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WG2 Summary - Part 2Neutrino Scattering Physics Topics

Conveners: Makoto Sakuda and Jorge G. Morfín

NuFact04 - Osaka, Japan

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Presentations and Discussions

Low energy neutrino interactions T. Sato (Osaka)Nuclear modification of valence quark distributions

and its effects on NuTeV sin^2 ? theta_W S. Kumano (Saga)DISCUSSION SESSION- WHAT IMPORTANT THEORETICAL QUESTIONS LEFT

TO ANSWER

MiniBOONE scattering results H.A. Tanaka (Princeton)K2K scattering results M. Hasegawa (Kyoto)MINERvA expected scattering results J.G. Morfin (FNAL)Tau production and decay via neutrino scattering K. Mawatari (Kobe)Study of strange quark in the nucleon with neutrino scattering T-A. Shibata (TIT)K2K NC pi0 production S. Nakayama (ICRR)HARP result I. Kato (Kyoto)BNL E910 result J. Link (Colombia)DISCUSSION SESSION - WHAT IMPORTANT NEUTRINO SCATTERING PHYSICS

QUESTIONS ARE UNANSWERED?

DISCUSSION SESSION - CAN SUPERBEAM OR NEUTRINO FACTORY ADDRESS THE OPEN QUESTIONS?

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Neutrino Oscillation: RequirementsDave Casper

Neutrino energy resolution for CC interactions K2K/T2K: Quasi-elastic channel MINOS/NOA: Calorimetry (Evis

E)

Understand Nuclear Effects Visible energy to neutrino energy

Control near/far beam flux and energy spectrum differences at few percent level

Control background for e appearance signature at few per-mille level Beam e, CC, NC contributions

Control neutrino/anti-neutrino systematics at 1 percent level for mass hierarchy and CP studies

C. Walter, NUINT02

K2K

NOA(13 nearCHOOZ bound)

NormalHierarchyInverted

Hierarchy

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Time SnapshotAssume following experiments complete…

K2K HARP, BNL E910 Jlab High precision elastic scattering

MiniBooNe HARP, BNL E910 Jlab High precision elastic scattering

MINERA (Running parasitically to MINOS)

HARP, BNL E910, MIPP (E907) Jlab High precision elastic scattering

T2K-I (no input as to scattering physics expectations)

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K2K Near Detectors

Extrudedscintillator(15t)

Multi-anodePMT (64ch)

Wave-lengthshifting fiber

EM calorim

eter

1.7m

3m3m

SciBar SciFi

E (GeV)

M. Hasegawa (Kyoto)

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MiniBooNE

H. Tanaka, (Princeton)

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Brief Introduction to the MINERA Experiment (Main INjector ExpeRiment -A)

A High-Statistics -Nucleus Scattering ExperimentUsing an On-Axis, Fine-grained Detector

in the NuMI Beam

Received Stage I Approval in April

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Both HEP and NP collaboratorsD. Drakoulakos, P. Stamoulis, G. Tzanakos, M. Zois

University of Athens, Athens, Greece

D. CasperUniversity of California, Irvine, California

E. PaschosUniversity of Dortmund, Dortmund, Germany

D. Boehnlein, D. A. Harris, M. Kostin, J.G. Morfin, P. Shanahan, P. Spentzouris

Fermi National Accelerator Laboratory, Batavia, Illinois

M.E. Christy, W. Hinton, C.E .KeppelHampton University, Hampton, Virginia

R. Burnstein, A. Chakravorty, O. Kamaev, N. SolomeyIllinois Institute of Technology, Chicago, Illinois

S.KulaginInstitute for Nuclear Research, Moscow, Russia

I. Niculescu. G. .NiculescuJames Madison University, Harrisonburg, Virginia

G. Blazey, M.A.C. Cummings, V. RykalinNorthern Illinois University, DeKalb, Illinois

W.K. Brooks, A. Bruell, R. Ent, D. Gaskell,,W. Melnitchouk, S. Wood

Jefferson Lab, Newport News, Virginia

S. Boyd, D. Naples, V. PaoloneUniversity of Pittsburgh, Pittsburgh, Pennsylvania

A. Bodek, H. Budd, J. Chvojka, P. de Babaro, S. Manly, K. McFarland, I.C. Park, W. Sakumoto, R. TengUniversity of Rochester, Rochester, New York

