1. “Backward” Particle Detection for 12 GeV in Hall C Eli Piasetzky Tel Aviv University, ISRAEL Hall C Meeting, January 18-19, 2008 Jefferson Lab, Newport News, VA USA

2. e e’ p,π,… Large solid angle multi particle (charge and neutral) detector HMSSHMS Coverage of a large fraction of the hemisphere (“backward” =4π-forward) consistent operation with the forward spectrometers. Ability to detect multi charge particles with good PID and moderate momentum resolution. Ability to detect neutrons with high efficiency. Ability to operate at 10-100% of the full luminosity of Hall C (10-100 times the planned luminosity for CLAS).

3. The physics driving a “4π-forward” detector Short Range Correlations (SRC) EMC Hadronization Study of GPDs Nuclear Matter in non - equilibrium condition

4. np-SRC dominance ~18 % 12 C Results summary The uncertainties allow a few percent of: more than 2N correlations Non - nucleonic degrees of freedom 2N –SRC dominance 18±5% 1±0.3% 12 C

5. 19±4% 0.6±0.2% 2N 3N PR 08-14 / PAC 33 1N >> 2N - SRC >> 3N – SRC. cure XB>2 or

6. ~800 MeV/c ~400 MeV/c star geometry Colinear geometry : From (e,e’p) + N to (e,e’p)+2N Exclusive measurement: From triple coincidence (2N SRC) to 4 fold coincidence (3N SRC) Needs large acceptance multi particle detector Need to detect two recoil nucleons 0.3-1 GeV/c p and n

7. Are the nucleons in the SRC pair different from free nucleons (e.g size,shape, mass, etc.) ? Are they nucleons ? For a 1 fm separation, the central density is about 4 times nuclear central density  1.f Nucleons 2N-SRC   4  o ~1 fm

8. Looking for non-nucleonic degrees of freedom The signature of a non-nucleonic SRC intermediate state is a large branching ratio to a non-nucleonic final state. Breaking the pair will yield more backward Δ, π, k  1.f Nucleons 2N-SRC   5  o ~1 fm

9. Looking for non-nucleonic degrees of freedom Expected Δ’s rates 5-10% of recoil N 4 fold coincidence 2 particles in the backward detector 3-5 fold coincidence 2-4 particles in the backward detector Detected by spectrometer

10. Title: Search for cumulative Delta 0 (1232) and Delta + + (1232) isobars in neutrino interactions with neon nuclei Authors:Ammosov, V. V.Ammosov, V. V.; Asratyan, A. É.; Burtovoǐ, V. S.; Gapienko, V. A.; Gapienko, G. S.; Gorichev, P. A.; Denisov, A. G.; Zaets, V. G.; Klyukhin, V. I.; Koreshev, V. I.; Kruchinin, S. P.; Kubantsev, M. A.; Makhlyueva, I. V.; Pitukhin, P. V.; Sirotenko, V. I.; Slobodyuk, E. A.; Usubov, Z. U.; Fedotov, A. V.; Shevchenko, V. G.; Shekelyan, V. I.Asratyan, A. É.Burtovoǐ, V. S. Gapienko, V. A.Gapienko, G. S. Gorichev, P. A.Denisov, A. G.Zaets, V. G. Klyukhin, V. I.Koreshev, V. I.Kruchinin, S. P. Kubantsev, M. A.Makhlyueva, I. V. Pitukhin, P. V.Sirotenko, V. I.Slobodyuk, E. A. Usubov, Z. U.Fedotov, A. V.Shevchenko, V. G. Shekelyan, V. I. Publicati on: Journal of Experimental and Theoretical Physics Letters, Vol. 40, p.1041 Publicati on Date: 09/1984

11. Δ Kinematics p Δ =640 MeV/c With SHMS(e) and HMS(p) acceptances and Γ=110 MeV Needs large acceptance multi particle detector

12. Extrapolation factor ~10 Measured ratio Extrapolated ratio The Limited acceptance allows determination of only two components of the pair cm momentum. Even the triple coincidence SRC experiment could be done better with a larger acceptance detector.

13. A large acceptance detector allows tagging of the DIS event EMC High nuclear density tagging : A recoil high momentum nucleon to the backward hemisphere is a signature of 2N-SRC i.e large local nuclear density. Due to the dominance of np-SRC pairs: a recoil neutron tags a proton structure function a recoil proton tags a neutron structure function Flavor tagging : Identifying a π + or π - with a large z can point to the flavor of the struck quark ( u or d). Recoil and forward tagging allows the study of u, d in p, n

14. Hadronization Measure the multiplicity and the type of emitted particles in a large acceptance “backward direction ” in coincidence with the forward (large z) leading π +, π -, k +, k - particle. Difference in hadronization of different quarks Difference between hardonization in a free space and nuclear medium

15. GPDs Hall C With a large acceptance detector: low mass πN system- a test of chiral symmetry With Deuteron one can measure imultaneously both proton and neutron by detecting the recoil neutron or proton respectively ? Hall B

16. Nuclear Matter in non - equilibrium condition Using hard processes to remove a single or a few nucleons from the nucleus creates a non-stable state. How does such a non-stable state decay to a stable system?

