Azimuthal anisotropy of charged jet production in root s(NN)=2.76 TeV Pb-Pb collisions

We present measurements of the azimuthal dependence of charged jet production in central and semi-central root s(NN) = 2.76 TeV Pb-Pb collisions with respect to the second harmonic event plane, quantified as nu(ch)(2) (jet). Jet finding is performed employing the anti-k(T) algorithm with a resolution parameter R = 0.2 using charged tracks from the ALICE tracking system. The contribution of the azimuthal anisotropy of the underlying event is taken into account event-by-event. The remaining (statistical) region-to-region fluctuations are removed on an ensemble basis by unfolding the jet spectra for different event plane orientations independently. Significant non-zero nu(ch)(2) (jet) is observed in semi-central collisions (30-50% centrality) for 20 <p(T)(ch) (jet) <90 GeV/c. The azimuthal dependence of the charged jet production is similar to the dependence observed for jets comprising both charged and neutral fragments, and compatible with measurements of the nu(2) of single charged particles at high p(T). Good agreement between the data and predictions from JEWEL, an event generator simulating parton shower evolution in the presence of a dense QCD medium, is found in semi-central collisions. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Peer reviewe

Production of He-4 and (4) in Pb-Pb collisions at root(NN)-N-S=2.76 TeV at the LHC

Results on the production of He-4 and (4) nuclei in Pb-Pb collisions at root(NN)-N-S = 2.76 TeV in the rapidity range vertical bar y vertical bar <1, using the ALICE detector, are presented in this paper. The rapidity densities corresponding to 0-10% central events are found to be dN/dy4(He) = (0.8 +/- 0.4 (stat) +/- 0.3 (syst)) x 10(-6) and dN/dy4 = (1.1 +/- 0.4 (stat) +/- 0.2 (syst)) x 10(-6), respectively. This is in agreement with the statistical thermal model expectation assuming the same chemical freeze-out temperature (T-chem = 156 MeV) as for light hadrons. The measured ratio of (4)/He-4 is 1.4 +/- 0.8 (stat) +/- 0.5 (syst). (C) 2018 Published by Elsevier B.V.Peer reviewe

Forward-central two-particle correlations in p-Pb collisions at root s(NN)=5.02 TeV

Two-particle angular correlations between trigger particles in the forward pseudorapidity range (2.5 2GeV/c. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B. V.Peer reviewe

Event-shape engineering for inclusive spectra and elliptic flow in Pb-Pb collisions at root(NN)-N-S=2.76 TeV

Peer reviewe

Pseudorapidity and transverse-momentum distributions of charged particles in proton-proton collisions at root s=13 TeV

The pseudorapidity (eta) and transverse-momentum (p(T)) distributions of charged particles produced in proton-proton collisions are measured at the centre-of-mass energy root s = 13 TeV. The pseudorapidity distribution in vertical bar eta vertical bar <1.8 is reported for inelastic events and for events with at least one charged particle in vertical bar eta vertical bar <1. The pseudorapidity density of charged particles produced in the pseudorapidity region vertical bar eta vertical bar <0.5 is 5.31 +/- 0.18 and 6.46 +/- 0.19 for the two event classes, respectively. The transverse-momentum distribution of charged particles is measured in the range 0.15 <p(T) <20 GeV/c and vertical bar eta vertical bar <0.8 for events with at least one charged particle in vertical bar eta vertical bar <1. The evolution of the transverse momentum spectra of charged particles is also investigated as a function of event multiplicity. The results are compared with calculations from PYTHIA and EPOS Monte Carlo generators. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Peer reviewe

Elliptic flow of muons from heavy-flavour hadron decays at forward rapidity in Pb-Pb collisions at root s(NN)=2.76TeV

The elliptic flow, v(2), of muons from heavy-flavour hadron decays at forward rapidity (2.5 <y <4) is measured in Pb-Pb collisions at root s(NN)= 2.76TeVwith 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 v(2) of muons from heavy-flavour hadron decays on the collision centrality, in the range 0-40%, and on transverse momentum, p(T), is studied in the interval 3 <p(T)<10 GeV/c. A positive v(2) is observed with the scalar product and two-particle Q cumulants in semi-central collisions (10-20% and 20-40% centrality classes) for the p(T) interval from 3 to about 5GeV/c with a significance larger than 3 sigma, based on the combination of statistical and systematic uncertainties. The v(2) magnitude tends to decrease towards more central collisions and with increasing pT. It becomes compatible with zero in the interval 6 <p(T)<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. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B.V.Peer reviewe

Centrality evolution of the charged-particle pseudorapidity density over a broad pseudorapidity range in Pb-Pb collisions at root s(NN)=2.76TeV

Peer reviewe

Measurement of charged jet production cross sections and nuclear modification in p-Pb collisions at root s(NN)=5.02 TeV

