Conveners
Heavy quarks: C1a
- Geoffrey Bodwin (Argonne National Laboratory)
Heavy quarks: C1b
- Antonio Vairo
Heavy quarks: C2a
- Antonio Vairo
Heavy quarks: C2b
- Thomas Mehen (Duke University)
Heavy quarks: C3a
- Yan-Qing Ma (PKU)
Heavy quarks: C3b
- Joan Soto (Universitat de Barcelona)
Heavy quarks: C5a
- Joan Soto (Universitat de Barcelona)
Heavy quarks: C5b
- Geoffrey Bodwin (Argonne National Laboratory)
In this talk we explain how to obtain the renormalization group improved expressions of the Wilson coefficients of the HQET Lagrangian with leading logarithmic approximation to ${\cal O}(1/m^3)$, which includes the heavy quark chromopolarizabilites. For the spin-independent sector, our analysis includes the effects induced by spectator quarks. We observe that the numerical impact of these...
We discuss the leptonic decay constants of heavyโlight mesons by means of Borel QCD sum rules in the local-duality (LD) limit of infinitely large Borel mass parameter. In this limit, for an appropriate choice of the invariant structures in the QCD correlation functions, all condensate contributions vanish and all nonperturbative effects are contained in only one quantity, the effective...
We revisit rare radiative leptonic decays B_(s,d) โ ฮณee and B_(s,d) โ ฮณฮผฮผ in the standardmodel and provide the updated estimates for various differential distributions (the branching ratios, the forward-backward asymmetry, and Rฮผ=e, the ratio of the differential distribution for muons over electrons in the final state). The new ingredients of this work compared to the existing theoretical...
We describe the recent theoretical results on |Vxb| determinations, as well as the status and prospective of the related inclusive/exclusive puzzle
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We analyze the issue of lepton flavor non universality in b -> s l l decays in non-minimal 331 models
The BESIII experiment at BEPCII accumulated the world's largest e+e- collision samples at 3.773 and 4.178 GeV. In (semi-)leptonic decay aspect, we have studied the purely leptonic decays D+ -> tau+v and D_S+->mu+v, and the semi-leptonic decays of D0 to K(pi)- mu+v, D+ -> pi0 mu+v, D+(_S) -> eta(') ev and D_S+->K(*)0 e+v. We will report the improved measurements of the branching fractions of...
We study the $C=1$, $S=-2$, $I=0$ sector, where five $\Omega_c$ states have been recently observed by the LHCb Collaboration [1]. In Ref. [2] a unitarized meson-baryon model was solved by adopting a one-subtraction renormalization scheme taking, as bare meson-baryon interaction, an extended Weinberg-Tomozawa interaction consistent with both chiral and heavy-quark spin symmetries. This ${\rm...
We calculate the spectrum of charmed baryons on $32^3\times64$, $2+1$-flavor lattice QCD ensembles generated by the PACS-CS Collaboration. Calculations are done with almost physical light quarks, $m_\pi$ ~ 156 MeV, and physical strange and charm quarks. A relativistic heavy-quark action is used for valance charm quarks to suppress the systematic errors. A two-fold variational analysis is...
In this talk, I will present the first set of next-to-next-to-leading order (NNLO) fragmentation functions (FFs) describing the production of charmed-meson $D^{*}$ from partons [Phys.Rev. D97 (2018) no.7, 074014]. Exploiting the universality and scaling violations of FFs, we extract the NLO and NNLO FFs through a global fit to all relevant data sets from single-inclusive $e^+e^-$ annihilation....
In the last decade, charmed and bottom meson spectroscopy have seen great success in experimental sector. Experiments like LHCb, Babar etc are providing many new states which are being added to their spectroscopy. Newly predicted states like Ds(3040), Ds(2700), Ds(2860) and many more still need to be assigned their proper place in the spectroscopy. So we studied the decay constant and the...
The Belle II experiment, now operating at the KEK laboratory in Japan, is a substantial upgrade of both the Belle detector and the KEKB $e^+ e^-$accelerator. It aims to collect 50 times more data than existing B-Factory samples. Belle II is uniquely capable to study the so-called "XYZ" particles: heavy exotic hadrons consisting of more than three quarks. First discovered by Belle, these now...
Recently, an unapproved CMS study indicates that there appears to be a QCD bound state approximately 300MeV below the 2$\eta_b$ threshold. An obvious candidate for this would be a stable (in QCD) four quark bound-state composed of two bottom-quarks and two anti-bottom quarks: $bb\bar{b}\bar{b}$. This system has generated significant attention in the literature from model-dependent...
