Conveners
Light Quarks: B1a (Parallel B)
- Tetsuo Hatsuda (RIKEN iTHEMS)
Light Quarks: B1b (Parallel B)
- Bernhard Ketzer (University of Bonn (DE))
Light Quarks: B2a (Parallel B)
- Andreas Kronfeld (Fermi National Accelerator Lab. (US))
Light Quarks: B2b (Parallel B)
- James Zanotti (The University of Adelaide)
Light Quarks: B3aI (Parallel B)
- Adam Szczepaniak (Indiana University)
Light Quarks: B3bI (Parallel B)
- Zhan-Wei Liu (Lanzhou University)
Light Quarks: B4aII (Parallel B)
- Gernot Eichmann
Light Quarks: B4a1 (Parallel B)
- Peter Hurck (University of Glasgow (GB))
Light Quarks: B4b (Parallel B)
- Chengping Shen (Fudan University (CN))
Light Quarks: B4cI (Parallel B)
- Mark Wise
Light Quarks: B4cII (Parallel B)
- Kim Maltman
The spectrum of hadronic states holds valuable information about the interaction of the strong force. Photoproduction experiments can provide crucial insights due to their ability to produce a wide range of conventional and non-conventional hadrons, such as exotic hybrid mesons with gluonic degrees of freedom.
The GlueX experiment at Jefferson Lab, VA, USA, features a 9 GeV linearly polarized...
We present a new method of using lattice QCD to extract the intrinsic soft function and the Collins-Soper kernel for TMDPDFs. This method relies on the computation of Wilson loops involving Wilson lines with complex directional vectors. In this talk, progress in numerical implementation of this approach will also be discussed.
We review recent developments in the determination of the quark and gluon structure of hadrons from global QCD analysis within the JAM analysis framework, including polarized and unpolarized PDFs in the proton, and momentum distributions in the pion.
The nontrivial quark structure of light scalar mesons f0(500), f0(980) and a0(980) remains controversial for many years. In passed years, BESIII has collected 8.0 and 7.33 fb^-1 of e+e- collision data samples at 3.773 and 4.178-4.226 GeV, respectively. In this talk, we will review all the studies about light scalar mesons via semileptonic D decays at BESIII. These studies includes the decays...
The origin of the EMC effect is one of the major unsolved problems in nuclear physics. Recent studies suggest that the EMC and Short Range Correlation (SRC) are correlated, and quantitative relations are obtained. In this talk, I will introduce our recent work on the EMC effect for the gluon and its correlation with the SRC. We explore the gluon EMC effect through heavy flavor production in...
The NA62 experiment at CERN collected the world's largest dataset of charged kaon decays in 2016-2018, leading to the first measurement of the branching ratio of the ultra-rare $K^+ \rightarrow \pi^+ \nu \bar\nu$ decay, based on 20 candidates.
In this talk NA62 reports new results from the analyses of rare kaon and pion decays, using data samples collected in 2017-2018. A sample of $K^+...
The formalism of colour-Lorentz forces offers a novel approach to understanding the mechanisms that bind quarks into hadrons. We present a lattice QCD calculation of the transverse spatial distribution of the colour-Lorentz force acting on a struck quark in a proton. Utilising $N_fโ=2+1$ flavors of dynamical fermions at the SU(3) symmetric point across three lattice spacings, we identify a...
COMPASS is the longest-running experiment at CERN, with a record-breaking 20 years of data collection from 2002 to 2022. The experiment has a unique and diverse physics program focused on nucleon structure and spectroscopy measurements.
The experimental results obtained by COMPASS during Phase I (2002-2011) and Phase II (2012-2022) for a wide range of nucleon spin structure-related DIS and...
Owing to the color confinement, the phenomena of strong interaction physics can be described either in terms of fundamental quarks and gluons of Quantum Chromodynamics (QCD) or as mesons and baryons and the nuclear force between them. Mesons and baryons themselves are confined dynamic systems of quarks and gluons. Understanding fully the relationship between this dual representation of...
The gravitational form factors (GFFs) describe the fundamental structure of nucleons and nuclei through the matrix element of the energy-momentum tensor. Their Fourier transform allows a description of the spatial distribution of mass, angular momentum, pressure, and shear force densities for both quarks and gluons in the nucleon. In this presentation, I will focus on the recent results of the...
