Jet measurements at the EIC

Felix Ringer Lawrence Berkeley National Laboratory

RHIC & AGS Annual users meeting, BNL — 10/22/2020 Introduction Inclusive and leading jets TMDs & CNM Conclusions The Electron-Ion Collider

January 9, 2020

• High luminosity 33 34 2 1 10 cm s • Center-of-mass energy ps = 20 140 GeV • Highly polarized beams • Electron-proton/nucleus collisions

… 2010 2015 2018 2020

2 Introduction Inclusive and leading jets TMDs Hadronization & CNM Conclusions The EIC science program

• The spin and mass of the proton • 3D imaging • Parton distribution functions Transverse momentum (TMDs) and position (GPDs)

1 1 = ⌃(Q2)+G(Q2)+L (Q2)+L (Q2) 2 2 q g 1 1 = ⌃(Q2)+G(Q2)+L (Q2)+L (Q2) ~ 2 2 q g

• Small-x and saturation • Hadronization • Nuclear modification in eA collisions

3 Introduction Inclusive and leading jets TMDs Hadronization & CNM Conclusions The EIC science program with jets

Jets as tools to realize the EIC science goals — Recent publications

• The spin of the proton, PDFs Hinderer, Schlegel, Vogelsang `15, `17, Abelof, Boughezal, Liu, Petriello `16, Boughezal, Petriello, Xing `18, Aschenauer, Chu, Page `19, Guzey, Klasen `18, `20, Borsa, Florian, Pedron `20, `20, Arratia, Furletova, Hobbs, Olness, Sekula `20

• 3D nucleon/nucleus tomography Zheng, Aschenauer, Lee, Xiao, Yin `18, Liu, FR, Vogelsang, Yuan `19, Gutierrez-Reyes, Scimemi, Waalewijn, Zoppi `19, Hatta, Mueller, Ueda, Yuan `19, Arratia, Kang, Prokudin, FR `20, Kang, Liu, Mantry, Shao `20, Castillo, Echevarria, Makris, Scimemi `20

• Saturation, a new form of matter Hatta, Xiao, Yuan `17, Salazar, Schenke `19, Roy, Venugopalan `19, Kang, Liu `19 Kolbe, Roy, Salazar, Schenke, Venugopalan `20

• Hadronization and and in the nucleus Klasen, Kovarik `18, Aschenauer, Lee, Page, FR `19, Qin, Wang, Zhang `19, Arratia, Song, FR, Jacak `19, Li et al. `20, Barata, Mehtar-Tani, Soto-Ontoso, Tywoniuk `20, Li, Vitev `20

4 Introduction Inclusive and leading jets TMDs Hadronization & CNM Conclusions The EIC science program with jets total number of EIC jet papers

• There have been many new developments recently! • Prominently featured in the EIC Yellow Report

5 Introduction Inclusive and leading jets TMDs Hadronization & CNM Conclusions Jets at the EIC

Jet transverse momentum Number of particles

Relatively low energies, need good control of hadronization corrections

Clean environment — no Multi Parton Interactions (MPI)

6 Introduction Inclusive and leading jets TMDs Hadronization & CNM Conclusions Jets at the EIC Q2 > 100 GeV2, ps = 89 GeV e 10

initial proton particle momentum initial proton

Struck Jets

Jets are excellent proxies of parton level kinematics Clean separation of current & target fragmentation (UE) Complementary to observables with

Arratia, Jacak, FR, Song `19 Laboratory frame Pythia 8 see also Aschenauer, Chu, Page `19 7 Introduction Inclusive and leading jets TMDs Hadronization & CNM Conclusions The QCD fragmentation process

• Fragmentation functions de Florian, Epele, Hernandez-Pinto, Sassot, Stratmann `15

10

pT = 100 GeV 8 )

