EMC effect and short-ranged correlations Gerald A. Miller - PowerPoint PPT Presentation

EMC effect and short-ranged correlations Gerald A. Miller University of Washington RMP with Or Hen, Eli Piasetzky, Larry Weinstein arXiv: 1611.09748 Will focus on 0.3 <x<0.7 Remarkable experimental progress Personal view of history, but mainly what I think is new I N T E R N A T I O N A L J O U R N A L O F H I G H -E N E R G Y P H Y S I C S CERNCOURIER Higinbotham, Miller, V O L U M E 5 3 N U M B E R 4 M A Y 2 0 1 3 Hen, Rith CERN Courier 53N4(’13)24 Deep in the nucleus: ����������������������������������������������������������������������������� �������������������������������������������������������������������� a puzzle revisited ���������������������������������������������������������������������������� ���������������������������������������������������������������������������� HEAVY IONS ASTROWATCH IT’S A HIGGS BOSON The key to fi nding Planck reveals an out if a collision almost perfect 1 is head on universe The new particle p31 p12 is identifi ed p21

The EMC EFFECT JLab Q 2 =3-6 GeV 2 1.2 σ C / σ D E03103 Norm. (1.6%) 1.1 SLAC Norm. (1.2%) 1.2 EMC E136 1 1.1 NMC E665 0.9 1 1.2 D σ Be / σ D Ca / F 2 E03103 Norm. (1.7%) 0.9 1.1 SLAC Norm. (1.2%) F 2 0.8 1 0.7 0.9 EIC 0.6 1.2 σ 4He / σ D E03103 Norm. (1.5%) 0.5 0.0001 0.001 0.01 0.1 1 1.1 SLAC Norm. (2.4%) x 1 White Paper 0.9 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 x For 0.3<x<0.7 ratio=R is approximately linear Nucleon structure is modified: valence quark momentum depleted. Why are ratios independent EFFECTS ARE SMALL ~15% 2 of Q 2 ?

The EMC EFFECT JLab Q 2 =3-6 GeV 2 1.2 σ C / σ D E03103 Norm. (1.6%) 1.1 SLAC Norm. (1.2%) 1.2 EMC E136 1 1.1 NMC E665 0.9 1 1.2 D σ Be / σ D Ca / F 2 E03103 Norm. (1.7%) 0.9 1.1 SLAC Norm. (1.2%) F 2 0.8 1 0.7 0.9 EIC 0.6 1.2 σ 4He / σ D E03103 Norm. (1.5%) 0.5 0.0001 0.001 0.01 0.1 1 1.1 SLAC Norm. (2.4%) x 1 White Paper 0.9 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 x For 0.3<x<0.7 ratio=R is approximately linear Nucleon structure is modified: valence quark momentum depleted. Why are ratios independent EFFECTS ARE SMALL ~15% 2 of Q 2 ?

Q 2 dependence of nuclear effects - 1 J.J. Aubert et al., Klaus Rith Nucl. Phys. B 481 (1996) 23 J. Gomez et al. J. Gomez et al., PRD 49 (1994) 4348 J. Seely et al., PRL 103 (2009) 202301 EMC EMC SLAC E139 SLAC E139 JLAB E03103 Q 2 dependence of EMC effect is small 3 Why? 25 K.R.

Ideas: ~1000 papers 3 ideas • Proper treatment of known effects: binding, Fermi motion, pionic- NO nuclear modification of internal nucleon/pion quark structure • Quark based- high momentum suppression implies larger confinement volume • bound nucleon is larger than free one- a a mean field effect • multi-nucleon clusters - beyond the mean b field 4

Ideas: ~1000 papers 3 ideas • Proper treatment of known effects: binding, Fermi motion, pionic- NO nuclear modification of internal nucleon/pion quark structure • Quark based- high momentum suppression implies larger confinement volume • bound nucleon is larger than free one- a a mean field effect • multi-nucleon clusters - beyond the mean b field EMC – “Everyone’s Model is Cool (1985)’’ 4

Ideas: ~1000 papers 3 ideas • Proper treatment of known effects: binding, Fermi motion, pionic- NO nuclear modification of internal nucleon/pion quark structure • Quark based- high momentum suppression implies larger confinement volume • bound nucleon is larger than free one- a a mean field effect • multi-nucleon clusters - beyond the mean b field EMC – “Everyone’s Model is Cool (1985)’’ 4

One thing I learned since ‘85 • Nucleon/pion model is not cool Deep Inelastic scattering from nuclei- nucleons only free structure function • Hugenholz van Hove theorem nuclear stability implies (in rest frame) P + =P - =M A • P + =A(M N - 8 MeV) • average nucleon k + k + =M N -8 MeV, Not much spread F 2A /A~F 2N no EMC effect Momentum sum rule- matrix element of energy Binding causes no momentum tensor EMC effect

More on sum rules • Baryon & momentum sum rules originate from matrix elements of conserved currents in the nucleon wave function-Collins book • The virtual photon -proton system is not the proton • Shadowing and final state interactions are not in the proton, sum rules do not apply to F A 2 • Sum rules apply to light front wave functions of the proton 6

