QCD Evolution 2018

May 20, 2018, 8:00 AM → May 24, 2018, 5:40 PM US/Mountain

Drury Plaza Hotel

The 2018 QCD Evolution Workshop will take place May 20-24, 2018 in at the Drury Plaza Hotel in Downtown Santa Fe, NM. In a few short years since its inception in 2011, the QCD Evolution Workshop has rapidly grown to be the premier scientific meeting where advances in the exploration of the internal structure of the nucleon are reported. This workshop brings together senior researchers, postdoctoral fellows and talented graduate students to discuss the exciting recent developments and future directions in nuclear science. The purpose of the QCD Evolution Workshop is to summarize the accomplishments and provide guidance for the community effort in the areas of Transverse Momentum Distributions (TMDs), Generalized Parton Distributions (GPDs), small-x physics and Soft Collinear Effective Theory (SCET). The theory is closely tied to experiments at the leading nuclear and particle physics facilities in the US and abroad, such as the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab, the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Lab and the Large Hadron Collider (LHC) complex at CERN. The workshop is also central to the planning of the next-generation nuclear physics facility in the US, such as the Electron Ion Collider (EIC).

To request an invitation letter, please contact cnls-conferences@lanl.gov as soon as possible.

Organizing Committee:

Ian Balitsky
Alexei Prokuidin
Martha Constantinou
Anatoly Radyushkin
Leonard Gamberg
Christopher Lee
Duff Neill
Matt Sievert
Ivan Vitev (chair)
Shinsuke Yoshida

Sunday, May 20

8:00 AM Breakfast

Session 1

Convener: Dr Ivan Vitev (LANL)

1 Welcome

Speaker: Dr Ivan Vitev (LANL)

Slides QCD_Evo_18New_Vitev.pptx

2 Collinear QCD as a starting point

Speaker: Piet Mulders (Vrije Universiteit Amsterdam, NIKHEF)

Slides 2018-QCDevolution-Mulders.pdf

3 First extraction of transversity from a global analysis of data on lepton-hadron scattering and hadronic collisions

We present the first extraction of the transversity distribution based on the global analysis of pion-pair production in deep-inelastic scattering and in proton-proton collisions with one transversely polarized proton. The extraction relies on the knowledge of di-hadron fragmentation functions, which are taken from the analysis of electron-positron annihilation data. For the first time, the chiral-odd transversity is extracted from a global analysis similar to what is usually done for the chiral-even spin-averaged and helicity distributions. The knowledge of transversity is important among other things for detecting possible signals of new physics in high-precision low-energy experiments.

Speaker: Dr Marco Radici (University of Pavia)

Slides radici.pdf

4 TMDs in proton-proton collisions

Speaker: Maarten Buffing (UCLA)

Slides Buffing_2018_05(may)_20_Santa_Fe.pdf

10:10 AM Coffee Break

Session 2

Convener: Prof. Leonard Gamberg (Penn State Berks)

5 Double-scale evolution: consequences and ambiguities

Speaker: Alexey Vladimirov (Regensburg University)

Slides Vladimirov.pdf

6 Phenomenology of TMDs

The formulation of transverse momentum dependent distributions derived from the factorization of differential cross section allows a systematical analysis of polarized distributions. We consider in particular the case of twist-3 distributions and explore the properties in the matching with their collinear integrated parton distributions.

Speaker: Alexei Prokudin (JLab)

Slides prokudin_qcd_evolution18.pdf

7 Extract hadron's partonic structure from lattice QCD calculations

Speaker: Dr Jianwei Qiu (Jefferson Lab)

Slides Qiu_Evolution.pdf

12:00 PM Lunch

Session 3

Convener: Alexei Prokudin (JLab)

8 Power corrections to TMD factorization for particle production

A typical factorization formula for production of a particle with a small transverse momentum in hadron-hadron collisions is given by a convolution of two TMD parton densities with cross section of production of the final particle by the two partons. For practical applications at a given transverse momentum, though, one should estimate at what momenta the power corrections to the TMD factorization formula become essential. In this talk I present the results of calculation of first power corrections to TMD factorization formula for Z-boson production and Drell-Yan process in high-energy hadron-hadron collisions. At the leading order in $N_c$ power corrections are expressed in terms of leading power TMDs by QCD equations of motion.

