T2K ND280 cross section results and future prospects · T2K ND280 cross section results and future...

1

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

2

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


X

i


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


X

i


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


X

i


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

7

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"

8


E⌫ (GeV)0 1 2 3 4 5

�(E

⌫)/E

⌫(103

8cm

2nu

cleon�1GeV

�1)

0

0.5

1

1.5

2


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)

9


E⌫ (GeV)0 1 2 3 4 5

�(E

⌫)/E

⌫(103

8cm

2nu

cleon�1GeV

�1)

0

0.5

1

1.5

2


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

10


• Well-understood beam: recently improved flux uncertainties (esp. data from NA61 and soon EMPHATIC); neutrino and antineutrino-modes

T2K Preliminary

11

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

12

Global program requires multiple measurements





• T2K near detectors have multiple targets: C, H2O, Fe and Ar, Pb

Interaction in ND280 TPC’s gas (predominantly Ar)

https://www.google.com/search?client=firefox-b-1-d&q=predominantly&spell=1&sa=X&ved=0ahUKEwjc4-26uuvkAhWDA4gKHTrpBuUQkeECCC0oAA

13

Global program requires multiple measurements dσ/dQ2 vs. Eν: QE, single nucleon

(McFarland, Ruterbories)





E⌫(GeV)Ann. Rev. Nucl. Part. Sci. 68, 105 (2018)

14

Global program requires multiple measurements dσ/dQ2 vs. Eν: QE, single nucleon

(McFarland, Ruterbories)





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)

15

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

16

• 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

17

• 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

18

CC0π on water, antineutrinos, off-

axis flux

World first!

muonNeutrino

T2K preliminary

Detailed information in differential cross section (in muon kinematics)


19


axis flux

World first!


T2K preliminary


20


axis flux

World first!


T2K preliminary

Test of oxygen model and uncertainties

comparison to latest theory for antineutrinos


21

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)


22

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


23

Limited acceptance CC antineutrino on

water and CH, 1.5 deg axis flux and new

detector (WAGASCI)

New energy spectra


24



detector (WAGASCI)

New energy spectra

0-5º5-10º

10-15º15-20º

20-25º25-30º

T2K preliminary


25



detector (WAGASCI)

New energy spectra

0-5º5-10º

10-15º15-20º

20-25º25-30º

T2K preliminary


against a third! energy spectra


26



detector (WAGASCI)

New energy spectra

0-5º5-10º

10-15º15-20º

20-25º25-30º

T2K preliminary


against a third! energy spectra

27


W"

νµ""

N"N’"

Δ"π"

CCπ"" µ�""

Background for oscillation analyses - signal for exotic searches

CC1π+ per nucleon, off-axis flux neutrinos

28



Update

Additional projections not

shown

T2K preliminary

W"

νµ""

N"N’"

Δ"π"

CCπ"" µ�""


29

T2K Cross Section 2019 HighlightsUpdate

Additional projections not

shown

T2K preliminary

W"

νµ""

N"N’"

Δ"π"

CCπ"" µ�""


Test of new resonance model and

uncertainties


30

NC1𝞬, off-axis flux neutrinos


Background for appearance searches

New!

31

New!

J.Phys. G46 (2019) no.8, 08LT01



32

New!

J.Phys. G46 (2019) no.8, 08LT01



Challenges of understanding small

backgrounds


33

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

34

Additional bins, projections not shown T2K preliminary


antineutrinos

Combined analysis


Asymmetry


35

Additional bins, projections not shown T2K preliminary


antineutrinos

Combined analysis


Asymmetry


Probe of neutrino - antineutrino differences

for uncertain processes (QE+2p2h)

36

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

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 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!

38

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]

39

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

40

• 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

41

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!

http://t2k-experiment.org/publications/

Backup

42

43

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

T2K ND280 cross section results and future prospects · T2K ND280 cross section results and future...

Documents

Transcript of T2K ND280 cross section results and future prospects · T2K ND280 cross section results and future...