Conveners
WG2 parallel session
- Mikhail Mikhasenko (Ruhr University Bochum)
WG2 parallel session
- Vadim Baru (Ruhr University Bochum)
WG2 parallel session
- James Ritman (RUB and GSI)
WG2 parallel session
- Alexandre Deur (Jefferson Lab)
WG2 parallel session
- Christian Weiss (Jefferson Lab)
The first excited state of the nucleon dominates many nuclear phenomena at energies above the pion-production threshold and plays a prominent role in the physics of the strong interaction. The study of the N to $\Delta$ transition form factors (TFFs) allows to shed light on key aspects of the nucleonic structure that are essential for the complete understanding of the nucleon dynamics. In this...
In this talk we discuss how the chiral effective Lagrangian is generalized systematically to curved spacetime and how the corresponding energy-momentum tensor (EMT) is obtained. As next, we discuss the nucleon and delta gravitational form factors, which are described by the diagonal hadronic matrix elements of the EMT at low energies. Furthermore, we discuss the transition gravitational form...
We present the results of a partial wave analysis of the global real Compton scattering (RCS) database, extracting the leading scalar and spin polarisabilities of the proton.
Exploring the nucleon using electromagnetic probes reveals a fine and intricate interplay between its various structural properties. As an example, the nucleon polarisabilities encode the two-photon response, such as...
With the existing 10 billion J/psi events accumulated at BESIII, the high production of long-lived baryons in J/psi decays serves as a novel source of hyperon beams, which open a unique opportunity for exploring the hyperon-nucleon interactions. By studying these hyperons with the beam pipe and the inner tube of the MDC detector, the recent results, including interactions of $\Lambda p$,...
The well-established $\Lambda(1405)$ hyperon with $J^\pi = \frac{1}{2}^-$ may be a dual structure consisting of two overlapping $I=0$ resonances. Each resonance may couple to $\Sigma\pi$ and $N\overline{K}$ final states, but a direct measurement of these two decays for each resonance has not previously been done. Using the GlueX detector system at Jefferson Lab we have obtained high...
Whether one is interested in measuring transition matrix elements or extracting scattering parameters, a common requirement is to constrain and determine an analytical expression for the scattering amplitude. A systematically improvable, well developed theoretical method is to determine the finite volume spectrum using lattice QCD and connect it to the infinite volume scattering amplitude...
A coupled-channel approach is applied to the charged tetraquark state $T_{cc}$ discovered by the LHCb Collaboration and the lattice data. Special attention is paid to the three-body and left-hand cut for the physical and unphysical pion mass cases, respectively. We discuss the lattice data to stress a potentially strong impact of left-hand cuts from the one-pion exchange on the pole extraction...
I will discuss scalar and tensor charmonium resonances determined using lattice QCD. Working at $m_\pi\approx 391$ MeV, more than 200 finite-volume energy levels are computed and these are used in extensions of the Lüscher formalism to determine infinite volume scattering amplitudes. Working in the approximation where charm-annihilation is forbidden, the ground state $\chi_{c0}(1P)$ and...
We employ a chiral effective field theory-based approach to connect $DD^*$ scattering observables at the physical and variable pion masses accessible in lattice QCD simulations. We incorporate all relevant scales associated with three-body $DD\pi$ dynamics and the left-hand cut induced by the one-pion exchange for pion masses higher than the physical one, as required by analyticity and...
The scattering lengths on the interactions between the spin-1/2 doubly charmed barons and Nambu-Goldstone bosons are of great importance for the investigation of the spectroscopy of the doubly charmed baryons. On the one hand, the S- and P-wave scattering lengths are predicted in a manifestly relativistic baryon chiral perturbation theory at leading one-loop order. On the other hand, results...
Vector-meson exchange can be naturally introduced for both quark and hadron interactions in the framework of the hidden local symmetry (HLS) for the chiral dynamics. In the studies of Pc hadronic molecules [1,2] and whole spectrum of hadronic ground states [3,4], the vector meson exchanges are found to play more important role to reproduce the data than pseudoscalar meson exchanges, with many...
In this talk I discuss Low-Energy Constants (LEC) in the chiral Lagrangian with three light flavors from current Lattice QCD data. The LEC are adjusted to describe the baryon octet and decuplet masses from a large set of lattice ensembles at N3LO, where finite-box and discretization effects are considered. Faithful results require in particular accurate baryon masses on flavor symmetric...
Our work focused on studying the scattering length of $J/\psi N$ under gluon exchange via dispersion relations and compared the results with contributions from existing coupled-channel processes. Starting from the SU(3) tree-level chiral amplitudes of $N\bar{N}\to\pi\pi/K\bar{K}$, we obtained the $S$-wave amplitude considering the final state interactions of the $\pi\pi$-$K\bar{K}$ coupled...
