J/psi production in p-A and A-A collisions at fixed target experiments

Charmonia suppression is one of the main signatures for the formation of a deconfined medium. However, also nuclear effects, not related to the production of a hot medium, can affect the J/psi yield. The determination, from the study of p-A collisions, of the J/psi behaviour in nuclear matter is, therefore, extremely important to correctly quantify the amount of charmonia suppression induced by the deconfined medium. In this paper the new NA60 results collected at 158 GeV incident energy, i.e. under the same kinematical conditions as the In-In (NA60) and Pb-Pb (NA50) data, are presented and compared with p-A measurements from other fixed target experiments. Results on A-A collisions are also reviewed taking into account the new available information on the influence of cold nuclear matter on the J/psi production yield. Finally, results on the J/psi polarization are shown for p-A and A-A collisions.Comment: 8 pages, 8 figures - To appear in the conference proceedings for Quark Matter 2009, March 30 - April 4, Knoxville, Tennesse

J/Psi and Psi(2S) production in Pb-Pb collisions with the ALICE Muon Spectrometer at the LHC

Charmonium states are considered important signatures of the strongly interacting medium created in heavy-ion collisions. In the ALICE experiment, these probes can be investigated in the mu^+mu^- decay channel, in the forward rapidity region (2.5<y<4) down to zero transverse momentum. Results on charmonia production in Pb-Pb collisions at sqrt(s_NN)=2.76 TeV are presented. The centrality and transverse momentum dependence of the inclusive J/Psi nuclear modification factor are shown and compared with theoretical models. Finally, first ALICE results on the Psi(2S) production in Pb-Pb collisions are also discussed.Comment: 4 pages, 4 figures, contribution to the proceedings of the Quark Matter 2012 International Conference, Washington D.C., August 13-18, 201

Prospects for open heavy-flavour and quarkonium measurements with NA60+

The high-intensity beams provided by the CERN SPS in a large range of energies offer a unique opportunity to investigate the region of the QCD phase diagram at high baryochemical potential. The NA60+ experiment, proposed for taking data with heavy-ion collisions at the SPS in the next years, is in an ideal position to provide new insights into the QCD phase diagram, measuring rare probes via a Pb-Pb and p-A beam-energy scan, in the collisions energy interval $\sqrt{s_{NN}}$= 6-17 GeV. NA60+ plans to measure the production of hidden and open charm hadrons and prospects on these measurements will be discussed. Open charm hadrons will be measured from their decays into charged hadrons, reconstructed from the tracks in the silicon detectors of the vertex telescope. This will enable high-precision measurements of the yield of D$^{0}$, D$^{+}$, and D$^{+}_{s}$ mesons, and of $\Lambda_{c}^{+}$ baryons, thus allowing us to constrain the transport properties of the QGP and the charm-quark hadronisation. Charmonium states, J/$\psi$ and $\psi$(2S), will be measured through dimuon decays reconstructed with the muon spectrometer. Hence, by measuring the charmonium yield in p-A and Pb-Pb collisions at different collision energies, NA60+ will have a unique opportunity to study the threshold energy for the onset of deconfinement.Comment: 6 pages, 5 figures, contribution to the proceedings of the 11th International Conference on Hard and Electromagnetic Probes of High-Energy Nuclear Collisions (Hard Probes 2023), Aschaffenburg (Germany), March 26-31, 2023. Submitted to Po

Inclusive Psi(2S) production in p-Pb collisions with ALICE

The ALICE Collaboration has studied the inclusive $\psi(\rm 2S)$ production in p-Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV at the CERN LHC. Measurements are performed, in the $\mu^{+}\mu^{-}$ decay channel, in a forward (2.03$<y_{\rm cms}<$3.53) and in a backward (-4.46$<y_{\rm cms}<$-2.96) centre of mass rapidity ranges, as a function of transverse momentum or event activity. The $\psi(\rm 2S)$ production is compared to the $\rm J/\psi$ one through the double ratio $[\sigma_{\psi(\rm 2S)}/\sigma_{\rm J/\psi}]_{\rm pPb}/[\sigma_{\psi(\rm 2S)}/\sigma_{\rm J/\psi}]_{\rm pp}$ between the cross sections evaluated in p-Pb and pp collisions and by calculating the $\rm J/\psi$ and $\psi(\rm 2S)$ nuclear modification factors. Results indicate that the $\psi(\rm 2S)$ production is suppressed with respect to pp and, in particular in the backward rapidity region, the suppression is stronger than the $\rm J/\psi$ one. This unexpected difference between the $\rm J/\psi$ and $\psi(\rm 2S)$ behaviour, not accounted for by theoretical models based on nuclear parton shadowing and coherent energy loss mechanisms, indicates the presence of sizeable final state effects on the $\psi(\rm 2S)$ production.Comment: 4 pages, 6 figures, Proceedings of the "Quark Matter 2014 Conference", XXIV International Conference on Ultrarelativistic Nucleus-Nucleus Collisions, Darmstadt, May 19-24 201

