LC2019 - QCD on the light cone: from hadrons to heavy ions

Session

Plenary

16 Sept 2019, 09:30

Amphithéâtre Sophie Germain (Alan Turing Building)

Conveners

Plenary: Invited

• Cédric Lorcé (Ecole polytechnique)

Plenary: Invited

• Giovanni Salme (Istituto Nazionale di Fisica Nucleare)

Plenary

• Giovanni Salmè (Istituto Nazionale di Fisica Nucleare)

Plenary: Invited

• Jean-François Mathiot

Plenary: Invited

• Stanley Brodsky (SLAC National Accelerator Laboratory)

Plenary

• Stanley Brodsky (SLAC National Accelerator Laboratory)

Plenary: Invited

• Samuel Wallon

Plenary: Invited

• Cyrille Marquet (CPHT - Ecole Polytechnique)

Plenary

• Cyrille Marquet (CPHT - Ecole Polytechnique)

Plenary: Invited

• James Vary (Iowa State University)

Plenary: Invited

• Jean-Philippe Lansberg (IPN Orsay, Paris Saclay U. / IN2P3-CNRS)

Plenary

• Jean-Philippe Lansberg (IPN Orsay, Paris Saclay U. / IN2P3-CNRS)

Plenary: Invited

• Hervé Moutarde

Plenary: Invited

• Chueng-Ryong Ji (North Carolina State University)

Plenary: McCartor awardees

• Chueng-Ryong Ji (North Carolina State University)

96. Overview of GPDs

Paweł Sznajder (National Centre for Nuclear Research)

16/09/2019, 09:30

Hadronic structure

74. Energy-Momentum Tensor and Light Cone

Oleg Teryaev (JINR)

16/09/2019, 10:00

Hadronic structure

The QCD energy-momentum tensor (EMT) relation to light-cone distributions and correlators is considered. The limit of massless particles and pressure of quarks in photons is addressed. The special role of tensor polarization of spin-1 particles is analyzed. Special attention is payed to the role of EMT in coupling of quarks and gluons to gravity and manifestation of equivalence principle and...

68. An overview of baryon-to-meson Transition Distribution Amplitudes: basic properties, physical interpretation and experimental perspectives

Kirill Semenov-Tian-Shansky (PNPI)

16/09/2019, 11:00

Hadronic structure

Baryon-to-meson Transition Distribution Amplitudes (TDAs) appear as building blocks for amplitudes within the collinear factorized description of a class of hard exclusive reactions such as hard exclusive meson electroproduction off a baryon in the near-backward region and baryon-antibaryon annihilation into a meson and a lepton pair.

In this talk we present a general overview of the...

66. Bound states and Perturbation theory

Paul Hoyer (University of Helsinki)

16/09/2019, 11:30

Hadronic structure

QED bound states (atoms) are “non-perturbative” in the sense that no finite order Feynman diagram has a bound state pole. Wave functions are typically gauge dependent and exponential in $\alpha$. Physical binding energies on the other hand do have a perturbative expansion in $\alpha$ (and log $\alpha$). The hyperfine splitting of Positronium has been evaluated to O(${\alpha }^7$log$\alpha$) and...

31. Minkowski space approach to self-energies and scale invariance

Tobias Frederico (Instituto Tecnologico de Aeronautica)

16/09/2019, 11:55

Few- and many-body physics

In this contribution the solution of the Schwinger-Dyson equation in Minkowski space, for a QED-like theory with a massive vector, in Rainbow ladder approximation and using integral representation will be presented for the Feynman gauge and compared to Euclidean results with Pauli-Villars regulators. The unregulated equations have solution below the critical coupling constant $\alpha_c=...

39. Complex poles, spectral function and reflection positivity violation of Yang-Mills theory

Kei-Ichi Kondo (Chiba University)

16/09/2019, 12:20

QCD at finite temperature

We consider the analytic continuation of the gluon propagator from the Euclidean region to the complex momentum plane towards the Minkowski region. Then we derive general relationships between the number of complex poles of a propagator and the sign of the spectral function originating from the branch cut in the Minkowski region under some assumptions on the asymptotic behaviors of the...

