Conveners
Quarkonia: I
- Ralf Rapp (Texas A&M University)
Quarkonia: II
- Ramona Vogt (LLNL)
Quarkonia: III
- Yasuyuki Akiba (RIKEN)
Quarkonia, i.e. bound states of $b\bar{b}$ and $c\bar{c}$ quarks, are powerful observables to study the properties of nuclear matter under extreme conditions. The formation of a Quark-Gluon Plasma (QGP), which is predicted by lattice calculations at high temperatures as reached at LHC energies, has a strong influence on the production and behavior of quarkonia. A suppression, due to the color...
The experimentally observed dissociation and regeneration of bound quarkonium states in heavy-ion collisions provide a powerful tool to probe the dynamics of the hot, dense plasma. These measurements are sensitive to the effects of color screening, color recombination, or other, new suppression mechanisms. In the large-statistics Run 2 lead-lead and proton-lead collision data, these phenomena...
Heavy quarkonium related observables are very useful to obtain information about the medium created in relativistic heavy ion collisions. In recent years the theoretical description of quarkonium in a medium has moved towards a more dynamical picture in which decay and recombination processes are very important. In this talk we will discuss the equations that describe the evolution of the...
In this study, we investigate the real-time evolution of quarkonium bound states
in a quark-gluon plasma in an improved QCD based stochastic potential model. This
model describes the quarkonium dynamics in terms of a Schrรถdinger equation with
an in-medium potential and two noise terms encoding the residual interaction
between the heavy quarks and the medium. The time evolution described by...
Understanding experimental results on nuclear modification factors of heavy quarkonia as well as open heavy mesons is complicated due to the interplay between the cold and hot medium effects. In order to disentangle these two effects it is crucial to have a good understanding of thermal behavior of quarkonia and heavy quarks in the hot medium. The quarkonium spectral function is of the most...
Quarkonia breaking in nucleus-nucleus collisions is a powerful tool to probe
density and temperature of the medium created in heavy ion collisions. Forward rapidity measurements in $p(d)$+Au collisions are essential to understand how quarkonia states are affected by initial state effects, formation time, and local particle multiplicity. Earlier measurements in Au+Au collisions showed a...
Measurements of quarkonium production play an important role in understanding the properties of the Quark-Gluon Plasma (QGP) created in relativistic heavy-ion collisions. Quarkonium suppression in the medium due to the color screening effect has been proposed as a direct signature of the QGP formation. However, other effects, such as cold nuclear matter (CNM) effects and regeneration, add...
The production cross sections of the $\Upsilon(1S)$, $\Upsilon(2S)$, and $\Upsilon(3S)$ states were measured separately using the CMS experimental apparatus, in pp, pPb, and PbPb collisions at 5.02 TeV. New results on the production of the three upsilon states in pPb are reported, including cross sections as a function of transverse momentum (p$_T$) and rapidity ($y$). The data show a stronger...
Bottomonium suppression has long been discussed as a probe for the quark-gluon plasma generated in ultra-relativistic heavy ion collisions. The use of a realistic hydrodynamic background which is anisotropic in momentum space has shown to reproduce experimental data for various windows across each experiment. We have recently expanded our model to incorporate a realistic lattice-vetted...
Quarkonium production in high-energy hadronic collisions provides a fundamental test of QCD. Its modification in a nuclear medium is a sensitive probe of the space-time temperature profile and transport properties of the QGP, yielding constraints complementary to the ones obtained form the quenching of light and heavy flavor. We will present new results for the suppression of high transverse...
The heavy-quark potential is a highly versatile theoretical tool. It allows one to summarize many aspects of the intricate interactions between a QQbar bound state and its surrounding medium in a single complex valued quantity. It is systematically defined from QCD [1,2] and at the same time provides an intuitive understanding of the physics of in-medium quarkonium modification. I.e. it offers...
New results on quarkonia production in proton-lead collisions at LHCb at 8.16 TeV nucleon-nucleon center-of-mass energy will be presented. Measurements include J/psi and psi', where the prompt and from-b-decay components can be disentangled, and the 1-- bottomonia states. The large data sample allows the determination of nuclear modification factors with high accuracy.
LHCb has the unique...
The study of quarkonium production in proton-nucleus collisions is an important tool to investigate cold nuclear matter (CNM) effects. Mechanisms such as the modification of the parton distribution functions in nuclei, the presence of a color glass condensate or coherent energy loss of the $c\overline{c}$ pair in the medium have been employed to describe J/$\psi$ production in proton-nucleus...
A multi-dimensional analysis of prompt charmonia in pp and pPb collisions at 5.02 TeV with the CMS detector is presented. The pPb differential cross-sections of prompt J/$\psi$ are shown in a wide kinematic region, for transverse momentum p$_T$ spanning from 2 to 30 GeV/c and a rapidity interval between -2.87 to 1.93 in the center of mass of the collision. The ratio of yields in forward...
Heavy quark pair production in minimum bias p+p and p+A collisions has been studied extensively in the CGC framework and compared successfully to both the RHIC and LHC data on $J/\psi$ production [1, 2], $\psi(2S)$ production [3] and $D$-meson production [4]. We first present an update in this framework based on comparisons to the latest LHC and RHIC data on p+p and light-heavy ion collisions....
An improved version of the color evaporation model (ICEM) has been introduced to describe heavy quarkonium production [1]. In contrast to the traditional color evaporation model, the constraint was imposed that the invariant mass of the intermediate heavy quark-antiquark pair must be larger than the mass of produced quarkonium. A momentum shift between heavy quark-antiquark pair and the...
Quarkonia can be used as probes of quark-gluon plasma (QGP), a hot nuclear environment produced in heavy ion collisions. Quarkonia become unbound or "melt" at sufficiently high temperature due to the significant screening of the color attraction. In this sense, quarkonia can be thought of as thermometers of QGP. But extracting the melting temperature from experimental measurements is much...
A wealth of data on charmonium production from the major LHC experiments has provided strong evidence for (re-)generation as a dominant production mechanism at low transverse momentum. To make further progress in the understanding of the underlying physics we present an important extension of the statistical hadronisation model to describe J/$\psi$ transverse momentum distributions based on...
