Long-range angular correlationsof \u3c0, K and p in p\u2013Pb collisions at 1asNN =5.02TeV

Angular correlations between unidentified charged trigger particles and various species of charged associated particles (unidentified particles, pions, kaons, protons and antiprotons) are measured by the ALICE detector in p-Pb collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV in the transverse-momentum range 0.3<pT<4 GeV/c. The correlations expressed as associated yield per trigger particle are obtained in the pseudorapidity range |\u3b7lab|<0.8. Fourier coefficients are extracted from the long-range correlations projected onto the azimuthal angle difference and studied as a function of pT and in intervals of event multiplicity. In high-multiplicity events, the second-order coefficient for protons, v2p, is observed to be smaller than that for pions, v2\u3c0, up to about pT=2 GeV/c. To reduce correlations due to jets, the per-trigger yield measured in low-multiplicity events is subtracted from that in high-multiplicity events. A two-ridge structure is obtained for all particle species. The Fourier decomposition of this structure shows that the second-order coefficients for pions and kaons are similar. The v2p is found to be smaller at low pT and larger at higher pT than v2\u3c0, with a crossing occurring at about 2 GeV/c. This is qualitatively similar to the elliptic-flow pattern observed in heavy-ion collisions. A mass ordering effect at low transverse momenta is consistent with expectations from hydrodynamic model calculations assuming a collectively expanding system

Relationship between the mineralogical composition of the clay fraction of some andalusian caracteristic soils and theri behaviour in relation to potassium

12 páginas, 7 figuras, 3 tablas, 7 referencias.[ES]: Se estudia la fracción arcilla de los suelos más característicos de nuestra región y su comportamiento frente al potasio, relacionándolo con la composición mineralógica de dicha fracción. Exceptuando el suelo fersialítico, los diferentes horizontes de cada suelo no presentan variaciones importantes en su comportamiento frente al potasio. Los suelos vérticos litomorfos y vérticos topomorfos presentan los valores más altos de Kx, lo que está de acuerdo con una mayor edafización y con altas concentraciones de montmorillonita e ilita. El suelo calcimorfo, a pesar de poseer composición mineralógica simlar, está muy poco evolucionado y presenta valores más bajos de Kx, similares a los del suelo aluvial, que está asimismo poco evolucionado, con alta proporción de ilita, a la que acompañan pequeñas proporciones de montmorillonita y caolinita. En el suelo fersialítico lavado disminuye el valor de Kx, al descender en el perfil, en el mismo sentido en que disminuye la ilita y aumenta la montmorillonita. Los horizontes C de los suelos de gran desarrollo edafogenético presentan en relación con los horizontes superiores, a pesar de poseer composición mineralógica similar, valores muy pequeños de Kx. El grado de desarrollo del suelo es el que tiene mayor influencia en los valores de Kx. Los tratamientos de eliminación de materia orgánica y/o geles producen un aumento muy apreciable de los valores de Kx.[EN]: The clay fractions of soils caracteristic of western Anclalucía and their behaviour in relation to potassium are studied, and the latter in related to the mineralogical composition of the former. Except the "fersialitico soil" (Rhocloxeralfs), the various horizons of each soil do not present distinct variations in their behaviour in relation to potassium. The "vertisol litomorfo" (chromoxererts) and «topomorfo» (Pelloxererts) soils present the highest values of Kx which agrees with the strong weathering of these soils and their nigh proportions of montmoillonite and illite. The "calcimorfo soil" (Calciorthids) is little weathered and present lower values of Kx, despite its mineralogical composition, which is analogous to the preceding soils. Similarly low values of Kx are obtained for the «aluvial soil» (Xerofluvents), also little weathered, which contains high proportion of illite, with small amounts of montmorillonite and kaolinite. The value of Kx and the proportion of illite for the leached fersialitico soil decrease and the proportion of montmorillonite increases as getting down across the profile. C horizons of soils with high podogenic development present much lower values of Kx than upper horizona, despite the analogy of their mineralogical compositions. The degree of development of soils has the highest influence on Kx, values. Treatments for removing organic matter and/or gels originate important increases in Kx values.Peer reviewe

Measurement of charm production at central rapidity in proton-proton collisions at 1as = 2.76 TeV

