Nuclear PDFs & leptonnucleon scattering From Quarks to Hadrons - PowerPoint PPT Presentation

Nuclear PDFs & lepton—nucleon scattering From Quarks to Hadrons Fred Olness SMU Thanks for substantial input from my friends & colleagues JLab 16 July 2020

“QCD is our most perfect physical theory” Frank Wilczek 2 arXiv:hep-ph/9907340 QCD is our most perfect physical theory What QCD Tells Us About Nature – and Why We Should Listen. Frank Wilczek In many respects, our most complex 111111 000000 000000 111111 000000 111111 000000 111111 000000 111111 00000 11111 000000 111111 111111 000000 00000 11111 111111 000000 00000 11111 000000 111111 00000 11111 000000 111111 11111 00000 11111 00000 000000 111111 00000 11111 11111 00000 111111 000000 000000 111111 11111 00000 111111 000000 11111 00000 0000 1111 111111 000000 00000 11111 000000 111111 0000 1111 111111 000000 111111 000000 0000 1111 111111 000000 00000 11111 111111 000000 1111 0000 000000 111111 00000 11111 0000 1111 00000 11111 asymptotic freedom 0000 1111 00000 11111 0000 1111 111 000 00000 11111 1111 0000 000 111 00000 11111 000 111 1111 0000 111 000 11111 00000 000 111 1111 0000 111 000 11111 00000 111 000 1111 0000 000 111 111 000 111 000 111 000 000 111 000 111 000 111 00 11 000 111 000 111 11 00 000 111 00 11 111 000 000 111 00 11 111 000 111 000 11 00 strong color confinement 111 000 00 11 111 000 000 111 11 00 000 111 00 11 000 111 000 111 00 11 000 111 000 111 00 11 00 11 111 000 000 111 00 11 11 00 111 000 00 11 111 000 00 11 11 00 00 11 11 00 00 11 00 11 11 00 00 11 11 00 11 00 … associated manifestations 11 00 11 00 11 00 111 000 00 11 111111 000000 000000 111111 111 000 11 00 000000 111111 111111 000000 000 111 00 11 111111 000000 000000 111111 111 000 00 11 000000 111111 111111 000000 000 111 111111 000000 11 00 111 000 000000 111111 000 111 000 111 11 00 11 00 000 111 000 111 000 111 00 11 111 000 111 000 00 11 000 111 000 111 11 00 000 111 111 000 00 11 111 000 000 111 1111 0000 11 00 1111 0000 000 111 1111 0000 0000 1111 000 111 1111 0000 0000 1111 000 111 1111 0000 1111 0000 1111 0000 0000 1111 0000 1111 0000 1111 1111 0000 0000 1111 1111 0000 1111 0000 000 111 11 00 0000 1111 111 000 00 11 1111 0000 000 111 00 11 111 000 11 00 111 000 11 00 000 111 00 11 000 111 00 11 000 111 00 11 111 000 11 00 111 000 11 00 000 111 11 00 111 000 11 00 000 111 11 00 Lessons: The Nature of Nature 000 111 11 00 000 111 11 00 000 111 11 00 000 111 00 11 00 11 111 000 000 111 00 11 11 00 00 11 11 00 111 000 00 11 111 000 00 11 000 111 000 111 111 000 111 000 000 111 000 111 0000 1111 000 111 0000 1111 000 111 0000 1111 111 000 0000 1111 “… alien, simple, beautiful, weird, & comprehensible" 000 111 0000 1111 11111 00000 00000 11111 00000 11111 00000 11111 000000 111111 11111 00000 11111 00000 11111 00000 111111 000000 11111 00000 11111 00000 11111 00000 111111 000000 11111 00000 11111 00000 11111 00000

PDFs & the Parton Model … a few simpifications 3 DGLAP violation??? saturation resummation hi-x QCD QED low-Q 2 higher twist non-linear QCD f a ( x ) … working in the limit of a spherical horse ... The QCD Parton Model Parameterized in terms of a single variable x, the momentum fraction … use DGLAP to determine Q dependence

4 Nuclear PDFs: Complementary efforts in general agreement nCTEQ15 looks EPS16 pretty good DSSZ HKN07 Nuclear PDFs are more complex more DOF than Proton case more “issues” to consider Nuclear vs Proton Uncertainties more work to do ...

5 The Challenges

6 nPDFs: Extend Kinematic Reach in {x,Q 2 } High-x: Nuclear PDFs: x>1 allowed; Nuc /F 2 Iso in Fermi region impacts F 2 Target Mass Corrections pick up M 2 /Q 2 higher twist Deuteron Corrections Q cut impacts F 2 Nuc /F 2 Deuteron ratio W cut Warm-up: JLab Data @ Hi-X Low-Q 2 Low-Q 2 : extend nCTEQ framework for this region & prepare for EIC Non-Perturbative inteface Low-x: Efrain Segarra w/ nCTEQ collective efgects Shadowing Target Mass Corrections Recombination pick up M 2 /Q 2 higher twist Resummation F L at low Q 2 access to g(x) Run at multiple energies

7 nCTEQ Wish List Fred Olness w/ help from: Tim Hobbs, Aleksander Kusina, Pavel Nadolsky, Tomas Jezo, Thia Keppel, Michael Klasen, Karol Kovarik, Jorge Morfin, Ingo Schienbein, Efrain Segarra, Steve Sekula Low-Q: Higher-Twist, Non-Pert, Resummation Hi-x: TMC, Nuclear x>1, … EIC Handbook Strange PDF: Disentangle: 1) proton PDF 2) nuclear corrections 3) fmavor components Gluon (& Charm+Bottom): Improve R G via F L : window on NLO and mass efgects Nuclear A: Map out A dependence … and maybe beyond

