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Neutrino Scattering Physics withthe Fermilab Proton Driver

Introductory Overview

Conveners:Jorge G. Morfín (Fermilab)

Ron Ransome (Rutgers)Rex Tayloe (Indiana)

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A bit of history… 1930-Wolfgang Pauli Dear Radioactive Ladies and Gentlemen….

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Milestones in the History of Neutrino Physics

1934 - Enrico Fermi develops a comprehensive theory of radioactive decays, including Pauli's hypothetical particle, which Fermi coins the neutrino (Italian: "little neutral one").

1959 - Discovery of a particle fitting the expected characteristics of the neutrino is announced by Clyde Cowan and Fred Reines.

1962 - Experiment at Brookhaven National Laboratory discovered a second type of neutrino ()

1968 - The first experiment to detect e produced by the Sun's burning (using a liquid Chlorine target deep underground) reports that less than half the expected neutrinos are observed.

1985 - The IMB experiment observes fewer atmospheric interactions than expected. 1989 - Kamiokande becomes the second experiment to detect e from the Sun finding only about 1/3

the expected rate. 1994 - Kamiokande finds that travelling the greatest distances from the point of production to the

detector exhibit the greatest depletion. 1997 - Super-Kamiokande reports a deficit of cosmic-ray and solar e, at rates agreeing with earlier

experiments. 1998 - The Super-Kamiokande collaboration announces evidence of non-zero neutrino mass at the

Neutrino '98 conference. 2000 - First direct evidence for the announced at Fermilab by DONUT collaboration. 2004 - APS Multi-divisional Neutrino Study. 2005 - MiniBooNe announces result - yes/no/maybe LSND correct, MINOS starts data-taking.

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What are the Open Questions in Neutrino PhysicsFrom the APS Multi-Divisional Study on the Physics of Neutrinos

What are the masses of the neutrinos? What is the pattern of mixing among the different types of neutrinos? Are neutrinos their own antiparticles? Do neutrinos violate the symmetry CP? Are there “sterile” neutrinos? Do neutrinos have unexpected or exotic properties? What can neutrinos tell us about the models of new physics beyond the Standard Model?

The answer to almost every one of these questions involves understanding how neutrinos interact with matter!

Among the APS study assumptions about the current and future program:

“determination of the neutrino reaction and production cross sections required for a precise understanding of neutrino-oscillation physics and the neutrino astronomy of astrophysical and cosmological sources. Our broad and exacting program of neutrino physics is built upon precise knowledge of how neutrinos interact with matter.”

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Outline of the Study of Neutrino Scattering Physics

What motivates further study of neutrino scattering physics? EPP needs - future Wednesday talk NP needs - future Wednesday talk

What will we know by the start of a Fermilab Proton Driver (FPD)? Snapshot of expected experimental results at FPD start-up

What can best/only be done with the FPD? Is there anything left to do and reason to do it?

What tools do we need to do it? “Designer” beams Specialized detectors

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What’s actually happening in Neutrino-Nucleus Scattering

N / qHNucleus/nucleon/quark NC / CC

We don’t know incoming neutrino energy. We don’t know, a priori, if it interacts with nucleus, nucleon or

quark. For CC event, we infer incoming neutrino energy from measured

final-state energy. Since T is small (order 10-(38-40) cm2) need intense neutrino beams

and/or massive target/detectors. Using a massive target/detectors masks details of the final state

including the energy. We need an intense neutrino beam so we can gather significant

statistics with a fine-grained, low-A target/detector to see details.

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In spite of (because of) the experimental challenges, Neutrino Scattering Physics at FPD brings together several communities

EPP - motivated by increased understanding of physics relevant to neutrino oscillation experiments, properties of the neutrino and structure of nucleon

NP - motivated by understanding of physics complementary to the Jlab program (form factors, structure of nucleon)

Neutrinos from 8 GeV ProtonsLimited scope of physics topics

Minimize backgrounds from higher energies

Specialized study of verylow-energy phenomena

Neutrinos from 120 GeV ProtonsExtended scope of physics topics

to cover quasi-elastic to DIS

Must understand/study “backgrounds”

Neutrino energies similar to JLab

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Motivation: EPP - Neutrino Oscillation requirements Future Wednesday talk for details

e appearance needs: Coherent pion cross sections

» Robust predictions from CC and NC processes

High y cross sections If signal is seen, we really need QE and resonance cross sections much better than we have now Control neutrino/anti-neutrino systematics at 1 percent level for

mass hierarchy and CP studies.

High Statistics disappearance needs: Measurements of Nuclear effects in neutrinos “neutrino energy calibration” Ratio of Quasi-elastic to non-Quasi-elastic cross sections

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Motivation: Nuclear Physics Interest - Ron Ransome Future Wednesday talk for details

Significant overlap with JLab physics for 1-10 GeV neutrinos

Four major topics:

Nucleon Form Factors - particularly the axial vector FF

Duality - transition from resonance to DIS (non-perturbative to perturbative QCD)

Parton Distribution Functions - particularly high-xBJ

Generalized Parton Distributions - multi-dimensional description of partons within the nucleon

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Neutrino Scattering Topics

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

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

Nuclear Effects Spin-dependent parton distribution functions Generalized Parton Distributions

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State of our Knowledge at start of FPD - Time SnapshotAssume following experiments complete…

K2K - 12 GeV protons

MiniBooNE - 8 GeV protons

MINERA (Running parasitically to MINOS) - 120 GeV protons

HARP, BNL E910, MIPP (E907) - Associated experiments to help flux determination

Jlab - High precision elastic scattering to help QE analysis

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

FINeSSE

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Completed experiments by FPD-time

Main physics channels: quasi-elastic, resonant and coherent 1- production

May also have a reasonable sample of the above channels

Main physics channels:quasi-elastic, Resonant and coherent 1-, and low-W, multi- channels

E (GeV)

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MINERAMI -120 GeV Protons

C, Fe and PbNuclear targets

Move target only

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 DIS 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

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(Quasi)-elastic Scattering

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 SciBar (80% purity)

Current status

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Neutrino Scattering: 8 GeV Proton Driver - Rex Tayloe Future Wednesday talk for details

- NC elastic scattering - A measurement of NC elastic scattering is sensitive to axial, isoscalar

component of proton (strange quark contribution to proton spin, s) - Ratio of NC/CC reduces systematics - proton driver would enable this measurement with - and perhaps (with high intensity) measurement on nucleon targets (H/D)

allowing elimination of nuclear structure errors.

- e elastic scattering - sensitive to magnetic moment => new physics - measured by low-Ee recoil energy behavior - rates are low! Require highest-intensity beam.

FINeSSE could give us a first look at these topics

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MINERA CC Quasi-Elastic MeasurementsFully simulated analysis, including realistic detector simulation and reconstruction

We will understand - nucleus elastic scattering by the time of FPD.Except for possible MiniBooNe, low E sample, we will NOT

have elastic -nucleus and certainly not / - nucleon as well

Average: eff. = 74 % and purity = 77%

Expected MiniBooNE and K2K measurements

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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

We will understand coherentscattering well by the time of FPD.

Except for a possible MiniBooNelow E sample, we will NOT havemeasured - coherent scattering.

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Parton Distribution FunctionsCTEQ uncertainties in u and d quark fits

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DIS: Parton Distribution Functions Ability of to taste different quarks allows isolation of flavors

At high x

F2p - xF3

p = 4xu

No messy nuclear corrections!

F2p + xF3

p = 4xu

- Proton Scattering

EPP and NP interest in PDFsNeed and p/n target

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Nuclear Effects - studied only with charged leptons

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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Difference between and nuclear effectsSergey Kulagin

Need significant statistics tofully understand nuclear effects

with the weak current

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What will we need beyond MiniBooNE, K2K and MINERA for neutrino scattering at FPD?

HIGH-STATISTICS ANTINEUTRINO EXPOSURE Need to improve purity of beam?

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

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

IMPROVED DETECTOR TECHNIQUES Particularly good neutron detection for Need a fully-active detector for H2 and D2 exposures

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Need a Very Efficient Beam

Low energy NuMI ‘”””’ beam yields around

1.1 events

for every event!

Resulting beam is almost pure beam: in mode = 4 x 10-3

Loose factor five in intensity compared to NuMI + factor 3.5 compared to

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Need a large H2/D2 target

An efficient fully-active CCD coupled tracking detectorBubble Chamber

A Chicago - Fermilab collaboration developing Contemporary large BC design/construction/operation

Techniques including CCD readout

H_2/D_2BC Placed in the upstream

part of MINERA

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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 exclusive cross-sections, form factors and nuclear effects.

We will need the FPD, with both an 8 GeV (proton) and 120 GeV (proton) neutrino program, to have similarly reasonable results for: -nucleus cross-sections, and - proton and neutron (D2) cross-sections,

- e elastic scattering high-statistics narrow-band studies of NC (and CC) channels.

There is considerable work to be done in detailing the neutrino scattering program at the FPD. Your participation is most welcome.