Conveners
Hadron Spectroscopy and Interactions
- Sinya Aoki (Kyoto University)
Hadron Spectroscopy and Interactions
- Chuan Liu (Peking University)
Hadron Spectroscopy and Interactions
- Sinead Ryan (Trinity College Dublin)
Hadron Spectroscopy and Interactions
- Akaki Rusetski
Hadron Spectroscopy and Interactions
- Gunnar Bali (Universität Regensburg)
Hadron Spectroscopy and Interactions
- Sasa Prelovsek
Hadron Spectroscopy and Interactions
- Nilmani Mathur
Belle experiment discovered two tetraquark candidates $Z_b(10610)$ and $Z_b(10650)$ with flavor structure $\bar bb\bar du$ in 2011. We present the lattice study of the $\bar bb\bar du$ system in the approximation of static $b$ quarks. The ground and the excited eigenstates are extracted as a function of separation $r$ between $b$ and $\bar b$. The lower eigenstates at small $r$ are...
Lattice QCD Simulations with Nf=2+1 dynamical quark flavors are quite common and,
due to the decoupling of the charm quark, sufficient for the study of low energy physics with energies far below the charm threshold. However when used in studies of charm physics, the quenching of the heavy quarks may introduce large uncontrolled systematic uncertainties. To assess how big these effects might be...
We present the results of a lattice calculation of four-quark states with quark contents $q_1q_2\bar{Q}\bar{Q}, \, q_1,q_2 \subset u,d,s,c$ and $Q \equiv b,c$ in both spin one ($J=1$) and spin zero ($J=0$) sectors. For the spin one states we find that for both doubly heavy quarks and particularly for the doubly bottom quarks the ground state energy levels are below their respective...
Preliminary results for the spectra of excited and exotic hidden and open bottom mesons are presented. The calculation on dynamical anisotropic ensembles exploits distillation enabling the use of a large basis of interpolating operators including operators proportional to the gluonic field strength which are relevant for hybrid states. A comparison of results with similar calculations in the...
The likelihood that doubly-heavy tetraquarks will be strong-interaction stable is already suggested by features of heavy baryon phenomenology, and confirmed by recent lattice results. Phenomenological input in this case is possible because the light-quark configurations present in a putative tetraquark state are also present in heavy baryons. There are, however, additional light-quark...
Preliminary results are presented for nucleon-pion scattering amplitudes in the $I=3/2$ channel. The calculations are performed on a set of $N_\text{f} = 2+1$ Wilson clover ensembles generated by the CLS initiative with pion masses down to $m_\pi = 200\text{MeV}$ where the $\Delta(1232)$ state is unstable. The required hadron correlation functions are efficiently evaluated using the stochastic...
We present technical details of an analysis of pseudo-scalar data from a
QCD simulation with staggered fermions. The data were obtained close to
the physical point with an inverse lattice spacing of about 3 GeV, and
$N_f=2+1+1$. We compare different methods of extracting effective masses
and decay constants in lattice units. The results of several correlated
and uncorrelated fitting methods...
The Large $N_c$ limit is often invoked in phenomenological approaches. Even though it is a useful simplification of QCD, the systematic uncertainties of these large-$N_c$-inspired approximations to QCD remain unclear. Moreover, it fails in some observables, such as the ratio of isospin amplitudes in the $K \to \pi \pi$ weak decays. In this context, lattice QCD has a lot of yet unexplored...
Parameterizing low-lying scalar resonances remains a challenge. Such is the case for $K^{\star}_{0}(700)$ for which the near threshold experimental results for the corresponding $K\pi$ scattering amplitude are limited. However, production channel data, e.g. $D\to K\pi\pi$, from experiments BES and E791 show clearer evidence of the existence of this resonance. I will present our results for the...
Recent results will be presented of computations of meson-meson scattering processes in several partial waves containing unstable resonances. We will cover $\pi K$ scattering at several pion masses from arXiv:1904.03188, and an extraction of the $b_1$ resonance seen in dynamically-coupled $^3S_1$-$^3D_1$ $\pi\omega$ scattering coupled to $\pi\phi$, from arXiv:1904.04136.
The pion-pion channel is the benchmark for lattice QCD scattering calculations. In the isospin limit, three channels describe $\pi\pi$ scattering completely, having distinct properties in each channel. The attractive $I=0$ and $I=1$ channels are dominated by the broad $\sigma$ and narrow $\rho$ resonances, respectively, while the $I=2$ channel has no low energy resonance. Our group has...
We present updated results on the scattering of pseudoscalar, vector,
and scalar mesons on a physical pion mass, 2+1 flavor mobius-DWF,
ensemble with periodic boundary conditions (PBCs) generated by the RBC
and UKQCD collaborations. Using all-to-all propagators, we produce
thousands of correlator momentum combinations. Energy spectra and phase
shifts, including excited states, are then...
We present first results of the scale setting for QCD with $N_f=3+1$ dynamical quarks on the lattice. We use a recently proposed massive renormalization scheme with a non-perturbatively determined clover coefficient. To relate the bare coupling of the simulations to a lattice spacing in fm, we use decoupling of charm at low energy and the value of a dimensionless quantity...
Hamiltonian effective field theory has been used for explaining Lattice data. We develop it within partial waves mixing in the rest frame. The dimension of the Hamiltonian can be highly reduced with the partial wave cut-off and rotation symmetry. We apply this method to extract the Pion-Pion s-, d- and f-wave phase shifts within Isospin=2 case.
