J. Velasco
Spanish National Research Council
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Featured researches published by J. Velasco.
Physics Letters B | 2011
O. Adriani; L. Bonechi; M. Bongi; G. Castellini; Raffaello D'Alessandro; A. Faus; K. Fukatsu; M. Haguenauer; Y. Itow; K. Kasahara; Kentaro Kawade; D. Macina; T. Mase; K. Masuda; Y. Matsubara; H. Menjo; G. Mitsuka; Y. Muraki; M. Nakai; K. Noda; P. Papini; A. L. Perrot; S. B. Ricciarini; T. Sako; Y. Shimizu; K. Suzuki; T. Suzuki; K. Taki; T. Tamura; S. Torii
Abstract In early 2010, the Large Hadron Collider forward (LHCf) experiment measured very forward neutral particle spectra in LHC proton–proton collisions. From a limited data set taken under the best beam conditions (low beam-gas background and low occurrence of pile-up events), the single photon spectra at s = 7 TeV and pseudo-rapidity (η) ranges from 8.81 to 8.99 and from 10.94 to infinity were obtained for the first time and are reported in this Letter. The spectra from two independent LHCf detectors are consistent with one another and serve as a cross check of the data. The photon spectra are also compared with the predictions of several hadron interaction models that are used extensively for modeling ultra-high energy cosmic-ray showers. Despite conservative estimates for the systematic errors, none of the models agree perfectly with the measurements. A notable difference is found between the data and the DPMJET 3.04 and PYTHIA 8.145 hadron interaction models above 2 TeV where the models predict higher photon yield than the data. The QGSJET II-03 model predicts overall lower photon yield than the data, especially above 2 TeV in the rapidity range 8.81 η 8.99 .
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment | 1989
P. Checchia; G. Galeazzi; U. Gasparini; I. Lippi; M. Mazzucato; M. Pegoraro; C. Pinori; F. Simonetto; L. Ventura; G. Zumerle; A. Lopez; J. Marco; A. Ruiz; F. Bianchi; R. Cirio; D. Gamba; E. Menichetti; G. Rinaudo; A. Romero; E. Castelli; L. Lanceri; P. Poropat; R. Ragazzon; M. Sessa; A. De Angelis; F. Scuri; F. Waldner; A. Ferrer; J.J. Gomez; A. Sebastia
Abstract We present the performance of the DELPHI lead glass calorimeter with vacuum phototriode readout. The behaviour of the counters in magnetic fields up to 1.1 T is discussed. Experimental results, obtained with an electron beam from 7 to 50 GeV/c, on noise, linearity, energy and position resolution are presented.
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment | 1986
P. Checchia; G. Galeazzi; U. Gasparini; M. Mazzucato; M. Pegoraro; L. Ventura; G. Zumerle; A. Lopez; F. Bianchi; E. Menichetti; A. Romero; S. Rustichelli; E. Castelli; L. Lanceri; P. Poropat; A. Ferrer; J.J. Gomez; J. Velasco
Abstract A prototype calorimeter of lead glass bars read by one-stage vacuum photomultipliers (triodes) has been tested at CERN with electrons in the energy range 2–30 GeV. Different glass-triode combinations have been compared. An electronic amplification noise corresponding to about 30 MeV has been obtained. The space resolution has been measured to be 4.4 mm on average.
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment | 1989
F. Bianchi; E. Castelli; P. Checchia; R. Cirio; Mp Clara; A. De Angelis; A. Ferrer; G. Galeazzi; D. Gamba; U. Gasparini; M Innocente; L. Lanceri; I Lippi; A. Lopez; J. Marco; Caridad Martinez; Mirco Mazzucato; E Menichetti; M Pegoraro; C. Pinori; P. Poropat; R. Ragazzon; G Rinaudo; Alessandra Romero; P. Ronchese; A. Ruiz; F. Scuri; A. Sebastia; M. Sessa; F. Simonetto
Abstract As a part of a large experimental program aiming to produce high quality calibration data for the Forward ElectroMagnetic Calorimeter (FEMC) of the DELPHI detector at LEP, special runs were devoted to the study of the transverse profile of electromagnetic showers in lead glass. Results of this study are presented.