Speaker: Prof. Ian Balitsky (JLab/ODU)

Slides QCDEV18BAlitsky.pdf

9 All-opacity gluon spectrum for jet physics at the EIC

Speaker: Dr Matthew Sievert (Brookhaven National Laboratory)

Slides Sievert_QCD_Evolution_2018.pdf

10 Semi-inclusive Kaon production at low scales

Speaker: Mr Juan Guerrero (Hampton University/Jefferson Lab)

Slides QCDEvo_2018_Juan_Guerrero.pdf

3:30 PM Coffee Break

Session 4

Convener: Dr Matthew Sievert (Brookhaven National Laboratory)

11 TMDs at small-x: an operator treatment

Speaker: Prof. Yuri Kovchegov (The Ohio State University)

Slides SantaFe18Kovchegov.pdf

12 When gluons go odd: how classical gluon fields generate odd azimuthal harmonics for the two-gluon correlation function in high-energy collisions

Speaker: Dr Vladimir Skokov (Western Michigan University)

Slides Skokov_QCDEvo18.pdf

13 Inclusive prompt photon production in e + A DIS at small x as a probe of gluon saturation

We present a first computation of the differential cross-section for in- clusive prompt-photon production in DIS to next-to-leading order (NLO) in αS at small-x within the framework of the Color Class condensate (CGC) [1]. The computation is performed to next-to-leading-log x (NLLx) accuracy and resums all higher twist contributions within the CGC effec- tive theory. Our work is within the same framework developed for p+A collisions and provides insight into such higher order computations in hadron-hadron collisions [3]. We observe that our result is sensitive to all- twist dipole and quadrupole fundamental Wilson-line correlators in the nucleus. In the leading twist limit, we obtain the k⊥ and collinear fac- torized expressions which match the dominant NLO and NNLO small x perturbative QCD contributions. In particular, our result in the collinear limit is directly proportional to the nuclear gluon distribution. In the soft photon limit, we extract the NLO cross-section for inclusive DIS and compare these to existing results [2] in the literature.

Speaker: Kaushik Roy (Stony Brook University)

Slides QCDEvolution2018_KRoy.pdf

6:00 PM Reception

Monday, May 21

8:00 AM Breakfast

Session 5

Convener: Dr Jianwei Qiu (Jefferson Lab)

14 Nucleon 3D imaging and science program with the 12 GeV Upgrade

Speaker: Latifa Elouadrhiri (Jefferson Lab)

Slides QCD-EVO2018-Laifa.pptx

15 Large transverse momentum in semi-inclusive deeply inelastic scattering beyond the lowest order

Speaker: Nobuo Sato (UConn)

Slides slides.pdf

16 Heavy quark jet substructure

Speaker: Dr varun vaidya (LANL)

Slides QCDevol2018Varun.pdf

10:00 AM Coffee Break

Session 6

Convener: Dr Sylvester Joosten (Temple University)

17 Lepton angular distributions in Drell-Yan process

High precision data of dilepton angular distributions in ??/Z production were reported recently by the CMS and ATLAS Collaboration covering a broad range of the dilepton transverse momentum, qT, up to ?300GeV. Pronounced qT dependencies of the ? and ? parameters, characterizing the cos2? and cos2? angular distributions, were found. Violation of the Lam?Tung relation was also clearly observed. We show that the qT dependence of ? allows a determination of the relative contributions of the q-qbar annihilation versus the qG Compton process. The violation of the Lam?Tung relation is attributed to the presence of a non-zero component of the q ?qbar axis in the direction normal to the ?hadron plane? formed by the colliding hadrons. The magnitude of the violation of the Lam?Tung relation is shown to reflect the amount of this ?non-coplanarity?. The observed qT dependencies of ? and ? from the CMS and the earlier CDF data can be well described using this approach. Implications on the extraction of the Boer-Mulders function and other hard processes at fixed-target and collider experiments will also be discussed.

Speaker: Jen-Chieh Peng (University of Illinois at Urbana-Champaign)

Slides Santa_Fe_Peng_2018.pdf

18 Measurements of light-quark hadronization in e+e- annihilation

Speaker: Gunar Schnell (University of the Basque Country)

Slides QCD_Evolution_2018_-_Gunar_Schnell(2).pdf

19 COMPASS spin program: recent results and plans

Speaker: Bakur Parsamyan (CERN)

Slides Parsamyan_QCDe2018.pdf

12:00 PM Lunch

Session 7

Convener: Piet Mulders (Vrije Universiteit Amsterdam, NIKHEF)

20 Lambda production in electron-positron annihilation

Speaker: Dr Marc Schlegel (University of Tubingen)