17. Large solid angle- 4π – non-symmetric opening in the forward hemisphere Large (full) luminosity Can operate in coincidence with small solid angle, high resolution spectrometer / spectrometers Multi particle detection Particle ID p e e’ Δ p A (4π – forward) DETECTOR Cover up to ~180 0 (the planed 12GeV CLAS cover up to 135 0 only)

18. G0 BONUS TPC

19. π p d beam ~200 counters PID

20. π p d beam ~200 counters 20 cm 5 cm Also E vs. ΔE PID TOF ΔEΔE n-detection efficiency ~20% +15%(?) LAC

21. Short Range Correlations (SRC) EMC Hadronization Study of GPDs Nuclear Matter in non - equilibrium condition 2-3 physics proposals to the 12 GeV PAC Conceptual detector design 2008

22. Acknowledgment Stepan Stepanyan Sebastian Kuhn Steve Wood Rolf Ent Discussions and ideas exchange with: Larry Weinstein

23. Large Angle Calorimeter (LAC) 2 mm lead foil 1.5 cm plastic Scintillator 33 layers neutron momentum [GeV/c]

24. Improve n-detection For the new 12 GeV clas: The current magnet, Drift chambers, and scintillator counters are not to be used. The CLAS as a 4π-forward detector Need new power supplies, and electronics Require a careful, non trivial dismount of the current detector at Hall B and non trivial setup at hall c.

25. The CLAS as a 4π-forward detector TOF CER CAL DC1 DC2 DC3

26. CLAS 3-D View

27. G0

29. BONUS TPC

30. How to relate what we learned about SRC in nuclei to the dynamics of neutron star formation and structure ? SRC in nuclei NN interaction: what is the role played by the repulsive core ? Are the nucleons in the SRC pair different from free nucleons (e.g size,shape, mass, etc.) ? Are they nucleons ? What is the role played by short range correlation of more than two nucleons ? SRC in nuclei Roadmap  1.f Nucleons 2N-SRC 1.7f  o = 0.16 GeV/fm 3   5  o ~1 fm 1.7 fm

31. 12 C: 18±4.5 % 0.95 ± 0.2 % 2N-SRC np-SRC pp-SRC nn-SRC 20±4.5 % 80±4.5% The uncertainties allow a few percent of: more than 2N correlations Non nucleonic degrees of freedom A single “particle” in an average potential

32. Identifying Future Experiments Looking for SRC with more than 2 nucleons:

33. Identifying Future Experiments Looking for SRC with more than 2 nucleons: The problems: The cross sections are small. 1N >> 2N - SRC >> 3N – SRC. star geometry : What is the signature for 3N correlation ? Questions What is the difference from two 2N correlations ? What is the expected isospin structure of the 3N ?

34. Identifying Future Experiments Looking for SRC with more than 2 nucleons: The problems: The cross sections are small. 1N >> 2N - SRC >> 3N – SRC. The cure for 1N background is : large p miss and/or large X B The cure for 2N-SRC: X B >2 or suppression of the 2N-SRC at p rel =300-600 MeV/c for nn or pp pairs.

35. Identifying Future Experiments Looking for SRC with more than 2 nucleons: Colinear geometry : Initial configurations ~800 MeV/c The signal of today is tomorrow’s background The 2N-SRC interaction is suppressed, opening a window of opportunity to identify 3N correlation. ~400 MeV/c A very strong isospin dependence is expected for the 2N part. For the 3N?

36. Identifying Future Experiments Looking for SRC with more than 2 nucleons: Colinear geometry ~800 MeV/c FSI are strong function of θ SRC are not

37. Identifying Future Experiments Looking for non-nucleonic degrees of freedom The signature of a non-nucleonic SRC intermediate state is a large branching ratio to a non nucleonic final state. Breaking the pair will yield more backward Δ, π, k  1.f Nucleons 2N-SRC   5  o ~1 fm

38. Looking for non-nucleonic degrees of freedom In coincidence with (e, e’p), as a function of the missing momentum we want to detect; p, n, π-, π+ k - triple coincidence

39. Identifying Future Experiments Looking for non-nucleonic degrees of freedom  pΔ 0  p π - p “np”  pn “pp”  pp  pΔ +  p π+ n 4 fold coincidence Expected rates 5-10% of recoil N

40. Δ Kinematics

41. p e e’ n or p p Pm = “300”,”400”,”500” MeV/c 99 ± 5 0 P = 300-600 MeV/c Ee = 4.627 GeV Ee’ = 3.724 GeV Q 2 =2 (GeV/c) 2 q v =1.65 GeV/c 50.4 0 19.5 0 40.1, 35.8, 32.0 0 p = 1.45,1.42,1.36 GeV/c The selected kinematics for E01-015 X=1.245 Increasing, energy, ω,N  Δ ?