Nucleons and pions 
 P A + = P N + + P π + =M A 
 P π + /M A =.04, explain EMC, sea enhanced 
 try Drell-Yan , Bickerstaff, Birse, Miller 84 proton(x 1 ) nucleus(x 2 ) x 1 x 2

Nucleons and pions 
 P A + = P N + + P π + =M A 
 P π + /M A =.04, explain EMC, sea enhanced 
 try Drell-Yan , Bickerstaff, Birse, Miller 84 proton(x 1 ) nucleus(x 2 ) x 1 x 2 σ DY (Fe) σ DY ( 2 H ) E772 PRL 69,1726 (92)

Nucleons and pions 
 P A + = P N + + P π + =M A 
 P π + /M A =.04, explain EMC, sea enhanced 
 try Drell-Yan , Bickerstaff, Birse, Miller 84 proton(x 1 ) nucleus(x 2 ) x 1 x 2 σ DY (Fe) σ DY ( 2 H ) Bertsch, Frankfurt, Strikman“crisis” E772 PRL 69,1726 (92)

Ideas: ~1000 papers 3 ideas • Proper treatment of known effects: binding, Fermi motion, pionic- NO nuclear modification of internal nucleon/pion quark structure • Quark based- high momentum suppression implies larger confinement volume • bound nucleon is larger than free one- a a I don’t see how you can get plateaus mean field effect at large x in a mean field model • multi-nucleon clusters - beyond the mean b field 8

Nucleon in nucleus q p + q γ ∗ On mass shell p p 2 6 = M 2 M A Off-mass shell Nucleus A-1 is form factor of a A-1 nucleus is low-lying state “large” proton A- 1 nucleus is 1 fast nucleon +A-2 nucleus b the struck nucleon is part of correlated pair SRC If Nucleus A-1 is highly excited, then p 2 − M 2 is big Such large virtuality occurs from two nearby correlated nucleons 9 Highly virtually nucleon is not a nucleon- different quark config.

Nucleon in nucleus q p + q γ ∗ On mass shell p p 2 6 = M 2 M A Off-mass shell Nucleus A-1 is form factor of a A-1 nucleus is low-lying state “large” proton A- 1 nucleus is 1 fast nucleon +A-2 nucleus b the struck nucleon is part of correlated pair SRC If Nucleus A-1 is highly excited, then p 2 − M 2 is big Such large virtuality occurs from two nearby correlated nucleons 9 Highly virtually nucleon is not a nucleon- different quark config.

Free nucleon Suppression of Point Like Configurations Frankfurt Strikman Schematic . . two-component + ✏ ✏ . . . . nucleon model Blob-like config:BLC Point-like config: PLC Bound nucleon PLC smaller, fewer quarks high x . . Medium interacts with BLC + ✏ ✏ . . . energy denominator increases M . PLC Suppressed | ✏ M | < | ✏ | U A-1 10

Quark structure of nucleon Frankfurt- Schematic Strikman two-component PLC BLC nucleon model: . . + ✏ . . Blob-like config:BLC . . gives high x Point-like config: PLC q(x) PLC does not Cioffi degli Atti ‘07 interact with  � E B V Free nucleon : H 0 = , V > 0 V E P nucleus A U = h v ( p , E ) i / 2 M 3 H = e e -34.59 V | N i = | B i + ✏ | P i , ✏ = E B − E P < 0 4 He -69.40 12 C -82.28  � E B � | U | V Lar In nucleus (M) : H = 16 O V E P -79.68 40 Ca -84.54 56 Fe -82.44 | N i M = | B i + ✏ M | P i , | ✏ M | < | ✏ | , PLC suppressed , ✏ M � ✏ > 0 amplitude e ff ect! 208 Pb -92.20 | N i M � | N i / ( ✏ M � ✏ ) / U = p 2 − m 2 nucleon correlations Shroedinger eq. large values from 2 M d f q M ( x ) = q ( x ) + ( ✏ M � ✏ ) f ( x ) q ( x ) , dx < 0 , x � 0 . 3 PLC suppression two nucleon correlations Simula R = q M q ; dR dx = ( ✏ M − ✏ ) d f dx < 0 Reproduces EMC e ff ect - like every model Why this model??? Large e ff ect if v = p 2 � m 2 is large, it is 11 EFT: Chen et al ‘16

Implications of model The two state model has a ground state | N i and an excited state | N ∗ i | N i M = | N i + ( ✏ M � ✏ ) | N ∗ i The nucleus contains excited states of the nucleon These configurations are the origin of high x EMC ratios Previously missing in models of the EMC effect- same model predicts some other effect 12

A(e,e’) at x>1 shows dominance of 2N SRC Q 2 x = x goes from 1 to A 2 M ν x=1 is exact kinematic limit for all Q 2 for the scattering off a free nucleon; x=2 (x=3) is exact kinematic limit for all Q 2 for the scattering off a A=2(A=3) system (up to <1% correction due to nuclear binding) M Strikman 1<x<2 picture Two nucleons cluster two nucleons of SRC are fast 4 13