99. Early stages of heavy-ion collisions

Francois Gelis

17/09/2019, 09:00

Small-x physics and heavy ions

Heavy ion collisions pose interesting challenges to quantum chromodynamics, because they probe the parton structure of the incoming nuclei at very small longitudinal momentum fractions. Combined with the large size of nuclei, this may lead to the phenomenon of gluon saturation. The Color Glass Condensate is an effective QCD description that aims to cope with such a situation. In this talk, I...

88. Review on heavy-ions@LHC and RHIC

Barbara Antonina Trzeciak (Utrecht University)

17/09/2019, 09:30

Small-x physics and heavy ions

The main goal of heavy-ion programs of the LHC and RHIC experiments is to characterise properties of the hot and dense QCD matter, so called quark-gluon plasma, created in the heavy-ion collisions and the phase transition between the hadronic and the de-confined matter.
In this review, recent experimental results of relativistic heavy-ion collisions at the top RHIC and LHC energies and their...

94. Can we create quark-gluon plasma in small colliding systems?

Maxime Guilbaud (CERN)

17/09/2019, 10:00

Small-x physics and heavy ions

Starting with the SPS and now RHIC and LHC, heavy-ion collisions (A-A) were used to study the quark-gluon plasma and its properties. Small colliding systems such as p-p and p-A were used as baseline to understand effects from vacuum QCD and cold nuclear effects respectively. Nevertheless since the discovery of quark-gluon plasma like signatures in small colliding systems (such as p-p, p-A,...

91. Improved opacity expansion for medium-induced parton splitting

Yacine Mehtar-Tani

17/09/2019, 11:00

QCD at finite temperature

Improved opacity expansion for medium-induced parton splitting

Medium-induced parton splitting is the building block for jet evolution in the presence of a hot QCD medium and plays a central role in quantitative studies of jet quenching. It exhibits two regimes: single hard and multiple soft scattering regimes that dominate at high and low frequency respectively. A closed analytic...

95. Small system physics and EIC

Michael A. Winn (Université Paris-Saclay (FR))

17/09/2019, 11:30

Small-x physics and heavy ions

70. Confinement in Nuclei and the Expanding Proton

Gerald Miller (University of Washington, Seattle )

17/09/2019, 12:00

Few- and many-body physics

High-precision knowledge of electromagnetic form factors of nuclei is a subject of much current experimental and theoretical activity in nuclear and atomic physics. Such precision mandates that effects of the non-zero spatial extent of the constituent nucleons be handled in a manner that goes beyond the usual impulse approximation. A series of simple, Poincare-invariant, composite-proton...

43. QCD at finite temperature and density from the Curci-Ferrari model

Urko Reinosa (CPHT - Ecole Polytechnique - CNRS)

17/09/2019, 12:25

QCD at finite temperature

We review recent progress in describing the equilibrium properties of QCD (and related theories such as Yang-Mills theory) at finite temperature/density from a systematic and controlled small parameter expansion, based on the Curci-Ferrari model. The latter has recently been proposed as a possible extension of the standard but ill-defined Faddeev-Popov action in the Landau gauge. In the case...

53. Overview of TMDs

Miguel Echevarria (INFN Pavia)

18/09/2019, 09:00

Hadronic structure

I will review the current status of transverse-momentum-dependent parton distribution and fragmentation functions (TMDs), which encode the 3-dimensional structure of the nucleon in momentum space. I will discuss their properties, how they are connected to different physical observables, and the state-of-the-art theoretical and phenomenological results.

69. Overview of small-x physics and TMDs

Tolga Altinoluk (National Centre for Nuclear Research)

18/09/2019, 09:30

Small-x physics and heavy ions

Inclusive particle production in forward pA collisions is one of the observables that is used frequently in order to understand the high-energy collision data. Moreover, at certain kinematics, one gets access to TMDs from the CGC calculations of these observables. I will discuss the details of this correspondence focusing on multi-jet production.