8 Case Study: The Strange PDF true uncertainty

Strange PDF: º N di-muon Production 9 Need to “dig out” s(x) underneath d(x) Extract s(x) Extract s(x) m + m - m - m + n m n m c c s s N N X extract s & s-bar X separately

Where do nuclear corrections come from ???? 10 We need to deal with the Nuclei The ratio of iron (Fe) to Deuterium (D) Independent of Q, A, F 123 , ... Discovered by the French in 1799 at Rosetta, a harbor on the Mediterranean coast in Egypt. Comparative translation of the stone assisted in understanding many previously undecipherable examples of hieroglyphics.

Puzzle: What is the Nuclear Correction 11 Charged Lepton DIS Fixed Target DIS g /Z some caveats … correlated errors Depends on nuclear corrections W  Neutrino DIS Propagation of ° / W thru nuclei

… the motivation for nCTEQ 12 isospin DGLAP violation??? violation quark-gluon saturation resummation Fermi plasma motion QCD hi-x QED communication Nuclear Proton PDFs PDFs e.g. flavor low-Q 2 differentiation jet quenching target mass higher twist corrections non-linear QCD shadowing T.J. Hobbs Data from nuclear targets play a key T. Jezo, role in the flavor differentiation C. Keppel, M. Klasen K. Kovarik A Kusina, nCTEQ J. Morfin, F. Olness J. Owens, I. Schienbein, nuclear parton distribution functions J. Yu

13 … not just Nuclear PDFs

Nuclear PDFs are ESSENTIAL for proton PDFs 14 Neutrino DIS neutrino DIS m - m + n m s c N Depends on X nuclear Differentiate flavors of free-proton PDFs: corrections NNPDF Collaboration d=10 ~ 1 ¾ Eur.Phys.J. C77 (2017) 10, 663 distance Nuclear Correction Factor “... for the time being it is still appears advantageous to retain nuclear target data in the global dataset for general-purpose PDF determination”

15 Nuclear PDF The Players The Ingredients

… selected NLO Nuclear PDF Fits 16 isospin nPDFs violation quark-gluon Fermi plasma motion nuclear parton distribution functions Nuclear HKN'07: Hirai, Kumano, Nagai PDFs [PRC 76, 065207 (2007)] jet DSSZ'11: de Florian, Sassot, Stratmann, Zurita quenching target mass [PRD 85, 074028 (2012)] corrections shadowing nCTEQ'15: nCTEQ Collaboration [PRD 93, 085037 (2016)] EPPS’16: Eskola, Paakkinen, Paukkunen, Salgado Eur.Phys.J. C77 (2017) no.3, 163 TUJU'19: Tubingen & Jyvaskyla [Walt, Helenius, Vogelsang Phys. Rev. D 100, 096015 (2019)] nNNPDF2.0: NNPDF Collaboration [Khalek, Ethier, Rojo, van Weelden arXiv:2006.14629 (2020)]

17 Data sets & cuts for nPDF fits NC DIS & DY DIS Cuts: SLAC E-139 & E-049 nCTEQ: Q>2.0 & W>3.5 N = (D, Ag, Al, Au, Be,C, Ca, Fe, He) EPPS16: Q>2.0 & W>3.5 EPS09: Q>1.3 CERN BCDMS & EMC & NMC HKN: Q>1.0 N = (D, Al, Be, C, Ca, Cu, Fe, Li, Pb, Sn, W) DSSZ: Q>1.0 DESY Hermes N = (D, He, N, Kr) nCTEQ15: 740 data points HKN: 1241 data points FNAL E-665 EPS09: 929 data points N = (D, C, Ca, Pb, Xe) EPPS16: 1811 data points FNAL E-772 & E-886 N = (D, C, Ca, Fe,W) Q cut Neutrino DIS * NuTeV CHORUS CCFR & NuTeV N = Pb & Fe + LHC Pion Production: dijet, W/Z W cut RHIC: PHENIX & STAR N = Au will show comparision w/ LHC pPb proton vs nuclear: fewer data and more DOF … impose assumptions on nPDFs

Nuclear PDFs: DIS, DY, ¼ Prod, (new) Di-Jet 18 A=2 m u ! i t ! i ! r a T t a D r o r r i e i A=207 M l c u N All nuclear A values … expand our knowledge of nuclear A dimension

Selected Nuclear PDFs 19 g

20 some details ...

Mechanics of nPDFs 21 1) Multiplicative nuclear correction factors (HKN, EPPS, DSSZ) … for example HKN EPS 2) Generalized A-parameterization (nCTEQ) A=2 A=207 All nuclear A values Proton Nuclear use proton as a Boundary Condition

nCTEQ15 A-Dependence 22 u v e gluon c ? i t ? t a ? D L C Q Deuteron Correction : o r D r o C t o n T t a u t e r x o D - p i m h CJ15 i t a Proton Nuclear use proton as a Boundary Condition

23 Isospin Symmetry used to relate PDFs S u N ! ! o ! a B t Neutron a Proton d Isospin “New” Photon Anti- Anti- PDFs Proton Neutron proton neutron Isospin terms are comparable to NNLO QCD d u u d QCD & EW Corrections u d do NOT factorize A Review of Target Mass Corrections. Ingo Schienbein et al, J.Phys.G35:053101,2008.