R. Gilman, C. Glasshausser, X. Jiang, G. Kumbartzki,K. McCormick, R. Ransome

Rutgers University, New Brunswick, New Jersey

H. Gallagher, T. Kafka, W.A. Mann, W. OliverTufts University, Medford, Massachusetts

J. NelsonWilliam and Mary College, Williamsburg, Virginia

Red = HEP, Blue = NP, Green = Theorist

Quantitative Study of Low-energy -Nucleus Interactions

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The MINERA Detector

Active target of scintillator bars (6t total, 3 - 5 t fiducial) - M64PMT Surrounded by calorimeters

upstream calorimeters are Pb, Fe targets (~1t each) magnetized side and downstream tracker/calorimeter

C, Fe and PbNuclear targets

OPTIONAL

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Location in NuMI Near Hall

MINERA preferred running is as close as possible to MINOS, (without Muon Ranger), using MINOS as high energy muon spectrometer If necessary, MINERA can run stand-alone elsewhere in the hall with the muon ranger

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The NuMI Neutrino Beam

Main injector: 120 GeV protons

110 m

1 km

Move target only

Move target andSecond horn

With E-907(MIPP) at Fermilab to measure particle spectra

from the NuMI target,expect to know neutrino flux to

≈ ± 3-4 %.

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MINERA will have the statistics to cover awide variety of important physics topics

Main Physics Topics with Expected Produced Statistics

Quasi-elastic 300 K events off 3 tons CH Resonance Production 600 K total, 450 K 1 Coherent Pion Production 25 K CC / 12.5 K NC Nuclear Effects C:0.6M, Fe: 1M and Pb: 1 M T and Structure Functions 2.8 M total /1.2 M DIS event Strange and Charm Particle Production > 60 K fully reconstructed events Generalized Parton Distributions (few K events?)

Assume 9x1020 POT: MINOS chooses 7.0x1020 in LE beam, 1.2x1020 in sME and 0.8x1020 in sHE

Event Rates per fiducial tonProcess CC NCQuasi-elastic 103 K 42 KResonance 196 K 70 KTransition 210 K 65 KDIS 420 K 125 KCoherent 8.4 K 4.2 KTOTAL 940 K 305 K

Typical Fiducial Volume = 3-5 tons CH, 0.6 ton C, ≈ 1 ton Fe

and ≈ 1 ton Pb

3 - 4.5 M events in CH0.5 M events in C1 M events in Fe1 M events in Pb

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After initial (parasitic to MINOS) run -could add a Liquid H2/D2(/O/Ar) Target

NOT APPROVED FOR THIS

H_2/D_2

MINOS Near

Fid. vol: r = 80 cm. l = 150 cm.

350 K CC events in LH2 800 K CC events in LD2

per year he- running. Few events with E ≈ 1 GeV.

Technically easy/inexpensive to build

and operate.

Meeting safety specifications the major

effort.

Planes of C, Fe, PbFor part of run

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Neutrino Scattering TopicsWhat will we know and not know at time snapshot?

Quasi-elastic Resonance Production - 1pi Resonance Production - npi, transition region - resonance to DIS Deep-Inelastic Scattering Coherent Pion Production Strange and Charm Particle Production Nuclear Effects T and Structure Functions

s(x) and c(x) High-x parton distribution functions

Spin-dependent parton distribution functions Generalized Parton Distributions

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(Quasi)-elastic

Dominant reaction up to ~1 GeV energy

Essential for E measurement in K2K/T2K

The “well-measured” reaction Uncertain to “only” 20% or so for

neutrinos Worse in important threshold region and

for anti-neutrinos

Axial form-factor not accessible to electron scattering Essential to modeling q2 distribution

