The Large Hadron Collider forward (LHCf) experiment is designed to use the LHC to verify the hadronic-interaction models used in cosmic-ray physics. Forward baryon production is one of the crucial ...points to understand the development of cosmic-ray showers. We report the neutron-energy spectra for LHC s=7 TeV proton–proton collisions with the pseudo-rapidity η ranging from 8.81 to 8.99, from 8.99 to 9.22, and from 10.76 to infinity. The measured energy spectra obtained from the two independent calorimeters of Arm1 and Arm2 show the same characteristic feature before unfolding the detector responses. We unfolded the measured spectra by using the multidimensional unfolding method based on Bayesian theory, and the unfolded spectra were compared with current hadronic-interaction models. The QGSJET II-03 model predicts a high neutron production rate at the highest pseudo-rapidity range similar to our results, and the DPMJET 3.04 model describes our results well at the lower pseudo-rapidity ranges. However, no model perfectly explains the experimental results over the entire pseudo-rapidity range. The experimental data indicate a more abundant neutron production rate relative to the photon production than any model predictions studied here.
SuperKEKB is an electron–positron asymmetric-energy double-ring collider, which was built in Japan. It has been operated to explore new phenomena in B-meson decays. Hence, extremely higher luminosity ...is required. A collision scheme of low emittance with a large Piwinski angle called a “nano-beam scheme” has been adopted to achieve higher luminosity by squeezing the vertical beta function at the interaction point to be smaller than the bunch length. A “crab waist collision scheme” proposed by P. Raimondi et al. has also been adopted to improve the luminosity performance. The article presents an overview of the operation of the nano-beam and crab waist collision schemes at SuperKEKB.
Energy resolution and linearity of the LHCf calorimeters for electromagnetic showers were measured at the SPS H4 beam line in 2007 using electron beams of 50–200GeV and muon beams of 150GeV. The ...absolute energy scale was determined in these data. The results that were obtained (<5% energy resolution) are well understood by using Monte Carlo simulations and are good enough for the requirements of the LHCf experiment.
LHCf Experiment: Physics Results Bongi, M.; Adriani, O.; Berti, E. ...
Nuclear and particle physics proceedings,
10/2016, Letnik:
279-281
Journal Article
Recenzirano
LHCf is an experiment designed to study the forward emission of neutral particles produced in proton-proton and proton-nucleus collisions at the LHC. The detectors consists of a pair of ...electromagnetic sampling calorimeters installed on both sides of the ATLAS interaction point IP1 at a distance of 140 m, covering the pseudorapidity range from 8.4 to infinity. The experiment has successfully measured the energy spectra of gamma rays, neutral pions and neutrons in p-p collisions at 0.9 TeV and 7 TeV, and of neutral pions in p-Pb collisions at 5.02 TeV and in p-p collisions at 2.76 TeV. The most recent data set has been acquired during a special physics run of p-p collisions at 13 TeV in June 2015 after the restart of the LHC. This set of measurements represent an useful contribution to the calibration and tuning of the hadronic interaction models used for the simulation of atmospheric showers induced by very-high energy cosmic rays, as the measured energy interval corresponds to the range 1014 - 1017 eV in the laboratory frame.
The LHCf experiment is one of the LHC forward experiments. The aim is to measure the energy and the transverse momentum spectra of photons, neutrons and pi 0 's at the very forward region (the ...pseudo-rapidity range of h > 8.4), which should be critical data to calibrate hadron interaction models used in the air shower simulations. LHCf successfully operated at s = 900 GeV and s = 7 TeV proton-proton collisions in 2009 and 2010. We present the first physics result, single photon energy spectra at s = 7 TeV proton-proton collisions and the pseudo-rapidity ranges of h > 10.94 and 8.81 < h < 8.9 . The obtained spectra were compared with the predictions by several hadron interaction models and the models do not reproduce the experimental results perfectly.
The LHCf experiment is dedicated to the measurement of very forward particle production in the high energy hadron-hadron collisions at LHC, with the aim of improving the cosmic-ray air shower ...developments models. The detector has taken data in p-p collisions at different center of mass energies, from 900 GeV up to 7 TeV, and in p-Pb collisions at s=5.02 TeV. The results of forward production spectra of neutrons in p-p collisions and π0 in p-Pb collisions, compared with the models most widely used in the High Energy Cosmic Ray physics, are presented in this paper.
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