36 research outputs found

    Growth and Puberty in Thalassemia Major

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    Growth and sexual development were evaluated in 54 (29 female, 25 male) patients with beta-thalassemia major aged 2.7-21.3 years (mean 10.4 yr). Mean pretransfusion hemoglobin concentration was 7.8 +/- 0.7 mg/dl. All patients except 6 were on desferrioxamine. Age of starting of therapy was 6.8 +/- 3.9 years, Mean SDS values for height, weight and sitting height were significantly lower (p2 SD below the mean) was observed in 36 out of 54 patients. Among 11 patients over 14 years, 9 showed delay in onset or progression of puberty and 10 had growth retardation. Height SDS were negatively correlated with chronological age, age of onset of desferrioxamine and present serum ferritin levels (p<0.001). These findings indicate that abnormal growth and delayed puberty are frequent in transfusion dependent thalassemics. These can be partly overcome by early onset of chelating therapy

    Probing the chiral magnetic wave with charge-dependent flow measurements in Pb-Pb collisions at the LHC

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    The Chiral MagneticWave (CMW) phenomenon is essential to provide insights into the strong interaction in QCD, the properties of the quark-gluon plasma, and the topological characteristics of the early universe, offering a deeper understanding of fundamental physics in high-energy collisions. Measurements of the charge-dependent anisotropic flow coefficients are studied in Pb-Pb collisions at center-of-mass energy per nucleon-nucleon collision v sNN = 5.02TeV to probe the CMW. In particular, the slope of the normalized difference in elliptic (v2) and triangular (v3) flow coefficients of positively and negatively charged particles as a function of their event-wise normalized number difference, is reported for inclusive and identified particles. The slope rNorm 3 is found to be larger than zero and to have a magnitude similar to rNorm 2, thus pointing to a large background contribution for these measurements. Furthermore, rNorm 2 can be described by a blast wave model calculation that incorporates local charge conservation. In addition, using the event shape engineering technique yields a fraction of CMW (fCMW) contribution to this measurement which is compatible with zero. This measurement provides the very first upper limit for fCMW, and in the 10-60% centrality interval it is found to be 26% (38%) at 95% (99.7%) confidence level

    First Measurement of the |t | Dependence of Incoherent J/Ļˆ Photonuclear Production

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    The first measurement of the cross section for incoherent photonuclear production of J/Ļˆ vector mesons as a function of the Mandelstam |t| variable is presented. The measurement was carried out with the ALICE detector at midrapidity, |y|<0.8, using ultraperipheral collisions of Pb nuclei at a center-of-mass energy per nucleon pair of sNN=5.02 TeV. This rapidity interval corresponds to a Bjorken-x range (0.3-1.4)Ɨ10-3. Cross sections are given in five |t| intervals in the range 0.04<|t|<1 GeV2 and compared to the predictions by different models. Models that ignore quantum fluctuations of the gluon density in the colliding hadron predict a |t| dependence of the cross section much steeper than in data. The inclusion of such fluctuations in the same models provides a better description of the data

    Study of flavor dependence of the baryon-to-meson ratio in proton-proton collisions at s=13ā€‰ā€‰TeV

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    The production cross sections of D0 and Ī›+c hadrons originating from beauty-hadron decays (i.e., nonprompt) were measured for the first time at midrapidity (|y|&lt;0.5) by the ALICE Collaboration in proton-proton collisions at a center-of-mass energy āˆšs=13 TeV. They are described within uncertainties by perturbative QCD calculations employing the fragmentation fractions of beauty quarks to baryons measured at forward rapidity by the LHCb Collaboration. The b Ģ„b production cross section per unit of rapidity at midrapidity, estimated from these measurements, is dĻƒb Ģ„b/dy||y|&lt;0.5=83.1Ā±3.5(stat)Ā±5.4(syst)+12.3āˆ’3.2(extrap) Ī¼b. The baryon-to-meson ratios are computed to investigate the hadronization mechanism of beauty quarks. The nonprompt Ī›+c/D0 production ratio has a similar trend to the one measured for the promptly produced charmed particles and to the p/Ļ€+ and Ī›/K0S ratios, suggesting a similar baryon-formation mechanism among light, strange, charm, and beauty hadrons. The pT -integrated nonprompt Ī›+c/D0 ratio is found to be significantly higher than the one measured in e+eāˆ’ collisions

