Studying Nuclear Effects and Structure Functions at the NuMI Facility

1
Studying Nuclear Effects and Structure Functions
at the NuMI Facility

• Jorge G. Morfín
• Fermilab
• NuFact02
• London, July 2002

2
What are these Nuclear Effects?

• F2 / nucleon within a nucleus changes as a
  function of A.
• Nuclear effects measured (with high statistics)
  in ?-A not in ?.
• From low-to-high xBj go through shadowing,
  anti-shadowing, EMC effect, Fermi motion.

3
Are Nuclear Effects the SAME for n and e/m-A
Scattering

• Shadowing with n NOT the same as with charged
  leptons.
• Axial vector component of current
• Shadowing off valance quarks different than off
  sea quarks????
• Shadowing separate phenomena from nucleus, has to
  be put in by hand.
• All such IVB effects are contained in nuclear
  parton distribution functions (Kumano, Eskola et
  al.) for parton level interactions.
• EMC effect can be accounted for in nuclear
  spectral functions.

4
Any Indication of a Difference in Nuclear Effects
of Valence and Sea Quarks?

• Nuclear effects similar in Drell-Yan and DIS for
  x lt 0.1.
• Then no anti-shadowing in D-Ya while
  anti-shadowing seen in DIS (5-8 effect in
  NMC).
• Indication of difference in nuclear effects
  between valence sea quarks?
  a hep-ex/9906010

5
Nuclear Parton Distribution Functions

• This quantified by
• K.J. Eskolab et al within LO DGLAP using initial
  nuclear distributions from CTEQ4L and GRV-LO and
  assume scale evolution of nuclear parton
  densities is perturbative.
• S. Kumano et alc hep-ph/0103208 plus a talk at
  this workshop
• Neutrinos?have the ability to directly resolve
  flavor of the nucleons constituents
  ??interacts with d, s, u, and c while ??interacts
  with u, c, d and s.

b hep-ph/9807297 c hep-ph/0103208
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A Specific Look at ? Scattering Nuclear Effects

• S.A.Kulagin has calculated shadowing for F2
• and xF3 in ?-A interactions based on a
• non-perturbative parton model.
• Shadowing in the low Q2 (A/VMD dominance)
• region is much stronger than at higher Q2.

Q2 5 GeV2
7
? Scattering Nuclear Effects compared to e/m-A
Scattering
hep-ph/9812532
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Goals in Study of Nuclear Effectswith
?????scattering

• Overall Goal Measure nuclear effects across
  full xBj range in ?????scattering off a variety
  of targets.
• Goal Measure nuclear effects separately for F2
  and xF3. What are the nuclear effects for
  valence quarks alone ? Use as input to global
  nuclear PDFs
• Long-term Goal High statistics ????? scattering
  ?experiment on H2 and D2 as well as heavy nuclei
  to extract all six structure functions on
  nucleons as well as within nuclei.

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Fermilab On-site Beam and Near Detector Hall

• Target-Horn Chase 2 parabolic horns. 50 m
• Decay Region 1m radius decay pipe. 675 m
• Hadron Absorber Steel with Al core 5 m
• Muon range-out dolomite (rock). 240 m
• Near Detector Hall 45 m

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Neutrino Event Energy Distributions and
Statistics

• Reasonably expect 2.5 x 1020 pot per year of NuMI
  running.
• le-configuration Events- Epeak 3.0 GeV, ltEngt
  10.2 GeV, rate 200 K events/ton - year.
• me-configuration Events- Epeak 7.0 GeV, ltEngt
  8.5 GeV, rate 675 K events/ton - year pme
  rate 540 K events/ton - year.
• he-configuration Events- Epeak 12.0 GeV,
  ltEngt 13.5 GeV, rate 1575 K events/ton - year
  phe rate 1210 K events/ton - year.

With E-907 at Fermilab to measure
particle spectra from the NuMI target, expect to
know neutrino flux to 5.
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NuMI Near Hall Dimensions Geometry
Length 45m - Height 9.6m - Width 9.5m
Length Available for New Detector 26 m
Incoming angle n beam 58 mr
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NuMI Beam Interacts Off-Module-Center
Wonderful - inviting - spot for a new detector
which could use MINOS near detector as a muon
ID/spectrometer!
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Initial Step...
Scintillator Strips
Planes of C, Fe, Pb
MINOS Near
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Detector Conceptual Design

• 2m x 2 cm x 2cm scintillator (CH) strips with
  fiber readout.
• Fiducial volume r .8m L 1.5 3 tons of
  scintillator
• Downstream half pure scintillator
• Upstream half scintillator plus 2 cm thick
  planes of C, Fe and W.
• 11 planes C 1.0 ton (Scintillator)
• 3 planes Fe .95 ton (MINOS)
• 2 planes Pb .90 ton
• Readout combination of VLPC and multi-anode
  PMT.
• Use MINOS near detector as muon identifier /
  spectrometer.

