Pion Analysis Absorption + Charge Exchange Jake Calcutt July 11, - - PowerPoint PPT Presentation

Jake Calcutt July 11, 2019

Pion Analysis

Absorption + Charge Exchange

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Introduction

In addition to the total (elastic + inelastic) cross section, exclusive (subsets of inelastic) pion-Ar cross sections provide useful information Have the added benefit of unique signals Exclusive channels:

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My Goal

For now: build an event selection for Absorption and Charge Exchange events Eventually: Make a cross section measurement across range of momenta This talk: shows some studies of MCC11 in my progress towards the event selection

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Event Topologies

π+ X π+ X π0

Absorption Charge Exchange

X = Nucleons

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Signal Definiton

Birds eye view: Pion interaction with no charged pions in final state

• Look for interactions without MIP in final state
• Attempted cutting on average dE/dX along the track

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dE/dX of Daughter Tracks

Looked at all reconstructed daughters coming out of the primary pion tracks Averaged dE/dX from Collection plane by number of hits Backtracked reco daughters to true PDG (provided by the MCParticle contributing the most deposited energy)

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dE/dX of Daughter Tracks

Abs+Cex All BG Pion Interactions Abs Cex

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Observations

Within this signal there should be no charged pion daughters Scanning these events showed that these backtracked to the incident pions More on this later

Abs+Cex

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Observations

Particularly in Absorption, there is a peak in dE/dX < 2 MeV for protons Need to investigate

Abs

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Observations

The gammas from the pi0 decays are quite often reconstructed as tracks, and contaminate the MIP-like region Will come back to this in a few slides

Cex

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Observations

Muons are sometimes associated as daughters to the signal Later: I have some insight on this

Cex

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Pions Associated as Daughters

Cursory glance at events show tracks splitting at elastic scatters This is working as intended (I did not realize this at first)

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Need to change the way I treat/think about these tracks Normally, I think about pions similar to Geant: the pion is one track up to the inelastic interaction/decay → elastic scatters along the track are included in this Now: Should I treat this as BG? What about low-angle elastic scatters that aren’t reconstructed?

Pions Associated as Daughters

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π0 Decay Gammas

The shower CNN ID can be used to pick out gammas from π0 decays and disregard during MIP-rejection Sum up scores from all hits in a track, divide by N hits

Cex BG

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χ2-based PID

Tingjun pointed me to a PID technique developed for MicroBooNE: Fitting reconstructed dEdX vs Range to proton template More sophisticated than average dEdX along the track

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χ2-based PID

Abs+Cex BG Still need to deal with Pi0 decay and charged pion reco “issues” Implemented in ProtoDUNETrackUtils

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Muon Daughter Tracks

Started investigating where muons are coming from (should be none from Decay since I’m only looking at EndProcess == “pi+Inelastic”) Looking at true origin and backtracking the parent particles Decay: product of primary decay Decay+: primary daughter decay Decay++: primary granddaughter decay

Abs+Cex events 2 Total

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Muon Daughter Tracks

Started investigating where muons are coming from (should be none from Decay since I’m only looking at EndProcess == “pi+Inelastic”) Looking at true origin and backtracking the parent particles Decay: product of primary decay Decay+: primary daughter decay Decay++: primary granddaughter decay

BG events

More downstream decays from π+ → π∓

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Daughter Track Starting Points

Investigating why cosmics are assigned as daughters. Tried looking at distance to end of primary track Note: distance comes from closer of start or end of daughter track to end of primary track

Abs+Cex BG

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Daughter Track Starting Points

Hand scanning a few events from

• MC. I noticed this interesting case

(High stats sample w/ sce, run 2, subrun 3, event 484) Beam π+ (28) has an elastic scatter, Pandora recognizes this and creates a new track (23). It ends in an inelastic interaction and creates a proton (70) that is associated as 28’s daughter. Additionally, a cosmic (30) is associated as a daughter

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To-Do

• Reconsider how I’m treating elastic scatters before the inelastic

interaction

• Disregard Pi0-gammas in MIP-rejection in daughter tracks
• Look into shower daughter information
• Look at MCC12 (these studies was done using MCC11)

Thanks for listening

Jake Calcutt