eli piasetzky

Eli PiasetzkyTel Aviv University, ISRAELShort Range Correlations and the EMC Effect Work done in collaboration with:

L. B. Weinstein (ODU) D. Higinbotham, J. Gomez (JLab) O. Hen, R. Shneor (TAU)

Deep Inelastic Scattering (DIS) EE`(,q)nucleonFinal state Hadrons W2Incident leptonE, E 5-500 GeVQ2 5-50 GeV2w2 >4 GeV20 XB 1

xB gives the fraction of nucleon momentum carried by the struck partonInformation about nucleon vertex is contained in F1 (x,Q2) and F2(x,Q2), the unpolarized structure functionsscattered leptonElectrons, muons, neutrinos

DIS is a hard process that has the resolving power required to probe the partonic structure of hadronsScale: several tens of GeVNucleon in nuclei are bound by ~MeVNaive expectation :DIS off a bound nucleon = DIS off a free nucleon (Except some small Fermi momentum correction)

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

SLAC E139Data from CERN SLAC JLab 1983- 2009Theoretical interpretations: hundreds of papersG. Miller: EMC = Every Model is Cool

J. Seely et al. PRL 103, 202301 (2009)JLab / Hall C EMC is a local density effect, not a bulk property of nuclear medium

E, E 3-5 GeVQ2 2 GeV20 XB ANucleons2N-SRCxB counts the number of hadrons involved EE`(,q)Incident electronscattered electronnucleusInclusive electron scattering A(e,e) A hard process that has the resolving power required to probe the partonic structure of nuclei

Inclusive A(e,e) measurements

At high nucleon momentum, distributions are similar in 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. DeuteriumQ2=2 GeV2For fixed high Q2 and xB>1, xB determines a minimum pi Prediction by Frankfurt, Sargsian, and Strikman:

Observed scaling means that electrons probe high-momentum nucleons in 2(3) -nucleon phase. The scaling factors determine the per-nucleon probability of the 2(3) N-SRC phase in nuclei with A>3, relative to 3He. K. Sh. Egiyan et al. PRL. 96, 082501 (2006)The probabilities for 3N SRC are smaller by one order of magnitude relative to the 2N SRC.JLab. CLAS A(e,e') ResultK. Sh. Egiyan et al. PRC 68, 014313 (2003)For 12C 2N-SRC (np, pp, nn) = 20 4.5%.More r(A,d) data:SLAC D. Day et al. PRL 59,427(1987) JLab. Hall C E02-019

New Preliminary Results from JLab Hall C (E02-019)a2N(A/d) Q2=2.5GeV2

:EMC slopeSRC scaling factorComparing the magnitude of the EMC effect and the SRC scaling factors Frankfurt, Strikman, Day, Sargsyan, Phys. Rev. C48 (1993) 2451.Q2=2.3 GeV/c2Gomez et al., Phys. Rev. D49, 4348 (1983).Q2=2, 5, 10, 15 GeV/c2 (averaged)SLAC data:

EMCSlopes 0.35 XB 0.7SRC Scaling factors XB 1.4

0.0790.06Deuteron is not a free np pairSRC=0 free nucleonsAEMCSRC bound to free n p pairs (as opposed to bound to deuteron)The slopes for 0.35 XB 0.7

For 0.35 XB 0.7The free neutron structure functionSLAC Data, J. Arrington et al. JPG 36(2009)205005. World parameterization of Fd, Fp Corrected for the EMC effect as calculated in a PLC modelExtracted from this work Fermi smearing using relativistic deuteron momentum densityWith medium correction

Where is the EMC effect ? High local nuclear matter density, large momentum, large off shell. large virtuality ( )Largest attractive forceMean field SRCNuclei are optimized to yield the strongest EMC effect possible OR 80% nucleons(20% kinetic energy)20% nucleons(80% kinetic energy)npppnn

How large is EMC effect in dense nuclear systems?What are the consequences of a large EMC in these systems?Central HI collisionsn stars

Summary 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 phenomenological relationship is used to extract: DIS cross section for a free neutron.ratio of deuteron to free n p pair cross sections.F2n(x,Q2), the free neutron structure function.( For 0.35 < XB < 0.7 )The EMC is a local density effect not a bulk property of the nuclear medium.EMCSRC0.0790.06SRC=0

I thanks the organizers for the invitationarXiv:1009.5666[hep-ph]

A triple coincidence measurement(E07-006)K 1 > KF , K 2 > KF K 1K 2K 1 -K 2Redefine the problem in momentum spaceKF ~250 MeV/c Hard exclusive measurements

Fe(e,epp)Pb(e,epp)JLab / CLAS Data Mining, EG2 data set, Or Chen et al. Q2=2GeV/c2Ein =5.014 GeV X>1.2

BNL / EVA12C(e,epn) / 12C(e,ep)[12C(e,epp) / 12C(e,ep)] / 2[12C(e,epn) / 12C(e,epp)] / 2R. Subedi et al., Science 320, 1476 (2008).