Nuclear Physics | 2011
O. Adriani; L. Bonechi; M. Bongi; G. Castellini; R. D'Alessandro; A. Faus; K. Fukatsu; M. Haguenauer; Y. Itow; K. Kasahara; D. Macina; T. Mase; K. Masuda; Y. Matsubara; H. Menjo; G. Mitsuka; Y. Muraki; M. Nakai; K. Noda; P. Papini; A. L. Perrot; S. B. Ricciarini; T. K. Sako; K. Suzuki; T. Suzuki; Y. Shimizu; K. Taki; T. Tamura; S. Torii; A. Tricomi
LHCf is an experiment dedicated to the measurement of neutral particles emitted in the very forward region of LHC collisions. The physics goal is to provide data for calibrating hadron interaction models that are used in the study of Extremely High-Energy Cosmic-Rays. The LHCf experiment acquired data from April to July 2010 during commissioning time of LHC operations at low luminosity. Production spectra of photons and neutrons emitted in the very forward region (
Journal of the Physical Society of Japan | 2009
M. Mizuishi; O. Adriani; L. Boneohi; M. Bongi; G. Castellini; Raffaello D'Alessandro; D. A. Faus; K. Fukui; M. Grandi; Maurice Haguenauer; Y. Itow; K. Kasahara; D. Macina; T. Mase; K. Masuda; Y. Matsubara; H. Menjo; Y. Muraki; P. Papini; A. L. Perrot; S. B. Ricciarini; T. Sako; Y. Shimizu; K. Taki; T. Tamura; S. Torii; A. Tricomi; W. C. Turner; J. Velasco; A. Viciani
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Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment | 1987
J.J. Gomez; J. Velasco; E. Maestro
8.4) have been obtained. In this paper preliminary results of the photon spectra taken at
Journal of the Physical Society of Japan | 2009
O. Adriani; L. Bonechi; M. Bongi; G. Castellini; [No Value] RD'Alessandro; D. A. Faus; K. Fukui; Maurice Haguenauer; Y. Itow; K. Kasahara; D. Macina; T. Mase; K. Masuda; Y. Matsubara; H. Menjo; M. Mizuishi; Y. Muraki; P. Papini; A. L. Perrot; S. B. Ricciarini; T. Sako; Y. Shimizu; K. Taki; T. Tamura; S. Torii; A. Tricomi; W. C. Turner; J. Velasco; A. Viciani; H. Watanabe
\sqrt{s}
Journal of Physics: Conference Series | 2008
A. Tricomi; O. Adriani; L. Bonechi; M. Bongi; G. Castellini; R. D'Alessandro; A. Faus; K. Fukui; M. Haguenauer; Y. Itow; K. Kasahara; D. Macina; T. Mase; K. Masuda; Y. Matsubara; M. Mizuishi; H. Menjo; Y. Muraki; P. Papini; A. L. Perrot; S. B. Ricciarini; T. Sako; Yuki Shimizu; T. Tamura; K. Taki; S. Torii; W. C. Turner; J. Velasco; H. Watanabe; K. Yoshida
= 7TeV are reported.
Proceedings of The 34th International Cosmic Ray Conference — PoS(ICRC2015) | 2016
H. Menjo; O. Adriani; L. Bonechi; M. Bongi; G. Castellini; R. D'Alessandro; D. A. Faus; K. Fukui; M. Haguenauer; Y. Itow; K. Kasahara; D. Macina; T. Mase; K. Masuda; Y. Matsubara; H. Matsumoto; M. Mizuishi; Y. Muraki; P. Papini; A. L. Perrot; T. Sako; Y. Shimizu; T. Tamura; K. Taki; S. Torii; A. Tricomi; W. C. Turner; J. Velasco; H. Watanabe; K. Yoshida
The Large Hadron Collider forward (LHCf) experiment will provide the energy and transverse momentum spectra of neutral particles produced in the very forward region of p-p collision at 7+7 TeV, corresponding to a laboratory frame energy of 10 17 eV. The LHCf apparatus is composed of two independent detectors installed at zero degree collision angle from the ATLAS interaction point. To assess performance of LHCf detectors, we carried out a beam test in 2007 at the CERN SPS H4 beamline. We report results of the Arm#1 detector, using scintillating fibers for measuring shower positions, obtained from electron primary beams of 50–200 GeV, and proton primary beams of 150–350 GeV and muon primary beams of 150–200 GeV. We obtained energy resolution of electrons as a function of the primary energy . The position resolution of shower axis is obtained by using a position determined with the Si microstrip detectors. We also reconstructed the real geometry of each SciFi by the use of muon primary beams. Finally, we re...
