“E07-006 at Hall A Collaboration” Tai Muangma E07-006 :Status Report Nucleon-Nucleon Short-Range...
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Transcript of “E07-006 at Hall A Collaboration” Tai Muangma E07-006 :Status Report Nucleon-Nucleon Short-Range...
“E07-006 at Hall A Collaboration”Tai Muangma
E07-006 :Status Report Nucleon-Nucleon Short-Range Correlation
(NN-SRC)on He4 target
Hall A Collaboration MeetingDecember 10, 2012
Navaphon Muangma (Tai)
“E07-006 at Hall A Collaboration”Tai Muangma
What is Nucleon-Nucleon Short Range Correlation (NN-SRC)?
the phenomena are when the wave functions of the two nucleons are strongly overlapping
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“E07-006 at Hall A Collaboration”Tai Muangma
WHY IS NN-SRC INTERESTING?
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“E07-006 at Hall A Collaboration”Tai Muangma
NN-SRC is interesting because …
The nuclear shell model can only predict 60% of the spectral function. Long range correlation can only provide a 20% contribution. The short range correlation is believed to contribute the remaining 20%.
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Target MassSP
ECTR
OSC
OPI
C ST
REN
GTH
L. Lapikas, Nucl. Phys. A553 (1993) 297.
“E07-006 at Hall A Collaboration”Tai Muangma
NN-SRC is interesting because …The measurement of
nucleon momentum distributions for various nuclei yields a similar high momentum tail. Along with the shell model, the existence of NN-SRC pairs within the nuclei is believed to explain this phenomenon.
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“E07-006 at Hall A Collaboration”Tai Muangma
NN-SRC is interesting because …
The study of the NN-SRCs within the nucleus also provides more insight into cold, dense nuclear matter such as that found in neutron stars.
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“E07-006 at Hall A Collaboration”Tai Muangma
WHAT HAS BEEN DONE?
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“E07-006 at Hall A Collaboration”Tai Muangma
Inclusive MeasurementCLAS A(e,e’) data
The observed scaling means that the electrons probe the high-momentum nucleons in the 2N-SRC phase, and the scaling factors determine the per-nucleon probability of the 2N-SRC phase in nuclei with A>3 relative to 3He
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K. Sh. Egiyan et al., Phys. Rev. C 68 (2003) 014313.
r(A,3He) = a2n(A)/a2n(3He)
x =Q2
2M>1.5
Q2 > 1.4 [GeV/c]2
“E07-006 at Hall A Collaboration”Tai Muangma
Result (e,e’) and (e,e’p) and (e,e’pN) from E01-015
80 +/- 5% single particles moving in an average potential 60 – 70% independent single
particle in a shell model potential 10 – 20% shell model long range
correlations 20 +/- 5% two-nucleon short-
range correlations 18% np pairs 1% pp pairs 1% nn pairs (from isospin symmetry)
Less than 1% multi-nucleon correlations
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“E07-006 at Hall A Collaboration”Tai Muangma
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Correlated Pair Fractions from 12C R. Subedi et al., Science 320 (2008) 1476.
“E07-006 at Hall A Collaboration”Tai Muangma
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OUR UNIQUE EXPERIMENT
“E07-006 at Hall A Collaboration”Tai Muangma
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Customized (e,e’pN) Measurement
A pair with “large” relativemomentum between the nucleons
and small center of mass momentum
Relative to the Fermi-sea level ~ 250 MeV/c
• High Q2 to minimize MEC (1/Q2) and FSI
• x>1 to suppress isobar contributions
“E07-006 at Hall A Collaboration”Tai Muangma
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Experiment E07-006 vs E01-015 Missing momentum 400 – 800 MeV/c Tensor to Repulsive
Core
E01-015 E07-006XB >1, Q2 = 2 [Gev/c]2 XB >1, Q2 = 2
[Gev/c]2
300 – 600 MeV/c 400 – 800 MeV/c
Tensor Force Tensor to Repulsive core
Target – 12C Target – 4He(Less FSI)
BigBite and HAND BigBite with MWDCsUpgraded HAND(new lead wall)
Pushing Limits of NN Potential– Long range attraction– Short range repulsion
“E07-006 at Hall A Collaboration”Tai Muangma
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E07-006: 4He(e,e’pN)pn SRC• 4He Target
– Dense Nuclear Matter– Mean Feild & Exact
Calculations• Pm from 400 – 800 MeV
3 Kinematic setting: 500,650 & 750 MeV/c This reduce to two kinematic
for (e,e’N_recoil) , BigBite is at 97 degree and 92 degree.
Pmiss [MeV/c]
“E07-006 at Hall A Collaboration”Tai Muangma
WHAT WE HAVE FROM OUR EXPERIMENT RUN-PERIOD?
