Hall-C Coincidence Hall-C Coincidence Commissioning Experiments Commissioning Experiments

E12-10-104 & E12-10-003E12-10-104 & E12-10-003Krishna Adhikari

Mississippi State University

1Joint Hall-A & Hall-C Summer meeting (July 17-18, 2015)

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E12-10-104: Theoretical MotivationE12-10-104: Theoretical Motivation

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Hadron Propagation & TransparencyHadron Propagation & Transparency

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• Measurement of proton and pion transparencies will provide an understanding of the propagation of highly energetic particles through the nuclear matter.

• The A(e,e’p) process will provide valuable information on the interpretation of the rise in transparency found in the BNL A(p,2p) experiments. This is true even if these experiments do not find a rise in transparency in the Q2 range covered. There is large overlap with the beam momentum range of the BNL experiment.

• The A(e,e’π+ ) process can map the region in Q2 from the onset of CT to ~10 GeV2, where such effects validate the strict applicability of factorization theorems for meson electro-production experiments.

Hadron Propagation & TransparencyHadron Propagation & Transparency

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• Hadron propagation through the nuclear medium is a key element of the nuclear many body problem.

• Understanding hadron propagation is important for the interpretation of many phenomena and experiments, and remains an active area of interest. – N. C. R. Makins et al. PRL 72, 1986 (1994) (cited 153 times)– G. Garino et al. PRC 45, 780 (1992) (cited 88 times)– D. Abbott et al. PRL 80, 5072 (1998) (cited 88 times)– K. Garrow et al. PRC 66, 044613 (2002) (cited 92 times)

• At high energies the main process is reduction of flux, which is called Nuclear Transparency.

• Nuclear transparency can also be used to search of signature of QCD in Nuclei.

Nuclear TransparencyNuclear Transparency

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Nuclear TransparencyNuclear Transparency

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For light nuclei very precise calculations are possible.

Nuclear TransparencyNuclear Transparency

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Color Transparency: a color coherence Color Transparency: a color coherence property of QCDproperty of QCD

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Color Transparency: a color coherence Color Transparency: a color coherence property of QCDproperty of QCD

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First direct search for color transparencyFirst direct search for color transparency

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Current Status of CT Current Status of CT (Search for the onset of CT )(Search for the onset of CT )

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A(e,e’p) @ 11 GeV JLabA(e,e’p) @ 11 GeV JLab

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E12-10-104: Hadron Propagation & Color E12-10-104: Hadron Propagation & Color Transparency at 12 GeVTransparency at 12 GeV

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Total beam time requested for A(e,e’p) is ~10 days (for 10 cm LH2)

Spokespersons: D. Dutta & R. Ent

E12-10-104: As a Commissioning Expt.E12-10-104: As a Commissioning Expt.

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E12-10-104: As a Commissioning Expt.E12-10-104: As a Commissioning Expt.

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• SHMS used as hadron arm (modest requirements)– A(e,e'p) needs p/π

separation– Singles rates < 10kHz– p/π ratio 1:1 - 1:2

• Targets needed: – 10 cm LH2

– thick and thin Carbon.

– 4 cm LH2 & multi-foil for commissioning spectrometer

SHMS & Target requirementsSHMS & Target requirements

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Commissioning Run PlanCommissioning Run Plan

Projected resultsProjected results

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Next ExperimentE12-10-003

Deuteron Electro-Disintegration at Very Deuteron Electro-Disintegration at Very High Missing Momenta (E12-10-003)High Missing Momenta (E12-10-003)

K. Aniol,1 A. Asaturyan,2 H. Baghdasaryan,3 F. Benmokhtar,4 H. Bitao,5 W.U. Boeglin (spokesperson),6 S. Danagoulian,7 D. Day,3 D. Gaskell,8 D. Higinbotham,8 G. Huber,9 S. Jeschonnek,10 X. Jiang,11 M. K. Jones (co-spokesperson),8 N. Kalantarians,3 C. Keppel,12 M. Kohl,12 P.E. Markowitz,6 A. Mkrtchyan,2 H. Mkrtchyan,2 E. Piasetzky,13 A. Puckett,11 B.A. Raue,6 J. Reinhold,6 G. Ron,13 M. Sargsian,6 R. Shneor,13 G. Smith,8 R. Subedi,3 V. Tadevosyan,2 J. W. Van Orden,14 F. R. Wesselmann,15 S. Wood,8 and S. Zhamkochyan2

