• Energy Research

The outreach program “A scuola di Astroparticelle” was proposed in 2016 by the National Institute for Nuclear Physics (INFN - Napoli Division) in collaboration with the Physics Department “Ettore Pancini” of the Federico II University in Napoli, CNR-SPIN and CNR-ISASI Institutes. Its main goal is to engage teachers and students of High Schools in astroparticle physics projects. For the third edition (2018/19), the activities, which are also part of the Italian Educational Program PCTO - “Percorsi per le Competenze Trasversali e per l'Orientamento”, involved 18 schools for a total of 21 projects on several topics. Some projects were strictly related to astroparticles as cosmic rays, while others were more technical, as the development of particle detectors, or cross-disciplinary projects. Students worked for the entire school year and prepared materials for the final event. More than 600 students attended the event and presented their work to a jury with a poster and an oral presentation in plenary sessions. Since 2018, the program is part of OCRA - Outreach Cosmic Ray Activities - a national outreach project of INFN with the aim of collecting, within a common framework, the numerous outreach activities in cosmic-ray field carried out at the local level. The fourth edition (2019-20), in spite of the difficult situation due to the COVID-19 pandemic, has also seen the participation of 22 schools that carried out part of the activities in an online format. The project realized using the open data of the Pierre Auger Observatory will be presented in detail.

AbstractIn this paper, we report the measurement of the energy flow, the cross section and the average inelasticity of forward neutrons (+ antineutrons) produced in$$ \sqrt{s} $$s= 13 TeV proton-proton collisions. These quantities are obtained from the inclusive differential production cross section, measured using the LHCf Arm2 detector at the CERN Large Hadron Collider. The measurements are performed in six pseudorapidity regions: three of them (η >10.75, 8.99< η <9.21 and 8.80< η <8.99), albeit with smaller acceptance and larger uncertainties, were already published in a previous work, whereas the remaining three (10.06< η <10.75, 9.65< η <10.06 and 8.65< η <8.80) are presented here for the first time. The analysis was carried out using a data set acquired in June 2015 with a corresponding integrated luminosity of 0.194 nb−1. Comparing the experimental measurements with the expectations of several hadronic interaction models used to simulate cosmic ray air showers, none of these generators resulted to have a satisfactory agreement in all the phase space selected for the analysis. The inclusive differential production cross section forη >10.75 is not reproduced by any model, whereas the results still indicate a significant but less serious deviation at lower pseudorapidities. Depending on the pseudorapidity region, the generators showing the best overall agreement with data are either SIBYLL 2.3 or EPOS-LHC. Furthermore, apart from the most forward region, the derived energy flow and cross section distributions are best reproduced by EPOS-LHC. Finally, even if none of the models describe the elasticity distribution in a satisfactory way, the extracted average inelasticity is consistent with the QGSJET II-04 value, while most of the other generators give values that lie just outside the experimental uncertainties.

The main aim of the LHCf experiment is to provide precise measurements of the production spectra relative to neutral particles produced in the very forward region by high energy proton-proton and proton-ion collisions. This information is necessary in order to test and tune hadronic interaction models used by ground-based cosmic rays experiments. In order to reach this goal, LHCf makes use of two small sampling calorimeters installed in the LHC tunnel at $\pm 140$ m from IP1, able to detect neutral particles having pseudo-rapidity $\eta > 8.4$. After the operations relative to p-p collisions at $\mathrm{\sqrt{s} = 13~TeV}$, the collaboration focused the activity on the study of forward photons and neutrons production at this energy. In this paper, we discuss the recent results relative to the photons analysis, regarding, in particular, the inclusive production cross section, the role of diffractive and non-diffractive processes in forward photons production (investigated thanks to the LHCf-ATLAS joint analysis) and the forward differential energy flow.

Abstract In this paper, we report the measurement relative to the production of forward neutrons in proton-proton collisions at $$ \sqrt{s}=13 $$ s = 13 TeV obtained using the LHCf Arm2 detector at the Large Hadron Collider. The results for the inclusive differential production cross section are presented as a function of energy in three different pseudorapidity regions: η > 10.76, 8.99 < η < 9.22 and 8.81 < η < 8.99. The analysis was performed using a data set acquired in June 2015 that corresponds to an integrated luminosity of 0.194 nb−1. The measurements were compared with the predictions of several hadronic interaction models used to simulate air showers generated by Ultra High Energy Cosmic Rays. None of these generators showed good agreement with the data for all pseudorapidity intervals. For η > 10.76, no model is able to reproduce the observed peak structure at around 5 TeV and all models underestimate the total production cross section: among them, QGSJET II-04 shows the smallest deficit with respect to data for the whole energy range. For 8.99 < η < 9.22 and 8.81 < η < 8.99, the models having the best overall agreement with data are SIBYLL 2.3 and EPOS-LHC, respectively: in particular, in both regions SIBYLL 2.3 is able to reproduce the observed peak structure at around 1.5–2.5 TeV.

International audience The LHCf experiment is an LHC experiment dedicated to measure the production spectra of forward neutral particles, photons, \(\pi ^{0}\)s and neutrons. The obtained results are very useful to test hadronic interaction models which are used in MC simulations for cosmic-ray air shower developments. The LHCf had an operation in 2015 with p–p collisions at \(\sqrt{s} \) = 13 TeV, which corresponds to the collision energy of 0.9 × 10^17 eV in the laboratory frame. We discuss the results of the inclusive energy spectra for forward photons obtained at p–p, \(\sqrt{s} \) = 13 TeV data as well as \(\pi ^{0}\) results taken at p–p, \(\sqrt{s} \) = 7 TeV. In addition we introduce future prospects of LHCf analyses and activities.