In this paper we infer the mass composition of the ultra high energy cosmic rays (UHECRs) from measurements of Xmax distributions recorded at the Pierre Auger (2014) and Telescope Array (TA) (2016) ...Observatories, by fitting them with all possible combinations of Monte Carlo (MC) templates from a large set of primary species (p, He, C, N, O, Ne, Si and Fe), as predicted by EPOS-LHC, QGSJETII-04 and Sibyll 2.1 hadronic interaction models. We use the individual fractions of nuclei reconstructed from one experiment in each energy interval to build equivalent MC Xmax distributions, which we compare with the experimental Xmax distributions of the other experiment, applying different statistical tests of compatibility. The results obtained from both experiments confirm that the mass composition of the UHECRs is dominated (≳70%) by protons and He nuclei in the energy range investigated lgE(eV) = 17.8–19.3 (Auger) and lgE(eV) = 18.2–19.0 (TA). The indirect comparisons between the Xmax distributions recorded by the two experiments show that the degree of compatibility of the two datasets is good, even excellent in some high energy intervals, especially above the ankle (lgE(eV)∼18.7). However, our study reveals that, at low energies, further effort in data analysis is required in order to harmonize the results of the two experiments.
The atmospheric depth where the energy deposit profile of secondary particles from extensive air showers (EAS) reaches its maximum,
X
max
, is related to the primary particle mass. The mass ...composition of the ultra-high energy cosmic rays (UHECRs) can be inferred from measurements of
X
max
distributions in each energy interval, by fitting these distributions with Monte Carlo (MC) templates for four primary species (p, He, N and Fe). On the basis of simulations, we show that a high abundance of some intermediate elements in the
X
max
distributions, e.g. Ne or Si, may affect the quality of the fit and also the reconstructed fractions of different species with respect to their true values. We propose a method for finding the “best combination” of elements in each energy interval from a larger set of primaries (p, He, C, N, O, Ne, Si and Fe) which best describes the
X
max
distributions. Applying this method to the
X
max
distributions measured by the Pierre Auger Observatory (2014), we found that the “best combination” of elements which best describe the data suggest the presence of Ne or Si in some low energy bins for the EPOS-LHC model.
The atmospheric depth where the energy deposit profile of secondary particles from extensive air showers (EAS) reaches its maximum, Formula omitted, is related to the primary particle mass. The mass ...composition of the ultra-high energy cosmic rays (UHECRs) can be inferred from measurements of Formula omitted distributions in each energy interval, by fitting these distributions with Monte Carlo (MC) templates for four primary species (p, He, N and Fe). On the basis of simulations, we show that a high abundance of some intermediate elements in the Formula omitted distributions, e.g. Ne or Si, may affect the quality of the fit and also the reconstructed fractions of different species with respect to their true values. We propose a method for finding the "best combination" of elements in each energy interval from a larger set of primaries (p, He, C, N, O, Ne, Si and Fe) which best describes the Formula omitted distributions. Applying this method to the Formula omitted distributions measured by the Pierre Auger Observatory (2014), we found that the "best combination" of elements which best describe the data suggest the presence of Ne or Si in some low energy bins for the EPOS-LHC model.
Abstract The atmospheric depth where the energy deposit profile of secondary particles from extensive air showers (EAS) reaches its maximum, $$X_{\mathrm{max}}$$ Xmax , is related to the primary ...particle mass. The mass composition of the ultra-high energy cosmic rays (UHECRs) can be inferred from measurements of $$X_{\mathrm{max}}$$ Xmax distributions in each energy interval, by fitting these distributions with Monte Carlo (MC) templates for four primary species (p, He, N and Fe). On the basis of simulations, we show that a high abundance of some intermediate elements in the $$X_{\mathrm{max}}$$ Xmax distributions, e.g. Ne or Si, may affect the quality of the fit and also the reconstructed fractions of different species with respect to their true values. We propose a method for finding the “best combination” of elements in each energy interval from a larger set of primaries (p, He, C, N, O, Ne, Si and Fe) which best describes the $$X_{\mathrm{max}}$$ Xmax distributions. Applying this method to the $$X_{\mathrm{max}}$$ Xmax distributions measured by the Pierre Auger Observatory (2014), we found that the “best combination” of elements which best describe the data suggest the presence of Ne or Si in some low energy bins for the EPOS-LHC model.
Abstract
The atmospheric depth where the energy deposit profile of secondary particles from extensive air showers (EAS) reaches its maximum,
$$X_{\mathrm{max}}$$
X
max
, is related to the primary ...particle mass. The mass composition of the ultra-high energy cosmic rays (UHECRs) can be inferred from measurements of
$$X_{\mathrm{max}}$$
X
max
distributions in each energy interval, by fitting these distributions with Monte Carlo (MC) templates for four primary species (p, He, N and Fe). On the basis of simulations, we show that a high abundance of some intermediate elements in the
$$X_{\mathrm{max}}$$
X
max
distributions, e.g. Ne or Si, may affect the quality of the fit and also the reconstructed fractions of different species with respect to their true values. We propose a method for finding the “best combination” of elements in each energy interval from a larger set of primaries (p, He, C, N, O, Ne, Si and Fe) which best describes the
$$X_{\mathrm{max}}$$
X
max
distributions. Applying this method to the
$$X_{\mathrm{max}}$$
X
max
distributions measured by the Pierre Auger Observatory (2014), we found that the “best combination” of elements which best describe the data suggest the presence of Ne or Si in some low energy bins for the EPOS-LHC model.
