Pion scattering with the Pion scattering with the LArIAT experiment - - PowerPoint PPT Presentation
Pion scattering with the Pion scattering with the LArIAT experiment LArIAT experiment Justin Hugon (On behalf of the LArIAT experiment) Louisiana State University 1 Liquid Argon in a Test Beam (LArIAT) Liquid Argon in a Test Beam (LArIAT)
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Justin Hugon (On behalf of the LArIAT experiment) Louisiana State University
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47 cm 47 cm Drift Direction Drift Direction Beam Direction Beam Direction 90 cm 90 cm 40 cm 40 cm
LArIAT TPC LArIAT TPC
Reuse the ArgoNEUT TPC in a charged particle beam at Fermilab
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Changes from ArgoNEUT:
C a t h
e p l a n e Wi r e / a n
e p l a n e s R e a d
t A S I C s
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– Hadron-Ar interaction cross sections
– e/g shower identification capabilities – Anti-proton annihilation at rest
– Particle sign determination in the absence of a magnetic field, utilizing topology
– Ionization and scintillation light studies
– Optimization of particle ID techniques – LArTPC event reconstruction
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the Fermilab test-beam facility (FTBF)
80 GeV, directed toward the LArIAT experimental hall
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D i p
e M a g n e t s H a l
e t
u
P u n c h t h r
g h V e t
u
R a n g e S t a c k M u l t i
i r e p r
t i
a l c h a m b e r s ( M WP C s ) C
l i m a t
s A e r
e l C e r e n k
C
n t e r s
T P C
S e c
d a r y b e a m
p’
s ( 8
G e V )
C u t a r g e t
T i m e
F l i g h t ( T O F )
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Wire chambers reconstruct the position and momentum of the particles in the beamline
Wire chamber reconstructed momentum compared to simulation
LArIAT Preliminary
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2 scintillator counters w/ ~1ns sampling, provide the time of flight (TOF)
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Combining the momentum and TOF allows for p/m/e, K, proton separation Additionally, using the known masses of the K and proton we can constrain the momentum scale to 1.5%
TOF vs reconstructed momentum
LArIAT Preliminary
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reconstructed in the beamline and extrapolate it to the LArTPC and look for a match
– We match in both position
(+/- 5cm about the mean) and angle (< 10o)
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can characterize the dE/dX response as a function of the track’s initial momentum in both data and simulation
formula by selecting events with different particle type and momentum
LArIAT Preliminary
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another calibration sample
– Width of dE/dx distribution
can be compared between data and simulation
makes the simulation match the data
LArIAT Preliminary Events / (0.1 MeV/cm) LArIAT Preliminary
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estimate what our fractional beam composition and our selection efficiencies are for the various particle species
LArIAT Preliminary
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A b s
p t i
C a n d i d a t e ( π
3 p )
LArIAT Data
C h a r g e E x c h a n g e C a n d i d a t e
LArIAT Data LArIAT Data
π P r
u c t i
C a n d i d a t e
LArIAT Data
I n e l a s t i c S c a t t e r i n g C a n d i d a t e
LArIAT Data
LArIAT Data
E l a s t i c S c a t t e r i n g C a n d i d a t e
LArIAT Data
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LArIAT Data
π D e c a y C a n d i d a t e
LArIAT Data
π C a p t u r e C a n d i d a t e
LArIAT Data
Mu
B a c k g r
n d
LArIAT Data
Note: Pion decay backgrounds are small component which remain in our result. Capture dominates the lowest energy bin and is thus excluded
LArIAT Simulation LArIAT Simulation Pion Interaction Type per Kinetic Energy Pion Interaction Fraction per Kinetic Energy
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where we measure the probability of interacting for that thin slab as the ratio of the number of interacting pions to the number of incident pions:
−σn z
−σ nz
probability of a pion traveling through a thin slab of argon is given by: Where σTOT is the cross-section per nucleon, z is the depth of the slab, and n is the density
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function of energy as
Where n = rNA / A
wire-to-wire spacing as a series of “thin-slab” targets if we know the energy of the pion incident to that target PInteracting=1−(1−σ nδ z+...) σ(E)≈ 1 nz PInteracting=1 nz N interacting NIncident
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p-candidate's initial kinetic energy as we take into account energy loss due to material upstream of the TPC (argon, steel, beamline detectors, etc)
point as a “thin slice” of argon which the pion is incident to at a known energy
2+mp 2−mp−EFlat
Interacting Incident
Kinetic Energy (MeV) Kinetic Energy (MeV)
KE Interaction=KE i−∑
i=0 nSpts
dE/dX i×Pitchi
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Interacting Incident
Kinetic Energy (MeV) Kinetic Energy (MeV)
KE Interaction=KE i−∑
i=0 nSpts
dE/dX i×Pitchi
Interacting Incident
Kinetic Energy (MeV) Kinetic Energy (MeV)
We ignore other tracks in the event not matched to the Wire Chamber Track
When you encounter the interaction point you now fill the interacting and incident histogram for the energy the pion has at that point You now repeat this process for your entire sample