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MINOS Parasitic Running Event Energy Distribution

• MINOS oscillation experiment uses mainly le beam
  with shorter pme and phe runs for control and
  minimization of systematics.
• An example of a running cycle would be
• 12 months le beam
• 3 months pme beam
• 1 month phe beam
• Assuming 2 such cycles (3 year run) with 2.5x1020
  protons/year 860 K events/ton. ltEngt 10.5
  GeV
• DIS (W gt 2 GeV, Q2 gt 1.0 GeV2) 0.36 M events
  / ton.
• Quasi elastic 0.14 M events / ton.
• Resonance Transition 0.36 M events / ton

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MINOS Parasitic Running x and Q2
Events / ton
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Prime User he Event Energy Distribution

• Run he beam configuration only! ltEngt 13.5 GeV
• For example, 1 year neutrino plus 2 years
  anti-neutrino would yield 1.6 M n -
  events/ton 0.9 M n - events/ton
• DIS (W gt 2 GeV, Q2 gt 1.0 GeV2) 0.80 M n
  events / ton 0.35 M n events / ton
• Shadowing region (x lt 0.1) 0.3 M events/ton

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he-beam x and Q2
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Add a Liquid H2/D2Target
Additional Tracking
Scintillator Strips
H_2/D_2
MINOS Near
Additional Tracking
Planes of C, Fe, Pb
Fiducial volume r 80 cm. and l 150 cm. 350
K CC events LH2 800 K CC events in LD2 per
year he-n running.
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Detector Event Rates

• Event rates (2.5 x 1020 protons per year)
• Parasitic Running Prime
  User Prime User
• (3 years) (1 year, he-n)
  (2 year, he -n)
• CH 2.60 M 4.80 M 2.70 M
• C 0.85 M 1.60 M 0.90 M
• Fe 0.80 M 1.55 M 0.85 M
• Pb 0.75 M 1.45 M 0.80 M
• LH2 0.35 M 0.20 M
• LD2 0.80 M 0.45 M

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Examples Expected Statistical Errors-MINOS
Parasitic(n running only)
Ratio Fe/C Statistical Errors xBj MINOS
2-cycle .01 - .02 1.3 .02 - .03 1.0
.03 - .04 0.9 .04 - .05
0.8 .05 - .06 0.8 .06 -
.07 0.7
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Examples Expected Statistical Errors - he Running
Ratios (he, 1 year n, DIS) Statistical Errors
xBj Fe/ LD2 Fe/C .01 - .02 11 9 .02 -
.03 6 5 .03 - .04 4 3 .04 - .05 3 2 .05 - .06 2
1.7 .06 - .07 1.7 1.4
Taking ratios beam systematics cancel. Assume
relative target systematics are the same as
Tevatron Muon Expt. O (1 ).
High xBj (he, 1 year, DIS) Statistical Errors
xBj CH LH2 LD2 .60 - .65 0.6 2 1.4
.65 - .70 0.7 3 1.7 .70 - .75 1.0
4 2 .75 - .80 1.3 5 3 .80 - .85
2 7 5 .85 - .90 3 11 7 .90
- .95 5 17 11 .95 - 1.0 7 25 16
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Fractional Statistical Errors in Measurements of
Fi Ratios

• Assuming he beam 1 year n and 2 year n
• One ton fiducial mass of C, Fe and Pb
• 0.5 ton fiducial mass of D2

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Six Structure Functions for Maximal Information
on PDFs
y2 FL
X 0.1 - 0.125 Q2 2 - 4 GeV2
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What Can We Learn With All Six Structure
Functions?
Leading order expressions

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

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Neutrino Factory Expected Errors on Measured Fs

• D2 Target r 50 cm l 60 cm.
• One year exposure.
• Errors on F1 better than 10
• Assume the Callan-Gross relationship eliminating
  F1.
• Errors now O (1) or better over most of the
  x-range.

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Summary

• Some nuclear effects are predicted to be
  different for n as compared to e/m scattering.
• Furthermore, Kulagin predicts nuclear effects
  different for valance as compared to sea quarks.
• We need to measure these nuclear effects as well
  as F2 and xF3 off different A targets to extract
  the nuclear parton distribution functions.
• NuMI Facility excellent for this purpose.
• The NuMI beam is Intense
• yielding 860 K events/ton during MINOS run
• yielding 1.6 M events/ton-year in the he_n
  -mode.
• NuMI Near Hall
• space for new detector(s) with w(x) 6 m, h(y)
  4 m,(sum) L 25 m.
• NuMI Near Hall Detector studies underway
• pure scintillator planes planes of A 3 - 5
  ton fiducial volume - cost O(3M)
• liquid H2 / D2 (bubble chamber) large target
  technically feasible - safety requirements..?
• With these detectors and a 1 year he_n and 2 year
  he_n exposure, we could measure the ratio (A/ D2)
  of F2 for x gt .01 to better than 10 and ratio of
  xF3 for x gt .02 to better than 30 (better than
  18 for x gt .02).