Spatial and Momentum Tomography of Hadrons and Nuclei INT-17-3 Program (2017) - Seattle

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1 Spatial and Momentum Tomography of Hadrons and Nuclei INT7 Program (17) - Seattle

2 s r, NC i Reduced Cross Section parton density Bj =.8, i=15 Bj =.13, i= Bj =.5, i=16 - HERAPDF. e + p NLO Bj =.5, i=1 Bj =.8, i= Bj =.13, i=19 Bj =., i=18 Bj =.3, i=17 HERAPDF. e p NLO s r, NC i 6 Bj =.5, i=1 Bj =.8, i= 7 HERA NC e p.4 fb 1 HERA NC e + p.5 fb 1 Ös = 318 GeV Fied Target H1 and ZEUS Bj =.13, i=19 Bj =., i=18 Bj =.3, i=17 Bj =.5, i=16 Bj =.8, i=15 Bj =.13, i=14 Bj =., i=13 Bj =.3, i=1 Bj =.5, i=11 Bj =.8, i= Bj =.13, i=9 Bj =., i=8 H1 and ZEUS Differential cross section: ds e ± p ddq = pa Y + Q 4 s r,q ( ) Proton PDFs from HERA HERA NC e p.4 fb 1 HERA NC e + p.5 fb 1 Ös = 318 GeV Fied Target HERAPDF. e p NLO HERAPDF. e + p NLO Bj =.3, i=7 Bj =.5, i=6 Bj =.8, i=5 Bj =.13, i=4 Bj =.18, i=3 Bj =.5, i= Bj =.4, i=1 Bj =.65, i= Resolution (Q / QGeV / ) What we Know: Etensive program carried at HERA F precisely measured in a large- range At low- gluons dominate Reduced cross section: s r (,Q ) = F (,Q ) - y Y F + L(,Q ) INT7 Program S. Fazio (BNL)

3 Inclusive DIS on e+a analog to e+p: Nuclear Structure Functions quark+anti-quark Theory/models have to be able to describe the structure functions and their evolution gluons (or tag on F -charm) Ratio: F (,Q ) Pb /F (,Q ) p DGLAP: predicts Q but not A-dependence and -dependence Saturation models: predict A-dependence and -dependence but not Q Need: large Q lever-arm for fied, A-scan Aim at etending our knowledge on structure functions into the realm where gluon saturation effects emerge different evolution INT7 Program S. Fazio (BNL) 3

4 Electron-Ion Collider s Phase Space An EIC at its highest etends kinematic coverage for e+a data by a decade in at a fied Q by a decade in Q at a fied INT7 Program S. Fazio (BNL) 4

5 Nuclear Modifications Present Knowledge Latest state-of-the-art npdf is EPPS16 K. J. Eskola, P. Paakkinen, H. Paukkunen, C. A. Salgado [Eur.Phys.J. C77 (17) no.3, 163] Replacing EPS9. Quark flavors are now separated includes latest LHC data Measure different structure functions in e+a constrain npdf EPPS16* functional form with less constraints (for gluons) in etrapolating for < data critical to study the impact of the high precision EIC data! What is the possible impact of an Electron-Ion Collider? EPS9 Ratio: g(,q ) Pb /g(,q ) p EPPS16 EPPS16* INT7 Program S. Fazio (BNL) 5

6 Reduced Cross Section & Structure Functions s r = F (,Q ) - y ( ) F L,Q y ( ) INT7 Program S. Fazio (BNL) 6 y ( ) = Y y Structure functions can be etracted from the reduced cross section Pseudo-data are generated using PYTHIA and according to EPS9 central values In order to etract F from the reduced cross section, we adopted the same method used at HERA [e.g. see HERMES paper on arxiv:13.574] F L etracted from the reduced cross section by fitting the slopes in Y + for different s at fied, Q requires running at (at least) three different c-o-m energies Simulation: e+au sample simulated using PYTHIA 5() GeV electrons X 5 GeV Au [ s = 3(63) GeV] > L = fb /A 5() GeV electrons X 75 GeV Au [ s = 39(78) GeV] > L = 4 fb /A 5() GeV electrons X GeV Au[ s = 45(89) GeV] >L = 4 fb /A Total simulated event sample (for each electron energy) L = fb /A

