Conveners
Parallel 3: HF & QQbar: Heavy flavour production
- Elena Gonzalez Ferreiro (Universidade de Santiago de Compostela (ES))
Parallel 3: HF & QQbar: Heavy flavour flow
- Andrea Dainese (INFN - Padova (IT))
Parallel 3: HF & QQbar: Heavy flavour in the QGP
- Roberta Arnaldi (Universita e INFN Torino (IT))
Parallel 3: Jets & high-pT: High-pT correlations
- John William Harris (Yale University (US))
Parallel 3: HF & QQbar: Quarkonia
- Carlos Lourenco (CERN)
Parallel 3: HF & QQbar: Heavy flavour
- Jean-Philippe Lansberg (IPN Orsay, Paris Sud U. / IN2P3-CNRS)
Parallel 3: HF & QQbar: Charm
- Enrico Scomparin (Universita e INFN Torino (IT))
Parallel 3: HF & QQbar
- Cynthia Hadjidakis (Centre National de la Recherche Scientifique (FR))
The PHENIX Experiment measures electrons from heavy flavor decays at mid-rapidity |y|<0.35 in a range of 1<pT<7GeV/c. Separated charm and bottom yields are obtained by unfolding distance of the closest approach distributions. Charm and bottom quark yields are measured in p+p and Au+Au collisions obtained from the high luminosity RHIC runs taken in 2015 and 2014 respectively. The results in p+p...
Recent RHIC and LHC results show that the nuclear modification factors of open charm hadrons at high transverse momenta as well as their elliptic flow are similar to those of light flavor hadrons, indicating that charm quarks also interact very strongly with the Quark Gluon Plasma (QGP). During interactions, charm quarks suffer from substantial energy loss and gain significant elliptic flow....
The transverse momentum spectra of $D^0$ mesons from b hadron decays are measured in pp and PbPb collisions at a nucleon-nucleon center of mass energy of 5.02 TeV with the CMS detector at the LHC. The measurement is performed in the $D^0$ $p_T$ range of 2–100 GeV /c and in the rapidity range of |y| < 1. The $D^0$ mesons from b hadron decays are distinguished from prompt $D^0$ mesons by their...
Beauty quark production in heavy-ion collisions is considered to be one of the key measurements to address the flavour-dependence of in-medium energy loss in heavy-ion collisions. On the other hand, the measurement of the production of strange beauty mesons can provide fundamental insights into the relevance of mechanisms of beauty recombination in the quark-gluon plasma. In this talk, CMS...
Charm quarks, owing to their large mass, are produced predominantly during the initial hard scatterings in heavy-ion collisions and therefore can be a valuable tool to study the early time dynamics of these collisions. The rapidity odd directed flow of particles produced at mid-rapidity in heavy-ion collisions originates from a tilt in the reaction plane of the thermalized medium caused by...
It has been proposed that the azimuthal distributions of heavy quark-antiquark pairs may be modified in the medium of a heavy-ion collision. This assumption is tested through next-to-leading order (NLO) calculations of the azimuthal distribution, $d\sigma/d\phi$, including transverse momentum broadening, employing $\langle k_T^2 \rangle$ and fragmentation in exclusive $Q \overline Q$ pair...
Open heavy-flavour mesons are a unique tool to investigate the properties of the Quark-Gluon Plasma (QGP) formed in heavy-ion collisions at high energy. Given their large masses, heavy quarks are produced in the initial stages of the collisions and thus witness the whole system evolution, losing energy interacting with the medium constituents. The measurement of the nuclear modification factor...
Heavy quarks are produced by hard scatterings at early times and experience almost the entire history of the collision evolution in relativistic heavy ion collisions. Their azimuthal anisotropy $v_{2}$ is a very useful tool for the study of the properties of the quark-gluon plasma (QGP). Recent studies with transport models suggest that the majority of the light quark $v_{2}$ at RHIC energies...
Heavy-quarks are sensitive probes for investigating the properties of the high- density medium formed in heavy-ion collisions. Their investigation in proton- proton (pp) collisions at the LHC, besides furnishing the necessary baseline for measurements in nucleus–nucleus collisions, provides precise tests for perturba- tive QCD (pQCD) calculations based on the factorization approach down to...
The measurement of D-meson production in jets can provide important insights into the interactions of heavy-flavour quarks with the quark-gluon plasma created in heavy ion collisions. In particular, the role of gluon splitting processes in the production of heavy flavour, which is fundamental for a complete understanding of the quenching mechanisms for both light and heavy quarks, can be...
