High Momentum Nucleons: where have we been and where are we going

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1 High Momentum Nucleons: where have we been and where are we going Nadia Fomin High Energy Nuclear Physics with Spectator Tagging March 10 th, 015

2 High momentum nucleons where do they come from? Independent Particle Shell Model : S 4 S(E m, p m )p m dp m (E m E ) Proton E m,p m distribution modeled as sum of independent shell contributions (arbitrary normalization)

3 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

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

6 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

7 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

8 Past A(e,e p) experiments in Hall A

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10 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

11 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)

12 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).

13 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).

14 Short Range Correlations To experimentally probe SRCs, must be in the high-momentum region (x>1) To measure the relative probability of finding a correlation, ratios of heavy to light nuclei are taken In the high momentum region, FSIs are thought to be confined to the SRCs and therefore, cancel in the cross section ratios L. L. Frankfurt and M. I. Strikman, Phys. Rept. 76, 15(1981). J. Arrington, D. Higinbotham, G. Rosner, and M. Sargsian (011), arxiv: L. L. Frankfurt, M. I. Strikman, D. B. Day, and M. Sargsian, Phys. Rev. C 48, 451 (1993). L. L. Frankfurt and M. I. Strikman, Phys. Rept. 160, 35 (1988). C. C. degli Atti and S. Simula, Phys. Lett. B 35, 76 (1994). C. C. degli Atti and S. Simula, Phys. Rev. C 53, 1689 (1996). ( ) A DA a A 1.4<x< => nucleon correlation.4<x<3 => 3 nucleon correlation A 1 ( x, Q ) A a j ( A) j ( x, Q j j 1 A a( A) ( x, Q ) A 3 a3( A) 3( x, Q )... )

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

16 Before my time A j j j Q x A a j A Q x 1 ), ( ) ( 1 ), ( ), ( ) ( Q x A a A... ), ( ) ( Q x A a A 1.4<x< => nucleon correlation.4<x<3 => 3 nucleon correlation

17 Short Range Correlations To experimentally probe SRCs, must be in the high-momentum region (x>1) To measure the relative probability of finding a correlation, ratios of heavy to light nuclei are taken In the high momentum region, FSIs are thought to be confined to the SRCs and therefore, cancel in the cross section ratios 1.4<x< => nucleon correlation.4<x<3 => 3 nucleon correlation L. L. Frankfurt and M. I. Strikman, Phys. Rept. 76, 15(1981). J. Arrington, D. Higinbotham, G. Rosner, and M. Sargsian (011), arxiv: L. L. Frankfurt, M. I. Strikman, D. B. Day, and M. Sargsian, Phys. Rev. C 48, 451 (1993). L. L. Frankfurt and M. I. Strikman, Phys. Rept. 160, 35 (1988). C. C. degli Atti and S. Simula, Phys. Lett. B 35, 76 (1994). C. C. degli Atti and S. Simula, Phys. Rev. C 53, 1689 (1996). ( ) A DA a A

18 Previous measurements 1.4<x< => nucleon correlation.4<x<3 => 3 nucleon correlation Egiyan et al, Phys.Rev.C68, 003 No observation of scaling for Q <1.4 GeV

19 Kinematic cutoff is A-dependent For heavy nuclei, the minimum momentum changes heavier recoil system requires less kinetic energy to balance the momentum of the struck nucleon Larger fermi momenta for A> MF contribution persists for longer

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

21 Q dependence features q M M 1 W 4M W 3 He 3 He 1 C 1 C

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

23 a -1 Look at nuclear dependence of NN SRCs N. Fomin et al, PRL 108 (01) SRC

24 (a =σ A /σ D )!= Relative #of SRCs Convolution n CONV (k) D is the convolution of n D (k) with the CM motion of correlated pairs in iron Deuteron Following prescription from C. Ciofi degli Atti and S. Simula, Phys. Rev. C 53 (1996) a =σ A /σ D relative measure of high momentum nucleons R n relative measure of correlated pairs

