The transport properties of quark-gluon plasma created in relativistic heavy-ion collisions are quantified by an improved global Bayesian analysis using the CERN Large Hadron Collider Pb–Pb data at ...sNN=2.76 and 5.02 TeV. The results show that the uncertainty of the extracted transport coefficients is significantly reduced by including new sophisticated collective flow observables from two collision energies for the first time. This work reveals the stronger temperature dependence of specific shear viscosity, a lower value of specific bulk viscosity, and a higher hadronization switching temperature than in the previous studies. The sensitivity analysis confirms that the precision measurements of higher-order harmonic flow and their correlations are crucial in extracting accurate values of the transport properties.
This Letter presents the first experimental observation of the attractive strong interaction between a proton and a multistrange baryon (hyperon) Ξ−. The result is extracted from two-particle ...correlations of combined p−Ξ−⊕p¯−Ξ¯+ pairs measured in p−Pb collisions at sNN=5.02 TeV at the LHC with ALICE. The measured correlation function is compared with the prediction obtained assuming only an attractive Coulomb interaction and a standard deviation in the range 3.6, 5.3 is found. Since the measured p−Ξ−⊕p¯−Ξ¯+ correlation is significantly enhanced with respect to the Coulomb prediction, the presence of an additional, strong, attractive interaction is evident. The data are compatible with recent lattice calculations by the HAL-QCD Collaboration, with a standard deviation in the range 1.8, 3.7. The lattice potential predicts a shallow repulsive Ξ− interaction within pure neutron matter and this implies stiffer equations of state for neutron-rich matter including hyperons. Implications of the strong interaction for the modeling of neutron stars are discussed.
We report the differential charged jet cross section and jet fragmentation distributions measured with the ALICE detector in proton-proton collisions at a center-of-mass energy √ s = 7 TeV. Jets with ...pseudorapidity | η | < 0.5 are reconstructed from charged particles using the anti- k T jet-finding algorithm with a resolution parameter R = 0.4. The jet cross section is measured in the transverse momentum interval 5 ≤ pch jetT < 100 GeV / c. Jet fragmentation is studied measuring the scaled transverse momentum spectra of the charged constituents of jets in four intervals of jet transverse momentum between 5 and 30 GeV / c. The measurements are compared to calculations from the pythia model as well as next-to-leading-order perturbative QCD calculations with powheg+pythia8. The charged jet cross section is well described by powheg for the entire measured range of pch jetT. For pch jetT > 40 GeV / c, the pythia calculations also agree with the measured charged jet cross section. pythia6 simulations describe the fragmentation distributions to 15%. Larger discrepancies are observed for pythia8.
The production cross sections of D0 and Λ+c hadrons originating from beauty-hadron decays (i.e., nonprompt) were measured for the first time at midrapidity (|y|<0.5) by the ALICE Collaboration in ...proton-proton collisions at a center-of-mass energy √s=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¯b production cross section per unit of rapidity at midrapidity, estimated from these measurements, is dσb¯b/dy||y|<0.5=83.1±3.5(stat)±5.4(syst)+12.3−3.2(extrap) μb. The baryon-to-meson ratios are computed to investigate the hadronization mechanism of beauty quarks. The nonprompt Λ+c/D0 production ratio has a similar trend to the one measured for the promptly produced charmed particles and to the p/π+ and Λ/K0S ratios, suggesting a similar baryon-formation mechanism among light, strange, charm, and beauty hadrons. The pT -integrated nonprompt Λ+c/D0 ratio is found to be significantly higher than the one measured in e+e− collisions.
A measurement of dielectron production in proton-proton (pp) collisions at √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 mee and pair transverse momentum pT,ee that was previously inaccessible at the LHC. The cross section for dielectron production is studied as a function of mee, pT,ee, and event multiplicity dNch/dη. The expected dielectron rate from hadron decays, called hadronic cocktail, utilizes a parametrization of the measured η/π0 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 < mee < 0.6 GeV / c2 and for pT,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) ± 0.34 (syst, cocktail) in the ALICE acceptance. Acceptance-corrected excess spectra in m ee and pT,ee are extracted and compared with calculations of dielectron production from hadronic bremsstrahlung and thermal radiation within a hadronic many-body approach.
We studied the short- and long-term effects of imatinib in hospitalised COVID-19 patients.
Participants were randomised to receive standard of care (SoC) or SoC with imatinib. Imatinib dosage was ...400mg daily until discharge (max 14 days). Primary outcomes were mortality at 30 days and 1 year. Secondary outcomes included recovery, quality of life and long COVID symptoms at 1 year. We also performed a systematic review and meta-analysis of randomised trials studying imatinib for 30-day mortality in hospitalised COVID-19 patients.
We randomised 156 patients (73 in SoC and 83 in imatinib). Among patients on imatinib, 7.2% had died at 30 days and 13.3% at 1 year and in SoC 4.1% and 8.2% (adjusted HR 1.35, 95% CI 0.47–3.90). At 1-year, self-reported recovery occurred in 79.0% in imatinib and in 88.5% in SoC (RR 0.91, 0.78-1.06). We found no convincing difference in quality of life or symptoms. Fatigue (24%) and sleep issues (20%) frequently bothered patients at one year. In the meta-analysis, imatinib was associated with a mortality risk ratio of 0.73 (0.32–1.63; low certainty evidence).
The evidence raises doubts regarding benefit of imatinib in reducing mortality, improving recovery and preventing long COVID symptoms in hospitalised COVID-19 patients.
•We found no short or long-term benefit from imatinib in hospitalised COVID-19.•Pooled evidence raises doubts regarding benefit of imatinib in reducing mortality.•Fatigue and sleeping problems common at 1 year after hospitalised COVID-19.
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