Clear example of Bridging Physics between Jlab and MINERva at Fermilab

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-------Quasielastic Scattering in MINERvA
------- A. Bodek, H. Budd - Rochester will get
Steve Manly -Rochester and Tony Man -Tufts
also involved

• Clear example of Bridging Physics between Jlab
  and MINERva at Fermilab
• Physics
• Quasielastic cross sections for neutrino
  oscillations - Dominated by low Q2, Axial Mass,
  Pauli exclusion, low Q2 modification of form
  factors in nuclear medium, Nuclear Effects/Final
  state interactions and Identification of the
  quasielastic channel, misidentification of
  resonances as quasielastic etc. (important for
  JHF to SuperK)
• Measurement of axial form factor at high Q2. Is
  it the dipole form, or another form - a new line
  of investigation only possible by the high
  statistics and precision of Minerva
• For both, need to do a comparison of electron and
  neutrino scattering - (S. Manly - electron
  scattering Jlab Hall B CLAS data - e.g. Final
  states in quasielastic).Also use electron data to
  extrapolate Carbon to Oxygen and cancel as well
  as understand, nuclear effects.

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JHF region 0.7 GeV
FNAL region 3 GeV
JHF region 0.7 GeV
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FNAL region 3 GeV
JHF region 0.7 GeV
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• We are currently investigating
• Effect of Pauli suppression with Bodek/Ritchie
  High momentum tail
• Use more sophisticated spectral functions for
  nuclear effects
• Need to study effect of off-shell definitions of
  form factors
• Effect of suggested modifications of form factors
  inside nucleus
• Strickman says that form factor modification may
  be true at low Q2 but not true for Q2 gt. 1 GeV2
  (as indicated by Jlab data).
• Investigate how the neutrino experiments select
  quasielastic events (is it in the experiment)
• Need to measure both Q2 distribution and Cross
  sections

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Start with Quasielastic C.H. Llewellyn Smith
(SLAC).Phys.Rept.3261,1972
Updated recently By Bodek, Budd and Arrington 2003
Vector
Axial
Vector form factors From electron scattering Via
CVC
Vector
Neutrino experiments use Dipole form factors
with Gen0 -Because this is what was put in the
LS paper (not exactly correct)
Axial form factor from Neutrino experiments
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Budd, Bodek, Arrington BBA-2003 Form Factor Fits
to SLAC/JLAB data. Vector Nucleon form factors
display deviations from dipole. Controversy on
Gep high Q2
What does axial form factor Fa do between 1 and 3
GeV2 ????
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K2K Near detector data on Water was Fit with
wrong Vector Form factors. New BBA2003 form
factors and updated M_A have a significant effect
on Neutrino oscillations Results.
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Updating Neutrino Axial Form Factors--gt Use new
BBA-2003 Precise Vector Form Factors as input to
neutrino data. With BBA-2003 Form Factors, Axial
Vector M_A1.00. However, no information on Axial
form factor for Q2gt1 GeV2. Future Very High
Statistics neutrino data will be available on
Carbon. Need precise vector form factors, as
modified in Carbon (including effect of
experimental cuts) Can measure F_A(Q2)/
GM_V(Q2) at High Q2 - By combining Jlab and
MINERvA data
Quasielastic Old Bubble Chamber Data on D2.
(Steve Manly was A member of this
collaboration (as a PhD Thesis student)
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Measure F_A(Q2)/GM_V(Q2) by comparing
neutrino And electron e-e-p data on Carbon with
1 Million events
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Precise measurement of Axial Form factor of the
Nucleon can only be done using a combined
analysis (with the same cuts) of a sample of
e-e-p data from electron scattering at Jlab (on
Carbon) with the Corresponding n - m- p data
from neutrino scattering On Carbon and using same
cuts (on final state proton etc). (measure F_A
at high Q2 for first time). Since future high
statistics neutrino data will only be done with
nuclear targets (e.g. scintillator), Nuclear
Effects can both be studied, as well as cancelled
by performing a combined analysis of these two
data sets. Collaborate with a parallel program in
Hall B (Manly) Produce well understood DSTs of
e-e X on Carbon that can be used in a combined
analysis with neutrino data. Start with
quasielastic, and continue on to resonances, and
DIS. In the process, also do physics such as
nuclear transparency, modification of resonance
and DIS final states in nuclei, etc.
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F_A/FA_Dipole (M_a1.0) from Q20 to Q23
(normalized to 1 at Q20. BBA03 get best fit
Ma1.0 GeV2)
What does axial form factor Fa do between 0 and 3
GeV2 ????
Dipole Ma1.1 Ma1.0 is line at 1.0 Sehgal
prediction Dipole Ma0.9
Lalit Sehgal 1979 EPS Conference on High Energy
Physics in Geneva (Proc,Vol.1,p.98,published
by CERN). F_A / G_MV should be taken to be the
ratio of the A_1 and rho poles (not
dipoles), G_MV itself being taken from electron
scattering.Explicitly, F_A/G_M(1-q2/M_rho2)/(
1-q2/M_A12), where M_rho0.77GeV,M_A1sqrt(2)M_
rhoGeV.
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F_A/F_A_Dipole (M_a1.0) from Q20 to Q23
(normalized)
What does axial form factor Ga do between 0 and 3
GeV2 ????
Dipole Ma1.2 Ma1.0 is 1.0 Sehgal
prediction Dipole Ma0.8
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• Q2lt0.3 Region, Interest
• Determine Maradius of axial proton
• Compare to Ma from pion electroproduction
• Determine quaielastic cross section where most
  of the events are - for neutrino oscillation in
  the 1 GeV region , e.g. K2K,JHF MiniBoone.
• Sensitive to both Pauli Exclusion and final
  state ID if a nuclear target is used, e.g.
  Carbon, Water. Lose Quasielastic events, or
  misID resonance events. -gt - Need to use Jlab
  Hall B data on D2, C and Fe - Manly Analysis
  proposal
• Low recoil proton momentum PSqrt(Q2)