25 Both driven by a similar underlying cause? Separation Energy For SRCs, a linear relationship with <ε> is less suggestive S.A. Kulagin and R. Petti, Nucl. Phys. A 176, 16 (006)

26 Both driven by a similar underlying cause? A -1/3 Apply exact NM calculations to finite nuclei via LDA (A. Antonov and I. Petkov, Nuovo Cimento A 94, 68 (1986) (I. Sick and D. Day, Phys. Lett B 74, 16 (199)) SRCs less compelling For A>1, the nuclear density distribution has a common shape; constant in the nuclear interior (bulk) Scale with A Nuclear surface contributions grow as A /3 (R ) σ per nucleon would be constant with small deviations that go with A -1/3

27 10+ years ago.in Hall C H 3 He 4 He 9 Be 1 C 7 Al* 63 Cu 197 Au

28 Physics Tend to Fill the Open Space p p Scintillato r Array p Wire Chamber s de and E planes n 3x3x1 m 3 slide courtesy of O. Hen 8

29 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)

30 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)

31 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)

32 NP dominance: momentum dependent R. Subedi et al., Science 30, 1476 (008) R. Shneor et al., PRL 99, (007) I. Korover et al, PRL 113 (014) 0501 also Ciofi and Alvioli PRL 100, (008) Sargsian, Abrahamyan, Strikman, Frankfurt PR C (005)

33 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

34 Why not more nucleons in a correlation?

35 Further evidence of multi-nucleon correlations K. Egiyan et al, PRL96, (006) <Q > (GeV ): CLAS: 1.6 E0-019:.7 Excellent agreement for x Very different approaches to 3N plateau, later onset of scaling for E0-019 Very similar behavior for heavier targets

36 E08-014: Study 3N correlations Map Q dependence of 3N plateau Verify Isospin Dependence with 40 Ca and 48 Ca HRS-L Analysis in final stages target HRS-R

37 E08-014: Study 3N correlations Plot courtesy of Z. Ye

38 Coming soon at 1 (well.11) GeV

39 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

40 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

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

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

43 In-Medium Nucleon Structure Functions [E11-107: O. Hen, L.B. Weinstein, S. Gilad, S.A. Wood] DIS scattering from nucleon in deuterium Tag high-momentum struck nucleons by detecting backward spectator nucleon in Large-Angle Detector R ~ F tagged /F untagged Projected uncertainties a S = (E S - p S Z ) / m S

44 In-Medium Nucleon Form Factors [E11-00: E. Brash, G. M. Huber, R. Ransom, S. Strauch]? Compare proton knockout from dense and thin nuclei: 4 He(e,e p) 3 H and H(e,e p)n Modern, rigorous H(e,e p)n calculations show reaction-dynamics effects and FSI will change the ratio at most 8% QMC model predicts 30% deviation from free nucleon at large virtuality S. Jeschonnek and J.W. Van Orden, Phys. Rev. C 81, (010) and Phys. Rev. C 78, (008); M.M. Sargsian, Phys. Rev. C8, (010)

45 Summary SRCs have been under the microscope for many decades 6GeV era at Jlab has yielded interesting data 1 GeV experiments continue the search New results in the next few years!

46 Overlapping nucleons enhancement of F structure function two-nucleon only two-nucleon only 5% 6 quark bag 5% 6 quark bag q D (x) Small effect, possible contribution to EMC effect? Noticeable effect at x>1

47 Superfast quarks Current data at highest Q (JLab E0-019) already sensitive to partonic behavior at x>1 N. Fomin et al, PRL 105, 150 (010)

48 Both driven by a similar underlying cause? Separation Energy J. Arrington, A. Daniel, D. Day, NF, D. Gaskell, P. Solvignon PRC86 (01) Separation energies were calculated from spectral functions, including MF and correlations S.A. Kulagin and R. Petti, Nucl. Phys. A 176, 16 (006)