Exclusive study of Short range correlations

1. Hall C Summer Workshop Exclusive study of Short range correlations Eli Piasetzky Tel Aviv University, ISRAEL

2. Short /intermediate Range Correlations in nuclei A~1057 What SRC in nuclei can tell us about: High – Momentum Component of the Nuclear Wave Function. The Strong Short-Range Force Between Nucleons. tensor force, repulsive core, 3N forces Cold-Dense Nuclear Matter (from deuteron to neutron-stars). Nucleon structure modification in the medium ? EMC and SRC, contribution of non-nucleonic D.O.F to SRC 2N-SRC Nuclei are very dense chunk of matter BUT ~1 fm 1.f 1.7f 1.7 fm o = 0.16 GeV/fm3 Nucleons 12 GeV update

3. A triple – coincidence measurement EVA / BNL E01-015 / Jlab p p p n “Redefine” the problem in momentum space (E07-006) JLab / CLAS EG2

4. he A triple – coincidence measurement “Redefine” the problem in momentum space 3He

5. There are 18 ± 5 times more np-SRC than pp-SRC pairs in 12C. Why ? R. Subedi et al., Science 320, 1476 (2008). BNL / EVA 12C(e,e’pn) / 12C(e,e’p) [12C(e,e’pn) / 12C(e,e’pp)] / 2 [12C(e,e’pp) / 12C(e,e’p)] / 2

6. At 300-500 MeV/c there is an excess strength in the np momentum distribution due to the strong correlations induced by the tensor NN potential. pp/np 3He 3He np np pp pn pp V18 pp Bonn Schiavilla, Wiringa, Pieper, Carson, PRL 98,132501 (2007). 3He S=1 T=0 S=1 T=1 S=0 T=0 S=1 T=0 S=0 T=1 MeV MeV Ciofi and Alvioli PRL 100, 162503 (2008). Sargsian, Abrahamyan, Strikman, Frankfurt PR C71 044615 (2005). Argonne V8 potential

7. p Summary of Results CA 2010 γ n A(e,e‘p) 12C(p,2p n) Tang et al. PRL 042301 (2003) Long range (shell model) correlations Piasetzky, Sargsian, Frankfurt, Strikman, Watson PRL 162504(2006). 12 C 2N-SRC 60-70% 10-20% n-p pairs Single nucleons 20±5% 74-92 % 4.75±1% p-p pairs 2N-SRC 4.75±1% n-n pairs A(e,e‘pN) A(e,e‘) R. Subedi et al., Science 320, 1476 (2008). Egiyan et al. PRC 68, 014313. Egiyan et al. PRL. 96, 082501 (2006) Also data from SLAC and Hall C

8. Q>0 q=300-500 MeV/c pp/pn ratio as a function of pair CM momentum np pp q (fm-1) Q (fm-1) Wiringa, Schiavilla, Pieper, Carlson PRC 78 021001 (2008) Small Q  NN pair in s-wave  large tensor contribution  small pp/np ratio JLab / Hall B 300 < q < 500 MeV/c Hall A / BNL PRL 105, 222501(2010) Q pair CM momentum Q Q

9. Fe(e,e’pp) Pb(e,e’pp) Ein =5.014 GeV Q2=2 GeV/c2 X>1.2 JLab / CLAS Data Mining, EG2 data set, Or Chen et al.

10. 12C(e,e’pp) Ein =5.014 GeV Q2=2 GeV/c2 X>1.2 JLab / CLAS Data Mining, EG2 data set, Or Chen et al.

11. Directional correlation p γ p C(e,e’pp) Hall A data PRL 99(2007)072501 Hall B JLab / CLAS Data Mining, EG2 data set, Or Chen et al. PRELIMINARY Fe(e,e’pp) Pb(e,e’pp)

12. A new experiment Jan-May 2011 at JLab (E 07-006) Measurement over missing momentum range from 400 to 800 MeV/c. Taketani,Nakamura,Saaki Prog. Theor. Phys. 6 (1951) 581. (e,e’pp) / (e,e’pn) Chiral effective field Lattice QCD The data are expected to be sensitive to the NN tensor force and the NN short range repulsive force.

13. 12C(e,e’p) “300 MeV/c” “400 MeV/c” E01-015 Hall A 2005 “500 MeV/c” 4He(e,e’p) E07-006 Hall A 2011

14. 4He(e,e’p) E07-006 Hall A Jan- May 2011

15. Deep Inelastic Scattering (DIS) E E` Incident lepton scattered lepton (,q) W2 nucleon Final state Hadrons xB gives the fraction of nucleon momentum carried by the struck parton Electrons, muons, neutrinos SLAC, CERN, HERA, FNAL, JLAB E, E’ 5-500 GeV Q2 5-50 GeV2 Information about nucleon vertex is contained in F1 (x,Q2) and F2(x,Q2), the unpolarized structure functions w2 >4 GeV2 0 ≤ XB ≤ 1

