Mass discrimination using double-sided silicon microstrip detectors for pions and protons at intermediate energies

Prototype silicon detector modules for the vertex detector of the FINUDA experiment were tested at TRIUMF using pions and protons at 270 and 408 MeV/c in order to study their use for mass discrimination based on energy deposition. The detector modules were constructed using double-sided silicon detectors based on the ALEPH design, read out by VA1 integrated circuits. The test modules and apparatus are described, details of the data analysis are discussed, and the results are presented together with GEANT simulations. Particular attention is given to the detector response for the various particles, with signals ranging from the minimum-ionising pions at 408 MeV/c up to 20 times minimum-ionising for the protons at 270 MeV/c. ( 1999 Elsevier Science B.V. All rights reserved

Energy dependence and fluctuations of anisotropic flow in Pb-Pb collisions at 1asNN = 5.02 and 2.76 TeV

Measurements of anisotropic flow coefficients with two- and multi-particle cu- mulants for inclusive charged particles in Pb\u2013Pb collisions at 1asNN = 5.02 and 2.76 TeV are reported in the pseudorapidity range |\u3b7| < 0.8 and transverse momentum 0.2 < pT < 50 GeV/c. The full data sample collected by the ALICE detector in 2015 (2010), corre- sponding to an integrated luminosity of 12.7 (2.0) \u3bcb 121 in the centrality range 0\u201380%, is analysed. Flow coefficients up to the sixth flow harmonic (v6) are reported and a de- tailed comparison among results at the two energies is carried out. The pT dependence of anisotropic flow coefficients and its evolution with respect to centrality and harmonic number n are investigated. An approximate power-law scaling of the form vn(pT) 3c pn/3 T is observed for all flow harmonics at low pT (0.2 < pT < 3 GeV/c). At the same time, the ratios v /vn/m are observed to be essentially independent of p for most centralities up to nmT about pT = 10 GeV/c. Analysing the differences among higher-order cumulants of elliptic flow (v2), which have different sensitivities to flow fluctuations, a measurement of the stan- dardised skewness of the event-by-event v2 distribution P(v2) is reported and constraints on its higher moments are provided. The Elliptic Power distribution is used to parametrise P(v2), extracting its parameters from fits to cumulants. The measurements are compared to different model predictions in order to discriminate among initial-state models and to constrain the temperature dependence of the shear viscosity to entropy-density ratio

Azimuthally-differential pion femtoscopy relative to the third harmonic event plane in Pb\u2013Pb collisions at 1asNN = 2.76TeV

Azimuthally-differential femtoscopic measurements, being sensitive to spatio-temporal characteristics of the source as well as to the collective velocity fields at freeze out, provide very important information on the nature and dynamics of the system evolution. While the HBT radii oscillations relative to the second harmonic event plane measured recently reflect mostly the spatial geometry of the source, model studies have shown that the HBT radii oscillations relative to the third harmonic event plane are predominantly defined by the velocity fields. In this Letter, we present the first results on azimuthally-differential pion femtoscopy relative to the third harmonic event plane as a function of the pion pair transverse momentum kT for different collision centralities in Pb\u2013Pb collisions at 1asNN = 2.76 TeV. We find that the Rside and Rout radii, which characterize the pion source size in the directions perpendicular and parallel to the pion transverse momentum, oscillate in phase relative to the third harmonic event plane, similar to the results from 3+1D hydrodynamical calculations. The observed radii oscillations unambiguously signal a collective expansion and anisotropy in the velocity fields. A comparison of the measured radii oscillations with the Blast-Wave model calculations indicate that the initial state triangularity is washed- out at freeze out

Inclusive J/\u3c8 production in Xe\u2013Xe collisions at 1asNN = 5.44 TeV

Inclusive J/\u3c8 production is studied in Xe\u2013Xe interactions at a centre-of-mass energy per nucleon pair of 1asNN = 5.44 TeV, using the ALICE detector at the CERN LHC. The J/\u3c8 meson is reconstructed via its decay into a muon pair, in the centre-of-mass rapidity interval 2.5 < y < 4 and down to zero transverse momentum. In this Letter, the nuclear modification factors RAA for inclusive J/\u3c8, measured in the centrality range 0\u201390% as well as in the centrality intervals 0\u201320% and 20\u201390% are presented. The RAA values are compared to previously published results for Pb\u2013Pb collisions at 1asNN = 5.02 TeV and to the calculation of a transport model. A good agreement is found between Xe\u2013Xe and Pb\u2013Pb results as well as between data and the model

Constraints on jet quenching in p\u2013Pb collisions at 1asNN = 5.02\u2009TeV measured by the event-activity dependence of semi-inclusive hadron-jet distributions

The ALICE Collaboration reports the measurement of semi-inclusive distributions of charged-particle jets recoiling from a high-transverse momentum trigger hadron in p\u2013Pb collisions at 1asNN = 5.02 TeV. Jets are reconstructed from charged-particle tracks using the anti-kT algorithm with resolution parameter R = 0.2 and 0.4. A data-driven statistical approach is used to correct the uncorrelated background jet yield. Recoil jet distributions are reported for jet transverse momentum 15 < pch < 50 GeV/c and are compared in T,jet various intervals of p\u2013Pb event activity, based on charged-particle multiplicity and zero-degree neutral energy in the forward (Pb-going) direction. The semi-inclusive observable is self-normalized and such comparisons do not require the interpretation of p\u2013Pb event activity in terms of collision geometry, in contrast to inclusive jet observables. These measurements provide new constraints on the magnitude of jet quenching in small systems at the LHC. In p\u2013Pb collisions with high event activity, the average medium-induced out-of-cone energy transport for jets with R = 0.4 and 15 < pch < 50 GeV/c is T,jet measured to be less than 0.4 GeV/c at 90% confidence, which is over an order of magnitude smaller than a similar measurement for central Pb\u2013Pb collisions at 1asNN =2.76TeV. Comparison is made to theoretical calculations of jet quenching in small systems, and to inclusive jet measurements in p\u2013Pb collisions selected by event activity at the LHC and in d\u2013Au collisions at RHIC

