Short-range NN interactions: Experimental Past and Future

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1 Short-range NN interactions: Experimental Past and Future 7th Workshop of the APS Topical Group on Hadronic Physics Nadia Fomin University of Tennessee February 1 st, 017

2 Independent Particle Shell Model : S 4 S(E m, p m )p m dp m (E m E ) For nuclei, S α should be equal to j+1 => number of protons in a given orbital However, it as found to be only ~/3 of the expected value The bulk of the missing strength it is thought to come from short range correlations

3 High momentum nucleons - Short Range Correlations N SRC 3N SRC Nucleon momentum distribution in 1 C

4 High momentum tails in A(e,e p) E89-004: Measure of 3 He(e,e p)d Measured far into high momentum tail: Cross section is ~5-10x expectation Difficulty High momentum pair can come from SRC (initial state) OR Final State Interactions (FSI) and Meson Exchange Contributions (MEC) slow nucleons fast nucleons p p p p

5 A(e,e p) H(e,e p) Mainz PRC (008) E =0.855 GeV θ = 45 o E =0.657 GeV Q =0.33 GeV x=0.88 Unfortunately: FSI, MECs overwhelm the high momentum nucleons

6 High momentum nucleons N SRC - Short Range Correlations 3N SRC Nucleon momentum distribution in 1 C Try inclusive scattering! Select kinematics such that the initial nucleon momentum > k f

7 N SRC 3N SRC High momentum nucleons - Short Range Correlations * 1 ) ( ), ( ' k M p M M Arg Arg E k S de dk de d d A A i ei QE ) ( ) ( ) ( 1 ), ( y n p kdk k n q y M N Z d d d y F q q Ok for A= Deuterium Fomin et al, PRL 108 (01)

8 High momentum nucleons - Short Range Correlations N SRC 3N SRC Nucleon momentum distribution in 1 C C. Ciofi degli Atti and S. Simula, Phys. Rev. C 53 (1996).

9 High momentum nucleons - Short Range Correlations N SRC 3N SRC Nucleon momentum distribution in 1 C High momentum from SRCs P>k fermi Mean field C. Ciofi degli Atti and S. Simula, Phys. Rev. C 53 (1996).

10 (x>1) x=1 (x<1) QE Jlab E0-019 JLab, Hall C, 1998 Deuteriu m

11 E0-019: N correlations in A/D ratios Fomin et al, PRL 108 (01) Jlab E0-019 <Q >=.7 GeV

12 Relative measurement Reduced FSI Test scaling in x and Q No direct information on isospin structure Only via target isospin structure No direct information on momentum distribution for A> Inclusive Scattering

13 Inclusive Scattering Relative measurement Reduced FSI Test scaling in x and Q No direct information on isospin structure Only via target isospin structure No direct information on momentum distribution for A> P>k fermi C. Ciofi degli Atti and S. Simula, Phys. Rev. C 53 (1996).

14 Relative measurement Reduced FSI Test scaling in x and Q No direct information on isospin structure Only via target isospin structure No direct information on momentum distribution for A> Inclusive Scattering

15 Test scaling in x and Q q M M 1 W 4M W 3 He 3 He 1 C 1 C

16 N knockout experiments establish NP dominance Knockout high-initialmomentum proton, look for correlated nucleon partner. For 300 < P miss < 600 MeV/c all nucleons are part of N-SRC pairs: 90% np, 5% pp (nn) R. Subedi et al., Science 30, 1476 (008) R. Shneor et al., PRL 99, (007)

17 N knockout experiments establish NP dominance 96 ± 3 % R. Subedi et al., Science 30, 1476 (008) 9.5 ± % R. Shneor et al., PRL 99, (007)

18 NP dominance 96 ± 3 % R. Subedi et al., Science 30, 1476 (008) 9.5 ± % R. Shneor et al., PRL 99, (007) also Ciofi and Alvioli PRL 100, (008) Sargsian, Abrahamyan, Strikman, Frankfurt PR C (005)

19 Data mining using CLAS NP dominance continues for heavy nuclei Assuming scattering off N-SRC pairs: (e,e p) is sensitive to np and pp pairs (e,e pp) is sensitive to pp pairs alone => (e,e pp)/(e,e p) ratio is sensitive to the np/pp ratio Slide courtesy O. Hen

20 Have not solved the nuclear dependence N correlations

21 Linear relationship with EMC effect Fit the slope of the ratios for 0.3<x<0.7: dr EMC dx J.Seely, A. Daniel, et al., PRL103, 0301 (009)

22 More nucleons in a correlation 1.4<x< => nucleon correlation.4<x<3 => 3 nucleon correlation A j j j Q x A a j A Q x 1 ), ( ) ( 1 ), ( ), ( ) ( Q x A a A... ), ( ) ( Q x A a A N SRC 3N SRC

23 3N correlations (x> inclusive scattering) K. Egiyan et al, PRL96, (006) <Q > (GeV ): CLAS: 1.6 E0-019:.7

24 Have we actually seen 3N SRC in ratios?

25 3N correlations

26 3N correlations are we there yet? α 3N_MIN =1.6 Where does N contribution become negligible?

27 Coming very soon: [Jlab E ] Quasielastic electron scattering with 3 H and 3 He Study isospin dependence of N and 3N correlations Test calculations of FSI for well-understood nuclei

28 Coming very soon: [Jlab E ] Quasielastic electron scattering with 3 H and 3 He Study isospin dependence of N and 3N correlations Test calculations of FSI for well-understood nuclei 1 3 p 3 =p 1 +p 1 3 p 3 =p 1 =p

29 Jlab E && E short-range nuclear structure - Isospin dependence - A-dependence Super-fast quarks

30 Jlab E && E short-range nuclear structure - Isospin dependence - A-dependence Super-fast quarks

31 Summary SRCs and EMC effect have been under the microscope for many decades 6GeV era at Jlab has yielded interesting data 1 GeV experiments continue the search Upcoming experiments in Halls A/C Study short range correlations in 3He/3H Map out nuclear dependencies of clustering Study how quark distributions are modified in nuclei over free nucleons New results in the next few years!

32 By popular demand σ A1 /σ A No hint of a second plateau at x>1.6 for Au/(A>=1)