16. DIS Nucleons Scale: several tens of GeV Nucleon in nuclei are bound by ~MeV Naive expectation : DIS off a bound nucleon = DIS off a free nucleon (Except some small Fermi momentum correction)

17. The European Muon Collaboration (EMC) effect DIS cross section per nucleon in nuclei ≠ DIS off a free nucleon

18. SLAC E139 Data from CERN SLAC JLab 1983- 2009

19. EMC is alocal density or nucleon momentum dependence effect,not a bulk property of nuclear medium JLab / Hall C J. Seely et al. PRL 103, 202301 (2009)

20. Theoretical interpretations: ~1000 of papers EMC recent review papers: Gessman, Saito,Thomas, Annu. Rev. Nucl. Part. Sci. 45:337(1995). P.R. Norton Rep Prog. 66 (2003). G. Miller: EMC = Every Model is Cool

21. A(e,e’)

22. : Comparing the magnitude of the EMC effect and the SRC scaling factors SRC scaling factor EMC slope SLAC data: Frankfurt, Strikman, Day, Sargsyan, Phys. Rev. C48 (1993) 2451. Gomez et al., Phys. Rev. D49, 4348 (1983). Q2=2, 5, 10, 15 GeV/c2 (averaged) Q2=2.3 GeV/c2

23. EMC: J. Seely et al. PRL 103, 202301 (2009) SRC: Hall B and Hall C data

24. PRL 106, 052301 (2011) EMC Slopes 0.35 ≤ XB ≤ 0.7 arXiv:1107.3583 nucl-ex SRC Scaling factors XB ≥ 1.4

25. Possible explanation for EMC / SRC correlation Where is the EMC effect ? 80% nucleons (20% kinetic energy) SRC np Mean field Largest attractive force 20% nucleons (80% kinetic energy) pp nn OR High local nuclear matter density, large momentum, large off shell. large virtuality ( ) See also talk by S. Strauch on nucleon modification as a function of the nucleon virtuality

26. Deuteron is not a free np pair EMC The slopes for 0.35 ≤ XB ≤ 0.7 0.079±0.06 bound to free n p pairs (as opposed to bound to deuteron) SRC A SRC=0 free nucleons

27. 0.079±0.06 0.975 0.5 Deuteron is not a free np pair EMC The slopes for 0.35 ≤ XB ≤ 0.7 SRC A SRC=0 free nucleons

28. In Medium Nucleon Structure Function, SRC, and the EMC Effect Proposal PR12-11-107 Spokepersons: O. Hen (TAU), L. B. Weinstein (ODU), S. A. Wood (JLab), S. Gilad (MIT) Collaboration: Experimental groups from : ANL, CNU, FIU, HU, JLab, KSU, MIT, NRCN, ODU, TAU, U. of Glasgow, U. of Ljubljana, UTFSM, UVa Theoretical support: Accardi, Ciofi Degli Atti, Cosyn, Frankfurt, Kaptari, Melnitchouk, Mezzetti, Miller, Ryckebusch, Sargsian, Strikman PAC 38 Aug. 2011

29. Measurement concept • Spectator Tagging: • Selects DIS off high momentum • (high virtuality) nucleons 2. cross sections ratio Minimize experimental and theoretical uncertainties RFSI is the FSI correction factor No ‘EMC effect ‘ is expected

31. Obstacles (FSI) Pd Pd p or n p or n Pd Pd θpq>107o 72o<θpq<107o What do we know about FSI: Decrease with Q2 Increase with W’ Not sensitive to x’ CLAS d(e,e’ps) vs. PWIA Decrease with recoil spectator angle How are we going to minimize(correct for) FSI: * Collect data at very large recoil angles (small FSI) and at ~900 (large FSI) * look at ratios of two different x’ *Use the low x’ large phase space to check / adjust the FSI calculations (Study the dependence of FSI on Q2, W' and θpq) *Get a large involvement of theoretical colleges at all stages of proposal, measurement, analysis

32. TOF Large Acceptance Detector (LAD) Use retired CLAS-6 TOF counters to detect recoiling nucleons (protons and neutrons) at backwards angles

33. Expected Results Binding/off shell Binding/off shell PLC suppression Rescaling model PLC suppression Rescaling model d(e,e’p) d(e,e’n) Melnitchouk, Sargsian, Strikman Z. Phys. A359 (97) 99.

34. 3 2 1 4 6 3 2 1 2 4 1 6 Summary I Standard model for short distance structure of nuclei CLAS / HALL B The probability for a nucleon to have momentum ≥ 300 MeV / c in medium nuclei is 20-25% More than ~90% of all nucleons with momentum ≥ 300 MeV / c belong to 2N-SRC. . PRL. 96, 082501 (2006) ~80% of kinetic energy of nucleon in nuclei is carried by nucleons in 2N-SRC. Probability for a nucleon with momentum 300-600 MeV / c to belong to np-SRC is ~18 times larger than to belong to pp-SRC. PRL 98,132501 (2007). Dominant NN force in the 2N-SRC is tensor force. EVA / BNL and Jlab / HALL A Repulsive force ? Three nucleon SRC are present in nuclei. PRL 162504(2006); Science 320, 1476 (2008).