92. Overview of low-x experiments

Radek Zlebcik (Deutsches Elektronen-Synchrotron (DE))

18/09/2019, 10:00

Small-x physics and heavy ions

The LHC and HERA experimental results are reviewed with focus on the low-x kinematic domain where the BFKL dynamics, saturation effects and the gluon transverse momentum play a role.
In particular, diffractive processes (involving J/psi, upsilon or jets), the central exclusive production in the hadron-hadron collisions and the forward jets produced in pp and pA are discussed.

98. Overview of jet physics

Gregory Soyez (IPhT, CEA Saclay)

18/09/2019, 11:00

Jet physics

16. High energy scattering in QCD: from low to high Bjorken $x$

Jamal Jalilian-Marian (Baruch College)

18/09/2019, 11:30

Small-x physics and heavy ions

We propose and develop a new formalism that generalizes the Color Glass Condensate approach to high energy scattering by including both small and large $x$ gluons in the wave function of a target proton or nucleus. This allows one to treat particle production at both low and high transverse momenta on the same footing. We illustrate the formalism by calculating the differential cross section...

45. Beam spin asymmetry in the electroproduction of a pseudoscalar meson or a scalar meson off the scalar target

Chueng-Ryong Ji

18/09/2019, 11:55

Hadronic structure

We discuss the electroproduction of a pseudoscalar (0−+) meson or a scalar (0++) meson off the scalar target. The most general formulation of the differential cross section for the 0−+ or 0++ meson process involves only one or two hadronic form factors, respectively, on a scalar target. The Rosenbluth-type separation of the differential cross section provides the explicit relation between the...

87. Double parton distributions of the pion in the NJL model

Wojciech Broniowski (IFJ PAN)

18/09/2019, 12:20

Phenomenological models

We evaluate the quark double parton distribution (dPDF) function of the pion in the Nambu-Jona-Lasinio model, previously used to successfully obtain related quantities such as PDF, PDA, GPD, TMD, etc. In this model the pion appears as a Goldstone boson of the spontaneously broken chiral symmetry and as a fully relativistic q qbar bound state of the Bethe-Salpeter equation. We show that at the...

28. Light front quantum mechanics and quantum field theory

Wayne Polyzou (University of Iowa)

19/09/2019, 09:00

Field theories in the front form

I will give a short introduction to light-front formulations of
relativistic quantum mechanics and quantum field theory. I will
discuss some of the special properties and advantages of a light-front
dynamics. I will also discuss both the relation to and differences
with ``instant-form'' relativistic quantum mechanics and canonical
formulations of quantum field theory.

103. Matching between equal-time and light-front quantization in non-perturbative calculations

Matthew Thomas Walters (CERN)

19/09/2019, 09:30

Field theories in the front form

25. An overview of light-front holography

Ruben Sandapen (Acadia University)

19/09/2019, 10:00

Phenomenological models

Light-front holography refers to an exact correspondance between semiclassical (with zero quark masses and no quantum loops) light-front QCD and a gravitational theory in 5-dimensional anti-de Sitter spacetime. Conformal symmetry is broken in a novel way, namely by the so-called dAFF (de Alfaro, Furbini and Furlan) mechanism which allows the emergence of a fundamental AdS/QCD mass scale...

84. On the light-front wavefunctions and related observables of quarkonium states

Maris Pieter (Dept. of Physics and Astronomy, Iowa State University)

19/09/2019, 11:00

Phenomenological models

The light-front wavefunctions of hadrons allows us to calculate a wide range of physical observables; however, the wave-functions themselves cannot be measured. Furthermore, the light-front wavefunctions are typically expanded in their Fock components, and it is not clear, a priori, how many terms in this expansion are needed for quantitatively reliable calculations of hadron observables, and...

13. Exotic and Conventional Quarkonium Physics Prospects at Belle II

Umberto Tamponi (INFN Torino (IT))

19/09/2019, 11:30

Quarkonia

The Belle II experiment at the SuperKEKB energy-asymmetric $e^{+}{e}^{-}$ collider is a substantial upgrade of the B factory facility at the Japanese KEK laboratory. The design luminosity of the machine is $8\times {10}^{35}$ cm${}^{-2}$s${}^{-1}$ and the Belle II experiment aims to record 50 ab${}^{-1}$ of data, a factor of 50 more than its predecessor. From February to July 2018, the machine has...