7 () σ )-log red (,Q e+au 1 Reduced Cross Section & F (e+au) = 3. = 5. = 8. = 1.3 =. = 3. = 5. = 8. - = =. - = 3. - = 5. - = 8. = =. = 3. = 5. Large epected impact on current theory Q (GeV ) uncertainty, especially at low- and low-q s = 31.6 GeV s = 44.7 GeV s = 89.4 GeV World Data (A Fe) CT14NLO+EPPS16 Ldt = fb /A ( ) - s r = F,Q Systematics = 3% Stat. and Sys. error summed in quadrature (Sys. dominate!) Gluon etraction via scaling violation dσ(,q )/dlnq (requires ~> 1 decade in Q at a fied ) Comparison of linear with nonlinear evolution in will signal saturation needs low- reach INT7 Program S. Fazio (BNL) 7 y ( ) F L,Q y ( ) An EIC at its highest energy provides a factor larger reach in Q and low- compared to available data

8 We look at photons radiated from the electron before or after the interaction energy of the radiative photon RadGamma_Energy_zoom Entries Mean.813 RMS.9658 Integral 3.619e E g 15 5 Radiated photons Polar angle of the radiative photon 3 5 RadGamma_Theta Entries Mean 3.83 RMS.911 Integral 4.586e q g Radiated photons are Low energy (most of them < 1 GeV) uniformly distributed in the azimuthal angle collinear to the scattered electron (q g > 3 rad) Correction factor: We use Django simulator including O(α) radiative effects Rc = s red s red ( ) ( ) ( O a ) Born 5% events radiate a photon INT7 Program S. Fazio (BNL) 8 Rc Radiative corrections - GeV GeV Q = 1.4 GeV Q = 4.4 GeV Q = 13.9 GeV Q = 43.9 GeV Q = GeV Q = GeV Q =.5 GeV Q = 7.8 GeV Q = 4.7 GeV Q = 78.1 GeV Q = 47 GeV Q = 781. GeV y

9 Etracting F L (e+au) Higher energy EIC: s = 63, 78, 89 GeV Enough Lever Arm required (three points, Y + >.) Errors still dominated by systematics (similarly for larger Q and lower energies) Fraction of statistical uncertainty over total uncertainty in measuring s r total error = stat. + sys. summed in quadrature assumed sys. = 3% Star error dominates only at large- and very large Q INT7 Program S. Fazio (BNL) 9

10 F L (e+au) )+C.7.6 e+au s = 63., 77.5, 89.4 GeV ò Ldt = fb /A s = 31.6, 38.7, 44.7 GeV CT14NLO+EPPS16 F L (,Q C= Q = 1.4 GeV C=.45 Q = 47 GeV C=.4 Q = 139 GeV C=.35 Q = 78 GeV C=.3 Q = 44 GeV C=.5 Q = 5 GeV C=. Q = 14 GeV C=.15 Q = 7.8 GeV C=.1 Q = 4.4 GeV C=.5 Q =.5 GeV Errors dominated by the systematics in the cross section measurement Not luminosity hungry! Study: fb fb has negligible impact (see backup slide) - 1 INT7 Program S. Fazio (BNL)

11 Novel probe! Charm production: a unique tool! Events Decay Kaon P(GeV) 1 s = 89.4 GeV Decay Kaon h We select kaons in the final state of the D meson decay, looking for: a displaced verte:.1 cm < Verte < 3 cm Momentum within the acceptance of an EIC model detector erhic) CENTRAL DETECTOR ( < h < 1) de/d ->. GeV < P <.8 GeV RICH -> GeV < P < 5 GeV Direct access to gluons at medium to high by tagging photon-gluon Helps determining heavy quarks mass scheme e+au - s = 89.4 GeV Decay Kaon verte radius (cm) Selection of charm-production events FORWARD (1 < h < 3.5) RICH -> GeV < P < 4 GeV INT7 Program S. Fazio (BNL) 11 DIS Charm decay e+au - REAR (.5 < h < ) RICH -> GeV < P < 15 GeV

