Search

The Large Hadron Collider forward and the Relativistic Heavy Ion Collider forward experiments measured forward particles produced in high-energy hadron collisions at the LHC and RHIC. Using compact calorimeters neutral particles produced in pseudorapidities η >8.4 and η >6.0 are observed by the respective experiments. Because the collision energies ranging from 0.51 TeV to 13 TeV correspond to the cosmic-ray equivalent energies of 1014 to 1017 eV, the measurements are important to understand the hadronic interaction relevant to extensive air shower measurements. This paper reviews recent results of LHCf and initial performance of RHICf that took data in the 2017 RHIC operation.

The Large Hadron Collider is intensively used to test hadronic interaction models used in cosmic-ray physics because its maximum (designed) collision energy √s = 14 TeV corresponds to the interaction of a 1017 eV cosmic-ray proton hitting the atmosphere. In this paper various types of forward experiments at the LHC, where the particles relevant to the air shower development are observed, are reviewed. Recent results of a dedicated experiment for precise forward measurement, the LHC forward, are discussed in detail. A future possibility at the LHC, light ion collisions, is also discussed.

The LHCf experiment, optimized for the study of forward physics at LHC, completes its main physics program in this year 2015, with the proton-proton collisions at the energy of 13 TeV. LHCf gives important results on the study of neutral particles at extreme pseudo-rapidity, both for proton-proton and for proton-ion interactions. These results are an important reference for tuning the models of the hadronic interaction currently used for the simulation of the atmospheric showers induced by very high energy cosmic rays. The results of this analysis and the future perspective are presented in this paper.

The LHCf experiment is one of the LHC forward experiments. The aim of LHCf is to provide critical calibration data of hadronic intraction models used in air shower simulations. The LHCf has completed the operations for p-p collisions with a collision energy of √s = 0.9 and 7 TeV p-p in 2010 and for p-Pb collisions with a collision energy per nucleon of √sNN = 5.02. The recent LHCf result of forward neutron energy spectra at 7 TeV p-p collision and forward π0 spectra at p-Pb collisions are presented in this paper.

The LHCf experiment is a CERN experiment dedicated to forward physics which is optimized to measure the neutral particle flow at extreme pseudo-rapidity values, ranging from 8.4 up to infinity. LHCf results are extremely important for the calibration of the hadronic interaction models used for the study of the development of atmospheric showers in the Earth atmosphere. Starting from the recent run of proton-Lead nucleus interactions at LHC, the LHCf and ATLAS collaborations have performed a common data taking which allows a combined study of the central and forward regions of the interaction. The latest results of LHCf, the upgrade of the detectors for the next 6.5 TeV + 6.5 TeV proton–proton run and the status of the LHCf-ATLAS common activities are summarized in this paper.

LHCf is a small detector installed at LHC accelerator to measure neutral particle flow in the forward direction of proton -proton (p - p) and proton -nucleus (p - A) interactions. Thanks to the optimal performance that has characterized the last years’ running of the LHC collider, several measurements have been taken since 2009 in different running conditions. After data taking for p - p interactions at √s = 900 GeV, 2.76 TeV and 7 TeV and proton - Lead nucleus (p -Pb) at √sNN = 5.02 TeV (energy of a couple of projectile and target nucleons in their center of mass reference frame), LHCf is now going to complete its physics program with the 13 TeV p - p run foreseen in 2015. The complete set of results will become a reference data set of forward physics for the calibration and tuning of the hadronic interaction models currently used for the simulation of the atmospheric showers induced by very high energy cosmic rays. For this reason we think that LHCf is giving an important contribution for the study of cosmic rays at the highest energies. In this paper the experiment, the published results and the current status are reviewed.

LHCf is planning to measure very forward particle emission in the LHC p-Pb collisions foreseen at the end of 2012. The measurement is expected to constrain the nuclear effect in the forward particle emission relevant to the CR-Air interaction. Model discrimination power of this measurement is presented together with some detail in technical feasibility.

The Large Hadron Collider forward (= LHCf) experiment has successfully finished the first phase of data taking at LHC √s = 0.9 and 7 TeV proton-proton collisions in 2010. As current status, we concentrate on analyzing the obtained data. As the first result, the energy spectra of photon measured by LHCf during = 7 TeV p-p collision has been published recently. Also the study of the upgraded version of LHCf detector for future = 14TeV run scenario is developed with the GSO scintillator. Another possible plan of p-A(nuclear) collision in LHC is also studied. In this paper, as the current status of the experiment, analyses, and works for foreseen detector upgrade are summarized.