The production cross section of prompt Λc+ charm baryons was measured with the ALICE detector at the LHC at midrapidity in proton-proton (pp) and proton-lead (p-Pb) collisions at a center-of-mass ...energy per nucleon pair of sNN=5.02TeV. The Λc+ and Λ¯c- baryons were reconstructed in the hadronic decay channels Λc+→pK-π+ and Λc+→pKS0 and respective charge conjugates. The measured differential cross sections as a function of transverse momentum (pT) and the pT-integrated Λc+ production cross section in pp and in p-Pb collisions are presented. The Λc+ nuclear modification factor (RpPb), calculated from the cross sections in pp and in p-Pb collisions, is presented and compared with the RpPb of D mesons. The Λc+/D0 ratio is also presented and compared with the light-flavor baryon-to-meson ratios p/π and Λ/KS0, and measurements from other LHC experiments. The results are compared to predictions from model calculations and Monte Carlo event generators.
The polarization of the Λ and ¯Λ hyperons along the beam (z) direction, Pz, has been measured in Pb-Pb collisions at √sNN=5.02 TeV recorded with ALICE at the Large Hadron Collider (LHC). The main ...contribution to Pz comes from elliptic flow-induced vorticity and can be characterized by the second Fourier sine coefficient Pz,s2=⟨Pzsin(2φ−2Ψ2)⟩, where φ is the hyperon azimuthal emission angle and Ψ2 is the elliptic flow plane angle. We report the measurement of Pz,s2 for different collision centralities and in the 30%–50% centrality interval as a function of the hyperon transverse momentum and rapidity. The Pz,s2 is positive similarly as measured by the STAR Collaboration in Au-Au collisions at √sNN=200 GeV, with somewhat smaller amplitude in the semicentral collisions. This is the first experimental evidence of a nonzero hyperon Pz in Pb-Pb collisions at the LHC. The comparison of the measured Pz,s2 with the hydrodynamic model calculations shows sensitivity to the competing contributions from thermal and the recently found shear-induced vorticity, as well as to whether the polarization is acquired at the quark-gluon plasma or the hadronic phase.
We report on the first femtoscopic measurement of baryon pairs, such as p−p, p−Λ, and Λ−Λ, measured by ALICE at the Large Hadron Collider (LHC) in proton-proton collisions at √s=7TeV. This study ...demonstrates the feasibility of such measurements in pp collisions at ultrarelativistic energies. The femtoscopy method is employed to constrain the hyperon-nucleon and hyperon-hyperon interactions, which are still rather poorly understood. A new method to evaluate the influence of residual correlations induced by the decays of resonances and experimental impurities is hereby presented. The p−p, p−Λ, and Λ−Λ correlation functions were fitted simultaneously with the help of a new tool developed specifically for the femtoscopy analysis in small colliding systems: Correlation Analysis Tool using the Schrödinger equation (CATS). Within the assumption that in pp collisions the three particle pairs originate from a common source, its radius is found to be equal to r0=1.125±0.018(stat)+0.058−0.035(syst) fm. The sensitivity of the measured p−Λ correlation is tested against different scattering parameters, which are defined by the interaction among the two particles, but the statistics is not sufficient yet to discriminate among different models. The measurement of the Λ−Λ correlation function constrains the phase space spanned by the effective range and scattering length of the strong interaction. Discrepancies between the measured scattering parameters and the resulting correlation functions at LHC and RHIC energies are discussed in the context of various models.
The study of nuclei and antinuclei production has proven to be a powerful tool to investigate the formation mechanism of loosely bound states in high-energy hadronic collisions. The first measurement ...of the production of HΛ3 in p-Pb collisions at sNN=5.02 TeV is presented in this Letter. Its production yield measured in the rapidity interval -1
Background
There is poor knowledge on the association between combined lifestyles with mortality risk among individuals at high risk, and little is known on the biological mechanisms that could be on ...the pathway.
