Hirschegg 2024 - Strong interaction physics of heavy flavors

This talk will review the prospect to use heavy flavor hadron yields and spectra as probes of deconfinement. It will also review the approach using the statistical hadronization model, the SHMc, to describe heavy flavor observables. the necessary input, i.e. the open charm cross section and the knowledge about thermalization of charm in the QGP will be presented. A few results of the SHMc will...

The respective contributions of cold-matter and hot-medium effects to the suppression of Y(1S) and Y(2S) mesons in p-Pb collisions at energies reached at the Large Hadron Collider (LHC) are investigated. Whereas known alterations of the parton density functions in the lead nucleus and coherent parton energy loss account for the leading fraction of the modifications in cold nuclear matter...

The initial stages of ultra-relativistic nucleus-nucleus collisions are not well constrained. In particular, the number of initially produced heavy-quark pairs, part of any initial conditions required for modeling, is not well known. When the heavy-quark pair production in nucleus-nucleus collisions is estimated based on an extrapolation from proton-proton collision measurements, this is...

We present results for bottomonium suppression in the QGP based on pNRQCD and the open quantum system framework. We solve the corresponding Lindblad equation for the quarkonium density matrix to obtain results for the nuclear modification factor. We extend previous studies by including the three-loop potential from pNRQCD for the singlet and octet into the simulation pipeline. We find good...

Understanding the line shape of the cs and double-cs states, and searching for new resonances, are topics of great interest. Recent results in hadron spectroscopy are going to be presented. This talk covers in particular the most recent achievements by using the complete Belle and Belle II data sets in the analyses of the continuum, ISR, and gamma-gamma processes. Future perspectives by...

A `second charm revolution' was sparked with the discovery of new 'XYZ' states, such as the X(3872) or the Y(4260) by the B factories Belle and BABAR, which do not fit into the conventional picture of quark-antiquark bound systems. Recently, a number of further, non-conventional bound states have been seen by various experiments in several different production channels. In this talk, I will...

In the last years, several exotic states were observed in the charm sector; such particles cannot be interpreted as regular baryons or mesons and are thought to be either quark bags or molecular states. To unveil their nature, it is crucial to experimentally constrain the strong force that governs the interaction between the charm hadrons and other hadrons, for instance, via the measurement of...

The formation of hadrons is a fundamental process in nature that can be investigated at particle colliders. This seminar focuses on the investigation of hadronization processes, particularly those involving heavy quarks, in various collision systems ranging from e+e− to proton–proton (pp) and nucleus–nucleus (AA) collisions. In recent years, the paradigm that heavy-quark hadronisation should...

On the basis of scales separation, we construct a general nonrelativistic effective field theory treatment for exotics XYZ states called BOEFT. Scale factorization introduces systematicity and simplicity allowing model independent predictions. The dynamics contained in the nonperturbative low energy correlators is addressed with new and tailored lattice QCD computational tools. We will show...

The charm and bottom meson sectors offer a rich arena in which to study strong interaction physics. I will describe recent lattice calculations in heavy
meson spectroscopy and radiative transitions and offer some perspectives for
future study.

I discuss the basic principle as well as typical problems, when computing masses of hadrons, in particular heavy exotic mesons, with lattice QCD. I also present selected recent lattice QCD results for heavy exotic mesons. I focus on tetraquarks composed of two heavy anti-bottom quarks and two lighter quarks.

In this talk I will discuss our investigations into the proposed, deeply-bound, $T_{bb}$ and $T_{bbs}$ tetraquark states. For our most-recent determination the focus will be on the influence of the lattice NRQCD b-quark tuning and furthermore outlining the pertinent systematics in our final mass determinations. I will then illustrate our ongoing efforts to further reduce these systematics,...

I will review lattice QCD results on the doubly charm tetraquark and discuss the observed
dependence on the masses of light and charm quarks. The DD* scattering amplitude at larger-than physical pion masses has a so-called left-hand cut that opens slightly below threshold due to pion exchange. I plan to discuss also how to incorporate the effects of this cut on the analysis of the...

Since the experimental discovery of the first tetraquarks in 2003, there
has been a lot of excitement around this topic from the theoretical
as well as the experimental side. To study the properties of
these four-quark states we employ hadronic bound state
equations, i.e., Faddeev or Bethe-Salpeter equations. In this talk we will
present our results for the mass spectra and internal...