42. p e e’ Δ p Ee = 11 GeV Ee’ = 9.8 GeV Q 2 =2.5 (GeV/c) 2 q v =1.65 GeV/c 48.5 0 8.8 0 34 0 p = 1.32 GeV/c The selected kinematics X=1.12 Increasing, energy and ω, N  Δ P miss =770 MeV/c P Δ =770 MeV/c Cannot produce backward going Δ. Cannot produce larger momentum difference between the recoil Δ and the struck nucleon. p e e’ Δ p p = 1.32 GeV/c P miss =1.32 GeV/c P Δ =770 MeV/c

43. Ee= 11.00000 Eout= 9.960000 theta_e = 8.200000 Q2= 2.240232 x= 1.147892 input angle of (qe) and (qp) planes 0.0000000E+00 theta of q: -51.20859 The format of the following output is: type of the particle, momentum, angle vs q, angle vs e, azimuthal angle in lab knock-out nucleon 1.200000 5.490372 45.71821 180.0000 missing 0.6385024 169.6408 118.4322 0.0000000E+00 recoil 0.6385024 10.35917 61.56776 180.0000 tet between recoil and scattred proton -15.84955 pmiss in the q direction 0.6280947 Ee= 11.00000 Eout= 9.790000 theta_e = 8.800000 Q2= 2.535372 x= 1.116600 input angle of (qe) and (qp) planes 0.0000000E+00 theta of q: -48.49650 The format of the following output is: type of the particle, momentum, angle vs q, angle vs e, azimuthal angle in lab knock-out nucleon 1.328000 13.52419 34.97231 180.0000 missing 0.7737520 156.3361 107.8397 0.0000000E+00 recoil 0.7737520 23.66388 72.16035 180.0000 tet between recoil and scattred proton -37.18803 pmiss in the q direction 0.7086919

44. p e e’ Δ p Pm = “640 MeV/c 100 0 Ee = 11 GeV Ee’ = 9 GeV Q 2 =2 (GeV/c) 2 q v =2.5 GeV/c 31.5 0 8.2 0 16.6 0 p = 2.3 GeV/c The selected kinematics for the measurement X=0.5 P Δ = “640 MeV/c Ee= 11.00000 Eout= 9.000000 theta_e = 8.200000 Q2= 2.024307 x= 0.5393709 input angle of (qe) and (qp) planes 0.0000000E+00 theta of q: -31.53330 The format of the following output is: type of the particle, momentum, angle vs q, angle vs e, azimuthal angle in lab knock-out nucleon 2.300000 14.94191 16.59142 179.9802 missing 0.6368749 111.3839 79.85064 0.0000000E+00 recoil 0.6368749 68.61605 100.1494 180.0000 tet between recoil and scattred proton -83.55794 pmiss in the q direction 0.2322146

45. p Δ =640 MeV/c With SHMS(e) and HMS(p) acceptances and Γ=110 MeV With SHMS(e) and HMS(p) acceptances Needs large acceptance multi particle detector

46. Large solid angle- 4π – non symmetric gape at the forward hemisphere Large (full) luminosity Can operate in coincidence with small solid angle high resolution spectrometer / spectrometers Multi particle detection Particle ID p e e’ Δ p The L arge A cceptance M INUS F ORWARD detector

48. CLAS12 Solenoid Toroid Calorimeter CF 4 Cerenkov Toroidal field  < 45 o Solenoidal field 45 <  < 135 o DC TOF CO 2 Cer

49. SRC in nuclei Are the nucleons in the SRC pair different from free nucleons (e.g size,shape, mass, etc.) ? Are they nucleons ? What is the role played by short range correlation of more than two nucleons ? SRC in nuclei Roadmap  1.f Nucleons 2N-SRC 1.7f  o = 0.16 GeV/fm 3   5  o ~1 fm 1.7 fm

50. 12 C: 18±4.5 % 0.95 ± 0.2 % 2N-SRC np-SRC pp-SRC nn-SRC 20±4.5 % 80±4.5% The uncertainties allow a few percent of: more than 2N correlations Non nucleonic degrees of freedom A single “particle” in an average potential

52. LAC TOF scintillators