In this talk I will explain how to obtain the perturbative NNNLO heavy quarkonium spectrum for equal and different masses. This computation allows to determine the charm and bottom quark masses from the bottomonium, charmonium and $B_c$ systems. The use of the renormalon subtracted scheme, provides control over the divergence of the perturbative series due to the pole mass renormalon. On top...
I review the status of the resummation of large logarithms in the spectrum of heavy quarkonium. The seaked precision is NNNLL. Special emphasis is put in P-wave states for which complete results to this order are presented.
The perturbative accuracy for bottomonium observables has recently been extended to next-to-next-to-next-to-leading order. Assuming the hierarchy $\Lambda_\text{QCD}\ll m_bv^2$ holds, non-perturbative corrections take the form of local condensates. I determine higher-order corrections in this approach and assess its validity by studying the convergence of the series. In particular, the...
The typical energy scale of heavy hadron spectroscopy makes the system accessible to perturbative calculations in terms of non-relativistic QCD. Within NRQCD the predictions of heavy quarkonium energy levels rely on the accurate description of the static QCD potential $V_{\rm QCD}(r)$. Most recent calculations computed the energy levels of the lower-lying bottomonium states up to...
We determine the charm quark mass mc(mc) from QCD sum rules of moments of the vector current correlator calculated in perturbative QCD. Only experimental data for the charm resonances below the continuum threshold are needed in our approach, while the continuum contribution is determined by requiring self-consistency between various sum rules, including the one for the zeroth moment. Existing...
This talk considers exotic hadrons containing two heavy quarks (or a heavy quark and a heavy antiquark). It is argued on very general model-indpendent grounds that in the heavy quark limit such exotic hadrons must exist as parametrically narrow states. Moreover, it is shown that there in this limit there will be multiple exotic resonances with the same quantum numbers and that some of these...
Properties of resonances and excited states near decay thresholds are encoded
in hadronic scattering amplitudes, which can be extracted from the finite volume
spectrum using (extensions of) Lueschers method. We discuss how to reliably
extract the finite volume spectrum above strong-interaction decay thresholds
from lattice QCD simulations. Preliminary results for such spectra in
various frames...
While many properties of the vector charmonium first excitations are yet to be determined, enhancements at unexpected energies are intriguing, alias the $Y$ states. In order to understand the naturally unquenched mesonic line-shapes, the influence of the most relevant hadronic decay channels must be taken into account. Within an unitary effective approach we present results where mesonic loops...
In recent years, a new class of exotic charmonium-like states, also referred to as XYZ states, have been discovered. Being incompatible with the simple quark-antiquark model, they are candidates for non-standard hadrons such as tetraquarks, meson molecules, and hybrids. The BESIII experiment operating at the electron-positron collider BEPCII at IHEP (Beijing) has accumulated a large amount of...
We present an effective field theory calculation of the lower lying heavy hybrid spectrum, which includes mixing with heavy quarkonium states as a novel feature. Spin zero (one) hybrids turn out to mix with spin one (zero) quarkonia, which is intrumental to explain apparent spin symmetry violating decays of certain XYZ resonances that have been identified as hybrid states. We also present some...
We study tetraquark resonances for a pair of static quarks $\bar{b}\bar{b}$ in presence of two light quarks $ud$ based on lattice QCD potentials. The system is treated in the Born-Oppenheimer approximation and we use the emergent wave method. We focus on the isospin $I=0$ channel but take different angular momenta $l$ of the heavy quarks $\bar{b}\bar{b}$ into account. Further calculations have...
We present energy spectra of various tetraquark states with one or more heavy quarks using lattice quantum chromodynamics. These calculations are performed on
$N_f=2+1+1$ MILC ensembles at lattice spacings ~ 0.12, 0.09 and 0.06
fm. A relativistic action with overlap fermions is employed for the
light and charm quarks while a non-relativistic action with
non-perturbatively improved coefficients...
The BornโOppenheimer approximation is the standard tool for the studying systems in atomic molecular systems. It is founded on the observation that the energy scale of the electron dynamics in a molecule is larger than that of the nuclei. A very similar physical picture can be used to describe QCD states containing heavy quarks as well as light quarks and gluonic excitations. In this talk I...
It is fairly well established that X(4260) does not correspond, regarding its mass and transition properties, to a conventional c-cbar state of the type provided for example by the Cornell [1] or the Godfrey-Isgur [2] models. This has motivated the development of other descriptions involving Fock space components (tetraquarks, meson molecules, hybrids...) different from c-cbar (see for example...
The potential between heavy hadrons due to pion-exchange can be obtained in the quark model (as a straightforward generalisation of the $NN$ potential), or from heavy quark and chiral symmetries. The two approaches are shown to be fundamentally equivalent, and general results applicable to both are discussed. Expressions are derived for the pion-exchange potential between any constituents,...
A review and comparison of different models for the LHC_b pentaquarks and different predictions will be given. Predictions also for hidden bottom pentaquark states will be given. New predictions for the most intresting channels where to look for new pentaquark states will be discussed, as it can be intresting also for the experimentalists. The second part of the talk will be devoted to...
The $q\bar q s\bar s$ and $q\bar q c\bar c$ $J^{PC}=1^{--}$ 4-body systems are investigated by a simplified quark cluster model, where the 14 relevant channels are coupled. In each of the systems, one or more poles have been found. For the $q\bar q c\bar c$, a pole appears close to the thresholds and its width is found to be small. The poles found in the $q\bar q s\bar s$ have rather larger...
At present large data samples were accumulated at the BESIII detector, operated in the upgraded electron positron collider in Beijing (BEPC-II), in the energy region of 2.0-4.6 GeV, which provides a super opportunity in the study of light hadron spectra and charmonium(-like) decays. We summarize the isospin violations in recent BESIII analyses, which are divided into three categories: isospin...
Studies of the production of heavy quarkonium states are very important to improve our understanding of QCD and hadron formation, given that the heavy quark masses allow the application of theoretical tools less sensitive to nonperturbative effects. Thanks to a dedicated dimuon trigger strategy, combined with the record-level energy and luminosity provided by the LHC, the CMS experiment has...
A global analysis of ATLAS and CMS measurements reveals a startling observation: the directly-produced mid-rapidity J/ฯ, ฯ(2S), ฯc1, ฯc2 and ฮฅ(nS) have differential cross sections of seemingly identical shapes, when presented as a function of the mass-rescaled transverse momentum, pT/M. This universal momentum scaling pattern, together with the absence of strong polarizations of S-wave mesons...
NRQCD factorization is currently the most widely used theory to describe heavy quarkonium production. Although NRQCD has got lots of successes, it also faces some notable difficulties right now. A possible reason to explain these difficulties is that, because of soft gluons radiation at the hadronization stage, convergence of velocity expansion in NRQCD is too bad. In the soft gluon...
Logarithms of the hard-scattering scale that appear in light-cone
amplitudes can be resummed by making use of the
Efremov-Radyushkin-Brodsky-Lepage (ERBL) evolution equation for the
light-cone distribution amplitude (LCDA). The standard method for
carrying out the evolution is to decompose the LCDA in a series of
eigenfunctions of the lowest-order evolution kernel (Gegenbauer
polynomials)....
We study the spin-splitting in the spectrum of heavy quarkonium hybrids using non-relativistic effective theory. After sequentially integrating out modes at the scales m_Q, m_Q v and Lambda_QCD, we obtain the spin-dependent potential to order 1/m_Q^2, in which non-perturbative contributions are given by gluonic correlators. With the hybrid potentials obtained from the lattice, we solve the...
A number of new states have been observed from the Belle experiment
ever since the discovery of the X(3872) in 2003
and related studies are still ongoing by using full Belle data set.
Here we report some of recent results on the charmonium and
charmoniumlike states, and also open charm production based on a large data sample recorded at the
Belle detector at the KEKB...
The masses of the low lying charmonium states, namely, the $J/\Psi$, $\Psi(3686)$, and $\Psi(3770)$ are shifted downwards due to the second order Stark effect. In $\bar p + \text{Au}$ collisions at $6-10$~GeV we study their in\,-\,medium propagation. The time evolution of the spectral functions of these charmonium states is studied with a Boltzmann\,-\,Uehling\,-\,Uhlenbeck (BUU) type...
This talk will describe new tests of quarkonium production using quarkonia that are produced within jets. We study the distribution in the fraction z of a jet's longitudinal momentum carried by the quarkonium. The z distribution is sensitive to the underlying NRQCD production mechanism. Analytic calculations of the z distributions in SCET that incorporate Next-to-Leading-Log (NLL) resummation...
The PANDA experiment represents the central part of the hadron physics programme
at the new Facility for Antiproton and Ion Research (FAIR) under construction at
GSI/Darmstadt (Germany). The multi-purpose PANDA detector in combination with an
intense and high-quality antiproton beam allows for coverage of a broad range of
different aspects of QCD, and it is best suited for charmonium...
Charmed mesons and baryons provide an ideal laboratory to probe non-perturbative strong interaction dynamics. The LHCb experiment, with its excellent vertexing, tracking and particle identification capabilities, is very suitable for the study of charmed mesons and baryons, and interesting results in this area have been obtained from several recent analyses of LHCb data. Following the discovery...