At ground level, the azimuthal distribution of muons in inclined Extensive Air Showers (EAS) is asymmetric, mainly due to geometric effects. Several EAS observables sensitive to the primary particle ...mass, are constructed after mapping the density of secondary particles from the ground plane to the shower plane (perpendicular to the shower axis). A simple orthogonal projection of the muon coordinates onto this plane distorts the azimuthal symmetry in the shower plane. Using CORSIKA simulations, we correct for this distortion by projecting each muon onto the normal plane following its incoming direction, taking also into account the attenuation probability. We show that besides restoring the azimuthal symmetry of muons density around the shower axis, the application of this procedure has a significant impact on the reconstruction of the distribution of the muon production depth and of its maximum, Xmaxμ, which is an EAS observable sensitive to the primary particle mass. Our results qualitatively suggest that not including it in the reconstruction process of Xmaxμ may introduce a bias in the results obtained by analyzing the actual data on the basis of Monte Carlo simulations.
Quantum production of black holes at colliders Arsene, Nicusor; Casadio, Roberto; Micu, Octavian
European physical journal. C, Particles and fields,
07/2016, Volume:
76, Issue:
7
Journal Article
Peer reviewed
Open access
We investigate black hole production in
p
p
collisions at the Large Hadron Collider by employing the horizon quantum mechanics for models of gravity with extra spatial dimensions. This approach can ...be applied to processes around the fundamental gravitational scale and naturally yields a suppression below the fundamental gravitational scale and for increasing number of extra dimensions. The results of numerical simulations performed with the black hole event generator BLACKMAX are here reported in order to illustrate the main differences in the numbers of expected black hole events and mass distributions.
The presence of hadronic sub-showers causes azimuthal non-uniformity in the particle distributions on the ground in vertical air showers. The \(LCm\) parameter, which quantifies the non-uniformity of ...the signal recorded in detectors located at a given distance on a ring around the shower axis, has been successfully introduced as a gamma/hadron discriminator at PeV energies \cite{Conceicao:2022lkc}. In this work, we demonstrate that the \(LCm\) parameter can effectively serve as a mass composition discriminator in experiments that employ a compact array of detectors, like KASCADE. We reconstruct the \(LCm\) parameter distributions in the energy range \(\lg(E/\rm eV) = 15.0 \text{ - } 16.0\) using measurements from the KASCADE experiment, with intervals of \(\lg(E/\rm eV) = 0.2\), which are then fitted with MC templates for five primary nuclei species p, He, C, Si, and Fe considering three hadronic interaction models: QGSjet-II-04, EPOS-LHC and SIBYLL 2.3d. We find that the \(LCm\) parameter exhibits minimal dependence on the specific hadronic interaction model considered. The reconstructed fractions of individual species demonstrate a linear decrease in the abundance of protons and He nuclei with increasing energy, while the heavier components become prevalent above the \textit{knee} as predicted by all three hadronic interaction models. Our findings indicate that the abundance of particle types as a function of energy aligns with different astrophysical models that link the \textit{knee} to the acceleration and propagation of cosmic rays within the Galaxy. Furthermore, they also demonstrate excellent agreement with three more recent data-driven astrophysical models. These findings suggest that the \(LCm\) parameter could be a valuable tool for forthcoming measurements of the LHAASO experiment to enhance our knowledge about the origin and acceleration mechanisms of cosmic rays.
In this paper we study, using Monte Carlo simulations, the possibility to discriminate the mass of the Ultra High Energy Cosmic Rays (UHECRs) by combining information obtained from the maximum Xmaxμ ...of the muon production rate longitudinal profile of Extensive Air Showers (EAS) and the number of muons, Nμ, which hit an array of detectors located in the horizontal plane. We investigate the sensitivity of the 2D distribution Xmaxμ versus Nμ to the mass of the primary particle generating the air shower. To this purpose we analyze a set of CORSIKA showers induced by protons and iron nuclei at energies of 1019 eV and 1020 eV, at five angles of incidence, 0°, 37°, 48°, 55° and 60°. Using the simulations we obtain the 2D Probability Functions Prob(Xmaxμ,Nμ|p) and Prob(Xmaxμ,Nμ|Fe) which give the probability that a shower induced by a proton or iron nucleus contributes to a specific point on the plane (Xmaxμ,Nμ). Then we construct the probability functions Prob(p|Xmaxμ,Nμ) and Prob(Fe|Xmaxμ,Nμ) which give the probability that a certain point on the plane (Xmaxμ,Nμ) corresponds to a shower initiated by a proton or an iron nucleus, respectively. Finally, a test of this procedure using a Bayesian approach, confirms an improved accuracy of the primary mass estimation in comparison with the results obtained using only the Xmaxμ distributions.
We propose a decay signature for non-thermal small black holes with masses in the TeV range which can be discovered by neutrino observatories. The black holes would result due to the impact between ...ultra high energy neutrinos with nuclei in water or ice and decay instantaneously. They could be produced if the Planck scale is in the few TeV region and the highly energetic fluxes are large enough. Having masses close to the Planck scale, the typical decay mode for these black holes is into two particles emitted back-to-back. For a certain range of angles between the emitted particles and the center of mass direction of motion, it is possible for the detectors to measure separate muons having specific energies and their trajectories oriented at a large enough angle to prove that they are the result of a back-to-back decay event.
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