Neutrino Scattering Physics with

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Neutrino Scattering Physics with the 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
  (nm).
• 1968 - The first experiment to detect ne 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 nm interactions than expected.
• 1989 - Kamiokande becomes the second experiment
  to detect ne from the Sun finding only about 1/3
  the expected rate.
• 1994 - Kamiokande finds that nm 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 nm and solar ne, 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 nt
  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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Whats actually happening in Neutrino-Nucleus
Scattering

• A / N / q gt
  n / m H
• Nucleus/nucleon/quark NC / CC

• We dont know incoming neutrino energy.
• We dont 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 sT 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 Protons Limited scope of
physics topics Minimize backgrounds from higher
energies Specialized study of very low-energy
phenomena
Neutrinos from 120 GeV Protons Extended 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

• ne appearance needs
• Coherent pion cross sections
• Robust predictions from CC and NC processes
• High y nm 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 nm 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
• sT , 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
• MINERnA (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-p production May also have a
reasonable n sample of the above channels
Main physics channels quasi-elastic, Resonant
and coherent 1-p, and low-W, multi- p channels
En (GeV)
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MINERnAMI -120 GeV Protons
Move target only
C, Fe and Pb Nuclear targets

• Main Physics Topics with Expected Produced
  Statistics
• Quasi-elastic 300 K events off 3 tons CH
• Resonance Production 600 K total, 450 K 1p
• Coherent Pion Production 25 K CC / 12.5 K NC
• Nuclear Effects C0.6M, Fe 1M and Pb 1 M
• DIS and Structure Functions 2.8 M total /1.2 M
  DIS event
• Strange and Charm Particle Production gt 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 GnE measurements

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, Ds)
- Ratio of NC/CC reduces systematics - proton
driver would enable this measurement with n
- and perhaps (with high intensity) measurement
on nucleon targets (H/D) allowing elimination of
nuclear structure errors.
- n e elastic scattering - sensitive to n
magnetic moment gt 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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MINER?A CC Quasi-Elastic MeasurementsFully
simulated analysis, including realistic detector
simulation and reconstruction
Average eff. 74 and purity 77
Expected MiniBooNE and K2K measurements
We will understand n - nucleus elastic scattering
by the time of FPD. Except for possible
MiniBooNe, low E sample, we will NOT have elastic
n -nucleus and certainly not n / n - nucleon
as well
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Coherent Pion Production

• Characterized by a small energy transfer to the
  nucleus, forward going p. NC (p0 production)
  significant background for nm --gt ne 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 En measurement
• Expect 25K events and roughly (30-40) detection
  efficiency with MINERnA.
• Can also study A-dependence with MINERnA

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MINERnA 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
Rein-Seghal
Paschos- Kartavtsev
We will understand n coherent scattering well by
the time of FPD. Except for a possible
MiniBooNe low E sample, we will NOT have measured
n - coherent scattering.
MINERnA
Expected MiniBooNE and K2K measurements
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Parton Distribution FunctionsCTEQ uncertainties
in u and d quark fits
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DIS Parton Distribution Functions Ability of n
to taste different quarks allows isolation of
flavors
n/ n - Proton Scattering
At high x
No messy nuclear corrections!
F2np - xF3np 4xu
F2np xF3np 4xu
EPP and NP interest in PDFs Need n and p/n target
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Nuclear Effects - studied only with charged
leptons
S. Kumano
Fermi motion
valence-quark
original EMC finding
antiquark
shadowing
x
sea quark
valence quark
EXPECTED to be different for n!!
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Difference between n-A and m-A nuclear
effectsSergey Kulagin
Need significant n statistics to fully understand
nuclear effects with the weak current
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What will we need beyond MiniBooNE, K2K and
MINERnA for neutrino scattering at FPD?

• HIGH-STATISTICS ANTINEUTRINO EXPOSURE
• Need to improve purity of n beam?
• HYDROGEN AND DEUTERIUM TARGET FOR n and n
• 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 n
• Need a fully-active detector for H2 and D2
  exposures

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Need a Very Efficient n Beam
Low energy NuMI n beam yields around 1.1 n
events for every n event!

• Resulting beam is almost pure n beam
• in n mode 4 x 10-3
• Loose factor five in intensity compared to NuMI
  factor 3.5 compared to n

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Need a large H2/D2 target
An efficient fully-active CCD coupled tracking
detector Bubble Chamber A Chicago - Fermilab
collaboration developing Contemporary large BC
design/construction/operation Techniques
including CCD readout
BC Placed in the upstream part of MINERnA
H_2/D_2
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Summary

• At the completion of MiniBooNE, K2K and the
  MINERnA 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
• n -nucleus cross-sections,
• n and n - proton and neutron (D2) cross-sections,
  
• n / n - 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.