Semiexclusive pionic double charge exchange on 4 He

The semiexclusive reaction {}^{4}\mathrm{He}({\ensuremath{\pi}}^{+},{\ensuremath{\pi}}^{\ensuremath{-}}pp)pp has been studied at pion kinetic energies of 105 MeV and 115 MeV. Signatures from the production of the hypothetical \ensuremath{\pi}\mathrm{NN} resonance {d}^{\ensuremath{'}} have been searched for in the invariant mass {M}_{\ensuremath{\pi}\mathrm{pp}} spectra. No hint for a dominant {d}^{\ensuremath{'}} production, as anticipated from double charge exchange excitation functions on nuclei, has been found. The data are satisfactorily described by sequential single charge exchange

Temperature measurement of fragment emitting systems in Au+Au 35 MeV/nucleon collisions

We report on the results of experiments performed to investigate the Au1Au 35 MeV/nucleon reaction. The reaction products generated in the disassembly of the unique source formed in central collisions and those coming from the decay of the quasiprojectile in peripheral and midperipheral ones ~five different impact parameters! were identified through a careful data selection based on the study of energy and angular distributions. The excitation energies of the fragment sources have been extracted through a calorimetric method and by means of a comparison with model calculations. The nuclear temperatures of these decaying systems have been measured from the relative isotopic abundances and, also for central collisions, from the relative populations of excited states. The temperatures of the quasiprojectile disassembling systems are slowly increasing going towards smaller impact parameter. The relationship between temperature and excitation energy seems to be almost independent of the characteristics of the emitting source. The extracted caloric curve shows a slow monotonic increase with increasing excitation energy. A comparison with data derived from Au fragmentation at much higher incident energies is discussed. @S0556-2813~98!04408-2

Elliptic flow of charged particles in Pb-Pb collisions at 2.76 TeV

We report the first measurement of charged particle elliptic flow in Pb-Pb collisions at 2.76 TeV with the ALICE detector at the CERN Large Hadron Collider. The measurement is performed in the central pseudorapidity region (|$\eta$|<0.8) and transverse momentum range 0.2< $p_{\rm T}$< 5.0 GeV/$c$. The elliptic flow signal v$_2$, measured using the 4-particle correlation method, averaged over transverse momentum and pseudorapidity is 0.087 $\pm$ 0.002 (stat) $\pm$ 0.004 (syst) in the 40-50% centrality class. The differential elliptic flow v$_2(p_{\rm T})$ reaches a maximum of 0.2 near $p_{\rm T}$ = 3 GeV/$c$. Compared to RHIC Au-Au collisions at 200 GeV, the elliptic flow increases by about 30%. Some hydrodynamic model predictions which include viscous corrections are in agreement with the observed increase.Comment: 10 pages, 4 captioned figures, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/389

New results on mesonic weak decay of p-shell Λ-hypernuclei

n/

Graphene in Lithium-Ion/Lithium-Sulfur Batteries

In order to deal with the energy demand of the increasing global population,the use of sustainable sources of energy has become mandatory to attenuate theenvironmental problems that come along with the use of fossil sources of energy.However, one of the problems of renewable energy sources, such as wind or sun,is that they are intermittent. So, in order to make the best use of them, we needgood energy storage systems able to capture, manage and store energy at a largescale and low cost. If we are also capable of replacing the gasoline powered transportationwith electric vehicles, the greenhouse emissions would be significantlyreduced. As well, it is necessary a change in the energetic matrix for stationarydevices to solve the transport cost and the greenhouse emission provokes for theuse of natural gas. Considering this, the major promises to accomplish the needsof high gravimetric, volumetric and power density is given by lithium batteries.In the past decades and up to nowadays, they have become the energy source ofalmost all electronic portable devices and made possible a huge number of technologicalapplications. Graphene based materials, due to their unique properties,have become of great interest to be used in different components of the battery:anode, cathode and separator. As part of the electrodes, used adequately, graphenematerials improve the electron and ionic mobility providing not only higher electricalconductivity, but also higher capacity. Due to the rich carbon chemistry,graphene can be easily functionalized with different groups leading to changes inits properties. In this sense, the nano-sized dimension and elevated specific surfacearea makes it a perfect candidate for improving conductivity, connectivity andlithium-ion transport in both cathode and anode active materials. Functionalizedgraphene is also used in the modification of separators of lithium-sulfur batteriesfor the suppression of the polysulfide shuttle mechanism due to its interaction/repulsion with the charged intermediate polysulfide species. This chapter presentsa critical overview of the state-of-art in the optimization and application ofgraphene derived materials for anodes, cathodes and separators in lithium batteries.Besides a thorough description of novel designs and general discussion of theattained electrochemical performances, this chapter also aims to discuss desiredproperties and current drawbacks for massive industrial application in lithiumbatteries.Fil: Luque, Guillermina Leticia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Para, Maria Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Primo, Emiliano Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Calderón, Andrea Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Bracamonte, Maria Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Otero, Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Rojas, María del Carmen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: García Soriano, Francisco Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Lener, German. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentin