t2k nd280 cross section results and future prospects · t2k nd280 cross section results and future...
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T2K ND280 cross section results and future prospects
Kendall Mahn (Michigan State University)
for the T2K collaboration
J-PARC symposium Sep 26th 2019
NuI
nt20
14 g
raph
ic
Support provided by U.S. DOE Award DE-
SC0015903
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T2K ND280 cross section results and future prospects
Kendall Mahn (Michigan State University)
for the T2K collaboration
J-PARC symposium Sep 26th 2019
NuI
nt20
14 g
raph
ic
Support provided by U.S. DOE Award DE-
SC0015903
3
How an oscillation analysis works: in one slideFHC ⌫µ Flux (arbitrary norm.)NEUT 5.3.6, �⌫µch (E⌫)
CC-Total
CC-RES
CC-1p1h+2p2h
NC-Total NC-RES
T2K: ND o↵-axis
[1707.01048] B.F.
Super-K oscillated
0
0.5
1
1.5
2
�(E
⌫)/E
⌫(1038cm
2nucleon�1GeV
�1)
0 1 2 3 4 5
E⌫ (GeV)
N↵!�FD (Ereco) =
X
i
�↵(Etrue)⇥ �i�(Etrue)⇥ P↵�(Etrue)⇥ ✏�(Etrue)⇥Ri(Etrue;Ereco)
Event rate is used to determine oscillation, and depends on the flux (𝛷) and interaction model
(cross section, σ), efficiency and response
between truth and observables (R)
4
N↵!�FD (Ereco) =
X
i
�↵(Etrue)⇥ �i�(Etrue)⇥ P↵�(Etrue)⇥ ✏�(Etrue)⇥Ri(Etrue;Ereco)
FHC ⌫µ Flux (arbitrary norm.)NEUT 5.3.6, �⌫µch (E⌫)
CC-Total
CC-RES
CC-1p1h+2p2h
NC-Total NC-RES
T2K: ND o↵-axis
[1707.01048] B.F.
Super-K oscillated
0
0.5
1
1.5
2
�(E
⌫)/E
⌫(1038cm
2nucleon�1GeV
�1)
0 1 2 3 4 5
E⌫ (GeV)
Requirement for model: Correct energy
dependance for all relevant processes
Interaction models play a critical role
5
N↵!�FD (Ereco) =
X
i
�↵(Etrue)⇥ �i�(Etrue)⇥ P↵�(Etrue)⇥ ✏�(Etrue)⇥Ri(Etrue;Ereco)
RHC ⌫̄µ Flux (arbitrary norm.)NEUT 5.3.6, �⌫̄µch (E⌫)
CC-Total
CC-N⇡+DIS
CC-RES
CC-1p1h+2p2h
T2K: ND o↵-axis
[1707.01048] B.F.
Super-K oscillated
0
0.2
0.4
0.6
0.8
1
�(E
⌫)/E
⌫(1038cm
2nucleon�1GeV
�1)
0 1 2 3 4 5
E⌫ (GeV)
Requirement for model: All neutrino flavors! for relevant
processes
Interaction models play a critical role
6
N↵!�FD (Ereco) =
X
i
�↵(Etrue)⇥ �i�(Etrue)⇥ P↵�(Etrue)⇥ ✏�(Etrue)⇥Ri(Etrue;Ereco)
RHC ⌫̄µ Flux (arbitrary norm.)NEUT 5.3.6, �⌫̄µch (E⌫)
CC-Total
CC-N⇡+DIS
CC-RES
CC-1p1h+2p2h
T2K: ND o↵-axis
[1707.01048] B.F.
Super-K oscillated
0
0.2
0.4
0.6
0.8
1
�(E
⌫)/E
⌫(1038cm
2nucleon�1GeV
�1)
0 1 2 3 4 5
E⌫ (GeV)
Interaction models play a critical roleRequirement for model:
- All visible particles for efficiency (background) and energy estimates
Requirement for model: - Correct mix of
processes per topology - true - reconstructed
kinematic relationship
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T2K’s capabilities for cross section (XSEC) measurements
E⌫ (GeV)0 1 2 3 4 5
�(E
⌫)/E
⌫(103
8cm
2nu
cleon�1GeV
�1)
0
0.5
1
1.5
2
⌫µ Flux (arbitrary norm.)GENIE 2.12.8, �⌫µch (E⌫)
CC-Total
CC-RES
CC 1p1h+2p2h
T2K: ND o↵-axis
T2K: ND on-axis
MINER⌫A L.E.