(1)California State University L.A., (2) Yerevan Physics Institute, (3) University of Virginia, (4) Carnegie Mellon University, (5) Lanzhou University, (6) Florida International University, (7)North Carolina A&T State University, (8) Jefferson Lab, () 9University of Regina, (10) Ohio State University, (11) Los Alamos National Laboratory, (12) Hampton University, (13) Tel-Aviv University, (14) Old Dominion University, (15) Xavier University of Louisiana

D(e,e’p)n with the neutron missing mass and angle reconstructed

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Previous Hall A experiment (E01-020)Previous Hall A experiment (E01-020)

• Data taken for d(e,e’p)n reaction with cut on neutron reconstructed missing mass at Q2 = 3.25 GeV2.

Published in PRL 107, 262501

• Top plot is ratio of measured cross section to the predicted PWIA cross section versus nq for 3 bins of missing momentum: pm = 200,400 and 500 MeV/co pm = 200 data has dip at nq = 70-80o o pm = 400 and 500 show peak at nq= 70-80o due to

large FSI with larger FSI for high pm

o All pm bins have small FSI at nq = 40o±10

• Bottom plot is the reduced cross section plotted versus pm for bins of nq = 35o±5 (blue points) and nq = 75o±5 (red points)

• In the PWIA , the reduced cross section maps the deuteron wave function. The lines are PWIA calculations using the CD Bonn and Argonne V18 deuteron wave functions.

• nq = 75o±5 shows large FSI for pm > 350• nq = 35o±5 data is in good agreement with PWIA

calculations and indicate that measurements at these kinematics will be sensitive to deuteron wave function.

• Would like data at higher missing momentum!

200400

Pm = 500

Large FSIPm dependent

nq = 75o

nq = 35o

The experiment will: Determine cross sections at missing momenta above 0.5 GeV/c Measure at well defined kinematic settings at Q2 = 4.25

– Selected kinematics to minimize contributions from FSI– Selected kinematics to minimize effects of delta excitation

Motivation:– Explore a new kinematical region of the 2-nucleon system above pm> 500– No Deuteron data exist at these kinematics!– Short range correlation studies cover similar region on missing momenta– DIS at high Q2 and small x and J/ production are sensitive to Deuteron

wave function at small distances– Models are able to reproduce the present data.

Experimental Goals Experimental Goals

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Experimental SetupExperimental Setup

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Beam: Energy: 11 GeVCurrent: 80A

Electron arm Electron arm fixedfixed at: at:SHMSSHMS at pcen = 9.32 GeV/ce = 11.68o Q2 = 4.25 (GeV/c)2

x = 1.35 nq = 40o

Vary proton arm to measure:Vary proton arm to measure:HMS 1.96 ≤ pcen ≤ 2.3 geV/cAngles: 63.5o ≥ p ≥ 53.1pm = 0.5, 0.65, 0.8 GeV/c

HMS

SH

MS

Kinematics and Beam TimeKinematics and Beam Time

I. pm = 0.5 (GeV/c), beam time 8 hoursII. pm = 0.65 (GeV/c), beam time 18 hoursIII. pm = 0.8 (GeV/c), beam time 36 hours

Beam: Energy: 11 GeVCurrent: 80A

Electron arm fixed at:SHMS at pcen = 9.32 GeV/ce = 11.68o Q2 = 4.25 (GeV/c)2

x = 1.35 nq = 40o

Vary proton arm to measure :pm = 0.5, 0.65, 0.8 GeV/cHMS 1.96 ≤ pcen ≤ 2.3 geV/cAngles: 63.5o ≥ p ≥ 53.1

Detect electron and proton and reconstruct missing mass of neutron.

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Expected Results

Total beam time : 62 Hours

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SummarySummary• Two coincidence commissioning experiments for Hall-C• E12-10-104: E12-10-104: A(e,e’p) data to study high energy proton

propagation in nuclear matter (nuclear transparency) and color transparency (CT)

• E12-10-003: E12-10-003: New Deuteron data in unknown kinematic territory

• Modest requirement on precision• PID:

e/ separation with Cherenkov and calorimeter p identification with coincidence timing

• Data can be produced while performing spectrometer commissioning

• Experience gained during this experiment will help laterexperiments that require higher precision 27

Thank you!!!

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