We report the charge-changing cross sections (σcc) of 24 p-shell nuclides on both hydrogen and carbon at about 900A MeV, of which 8,9Li, 10-12Be, 10,14,15B, 14,15,17-22N and 16O on hydrogen and 8,9Li on carbon are for the first time. Benefiting from the data set, we found a new and robust relationship between the scaling factor of the Glauber model calculations and the separation energies of the nuclei of interest on both targets. This allows us to deduce proton radii (Rp) for the first time from the cross sections on hydrogen. Nearly identical Rp values are deduced from both target data for the neutron-rich carbon isotopes; however, the Rp from the hydrogen target is systematically smaller in the neutron-rich nitrogen isotopes. This calls for further experimental and theoretical investigations.

The production of $\mathrm{K}^{*}(\mathrm{892})^{0}$ and $\mathrm{\phi(1020)}$ in pp collisions at $\sqrt{s}$ = 8 TeV was measured using Run 1 data collected by the ALICE collaboration at the LHC. The $p_{\rm{T}}$-differential yields d$^{\rm 2}N$/d$y$d$p_{\rm{T}}$ in the range $0 < p_{\rm{T}} < 20$ GeV/$c$ for $\rm{K}^{*0}$ and $0.4 < p_{\rm{T}} < 16$ GeV/$c$ for $\phi$ have been measured at midrapidity, $|y| < 0.5$. Moreover, improved measurements of the $\rm{K}^{*}(892)^{0}$ and $\phi(1020)$ at $\sqrt{s} = 7$TeV are presented. The collision energy dependence of $p_{\rm{T}}$ distributions, $p_{\rm{T}}$-integrated yields and particle ratios in inelastic pp collisions are examined. The results are also compared with different collision systems. The values of the particle ratios are found to be similar to those measured at other LHC energies. In pp collisions a hardening of the particle spectra is observed with increasing energy, but at the same time it is also observed that the relative particle abundances are independent of the collision energy. The $p_{\rm{T}}$-differential yields of $\rm{K}^{*0}$ and $\phi$ in pp collisions at $\sqrt{s} = 8$ TeV are compared with the expectations of different Monte Carlo event generators.

The global polarization of the $\\Lambda$ and $\\overline\\Lambda$ hyperons is measured for Pb-Pb collisions at $\\sqrt{s_{\\rm{NN}}}$ = 2.76 and 5.02 TeV recorded with the ALICE at the LHC. The results are reported differentially as a function of collision centrality and hyperon\u0027s transverse momentum ($p_{\\rm{T}}$) for the range of centrality 5-50%, $0.5 \u003c p_{\\rm{T}} \u003c5$ GeV/$c$, and rapidity $|y|\u003c0.5$. The hyperon global polarization averaged for Pb-Pb collisions at $\\sqrt{s_{\\rm{NN}}}$ = 2.76 and 5.02 TeV is found to be consistent with zero, $\\langle P_{\\rm{H}}\\rangle$ (%) $\\approx$ 0.01 $\\pm$ 0.06 (stat.) $\\pm$ 0.03 (syst.) in the collision centrality range 15-50%, where the largest signal is expected. The results are compatible with expectations based on an extrapolation from measurements at lower collision energies at RHIC, hydrodynamical model calculations, and empirical estimates based on collision energy dependence of directed flow, all of which predict the global polarization values at LHC energies of the order of 0.01%.

Measurement of root-mean-square radii of proton distributions of 17–22 N from charge-changing cross section shows the emergence of thick neutron skin towards the neutron-drip line. Signature of N = 14 shell gap has been found in nitrogen isotopes along with the emergence of neutron halo in 22 N. The measured radii are in good agreement with the shell model calculations.

An improved value for the lifetime of the (anti-)hypertriton has been obtained using the data sample of Pb–Pb collisions at sNN=5.02 TeV collected by the ALICE experiment at the LHC. The (anti-)hypertriton has been reconstructed via its charged two-body mesonic decay channel and the lifetime has been determined from an exponential fit to the d N /d( ct ) spectrum. The measured value, τ=242−38+34 (stat.) ± 17 (syst.) ps, is compatible with representative theoretical predictions, thus contributing to the solution of the longstanding hypertriton lifetime puzzle.

A measurement of the production of prompt $Lambda_{rm c}^{+}$ baryons in Pb-Pb collisions at $sqrt{s_{rm NN}} = 5.02 $ TeV with the ALICE detector at the LHC is reported. The $Lambda_{rm c}^{+}$ and $overline{Lambda}_{rm c}^{-}$ were reconstructed at midrapidity ($|y| u003c 0.5$) via the hadronic decay channel $Lambda_{rm c}^{+}rightarrow {rm p} {rm K}_{rm S}^{0}$ (and charge conjugate) in the transverse momentum and centrality intervals $6 u003c p_{rm T} u003c12$ GeV/$c$ and 0-80%. The $Lambda_{rm c}^{+}$/D$^0$ ratio, which is sensitive to the charm quark hadronisation mechanisms in the medium, is measured and found to be larger than the ratio measured in minimum-bias pp collisions at $sqrt{s} = 7$ TeV and in p-Pb collisions at $sqrt{s_{rm NN}} = 5.02 $ TeV. In particular, the values in p-Pb and Pb-Pb collisions differ by about two standard deviations of the combined statistical and systematic uncertainties. The $Lambda_{rm c}^{+}$/D$^0$ ratio is also compared with model calculations including different implementations of charm quark hadronisation. The measured ratio is reproduced by models implementing a pure coalescence scenario, while adding a fragmentation contribution leads to an underestimation. The $Lambda_{rm c}^{+}$ nuclear modification factor, $R_{rm AA}$, is also presented. The measured values of the $R_{rm AA}$ of $Lambda_{rm c}^{+}$, D$_{rm s}^+$ and non-strange D mesons are compatible within the combined statistical and systematic uncertainties. They show, however, a hint of a hierarchy $(R_{rm AA}^{{rm D}^{0}}u003cR_{rm AA}^{{rm D}_{rm s}^+}u003cR_{rm AA}^{Lambda_{rm c}^{+}})$, conceivable with a contribution of recombination mechanisms to charm hadron formation in the medium.