• Jet functions R T 6 R =0.7 z,p (

g 4 J

2

Kang, FR, Vitev `16 0 Dai, Kim, Leibovich `17 0 0.2 0.4 0.6 0.8 1 Neill, FR, Sato `20 z = pT /pˆT 8 Introduction Inclusive and leading jets TMDs Hadronization & CNM Conclusions Outline

• Introduction • Inclusive and leading jets • TMDs measurements with jets • Hadronization and cold nuclear matter • Conclusions

9 Introduction Inclusive and leading jets TMDs Hadronization & CNM Conclusions Jet clustering and frame dependence

• Laboratory frame e0(k0) e(k) Can measure two variables 2 2 2 2 Q =(k k0) • Jet transverse momentum pT ,Q• Photon virtualitypT ,Q

2 Leading electronpT ,Q 2 pT ,Q

• Cluster jets in the laboratory frame ⌘, • Leading-order eq eq !

10 Introduction Inclusive and leading jets TMDs Hadronization & CNM Conclusions Jet clustering and frame dependence

e0(k0) • Laboratory frame e(k)

2 2 2 Measure only p T ,,Q close analogy to pp jet + X Q =(k k0) !

NLO NNLO 2 pT ,Q

Hinderer, Schlegel, Vogelsang `15 Abelof, Boughezal, Liu, Petriello `16

11 Introduction Inclusive and leading jets TMDs Hadronization & CNM Conclusions Jet clustering and frame dependence

e0(k0) • Laboratory frame e(k)

2 2 2 Measure only p T ,,Q close analogy to pp jet + X Q =(k k0) ! Double longitudinal spin asymmetries qi , g

2 ~e + p~ jet + X ~e + p~ e +jet+X pT ,Q ! !

NLO

Boughezal, Petriello, Xing `18 Borsa, Florian, Pedron `20 see also Hinderer, Schlegel, Vogelsang `17 12 Introduction Inclusive and leading jets TMDs Hadronization & CNM Conclusions Jet clustering and frame dependence Arratia, Makris, Neill, FR, Sato `20 • Breit frame

2 • Photon virtualitypT ,Q

• Jet energy

Inclusive jets Breit frame

ps = 63 GeV ,Q>10 GeV Pythia

NLL NP d ⌦ R =0.8

• Reconstruct jets which enclose the Breit frame beam axis • Starting point for Breit frame TMD-jet studies

13 Introduction Inclusive and leading jets TMDs Hadronization & CNM Conclusions

Leading jets Neill, FR, Sato `20

• Inclusive vs. leading jets • The average energy loss

R

z =1 z loss 1

14 + Introduction Inclusive and leadinge e jets TMDs Hadronization & CNM Conclusions Outline

• Introduction • Inclusive and leading jets • TMDs measurements with jets • Hadronization and cold nuclear matter • Conclusions

15 + Introduction Inclusive and leadinge e jets TMDs Hadronization & CNM Conclusions TMD-jet observables

Gutierrez-Reyes, Scimemi, Waalewijn, Zoppi `18, `19 • Semi-Inclusive Deep Inelastic Scattering Gutierrez-Reyes, Makris, Vaidya, Scimemi, Zoppi `20 • Breit frame jet reconstruction e + p e +jet+X !

dep eJX ! = H f (x, q) J (z,q,R) dQ2dxdzdq DIS q ⌦q q q X Perturbative TMD jet function

• Sensitivity to TMD PDF only • Winner-take-all (WTA) jet axis

16 + Introduction Inclusive and leadinge e jets TMDs Hadronization & CNM Conclusions TMD-jet observables

Gutierrez-Reyes, Scimemi, Waalewijn, Zoppi `18, `19 • Semi-Inclusive Deep Inelastic Scattering Gutierrez-Reyes, Makris, Vaidya, Scimemi, Zoppi `20 • Breit frame jet reconstruction

e + p e +jet+X !