Heavy quarks serve as ideal probes of the QGP properties produced in energetic nuclear collisions, and provide a unique opportunity to study the mass effects on parton energy loss. We develop a multi-stage approach [1,2] for heavy quark evolution inside the QGP, in which heavy quarks first undergo a rare-scattering multiple-emission evolution at momenta large compared to their mass (sensitive...
Recent progress in open-heavy-flavor measurements and future experimental upgrades are bringing heavy-flavor physics into the precision era, allowing for strong quantitative constraints on the transport properties of heavy quarks in the quark-gluon plasma. On the theory side, it will be imperative to understand the impact of model uncertainty regarding the extraction of heavy-quark transport...
Charm and beauty quarks are expected to form on a shorter time scale with respect to the strongly interacting matter, Quark-Gluon Plasma (QGP), produced in high-energy heavy-ion collisions. Therefore, witnessing the full evolution of the collision, they are effective probes to study the mechanisms of parton energy loss and hadronisation in the hot and dense medium, giving insight on the QGP...
Heavy flavor (HF) quarks (charm, bottom) are important probes of the medium produced in relativistic heavy-ion collisions because they are formed in the early stage and propagate throughout the lifetime of the system. HF-meson spectra and azimuthal anisotropy ($v_{2}$) measurements have been reported by experiments at RHIC and the LHC, and they suggest strong interactions of HF quarks with the...
The study of quarkonium in proton-nucleus collisions is an important tool to investigate how cold nuclear matter effects can influence the J/ψ, the ψ(2S) or the Υ production. Mechanisms as the modification of the parton distribution functions in nuclei, the presence of a color glass condensate or the coherent energy loss of the QQ ̄ pair in the medium have been shown to be the relevant...
Two-particle correlations using high-pT particles allow jet-like measurements at low Q2 where jet reconstruction is challenging. Therefore, such correlations provide critical input to our understanding of how partons interact in a colored medium. PHENIX has measured 0-hadron correlations in multiple collisions systems. The away-side widths in p+Au collisions are broader than those in p+p...
Gauge boson tagged jet production has long be regarded as a "golden channel" to study the jet quenching effect. Recently, the back-to-back azimuthal alignment $\Delta\phi_{jZ}$, $p_T$ asymmetry $x_{jZ}$ distribution and its mean value, as well as the average number of jet partners per Z boson $R_{jZ}$ of Z associated jet production have been reported in both pp and Pb-Pb collisions by...
PHENIX has performed measurements of light hadrons (0, , and other hadrons with masses up to ~1GeV) in a broad set of projectile-target combinations including p+Au, d+Au, 3He+Au, Cu+Cu, Cu+Au, Au+Au, and U+U. This rich collection of data sets allows for detailed studies of parton energy loss in large systems, exploring various scaling behaviors from RHIC to LHC. We also explore the...
The measurement of jets recoiling from a trigger hadron in heavy-ion collisions can be used to understand the properties of the Quark Gluon Plasma. Jet-medium interactions cause jets to lose energy in the medium, and may modify the jet structure. Jet deflection towards large angles may also occur - multiple soft scatterings in the medium broadens the overall azimuthal correlation, while...
The comparison of jets measured in heavy-ion collisions with jets measured in pp collisions is a rich source of information on jet-medium interactions. These medium-induced modifications can be prominent at low $p_{\rm T}$, where traditional jet reconstruction tools are difficult to use. Measurements of di-hadron correlations provide an alternative means to study jets in this $p_{\rm T}$...
Measurements of quarkonium production are an important tool to study the properties of the Quark-Gluon Plasma (QGP) formed in relativistic heavy-ion collisions. Quarkonium suppression due to the color-screening effect was proposed as a direct evidence of the QGP formation. However, other effects, such as cold nuclear matter effects and regeneration, add additional complications to the...
Quarkonium production is an excellent probe to investigate the properties of the hot and dense medium, which can be created in heavy-ion collisions. The production and hadronisation of heavy quarks are well separated in the space-time evolution of a collision and provide a wealth of information of the underlying QCD dynamics from the dense to the eventually diluting system.
We report on the...
Heavy quarkonia can be used as probes of the 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 screening of the color attraction between quark and antiquark. In this sense, quarkonia can be thought of as thermometers for the QGP. But extracting the melting temperature from...
We present new results on quarkonia production in proton-lead
collisions, using the data collected in 2016 at 8.16 TeV nucleon-nucleon
center-of-mass energy, in the unique forward region (pseudorapidity
between 2 and 5) covered by the LHCb detector. Both forward and backward
rapidities are covered thanks to the possibility of beam reversal.
Measurements include J/psi and psi', where the prompt...