Recoil proton reconstruction requires fine-grained design - impractical for oscillation detectors

Recent work focuses on non-dipole form-factors, non-zero Gn

E measurements

MiniBooNe

(88% purity)

K2K SciBar2-ring QE(70% purity)

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MINERA CC Quasi-Elastic Measurements

Fully simulated analysis, including realistic detector simulationand reconstruction

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CC Resonant Single-Pion Production

Existing data inconsistent (factor 2 variations)

Treatment of nuclear effects unclear Renewed theoretical interest

Rein - Sehgal used for decades

Sato-Uno-Lee Dynamical model gives a better fit to (poor) data

K2K S. Nakayama M. Hasegawa

MiniBooNe H. Tanaka:

0

0

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MINERA Resonance Production -

Total Cross-section and d/dQ2 for the ++ assuming 50% detection efficiencyErrors are statistical only

DO NOT FORGET RADIATIVE DECAYS AS BACKGROUND TO --> e

T

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Resonant Multi-pion Production andtransition to DIS - Quark/Hadron Duality

Recent JLAB data have revived interest in quark/hadron duality

Bodek and Yang have shown that DIS cross-sections can be extended into the resonance regime, and match the “average” of the resonant cross-section

We need more than just the “average” knowledge of the transition region - hills and valleys

Beyond kinematic range of K2K and MiniBooNe.

MINERA - 600K events Challenge to the resolution of

MINERA? Bodek and Yang

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DIS: Parton Distribution FunctionsWhat Can We Learn With All Six Structure Functions?

Does s = s and c = c over all x? If so.....

F 2Ν (x,Q2 ) =x u+ u + d+ d+2 s + 2c[ ]

F 2Ν (x,Q2 ) =x u+ u + d+ d+2s+ 2 c[ ]

xF 3Ν (x,Q2 ) =x u+ d - u - d - 2 s+ 2c[ ]

xF 3Ν (x,Q2 ) =x u+ d - u - d +2s - 2 c[ ]

F2 - xF3

=2 u + d+ 2 c( )=2U + 4 c

F2 - xF3

=2 u + d+ 2 s( )=2U + 4 s

xF3 - xF3

=2 s+ s( ) − c+ c( )[ ] =4 s - 4 c

Using Leading order expressions:

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Measuring Six Structure Functions for Maximal Information on PDF’s

d A

dxdQ2 = GF2

2x12

F 2A (x,Q2 ) + xF3

A (x,Q2 )( ) +1 −y( )2

2F 2

A (x,Q2 ) −xF 3A (x,Q2 )( )

⎡

⎣⎢⎤

⎦⎥

d A

dxdQ2 = GF2

2x12

F 2A (x,Q2 ) −xF 3

A (x,Q2 )( ) +1−y( )2

2F 2

A (x,Q2 ) + xF3A (x,Q2 )( )

⎡

⎣⎢⎤

⎦⎥

,x Q2 , (1− )y 2( )G2 2x

X = 0.1 - 0.125Q2 = 2 - 4 GeV2

Kinematic cuts in (1-y)not shown

+ y2 FL

(1-y)2

R = Rwhitlow

Neutrino1 year he-beam

Anti-Neutrino2 years he-beam

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Coherent Pion Production

0

N N

P

Z

Characterized by a small energy transfer to the nucleus, forward going . NC (0 production) significant background for --> .e oscillation search

Data has not been precise enough to discriminate between several very different models.

K2K, with their SciBar detector, and MiniBooNe will attempt to explicitly measure this channel - important low Emeasurement Expect 25K events and roughly (30-40)% detection efficiency with MINERA.