38. Hadronic Properties from Basis Light Front Quantization

James Vary (Iowa State University)

19/09/2019, 11:55

Field theories in the front form

Basis Light Front Quantization provides a practical framework and is actively used for solving the mass eigenvalue problem of the light-front Hamiltonian for hadronic systems. I will review recent results for mixed-flavor and light mesons as well as for baryons. These results include masses, decay constants, transition rates, form factors, parton distribution functions including their QCD...

46. Color Confinement and Supersymmetric Properties of Hadron Physics from Light-Front Holography

Stanley Brodsky (SLAC National Accelerator Laboratory)

19/09/2019, 12:20

Phenomenological models

QCD is not supersymmetrical in the traditional sense -- the QCD Lagrangian is based on quark and gluonic fields -- not squarks or gluinos. However, its hadronic eigensolutions conform to a representation of superconformal algebra, reflecting the underlying conformal symmetry of chiral QCD and its Pauli matrix representation. The eigensolutions of superconformal algebra provide a unified Regge...

81. Hadron spectrum and Dyson-Schwinger equations

Gernot Eichmann (Tecnico Lisboa)

20/09/2019, 09:00

Few- and many-body physics

I will review progress in calculating the properties of mesons, baryons and tetraquarks using Dyson-Schwinger and Bethe-Salpeter equations. This includes the spectrum of light and strange baryons and their transition form factors as well as states dominated by four-quark dynamics such as the X(3872) and other heavy-light tetraquark candidates. I will discuss recent advances in determining...

97. PDFs on the Lattice

Fernanda Steffens

20/09/2019, 09:30

Hadronic structure

90. The present and future science program at Jefferson Lab

Jian-Wei Qiu (Jefferson Lab)

20/09/2019, 10:00

Present and future facilities

The CEBAF facility at Jefferson Lab (JLab) recently completed its 12 GeV upgrade, and is now capable of delivering high intensity electron beams to all four experimental halls simultaneously. It is now in its first full year operation and will produce incredibly amount of precision data to help address some critically important 21st century science questions, e.g., what is the role of gluonic...

30. Spin Physics at Hadron Facilities

Oleg Eyser (Brookhaven National Laboratory)

20/09/2019, 11:00

Present and future facilities

The partonic structure of the proton has been established in deep inelastic scattering and a detailed picture of the nucleon has emerged from a wide range of experiments and global analyses. Hadronic collisions allow direct access to the gluon content in the nucleon and polarized beams introduce an additional degree of freedom, spin, which is naturally connected to parton kinematics. Polarized...

63. Singularities in Twist-3 Quark Distributions

Fatma Aslan (NMSU)

20/09/2019, 11:30

Hadronic structure

We find in one-loop calculations and spectator models that twist-3 GPDs exhibit discontinuities. In the forward limit, these discontinuities grow into Dirac delta functions which are essential to satisfy the sum rules involving twist-3 PDFs. We calculate twist-3 quasi-PDFs as a function of longitudinal momentum, and identify the Dirac delta function terms with momentum components in the...

52. Frame dependence of transition form factors in light-front dynamics

Meijian Li (Iowa State University)

20/09/2019, 11:55

Field theories in the front form

We calculate the transition form factor between vector and pseudoscalar quarkonia in both the timelike and the spacelike region using light-front dynamics. We investigate the frame dependence of the form factors for heavy quarkonia with light-front wave functions calculated from the valence Fock sector. This dependence could serve as a measure for the Lorentz symmetry violation arising from...

93. Parton distributions from light-front holographic QCD

Tianbo Liu (Jefferson Lab)

20/09/2019, 12:20

Phenomenological models

Determining quark spin dependent distributions in the proton is a key task in hadron physics to understand strong interactions. Existing world data show positive polarization for up quarks and negative polarization for down quarks. However, perturbative QCD predicts maximally positive polarization for both up and down quarks at large longitudinal momentum limit, $x\to 1$, while extrapolations...