    Measurement of the low-energy antitriton inelastic cross section

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    In this Letter, the first measurement of the inelastic cross section for antitritonā€“nucleus interactions is reported, covering the momentum range of 0.8ā‰¤p<2.4 GeV/c. The measurement is carried out using data recorded with the ALICE detector in pp and Pbā€“Pb collisions at a centre-of-mass energy per nucleon of 13 TeV and 5.02 TeV, respectively. The detector material serves as an absorber for antitriton nuclei. The raw yield of (anti)triton nuclei measured with the ALICE apparatus is compared to the results from detailed ALICE simulations based on the [Formula presented] toolkit for the propagation of (anti)particles through matter, allowing one to quantify the inelastic interaction probability in the detector material. This analysis complements the measurement of the inelastic cross section of antinuclei up to A=3 carried out by the ALICE Collaboration, and demonstrates the feasibility of the study of the isospin dependence of inelastic interaction cross section with the analysis techniques presented in this Letter

    Charged-particle production as a function of the relative transverse activity classifier in pp, pā€“Pb, and Pbā€“Pb collisions at the LHC

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    Measurements of charged-particle production in pp, pā€“Pb, and Pbā€“Pb collisions in the toward, away, and transverse regions with the ALICE detector are discussed. These regions are defined event-by-event relative to the azimuthal direction of the charged trigger particle, which is the reconstructed particle with the largest transverse momentum pTtrig in the range 8 < 15 GeV/c. The toward and away regions contain the primary and recoil jets, respectively; both regions are accompanied by the underlying event (UE). In contrast, the transverse region perpendicular to the direction of the trigger particle is dominated by the so-called UE dynamics, and includes also contributions from initial- and final-state radiation. The relative transverse activity classifier, RT=NchT/NchT, is used to group events according to their UE activity, where NchT is the charged-particle multiplicity per event in the transverse region and NchT is the mean value over the whole analysed sample. The energy dependence of the RT distributions in pp collisions at s = 2.76, 5.02, 7, and 13 TeV is reported, exploring the Koba-Nielsen-Olesen (KNO) scaling properties of the multiplicity distributions. The first measurements of charged-particle pT spectra as a function of RT in the three azimuthal regions in pp, pā€“Pb, and Pbā€“Pb collisions at sNN = 5.02 TeV are also reported. Data are compared with predictions obtained from the event generators PYTHIA 8 and EPOS LHC. This set of measurements is expected to contribute to the understanding of the origin of collective-like effects in small collision systems (pp and pā€“Pb)

    Femtoscopic correlations of identical charged pions and kaons in pp collisions at s =13 TeV with event-shape selection

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    Collective behavior has been observed in high-energy heavy-ion collisions for several decades. Collectivity is driven by the high particle multiplicities that are produced in these collisions. At the CERN Large Hadron Collider (LHC), features of collectivity have also been seen in high-multiplicity proton-proton collisions that can attain particle multiplicities comparable to peripheral Pb-Pb collisions. One of the possible signatures of collective behavior is the decrease of femtoscopic radii extracted from pion and kaon pairs emitted from high-multiplicity collisions with increasing pair transverse momentum. This decrease can be described in terms of an approximate transverse mass scaling. In the present work, femtoscopic analyses are carried out by the ALICE Collaboration on charged pion and kaon pairs produced in pp collisions at s=13TeV from the LHC to study possible collectivity in pp collisions. The event-shape analysis method based on transverse sphericity is used to select for spherical versus jetlike events, and the effects of this selection on the femtoscopic radii for both charged pion and kaon pairs are studied. This is the first time this selection method has been applied to charged kaon pairs. An approximate transverse-mass scaling of the radii is found in all multiplicity ranges studied when the difference in the Lorentz boost for pions and kaons is taken into account. This observation does not support the hypothesis of collective expansion of hot and dense matter that should only occur in high-multiplicity events. A possible alternate explanation of the present results is based on a scenario of common emission conditions for pions and kaons in pp collisions for the multiplicity ranges studied

