### Conveners

#### Hadron Spectroscopy and Interactions: Session 4-1 C

- Chuan Liu (Peking University)

#### Hadron Spectroscopy and Interactions: Session 4-2 B

- Liuming Liu (Chinese Academy of Sciences)

#### Hadron Spectroscopy and Interactions: Session 6-2 B

- Derek Leinweber (University of Adelaide)

#### Hadron Spectroscopy and Interactions: Session 7-1 C

- Marc Wagner (Goethe University Frankfurt )

I summarize recent work (arXiv:2003.10974) providing a generalization of finite-volume scattering formalism for non-identical pions in isosymmetric QCD. The result allows one to use discrete finite-volume energies, determined using lattice QCD, to constrain scattering amplitudes for all possible values of two- and three-pion isospin. As an example, I present a toy implementation for I(πππ) =...

We present a simplified derivation of the relativistic three-particle quantization condition for identical, spinless particles. The simplification is afforded by using time-ordered perturbation theory (TOPT) and a three-particle quasilocal K matrix that is not fully symmetrized to organize the relevant diagrams in an intuitive manner, ultimately leading to a new form of the quantization...

We show that a recently derived alternative form of the relativistic three-particle quantization condition for identical particles can be rewritten in terms of the R matrix introduced to give a unitary representation of the infinite-volume three-particle scattering amplitude. Combined with earlier work, this shows the equivalence of the relativistic effective field theory approach of Refs. [1,...

Hamiltonian effective field theory (HEFT) is an approach which allows for the extraction of hadron finite-volume energy spectra from scattering observables such as phase shifts and inelasticities. As an alternative to Luscher's method, HEFT easily generalises to systems with multiple coupled channels and multiple bare states. HEFT also allows for the extraction of eigenvectors from the...

In this talk, we show the recent status of the rho resonance study in the HAL QCD method.

We investigate the I=1 two-pion potential at $m_{\pi} \approx 411$ MeV by using a new calculation strategy, namely the combination of three techniques: the one-end trick, the sequential propagator, and covariant approximation averaging (CAA).

Thanks to the new strategy, we determine the non-local I=1...

The origin of the low-lying nature of the Roper resonance has been the subject of significant interest for many years, including several investigations using lattice QCD. It has been claimed that chiral symmetry plays an important role in our understanding of this resonance. We present results from our systematic examination of the potential role of chiral symmetry in the low-lying nucleon...

We study I = 0 quarkonium resonances decaying into pairs of heavy-light mesons using static-static-light-light potentials from lattice QCD. To this end, we solve a coupled channel Schrödinger equation with one confined quarkonium channel and two channels with a heavy-light meson pair to compute phase shifts and t-matrix poles for the lightest decay channel. Finally, we discuss our results in...

We investigate meson-baryon interactions in the HAL QCD method with all-to-all propagators using the stochastic estimations. We mainly report the analysis of the S-wave kaon-nucleon interactions at $m_{\pi} \approx 570$ MeV. Since there are no quark-antiquark creation/annihilation processes in this system, all-to-all propagators merely play a role in increasing statistics. In addition, we...

We explore the quark composition of bottomonium bound states and resonances with I = 0 and L = 0 using lattice QCD static potentials from a previous study of string breaking and the Born-Oppenheimer approximation. We also compare the relative importance of meson-meson and diquark-antidiquark creation operators for the lattice QCD static potential relevant for b-bar b-bar u d tetraquarks with I = 0.

We report our estimation for the Isgur-Wise form factors for the inclusive semileptonic $B \to X_c \ell\nu$ on 2+1-flavor lattice QCD.

The M\"obius domain-wall fermion action is used for light, strange, charm and bottom quarks. The structure function receives contributions from various exclusive modes, including the dominant S-wave states $D^{(*)}_s$ as well as the P-wave states $D_s^{**}$....

The magnetic polarisability is a fundamental property of hadrons, which provides insight into their structure in the low-energy regime. The pion magnetic polarisability is calculated using lattice QCD in the presence of background magnetic fields. The results presented are facilitated by the introduction of a new magnetic-field dependent quark-propagator eigenmode projector and the use of the...

Signal-to-noise problem and excited states contamination, inter alia, make studies of the QCD string breaking phenomenon a challenging task in lattice QCD. The static quark potentials produced for these studies can be combined with the Born Oppenheimer approximation to give an important insight into I=0 quarkonium resonances. Precise determination of various lattice potentials are also needed...

The low-lying spectrum of charmed baryons is calculated in lattice QCD on the $32^3 \times 64$, $N_f = 2 + 1$ PACS-CS gauge configurations at the almost physical pion mass of 156 $MeV/c^2$. By employing a set of interpolating operators with different Dirac structures and quark-field smearings for the variational analysis, we extract the ground and first few excited states of the spin-1/2 and...

The properties of low-lying charmonium mesons offer points of high precision comparison between lattice QCD and experiment, if discretisation effects set by the charm quark mass can be controlled. Using $n_f=2+1+1$ configurations with the HISQ action, developed by the HPQCD collaboration to have very small discretisation errors, we achieve precision at or below the 1% level for a range of...

Mixing in the $\Sigma^0$--$\Lambda^0$ system is a direct consequence of broken isospin symmetry and is a measure of both isospin-symmetry breaking as well as general SU(3)-flavour symmetry breaking. In this talk we present a novel scheme for calculating the extent of the physical $\Sigma^0$--$\Lambda^0$ mixing using simulations in lattice QCD+QED and discuss some of its features and initial results.

We investigate the two-flavour Schwinger model in the canonical formulation with fixed fermion number.

We use Wilson fermions on the lattice and present a formalism which describes the Dirac operator with dimensionally reduced canonical operators.

These reduced operators allow the direct examination of different meson sectors and the determination of the energy spectrum in

each of the...

We search for possibly existent bound states in the heavy-light tetraquark channels with quark content $ \bar{b}\bar{b}ud $, $ \bar{b}\bar{b}us $ and $ \bar{b}\bar{c}ud $ using lattice NRQCD for the heavy quarks. We use different gauge link ensembles with $ N_f=2+1 $ flavours of domain-wall fermions and consider a basis of local and non-local interpolators. Besides extracting the energy...

We compute hybrid static potentials in SU(2) lattice gauge theory using a multilevel algorithm and three different small lattice spacings. The resulting static potentials, which are valid for quark-antiquark separations as small as 0.05 fm, are important e.g. when computing masses of heavy hybrid mesons in the Born-Oppenheimer approximation. We also discuss and exclude possible systematic...

Recent studies by HAL QCD collaboration have been successful in calculating hadron interactions from the first principles of QCD. In this talk, we apply the Laplacian Heaviside (LapH) smearing for the two nucleon source operator to enhance overlap with the low-energy elastic states and calculate the s-wave nuclear force. Our potential with the LapH smeared source has similar structure and...

The glueballs in the SU(N) Yang-Mills theory are theoretically the most natural among composite dark matter scenarios.

In this work, we evaluate the interglueball potential in SU(N) lattice gauge theories using the HALQCD method and derive the glueball dark matter scattering cross section, and then constrain the scale parameter of the gauge theory from the observational data.

We explore the existence of tetraquark resonances with lattice QCD potentials computed for a static b̄b̄ pair in the presence of two light quarks ud. We use the Born-Oppenheimer approximation and an extension of the emergent wave method, where effects of the heavy quark spins are included via the mass difference of the B and the B* meson. Focus is given on a resonance with isospin I = 0 and...