At 300-500 MeV/c, there is excess strength in np momentum distribution due to strong correlations induced by the tensor NN potential.3He3HeV18Bonnnpnppnpppppp3HeSchiavilla, Wiringa, Pieper, Carson, PRL 98,132501 (2007). Sargsian, Abrahamyan, Strikman, Frankfurt PR C71 044615 (2005).Ciofi and AlvioliPRL 100, 162503 (2008).

80 4.5 % - single particle moving in an average potential.20 4.5 % - 2N SRC .18 4.5 % - SRC np pairs .0.950.2% - SRC pp pairs.0.950.2 % - SRC nn pairs.Small ~1% - SRC of more than 2 nucleons.60-70 % - independent particle in a shell model potential.10-20 % - shell model long range correlationsDeduced short range 12C structure is:(e,e)(e,e)

(e,ep)(p,2pn)(e,epN)? ~1% -non nucleonic degrees of freedom74-92 %4.751%4.751%n-p pairsp-p pairsn-n pairs2N-SRC

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What did we learn recently about SRC ?The probability for a nucleon to have momentum 300 MeV / c in medium nuclei is ~25%More than ~90% of all nucleons with momentum 300 MeV / c belong to 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.Three nucleon SRC are present in nuclei. . PRL. 96, 082501 (2006)PRL 162504(2006); Science 320, 1476 (2008).CLAS / HALL BEVA / BNL and Jlab / HALL ADominant NN force in the 2N-SRC is tensor force. PRL 98,132501 (2007).Standard model for short distance structure of nuclei~80% of kinetic energy of nucleon in nuclei is carried by nucleons in 2N-SRC.

n-p pairsp-p pairsn-n pairsC12Single nucleons60-70%2N-SRC74-92 %10-20%205%4.751%2N-SRCA(e,ep)A(e,e)pnEgiyan et al. PRC 68, 014313.Egiyan et al. PRL. 96, 082501 (2006)Tang et al. PRL 042301 (2003)Piasetzky, Sargsian, Frankfurt, Strikman, Watson PRL 162504(2006).12C(p,2p n)A(e,epN)4.751%Long range (shell model) correlationsSummary of ResultsR. Subedi et al., Science 320, 1476 (2008).

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SRC EMCSlope 0.3 XB 0.7J. Gomez et al. Phys. Rev.D49, 4348 (1983)EMC dataN. Fomin Ph. D thesis, UVA (2007) arXiv:0812.2144SRC dataJ. Seely et al. Phys. Rev. Lett. 103,202301 (2009)K. Egiyan et al. Phys. Rev Lett. 96,082501 (2006).Scaling factors XB 1.2

SRC EMCSlope 0.3 XB 0.7

Q2 dependence of the EMC effectJ. Seely et al. PRL 103, 202301 (2009)EMC data:Gomez et al. : average over 2, 5, 10, 15 GeV/c2Seely et al. : 5.3 GeV/c2

Q2 for a2:Nadia: 2.71Egiyan: 1.4 - 2.6Day: 1 - 3

J. Seely et al. PRL 103, 202301 (2009)The average density is calculated from the ab initio Greens Function Monte Carlo calculation of the spatial distributions of Pieper and Wiringa, Annu. Rev. Nucl. Part. Sci. 51, 53 (2001).Hall C preliminary data, N. Fomin Ph. D thesis, UVA (2007) arXiv:0812.2144

probability for a nucleon to have momentum 300 MeV / c in medium nuclei is ~25%more than ~90% of all nucleons with momentum 300 MeV / c belong to 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.Three nucleon SRC are present in nuclei. . PRL. 96, 082501 (2006)PRL 162504(2006); Science 320, 1476 (2008).CLAS / HALL BEVA / BNL and Jlab / HALL Adominant NN force in the 2N-SRC is tensor force. PRL 98,132501 (2007).~80% of the kinetic energy of nucleon in nuclei is carried by nucleons in 2N-SRC.We know more about SRC from Hard exclusive measurements