1. Hall-C Coincidence Commissioning Experiments E12-10-104 & E12-10-003 Krishna Adhikari Mississippi State University 1 Joint Hall-A & Hall-C Summer meeting (July 17-18, 2015)

2. 2

3. E12-10-104: Theoretical Motivation 3

4. Hadron Propagation & Transparency 4 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 Q 2 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 Q 2 from the onset of CT to ~10 GeV 2, where such effects validate the strict applicability of factorization theorems for meson electro- production experiments.

5. Hadron Propagation & Transparency 5 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.

6. Nuclear Transparency 6

7. 7 For light nuclei very precise calculations are possible.

8. Nuclear Transparency 8

9. Color Transparency: a color coherence property of QCD 9

10. 10

11. First direct search for color transparency 11

12. Current Status of CT (Search for the onset of CT ) 12

13. A(e,e’p) @ 11 GeV JLab 13

14. E12-10-104: Hadron Propagation & Color Transparency at 12 GeV 14 Total beam time requested for A(e,e’p) is ~10 days (for 10 cm LH 2 ) Spokespersons: D. Dutta & R. Ent

15. E12-10-104: As a Commissioning Expt. 15

16. E12-10-104: As a Commissioning Expt. 16

17. 17 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 LH 2 –thick and thin Carbon. –4 cm LH 2 & multi-foil for commissioning spectrometer SHMS & Target requirements

18. 18 Commissioning Run Plan

19. Projected results 19

20. 20 Next Experiment E12-10-003

21. Deuteron Electro-Disintegration at Very 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. Zhamkochyan 2 ( 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 21

22. 22 Previous Hall A experiment (E01-020) Data taken for d(e,e’p)n reaction with cut on neutron reconstructed missing mass at Q 2 = 3.25 GeV 2. 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: p m = 200,400 and 500 MeV/c o p m = 200 data has dip at  nq = 70-80 o o p m = 400 and 500 show peak at  nq = 70-80 o due to large FSI with larger FSI for high p m o All p m bins have small FSI at  nq = 40 o ±10 Bottom plot is the reduced cross section plotted versus p m for bins of  nq = 35 o ±5 (blue points) and  nq = 75 o ±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 = 75 o ±5 shows large FSI for p m > 350  nq = 35 o ±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! 200 400 P m = 500 Large FSI P m dependent  nq = 75 o  nq = 35 o

23. The experiment will:  Determine cross sections at missing momenta above 0.5 GeV/c  Measure at well defined kinematic settings at Q 2 = 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 p m > 500 – No Deuteron data exist at these kinematics! – Short range correlation studies cover similar region on missing momenta – DIS at high Q 2 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 23

24. Experimental Setup 24 Beam: Energy: 11 GeV Current: 80  A Electron arm fixed at: SHMS SHMS at p cen = 9.32 GeV/c  e = 11.68 o Q 2 = 4.25 (GeV/c) 2 x = 1.35  nq = 40 o Vary proton arm to measure: HMS 1.96 ≤ p cen ≤ 2.3 geV/c Angles: 63.5 o ≥  p ≥ 53.1 p m = 0.5, 0.65, 0.8 GeV/c HMS SHMS

25. Kinematics and Beam Time I.p m = 0.5 (GeV/c), beam time 8 hours II.p m = 0.65 (GeV/c), beam time 18 hours III.p m = 0.8 (GeV/c), beam time 36 hours Beam: Energy: 11 GeV Current: 80  A Electron arm fixed at: SHMS at p cen = 9.32 GeV/c  e = 11.68 o Q 2 = 4.25 (GeV/c) 2 x = 1.35  nq = 40 o Vary proton arm to measure : p m = 0.5, 0.65, 0.8 GeV/c HMS 1.96 ≤ p cen ≤ 2.3 geV/c Angles: 63.5 o ≥  p ≥ 53.1 Detect electron and proton and reconstruct missing mass of neutron. 25

26. Expected Results Total beam time : 62 Hours 26

27. Summary 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 later experiments that require higher precision 27

28. Thank you!!! 28