Muon deficit in simulations of air showers inferred from AGASA data

Multiple experiments reported evidences of a muon deficit in air shower simulations with respect to data, which increases with the primary energy. In this work, we study the muon deficit using measurements of the muon density at 1000 m from the shower axis obtained by the Akeno Giant Air Shower Array (AGASA). The selected events have reconstructed energies in the range $18.83\,\leq\,\log_{10}(E_{R}/\textrm{eV})\,\leq\,19.46$ and zenith angles $\theta\leq 36^{\circ}$. We compare these muon density measurements to proton, iron, and mixed composition scenarios, obtained by using the high-energy hadronic interaction models EPOS-LHC, QGSJetII-04, and Sibyll2.3c. We find that AGASA data are compatible with a heavier composition, lying above the predictions of the mixed composition scenarios. The average muon density divided by the energy in AGASA data is greater than in the mixed composition scenarios by a factor of $1.49\pm0.11\,\textrm{(stat)}\pm^{0.49}_{0.30}\,\textrm{(syst)}$, $1.54\pm0.12\,\textrm{(stat)}\pm^{0.50}_{0.31}\,\textrm{(syst)}$, and $1.66\pm0.13\,\textrm{(stat)} \pm ^{0.54}_{0.34}\,\textrm{(syst)}$ for EPOS-LHC, Sibyll2.3c, and QGSJetII-04, respectively. We interpret this as further evidence of a muon deficit in air shower simulations at the highest energies

Mental Health and Coaching Challenges Facing the COVID-19 Outbreak

On 31th December 2019 an increasing number of pneumonia of unknown aetiology that depend on a new virus, SarsCoV-2, has been registered. The epicentre of the spread of the pathogen has been identified in the Chinese city of Wuhan, but the Coronavirus has reached other neighbouring countries and on January 24th the first cases have been ascertained in Europe, until the World Health Organization declared the state of pandemic. Coaching can be the key to find oneself and therefore to focus more effectively on the actual bonds, affections and investments, at least slightly reducing the need for elsewhere that often characterizes the escape from oneself. In our experience, coaching can stimulate and promote the growth and improvement of personal resources and the potential of each individual in full respect of their uniqueness and their peculiar characteristics, helping to revive the ability to think and dream of a better future. Specifically, in this particularly delicate moment, embarking on a coaching process can make learn resilience, acquire specific skills and discover transversal abilities. Coaching can offer the opportunity to find the motivation and perseverance to adopt functional behaviours to achieve a greater level of well-being. The coaching process can transform this moment of crisis into an opportunity for personal and professional growth, facing uncertainty and change, keeping the course and focus on own objectives, investing to improve himself. The construction of an ethics of collaboration and solidarity, in which everyone renounces something in the name of the common good could be the best way to look forward to the future with less anxiety and to preserve mental and physical health

Air shower genealogy for muon production

Measurements of the muon content of extensive air showers at the highest energies show discrepancies compared to simulations as large as the differences between proton and iron. This so-called muon puzzle is commonly attributed to a lack of understanding of the hadronic interactions in the shower development. Furthermore, measurements of the fluctuations of muon numbers suggest that the discrepancy is likely a cumulative effect of interactions of all energies in the cascade. A feature of the air shower simulation code CORSIKA 8 allows us to access all previous generations of final-state muons up to the first interaction. With this technique, we study the influence of interactions happening at any intermediate stage in the cascade on muons depending on their lateral distance in a quantitative way and compare our results with predictions of the Heitler-Matthews model.Comment: 8 pages, 4 figures, proceedings of the 37th International Cosmic Ray Conference (ICRC 2021); v2: references update

Muon deficit in simulations of air showers inferred from AGASA data

Multiple experiments reported evidences of a muon deficit in air shower simulations with respect to data, which increases with the primary energy. In this work, we study the muon deficit using measurements of the muon density at 1000 m from the shower axis obtained by the Akeno Giant Air Shower Array (AGASA). The selected events have reconstructed energies in the range $18.83\,\leq\,\log_{10}(E_{R}/\textrm{eV})\,\leq\,19.46$ and zenith angles $\theta\leq 36^{\circ}$. We compare these muon density measurements to proton, iron, and mixed composition scenarios, obtained by using the high-energy hadronic interaction models EPOS-LHC, QGSJetII-04, and Sibyll2.3c. We find that AGASA data are compatible with a heavier composition, lying above the predictions of the mixed composition scenarios. The average muon density divided by the energy in AGASA data is greater than in the mixed composition scenarios by a factor of $1.49\pm0.11\,\textrm{(stat)}\pm^{0.49}_{0.30}\,\textrm{(syst)}$, $1.54\pm0.12\,\textrm{(stat)}\pm^{0.50}_{0.31}\,\textrm{(syst)}$, and $1.66\pm0.13\,\textrm{(stat)} \pm ^{0.54}_{0.34}\,\textrm{(syst)}$ for EPOS-LHC, Sibyll2.3c, and QGSJetII-04, respectively. We interpret this as further evidence of a muon deficit in air shower simulations at the highest energies

Air shower genealogy for muon production

Measurements of the muon content of extensive air showers at the highest energies show discrepancies compared to simulations as large as the differences between proton and iron. This so-called muon puzzle is commonly attributed to a lack of understanding of the hadronic interactions in the shower development. Furthermore, measurements of the fluctuations of muon numbers suggest that the discrepancy is likely a cumulative effect of interactions of all energies in the cascade. A feature of the air shower simulation code CORSIKA 8 allows us to access all previous generations of final-state muons up to the first interaction. With this technique, we study the influence of interactions happening at any intermediate stage in the cascade on muons depending on their lateral distance in a quantitative way and compare our results with predictions of the Heitler-Matthews model.Comment: 8 pages, 4 figures, proceedings of the 37th International Cosmic Ray Conference (ICRC 2021); v2: references update