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these two histograms to extract the cross-section
Interacting Incident
Where n = rNA / A
σ(E)≈ 1 nz PInteracting=1 nz N interacting NIncident
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Systematics Considered Here dE/dX Calibration: 3% (previously was 5%) (previously was 5%) Energy Loss Prior to entering the TPC: 3.5% Through Going Muon Contamination: 3% Wire Chamber Momentum Uncertainty: 3%
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exchange: p + Ar → 0π± + X
– Useful for modeling contamination of ν CC
QE from CC RES where a π is absorbed in the interaction nucleus
– Need to identify outgoing pions v. protons
A b s
p t i
C a n d i d a t e ( π
3 p )
LArIAT Data
C h a r g e E x c h a n g e C a n d i d a t e
LArIAT Data LArIAT Data
Signal Events: 0 Secondary π± Background Events: Contain Secondary π±
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residual range of each track hit
– Constructed from simulated tracks – Evaluate using likelihood-ratio of
all hits on a track
Proton Likelihood Pion Likelihood
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p-candidate
g g
g g g g g g
halo muon
multi-nucleon
O(20) anti-proton annihilation at rest candidates
– O(70) annihilation in flight
– DUNE planning search
LArIAT Data LArIAT Data p-candidate Work ongoing to reconstruct these final state topologies
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section has O(2000) Elastic/Inelastic interactions identified
– Inclusive cross-section
coming soon
argon
– Work ongoing to
reconstruct these final state topologies
p → K+ ν
signal efficiency is modeled properly
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– New result has x100 the initial statistics
calibration
– Paper in preparation
physics run
– Run-I / Run-II: 4mm wire pitch
– Run-III: 3mm / 5mm wire pitch
comparison
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behind this result
– Inclusive K+ Cross-section – Inclusive p+ Cross-section
along too
– Anti-proton annihilation at rest – e/g shower characterization
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30 Neutrino interaction in LAr produces ionization and scintillation light Drift the ionization charge in a uniform electric field Read out charge and light produced using precision wires and PMT's
Electric Field Electric Field Electric Field
g g g g g g
nm
g
Induction Induction Plane Plane Collection Collection Plane Plane
⊕ ⊕ Drift
Drift Time Time = ✔ 3D imaging with mm 3D imaging with mm space resolution space resolution ✔ Calorimetry information Calorimetry information ✔ PID capabilities PID capabilities
Wire Number Time Tick Wire Number Time Tick
LArIAT Data LArIAT Data K+ → µ+ → e+ Candidate K+ → µ+ → e+ Candidate
Bragg peak
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T i me
F l i g h t ( T O F )
H a l
e t
u
R a n g e S t a c k
g e l k
t e r s
T P C
the region before it enters the TPC (TOF, Halo, Cryostat Cryostat, Argon Argon) gives us the “energy loss” by the pion in the upstream region
Gaussian Fit from 35 – 55 MeV
KEi=√ p
2+mp 2−mp−EFlat
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n=1.11 Aerogel n=1.057 Aerogel
200-300 MeV/c µ π µ π 300-400 MeV/c µ π µ π
A G
T O F
W C 1 W C 2 W C 3 W C 4
T O F
LArTPC
Muon Range Stack
Magnet Magnet
α α
LArIAT Beamline Detectors LArIAT Beamline Detectors
✔ Allows to perform p/m separation
✔ Currently under investigation
π π μ μ
✔ Four layers of XY planes sandwiched between (pink) steel slabs ✔ Each plane is composed by 4 scintillating bars connected to a PMT ✔ Allows to discriminate p/m exiting the cryostat ✔ Currently under investigation
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Inside the cryostat: TPC and light collection system Inside the cryostat: TPC and light collection system
1 2 3 4
Cathode Cathode WirePlanes WirePlanes Pulse shaping Pulse shaping and amplifying and amplifying cold ASICs cold ASICs
Light Light Collection Collection System port System port
SiPM: Hmm. VUV-sensitive (Run II)
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Conversion-on-PMTs only LArIAT solution
Light Collection System Light Collection System
TPB Field Cage Wall Reflector
Reflector Foils Reflector Foils
Credit: W. Foreman
✔ Wavelength shifting (evaporated) reflected foils on the four field cage walls
✔ Technique borrowed from dark matter experiments
✔ Provides greater (~ 40 pe/MeV at zero field) and more uniform light yield respect to “conversion-on-PMTs-only” light systems ✔ R&D for future neutrino experiments as a way to improve calorimetry and triggering
Beam direction
PMTs
x
z
Beam direction Beam direction
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New ARAPUCA Light Collection System New ARAPUCA Light Collection System
wavelength shifter
– Trap light inside device
Teflon
– Trapped light reflected
until detected by SiPM
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New ARAPUCA Light Collection System New ARAPUCA Light Collection System
existing PMTs
– Compare ARAPUCA performance
to PMTs
2x Ganged SiPM
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– Here we show events / 50 MeV bin to mimic the binning used in the data – Plot the true kinetic energy
– Constitutes ~80% of the interactions in that bin – This is not a process we want to include in the cross-section measurement
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before reaching the TPC
– The remaining portion there is actually an interaction
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