne and NC events • Use canvases 3, 4, and 5 • Examine the longitudinal and transverse energy per plane displays • For ne one should observe • Relatively smooth rise and fall in longitudinal energy • Relatively compact PH profile in transverse energy. • Scanning Tip: • Use the “buttons” provided on the second NueAna canvas to eliminate the lowest PH hits from view to remove Cross-talk and other noise
Type - Muon • Observation of a candidate muon track in the final state • Muons are usually distinctive because of: • Length (longer than hadronic showers) • narrow widths (typically one strip wide) • Relatively low pulse height hits • Should be clearly discernible in both U and V views
Type - Electron • Observation of a candidate electromagnetic shower • Emerges promptly from the primary vertex region • Electromagnetic shower should be recognized by: • relative positions of hits • Pulse height (PH) at each position • Shape of the pattern of hits in the shower • The general shape of an EM shower is an elongated oval • resembles a sine curve, from 0 the p, of low amplitude and long wavelength, and rotated about the axis of the shower direction. • An energetic shower will have: • A central core comprised of hits of largest PH arranged along the shower axis of travel • A “halo” which consists of: • hits outside but directly adjacent to the core • PH should fall off sharply • Should surround the core somewhat uniformly • The width of both the core and the halo should increase (and decrease) with core PH. • The overall topology should be • fairly regular • without large jumps in PH in neighboring planes, or strips • Along the shower core, and after the shower max-PH has been reached and the PH subsequently diminishes, no resurgence of PH should be observed
Type – Electron (cont.) • Size of the pattern of hits in the shower • The size is a function of the electron energy • As the shower energy increases so will • Length • Width • PH’s • Use reconstructed shower energy • Guidelines for events in the 3-10 GeV reconstructed shower energy range • Can be scaled for events with events out of range or towards edges • The central core PH min -- 5 MEUs (both views) • The central core min length – 2 planes (both views) • The total length max -- 12 planes • The core width max -- • 1 to 2 strips across • At most 3 at higher energies • fall sharply (<1/2 max) at either side • The average width max -- 6 hits. • Shower Direction • Shower should align to within 45 degrees of the beam/detector direction. • Note: ne candidates with QE or RES topology will generally align very well with the beam direction, consequently these events will have narrow profiles centered near zero in the U and V view transverse energy per strip profiles
Type – Neutral Current • NO observation of: • Candidate muon track • Electron shower • Comprised entirely of final state hadronic shower(s) • Low multiplicity • single proton (elastic) • single pion (RES) • proton plus pion (RES) • High muliplcity • Higher energy • Multipronged – many tracks • May include small EM showers • From p0 decay • Should not be arranged in a way which is compatible with an evolving shower core – otherwise tagged e or e/NC
Type – Ambiguous • Possible for the final state hadronic system to look comparable to that of a final state charged lepton • Common with low energy CC events and/or high-y CC events • May cause ambiguities • A hit sequence may appear as a plausible candidate lepton in one view but obscured or else indiscernible in the other view • Crossing hadron tracks near vertex may mimic EM shower • Record the event using ambiguous event types • mu/NC • e/NC • e/NC and e/mu/NC may occur but are uncommon and can be accommodated using comment field • In ne flavor search e/NC’s are common.
Topology • Qausielastic (QE) • Charged lepton together with a recoil proton (which may or may not yield detector hits) • Can occur as NC events (elastic) and will appear as one or few high PH hits • Resonance (RES) • A single charged pion track in addition to a charged lepton (and possible recoil proton) • The pion track may be comprised of a few low pulse height hits • The track-like character of the pion may not be obvious • Events include hadronic systems with very modest energy. • Charge current events which have a clearly discernible track accompanying the muon are worthy of note • Events in which the second track is sufficiently long to qualify as a muon are dimuon candidates • Important in charm threshold studies • A comment should be made • Deep Inelastic Scattering (DIS) • Events which have more than one final state hadronic track (in addition to the recoil proton) • Most high energy CC events fall into this category.