Conveners
Heavy Quarks: C1a (Parallel C)
- Francesco Giacomo Knechtli (Bergische Universitaet Wuppertal (DE))
Heavy Quarks: C1b (Parallel C)
- Antonio Vairo (TU Munich)
Heavy Quarks: C2a (Parallel C)
- Roberto Mussa (INFN Torino)
Heavy Quarks: C2b (Parallel C)
- Makoto Oka
Heavy Quarks: C3aI (Parallel C)
- Hee Sok Chung (Korea University)
Heavy Quarks: C3bI (Parallel C)
- Jia-jun Wu
Heavy Quarks: C3bII (Parallel C)
- Christopher Thomas (University of Cambridge)
Heavy Quarks: C4a (Parallel C)
- Wei Wang
Heavy Quarks: C4b (Parallel C)
- Thomas Mehen (Duke University)
Heavy Quarks: C4c (Parallel C)
- K. Utku Can (The University of Adelaide)
Hidden-flavour states are being actively studied at Belle II; the
programme is currently focussed on energy scan data taken above the
Upsilon(4S). Several results will be discussed, including constraints
on the properties of the Upsilon(10753), and analyses combining Belle
and Belle II data. Prospects for further results will also be set out,
including measurements based on the growing...
I will summarise some recent work on charm mesons and charmonium resonances, including exotics, using first-principles lattice QCD calculations. Investigations of S-wave $D\pi$ scattering will be presented, relevant for the $D^{\ast}_0(2300)$ and the enigmatic $D^{\ast}_{s0}(2317)$, where an exotic-flavour virtual bound state was found. Of other results that will be discussed, a highlight is a...
The XYZ exotic states discovered in the hadronic sector with two heavy quarks constitute one of the most important open problems in particle theory. In this talk, I show that an effective field theory derived from QCD, the Born Oppenheimer effective field theory (BOEFT), can describe exotics of any composition. I show the results of general Schr\"odinger coupled equations for arbitrary angular...
We study the properties of the hadron-hadron potentials and quark-antiquark potentials from the viewpoint of the channel coupling[1]. We introduce the effective hadron-hadron potential with coupled to the quark channel.
As an application, we construct a coupled-channel model of $c\bar{c}$ and $D\bar{D}$ to describe exotic hadron $X(3872)$[2].
For the obtained nonlocal potentials, we apply...
In a recent publication [Few Body Syst. 65 (2024) , 59] we derived covariant equations describing the tetraquark in terms of an admixture of two-body states DD ฬ (diquark-antidiquark) and MM (meson-meson), with three-body-like states (where two of the quarks are spectators while the other two are interacting), and qq ฬ annihilation taken into account exactly. These equations have the feature...
Recently, exotic hadrons have attracted much attention. Most exotic hadrons appear near the threshold; $X(3872)$ near the $D\bar{D}^{*}$ threshold, $T_{cc}$ near the $DD^{*}$, $P_{c}$ near the $\Sigma_c \bar{D}^{(*)}$. It is important to study the hadron scattering near threshold in order to clarify the nature of exotic hadrons. Based on this observation, we discuss the general behavior of the...
We will discuss how the confinement potential should be chosen within multi-quark exotic hadrons and what are the effects of the confinement in the spectrum of the tetra-quarks with heavy quark(s). We show the results from the complex scaling method calculation of the tetra-quark systems with the full coupling to the two-meson thresholds.
Since singly heavy baryons and doubly heavy tetraquarks contain two light quarks, they are expected to exhibit well-developed (light-)diquark structures. The properties of light diquarks are affected by spontaneous chiral symmetry breaking and serve as a sensitive probe for investigating the unknown property of the QCD vacuum.
In this talk, we will discuss the spectroscopic properties of...
In recent years, many vector charmonium(-like) states were reported by different electron-positron collider experiments above 4.2 GeV. However, so far, there not only exists sizable tension in the parameters of those states, but there is also no consensus on the number of the vector states in this energy range.
In this talk, we focus on the mass range between 4.2 and 4.35 GeV, conducting a...
We study the system of light mesons, charmonium and glueballs in the flavour singlet channels where they can mix. We use lattice QCD simulations with an almost physical charm quark and three degenerate light quarks for two values of the pion mass ($m_{\pi} \approx 420, 800$ MeV). Thanks to a variational basis which includes mesonic operators with profiles in distillation space, Wilson loops...
A singly heavy baryon can be viewed as a bound state of $N_c-1$ valence quarks in a pion mean-field approach, a heavy quark being regarded as a static color source. This aspect provides a great virtue of dealing with both light and singly heavy baryons on an equal footing. The presence of $N_c-1$ valence quarks polarizes the vacuum and produces pion mean fields, by which the $N_c-1$ valence...
Diquarks are often invoked as QCD effective degrees of freedom to describe baryons as well as certain exotic hadrons. However, even though they are successful in describing many of these low lying QCD states, they and their properties have been difficult to pin down. Here we present progress in studying diquarks in a gauge-invariant setup through embedding them in a parent hadron containing a...