Methods
Longitudinal analysis on 22 839 individuals from the Moli‐sani Study (Italy, 2005–2010). Among them, we identified 5200 elderly individuals (≥65 year), 2127 subjects with diabetes and 1180 with cardiovascular disease (CVD) at baseline. A healthy lifestyle score (HLS) was calculated, allocating 1 point for each of the following: abstention from smoking; adherence to Mediterranean diet; physical activity; absence of abdominal obesity. Hazard ratios (HR) with 95% confidence intervals (95%CI) were calculated by multivariable Cox regression and competing risk models.
Results
During 8.2 years of follow‐up, 1237 deaths occurred. In the general population, adherence to all four healthy lifestyles, compared with none or 1, was associated with lower risk of all‐cause (HR = 0.53; 95%CI:0.39–0.72), CVD (HR = 0.54; 0.32–0.91), cancer (HR = 0.62; 0.39–1.00) and mortality from other causes (HR = 0.39; 0.19–0.81). A 1‐point increase in HLS was associated with 20%, 22% and 24% lower risk of total mortality among the elderly, in subjects with diabetes or CVD, respectively. Traditional (e.g. blood lipids), inflammatory (e.g. C‐reactive protein) and novel biomarkers (e.g. markers of cardiac damage) accounted for up to 24% of the association of HLS with all‐cause mortality risk in the general population.
Conclusions
The impact of combined four healthy lifestyles on survival was considerable, both in the general population and among high‐risk subgroups. Inflammatory and novel biomarkers of CVD risk explained a substantial proportion of this association.
A
bstract
We present the measurement of a new set of jet shape observables for track-based jets in central Pb-Pb collisions at
s
N
N
=
2.76
TeV. The set of jet shapes includes the first radial moment ...or angularity,
g
; the momentum dispersion,
p
T
D
; and the difference between the leading and sub-leading constituent track transverse momentum,
LeSub
. These observables provide complementary information on the jet fragmentation and can constrain different aspects of the theoretical description of jet-medium interactions. The jet shapes were measured for a small resolution parameter
R
= 0
.
2 and were fully corrected to particle level. The observed jet shape modifications indicate that in-medium fragmentation is harder and more collimated than vacuum fragmentation as obtained by PYTHIA calculations, which were validated with the measurements of the jet shapes in proton-proton collisions at
s
=
7
TeV. The comparison of the measured distributions to templates for quark and gluon-initiated jets indicates that in-medium fragmentation resembles that of quark jets in vacuum. We further argue that the observed modifications are not consistent with a totally coherent energy loss picture where the jet loses energy as a single colour charge, suggesting that the medium resolves the jet structure at the angular scales probed by our measurements (
R
= 0
.
2). Furthermore, we observe that small-
R
jets can help to isolate purely energy loss effects from other effects that contribute to the modifications of the jet shower in medium such as the correlated background or medium response.
The production yield of the Λ (1520) baryon resonance is measured at midrapidity in Pb-Pb collisions at s NN = 2.76 TeV with the ALICE detector at the Large Hadron Collider (LHC). The measurement is ...performed in the Λ (1520)→ p K - (and charge conjugate) hadronic decay channel as a function of the transverse momentum ( p T ) and collision centrality. The ratio of the p T -integrated production of Λ (1520) baryons relative to Λ baryons in central collisions is suppressed by about a factor of 2 with respect to peripheral collisions. This is the first observation of the suppression of a baryonic resonance at the LHC and the first 3σ evidence of Λ (1520) suppression within a single collision system. The measured Λ (1520)/ Λ ratio in central collisions is smaller than the value predicted by the statistical hadronization model calculations. The shape of the measured p T distribution and the centrality dependence of the suppression are reproduced by the EPOS3 Monte Carlo event generator. The measurement adds further support to the formation of a dense hadronic phase in the final stages of the evolution of the fireball created in heavy-ion collisions, lasting long enough to cause a significant reduction in the observable yield of short-lived resonances.
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