WTA-axis

17 + Introduction Inclusive and leadinge e jets TMDs Hadronization & CNM Conclusions Electron-jet correlations Liu, FR, Vogelsang, Yuan `18, `20 Arratia, Kang, Prokudin, FR `19 e jet • Measure the electron-jet imbalance ~qT = p~T + p~T

• Sensitivity to TMD PDFs only

• Sivers asymmetry (S~ ) ( S~ ) T T ⌘

jet p~T

S~T e p ~qT e p~T ejet p~T

• Test of the predictive power of QCD — di-jet processes at RHIC 18 + Introduction Inclusive and leadinge e jets TMDs Hadronization & CNM Conclusions Electron-jet correlations - flavor sensitivity

e jet Liu, Kang, Mantry, Shao `20 • Measure the electron-jet imbalance ~qT = p~T + p~T

• and the jet charge Qi = Qh zQ Field, Feynman `78   ⌘ h h h h jet X X2 (weighted sum of charges)

• Jet charge tagging avoids large cancellation between different quark flavors (S~ ) ( S~ ) T T

jet p~T

S~T e p ~qT e p~T see also Krohn, Lin, Schwartz, Waalewijn `12, ejet Waalewijn `12, p~T 19 RHIC measurements + Introduction Inclusive and leading jets TMDs HadronizationeWe± & CNM Conclusions Outline

• Introduction • Inclusive and leading jets • TMDs measurements with jets • Hadronization and cold nuclear matter • Conclusions

20 + Introduction Inclusive and leading jets TMDs HadronizationeWe± & CNM Conclusions Probes of cold nuclear matter effects in eA

• Electron-jet correlations • Transverse momentum broadening

jet GW - Gyulassy Wang p~T Probability distribution

e p ~qT e p~T Barata, Mehtar-Tani, Soto-Ontoso, Tywoniuk `20 Liu, FR, Vogelsang, Yuan `18, `20, ejet Arratia, Jacak, FR, Song `19 p~T 21 + Introduction Inclusive and leading jets TMDs HadronizationeWe± & CNM Conclusions Probes of cold nuclear matter effects Li, Vitev `20 • Inclusive jet production e + A e +jet+X !

Medium modified jet function approach

µ med 2 med Jq (z,pT R, µ)= d k fq qg (z,k ) + ... z(1 z)p R ? ! ? "Z T #+

22 + Introduction Inclusive and leading jets TMDs HadronizationeWe± & CNM Conclusions Do we need to measure jets at the EIC? Neill `20 h • Evolve jet functions to a nonperturbative scale (~1 GeVD i~( ⇤ QCD ) • Small-z resummation + Local parton hadron duality • The only fitted parameter is the cutoff scale (& partly the normalization) Hi(pT )

pT R

h Di (⇤QCD)

23 + Introduction Inclusive and leading jets TMDs HadronizationeWe± & CNM Conclusions Do we need to measure jets at the EIC? Neill `20 h • Evolve jet functions to a nonperturbative scale (~1 GeVD i~( ⇤ QCD ) • Small-z resummation + Local parton hadron duality • The only fitted parameter is the cutoff scale (& partly the normalization) Hi(pT )

pT R

h Di (⇤QCD) … this suggests

• Hadrons are simply jets with a nonperturbative radius • The more fundamental objects are jets/jet functions • Most of the QCD fragmentation process is perturbative — do we still need fragmentation functions?

24 Introduction Inclusive and leading jets TMDs Hadronization & CNM Conclusions Outline

• Introduction • Inclusive and leading jets • TMDs measurements with jets • Hadronization and cold nuclear matter • Conclusions

25 Introduction Inclusive and leading jets TMDs Hadronization & CNM Conclusions Conclusions

• Growing field of jet physics at the EIC • Relevant for all parts of the EIC science program • Jet physics part of the EIC Yellow Report • Potential impact on detector design • Many new opportunities • STAR, sPHENIX, HERA

23-25 Nov

https://indico.bnl.gov/event/8066/overview

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