Progress in Neutrino-Nuclear Scattering!much ado about ν-A things

Kendall Mahn!Michigan State University

Image from recent workshop on neutrino scattering (NuInt2014)

OutlineTheoretical status Results from MINERvA

What is neutrino scattering?!Why is neutrino nuclear (ν-A) scattering important to oscillation expt’s?!

What is the current state of knowledge about ν-A?

Future experiments

Results from MicroBooNE

2

Talks in this session:

• Charged Current Quasi Elastic (CCQE) and multinucleon processes (2p2h)

Energy transfer!figure from Ref 1

3

Processes in Neutrino Scattering!merely players

W"

2p2h

νµ"

N’,N’"N,"N"

µ�"

"

W"

CCQE

νµ"

N’"N"

µ�"

"

Observable

neutrino (anti)

• muon or electron (+)

• proton (neutron)

Energy transfer!figure from Ref 1

4

Processes in Neutrino Scattering!merely players

• Production of pions, CC1π+/0/- and NC1π+/0/-

W"

νµ""

N"N’"

Δ"π"

CCπ"" µ�""

resonant coherent W"

νµ""

A"

π+"

CCπ"" µ�""

A"

(GeV)νE0 1 2 3 4 5 6

flux

(arb

.)µν

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8T2K off-axis flux

T2K on-axis flux

MiniBooNE flux

A near detector fluxνNO

A fluxνMINER

• Neutrinos probe the V-A nature of the weak interaction

• But, neutrino decay-in-flight beams are not mono-energetic

• Spread of beam is larger than nuclear effects 5

Neutrino Sources and Nuclear Effects!

[Ref 2]

DUNE ~1-10 GeV

• Multiple processes contribute to each observable topology

• CCQE-like observable topology: muon, proton, no pions

• Includes true CCQE, 2p2h, CC1π (pion absorbed in nucleus)

6

Nuclear Effects Example!

W"

CCQE

νµ"

N’"N"

µ�"

"

W"

2p2h

νµ"

N’,N’"N,"N"

µ�"

"

W"

νµ""

N"N’"

Δ"π"

CCπ"" µ�""

• Oscillation depends on energy

• Estimate from hadronic and/or leptonic information

EQE� =

m2p �m�2

n �m2µ + 2m�

nEµ

2(m�n � Eµ + pµ cos �µ)

Why is ν-A important for oscillation expts?!

E⌫

= Eµ

+X

Ehadronic

(GeV)true - EQErecoE

-1 -0.5 0 0.5

Arb

itra

ry U

nit

sCCQE

5)×Nieves multinucleon (

5)×-decay (∆pionless

• Nuclear effects bias true and estimated neutrino energy

muon

hadronic

Neutrino

[Ref 3]

8

• Even with a near detector, critical reliance on model !

• 2p2h feed-down to oscillation peak from [Ref 4]

(GeV)νE0 0.5 1 1.5 2

νFl

ux*E

0

20

40

60

80

100

120

140310×

Multinucleon Feed-down on Oscillated Flux

(GeV)νE0 0.5 1 1.5 2

νFl

ux*E

0

200

400

600

800

1000910×

Multinucleon Feed-down, ND280 Flux

Why is ν-A important for oscillation expts?!

Far detector!Eν - EνQE smearing for Eν=0.8 GeV

Near detector !Eν - EνQE smearing for Eν=0.8 GeV

ND(⌫µ) = �(E⌫)⇥ �(E⌫ , A)⇥ ✏ND

FD(⌫µ) = �(E⌫)⇥ �(E⌫ , A)⇥ ✏FD ⇥ P (⌫µ ! ⌫e)

• Current and future long and short baseline oscillation rely on modeling of neutrino interaction physics even with near detectors. Need:

• Predicted signal, background efficiency, energy estimate for

• Muon and electron neutrinos, and antineutrinos

• But, outstanding QE, 1π puzzles indicate our understanding is incomplete

Path forward: test modern models for processes of interest with a variety of experimental probes

9

Summary of ν-A issues!there is nothing either good or bad, but

thinking makes it so

• Unprecedented experimental information! ArgoNEUT, MicroBooNE, MINERvA, NOvA, T2K

• Range of beam energies, target materials, with neutrinos and antineutrino sources

• Coming soon: new information from neutrons (ANNIE, CAPTAIN)

• Impressive model development in neutrino interaction software programs (GENIE [Ref 5], GiBUU, NEUT, NuWro)

• New alliance between theorists and experimentalists (NuSTEC)

• Next School will be in October 2017

• Subscribe nustec-news@fnal.gov (see backup)

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Recent Progress, Effort in ν-A !The undiscovered country

See posters on interaction

models

• CCQE-like process important for T2K, NOvA, DUNE, Hyper-K, SBL programs

• “QE puzzle”: MiniBooNE results at odds with higher energy measurements, single nucleon models

• New T2K analysis consistent between MiniBooNE: higher QE-like cross section suggestive of presence of nuclear effects, including 2p2h processes

(GeV)νE0 1 2 3 4 5 6

/ nu

cleo

n)2

cm-3

8 (1

0σ

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

NEUT v5.1.4.2

T2K flux (arb units)

MiniBooNE flux (arb units)

MiniBooNE T2K Full T2K Restricted0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

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New T2K CCQE-like results!