The understanding of charmonium production in PbPb collisions requires the inclusion of many phenomena such as dissociation in the QGP, partonic energy loss, statistical recombination, on top of cold nuclear matter effects (modifications of nPDFs, initial-state energy loss, nuclear break-up). Final results on prompt J/$\psi$ and $\psi(2S)$ production, based on the pp and PbPb data collected at...
The suppression of Upsilon-mesons in the hot quark-gluon medium (QGP) versus reduced feed-down is investigated in heavy-ion collisions at energies reached at RHIC and at LHC. Our centrality- and p_T-dependent model encompasses screening, collisional damping and gluodissociation in the QGP. For Y(1S) it is in agreement with both STAR and CMS data provided the relativistic Doppler effect and the...
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...
The hadroproduction of heavy-flavoured mesons has recently attracted a growing interest e.g. within the groups involved in global analysis of proton/nuclear parton distribution functions (PDFs), saturation physics, and physics of cosmic rays. In particular, the D- and B-meson measurements of LHCb at forward direction are sensitive to gluon dynamics at small x and are one of the few...
The framework to compute the cross sections for the production of
particles with high mass and/or large transverse momentum in double- (DPS),
triple- (TPS), and in general n-parton scatterings, from the corresponding
single-parton (sigma_SPS) values in high-energy proton and nucleus will be
reviewed. The basic parameter of the factorized n-parton scattering ansatz
is an effective cross section...
A rich set of open heavy flavour states is observed by LHCb in pPb
collisions data collected at 5 and 8.16 TeV nucleon-nucleon
center-of-mass energy. Results include the new measurements of
production of beauty hadrons in pA collisions through cleanly
reconstructed exclusive decays. Open charm states include the Lambda_c
baryon, that was also observed in pA collisions for the first time by LHCb.
The heavy-flavor particles are produced in the earlier stage in heavy-ion collision and experience the full evolution of the QGP medium. The measurement of D mesons could provide us important inputs for flavor and charge dependent transport properties. On the other hand, with abundant strange quarks presented in heavy-ion collision, the $D_{S}^{+}$ production is expected to be enhanced...
LHCb has the unique capability to study collisions of the LHC beams on
fixed targets. Internal gas targets of helium, neon and argon have been
used so far. First final results and prospects on open and hidden charm
productions will be presented, which can provide crucial constraints on
cold nuclear matter effects and nPDF at large x. These measurements,
together with production of antiprotons...
NA61/SHINE (SPS Heavy Ion and Neutrino Experiment) is a fixed-target experiment operating at the CERN SPS accelerator. The main goal of the Collaboration is to study the properties of the phase transition between confined matter and quark-gluon plasma by performing a two-dimensional scan of the phase diagram of strongly interacting matter. Within this program, collisions of different systems...
Dilepton spectra are a classic probe to study ultra-relativistic heavy ion collisions. At RHIC energies, the dimuon continuum is dominated by correlated pairs from charm and bottom semi-leptonic decays and the Drell-Yan process. No Drell-Yan measurement had been made at sqrt(sNN)= 200 GeV to date. A precise measurement of the Drell-Yan cross-section can provide constraints to PDFs. The dimuon...
Charm quarks are a powerful probe of the Quark-Gluon Plasma (QGP) created in high-energy heavy-ion collisions. They are produced in hard scattering processes on a timescale shorter than the QGP formation time and experience the whole system evolution. There have been extensive researches regarding the production of charm mesons, such as ${\rm D}^0$, ${\rm D}^+$D+, ${\rm D}^{*+}$, in heavy-ion...
Because of their large mass, charm quarks are suggested to be an important tool for studying the properties of the Quark Gluon Plasma (QGP) produced in heavy-ion collisions. Recently, measurements at RHIC and LHC have indicated strong energy loss and large elliptic flow for open charm hadrons, similar in magnitude to those of light hadrons. The observed enhancements of $\Lambda_{c}^{\pm}$ and...
Due to their large mass, the interactions of heavy quarks with the quark-gluon plasma (QGP) may be different from those of light quarks. The lightest charm baryon is the $\Lambda_C^{+}$, composed of a charm quark and two light quarks. Measurements of $\Lambda_C^{+}$ production in both pp and PbPb collisions can provide important inputs to the understanding of heavy quark transport in the QGP...
The use of the lead LHC beam in the fixed-target mode allows one to study heavy-flavour production in a new energy domain, half way between SPS and RHIC. We will report on the opportunities for quarkonium and open charm/beauty production in Pb$A$ collisions including the prospects to study the relative suppression of $\Upsilon(nS)$ and new charmonium observables such as the $\chi_c$ and...