• Processes of interest:
• Charged current and neutral current
• Quasi-elastic (1p1h), multinucleon (2p2h), single pion production (SPP)
• Measure final state topology: CC0π,
W"
CCQE
νµ"
N’"N"
µ�"
"
W"
2p2h
νµ"
N’,N’"N,"N"
µ�"
"
W"
νµ""
N"N’"
Δ"π"
CCπ"" µ�""
W"
νµ""
A"
π+"
CCπ"" µ�""
A"
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T2K’s capabilities for cross section (XSEC) measurements
E⌫ (GeV)0 1 2 3 4 5
�(E
⌫)/E
⌫(103
8cm
2nu
cleon�1GeV
�1)
0
0.5
1
1.5
2
⌫µ Flux (arbitrary norm.)GENIE 2.12.8, �⌫µch (E⌫)
CC-Total
CC-RES
CC 1p1h+2p2h
T2K: ND o↵-axis
T2K: ND on-axis
MINER⌫A L.E.
• Measure final state topology:
• CC0π (no charged or neutral pion in the final state)
• CC1π+ (one charged pion in the final state)
PRD 99, 052007 (2019)
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T2K’s capabilities for cross section (XSEC) measurements
E⌫ (GeV)0 1 2 3 4 5
�(E
⌫)/E
⌫(103
8cm
2nu
cleon�1GeV
�1)
0
0.5
1
1.5
2
⌫µ Flux (arbitrary norm.)GENIE 2.12.8, �⌫µch (E⌫)
CC-Total
CC-RES
CC 1p1h+2p2h
T2K: ND o↵-axis
T2K: ND on-axis
MINER⌫A L.E.
• Multiple detectors with a variety of detection capabilities
• Near: ND280 (soon ND upgrade)
• Far: Super-Kamiokande
• Near: INGRID, WAGASCI+BabyMIND
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T2K’s capabilities for cross section (XSEC) measurements
• Well-understood beam: recently improved flux uncertainties (esp. data from NA61 and soon EMPHATIC); neutrino and antineutrino-modes
T2K Preliminary
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Global program requires multiple measurements
Osc experiment Target cross sections from
T2K, NOvA Scintillator T2K, NOvA ND, MINERvA LE, HE
T2K, SK, IceCube Water T2K (INGRID, WAGASCI, ND280), MINERvA
DUNE Ar T2K ND upgrade, MicroBooNE/SBN, MINERvA
• T2K near detectors have multiple targets: C, H2O, Fe and Ar, Pb
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Global program requires multiple measurements
Osc experiment Target cross sections from
T2K, NOvA Scintillator T2K, NOvA ND, MINERvA LE, HE
T2K, SK, IceCube Water T2K (INGRID, WAGASCI, ND280), MINERvA
DUNE Ar T2K ND upgrade, MicroBooNE/SBN, MINERvA
• T2K near detectors have multiple targets: C, H2O, Fe and Ar, Pb
Interaction in ND280 TPC’s gas (predominantly Ar)
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Global program requires multiple measurements dσ/dQ2 vs. Eν: QE, single nucleon
(McFarland, Ruterbories)
Osc experiment Target cross sections from
T2K, NOvA Scintillator T2K, NOvA ND, MINERvA LE, HE
T2K, SK, IceCube Water T2K (INGRID, WAGASCI, ND280), MINERvA
DUNE Ar T2K ND upgrade, MicroBooNE/SBN, MINERvA
E⌫(GeV)Ann. Rev. Nucl. Part. Sci. 68, 105 (2018)
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Global program requires multiple measurements dσ/dQ2 vs. Eν: QE, single nucleon
(McFarland, Ruterbories)
Osc experiment Target cross sections from
T2K, NOvA Scintillator T2K, NOvA ND, MINERvA LE, HE
T2K, SK, IceCube Water T2K (INGRID, WAGASCI, ND280), MINERvA
DUNE Ar T2K ND upgrade, MicroBooNE/SBN, MINERvA
E⌫(GeV)
Additional physics programs depend on these measurements:Anything that also relies on neutrino beams as background, so
especially exotic searches:sterile neutrino searches, dark matter searches, proton decay, etc
Ann. Rev. Nucl. Part. Sci. 68, 105 (2018)
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20152016
2018
PRD96 no.9, 092006
Timeline of T2K cross section results
PRD96 no.5, 052001
2017
PRD 98, no. 3, 032003
PRD 98, 012004
PRD 97, no. 1, 012001
PRL117, no.19, 192501
PRD95, no.1, 012010
PRD93, no.11, 112012
PRD93, 072002PRD91, no.11, 112002
PRD92, no.11, 112003
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• New window (hadronic state) on neutrino interactions: Kinematic variables relative to the beam direction are sensitive to nuclear effects.