Slides QCD_Evolution_2018_Schlegel.pdf

21 Polarized TMDs, twist-3 functions, and the CSS formalism

Speaker: Daniel Pitonyak (Penn State Berks)

Slides Pitonyak_QCD_Evo_2018.pdf

22 Color unwound — Glauber gluons and factorisation in azimuthal asymmetries in Drell-Yan

Speaker: Jonathan Gaunt (CERN)

Slides QCDevolution_Gaunt.pdf

3:30 PM Coffee Break

Session 8

Convener: Dr Matthew Sievert (Brookhaven National Laboratory)

23 Progress on Pion Parton Distribution Functions from Hadronic Lattice Cross Sections

Speaker: Dr David Richards (Jefferson Lab)

Slides richards2018.pdf

24 SIDIS in Wandzura-Wilczek-type approximation

Speaker: Saman Bastami (University of Connecticut)

Slides QCD_Evolution_2018.pdf

25 Twist-3 Generalized Parton Distributions

Twist-3 Generalized Parton Distributions (GPDs) may provide an alternative source of information on quark orbital angular momentum. Additionally, twist-3 GPDs embody information on the spatial distribution of quark-gluon correlations. Spectator models are used to study general features that appear in twist-3 GPDs. We find in 1 loop calculations/spectator models that twist-3 generalized parton distributions exhibit discontinuities. In the forward limit these singular contributions grow into delta function contributions. These terms are essential for certain sum rules for twist 3 PDFs and neglecting these terms leads to an apparent violation of these sum rules. We identify these delta function terms with momentum components in the nucleon state that do not scale as the nucleon is boosted to infinite momentum.

Speaker: Fatma Aslan (NMSU)

Slides Fatma-QCD_SANTA_FE_2018.pdf

Tuesday, May 22

8:00 AM Breakfast

Session 9

Convener: Dr David Richards (Jefferson Lab)

26 Lattice Calculation of PDF from LaMET at Physical Pion Mass with Large Nucleon Momentum

We present a lattice-QCD calculation of the unpolarized isovector parton distribution func- tion (PDF) using ensembles at the physical pion mass with the large proton boost momentum Pz ? {2.2, 3.0} GeV within the framework of large-momentum effective theory (LaMET). In contrast with our previous physical-pion PDF result, we increase the statistics significantly, double the boost momentum, increase the investment in excited-state contamination systematics, and switch to a different operator for the quasi-PDF to avoid mixing with scalar matrix elements. We used four source-sink separations in our analysis to control the systematics associated with excited-state contamination. The one-loop LaMET matching corresponding to the new operator is calculated and applied to our lattice data. We detail the systematics that affect PDF calculations, providing a guide such that future calcula- tions can further improve on the precision of lattice PDF. We find our final parton distribution in reasonable agreement with the PDF provided by the CT14 global analysis.

Speaker: Yong Zhao (Massachusetts Institute of Technology)

Slides qcd2017_yzhao.pdf

27 Contributions of up and down quarks to TMD observables from Lattice QCD

Speaker: Michael Engelhardt (New Mexico State University)

Slides engelhardt.pdf

10:00 AM Coffee Break

Session 10

Convener: Michael Engelhardt (New Mexico State University)

28 Evolution of pseudo-PDFs

We discuss the structure of parton pseudo-distributions, their evolution and relation to parton quasi-distributions.

Speaker: Anatoly Radyushkin (ODU/JLab)

Slides Radyushkin_QCD_EV18.pdf

29 Pseudo Distributions from Lattice QCD

The Direct calculation of x-dependent parton distribution functions (PDFs) are not possible using ab initio Euclidean-space Lattice QCD, due to their definitions in terms of light-cone coordinates. I present the recent Lattice QCD calculation of pseudo PDFs, a Lorentz invariant generalization of light cone PDFs. These Lorentz invariant functions can be calculated on a Euclidean lattice and related to light cone PDFs in the proper limits. I will discuss the applicability of perturbative formula to the lattice data. I will also discuss methods of extracting the PDF from lattice data over a limited range of momenta and Euclidean-space separations.