In the two body system, the S matrix in the infinite volume is defined in the rest system, while to obtain more spectra in finite volume, people extract the energy spectrum of finite volume in the moving system. As a result, it needs momentum transformation to connect the energy spectrum in the moving finite volume and the S matrix in the infinite volume. In this work, we find a general...
We present results of our study of the rho resonance properties based on
N_f=2+1+1 gauge configurations produced by the ETMC. We investigate the p-wave
phase shift for a range of pion mass values from about 200 to about 400 MeV and
for three values of the lattice spacing. We perform an extrapolation to the
chiral and continuum limit and extract resonance mass and width at the physical
point.
We report recent theoretical and practical progresses in the HAL QCD potential method, which are summarizewd as follows.
(1) The explicit definition of the potential in terms of the derivative expansion.
(2) The construction of Hermite potentials from non-Hermite potentials.
(3) HAL QCD potentials from NBA wave fucntions in the moving systems.
(4) The partial wave decompositions on the finite...
We observe that the ratio of the on-shell scattering amplitude to
the Bethe-Salpeter (BS) wave function outside the interaction range
is almost independent of time in our quenched calculation of the I=2
two-pion scattering with almost zero momentum. In order to discuss
the time independence, we present a relation between the two-pion
scattering amplitude and the surface term of the BS...
In this talk, we show recent developments in the HAL QCD method including quark annihilation processes. We apply the hybrid method for all-to-all propagators, which combines a low-mode spectral decomposition of the quark propagator and noisy estimators for remaining high modes, to the HAL QCD potential for the first time. Using this combination, we investigate the $I=1,2$ $\pi \pi$...
First-principles determination of baryon interactions plays a crucial role to build a bridge between particle, nuclear and astro-physics. In this talk, we will give an overview for our recent calculations at m_pi = 0.27 GeV, where the interactions are extracted from Nambu-Bethe-Salpeter (NBS) correlators by the time-dependent HAL QCD method. We also discuss quark mass dependence of baryon...
We will present the first ever determination of the nucleon spectrum using HISQ valence quarks in combination with the (2+1+1) MILC-HISQ sea quarks ensembles at the physical point. We performed analyses with both Bayesian and GEVP methods to demonstrate control over excited states, and three lattice spacings, $\sim$0.15fm, $\sim$0.12fm, and $\sim$0.09fm, were used to extrapolate to continuum....
We present continuum limit results of the quark mass dependence of octet and decuplet baryon masses. These are obtained on large volumes, employing three different trajectories in the quark mass plane, including the physical point. The five different lattice spacings reach down to below 0.04 fm. This became possible by introducing open boundary conditions in time at the smaller lattice...
Using a cluster of Nvidia DGX-1 (8*V100 interconnected by the NVLink), TWQCD Collaboration has generated the first gauge ensemble of $N_f=2+1+1 $ lattice QCD with physical domain-wall quarks, on the $ L^3 \times T = 64^3 \times 64 $ lattice with lattice spacing $a \sim 0.064 $~fm ($ L > 4 $ fm, and $ M_\pi L > 3 $). The gauge ensemble constitutes of ~200 gauge configurations, resulting from...
We investigate finite size effect on hadron masses and decay constants using a subset of the PACS10 configurations which are generated keeping the space-time volumes over (10 fm)^4 at the physical point in 2+1 flavor QCD with the Wilson-type quarks. We have tried two kinds of analyses fixing the $\kappa$ values or the measured axial Ward identity quark masses. The finite size effect is...
The low-lying hadron spectrum has been of tremendous phenomenological significance in resolving the nature of quark masses in strong interaction dynamics. In particular, the pseudoscalar mesons provide the foundation of the framework of chiral perturbation theory, the low-energy effective theory of QCD. Modern lattice calculations of pure QCD now provide excellent precision in the resolution...
The charmonium-like hybrid mesons with $J^{PC}=(0,1,2)^{-+}$ and $1^{--}$ are investigated on anisotropic lattices in the quenched approximation. For these states, we construct spatially extended operators by splitting the $\bar{c}\Gamma c B$-type operators into two parts ($c\bar{c}$ and the chromo-magnetic field strength $B$) with different spatial distances $r$. In the Coulomb gauge, the...
To perform high precision calculations in lattice QCD for observables of physical interest, it is important to determine the lattice spacing with high accuracy. A convenient choice for scale setting is the observable $w_0$ which is based on the Wilson flow. However the value of $w_0$ is not determined experimentally and therefore the value of $w_0$ in physical units has to be be computed by...
The glueballs in the SU(N) Yang-Mills theory are good candidates of dark matter.
An important feature to be discussed is the scattering between dark matter particles, which is constrained by observational data such as the galactic collisions.
In this work, we evaluate the interglueball potential in SU(2), SU(3), and SU(4) lattice gauge theories using the HALQCD method and derive the glueball...
I will discuss my recent works on the determination of resonance properties from the lattice energy levels using the chiral effective field theory.
We study $S$-wave interactions in the $I\left(J^{p}\right)=1/2\left(1/2^{-}\right)$
$\Lambda_{c}K^{+}-pD_{s}$ system on the basis of the coupled-channel
HAL QCD method. The potentials which are faithful to QCD S-matrix
below the $ pD^{*} $ threshold are extracted from Nambu-Bethe-Salpeter
wave functions on the lattice. For the simulation, we employ the (2+1)-flavor
gauge configurations on a...