12 ()/ )-log red (,Q cc σ Charm - reduced Cross Section & F (e+au) e+au =. = 3. = 5. = 8. 1 = 1.3 =. = 3. = 5. - = 1.3 = 8. - =. - = 3. - = 5. - = 8. Large epected impact on current theory uncertainty, in the whole range s = 31.6 GeV s = 44.7 GeV s = 89.4 GeV CT14NLO+EPPS16 Ldt = fb /A = 1.3 =. = 3. = 5. 3 Q (GeV ) INT7 Program S. Fazio (BNL) 1 4 Systematics = 7% Stat. and Sys. error summed in quadrature (Sys. dominate!) No world data eist! Large epected impact on current theory uncertainty, especially at low and low-q

13 )+C (,Q cc L F Charm - F L (e+au) Enough Lever Arm required (three points, y+ >.) e+au s = 63., 77.5, 89.4 GeV ò Ldt = fb /A s = 31.6, 38.7, 44.7 GeV CT14NLO+EPPS16 C= Q = 1.4 GeV C=.4 Q = 139 GeV C=.35 Q = 78 GeV C=.3 Q = 44 GeV C=.5 Q = 5 GeV C=. Q = 14 GeV C=.15 Q = 7.8 GeV C=.1 Q = 4.4 GeV C=.5 Q =.5 GeV Errors dominated by the systematics in the cross section measurement Not luminosity hungry! Study: fb fb has negligible impact (see backup slide) High energy EIC: huge impact on current predictions - 1 INT7 Program S. Fazio (BNL) 13

14 Charm selection: background & efficiency Background study We look at background from DIS events with kaons that pass the whole selection but are not coming from a charm decay. The fraction of background over signal events is: (selected bkg events) / (selected Charm Events) Conclusion: The B/S fraction is epected in the order of ~1% with a very light energy dependence Efficiency study We look at the efficiency of selection charm production events. The efficiency is defined as: (selected Charm Events) / (charm Events in Acceptance) Conclusion: The charm selection efficiency is epected in the order of ~8% with no significant energy dependence INT7 Program S. Fazio (BNL) 14

15 EIC: s = 3, 39, 45 GeV The EIC impact Fits to the EIC simulated data EPPS16* EPPS16 using a fleible function with a couple of etra free parameters at small for gluon (not for the quarks) valence EIC: s =63, 78, 89 GeV strange INT7 Program S. Fazio (BNL) 15

16 The EIC impact sea quarks Fits to the EIC simulated data EIC: s = 3, 39, 45 GeV EIC: s =63, 78, 89 GeV u-bar d-bar INT7 Program S. Fazio (BNL) 16

17 The EIC impact gluons Pb g R Red. factor low-energy scenario - - s = GeV Q = GeV 1 high-energy scenario Inclusive DIS alone has a huge effect at low- Charm has a dramatic effect at high- INT7 Program S. Fazio (BNL) 17

18 )+C F L (,Q e+au F L - EIC e+au s = 63., 77.5, 89.4 GeV ò Ldt = fb /A s = 31.6, 38.7, 44.7 GeV CT14NLO+EPPS16 C= Q = 1.4 GeV Proton SFs C=.45 Q = 47 GeV C=.4 Q = 139 GeV C=.35 Q = 78 GeV C=.3 Q = 44 GeV C=.5 Q = 5 GeV C=. Q = 14 GeV C=.15 Q = 7.8 GeV C=.1 Q = 4.4 GeV C=.5 Q =.5 GeV F L Proton F L - HERA HERAPDF1.5 NNLO CT NNLO MSTW8 NNLO H1 and ZEUS 98.6 Q 184 H1 ABM1 NNLO NNPDF.3 NNLO JR9 NNLO ZEUS 3 [GeV ] - 1 Not only for nuclei! Comparable precision for proton Structure Functions in e+p scattering, to even higher Q at high Beyond what HERA achieved: precise measurement of proton F L INT7 Program S. Fazio (BNL) 18

