Conveners
Parallel 3: Hadronic structure - Energy-momentum tensor
- Barbara Pasquini (University of Pavia and INFN-Pavia)
Parallel 3: Few- and many-body physics - Bethe-Salpeter equation
- Tobias Frederico (Instituto Tecnologico de Aeronautica)
Parallel 3: Few- and many-body physics - Deuteron
- Gerald Miller (University of Washington, Seattle)
Parallel 3: Exotic objects
- Umberto Tamponi (INFN Torino (IT))
Parallel 3: News from CERN
- Jean-François Mathiot
Parallel 3: Hadronic structure - Orbital angular momentum
- Cédric Lorcé (Ecole polytechnique)
We study the structure of the energy-momentum tensor (EMT) for massive hadrons of spin $\ge $ 1. When considering higher values for the spin of the particle, the number of form factors involved in the decomposition of the EMT local matrix element increases. The Lorentz generators, distinctive of each spin representation, can be used to arrange the structures appearing in the EMT...
In this talk I will discuss the constraints imposed by Poincaré symmetry on the form factors appearing in the Lorentz decomposition of the energy-momentum tensor matrix elements. By adopting a distributional approach, one can prove non-perturbatively that the zero momentum-transfer limits of the leading two form factors are completely independent of the properties of the states in the matrix...
The pion structure in Minkowski space is described in terms of an analytic model of the Bethe–Salpeter amplitude combined with Euclidean Lattice QCD results [1,2]. The model is physically motivated to take into account the running quark mass, which is fitted to Lattice QCD data [3]. In the present work, we extend the previus work donne in [2], with the present model utilized to calculated...
A first, but thorough investigation of a fermion-scalar bound system has been carried out by solving the Bethe-Salpeter equation in Minkowski space and using a ladder kernel containing a massive exchange of a scalar or a vector boson. The LF momentum distributions have been obtained, shedding light on the possibility to correlate the features of those quantities and the underlying dynamics.
Generally speaking, improving our understanding of the interaction in terms of the fundamental degrees of freedom is very important for nuclear and particle non-perturbative physics. As it is very involved problem, simple models are of great value for understanding the basic qualitative features of the solution for more realistic kernels. Unraveling the properties of relativistic three-body...
In the Wick-Cutkosky model [1,2] (two scalar particles interacting by massless exchange), for enough large coupling constant ($\alpha>\frac{\pi}{4}$), there exist two different types of solutions of the Bethe-Salpeter equation [3]. Some solutions turn, in the non-relativistic limit, into the well-known Coulombien ones; other solutions, on the contrary, disappear in the non-relativistic limit...
We study electro-disintegration of the deuteron at high momentum transfer aimed at describing its short-distance structure. Such studies are relevant for a number of phenomena related to high density nuclear matter, relativistic NN-interaction and at short distances nuclei structure in general. Due to the relativistic nature of the process, the theoretical framework is based on light-front...
Energy dependence of the vector Ay and tensor Ayy and Axx analyzing powers in deuteron-proton (dp) elastic scattering is investigated in the energy range from 400 MeV - 2000 MeV at large scattering angles. The detection of the dp elastic scattering events has been done by the coincident measurement of deuteron and proton in the the angular range of 60-135 deg. in the cm. The Ay, Ayy and Axx...
The question of the existence of compact tetraquarks is studied in the large-$N_c$ limit of QCD. Considering the fully exotic case, corresponding to four different quark flavors, it is shown that consistency conditions of correlation functions of color-singlet bilinear currents require the existence of two different tetraquarks, each decaying preferentially into a single two-meson channel. On...
Intrinsic heavy quarks contributions to the nonperturbative structure of hadrons is a rigorous property of light-front wavefunctions in QCD.
The intrinsic distributions scale as $1/ m^2_Q$ and are maximal at minimal off-shellness; i.e., equal rapidity and thus
$x_Q \propto \sqrt{m^2_Q + k^2_{\perp Q}}$.
An empirical constraint on the intrinsic charm (IC) probability in the proton is...
Hadron-lepton and hadron-hadron interactions at large momentum transfer are studied in the presence of Lorentz-violating background fields affecting quarks. Connections are made with the operator-product expansion and leading-twist parton distribution functions are derived. Cross sections for deep inelastic scattering and the Drell-Yan process are calculated at leading order for minimal and...
The study of photonuclear and two-photon interactions in ultra-peripheral collisions (UPC) is a tool to learn about the initial state of nuclei. In such collisions, the nuclei do not overlap and strong nuclear interactions are suppressed.
New ALICE results from LHC Run 2 are presented for forward J/ψ photoproduction, which is sensitive to the nuclear gluon distribution. The large data...
The planned new fixed-target COMPASS++/AMBER QCD facility takes advantage of the uniqueness of the muon and hadron beams available at CERN. Its broad experimental programme aims at a deeper understanding of the strong interaction. After summarizing the main features of the facility, the present talk will focus on the Drell-Yan and charmonium production part of the programme. New...
While twist-2 GPDs allow for a determination of the distribution of partons on the transverse plane, twist-3 GPDs contain quark-gluon correlations that provide information about the average transverse color Lorentz force acting on quarks. We demonstrate how twist-3 GPDs can be used to provide transverse position information about that force.
The parton structure of the proton can be studied mainly using two types of hard scattering processes: exclusive processes, giving access to Generalised Parton Distributions (GPDs), and semi-inclusive processes, described in terms of Transverse Momentum Dependent parton distributions (TMDs). In full QCD no relations exist between GPDs and TMDs. However, a connection between T-odd effects...
The most common decompositions of angular momentum are the Jaffe-Manohar (canonical) and Ji (kinetic) decompositions, which differ by the potential angular momentum and depend on how the contributions are attributed to quarks and gluons. Lattice calculations has shown that difference between such decompositions is non-zero.
We justify using perturbation theory within a simple scalar diquark...
The transverse spatial distribution of orbital angular momentum (OAM) in the nucleon is studied at peripheral distances b∼1/Mπ. We use Chiral EFT to compute the form factors of the energy-momentum tensor and their peripheral transverse densities, including the density associated with light-front OAM. This density is represented in first–quantized form, as an overlap integral of chiral...
