Forward Rapidity In Pb Research Articles

Measurements of inclusive J/ψ production at midrapidity and forward rapidity in Pb–Pb collisions at [formula omitted] = 5.02 TeV

The measurements of the inclusive J/ψ yield at midrapidity (|y|<0.9) and forward rapidity (2.5 <y< 4) in Pb–Pb collisions at sNN=5.02 TeV with the ALICE detector at the LHC are reported. The inclusive J/ψ production yields and nuclear modification factors, RAA, are measured as a function of the collision centrality, J/ψ transverse momentum (pT), and rapidity. The J/ψ average transverse momentum and squared transverse momentum (〈pT〉 and 〈pT2〉) are evaluated as a function of the centrality at midrapidity. Compared to the previous ALICE publications, here the entire Pb–Pb collisions dataset collected during the LHC Run 2 is used, which improves the precision of the measurements and extends the pT coverage. The pT-integrated RAA shows a hint of an increasing trend towards unity from semicentral to central collisions at midrapidity, while it is flat at forward rapidity. The pT-differential RAA shows a strong suppression at high pT with less suppression at low pT where it reaches a larger value at midrapidity compared to forward rapidity. The ratio of the pT-integrated yields of J/ψ to those of D0 mesons is reported for the first time for the central and semicentral event classes at midrapidity. Model calculations implementing charmonium production via the coalescence of charm quarks and antiquarks during the fireball evolution (transport models) or in a statistical approach with thermal weights are in good agreement with the data at low pT. At higher pT, the data are well described by transport models and a model based on energy loss in the strongly-interacting medium produced in nuclear collisions at the LHC.

Recent charmonium measurements in Pb–Pb collisions with ALICE

Charmonia have long been recognized as a valuable probe of the nuclear matter in extreme conditions, the strongly interacting medium created in heavy-ion collisions known as quark-gluon plasma (QGP). At LHC energies, the (re-)generation process due to the abundantly produced charm quarks, was found to considerably affect measured charmonium observables. Comprehensive production measurements of charmonia, including both ground and excited states, are crucial to discriminate among different (re-)generation scenarios assumed in theoretical calculations. In addition, the spin-alignment of charmonia can be affected by the strong magnetic field and the large angular momentum of the medium in non-central heavy-ion collisions. Finally, the non-prompt charmonium, grants a direct insight into the nuclear modification factor of beauty hadrons, which is expected to be sensitive to the energy loss experienced by the ancestor beauty quarks inside the QGP. In this contribution, newly published results of inclusive, prompt and non-prompt J/ψ production, obtained in Pb–Pb collisions at √SNN = 5.02 TeV, are presented. Recently published results of J/ψ polarization with respect to the event plane at forward rapidity in Pb–Pb collisions at √SNN = 5.02 TeV are also discussed. Results are compared to available model calculations.

ϒ production and nuclear modification at forward rapidity in Pb–Pb collisions at [formula omitted

The production of ϒ mesons in Pb–Pb collisions at a centre-of-mass energy per nucleon pair sNN=5.02 TeV is measured with the muon spectrometer of the ALICE detector at the LHC. The yields as well as the nuclear modification factors are determined in the forward rapidity region 2.5<y<4.0, as a function of rapidity, transverse momentum and collision centrality. The results show that the production of the ϒ(1S) meson is suppressed by a factor of about three with respect to the production in proton–proton collisions. For the first time, a significant signal for the ϒ(2S) meson is observed at forward rapidity, indicating a suppression stronger by about a factor 2–3 with respect to the ground state. The measurements are compared with transport, hydrodynamic, comover and statistical hadronisation model calculations.

Studies of J/\u03c8 production at forward rapidity in Pb\u2013Pb collisions at sqrt{s_{mathrm{NN}}} = 5.02 TeV

The inclusive J/ψ production in Pb–Pb collisions at the center-of-mass energy per nucleon pair sqrt{s_{mathrm{NN}}} = 5.02 TeV, measured with the ALICE detector at the CERN LHC, is reported. The J/ψ meson is reconstructed via the dimuon decay channel at forward rapidity (2.5 < y < 4) down to zero transverse momentum. The suppression of the J/ψ yield in Pb–Pb collisions with respect to binary-scaled pp collisions is quantified by the nuclear modification factor (RAA). The RAA at sqrt{s_{mathrm{NN}}} = 5.02 TeV is presented and compared with previous measurements at sqrt{s_{mathrm{NN}}} = 2.76 TeV as a function of the centrality of the collision, and of the J/ψ transverse momentum and rapidity. The inclusive J/ψ RAA shows a suppression increasing toward higher transverse momentum, with a steeper dependence for central collisions. The modification of the J/ψ average transverse momentum and average squared transverse momentum is also studied. Comparisons with the results of models based on a transport equation and on statistical hadronization are carried out.

Charmonium production in Pb–Pb and p–Pb collisions at forward rapidity measured with ALICE

The ALICE collaboration has measured the inclusive charmonium production at forward rapidity in Pb–Pb and p–Pb collisions at sNN=5.02TeV and sNN=8.16TeV, respectively. In Pb–Pb collisions, the J/ψ and ψ(2S) nuclear modification factors (RAA), as well as the J/ψ elliptic flow (v2) and averaged squared transverse momentum (〈pT2〉), are presented. In p–Pb collisions, the J/ψ nuclear modification factor (RpPb) as a function of pt and rapidity is presented. In both systems, our measurements are compared to theoretical calculations and to the results at lower energies.