A dominant source of uncertainty in theoretical determinations of ratios of inclusive lifetimes of heavy hadrons are 'Spectator Effects', wherein the light degrees of freedom participate in the decay process. The heavy-quark-expansion describes these effects as matrix elements of four-quark HQET operators in the heavy hadron states of interest. Using a recently developed position-space scheme...
The renormalization group (RG) beta function characterizes the nature of gauge-fermion systems, describes the running of the renormalized coupling, and connects ultraviolet and infrared regimes of quantum field theories. We use the RG beta function as a tool to explore how gauge-fermion systems with SU(3) gauge group change, when the number of fundamental flavors increases. Using lattice field...
The Lambda parameter of three flavor QCD is obtained by computing the running of a renormalized finite volume coupling from hadronic to very high energies where connection with perturbation theory can safely be made.
The theory of decoupling allows us to calculate the running of the
coupling in pure gauge theory. The missing piece is then an accurate matching of a massive three flavor...
The status of narrow states in heavy quark systems is discussed. For states with only heavy valence quarks these are generally states without Zweig allowed decays. The special case of the X(3872) is reexamined in light of new measurements.
For systems with heavy quarks plus light degrees of freedom three systems are discussed: (1) The j=1/2 1P states of heavy-light mesons, (2) The stability...
We present results for dipion transitions between heavy quarkonium states of large principal quantum number for which the multipole expansion does not hold. We combine the QCD effective string theory with the Chiral Lagrangian in order to get the appropriate vertexes. We extend the results to transitions for which the initial estate is a heavy quarkonium hybrid. We observe that the dipion...
We study the light and heavy quark mass dependence of the low-lying charmed mesons in the framework of one-loop HHฯPT. The low energy constants are determined by analyzing the available lattice data from different LQCD simulations. Model selection tools are implemented to determine the relevant parameters as required by data with a higher precision. Discretization and other effects due to the...
I will discuss recent progress in heavy quarkonium calculations from lattice QCD. Fully relativistic QCD on fine lattices -- with physical light and heavy quark masses, and realistic sea quark content -- allows precise determination of a number of charmonium and bottomonium properties such as meson masses and decay constants, which provide stringent tests of the strong interaction. Meson...
In this talk, I will present our latest theoretical results regarding the exclusive double J/psi production at the B factory.
I will elucidate the reasons why the conventional NRQCD-based predictions for this process exhibit a notably poor convergence. I will then demonstrate that this convergence can be significantly enhanced by employing an improved NRQCD factorization approach. I will...
We resum the double logarithmic singularities at threshold in heavy quarkonium fragmentation functions based on the nonrelativistic QCD factorization formalism. At fixed order, we reproduce the double logarithmic singularities known at next-to-leading order accuracy. Unlike fixed-order calculations, the resummed fragmentation functions we obtain are smooth functions that no longer contain...
It was found that, using nonrelativistic QCD factorization, the predicted $\chi_{cJ}$ hadroproduction cross section at large $p_T$ can be negative. The negative cross sections originate from terms proportional to plus function in $^3P_{J}^{[1]}$ channels, which are remnants of the infrared subtraction in matching the $^3P_{J}^{[1]}$ short-distance coefficients. In this article, we find that...
The self-interacting nature of gluons remains one of the most fascinating characters of QCD. An observation of glueball states will be the ultimate validation of low energy QCD. The radiative decay of the $J/\psi$ meson is a gluon-rich process and is therefore regarded as an ideal place for searching and studying glueballs.
Based on $(10087\pm44)\times10^{6}$ $J/\psi$ events collected with...
We present the first observation of the rare ฮทโฮผ^+ ฮผ^- ฮผ^+ ฮผ^- double-Dalitz decay. The analysis is based on data collected by the CMS experiment at the CERN LHC operating at the centre-of-mass energy of โs=13 TeV. The data sample was collected with high-rate muon triggers for an integrated luminosity of 101 fb^(-1).
The branching fraction of the ฮทโ4ฮผ decay is measured relative to the ฮทโ2ฮผ...
The production of particles containing heavy quarks (beauty and charm) from proton and heavy ion collisions is extensively studied at the LHCb (Large Hadron Collider beauty) experiment. Studying the effect of multiplicity on the production of particles containing heavy quarks, probes the production mechanism of such particles.
The LHCb experiment is unique in its ability to observe...
We explore the distribution of the Lee-Yang zeros around the critical point that appears in the heavy-quark region of QCD at nonzero temperature in lattice numerical simulations. With the aid of the hopping-parameter expansion that is well justified around the critical point in our setting, our numerical analysis is capable of analyzing the partition function in the complex parameter plain...
The study of CP violation is critical for understanding the asymmetry between matter and antimatter in the universe. This talk presents the CP violation in $B_s^0 \to J/\psi\,\phi$ decays measured with the CMS detector at the LHC using Run 2 data. A full angular analysis of the decay is performed, extracting several key parameters such as the CP-violating phase, the amount of direct CP...
In this talk, I will introduce a novel framework proposed to extract near-threshold resonant states from finite-volume energy levels of lattice QCD and is applied to elucidate structures of the positive parity $D_s$. The quark model, the quark-pair-creation mechanism and $D^{(*)}K$ interaction are incorporated into the Hamiltonian effective field theory. The bare $1^+$ $c\bar s$ states are...
๏ทThis talk present the study on the next-to-next-to-leading-order (NNLO) QCD corrections to $e^+e^- \to J/\psi+\eta_c$ and $e^+e^- \to J/\psi+J/\psi$ at the $B$ factories, based on our two published work :
๏ทJHEPย 02ย (2024)ย 055e-Print:ย 2311.04751ย [hep-ph], and JHEPย 02ย (2023)ย 049, e-Print:ย 2212.03631ย [hep-ph].
For $e^+e^- \to J/\psi+\eta_c$ is enhanced by about $17\%$, and the perturbative...
In recent experiments in the heavy quark sector, various candidates of exotic hadrons have been observed. Most of exotic hadrons are discovered near the threshold of two-body scattering as represented by $T_{cc}$ and $X(3872)$ [1,2]. Such near-threshold states are empirically considered as hadronic molecules [3]. To focus on the molecular structure, it is useful to calculate the compositeness,...
The doubly charmed tetraquark $T^+_{cc}$ recently discovered by the LHCb Coll. is studied by using (2+1)-flavor lattice QCD simulations with nearly physical pion mass $m_\pi=146$ MeV. The interaction between $D^*$ and $D$ in the isoscalar and $S$-wave channel extracted from the hadronic spacetime correlation by the HAL QCD method is attractive and leads to a near-threshold virtual state with a...
We have studied the mass spectra of doubly charm pentaquark states in the $\Lambda_{c}^{(*)}D^{(*)}$ and $\Sigma _{c}^{(*)}D^{(*)}$ channels with various quantum numbers in QCD sum rules. We use the parity projected sum rules to separate the contributions of negative and positive parities from the two-point correlations induced by the pentaquark interpolating currents. Our results show that...
The T_cc^+ is a a doubly charmed tetraquark that lies very close to the D^* D meson thresholds. As such it can be described as a molecular bound state in an effective field theory (EFT) of heavy mesons. An EFT calculation of the width is in excellent agreement with experiment and also successfully reproduces the invariant mass spectrum of the D mesons in the three body decays of the T_cc^+....
We have investigated the internal structure of the open- and hidden-charmed($DD^โ/D\bar{D}^โ$) molecules in the unified framework. We first fit the experimental lineshape of the $T^+_{cc}$ state and extract the $DD^โ$ interaction, from which the $T^+_{cc}$ is assumed to arise solely. Then we obtain the $D\bar{D}^โ$ interaction by charge conjugation. Our results show that the $D\bar{D}^โ$...
In this talk, I will present a novel effective-field-theory-based approach for extracting two-body scattering information from finite volume energies. By explicitly incorporating one-pion exchange, we overcome the challenging left-hand cut problem in Lรผscherโs method and can handle finite volume energy levels both below and above the left-hand cut. Additionally, we utilize the plane wave basis...
Recent measurements of polarization phenomena in relativistic heavy ion collisions have aroused a great interest in understanding dynamical spin evolution of the QCD matter. In particular, the spin alignment signature of $J/\psi$ has been recently observed in Pb-Pb collisions at LHC, which may infer nontrivial spin transport of quarkonia in quark gluon plasmas. Consequently, we study the...
Understanding hadron formation is one of the fundamental goals of hadron physics. It is essential way to investigate the effective degrees of freedom of hadrons such as the quark-quark correlation, namely the diquark correlation. Spectroscopic observations of charmed and multi-strange baryons can provide a unique opportunity to study diquark correlation. Systematic studies of charmed and...
Inย 2020-24,ย the observation of $c\bar c c\bar c$ exotic hadrons (di-$J/\psi$) was reported by LHCb, CMS, and ATLAS. Their energies are above the 2$m(J/\psi)$ threshold, $X(6200, 6600, 6900)$.ย Here, we investigate these states, focusing on the quark-Pauli blocking effect. We show that this effect can make a structure in the S-wave $c\bar c c\bar c$ systems. The Pauli blocking over the quarks...
We present a method to compute lightcone distribution amplitudes (LCDAs) of heavy meson within heavy quark effective theory (HQET). Our method utilizes quasi distribution amplitudes (quasi-DAs) with a large momentum component Pz. We point out that by sequentially integrating out Pz and mH, one can disentangle different dynamical scales. Integrating out Pz allows to connect quasi-DAs to QCD...
