Showing papers by "German Martinez published in 2003"

Elliptic flow of identified hadrons in [formula presented] collisions at [formula presented]

Abstract: The anisotropy parameter (v(2)), the second harmonic of the azimuthal particle distribution, has been measured with the PHENIX detector in Au+Au collisions at roots(NN)=200 GeV for identified and inclusive charged particle production at central rapidities (eta 2 GeV/c, in marked contrast to the predictions of a hydrodynamical model. A quark-coalescence model is also investigated.

Suppressed π0 Production at Large Transverse Momentum in Central Au + Au Collisions at √sNN = 200 GeV

Abstract: Transverse momentum spectra of neutral pions in the range 1 < p_T < 10 GeV/c have been measured at mid-rapidity by the PHENIX experiment at RHIC in Au+Au collisions at sqrt(s_NN) = 200 GeV. The pi^0 multiplicity in central reactions is significantly below the yields measured at the same sqrt(s_NN) in peripheral Au+Au and p+p reactions scaled by the number of nucleon-nucleon collisions. For the most central bin, the suppression factor is ~2.5 at p_T = 2 GeV/c and increases to ~4-5 at p_T ~= 4 GeV/c. At larger p_T, the suppression remains constant within errors. The deficit is already apparent in semi-peripheral reactions and increases smoothly with centrality.

PHENIX detector overview

Abstract: The PHENIX detector is designed to perform a broad study of A-A, p-A, and p-p collisions to investigate nuclear matter under extreme conditions A wide variety of probes, sensitive to all timescales, are used to study systematic variations with species and energy as well as to measure the spin structure of the nucleon Designing for the needs of the heavy-ion and polarized-proton programs has produced a detector with unparalleled capabilities PHENIX measures electron and muon pairs, photons, and hadrons with excellent energy and momentum resolution The detector consists of a large number of subsystems that are discussed in other papers in this volume The overall design parameters of the detector are presented (C) 2002 Elsevier Science BV All rights reserved

Suppressedπ0Production at Large Transverse Momentum in CentralAu+AuCollisions atsNN=200GeV

Abstract: Transverse momentum spectra of neutral pions in the range $1l{p}_{T}l10\text{ }\text{ }\mathrm{G}\mathrm{e}\mathrm{V}/c$ have been measured at midrapidity by the PHENIX experiment at BNL RHIC in $\mathrm{A}\mathrm{u}+\mathrm{A}\mathrm{u}$ collisions at $\sqrt{{s}_{NN}}=200\text{ }\text{ }\mathrm{G}\mathrm{e}\mathrm{V}$. The ${\ensuremath{\pi}}^{0}$ multiplicity in central reactions is significantly below the yields measured at the same $\sqrt{{s}_{NN}}$ in peripheral $\mathrm{A}\mathrm{u}+\mathrm{A}\mathrm{u}$ and $p+p$ reactions scaled by the number of nucleon-nucleon collisions. For the most central bin, the suppression factor is $\ensuremath{\sim}2.5$ at ${p}_{T}=2\text{ }\text{ }\mathrm{G}\mathrm{e}\mathrm{V}/c$ and increases to $\ensuremath{\sim}4--5$ at ${p}_{T}\ensuremath{\approx}4\text{ }\text{ }\mathrm{G}\mathrm{e}\mathrm{V}/c$. At larger ${p}_{T}$, the suppression remains constant within errors. The deficit is already apparent in semiperipheral reactions and increases smoothly with centrality.

Absence of suppression in particle production at large transverse momentum in √sNN = 200 GeV d + Au collisions

Abstract: Transverse momentum spectra of charged hadrons with p(T)<8 GeV/c and neutral pions with p(T)<10 GeV/c have been measured at midrapidity by the PHENIX experiment at BNL RHIC in d+Au collisions at sqrt[s(NN)]=200 GeV. The measured yields are compared to those in p+p collisions at the same sqrt[s(NN)] scaled up by the number of underlying nucleon-nucleon collisions in d+Au. The yield ratio does not show the suppression observed in central Au+Au collisions at RHIC. Instead, there is a small enhancement in the yield of high momentum particles.