The baryon-meson scattering amplitude is calculated under the formalism of $1/N_c$ expansion of QCD. The obtained results consider the effects of the decuplet-octet baryon mass difference and perturbative flavor $SU(3)$ symmetry breaking in the complete computation for the first time. Since the resulting expressions can be applied to any baryons and mesons, when the Gell-Mann - Nishijima...
In this talk, our analysis of neutrino-induced single pion production off the nucleon within the framework of manifestly Lorentz-invariant chiral perturbation theory is presented. We consider tree and one-loop diagrams up to and including third chiral order, explicitly incorporating the $\Delta$(1232) resonance. To handle terms breaking the power counting between loop and small momentum...
The nucleon self-energy is calculated in SU(2) covariant chiral perturbation theory (ChPT) to analyze the pion mass dependence of the nucleon mass up to chiral order $\mathcal{O}(q^6)$, i.e., including two-loop diagrams. In a first step, all diagrams are expressed by a small set of (scalar) master integrals. The extended on-mass-shell (EOMS) renormalization scheme is applied, where (next to...
Nonleptonic hyperon transitions are studied in a relativistic framework of chiral perturbation theory ($\chi$PT). Previously, one-loop corrections to parity-violating and -conserving partial-wave amplitudes S and P have been computed in a nonrelativistic approach, focusing on the leading chiral logarithms [1]. This study concluded that a satisfying agreement with data and reasonable...
The GlueX detector in the experimental Hall-D at Jefferson Lab offers a unique opportunity to perform a measurement of the decay width of eta mesons through the Primakoff effect. The experiment complements the physics program at Jefferson Lab on measuring the decay width of light pseudoscalar mesons via the Primakoff process. The goal of the experiment is to measure differential cross sections...
Fragmentation Function (FF) plays a crucial role in describing the hadronization process. We report the measurements of normalized differential cross sections of inclusive pi0, Ks, and eta production as a function of hadron momentum at six energy points with $q^2$ transfer from 5 to 13 GeV${}^2$ at BESIII. The results of pi0 and Ks with a relative hadron energy coverage from 0.1 to 0.9...
By considering the one loop background field method for the quark-antiquark interaction mediated by non perturbative one-gluon exchange, U(3) flavor dependent corrections to the NJL-model coupling constant are derived in the local limit. Meson and quark mixing(s) are discussed, basically emerging due to the different representations in which quarks and quark-antiquark meson are defined. These...
The breaking of conformal and chiral symmetry determine the structure of the QCD vacuum and condition the emergent properties of light hadrons. We review recent efforts in studying these phenomena in the instanton liquid model of the QCD vacuum, a semiclassical picture abstracted from lattice QCD calculations. Chiral symmetry breaking is caused by the fermionic zero modes induced by the...
We examine a pattern of dynamical chiral symmetry breaking making use of the vacuum energy density as a function of the quark condensate. We compute the vacuum energy density and the quark condensate in the interacting instanton liquid model (IILM) with three-flavor quarks. These computations are performed by using a numerical simulation of the canonical IILM, i.e., the number of instantons...
The issue of proper definition of spatial densities through matrix elements of local operators has attracted much attention in the last few years. In this talk, the novel definition of gravitational local spatial densities of hadrons using sharply localised wave packets will be discussed. We will show how the traditional densities in the Breit frame appear and how they differ from densities in...
The transition-density formalism is highly efficient for interactions with perturbative probes in few-nucleon systems. One- and two-body transition densities that encode the nuclear structure of the target are evaluated once per nucleus and stored. They are then convoluted with an interaction kernel to produce observables. The same densities can be used with different kernels. This method...
Pion-Photoproduction and other elastic processes are analyzed in chiral effective field theory around threshold. We extend the work by Lenkewitz et. al. to include the chiral SMS potential with uncertainty estimation based on cutoff variation. In particular we consider as targets ${}^3\mathrm{He},\;{}^4\mathrm{He} $ and ${}^6\mathrm{Li}$ which enter through their probability density amplitudes...
In this talk, we will discuss a recent study on the electromagnetic form factor of nucleons from our group. The SU(3) chiral effective field theory is applied to calculate the potential of nucleon anti-nucleon scatterings up to the next-to-leading order. The potentials are then input into the Lippmann-Schwinger equation, and the scattering amplitudes are solved. These potentials are input as...
The electromagnetic form factors of the nucleon have been widely used for exhibiting how the charge and magnetization distributions are spatially distributed inside a nucleon in the Breit frame. Similarly, the Energy-Momentum-Tensor form factors (i.e. gravitational form factors, GFFs) characterize the mechanical properties, such as the three-dimensional distributions of mass, angular momentum,...
The Bernabéu-Tarrach sum rule, which could potentially provide an additional data-driven constraint on nucleon electric polarizabilities, will be discussed. Moreover, its convergence implies a sum rule for the unknown subtraction function in the two-photon exchange contribution to the Lamb shift. The verification of these sum rules using covariant chiral perturbation theory and the naïve...
