Thalassaemia (part 2): Management

The management of thalassaemia with a severe phenotype includes blood transfusion, iron chelation, bone marrow transplantation, prenatal diagnosis and national programmes to co-ordinate these in countries with a high prevalence. If blood transfusion and iron chelation therapy are not administered regularly, as was the case historically and as is still the case in many poorer regions, progressive deterioration occurs, viz. impaired growth and development, hepatosplenomegaly, bony abnormalities, cardiac failure, increased susceptibility to infections and premature mortality. Remarkable progress has been made in the past few decades, which has led to much-improved survival rates. Transfusion therapy has evolved to a hyper-transfusion regimen designed to maintain a physiological haemoglobin level and achieve a post-transfusion haemoglobin of 14 g/dL, which, as a matter of course, necessitated intensification of iron chelation. The development of effective oral iron chelators has led to improved compliance. Exploration of novel therapeutic approaches continues, with several agents under study. The prospect of gene therapy is particularly exciting as it has potential to provide cure on a large scale. Currently, regular blood transfusion and iron chelation therapy remain the cornerstone of management of thalassaemia major

Coherent photoproduction of rho(0) vector mesons in ultra-peripheral Pb-Pb collisions at root s(NN)=5.02 TeV

Cross sections for the coherent photoproduction of rho(0) vector mesons in ultra-peripheral Pb-Pb collisions at root s(NN) = 5.02 TeV are reported. The measurements, which rely on the pi(+)pi(-) decay channel, are presented in three regions of rapidity covering the range vertical bar y vertical bar <0.8. For each rapidity interval, cross sections are shown for different nuclear-breakup classes defined according to the presence of neutrons measured in the zero-degree calorimeters. The results are compared with predictions based on different models of nuclear shadowing. Finally, the observation of a coherently produced resonance-like structure with a mass around 1.7 GeV/c(2) and a width of about 140 MeV/c(2) is reported and compared with similar observations from other experiments.Peer reviewe

J/psi elliptic and triangular flow in Pb-Pb collisions at root s(NN)=5.02 TeV

The inclusive J/psi (v(2)) and triangular (v(3)) flow coefficients measured at forward rapidity (2.5 <y <4) and the v2 measured at midrapidity (vertical bar y vertical bar <0.9) in Pb-Pb collisions at root s(NN) = 5.02TeV using the ALICE detector at the LHC are reported. The entire Pb-Pb data sample collected during Run 2 is employed, amounting to an integrated luminosity of 750 mu b(-1) at forward rapidity and 93 mu b(-1) at midrapidity. The results are obtained using the scalar product method and are reported as a function of transverse momentum p(T) and collision centrality. At midrapidity, the J psi v(2) is in agreement with the forward rapidity measurement. The centrality averaged results indicate a positive J/psi v(3) with a significance of more than 5 sigma at forward rapidity in the p(T) range 2 <p(T) <5 GeV/c. The forward rapidity v(2), v(3), and v(3)/v(2) results at low and intermediate p(T) (p(T) <8 GeV/c) exhibit a mass hierarchy when compared to pions and D mesons, while converging into a species-independent curve at higher p(T). At low and intermediate p(T), the results could be interpreted in terms of a later thermalization of charm quarks compared to light quarks, while at high p(T), path-length dependent effects seem to dominate. The J/psi v(2) measurements are further compared to a microscopic transport model calculation. Using a simplified extension of the quark scaling approach involving both light and charm quark flow components, it is shown that the D-meson vn measurements can be described based on those for charged pions and J/flow.Peer reviewe

Elliptic and triangular flow of (anti)deuterons in Pb-Pb collisions root S-NN=5.02 TeV

The measurements of the (anti)deuteron elliptic flow (v(2)) and the first measurements of triangular flow (v(3)) in Pb-Pb collisions at a center-of-mass energy per nucleon-nucleon collision root S-NN = 5.02 TeV are presented. A mass ordering at low transverse momentum (p(T)) is observed when comparing these measurements with those of other identified hadrons, as expected from relativistic hydrodynamics. The measured (anti)deuteron v(2) lies between the predictions from the simple coalescence and blast-wave models, which provide a good description of the data only for more peripheral and for more central collisions, respectively. The mass number scaling, which is violated for v(2), is approximately valid for the (anti)deuterons v(3). The measured v(2) and v(3) are also compared with the predictions from a coalescence approach with phase-space distributions of nucleons generated by IEBE-VISHNU with AMPT initial conditions coupled with URQMD, and from a dynamical model based on relativistic hydrodynamics coupled to the hadronic afterburner SMASH. The model predictions are consistent with the data within the uncertainties in midcentral collisions, while a deviation is observed in the most central collisions.Peer reviewe

Measurement of isolated photon-hadron correlations in root S-NN=5.02 TeV pp and p-Pb collisions

This paper presents isolated photon-hadron correlations using pp and p-Pb data collected by the ALICE detector at the LHC. For photons with vertical bar eta vertical bar <0.67 and 12 <p(T) <40 GeV/c, the associated yield of charged particles in the range vertical bar eta vertical bar <0.80 and 0.5 <p(T) <10 GeV/c is presented. These momenta are much lower than previous measurements at the LHC. No significant difference between pp and p-Pb is observed, with PYTHIA 8.2 describing both data sets within uncertainties. This measurement constrains nuclear effects on the parton fragmentation in p-Pb collisions, and provides a benchmark for future studies of Pb-Pb collisions.Peer reviewe