The p t-differential production cross sections of the prompt (B feed-down subtracted) charmed mesons D0, D+, and D*+ in the rapidity range |y| &lt; 0.5, and for transverse momentum 1 &lt; p t &lt; 12 GeV/c, were measured in proton-proton collisions at 1as = 2.76 TeV with the ALICE detector at the Large Hadron Collider. The analysis exploited the hadronic decays D 0 \u2192 K -\u3c0 +, D + \u2192 K -\u3c0 +\u3c0 +, D *+ \u2192 D 0\u3c0 +, and their charge conjugates, and was performed on a L int = 1.1 nb -1 event sample collected in 2011 with a minimum-bias trigger. The total charm production cross section at 1as = 2.76 TeV and at 7 TeV was evaluated by extrapolating to the full phase space the p t-differential production cross sections at 1as = 2.76 TeV and our previous measurements at 1as = 7 TeV. The results were compared to existing measurements and to perturbative-QCD calculations. The fraction of cd D mesons produced in a vector state was also determined. \ua9 2012 SISSA

Measurement of visible cross sections in proton-lead collisions at 1asNN= 5.02 TeV in van der Meer scans with the ALICE detector

In 2013, the Large Hadron Collider provided proton-lead and lead-proton collisions at the center-of-mass energy per nucleon pair root s NN=5.02 TeV . Van der Meer scans were performed for both configurations of colliding beams, and the cross section was measured for two reference processes, based on particle detection by the T0 and V0 detectors, with pseudo-rapidity coverage 4.6 < \u3b7 < 4.9, -3.3 < \u3b7 < -3.0 and 2.8 < \u3b7 < 5.1, -3.7 < \u3b7 < -1.7, respectively. Given the asymmetric detector acceptance, the cross section was measured separately for the two configurations. The measured visible cross sections are used to calculate the integrated luminosity of the proton-lead and lead-proton data samples, and to indirectly measure the cross section for a third, configuration-independent, reference process, based on neutron detection by the Zero Degree Calorimeters

J/\u3a8 production and nuclear effects in p-Pb collisions at 1asNN=5.02 TeV

Inclusive J/\u3a8 production has been studied with the ALICE detector in p-Pb collisions at the nucleon-nucleon center of mass energy 1asNN = 5.02TeV at the CERN LHC. The measurement is performed in the center of mass rapidity domains 2.03 < ycms < 3.53 and ?4.46 < ycms < ?2.96, down to zero transverse momentum, studying the \u3bc+\u3bc? decay mode. In this paper, the J/\u3a8 production cross section and the nuclear modification factor RpPb for the rapidities under study are presented. While at forward rapidity, corresponding to the proton direction, a suppression of the J/\u3a8 yield with respect to binary-scaled pp collisions is observed, in the backward region no suppression is present. The ratio of the forward and backward yields is also measured differentially in rapidity and transverse momentum. Theoretical predictions based on nuclear shadowing, as well as on models including, in addition, a contribution from partonic energy loss, are in fair agreement with the experimental results

Centrality dependence of the pseudorapidity density distribution for charged particles in Pb\u2013Pb collisions at 1asNN = 2.76 TeV

We present the first wide-range measurement of the charged-particle pseudorapidity density distribution, for different centralities (the 0\u20135%, 5\u201310%, 10\u201320%, and 20\u201330% most central events) in Pb\u2013Pb collisions at 1asNN = 2.76 TeV at the LHC. The measurement is performed using the full coverage of the ALICE detectors, 125.0 < \u3b7 < 5.5, and employing a special analysis technique based on collisions arising from LHC \u2018satellite\u2019 bunches. We present the pseudorapidity density as a function of the number of participating nucleons as well as an extrapolation to the total number of produced charged particles (Nch = 17 165 \ub1 772 for the 0\u20135% most central collisions). From the measured dNch/d\u3b7 distribution we derive the rapidity density distribution, dNch/dy, under simple assumptions. The rapidity density distribution is found to be significantly wider than the predictions of the Landau model. We assess the validity of longitudinal scaling by comparing to lower energy results from RHIC. Finally the mechanisms of the underlying particle production are discussed based on a comparison with various theoretical models