35. EMC Summary II The EMC is a local density and / or momentum dependent and/or virtualery effect not a bulk property of the nuclear medium. SRC The magnitude of the EMC effect and SRC scaling factor are linearly related. We speculate that observed correlation arises because both EMC and SRC are dominated by high momentum (large virtuality) nucleons in nuclei. The observed relationship can be used to extract: thefree neutron structure function and the d/u ratio for proton DIS off the deuteron tagged by high momentum recoil spectator 0.079±0.06 JLab Proposal PR12-11-107 SRC=0 PAC 38 Aug. 2011

36. 12 GeV 0utlook For Q2=2 GeV/c2, x=1.2 HrS momentum acceptance ±4.5% 3 missing momentum setting SHMS momentum acceptance -10 - 22% Single setting BigBite 100 msr > 200 msr ~100 QE events `1000-5000 QE events

37. 12 GeV 0utlook A(e,e’) shows\ a second Plateau. What is the role played by non nucleonic degrees of freedom in SRC ? Are bound nucleons in SRC pairs different from free? m What is the role played by short range correlation of more than two nucleons ? Higher rate QE EMC SRC Higher energy DIS

39. n recoil signal / BG (large x) ~1:20

40. ) Ciofi,

41. The inclusive A(e,e’) measurements e/ e pi Adapted from Ciofi degli Atti q • At high nucleon momentum • distributions aresimilarin shape for • light and heavy nuclei:SCALING. • Can be explained by 2N-SRC dominance. • Within the 2N-SRC dominance picture one can get the probability of 2N-SRC in any nucleus, from the scaling factor. Problem: In A(e,e’) the momentum of the struck proton (pi) is unknown. Deuterium Solution: For fixed high Q2 and xB>1, xB determines a minimum pi Q2=2 GeV2 Prediction by Frankfurt, Sargsian, and Strikman:

42. e/ e pi q Deuterium Q2=2 GeV2

43. Estimate the amount of 2N-SRC in nuclei This includes all three isotopic compositions (pn, pp, or nn) for the 2N-SRC phase in 12C. a2N(A/d) pmin a2N(A/d) calculations measurement For Carbon:

44. Why several GeV and up protons are good probes of SRC ? They have small deBroglie wavelength:  = h/p = hc/pc = 2  0.197 GeV-fm/(6 GeV)  0.2 fm. Large momentum transfer is possible with wide angle scattering. The s-10 dependence of the p-p elastic scattering preferentially selects high momentum nuclear protons. For pp elastic scattering near 900 cm QE pp scattering near 900 has a very strong preference for reacting with forward going high momentum nuclear protons. 44

45. Why several GeV and up protons are good probes of SRC ? They have small deBroglie wavelength:  = h/p = hc/pc = 2  0.197 GeV-fm/(6 GeV)  0.2 fm. Large momentum transfer is possible with wide angle scattering. The s-10 dependence of the p-p elastic scattering preferentially selects high momentum nuclear protons. For pp elastic scattering near 900 cm QE pp scattering near 900 has a very strong preference for reacting with forward going high momentum nuclear protons. 45

46. The kinematics selected for the measurement p Pm = “300”,”400”,”500” MeV/c Ee’ = 3.724 GeV e’ Ee = 4.627 GeV 19.50 e 50.40 40.1, 35.8, 32.00 P = 300-600 MeV/c n or p p = 1.45,1.42,1.36 GeV/c Q2=2 (GeV/c)2 p qv=1.65 GeV/c 99 ± 50 X=1.245

47. Q>0 q=300-500 MeV/c pp/pn ratio as a function of pair CM momentum np pp q (fm-1) Q (fm-1) Wiringa, Schiavilla, Pieper, Carlson PRC 78 021001 (2008) Small Q  pp pair in s-wave  large tensor contribution  small pp/np ratio JLab / Hall B 300 < q < 500 MeV/c Hall A / BNL PRL 105, 222501(2010) Q pair CM momentum Q

48. Very weak Q2 dependence EMC JLab SLAC J. Gomez et al. J. Seely et al. SRC J. Arrington talk, Minami 2010.

49. k Fermi p e k k Fermi Fermi SRC in nuclei: implication for neutron stars • At the outer core of neutron stars, • ~95%neutrons, ~5%protons and ~5% electrons (β-stability). • Neglecting the np-SRC interactions, one can assume three separate Fermi gases (n, p, and e). At T=0 Pauli blocking prevent direct n decay n Strong SR np interaction

50. Frankfurt and Strikman: Int.J.Mod.Phys.A23:2991-3055,2008 SRC in nuclei: implication for neutron stars Strong SR np interaction