We describe recent developments in the determination of the strong coupling $\alpha_s$ from finite energy sum rule (FESR) analyses of non-strange spectral distributions measured in hadronic $\tau$ decay. This includes details of an isovector, vector channel analysis employing a improved version of the relevant spectral function obtained via use of a recent BaBar determination of the...
Recent lattice QCD results for the low-lying positive parity $\Delta$ spectrum indicate that the $2s$ excitation of the ground state $\Delta(1232)$ lies at ~2.15 GeV. This sits significantly above the experimentally measured mass of the first positive parity excitation, the $\Delta(1600)$. Using Hamiltonian Effective Field Theory (HEFT), the $1s$ and $2s$ states are represented by...
For over seventy years, the internal structure of the proton has been studied using electromagnetic interactions to measure elastic form factors. The quark structure has been explored for over fifty-five years, and the helicity structure for over forty years. However, our understanding of the protonโs mechanical propertiesโsuch as internal mass distribution, angular momentum, pressure, and...
In this talk, I will present our recent work on two-loop QCD corrections to pion electromagnetic form factors with large momentum transfer.
We explicitly verify the validity of the collinear factorization to two-loop order for this observable, and obtain the respective IR-finite two-loop hard-scattering kernel in the closed form.
Incorporating this new ingredient of correction, we make a...
I will discuss a lattice QCD calculation of the nucleon electric polarizabilities at the physical pion mass. Our findings reveal the substantial contributions of the Nฯ states to these polarizabilities. Without considering these contributions, the lattice results fall significantly below the experimental values, consistent with previous lattice studies. This observation has motivated us to...
Pseudoscalar mesons are the simplest quark-antiquark bound states. Understanding their internal structure is at least as important in comprehending the working of quantum chromodynamics as hydrogen atom was for understanding quantum electrodynamics. The Q^2 evolution of their electromagnetic and two-photon transition form factors from Q^2 -> 0 to its asymptotically large values helps us...
Baryon spectroscopy gives insights into the dynamics between the constituents of baryons and study quantum chromodynamics (QCD) in the non-perturbative regime. Quark models and Lattice calculations predict a large number of baryons, but only a fraction of them have been found experimentally.
The baryon spectra can be probed with a real photon beam by studying various different...
While the excitation spectrum of light mesons, which are composed of up and down quarks, is already mapped out fairly well, the spectrum of strange mesons is still to be mapped out in detail, potentially holding many surprise.
At the COMPASS experiment at CERN, we study the strange-meson spectrum in the diffractive scattering of a high-energy kaon beam.
In this talk we will focus on the...
Computing the parton distribution functions (PDFs) of hadrons from lattice QCD poses well known challenges due to the theory being formulated on discrete Euclidean spacetime. For example, power divergent mixing due to the reduced symmetry of the lattice theory precludes obtaining Mellin moments of PDFs starting at <x^4> or higher, and requires the use of boosted states with poor...
Using the worldโs largest samples of J/psi and psi(3686) events produced in e+e- annihilation, BESIII is uniquely positioned to study light hadrons in radiative and hadronic charmonium decays. In particular, exotic hadron candidates including multiquark states, hybrid mesons and glueballs can be studied in high detail. Recent highlights on the light exotics searches, including observation of...
A unified set of predictions for pion and kaon elastic electromagnetic and gravitational form factors is obtained using a symmetry-preserving truncation of each relevant quantum field equation. A key part of the study is a description of salient aspects of the dressed graviton + quark vertices. The calculations reveal that each mesonโs mass radius is smaller than its charge radius, matching...
We present a talk on recent investigations of the gravitational form factors (GFFs) and relevant mechanical structure of the nucleon, focusing also on the flavor components of the GFFs. We employ a pion mean-field approach, grounded in the large Nc limit of Quantum Chromodynamics (QCD). We mainly consider the contributions from the twist-2 operators to the flavor-triplet and octet GFFs. We...