Patients with Alzheimer's disease dementia show partially preserved parietal 'hubs' modeled from resting-state alpha electroencephalographic rhythms

IntroductionGraph theory models a network by its nodes (the fundamental unit by which graphs are formed) and connections. 'Degree' hubs reflect node centrality (the connection rate), while 'connector' hubs are those linked to several clusters of nodes (mainly long-range connections). MethodsHere, we compared hubs modeled from measures of interdependencies of between-electrode resting-state eyes-closed electroencephalography (rsEEG) rhythms in normal elderly (Nold) and Alzheimer's disease dementia (ADD) participants. At least 5 min of rsEEG was recorded and analyzed. As ADD is considered a 'network disease' and is typically associated with abnormal rsEEG delta (<4 Hz) and alpha rhythms (8-12 Hz) over associative posterior areas, we tested the hypothesis of abnormal posterior hubs from measures of interdependencies of rsEEG rhythms from delta to gamma bands (2-40 Hz) using eLORETA bivariate and multivariate-directional techniques in ADD participants versus Nold participants. Three different definitions of 'connector' hub were used. ResultsConvergent results showed that in both the Nold and ADD groups there were significant parietal 'degree' and 'connector' hubs derived from alpha rhythms. These hubs had a prominent outward 'directionality' in the two groups, but that 'directionality' was lower in ADD participants than in Nold participants. DiscussionIn conclusion, independent methodologies and hub definitions suggest that ADD patients may be characterized by low outward 'directionality' of partially preserved parietal 'degree' and 'connector' hubs derived from rsEEG alpha rhythms

Patients with Alzheimer’s disease dementia show partially preserved parietal ‘hubs’ modeled from resting-state alpha electroencephalographic rhythms

Introduction: Graph theory models a network by its nodes (the fundamental unit by which graphs are formed) and connections. ‘Degree’ hubs reflect node centrality (the connection rate), while ‘connector’ hubs are those linked to several clusters of nodes (mainly long-range connections). Methods: Here, we compared hubs modeled from measures of interdependencies of between-electrode resting-state eyes-closed electroencephalography (rsEEG) rhythms in normal elderly (Nold) and Alzheimer’s disease dementia (ADD) participants. At least 5 min of rsEEG was recorded and analyzed. As ADD is considered a ‘network disease’ and is typically associated with abnormal rsEEG delta (<4 Hz) and alpha rhythms (8–12 Hz) over associative posterior areas, we tested the hypothesis of abnormal posterior hubs from measures of interdependencies of rsEEG rhythms from delta to gamma bands (2–40 Hz) using eLORETA bivariate and multivariate-directional techniques in ADD participants versus Nold participants. Three different definitions of ‘connector’ hub were used. Results: Convergent results showed that in both the Nold and ADD groups there were significant parietal ‘degree’ and ‘connector’ hubs derived from alpha rhythms. These hubs had a prominent outward ‘directionality’ in the two groups, but that ‘directionality’ was lower in ADD participants than in Nold participants. Discussion: In conclusion, independent methodologies and hub definitions suggest that ADD patients may be characterized by low outward ‘directionality’ of partially preserved parietal ‘degree’ and ‘connector’ hubs derived from rsEEG alpha rhythms

Final results of the tests on the resistive plate chambers for the ALICE muon arm

Abstract The trigger for the ALICE muon spectrometer will be issued by single-gap, low resistivity bakelite resistive plate chambers (RPCs). The trigger system consists of four 5.5 × 6.5 m 2 RPC planes arranged in two stations, for a total of 72 detectors. One hundred and sixteen detectors have been assembled and tested in Torino. The tests have been performed with the streamer mixture developed for heavy ion data-taking. The tests include: the detection of gas leaks and parasitic currents; the measurement of the efficiency with cosmic rays, with particular regard to the uniformity of the efficiency throughout the whole active surface, with a granularity of about 2 × 2 cm 2 ; the measurement of the dark current and of the mean and localised noise rate. All the RPCs produced have been characterised. Among them, the detectors to be finally installed in ALICE and some spare have been selected; 17% of all the produced detectors have been discarded. A short description of the test set-up is given. The results of the tests are presented, with particular regard to the performance of the selected detectors