Speaker: Joseph Karpie (College of William and Mary)

Slides QCD_Evo_(2018)_Pseudo-PDFs_on_the_LatticeKArpie.pdf

30 Nuclear Quark and Gluon Structure from Lattice QCD

Speaker: Michael Wagman (MIT)

Slides Wagman_QCD_Evolution_2018.pdf

12:00 PM Lunch

6:00 PM Workshop Dinner

Wednesday, May 23

8:00 AM Breakfast

Session 11

Convener: Jen-Chieh Peng

31 TMD sensitive jet observables

Speaker: Dr Felix Ringer (Los Alamos National Laboratory)

Slides QCDEV18_FRinger.pdf

32 Jet substructure measurements at the LHC and EIC

In this talk, I will develop the theoretical framework of jet substructure measurements in the semi-inclusive jet production. The talk will mainly be focused on the recent work on jet mass measurements, with and without grooming, as a particular substructure of interest. I will discuss factorization, nonperturbative effects, and joint resummations of several classes of logarithmic corrections to all orders. Then I will discuss how both ungroomed and groomed results give very good agreement with the available data from the LHC. I will also discuss some preliminary results on the jet measurements with and without substructures for the EIC.

Speaker: Kyle Lee (Stony Brook University)

Slides QCDEvol18Lee.pdf

33 The E906/SeaQuest Fixed-Target Dimuon Experiment at Fermilab: Recent Results and Prospects

Speaker: Kun Liu (LANL)

Slides 2018_QCD_Evo_Workshop.pdf

10:00 AM Coffee Break

Session 12

Convener: Christopher Lee (Los Alamos National Laboratory)

34 Inverting the mass hierarchy of jet quenching effects with prompt b-jet substructure

The mass of heavy quarks, such as charm and bottom, plays an important role in the formation of parton showers. This effect is apparently not well understood when parton showers evolve in a strongly interacting quark-gluon plasma. We propose a new experimental measurement in relativistic heavy ion collisions, based on a two-prong subjet structure inside a reconstructed heavy flavor jet, which can place stringent constraints on the mass dependence of in-medium splitting functions. We identify the region of jet transverse momenta where parton mass effects are leading and predict a unique reversal of the mass hierarchy of jet quenching effects in heavy ion relative to proton collisions. Namely, the momentum sharing distribution of prompt $b$-tagged jets is more strongly modified in comparison to the one for light jets. Our work is useful in guiding experimental efforts at the Large Hadron Collider and the Relativistic Heavy Ion Collider in the near future.

Speaker: Mr Haitao Li (LANL)

Slides haitao_QCD_evolution.pdf

35 Quarkonium production at low transverse momentum with NRQCD+SCET

We consider the transverse momentum spectrum of quarkonium produced in hadronic collisions. For traverse momentum parametrically smaller compared to its mass, in the central rapidity region, the quarkonium is produced nearly at rest and other particles in the event can only be soft and/or collinear along the beam direction. We use non-relativistic QCD (NRQCD) to describe the dynamics of the heavy quark antiquark pair where the light degrees of freedom are incorporated through soft collinear effective theory (SCET). We investigate the unpolarized cross section as well as the transverse single spin asymmetry (TSSA) for the initial state hadrons.

Speaker: Yiannis Makris (LANL)

Slides Yiannis-2018-QCDevol.pdf

36 Transverse Force Tomography

Speaker: Prof. Matthias Burkardt (NMSU)

Slides Evolution18Burkardt.pdf

12:00 PM Lunch

Session 13

Convener: Prof. simonetta liuti (university of virginia)

37 Exploring the twist-3 structure of hadrons

Speaker: Ignazio Scimemi (Universidad Complutense Madrid)

Slides Scimemi-QCDEvolution-2018.pdf

38 Quarkonium production: from JLab to an EIC

Speaker: Dr Sylvester Joosten (Temple University)

Slides 20180523-QCDEV2018-Quarkonium-JLab-EIC.pdf

39 Cold QCD at RHIC: Recent Results and Prospects

Speaker: Oleg Eyser (Brookhaven National Lab.)

Slides 2018-05-23_RHICcoldQCD_v1Eyser.pdf

3:30 PM Coffee Break

Session 14

Convener: Dr Shinsuke Yoshida (Los Alamos)

40 (Towards a quantitative study of) Flavour Effects on the determination of the W Mass

I will present a brief summary of previous studies estimating the size of theoretical uncertainties for the determination of the W mass, and I will show recent updates including flavour-dependent TMD effects.