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“E07-006 at Hall A Collaboration”Tai Muangma
Production dataProduction period March 15 - April 13, 2011
May 11-12, 2011
Beam 4.46 GeV
Current 4 uA
Target He4 20 cm loop
HRS, Left Arm (fixed): 20.3 deg, 3.6 GeV/c
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“E07-006 at Hall A Collaboration”Tai Muangma
Production dataKinematic Setting Right HRS BigBite Cumulative Charge
Kin 1 :(p_miss = 500 MeV/c)
33.5 deg, 1.38 GeV/c
Angle: 97 degCurrent: 518 A
1.6 C With 0.7 C has no major problems
Kin 2 :(p_miss = 650 MeV/c)
29.0 deg, 1.31 GeV/c
Angle: 97 degCurrent: 518 A
1.67 C
Kin 3:(p_miss = 750 MeV/c
24.5 deg, 1.196 GeV/c
Angle: 92 degCurrent: 518 A
2.98 C
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“E07-006 at Hall A Collaboration”Tai Muangma
CURRENT PROGRESS
“E07-006 at Hall A Collaboration”Tai Muangma
Current Progress
The Calibrations for both HRSs is finished.The Neutron detector calibration is finished.The BigBite spectrometer is currently
underway.
“E07-006 at Hall A Collaboration”Tai Muangma
Vertex Calibration
Vertex calibration with 13 carbon foils with 25 mm separation (300 mm total length)
Achieve the resolution of 2.5 to 3.9 mm
Show the possibility of using high density optic foils.
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Phi (rad)
“E07-006 at Hall A Collaboration”Tai Muangma
In-plane & out-of-plane angles Calibration
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Sieve Y (m)
“E07-006 at Hall A Collaboration”Tai Muangma
HRSs from Production
Electron PID With the loose cut on Left-
HRS acceptance (dp, theta, phi, vertex), we can see the clear separation of the electron from pion.
Cut: dE/p = 0.6 5% pion was in the data.
“E07-006 at Hall A Collaboration”Tai Muangma
BigBite Detector
Coincident time with LHRS Resolution = 1.4 ns
“E07-006 at Hall A Collaboration”Tai Muangma
BigBite Detector
Proton PID dE vs E after calibration After calibration of the dE
& E scintillator planes, we can see a separation of the protons, deuterons and Minimum Ionized Particles.
However, it cannot separate proton from deuterons at high momentum.
“E07-006 at Hall A Collaboration”Tai Muangma
BigBite Detector
Calibration Momentum Initial calibration of the
reconstructed momentum from MWDC against|q3m| from elastics H(e,e’p) at three kinematic (350,400,450) MeV/c.
The resolution is at 7.7 MeV/c which is about 1.9 to 2.2 %
“E07-006 at Hall A Collaboration”Tai Muangma
BigBite Detector
Production PID 1 Production PID 2
“E07-006 at Hall A Collaboration”Tai Muangma
HRSs from Production
Coincidence time of HRSs The coincidence time for
the two HRSs after calibration achieve the resolution of 0.6 ns. This is mainly in the triple analysis.
“E07-006 at Hall A Collaboration”Tai Muangma
Neutron Detector Calibration
“E07-006 at Hall A Collaboration”Tai Muangma
Neutron Efficiency
“E07-006 at Hall A Collaboration”Tai Muangma
Neutron TOF for Production Pmiss = 750 MeV/c
“E07-006 at Hall A Collaboration”Tai Muangma
Neutron DetectorThe angular correlation between the initial proton and the recoil neutron. The clear back to back angular correlation of the short range np - pair can be seen.
Cosine of the opening angle between the proton and the neutron. Black: Signal + Background, Blue: Background estimated by event mixing, Red: Background from “off time”.
“E07-006 at Hall A Collaboration”Tai Muangma
PRELIMINARY RESULTS
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“E07-006 at Hall A Collaboration”Tai Muangma
Two Aimed Results 1. The triple coincident result:
Ratio (e,e’pp)/(e,e’p) Ratio (e,e’pn)/(e,e’p) Ratio (e,e’pp)/(e,e’pn)
2. the double coincident with backward (recoiled) nucleon. Absolute cross-section
(e,e’N_recoiled) Ratio
(e,e’p_recoiled)/(e,e’n_recoiled)
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“E07-006 at Hall A Collaboration”Tai Muangma
Preliminary Triple Coincident
The P_miss distribution of each kinematic. 34
“E07-006 at Hall A Collaboration”Tai Muangma
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• Spokespersons:• Shalev Gilad (MIT)• Douglas Higinbotham (JLab)• Eli Piasetzky (Tel Aviv)• Vincent Sulkosky (MIT)• John Watson (Kent State)
• Postdocs:• Aidan Kelleher (MIT)• Charles Hanretty (Uva)• Ran Shneor (Tel Aviv)
• Graduate Students:• David Anez (Saint Mary’s)• Or Chen (Tel Aviv)• Igor Korover (Tel Aviv)• Navaphon (Tai) Muangma (MIT)• Larry Selvy (Kent State)• Zhihong Ye (Uva)
Acknowledgements
“E07-006 at Hall A Collaboration”Tai Muangma
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“E07-006 at Hall A Collaboration”Tai Muangma
The END
Follow our analysis at http://hallaweb.jlab.org/
experiment/E07-006/analysis_page.html
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