W"

CCQE

νµ"

N’"N"

µ�"

"

W"

2p2h

νµ"

N’,N’"N,"N"

µ�"

"

(GeV)µ

True p0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

nucl

eon

GeV2

cm

-38

10 θ

dpdc

osσ2 d

0

0.2

0.4

0.6

0.8

1

1.2

< 0.80µθ0.70 < true cos < 0.80µθ0.70 < true cos• Detailed information (cross section in muon kinematics) [Ref 6] compared to latest QE and 2p2h models!

• Different energy beams is important, as no complete model yet: !

• MINERvA (higher energy) differential measurement of muon, proton

• ArgoNeuT proton multiplicity

• Antineutrino beams provide complementary information

12

New T2K CCQE-like results!

(GeV)µ

True p0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

nucl

eon

GeV2

cm

-38

10 θ

dpdc

osσ2 d

0

0.2

0.4

0.6

0.8

1

1.2

< 0.80µθ0.70 < true cos < 0.80µθ0.70 < true cos

(GeV)µ

True p0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4

nucl

eon

GeV2

cm

-38

10 θ

dpdc

osσ2 d

00.10.20.30.40.50.60.70.80.9

1 < 0.00µθ-1.00 < true cos

Data: shape uncertaintyFlux normalization uncertaintyMartini et alNieves et al

Analysis I

< 0.00µθ-1.00 < true cos

(GeV)µ

True p0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4

nucl

eon

GeV2

cm

-38

10 θ

dpdc

osσ2 d

00.10.20.30.40.50.60.70.80.9

1 < 0.00µθ-1.00 < true cos

Data: shape uncertaintyFlux normalization uncertaintyMartini et alNieves et al

Analysis I

< 0.00µθ-1.00 < true cos (GeV)µ

True p0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4

nucl

eon

GeV2

cm

-38

10 θ

dpdc

osσ2 d

00.10.20.30.40.50.60.70.80.9

1 < 0.00µθ-1.00 < true cos

Data: shape uncertaintyFlux normalization uncertaintyMartini et al (w/o 2p2h)Martini et al

Analysis I

< 0.00µθ-1.00 < true cos

• CC inclusive selection, use estimate of available energy from all charged particle tracks (proton, pion, muon) [Ref 7]

• 2p2h model not “enough”: new experimental way to test model13

Novel MINERvA Test of Nuclear Effects!

Similar analysis soon

from NOvA

• Important background (and signal) process for oscillation (non-standard) physics

• Challenge to reconcile low energy and MiniBooNE and higher energy MINERvA data

• NOMAD also sees disagreements in production of backward going pions

• Challenge to reconcile pion and muon kinematics within same model for MiniBooNE

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Single Pion Production Puzzles!a madness most discreet

Brand new MINERvA update

[Ref 8]

W"

νµ""

N"N’"

Δ"π"

CCπ"" µ�""

!

• T2K pion production predominantly from delta

• Pion production on T2K mostly from Δ resonance

• First differential measurement on water [Ref 9]

• T2K carbon, water measurements consistent: 2σ lower than GENIE prediction

15

New T2K CCπ+ results on water!

• Observation of coherent ν-C scattering from MINERvA [Ref 10]

• New T2K measurements

off-axis: 2.2σ excess over background, consistent with and lower than current models [Ref 11]

on-axis: 1.7σ excess over background, suppression at high pion angle like MINERvA [Ref 12] 16

Coherent Pion Production!Success!

Detection and modeling of rare

process

T2K preliminary

• New measurement from NOvA for νe interactions on scintillator (carbon) [Ref 13]

• Measurement also from MINERvA [Ref 14]: Sets scale of different νe/νμ nuclear effects of <15-30% 17

Electron Neutrino Interactions!

• NCπ0 is a background to νe appearance searches

• Challenge to reconcile MiniBooNE NC and CC π0/+ production within same model

• Evidence for NC diffractive π0 seen by MINERvA [Ref 15]

• Proof-of-concept LAr NCπ0 measurement from ArgoNeuT [Ref 16]

18

Neutral Current Measurements!

MicroBooNE, NOvA soon!

