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Inclusive Scattering from Nuclei at x>1 and High Q2 with a 5.75 GeV Beam

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Constraints on the high momentum tail of the nuclear wave function ... Experimental Setup in Hall C. SOS. HMS. High Momentum Spectrometer ... – PowerPoint PPT presentation

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Title: Inclusive Scattering from Nuclei at x>1 and High Q2 with a 5.75 GeV Beam


1
Inclusive Scattering from Nuclei at xgt1 and High
Q2 with a 5.75 GeV Beam
  • Nadia Fomin
  • University of Virginia

2
Physics topics we can study at xgt1
  • Momentum distributions of nucleons inside nuclei
  • Short range correlations (the NN force)
  • ?3-Nucleon correlations
  • ?Comparison of heavy nuclei to LD2 and 3He
  • Scaling (x, y) at large Q2
  • Constraints on the high momentum tail of the
    nuclear wave function
  • Structure Function Q2 dependence

3
Quasielastic scattering an example (Deuterium)
4
Electron scattering and x ranges
  • Scattering from a free nucleon 0ltxlt1
  • x1 (elastic)
  • xlt1 (inelastic)
  • x gt 1
  • ?momentum is shared between nucleons, so 0ltxltA
  • ? probing the effect of nuclear medium on quark
    distributions
  • ? kinematics determine whether the electron
    scatters from quarks or hadrons
  • Regions being probed
  • ? Low Q2 entire nucleus (elastic)
  • ? Intermediate Q2 single nucleon (Quasielastic
    Scattering QES)
  • ? Higher Q2 DIS (superfast quarks at xgt1)
  • xgt1 probes the QES and DIS regions

5
Y-scaling
  • Introduced by Kawazoe and West in 1975
  • Scaling function F(y) can be extracted from the
    measured cross-section if QES is the dominant
    reaction mechanism
  • F(y) is defined as ratio of the measured
    cross-section to the off-shell electron-nucleon
    cross-section times a kinematic factor
  • At large q, neglecting momenta perpendicular to q
    and using energy conservation
  • In general, FF(y,Q2), but the Q2 dependence
    vanishes at high momentum transfer
  • n(k) is the nucleon momentum distribution
  • Scaling breaks down if there are significant
    Final State Interactions between the struck
    nucleon and the residual nucleus, but this
    should also vanish at sufficiently high Q2

6
Y-Scaling (Example 3He)
y is the momentum of the struck nucleon parallel
to the momentum transfer.
0.1ltQ2lt3.9
7
E02-019 Details
  • E02-019 is currently running at Jefferson Lab in
    Hall C
  • E02-019 is an extension of E89-008, but with
    higher E (5.75 GeV), Q2 , x and y.
  • Cryogenic Targets LH2, LD2, 3He, 4He
  • Solid Targets C, Cu, Au.
  • Spectrometers HMS and SOS

8
Experimental Setup in Hall C
HMS
SOS
9
High Momentum Spectrometer
  • Superconducting magnets in a QQQD configuration
  • Maximum central momentum of 6.0 GeV/c with 0.1
    resolution and a momentum bite of 10
  • Solid angle of 6.7 msr
  • Detectors
  • 2 sets of Drift chambers
  • 2 sets of x-y hodoscopes
  • Gas Cerenkov detector
  • Lead glass shower counter
  • Pion Rejection of 75,000 using the Cerenkov and
    the Lead Glass Shower Counter

10
Short Orbit Spectrometer
  • For E02-019, the SOS is primarily used to
    estimate the charge symmetric background.
  • Has a solid angle of 7 msr and a large momentum
    bite (20)
  • Maximum central momentum of 1.75 GeV/c
  • QDD magnet configuration (non-superconducting)
  • Pion Rejection of 10,000 using the Cerenkov and
    the Lead Glass Shower Counter
  • Detector Package is very similar to that of HMS

11
New Frontiers
Existing data
12
3He online spectrum
13
Summary
  • To date, weve taken over 60 of the data
  • This experiment will provide data over an
    extended kinematic range and significantly
    improve the 3He and 4He data sets
  • Preliminary results should be ready by next
    years DNP meeting (see you in Hawaii)

14
E02-019 Collaboration
  • Argonne National Lab
  • California Institute of Technology
  • Hampton University
  • Thomas Jefferson National Accelerator Facility
  • University of Basel (Roman Trojer)
  • University of Virginia

15
New Frontiers
Existing data
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