19 Proton PDFs Therefore EIC can have large impact on proton PDFs too! e+deutrium data are sensitive to u/d quark flavor separation (need to correct for nuclear modifications) Electroweak data allow to constrain s quark PDFs as well as SIDIS +FF INT7 Program S. Fazio (BNL) 19

20 Conclusions e+a physics program at a future Electron-Ion Collider provides an unprecedented opportunity to study quarks and gluons in nuclei Precise measurements of nuclear structure functions in a large phase-space Constrain gluon npdfs at large- by tagging photon-gluon fusion through precise measurements of charm production Large impact in constraining gluon npdfs at low- Same or better precision epected for proton SFs too, Plus constraining large gluons and separate u/d/s flavors This is day 1 high impact physics! Recent publication: E.C. Aschenauer, S. F., M.A.C. Lamont, H. Paukkunen, P. Zurita [arxiv: ] INT7 Program S. Fazio (BNL)

21 INT7 Program S. Fazio (BNL) 1

22 ) F L (,Q Ldt = fb /A e+au: s = 63., 77.5, 89.4 GeV 3 Q = 1.4 GeV Q = 7.8 GeV Q = 43.9 GeV Only at erhic Q =.5 GeV Q = 13.9 GeV Q = 4.4 GeV Q = 4.7 GeV 1 ) (,Q cc L F Ldt = fb /A e+au: s = 63., 77.5, 89.4 GeV 3 Q = 1.4 GeV Q = 7.8 GeV Q = 43.9 GeV Only at erhic Q =.5 GeV Q = 13.9 GeV Q = 4.4 GeV Q = 4.7 GeV 1 ) F L (,Q ) F L (,Q Ldt = fb /A e+au: e+au: s = 31.6, 38.7, 44.7 GeV Ldt = fb /A 3 3 Q = 1.4 GeV Q = 7.8 GeV Q = 43.9 GeV Q = 1.4 GeV Q = 7.8 GeV Q = 43.9 GeV s = 31.6, 38.7, 44.7 GeV Q =.5 GeV Q = 13.9 GeV Available at erhic and JLEIC Q =.5 GeV Q = 13.9 GeV Available at erhic and JLEIC Q = 4.4 GeV Q = 4.7 GeV Q = 4.4 GeV Q = 4.7 GeV 1 1 ) (,Q cc L F ) (,Q cc L F Ldt = fb /A e+au: e+au: s = 31.6, 38.7, 44.7 GeV Ldt = fb /A 3 3 Q = 1.4 GeV Q = 7.8 GeV Q = 43.9 GeV Q = 1.4 GeV Q = 7.8 GeV Q = 43.9 GeV s = 31.6, 38.7, 44.7 GeV Q =.5 GeV Q = 13.9 GeV Available at erhic and JLEIC Q =.5 GeV Q = 13.9 GeV Available at erhic and JLEIC Q = 4.4 GeV Q = 4.7 GeV Q = 4.4 GeV Q = 4.7 GeV 1 1 INT7 Program S. Fazio (BNL)

23 ) (GeV Q 3 Fraction of Statistical Uncertainty e+au s = 31.6 GeV Ldt = fb /A Sys. unc. = 1.6 % (%) stat / tot ) (GeV Q 3 Fraction of Statistical Uncertainty e+au s = 44.7 GeV Ldt = 4 fb /A Sys. unc. = 1.6 % (%) stat / tot ) (GeV Q 3 1 Fraction of Statistical Uncertainty e+au s = 89.4 GeV Ldt = 4 fb /A Sys. unc. = 1.6 % (%) stat / tot INT7 Program S. Fazio (BNL) 3

24 Impact from and on p+a and A+A physics npdfs required as input to physics in A+A LHC has so far only moderate impact (see arxiv: ) on constraining npdfs LHC/RHIC coverage at rapidity y <1 Higher energy configurations of an EIC constrain npdfs in an -range critical for the A+A program at the LHC INT7 Program S. Fazio (BNL) 4