We performed a missing-mass spectroscopy experiment of the 12C(p, d) reaction at 2.5 GeV proton energy in order to search for η′ mesic nuclei. An excitation-energy spectrum of 11C was obtained around the η′ production threshold. As no significant peak structure was observed in the spectrum, upper limits of the formation cross section of η′ mesic nuclei have been determined. Preliminary results of the experiment as well as future prospects are given.

Angular correlations between charged trigger and associated particles are measured by the ALICE detector in p-Pb collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV for transverse momentum ranges within 0.5 < P-T,P-assoc < P-T,P-trig < 4 GeV/c. The correlations are measured over two units of pseudorapidity and full azimuthal angle in different intervals of event multiplicity, and expressed as associated yield per trigger particle. Two long-range ridge-like structures, one on the near side and one on the away side, are observed when the per-trigger yield obtained in low-multiplicity events is subtracted from the one in high-multiplicity events. The excess on the near-side is qualitatively similar to that recently reported by the CMS Collaboration, while the excess on the away-side is reported for the first time. The two-ridge structure projected onto azimuthal angle is quantified with the second and third Fourier coefficients as well as by near-side and away-side yields and widths. The yields on the near side and on the away side are equal within the uncertainties for all studied event multiplicity and p(T) bins, and the widths show no significant evolution with event multiplicity or p(T). These findings suggest that the near-side ridge is accompanied by an essentially identical away-side ridge. (c) 2013 CERN. Published by Elsevier B.V. All rights reserved.

We present measurements of Underlying Event observables in pp collisions at \( \sqrt {s} = 0.9 \) and 7TeV. The analysis is performed as a function of the highest charged-particle transverse momentum p T,LT in the event. Different regions are defined with respect to the azimuthal direction of the leading (highest transverse momentum) track: Toward, Transverse and Away. The Toward and Away regions collect the fragmentation products of the hardest partonic interaction. The Transverse region is expected to be most sensitive to the Underlying Event activity. The study is performed with charged particles above three different p T thresholds: 0.15, 0.5 and 1.0 GeV/c. In the Transverse region we observe an increase in the multiplicity of a factor 2–3 between the lower and higher collision energies, depending on the track p T threshold considered. Data are compared to Pythia 6.4, Pythia 8.1 and Phojet. On average, all models considered underestimate the multiplicity and summed p T in the Transverse region by about 10–30%.

AbstractThe ALICE experiment at the LHC has studied J/ψproduction at mid-rapidity in pp collisions at$ \sqrt{s}=7 $TeV through its electron pair decay on a data sample corresponding to an integrated luminosityLint= 5.6 nb−1. The fraction of J/ψfrom the decay of long-lived beauty hadrons was determined for J/ψcandidates with transverse momentumpt>1.3 GeV/cand rapidity |y|<0.9. The cross section for prompt J/ψmesons, i.e. directly produced J/ψand prompt decays of heavier charmonium states such as theψ(2S) and χcresonances, is σprompt J/ψ(pt>1.3 GeV/c,|y|<0.9) = 8.3 ± 0.8 (stat.) ± 1.1 (syst.)$ _{-1.4}^{+1.5 } $(syst.pol.)μb. The cross section for the production of b-hadrons decaying to J/ψwithpt>1.3 GeV/cand |y|<0.9 is$ {\sigma_{{{J \left/ {{\psi \leftarrow {{\mathrm{h}}_{\mathrm{B}}}}} \right.}}}} $(pt> 1.3 GeV/c, |y| < 0.9) = 1.46 ± 0.38 (stat.)$ _{-0.32}^{+0.26 } $(syst.)μb. The results are compared to QCD model predictions. The shape of theptandydistributions of b-quarks predicted by perturbative QCD model calculations are used to extrapolate the measured cross section to derive the$ \mathrm{b}\overline{\mathrm{b}} $pair total cross section and dσ/dyat mid-rapidity.

For the slow extraction part of the beam diagnostics system of the Superconducting Projectile Fragment Separator (Super-FRS) of FAIR-facility a total of 32 detectors are needed. They will be used for beam monitoring, tracking and characterization of the produced ions. GEM-TPC detectors can perform over wide dynamic range without disturbing the beam and are thus suitable for this kind of in-beam detection. We present the simulations and first measurements with the GEMs of the Super-FRS GEM-TPC prototype.