• Flux changes across on-axis T2K detector due to off-axis effect

• Compare nearby detectors to infer cross section using known flux properties

• Results [Ref 17] on iron target consistent with NEUT, GENIE

(GeV)E0 1 2 3 4

p.o.

t.)21

/50M

eV/1

02

Flux

(/cm

0

0.5

1

1.5

1210!

Module 3Module 2Module 1Module 0

!

" #

$%&'()*+%,

-*./

!

!"

# $%

& '!"

!!

(

!'

!"

)

!&

(GeV)νE0 1 2 3 4 5 6 7

/nucl

eon)

2 (

cmσ

0

10

20

30

40

50-3910×

p.o

.t.)

21

/50

MeV

/10

2 f

lux

(/c

mµ

ν

0

500

1000

1500

910×

MINOSNEUTGENIENEUT flux averageGENIE flux average

T2K INGRID

T2K INGRID flux ave.

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Novel T2K CC Inclusive Results!

• Nuclear effects in neutrino interactions are important for the current and future oscillation physics program: all depend on model

• New measurements from current experiments (ArgoNeuT, MINERvA NOvA and T2K) facing current puzzles in QE, 1π physics

• Complementary datasets at different beam energies being compared to the modern models; novel experimental techniques

• Coherent picture emerging in CC coherent pion scattering

• New measurements of νe interactions, new information for NC

• MicroBooNE coming online, and new information soon on neutron yields from neutrino interactions (ANNIE, CAPTAIN)

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Summary !O brave ν world, that has such people in't!

Thank you to the organizers for the invitation!

Please check out the wealth of posters on neutrino cross sections!

Special thanks:

L. Fields (MINERvA) J. Paley, M. Muther (NOvA) S. Bolognesi, C. Wilkinson (T2K)

References can be found in backup slides

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Backup slides

22

References1. B Foris, and C N Papanicolas, Electron Scattering and Nuclear Structure

http://www.annualreviews.org/doi/pdf/10.1146/annurev.ns.37.120187.001025

2. Fluxes from:

1. T2K off-axis: official, http://t2k-experiment.org/publications/the-t2k-neutrino-flux-prediction/

2. T2K on-axis: not official, digitized from http://arxiv.org/abs/1509.06940

3. MINERvA: not official, from this analysis http://arxiv.org/pdf/1406.6415v3.pdf

4. NOvA: not official, digitized from https://arxiv.org/abs/1511.00287 Fig 3

3. Plot from T2K: Phys. Rev. Lett. 112, 181801 (2014) http://arxiv.org/abs/1403.1532

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References4. NuPRISM LOI; http://arxiv.org/abs/1412.3086

5. New GENIE v.2.10 manual: http://arxiv.org/pdf/1510.05494v1.pdf

6. T2K CC0π, accepted by PRD, http://arxiv.org/abs/1602.03652

7. MINERvA nuclear effects, Phys. Rev. Lett. 116, 071802 (2016), https://arxiv.org/abs/1511.05944. Plot from NuINT talk.

8. MINERvA CC1π+, Phys.Rev. D92, 092008 (2015). https://arxiv.org/pdf/1406.6415v3.pdf

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References9. T2K CC1π+ on water, submitted to PRD, http://arxiv.org/abs/1605.07964

10. MINERvA CC coherent pion prod, Phys. Rev.Lett. 113, 261802 (2014). http://arxiv.org/abs/1409.3835

11.T2K ND280 CC coherent pion: http://arxiv.org/pdf/1604.04406v1.pdf, submitted to PRD

12.T2K INGRID CC coherent pion: plot from NuInt2015 talk: http://indico.ipmu.jp/indico/getFile.py/access?contribId=34&sessionId=7&resId=0&materialId=slides&confId=46

13.NOvA νe: Wine and Cheese FNAL seminar: http://theory.fnal.gov/jetp/talks/nova_20160226.pdf

14.MINERvA νe: Phys. Rev. Lett 116, 081802 (2016) http://arxiv.org/abs/1509.05729

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References!

15. MINERvA diffractive π0, submitted to PRL; https://arxiv.org/abs/1604.01728

16.ArgoNEUT NCπ0 http://arxiv.org/abs/1511.00941

17.T2K CC inclusive result: Phys. Rev. D 93, 072002 (2016), http://arxiv.org/abs/1509.06940

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27

Status of neutron measurements from neutrinos

• ANNIE: first measurements of abundance of final state neutrons from neutrino-oxygen interactions **ref

• Uses Gd doped water and Large Area Picosecond Photosensor Detectors

• Currently making background measurements

• CAPTAIN: measure response of LAr detectors to neutrons, rate of n from nu-Ar

• Mini-CAPTAIN: operating in neutron beam

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