• Q2 gt 1 GeV2 Region, Interest
• Determine deviations from Dipole form factors is
  it like Gep or Gmp .
• Not sensitive to Paul Exclusion, but sensitive to
  final state ID. -gt - Need to use Jlab Hall B data
  on D2, C and Fe - Manly analysis proposal
• Higher recoil proton momentum PSqrt(Q2)

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Back of envelope estimates - needs to be done
more quantitatively
0.5 GeV P 15 cm of scintillator 120 MeV
energy Versus 1 mip 2 MeV/cm. Get 60
mips
For Q20.110 GeV2, q3P0.330 GeV Proton kinetic
energy P2/2M 55 MeV Range about 5 cm -
Note nuclear binding about 30 MeV
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Note all particles at a given angle must have
energies lower than a quasielastic muon
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Case of magnetized Steel MINERVA B-H Curve for
steel can be found at http//www-fmi.fnal.gov/fmii
nternal/MI_Notes_Pages/MI-0127.pdf which has been
backed up to http//www.pas.rochester.edu/bodek
/minerva/MI-0127.pdf Table 3 page 12 for Armco
steel show that for H10, B10 Kgauss (B1 T, or
mu-1000). Pretty much around 1000 for lower H.
However to get to saturated iron is hard. For
H30, B-15 and for H-60 B20.5. So need a factor
of 6 more current to go from B10 Kgauss to B20
Kgauss (below H10 it is linear). Scaling from
CCFR, which has B1.6 T and L4.8 meter and
resolution of 10. One gets momentum resolution
(which will only be used for sign) of Sigma
(16/ B(Tesla) Sqrt 4.8/L(meters) Pt
kick 2.4 GeV/c (B/1.6 T) (L meter/4.8m) so
for 1.2 iron at 1 T we get sigma of 16 times 2
or 32. (PT KICK OF 0.44 GeV) Factor of 2
Better if we use 2 T (see below) which requires
factor of 10 more current Energy resolution from
range is just how well you can determine range
(the more scintillator sampling, the better range
is determined). What kind of current do we
need. Lab E has 4 coils. 12 turns 1200 amp each.
total NI48x1200 Amp Get 1.9 T at 1 foot and
1.55 T at the edge. 2.4 GeV Pt kick. However, it
does not have quality magnet iron steel. For a
square rod going around Minerva of L4x4 meter
so total path of magnetic field is 16 meters
(most outer Design, inner path is L248 meter
H 4Pi (10-3) N I /16 m in
Orested Need to get H above 10, so running with
48 coils at between 300 and 500 Amps gives B12
to 14 Kgauss (see spreadsheet).
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LTV Not optical
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Armco better
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Active target 2mx2m Picture frame. EM Cal 8
1.25 cm Fe plates followed by 8 1.25 cm
scintillators Had/Muon range detector 8
10 cm followed by 8 1.25 cm scintilltors Total
12,.5 cm Fe 80 Cm Fe 92.5 cm Fe and 16x
1.25 20 cm scintillator
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Armco Steel
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