Measurements of the nuclear modification factor and elliptic flow of leptons from heavy-flavour hadron decays in Pb–Pb collisions at [formula omitted] and 5.02 TeV with ALICE

We present the ALICE results on the nuclear modification factor and elliptic flow of electrons and muons from open heavy-flavour hadron decays at mid-rapidity and forward rapidity in Pb–Pb collisions at sNN=2.76 and 5.02 TeV for different centrality intervals. The results are compared to model calculations that include interactions of heavy quarks with the medium.

Production of muons from heavy-flavour hadron decays at forward rapidity in Pb–Pb collisions at [formula omitted

The measurement of the production of single muons from heavy-flavour hadron decays at forward rapidity in Pb–Pb collisions at sNN=5.02 TeV collected in 2015 is presented as a function of transverse momentum (pT) and collision centrality. A strong suppression of the yield is observed at high pT in the most central collisions compared to the binary-scaled expectation from pp collisions at the same energy. The pT-integrated nuclear modification factor (RAA) as function of the number of participating nucleons indicates an increase of the suppression from peripheral to central collisions. Comparisons with the results for Pb–Pb collisions at sNN=2.76 TeV and with transport model predictions are shown. A similar suppression is measured at both sNN=2.76 TeV and 5.02 TeV. The results available from pT=7 GeV/c up to pT=20 GeV/c, will provide new constraints on transport model ingredients and new insights on the understanding of the evolution of the hot and dense matter formed in ultra-relativistic heavy-ion collisions.

Measurements of heavy-flavour nuclear modification factor and elliptic flow in Pb–Pb collisions at [formula omitted] with ALICE

Heavy quarks, i.e. charm and beauty (bottom), are sensitive probes of the medium produced in high-energy heavy-ion collisions. They are produced in the early stage of the collisions and are expected to experience the whole collision evolution interacting with the medium constituents via both elastic and inelastic processes. The nuclear modification factor (RAA) and the elliptic flow (v2) are two of the main experimental observables that allow us to investigate the interaction strength of heavy quarks with the medium. The ALICE collaboration measured the production and elliptic flow of open heavy-flavour hadrons via their hadronic and semi-leptonic decays to electrons at mid-rapidity and to muons at forward rapidity in Pb–Pb collisions. Recent results will be discussed, and model calculations including the interaction of heavy quarks with the hot, dense, and deconfined medium will be confronted with the data.

Elliptic flow of muons from heavy-flavour hadron decays at forward rapidity in Pb–Pb collisions at [formula omitted

The elliptic flow, v2, of muons from heavy-flavour hadron decays at forward rapidity (2.5<y<4) is measured in Pb–Pb collisions at sNN=2.76 TeV with the ALICE detector at the LHC. The scalar product, two- and four-particle Q cumulants and Lee–Yang zeros methods are used. The dependence of the v2 of muons from heavy-flavour hadron decays on the collision centrality, in the range 0–40%, and on transverse momentum, pT, is studied in the interval 3<pT<10 GeV/c. A positive v2 is observed with the scalar product and two-particle Q cumulants in semi-central collisions (10–20% and 20–40% centrality classes) for the pT interval from 3 to about 5 GeV/c with a significance larger than 3σ, based on the combination of statistical and systematic uncertainties. The v2 magnitude tends to decrease towards more central collisions and with increasing pT. It becomes compatible with zero in the interval 6<pT<10 GeV/c. The results are compared to models describing the interaction of heavy quarks and open heavy-flavour hadrons with the high-density medium formed in high-energy heavy-ion collisions.

Low-mass dilepton production with ALICE at the LHC

The production of low-mass dileptons, including those from ρ, ω and ϕ light vector meson decays, provides key information on the hot and dense state of strongly interacting matter produced in high-energy heavy-ion collisions. In particular, strangeness production can be studied through ϕ meson measurements, while the detailed description of the full dilepton mass spectra down to the kinematic threshold can be used to reveal in-medium modifications of hadron properties and the thermal emission arising from the medium. Measurements in pp and p–A, respectively, provide a reference for the observations in heavy-ion collisions and give insight on soft particle production in cold nuclear matter. Dilepton production is studied with the ALICE apparatus at the LHC both at central (|y|<0.9) and forward (2.5<y<4) rapidity, respectively in the dielectron and dimuon channel. In this contribution, we present recent results on low-mass dimuon production at forward rapidity in Pb–Pb and p–Pb collisions.

Nuclear modification factor and elliptic flow of muons from heavy-flavour hadron decays in Pb–Pb collisions at sNN=2.76 TeV

Results from ALICE on the measurement of the nuclear modification factor, R AA , and elliptic flow, v 2 , of muons from heavy-flavour hadron decays at forward rapidity in Pb–Pb collisions at s NN = 2.76 TeV are reported. A strong suppression of the production of muons from heavy-flavour hadron decays is observed at high transverse momentum, p T , in the most central collisions compared to the binary-scaled expectation from pp collisions at the same energy, while a positive elliptic flow is observed at intermediate p T in semi-central collisions. Comparisons with model predictions are presented.

Coherent photoproduction of J/ψ at forward rapidity in Pb–Pb collisions with the ALICE detector

We present the measurement of coherent photoproduction of J/ψ at forward rapidity in Pb–Pb collisions with the ALICE detector at the LHC.

J/ψ production at forward rapidity in Pb–Pb collisions at TeV, measured with the ALICE detector

In the ALICE experiment, at forward rapidity (2.5 < y < 4), the production of heavy quarkonium states is measured via their μ+μ− decay channels. We present the first measurement of inclusive J/ψ production, down to pT = 0, from Pb–Pb data collected at the LHC at TeV. Preliminary results on the nuclear modification factor (RAA) and the central to peripheral nuclear modification factor (RCP) show J/ψ suppression with no significant centrality dependence and an integrated .