• Semi inclusive scattering of protons out of CCQE-like interactions; paper in preparation includes proton multiplicity as well
“Transverse variables”
PRC94 (2016) no.1, 015503
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• New window (hadronic state) on neutrino interactions: Kinematic variables relative to the beam direction are sensitive to nuclear effects.
• Semi inclusive scattering of protons out of CCQE-like interactions;”0π+p”
PRC94 (2016) no.1, 015503
“Transverse variables”
PRD 98, 032003 (2018)
T2K
T2K Cross Section 2018 Highlights
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CC0π on water, antineutrinos, off-
axis flux
World first!
muonNeutrino
T2K preliminary
Detailed information in differential cross section (in muon kinematics)
T2K Cross Section 2018 Highlights
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CC0π on water, antineutrinos, off-
axis flux
World first!
Detailed information in differential cross section (in muon kinematics)
T2K preliminary
T2K Cross Section 2018 Highlights
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CC0π on water, antineutrinos, off-
axis flux
World first!
Detailed information in differential cross section (in muon kinematics)
T2K preliminary
Test of oxygen model and uncertainties
comparison to latest theory for antineutrinos
T2K Cross Section 2018 Highlights
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T2K preliminary
CC inclusive, multiple targets neutrinos, on-
axis flux
Update
FHC ⌫µ Flux (A.U.)
CC-Total
CC-RES
CC-QE+2p2h
NEUT 5.3.6, �⌫µchMINERvA: L.E.
NOvA: O↵ axis
T2K: On axis
T2K: O↵ axisSK: Oscillated
Best Fit [1707.01048]
0
0.5
1
1.5
2
�(E
⌫)/E
⌫(103
8cm
2nu
cleon�1GeV
�1)
0 1 2 3 4 5E⌫ (GeV)
T2K Cross Section 2018 Highlights
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T2K preliminary
CC inclusive, multiple targets neutrinos, on-
axis flux
Update
FHC ⌫µ Flux (A.U.)
CC-Total
CC-RES
CC-QE+2p2h
NEUT 5.3.6, �⌫µchMINERvA: L.E.
NOvA: O↵ axis
T2K: On axis
T2K: O↵ axisSK: Oscillated
Best Fit [1707.01048]
0
0.5
1
1.5
2
�(E
⌫)/E
⌫(103
8cm
2nu
cleon�1GeV
�1)
0 1 2 3 4 5E⌫ (GeV)
Test of T2K’s model and uncertainties
against a new energy spectra
T2K Cross Section 2019 Highlights
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Limited acceptance CC antineutrino on
water and CH, 1.5 deg axis flux and new
detector (WAGASCI)
New energy spectra
T2K Cross Section 2019 Highlights
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Limited acceptance CC antineutrino on
water and CH, 1.5 deg axis flux and new
detector (WAGASCI)
New energy spectra
0-5º5-10º
10-15º15-20º
20-25º25-30º
T2K preliminary
T2K Cross Section 2019 Highlights
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Limited acceptance CC antineutrino on
water and CH, 1.5 deg axis flux and new
detector (WAGASCI)
New energy spectra
0-5º5-10º
10-15º15-20º
20-25º25-30º
T2K preliminary
Test of T2K’s model and uncertainties
against a third! energy spectra
T2K Cross Section 2019 Highlights
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Limited acceptance CC antineutrino on
water and CH, 1.5 deg axis flux and new
detector (WAGASCI)
New energy spectra
0-5º5-10º
10-15º15-20º
20-25º25-30º
T2K preliminary
Test of T2K’s model and uncertainties
against a third! energy spectra
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T2K Cross Section 2019 Highlights
W"
νµ""
N"N’"
Δ"π"
CCπ"" µ�""
Background for oscillation analyses - signal for exotic searches
CC1π+ per nucleon, off-axis flux neutrinos
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T2K Cross Section 2019 Highlights
CC1π+ per nucleon, off-axis flux neutrinos
Update
Additional projections not
shown
T2K preliminary
W"
νµ""
N"N’"
Δ"π"
CCπ"" µ�""
Background for oscillation analyses - signal for exotic searches
29
T2K Cross Section 2019 HighlightsUpdate
Additional projections not
shown
T2K preliminary
W"
νµ""
N"N’"
Δ"π"
CCπ"" µ�""
Background for oscillation analyses - signal for exotic searches
Test of new resonance model and
uncertainties
CC1π+ per nucleon, off-axis flux neutrinos
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NC1𝞬, off-axis flux neutrinos
T2K Cross Section 2019 Highlights
Background for appearance searches
New!