In this work, we study the generalized transverse momentum dependent distribution (GTMD) $E_{21}^{\nu}(x, p_{\perp},\Delta_{\perp},\theta)$ for proton using light-front quark-diquark (LFQDM) model. We construct the $E_{21}^{\nu}(x, p_{\perp},\Delta_{\perp},\theta)$ GTMD using the GTMD overlap equation in light-front wave functions obtained from the GTMD correlator with Dirac matrix structure...
The electromagnetic structure of hadrons can be determined by evaluating the scattering of light off the system, provided by the Compton amplitude. Such an evaluation is infeasible mathematically at low energies due to the non-perturbative nature of QCD. Lattice QCD provides a way to numerically determine these structures using a path-integral approach. To produce results in a feasible amount...
The high-precision study of multi-nucleon matrix elements via lattice QCD requires numerical resources that increase dramatically with the number of nucleons, due to signal-to-noise degradation and a factorial number of Wick contraction terms. To address this, we present a particular variant of e-graphs (equality graphs) called tensor e-graphs which construct composite tensors that are...
Chiral trajectories of dynamically generated resonances are connected to the SU(3) breaking pattern and their nature. From an analysis of a recent LQCD simulation on the $\pi\Sigma-\bar{K}N$ scattering for $I=0$, and the study of the quark mass dependence of the octet baryons, we determine for the first time the trajectory of the two poles associated to the $\Lambda(1405)$ towards the...
We investigate the roles of the electromagnetic interaction in the photoproductions and radiative decays of nucleon excitations and exotic heavy hadrons, as well as their relevant electromagnetic form factors. Our quantitative investigation shows that their electromagnetic properties can provide important hints to decode the inner structure of hadrons. The electromagnetic processes can better...
At BESIII, the electromagnetic form factors (EMFFs) and the pair production cross sections of various baryons have been studied. The proton EMFF ratio |GE/GM| is determined precisely and line-shape of |GE| is obtained for the first time. The recent results of neutron EMFFs at BESIII show great improvement comparing with previous experiments. Cross sections of various baryon pairs (Lambda,...
The color/quark deconfinement is one of the remarkable features of QCD phase transitions, with the observation of (strongly coupled) quark-gluon plasma in the heavy-ion collision experiments. In phenomenology, the deconfinement phase transition corresponds to the Polyakov loop which symbols the glue dynamics.
In this talk, I will discuss the relevance of the Polyakov loop for the QCD...
The rare radiative $K^+\to\pi^+\ell^+\ell^-$ decays ($\ell=e,\mu$) provide experimental access to the $K^+\to\pi^+\gamma^*$ transition. The relevant form factor is conventionally written in terms of two hadronic parameters, $a_+$ and $b_+$, which are being measured by NA62 in both electron and muon channels. Comparing the two channels allows for a stringent test of lepton-flavor universality....
I will report the three-dimensional structure of the proton obtained from a recently constructed nonperturbative approach based on the light-front Hamiltonian formalism, named Basis Light-front Quantization (BLFQ). First, we obtain the light-front wave function of the proton through solving the eigenvalue problem of the light-front Hamiltonian of QCD in $|qqq\rangle$+$|qqqg\rangle$+$|qqqq\bar...
We study the $J/\psi \to \phi \pi^+ a_0(980)^- (a_0^- \to \pi^- \eta)$ decay, evaluating the double mass distribution in terms of the $\pi^- \eta$ and $\pi^+ a^-_0$ invariant masses. We show that the $\pi^- \eta$ mass distribution exhibits the typical cusp structure of the $a_0(980)$ seen in recent high statistics experiments, and the $\pi^+ a^-_0$ spectrum shows clearly a peak around $M_{\rm...
A precision determination of the pion-nucleon sigma term requires the consideration of isospin-breaking corrections, given that such effects are enhanced due to the chiral suppression of the isoscalar pion-nucleon amplitude. In particular, when comparing phenomenological and lattice-QCD determinations, it is critical that consistent definitions be employed. In the talk, I will give an update...
Recently, two experiments in Hall C at Jefferson Lab finished data taking. One experiment focused on a precision measurement of the virtual photon asymmetry A$_1^n$ at large values of Bjorken-x (0.61 < x < 0.77) at various values of Q$^2$, and the other experiment measured the spin structure function g$_2^n$ over a large range of Bjorken-x (0.20 < x < 0.95) to extract the Q$^2$ evolutions of...