Multiplicity dependence of pi, K, and p production in pp collisions at root s=13 TeV

This paper presents the measurements of pi(+/-), K-+/-, p and (p) over bar transverse momentum (p(T)) spectra as a function of charged-particle multiplicity density in proton-proton (pp) collisions at root s = 13 TeV with the ALICE detector at the LHC. Such study allows us to isolate the center-ofmass energy dependence of light-flavour particle production. The measurements reported here cover a pT range from 0.1 to 20 GeV/c and are done in the rapidity interval | y| <0.5. The p(T)-differential particle ratios exhibit an evolution with multiplicity, similar to that observed in pp collisions at v s = 7 TeV, which is qualitatively described by some of the hydrodynamical and pQCD-inspired models discussed in this paper. Furthermore, the pT-integrated hadron-to-pion yield ratios measured in pp collisions at two different center-of-mass energies are consistent when compared at similar multiplicities. This also extends to strange and multi-strange hadrons, suggesting that, at LHC energies, particle hadrochemistry scales with particle multiplicity the same way under different collision energies and colliding systems.Peer reviewe

Higher harmonic non-linear flow modes of charged hadrons in Pb-Pb collisions at root s(NN)=5.02 TeV

Anisotropic flow coefficients, nu(n), non-linear flow mode coefficients, chi(n,mk), and correlations among different symmetry planes, rho(n,mk) are measured in Pb-Pb collisions at root s(NN) = 5.02TeV. Results obtained with multi-particle correlations are reported for the transverse momentum interval 0.2 <p(T) <5.0 GeV/c within the pseudorapidity interval 0.4 <vertical bar eta vertical bar <0.8 as a function of collision centrality. The nu(n) coefficients and chi(n,mk) and rho(n,mk) are presented up to the ninth and seventh harmonic order, respectively. Calculations suggest that the correlations measured in different symmetry planes and the non-linear flow mode coefficients are dependent on the shear and bulk viscosity to entropy ratios of the medium created in heavy-ion collisions. The comparison between these measurements and those at lower energies and calculations from hydrodynamic models places strong constraints on the initial conditions and transport properties of the system.Peer reviewe

Soft-Dielectron Excess in Proton-Proton Collisions at root s=13 TeV

A measurement of dielectron production in proton-proton (pp) collisions at root s = 13 TeV, recorded with the ALICE detector at the CERN LHC, is presented in this Letter. The data set was recorded with a reduced magnetic solenoid field. This enables the investigation of a kinematic domain at low dielectron (ee) invariant mass m(ee) and pair transverse momentum p(T,ee) that was previously inaccessible at the LHC. The cross section for dielectron production is studied as a function of m(ee), p(T,ee), and event multiplicity dNch=d.. The expected dielectron rate from hadron decays, called hadronic cocktail, utilizes a parametrization of the measured eta/pi(0) ratio in pp and proton-nucleus collisions, assuming that this ratio shows no strong dependence on collision energy at low transverse momentum. Comparison of the measured dielectron yield to the hadronic cocktail at 0.15 < m(ee) < 0.6 GeV/c(2) and for p(T,ee) < 0.4 GeV/c indicates an enhancement of soft dielectrons, reminiscent of the "anomalous" soft-photon and soft-dilepton excess in hadron-hadron collisions reported by several experiments under different experimental conditions. The enhancement factor over the hadronic cocktail amounts to 1.61 +/- 0.13(stat) +/- 0.17(syst, data) +/- 0.34osyst; cocktailTHORN in the ALICE acceptance. Acceptance-corrected excess spectra in mee and pT; ee are extracted and compared with calculations of dielectron production from hadronic bremsstrahlung and thermal radiation within a hadronic many-body approach.Peer reviewe

Investigation of the p-Sigma(0) interaction via femtoscopy in pp collisions

This Letter presents the first direct investigation of the p-Sigma(0) interaction, using the femtoscopy technique in high-multiplicity pp collisions at root s = 13 TeV measured by the ALICE detector. The Sigma(0) is reconstructed via the decay channel to Lambda gamma, and the subsequent decay of Lambda to p pi(-). The photon is detected via the conversion in material to e(+)e(-) pairs exploiting the capability of the ALICE detector to measure electrons at low transverse momenta. The measured p-Sigma(0) correlation indicates a shallow strong interaction. The comparison of the data to several theoretical predictions obtained employing the Correlation Analysis Tool using the Schrodinger Equation (CATS) and the Lednicky-Lyuboshits approach shows that the current experimental precision does not yet allow to discriminate between different models, as it is the case for the available scattering and hypernuclei data. Nevertheless, the p-Sigma(0) correlation function is found to be sensitive to the strong interaction, and driven by the interplay of the different spin and isospin channels. This pioneering study demonstrates the feasibility of a femtoscopic measurement in the p-Sigma(0) channel and with the expected larger data samples in LHC Run 3 and Run 4, the p-Sigma(0) interaction will be constrained with high precision. (C) 2020 European Organization for Nuclear Research. Published by Elsevier B.V.Peer reviewe