Midrapidity Neutral-Pion Production in Proton-Proton Collisions at √s = 200 GeV

Abstract: The invariant differential cross section for inclusive neutral-pion production in p+p collisions at roots=200 GeV has been measured at midrapidity (eta<0.35) over the range 1

Scaling Properties of Proton and Antiproton Production in √S NN = 200 GeV Au + Au Collisions

Abstract: We report on the yield of protons and antiprotons, as a function of centrality and transverse momentum, in Au+Au collisions at rootS(NN)=200 GeV measured at midrapidity by the PHENIX experiment at the BNL Relativistic Heavy Ion Collider. In central collisions at intermediate transverse momenta (1.5

The AMS-02 RICH Imager Prototype - In-Beam Tests with 20 GeV/c per Nucleon Ions -

Abstract: A prototype of the AMS Cherenkov imager (RICH) has been tested at CERN by means of a low intensity 20 GeV/c per nucleon ion beam obtained by fragmentation of a primary beam of Pb ions. Data have been collected with a single beam setting, over the range of nuclear charges 2

The AMS-02 RICH Imager Prototype In-Beam Tests with 20 GeV/c per Nucleon Ions

Abstract: A prototype of the AMS Cherenkov imager (RICH) has been tested at CERN by means of a low intensity 20 GeV/c per nucleon ion beam obtained by fragmentation of a primary beam of Pb ions. Data have been collected with a single beam setting, over the range of nuclear charges 2

Las podas cuadrada y piramidal truncada, con y sin aserrado, en la producción del mango

Abstract: espanolEn el Centro Nacional de Investigaciones Agropecuarias del INIA, Maracay-Venezuela, se condujo un ensayo durante los ciclos de produccion 1999-2000 y 2000-2001, en arboles de mango en periodo de crecimiento, de los cvs. Haden, Tommy Atkins, Edward y Kent, injertados en "criollo", distanciados a 6 m entre si (278 plantas ha-1), para evaluar el efecto de la copa piramidal truncada, cuadrada y en libre crecimiento, con y sin aserrado de las ramas principales, sobre el desarrollo vegetativo, floracion y produccion. Los tratamientos fueron: testigo (T) plantas en libre crecimiento sin aserrado (TSA); T con aserrado (TCA); forma piramidal truncada con aserrado (FPTCA); FPT sin aserrado (FPTSA); forma cuadrada con aserrado (FCCA) y FC sin aserrado (FCSA). Las variables estudiadas fueron: incremento del volumen de copa (IVC), porcentaje de floracion, rendimiento (kg de frutos planta-1) y eficiencia productiva kg frutos (m3)-1. Se empleo un diseno completamente aleatorizado con un arreglo factorial (4x3x2), donde cada parcela estuvo constituida por un arbol, con cinco repeticiones por tratamiento por cultivar. Los resultados evidenciaron que a mayor remocion de follaje para la configuracion de la copa, mayor IVC, con reduccion de la floracion (%) y produccion de frutos. La eficiencia productiva de la FPT ocupo la primera posicion, y en el tiempo, acentuo su diferencia significativa en relacion con la FC y al T. El aserrado de las ramas principales no tuvo efectos significativo sobre las variables estudiadas. Los rendimientos (t ha-1) promedio para los dos ciclos de produccion fueron 19,29 T; 14,72 FC y 11,97 FPT. Los rendimientos de FPT y FC superan en 149% y 189%, respectivamente, a los alcanzados de 7,5-8,5 t ha' en huertos comerciales de la misma edad, 7 a 8 anos, en el sistema tradicional donde emplean 69 plantas ha-1. EnglishAn essay on mangoes was carried out by CENIAP-INIA (National Research Center for Agriculture) in Maracay, Venezuela, during production years of 1999-2000 and 2000-2001. Mango trees of cultivars Haden, Tommy Atkins, Edwards and Kent, grafted on "Criollo" that induces low height, spaced 6x6 m (278) pl ha-1) were evaluated during full growth period in order to study canopy effect of the shapes truncated pyramidal, square and free growth, with cortical cutting and without cortical cutting or ring-shaped of fifty percent of the main branches, over vegetative growth, flowering and production.Treatments were: control trees in free growth without cortical cutting (TSA), control trees in free growth with cortical cutting (TCA), truncated pyramidal shape without cortical cutting (FPTSA), truncated pyramidal shape with cortical cutting (FPTCA), square shape without cortical cutting (FCSA), square shape with cortical cutting (FCCA). Variables studied wee: increase of canopy volume (IVC), flowering percentage, yield (kg tree-1) and productive efficiency. A completely randomized design with five replications in a factorial arrangement (4x3x2) was used, having each tree represent a plot. Results revealed that as pruning increased so did IVC, with reduction of flowering and fruit yield. Productive efficiency of FPT was the highest of the essay, and over time in increased its difference in relation to FC and free growth (T). Cortical cutting did not show significant effect over the variables studied. Mean yields (t ha-1), for the two years of production, were: T 19.29, FC 14.72 and FPT 11.97; FPT and FC mean yields are 149% and 189% superior in relation to 7.5-8.5 t ha-1 of the traditional system of planting (69 pl ha-1), with orchards of similar age (seven to eight).