In this talk, I discuss progress developing and applying the relativistic field-theoretic three-particle finite-volume scattering formalism to systems of nondegenerate mesons. In particular, I focus on the recently developed formalism for $DD\pi$ systems in the charm C = 2 sector. This includes the isospin-0 channel, in which the recently discovered doubly-charmed tetraquark $T_{cc}(3875)^+$...

A brief overview of the derivation of the manifestly relativistic-invariant expression for the Lellouch-Lüscher factor in three-particle decays is given. Furthermore, the framework has been explicitly applied to the decay process of a kaon into three (non-identical) pions at leading order. The role of the three-particle force is investigated in detail.

Inspired by the recent precise data, we perform model-independently an isospin decomposition of the timelike octet baryons electromagnetic form factors. As noted in our previous work, the relative magnitude of isoscalar and isovector component is determined with the input of data on various isospin channels. Herein we further assert that their relative phase can be constraint by the phase...

Simulating quantum systems in a finite volume is a powerful theoretical tool for extracting information about them. The observation that the real-world properties of states are encoded in how their energy levels change with the size of the volume gives rise to a versatile approach that has applications in nuclear physics, hadron physics, and is also relevant for simulations of cold atomic...

Elastic nucleon-pion scattering amplitudes are computed using lattice QCD on a single ensemble of gauge field configurations with $N_{\rm f} = 2+1$ dynamical quark flavors and $m_{\pi} = 200~{\rm MeV}$. The $s$-wave scattering lengths with both total isospins $I=1/2$ and $I=3/2$ are inferred from the finite-volume spectrum below the inelastic threshold together with the $I=3/2$ $p$-wave...

The quest of unraveling the nature of excited hadrons necessarily involves determination of universal (reaction independent) parameters of these states. Such determinations require input, either from experiment or theory. The challenge in answering these questions from theory arises from the very structure of the theory of strong interaction — QCD. Lattice gauge theory is the only tool...

This talk presents results of the first coupled-channel meson-baryon Σπ − N K̄ computation from lattice QCD
in the Λ(1405) region. Correlation functions were calculated using a single ensemble with a pion mass mπ = 200
MeV and kaon mass mK = 487 MeV, including single- and multi-hadron operators and the finite-volume energy
spectra were extracted. The Lüscher method was employed to study...

This talk will focus on X(3872) and other multiquark candidate states observed in B meson decays and focus on results from Belle and Belle II. The results will be put into perspective by comparing to states observed at other experiments. Implications of the observed spectroscopical pattern will be discussed and conclusions for the underlying potential will be drawn. Unresolved puzzles and...

The presentation will provide a review of the latest discoveries in heavy-flavor hadron spectroscopy at LHCb, particularly focusing on exotic multiquark states.
Key updates will include the recent evidence for a J/ψK0S structure in B0 decays, the groundbreaking observation of the first doubly charged tetraquark,
and insights from the ongoing search for pentaquarks in prompt production within...

In this talk I concentrate on two very important coefficients in the open-quantum system description of quarkonium in media, namely the mass shift \gamma and the width \kappa. I illustrate recent developments related to the differences in the definitions pertaining to heavy quarkonia and to isolated heavy quark and I discuss their impact on perturbative, lattice and holographic determinations.

Quarkonia, the bound states of heavy quark-antiquark pairs, have proven to be crucial probes for studying quark-gluon plasma. The color screening properties of the QGP weaken the interaction between quark-antiquark pairs, leading to the suppression of quarkonia yields within the QGP. We present some preliminary results on the fate of quarkonia bound states in the QGP by performing spectral...

I will review the broad aspects of quarkonium production at the LHC and compare to the statistical hadronization model predictions. The focus will be on pT-integrated yields and will include open-charm hadrons and also comparisons to other approaches.

This talk summarizes the efforts of the EMMI Rapid Reaction Task Force on “Suppression and (re)generation of quarkonium in heavy-ion collisions at the LHC”, centered around their 2019 and 2022 meetings. It provides a review of theoretical approaches, and semi-classical and quantum approaches for the dynamical evolution of quarkonia in the quark-gluon plasma as probed in high-energy heavy-ion...