Charged jet production cross sections in p-Pb collisions at root s(NN) = 5.02 TeV measured with the ALICE detector at the LHC are presented. Using the anti-k(T) algorithm, jets have been reconstructed in the central rapidity region from charged particles with resolution parameters R = 0.2 and R = 0.4. The reconstructed jets have been corrected for detector effects and the underlying event background. To calculate the nuclear modification factor, R-pPb, of charged jets in p-Pb collisions, a pp reference was constructed by scaling previously measured charged jet spectra at root s = 7 TeV. In the transverse momentum range 20Peer reviewe

D^{∗+}-meson production in proton-proton and proton-lead collisions in ALICE

D^{*+} meson results in proton-proton collisions at \sqrt{s}=13 TeV and proton-lead collisions at \sqrt{s_{NN}}=5.02 TeV at the Large Hadron Collider collected with the ALICE detector are presented. Heavy quarks, such as the charm quark that is a constituent of the D^{*+} meson, are effective probes for the study of the properties of the Quark-Gluon Plasma formed in high energy Pb--Pb collisions, as heavy quarks are mainly produced in hard scattering processes in the initial stages of the collision. In p--Pb collisions the production of heavy flavour quarks can be influenced by Cold Nuclear Matter (CNM) effects. The nuclear modification, R_{AA} (R_{\rm pPb}) measures the plasma (CNM) effects in Pb--Pb (p--Pb) collisions on the transverse momentum(pt)-distribution of the final state particles compared to a particles distribution from minimum bias pp collisions. The comparison of heavy flavour production in proton-Pb and Pb--Pb collisions via the nuclear modification factor allows to distinguish between CNM effects and hot-nuclear matter effects present in Pb--Pb collisions. Measurements of the heavy flavour hadron cross-section in proton-proton collisions allows to test pertubative Quantum Chromo Dynamic calculations and forms a reference measurement for the R_{\rm{AA}} or R_{\rm pPb}. Ratio measurements of the cross-section in pp collisions between different collision energies make it possible to probe the gluonic properties of the theory with measurements at low D-meson pt. The proton-proton results presented in this thesis are within uncertainty consistent with FONLL predictions, though consistently above the central value. The presented preliminary results of the ratio of the cross-section at 13 TeV with respect to 5 TeV are fully consistent with predictions, and the uncertainty on the measurement and theory are similar. An increase in statistics could significantly improve these results and might make it possible to separate fluctuations from actual differences especially at low transverse momenta as well as further constrain the FONLL predictions. The presented proton-lead results are consistent with the results in proton-proton collisions. The nuclear modification factor for the average of D-mesons shows a flat trend for transverse momenta above 3GeV/c. These results are in agreement with various models that include CNM effects in the full pt range, disfavouring a calculation based on incoherent multiple scatterings at low transverse momenta. Models including also some form of Quark-Gluon Plasma show a different trend with respect to pt, but cannot fully be excluded based on the current measurements. Measurements done in multiplicity sets in proton-lead collisions show hints of a non-flat shape. These results also show a non-unity centrality ratio at 3sigma precision of which the shape is seen at all centralities, hinting towards some form of flow in p--Pb. Measurements of heavy flavour decay electrons find a non-zero $v_2$, possibly due to fluctuations in the initial state geometry, but it can also be explained by a very small QGP in proton-lead collisions. The ongoing upgrades on the ITS will allow the ALICE detector to do more precise measurements at lower pt. The extra precision will also allow us to correct for any B-decay D^{*+} mesons via measurement

Immunogenicity of the mRNA-1273 COVID-19 vaccine in adult patients with inborn errors of immunity

BACKGROUND: Patients with inborn errors of immunity (IEI) are at increased risk of severe coronavirus disease-2019 (COVID-19). Effective vaccination against COVID-19 is therefore of great importance in this group, but little is known about the immunogenicity of COVID-19 vaccines in these patients. OBJECTIVES: We studied humoral and cellular immune responses after mRNA-1273 COVID-19 vaccination in adult IEI patients. METHODS: In a prospective, controlled, multicenter study 505 IEI patients (common variable immunodeficiency (CVID), isolated or undefined antibody deficiencies, X-linked agammaglobulinemia (XLA), combined immunodeficiency (CID), phagocyte defects) and 192 controls were included. All participants received two doses of the mRNA-1273 COVID-19 vaccine. Levels of SARS-CoV-2-specific binding antibodies, neutralizing antibodies, and T-cell responses were assessed at baseline, 28 days after first and 28 days after second vaccination. RESULTS: Seroconversion rates in patients with clinically mild antibody deficiencies and phagocyte defects were similar to healthy controls, but seroconversion rates in patients with more severe IEI, like CVID and CID, were lower. Binding antibody titers correlated well to the presence of neutralizing antibodies. T-cell responses were comparable to controls in all IEI cohorts, with the exception of CVID patients. The presence of non-infectious complications and the use of immunosuppressive drugs in CVID patients were negatively correlated with the antibody response. CONCLUSION: COVID-19 vaccination with mRNA-1273 was immunogenic in mild antibody deficiencies and phagocyte defects and in most patients with CID and CVID. Lowest response was detected in XLA and in CVID patients with non-infectious complications. The assessment of longevity of immune responses in these vulnerable patient groups will guide decision-making for additional vaccinations