I will review the status of theoretical development and analysis results related to searches for the $\pi_1$ exotic hybrid meson.
The recent PRad experiment at Jefferson Lab has precisely measured the cross sections for elastic electron proton scattering at four momentum transfer square ($Q^2$) from $2\times10^{-4}$ to $6\times10^{-2}$ GeV$^2$/c$^2$. The charge radius of proton was extracted based on the measured proton form factors at very low $Q^2$. This experiment utilized a high precision, hybrid calorimeter (HyCal)...
The dominant contribution to the theoretical uncertainty in the extracted weak parameters of the Standard Model comes from the hadronic uncertainties in the electroweak box diagrams, i.e. $\gamma-W^\pm/Z$ exchange diagrams. A dispersive analysis relates the box diagrams to the parity-odd structure function, $F_3$, for which the experimental data either do not exist or belong to a separate...
The parton structure of the nucleon and pion is investigated in a model that allows one to see if the dressing of quarks can, by itself, produce realistic gluon contributions to momentum fractions, spin, mass distributions and mass radii. The model is the Dyson-Schwinger Equations in Rainbow-Ladder truncation and involves calculation of the second Mellin moment of certain GPDs. For the...
In the present work, we use the final state interaction formalism to investigate the production of the $f_0(1710) $ and $a_0(1710) $ states in the Ds decay processes. In the quark level, we consider the W-internal and -external emission mechanisms. In the hadron level, we take the final state interaction into account based on the coupled channel approach, where the $f_0(1710) $ and $a_0(1710)...
Based on the vector meson dominance model, we conducted a theoretical study on the timelike electromagnetic form factors of hyperons. We found that the timelike electromagnetic form factors of hyperons also exhibit significant oscillatory behavior, but further theoretical and experimental research is needed. Additionally, this talk will provide discussions on the reasons for the oscillatory behavior.
We present the polarization measurement of the $\Xi^-$ baryon produced in the $^{12}C(K^-,K^+)\Xi^-$ reaction and in the $p(K^-,K^+)\Xi^-$ reaction at the center-of-mass energy $\sqrt s=2.15$ GeV/c$^2$. We have collected 300k $^{12}C(K^-,K^+)\Xi^-$ events and reconstructed 30k $\Xi^-$ with a 1.8 GeV/c $K^-$ beam in J-PARC E42.
The polarization analysis of the $^{12}C$ dataset will provide...
We measured double-strangeness systems produced in the $^{12}C(K^{-},K^{+})X$ reaction which involves a $\Xi^{-}$ hyperon and a $\Lambda\Lambda$ hyperon pair at the J-PARC using 1.8 GeV/$\mathit{c}$ $K^{-}$ beam.ย ย
The E42 experiment which has a primary goal to search for the H-dibaryon collected 300K $^{12}C(K^{-}, K^{+})X$ reaction events containing thousandsย of $\Lambda\Lambda$ย events...
The Fourier transformed chiral even generalized parton distributions $(GPDs)$ for purely transverse momentum transfer $(\Delta^+=0)$ characterize an individual parton distribution of a hyperon in a perpendicular plane at some distance from the center of momentum of the system. Further, the presence of left-right asymmetry in the distorted parton distribution gives a clue for the presence of...
We present a comprehensive investigation of leading-twist lightcone distribution amplitudes (LCDAs) and quasi distribution amplitudes (quasi-DAs) for light octet and decuplet baryons within large momentum effective theory (LaMET). In LaMET, LCDAs can be factorized in terms of a hard kernel and quasi-DAs that are defined as spatial correlators and calculable on Lattice QCD. To renormalize...
Characterizing the internal structure of nucleons in terms of sea quarks and gluons is a challenging task in hadronic physics. Both theoretical and experimental studies have validated the impact of valence and sea on different properties of nucleon. We employed the statistical model to investigate the contribution of strange sea to the charge radii and quadrupole moment of nucleons. Here,...
I will be participating in the round table on "PDF, TMD, GDP, at a crossroad: open problems and perspective, impact on LHC studies and new physics search, impact on EIC and EICC hadron structure studies"