    Emergence of Long-Range Angular Correlations in Low-Multiplicity Proton-Proton Collisions

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    This Letter presents the measurement of near-side associated per-trigger yields, denoted ridge yields, from the analysis of angular correlations of charged hadrons in proton-proton collisions at s=13 TeV. Long-range ridge yields are extracted for pairs of charged particles with a pseudorapidity difference of 1.4<|Ī”Ī·|<1.8 and a transverse momentum of 1<2 GeV/c, as a function of the charged-particle multiplicity measured at midrapidity. This Letter extends the measurements of the ridge yield to the low multiplicity region, where in hadronic collisions it is typically conjectured that a strongly interacting medium is unlikely to be formed. The precision of the new low multiplicity results allows for the first direct quantitative comparison with the results obtained in e+e- collisions at s=91 GeV and s=183-209 GeV, where initial-state effects such as preequilibrium dynamics and collision geometry are not expected to play a role. In the multiplicity range

    System-size dependence of the hadronic rescattering effect at energies available at the CERN Large Hadron Collider

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    The first measurements of Kāˆ—(892)0 resonance production as a function of charged-particle multiplicity in Xe-Xe collisions at sNN=5.44 TeV and pp collisions ats=5.02 TeV using the ALICE detector are presented. The resonance is reconstructed at midrapidity (|y| < 0.5) using the hadronic decay channel Kāˆ—0 ā†’KĀ±Ļ€āˆ“. Measurements of transverse-momentum integrated yield, mean transverse-momentum, nuclear modification factor of Kāˆ—0, and yield ratios of resonance to stable hadron (Kāˆ—0/K) are compared across different collision systems (pp, p-Pb, Xe-Xe, and Pb-Pb) at similar collision energies to investigate how the production of Kāˆ—0 resonances depends on the size of the system formed in these collisions. The hadronic rescattering effect is found to be independent of the size of colliding systems and mainly driven by the produced charged-particle multiplicity, which is a proxy of the volume of produced matter at the chemical freeze-out. In addition, the production yields of Kāˆ—0 in Xe-Xe collisions are utilized to constrain the dependence of the kinetic freeze-out temperature on the system size using the hadron resonance gas-partial chemical equilibrium model

    Pseudorapidity dependence of anisotropic flow and its decorrelations using long-range multiparticle correlations in Pbā€“Pb and Xeā€“Xe collisions

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    The pseudorapidity dependence of elliptic (v2), triangular (v3), and quadrangular (v4) flow coefficients of charged particles measured in Pbā€“Pb collisions at a centre-of-mass energy per nucleon pair of sNN=5.02TeV and in Xeā€“Xe collisions at sNN=5.44TeV with ALICE at the LHC are presented. The measurements are performed in the pseudorapidity range āˆ’3.5<Ī·<5 for various centrality intervals using two- and multi-particle cumulants with the subevent method. The flow probability density function (p.d.f.) is studied with the ratio of flow coefficient v2 calculated with four- and two-particle cumulant, and suggests that the variance of flow p.d.f. is independent of pseudorapidity. The decorrelation of the flow vector in the longitudinal direction is probed using two-particle correlations. The results measured with respect to different reference regions in pseudorapidity exhibit differences, argued to be a result of saturating decorrelation effect above a certain pseudorapidity separation, in contrast to previous publications which assign this observation to non-flow effects. The results are compared to 3+1 dimensional hydrodynamic and the AMPT transport model calculations. Neither of the models is able to simultaneously describe the pseudorapidity dependence of measurements of anisotropic flow and its fluctuations. The results presented in this work highlight shortcomings in our current understanding of initial conditions and subsequent system expansion in the longitudinal direction. Therefore, they provide input for its improvement
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