Speaker: Giuseppe Bozzi (Università degli Studi di Pavia)

Slides Bozzi.pdf

41 Examining semi-inclusive electron-positron annihilation at large transverse momentum

Speaker: Eric Moffat (Old Dominion University)

Slides MoffatQCDEv2018.pdf

Thursday, May 24

8:00 AM Breakfast

Session 15

Convener: Prof. Gary Goldstein (Tufts University)

42 Accessing gluon TMDs in heavy quarkonium production at EIC

Speaker: Asmita Mukherjee (IIT Bombay)

Slides QCDEvolution18Asmita.pdf

43 Energy-momentum tensor, forces in the nucleon, and applications

Speaker: Peter Schweitzer (University of Connecticut)

Slides Talk-Schweitzer-7-QCD-evol-2018c.pdf

44 The QCD Energy Momentum Tensor in Spin 0, 1/2, and 1 Systems

Speaker: Prof. simonetta liuti (university of virginia)

Slides liuti_QCD18.pptx

10:00 AM Coffee Break

Session 16

Convener: Markus Diehl

45 Collinear factorization and intrinsic transverse momentum in low-energy Drell-Yan

In this talk, we discuss the transverse momentum distribution of Drell-Yan lepton pairs in fixed-target Drell-Yan experiments. We show that fixed-order theory underestimates data at large qT, by an amount that cannot be explained by perturbative truncation errors nor PDF uncertainties. We consider a modification of the standard collinear formalism that includes the effect of intrinsic transverse momentum also at large qT. This is intended to parametrize possible higher-twist effects which are presently not under theoretical control.

Speaker: Fulvio Piacenza (Pavia University)

Slides Piacenza_QCDevo2018.pdf

46 A numerical study of TMDs using Ogata's formula

Twist-3 Generalized Parton Distributions (GPDs) may provide an alternative source of information on quark orbital angular momentum. Additionally, twist-3 GPDs embody information on the spatial distribution of quark-gluon correlations. Spectator models are used to study general features that appear in twist-3 GPDs. We find in 1 loop calculations/spectator models that twist-3 generalized parton distributions exhibit discontinuities. In the forward limit these singular contributions grow into delta function contributions. These terms are essential for certain sum rules for twist 3 PDFs and neglecting these terms leads to an apparent violation of these sum rules. We identify these delta function terms with momentum components in the nucleon state that do not scale as the nucleon is boosted to infinite momentum.

Speaker: Terry John (UCLA)

Slides PresentationTerry.pdf

47 Twist-2 transverse momentum distributions at NNLO in QCD

The factorization theorem for DY and semi-inclusive DIS holds for all leading twist transverse momentum distributions. However a QCD perturbative calculation shows several important characteristics of spin-dependent distributions. We consider all the different spin-dependent distributions which can be matched onto integrated twist-2 functions, focusing on the Helicity, Transversity and Pretzelosity distributions. The pretzelosity case is specially relevant because, using a direct perturbative calculation at one loop, we obtain a null result which agrees with the experimental measurements. We show the complete set results of the matching at NLO and the results focusing on Transversity and Pretzelosity at NNLO.

Speaker: Daniel Gutierrez-Reyes (Universidad Complutense de Madrid)

Slides QCDEV2018_DGR_.pdf

12:00 PM Lunch

Session 17

Convener: Gunar Schnell (University of the Basque Country)

48 The Physics Program at the Future Electron-Ion Collider at BNL

Speaker: Matthias Perdekamp (UIUC)

Slides eRHIC-mgp.ppt

49 Realizing the Electron-Ion Collider at Jefferson Lab

Speaker: Dr Markus Diefenthaler (Jefferson Lab)

Slides Diefenthaler-QCDEvolution2018.pdf

50 Gluon transversity and top pair production spin correlations

Gluon fusion is the primary source of top-antitop pair production at the LHC. The spin dependences of proton gluon distributions impact the spin correlations of the top pairs. Decays of top pairs through different channels produce a variety of correlations among the decay products - single particles and jets. Combinations of the gluon distributions, either polarized or unpolarized, can be accessed experimentally through the kinematics of angular dependences of decay products.

Speaker: Prof. Gary Goldstein (Tufts University)

Slides QCD_Evol2018_Goldstein.pdf

3:30 PM Coffee Break

Session 18

Convener: Alexei Prokudin (JLab)

51 Probing the seaquark sivers function with the E1039 polarized Drell-Yan experiment

Speaker: Xuan Li (LANL)

Slides QCD_Evolution_2018_XuanLi_v4.pdf

52 Single transverse-spin asymmetry in polarized lambda production

Speaker: Dr Shinsuke Yoshida (Los Alamos)

Slides QCDevo2018_yoshida.pptx

53 Theory developments for double parton scattering

Speaker: Markus Diehl (DESY)

Slides diehl-evolution.pdf

5:30 PM Adjournment