Can also study A-dependence with MINERA

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MINERA: Coherent Pion Production 25 K CC / 12.5 K NC events off C - 8.3 K CC/ 4.2 K NC off Fe and Pb

MINERA

Expected MiniBooNe and K2K measurements

Rein-Seghal

Paschos-Kartavtsev

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Nuclear Effects - Final state interactions

Include hadron formation length corrections

+

-

LH on

LH off

MINERA can measure LH off of C, Fe and Pb

E = 5 GeV

NEUGEN

+

K2K QE analysis

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Nuclear Effects - modified interaction probabilities

0.7

0.8

0.9

1

1.1

1.2

0.001 0.01 0.1 1

EMCNMCE139E665

shadowing

original

EMC finding

Fermi motion

x sea quark valence quark

EXPECTED to be different for !!

0.7

0.8

0.9

1

1.1

1.2

0.001 0.01 0.1 1

x

Ca

Q2 = 1 GeV2

valence-quark

0.4

0.6

0.8

1

1.2

1.4

0.001 0.01 0.1 1

x

antiquark

S. Kumano

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Nuclear Effects - Low low Q2 shadowing

Q2 distribution for SciBar detector

MiniBooNEFrom J. Raaf(NOON04)

All “known” nuclear effects taken into account:Pauli suppression, Fermi Motion, Final State Interactions

They have not included low- shadowing that is only allowed with axial-vector (Boris Kopeliovich at NuInt04)

Lc = 2 / (m2 + Q2) ≥ RA (not m

2) Lc

100 times shorter with mallowing low -low Q2 shadowing

ONLY MEASURABLE VIA NEUTRINO - NUCLEUS INTERACTIONS! MINERA WILL MEASURE THIS ACROSS A WIDE AND Q2 RANGE WITH C : Fe : Pb

Problem has existed for over two years

Larger than expected rollover at low Q2

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Low Q2 Suppression - alternative considerations M. Sakuda

List of items to be considered Is Coherent pion suppressed?

K2K will use PID to disentangle 1/coherent pion (Hasegawa) New data (e-N, C) on coherent pion production. CC from Mainz MAMI

Accelerator may tell us something.

Change in Elastic form factors Cause A few % effect on d/dq2 in lowq2 region

N form factor coupled with MA Sato (Nufact04), Paschos (NuInt04) Old Rein-Sehgal N form factor does not agee with data.

Uniform Fermi momentum distributions in MC? Electron scattering data show large kf component. Benhar(NuInt04) and

Nakamura (NuInt04). QE peak cross section 10-20% higher with Fermi Gas than with Spectral Functions which agrees better with electroproduction data,.

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What will we need beyond MiniBooNe, K2K and MINERA parasitic run for neutrino scattering?

ANTINEUTRINO EXPOSURE Need to improve purity - NuFact05 design efficient beam (with plug)

HYDROGEN AND DEUTERIUM EXPOSURE FOR and Need reasonable event rates at E ≈ 1 GEV

NARROW BAND BEAM FOR DETAILED LOOK AT NC? NuFact05 - Is off-axis beam sufficiently narrow?

IMPROVED DETECTOR TECHNIQUES PARTICULARLY GOOD NEUTRON DETECTION FOR

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What can Superbeams and Neutrino Factories Add to Scattering Measurements?

Debbie Harris

Neutral Current Measurements vs E

Anti-neutrino cross sections & interactions

H2, D2 Measurements

Polarized Target Measurements (spin structure functions)

Narrow Band Beams How narrow is narrow? Are there tricks to get more

narrow beams? Broad Band Beams

Largest rate No NC vs E available

Beta-beams Broad band, Low Energy

Neutrino Factories Broad Band Neutrino and antineutrino at the

same time, if you can reconstruct and e CC

NO NC vs E or even vs neutrino helicity!

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Summary

At the completion of MiniBooNe, K2K and the MINERA parasitic run we will have reasonable results for neutrino-nucleus interactions including cross-sections, form factors and nuclear effects.

We will need a SuperBeam to have similarly reasonable results for cross-sections, hydrogen and deuterium cross-sections for both and , high-statistics narrow-band studies of NC (and CC) channels.

We will need a Neutrino Factory for neutrino-polarized target experiments (T-A. Shibata) to understand the spin-dependent pdfs and generalized parton distributions.