On the muon scale of air showers and its application to the AGASA data

Recently, several experiments reported a muon deficit in air shower simulations with respect to the data. This problem can be studied using an estimator that quantifies the relative muon content of the data with respect to those of proton and iron Monte Carlo air shower simulations. We analyze two estimators. The first one, based on the logarithm of the mean of the muon content, is built from experimental considerations. It is ideal for comparing results from different experiments as it is independent of the detector resolution. The second estimator is based on the mean of the logarithm of the muon content, which implies that it depends on shower-to-shower fluctuations. It is linked to the mean-logarithmic mass $⟨ln A⟩$ through the Heitler-Matthews model. We study the properties of the estimators and their biases considering the knowns and unknowns of typical experiments. Furthermore, we study these effects in measurements of the muon density at 1000m from the shower axis obtained by the Akeno Giant Air Shower Array (AGASA). Finally, we report the estimates of the relative muon content of the AGASA data, which support a muon deficit in simulations. These estimates constitute valuable additional information of the muon content of air showers at the highest energies

Indications for flexible fiberoptic bronchoscopy and its safety in the very elderly

Aim. To evaluate the indications and the safety of fiberoptic bronchoscopy (FOB) with bronchoalveolar lavage (BAL), protected specimen brushing (PSB), endobronchial biopsy (EBB), and transbronchial biopsy (TBB) in a population of very elderly patients. Methods. We performed a retrospective study of all adult patients, aged 50 years or older, who underwent FOB in the Bronchology Unit of the University of Parma Hospital between 1 January, 2003 and 31 April, 2005. Bronchoscopy records of 436 consecutive patients, including 191 patients, 75 yrs of age and older ("very elderly"; =>75 yrs), were reviewed. Results. Patients aged 75 years were no different with regard to gender, BMI, baseline FEV1/FVC ratio, baseline SaO2, and blood pressure. The primary indication in patients aged <75 years, was to assist in the diagnosis of a pulmonary mass of unknown aetiology (33%) and to remove secretions in the very elderly patients (31%). Indications for FOB and sampling procedures in the two groups were similar. Approximately 30% of patients in each group required supplemental oxygen during the procedure and fever occurred in 9.2% and 10.3% of patients, respectively.Hypertension and bleeding were relatively rare and did not occur more often in the very elderly. Conclusions. Indication for FOB did not vary with age and adverse events in both groups were uncommon and generally not severe

Zenith-Angular Characteristics of Particles in EASs with E0≃1018E_0 \simeq 10^{18} eV According to the Yakutsk Array Data

Particle lateral distributions were investigated in cosmic ray air showers with energy $E_0 \simeq 10^{18}$ eV registered at the Yakutsk array with surface and underground scintillation detectors with $\simeq 1 \times \sec\theta$~GeV threshold during the period of continuous observations from 1986 to 2016. The analysis covers events with arrival direction zenith angles $\theta \le 60^{\circ}$ within five intervals with step $\Delta\cos\theta = 0.1$. Experimental values were compared to simulation results obtained with the use of CORSIKA code within the framework of QGSJet01 hadron interaction model. The whole dataset points at probable cosmic ray composition which is close to protons.Comment: 14 pages, 6 figures. Accepted for publication in Physics of Atomic Nuclei, volume 86 (2023

The muon content of atmospheric air showers and the mass composition of cosmic rays

Cosmic rays are messengers from outer space holding the answer to the Universe\u27s deepest mysteries: What are they exactly? Where do they come from? How do they accelerate to such energies, and how are the laws governing their interactions? At the highest energies, these unubiquitous particles can only be detected through the showers of secondary particles that they generate in their interactions with the Earth\u27s atmosphere. Large ground-based observatories, like the Pierre Auger Observatory, detect these extensive air showers and attempt to reconstruct as much information of the primary cosmic ray as possible. In particular, the number of secondary muons is a key observable because it is directly related to the atomic mass number of the primary that generated them. Understanding the mass composition as a function of the energy would shed light on various open questions strongly linked to the origin of cosmic rays. The Pierre Auger Observatory has dedicated scintillators buried underground to directly detect muons, the Underground Muon Detector (UMD). This thesis is devoted to the accurate determination of the muon content of air showers and to the study of its composition implications. We analyze direct muon measurements of air showers with energies between $10^{17.22}\,$eV and $10^{19.46}\,$eV from two experiments. At lower energies we extensively analyze UMD data, which we complement at higher energies with measurements from the Akeno Giant Air Shower Array (AGASA). For the UMD data, we develop new methods that significantly improve the estimation of the muon number. These methods also allow for the reconstruction of the muon signal as a function of time with an unprecedented time resolution, opening the door to the reconstruction of new composition-sensitive observables. As a direct application, we study the measured lateral distribution of muons and the models that attempt to describe it. Furthermore, we analyze the mass composition implications of the UMD and AGASA data. The composition interpretation of the data can only be inferred by a comparison against air-shower simulations. We therefore simulate single-proton, single-iron, and mixed composition scenarios based on the three newest-generation high-energy hadronic interaction models. To better compare the results against those of other experiments, we compute the so called $z$-values, a scale of the muon content in data relative to that of proton and iron simulations. The combined results offer a picture consistent with other experiments: the unexpectedly heavy composition constitutes evidence of a muon deficit in air-shower simulations that increases with the energy. These results can help to improve the high-energy hadronic interaction models, which in turn would improve the precision of the inferred mass composition