We report on broadly based systematic investigations of the modeling components for open heavy-flavor diffusion and energy loss in strongly interacting matter in their application to heavy-flavor ...observables in high-energy heavy–ion collisions, conducted within an EMMI Rapid Reaction Task Force framework. Initial spectra including cold-nuclear-matter effects, a wide variety of space-time evolution models, heavy-flavor transport coefficients, and hadronization mechanisms are scrutinized in an effort to quantify pertinent uncertainties in the calculations of nuclear modification factors and elliptic flow of open heavy-flavor particles in nuclear collisions. We develop procedures for error assessments and criteria for common model components to improve quantitative estimates for the (low-momentum) heavy-flavor diffusion coefficient as a long-wavelength characteristic of QCD matter as a function of temperature, and for energy loss coefficients of high-momentum heavy-flavor particles.
The Future Circular Collider is a new proposed collider at CERN with centre-of-mass energies around 100 TeV in the pp mode. Ongoing studies aim at assessing its physics potential and technical ...feasibility. Here we focus on updates in physics opportunities accessible in pA and AA collisions not covered in previous Quark Matter contributions, including Quark-Gluon Plasma and gluon saturation studies, novel hard probes of QCD matter, and photon-induced collisions.
The unique physics opportunities accessible with nuclear collisions at the CERN Future Circular Collider (FCC) are summarized. Lead-lead (PbPb) and proton-lead (pPb) collisions at sNN=39 and 63 TeV ...respectively with Lint=33nb−1 and 8 pb−1 monthly integrated luminosities, will provide unprecedented experimental conditions to study quark-gluon matter at temperatures O(1 GeV). The following topics are succinctly discussed: (i) charm-quark densities thrice larger than at the LHC, leading to direct heavy-quark impact in the bulk QGP properties, (ii) quarkonia, including ϒ(1S), melting at temperatures up to five times above the QCD critical temperature, (iii) access to initial-state nuclear parton distributions (nPDF) at fractional momenta as low as x≈10−7, (iv) availability of about 5⋅105 top-quark pairs per run to study the high-x gluon nPDF and the energy loss properties of boosted colour-antennas, (v) study of possible Higgs boson suppression in the QGP, and (vi) high-luminosity γγ (ultraperipheral) collisions at c.m. energies up to 1 TeV.
At LHC energy, heavy quarks will be abundantly produced and the design of the ALICE detector will allow us to study their production using several channels. The expected heavy-quark in-medium energy ...loss in nucleus-nucleus collisions at the LHC is calculated within a model, that is compared to the available heavy-quark quenching measurements at RHIC. The nuclear modification factors and heavy-to-light ratios of charm and beauty mesons are considered. The capability of the ALICE experiment for addressing this phenomenology is discussed.
Charm mesons produced in nucleus-nucleus collisions are expected to be less attenuated (quenched) by the medium than hadrons containing only light quarks, since radiative energy loss of heavy quarks ...should be reduced by the ‘dead-cone’ effect. We start from a published energy-loss model to derive the quenching for D mesons at the LHC, introducing an approximation of the dead-cone effect and employing a Glauber-based description of the geometry of central Pb-Pb collisions to estimate the in-medium path lengths of c quarks. We show that the exclusive reconstruction of \({\rm D}^0\to{\rm K\pi}^ + \) decays in ALICE allows to measure the nuclear modification factor of the D mesons transverse momentum distribution and the D/charged hadrons ratio and, thus, to investigate the energy loss of c quarks.
The measurement of the heavy-flavour production cross sections in pp collisions at the LHC will allow to test perturbative QCD calculations in a new energy domain. Moreover, within the physics ...program of the ALICE experiment, it will provide the reference for the study of medium effects in Pb–Pb collisions, where heavy quarks are regarded as sensitive probes of parton–medium interaction dynamics. We present the status and first preliminary results of charm and beauty production measurements with the ALICE experiment, using hadronic D meson decays and semi-leptonic D and B meson decays, including the first cross section measurement of muons from heavy flavour decays at forward rapidity. We also describe the preliminary cross section measurement for
J
/
ψ
production, obtained using the di-electron decay channel at central rapidity and the di-muon decay channel at forward rapidity.
The ratio of nuclear modification factors of high-
p
T
heavy-flavored mesons to light-flavored hadrons (heavy-to-light ratio) is shown to be a sensitive tool to test medium-induced energy loss at ...RHIC and LHC energies. Heavy-to-light ratios of
D mesons at RHIC in the region
7
<
p
T
<
12
GeV
, and of
D and
B mesons at the LHC in the region
10
<
p
T
<
20
GeV
, are proposed for such a test. Finally, the different contributions to the nuclear modification factor for electrons at RHIC are analyzed. Preliminary PHENIX and STAR data are compatible with radiative energy loss provided the contribution of electrons from beauty decays is small compared to that from charm.
We study the nuclear modification factors RAA and RCP of the high transverse momentum (5<pt<60 GeV/c) distribution of muons in Pb–Pb collisions at LHC energies. We consider two pseudo-rapidity ranges ...covered by the LHC experiments: |η|<2.5 and 2.5<η<4. Muons from semi-leptonic decays of heavy quarks (c and b) and from leptonic decays of weak gauge bosons (W and Z) are the main contributions to the muon pt distribution above a few GeV/c. We compute the heavy quark contributions using available pQCD-based programs. We include the nuclear shadowing modification of the parton distribution functions and the in-medium radiative energy loss for heavy quarks, using the mass-dependent BDMPS quenching weights. Muons from W and Z leptonic decays, that dominate the yield at high pt, can be used as a medium-blind reference to observe the medium-induced suppression of beauty quarks.
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