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New!
J.Phys. G46 (2019) no.8, 08LT01
T2K Cross Section 2019 Highlights
NC1𝞬, off-axis flux neutrinos
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New!
J.Phys. G46 (2019) no.8, 08LT01
T2K Cross Section 2019 Highlights
NC1𝞬, off-axis flux neutrinos
Challenges of understanding small
backgrounds
T2K Cross Section 2019 Highlights
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CC0π on CH, off-axis flux neutrinos and
antineutrinos
Combined analysis
• Difference in sign of neutrino and antineutrino cross section is axial-vector interference term
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Additional bins, projections not shown T2K preliminary
CC0π on CH, off-axis flux neutrinos and
antineutrinos
Combined analysis
• Difference in sign of neutrino and antineutrino cross section is axial-vector interference term
Asymmetry
T2K Cross Section 2019 Highlights
35
Additional bins, projections not shown T2K preliminary
CC0π on CH, off-axis flux neutrinos and
antineutrinos
Combined analysis
• Difference in sign of neutrino and antineutrino cross section is axial-vector interference term
Asymmetry
T2K Cross Section 2019 Highlights
Probe of neutrino - antineutrino differences
for uncertain processes (QE+2p2h)
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Far detector too!
• NC-QE-like scattering is a background to relic SN neutrino searches; can be a signal for dark matter searches
• Identified using nuclear de-excitation photons
T2K Cross Section 2019 Highlights
[GeV]νE0 0.5 1 1.5 2 2.5 3
]2 c
m-3
8 1
0× [
NC
QE
σ
0
0.5
1
1.5
2
2.5
3
T2K Neutrino Data (Run1-9)
NEUT
NEUT Flux-averaged
Flux (Run1-9)νT2K FHC
37
T2K Cross Section 2019 Highlights
T2K preliminary
Far detector too!
• NC-QE-like scattering is a background to relic SN neutrino searches; can be a signal for dark matter searches
• Identified using nuclear de-excitation photons
[GeV]νE0 0.5 1 1.5 2 2.5 3
]2 c
m-3
8 1
0× [
NC
QE
σ
00.20.40.60.8
11.21.41.61.8
2
T2K Antineutrino Data (Run1-9)
NEUT
NEUT Flux-averaged
Flux (Run1-9)νT2K RHC
T2K preliminary
First antineutrino!
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Single pion productionDedicated single pion selection is also limited in angular range
T2K PRELIMINARY
Significant experimental data disagreement: [PRD92, 092008 (2015), AR article: arxiv.1803.08848]
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Future of T2K: ND upgrade
• Improved acceptance as compared to ND280 - improved cross section measurements
• Robust modelling of neutrino-nucleus interaction models are critical to a variety of physics experiments
• Many different communities contribute to improved modelling: electron scattering data, neutrino scattering data, theory groups, and simulation developers
Summary
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• Robust modelling of neutrino-nucleus interaction models are critical to a variety of physics experiments
• Many different communities contribute to improved modelling: electron scattering data, neutrino scattering data, theory groups, and simulation developers
Summary
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provides valuable measurements of neutrino interactions to test and improve models.
• More details (including flux, signal definition, and data here: http://t2k-experiment.org/publications/)
Thank you for your attention!
Backup
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Model Progress on T2KDominant uncertainty in oscillation analysis from neutrino
interaction (cross section) model
Error source1-ring e-like
ν-mode ν-mode_
νe/νe_
SK Detector 2.83 3.79 1.47SK FSI+SI+PN 3.02 2.31 1.58
Flux + Xsec constrained 3.02 2.86 2.31
Eb 7.26 3.66 3.74
σ(νe)/σ(νμ) 2.63 1.46 3.03
NC1γ 1.07 2.58 1.49
NC Other 0.14 0.33 0.18
All Systematics 8.81 7.03 5.87