First Beam Particle ID in PandoraPFA Steven Green on behalf of the - - PowerPoint PPT Presentation

S.Green First Beam Particle ID

First Beam Particle ID in PandoraPFA

Steven Green on behalf of the Pandora Team 13th December 2017

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S.Green 2 First Beam Particle ID

Input hits Pandora
 Cosmic Pandora
 Neutrino Pandora
 Cosmic 3D “Slicing” Algorithm Remaining CRs Tag through- going CRs Through-going CRs CR-removed hits Candidate νs

Consolidated event output

ν/Beam Particle ID

Aim: Present the approach taken by Pandora for beam ParticleID in protoDUNE.*

*This is the very first Pandora development related to beam particle ID for protoDUNE and, therefore, is by no means optimised!

Introduction

F

• c

u s

• f

t h i s T a l k

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Identification of Beam Particles

Three variables are used for the identification of the beam particles in Pandora. They will be defined using event displays in the following slides…

First Beam Particle ID

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Identification of Beam Particles

Variable 1: Distance (R) from beam spot to closest CaloHit. Beam Spot R 3D Pandora Event Display

First Beam Particle ID

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Identification of Beam Particles

Identify either: The closest 10% of the 3D CaloHits in the Slice to the beam spot; Or if this 10% contains less than 100 hits, all the CaloHits in the Slice. Beam Spot Red hits are 10% of the hits in the slice closest to the beam spot.

First Beam Particle ID

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Identification of Beam Particles

Perform a fit to these 3D CaloHits to find the major axis. Beam Spot Major axis of a fit to the red hits is shown as a black dotted line.

First Beam Particle ID

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Identification of Beam Particles

Variable 2: Opening angle (θ) between the beam direction and the major axis from the fit. Beam Spot Beam Direction Beam Direction

θ

First Beam Particle ID

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Identification of Beam Particles

Variable 3: The distance (S) between the intersection of the major axis with the TPC and the beam spot Beam Spot Major Axis projected to TPC surface S

First Beam Particle ID

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Target Particles

Before proceeding further, we need to define what a reconstructable particle is. Based on the Particle Momentum distribution, we require that a reconstructable beam particle is

• ne where the primary MC

particle has momentum p such that: Where p is the momentum of the MCParticle in question and ptarget is target beam energy

Particle Momentum [GeV] 5 10 15 20 Entries

2

10

3

10

4

10 Cosmic Ray Beam

Number of Particles

• e

+

e γ

• µ

+

µ p p n n ν

+

π

• π

π

L

K

S

K

+

K

• K

Other

Entries 1 10

2

10

3

10

4

10

5

10 Cosmic Ray Beam

7 GeV Beam + Cosmics

γ

Number of Particles

Other

First Beam Particle ID

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Target Particles

Particle Momentum [GeV] 5 10 15 20 Entries

2

10

3

10

4

10 Cosmic Ray Beam

7 GeV Beam + Cosmics

Target Beam Particles

First Beam Particle ID

S.Green

Intersection Separation 200 400 600 800 1000 Entries 200 400 600 800 1000 1200 1400 1600 4673 Events Beam Cosmics

S Variable 3

Closest Calo Hit Distance [mm] 200 400 600 800 1000 Entries 200 400 600 800 1000 1200 1400 1600 4673 Events Beam Cosmics

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Distributions

Using this definition of target beam particle is, the distribution of the variables we looked at earlier are: Good separation between beam and

• cosmics. ✓

Variable 1

Opening Angle Beam Vs Major Axis 50 100 150 Entries 100 200 300 400 500 600 700 800 4673 Events Beam Cosmics

θ Variable 2

7 GeV Beam + Cosmics

R

First Beam Particle ID

S.Green

Intersection Separation 200 400 600 800 1000 Entries 200 400 600 800 1000 1200 1400 1600 4673 Events Beam Cosmics

S Variable 3

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Closest Calo Hit Distance [mm] 200 400 600 800 1000 Entries 200 400 600 800 1000 1200 1400 1600 4673 Events Beam Cosmics

R

Selection

∴ define beam particles as:

• 1. R < 100 mm
• 2. θ > 150 degrees
• 3. S < 100 mm

Variable 1

Opening Angle Beam Vs Major Axis 50 100 150 Entries 100 200 300 400 500 600 700 800 4673 Events Beam Cosmics

θ Variable 2

7 GeV Beam + Cosmics First Beam Particle ID

S.Green 13 Target Beam Particle Momenta [GeV] 5 − 5 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Signal Efficiency Background Rejection

7 GeV Beam Slice Cosmic Slice Reconstructed As Beam 2492 322 Reconstructed As Cosmic 4009 54499 Example of quality of the beam particle id using the mcc9 samples. Very high background rejection, but it’s needed! Comes at a cost of low signal efficiency. This first approach is highly conservative. Signal Efficiency 0.383 Background Rejection 0.994

Performance

First Beam Particle ID

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Conclusions

The first attempt at beam particle ID in Pandora has been presented and the performance evaluated. The technique is far from perfect and will require further optimisation and development, which we will continue to work on. It does, however, make the Pandora output for a downstream user much easier to use. Thanks to J. Marshall, this logic is included in the latest LArPandoraContent. This code will be included in larsoft v06_60_00 meaning it is available for the mcc10 production. Thank you for your attention. Question?

First Beam Particle ID

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Pandora Team

Framework development LAr TPC algorithm development John Marshall (marshall@hep.phy.cam.ac.uk)
 Mark Thomson (thomson@hep.phy.cam.ac.uk) John Marshall
 Andy Blake (a.blake@lancaster.ac.uk) Please visit https://github.com/PandoraPFA Pandora is an open project and new contributors would be extremely welcome. We’d love to hear from you and we will always try to answer your questions! Contact details: MicroBooNE Lorena Escudero (escudero@hep.phy.cam.ac.uk)
 Joris Jan de Vries (jjd49@hep.phy.cam.ac.uk)
 Jack Anthony (anthony@hep.phy.cam.ac.uk)
 Andy Smith (asmith@hep.phy.cam.ac.uk) ProtoDUNE Steven Green (sg568@hep.phy.cam.ac.uk)

First Beam Particle ID