Publications (81)
Sibyll: ad-hoc modifications for an improved description of muon data in extensive air showers
Felix Riehn, Ralph Engel, Anatoli Fedynitch
Current simulations of air showers produced by ultra-high energy cosmic rays (UHECRs) do not satisfactorily describe recent experimental data, particularly when looking at the muon…
Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy
The Pierre Auger Collaboration, Alexander Aab, Pedro Abreu +447
We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Au…
Measurement of the cosmic ray spectrum above eV using inclined events detected with the Pierre Auger Observatory
The Pierre Auger Collaboration, Alexander Aab, Pedro Abreu +461
A measurement of the cosmic-ray spectrum for energies exceeding eV is presented, which is based on the analysis of showers with zenith angles greater than $60^{\…
Test of hadronic interaction models with data from the Pierre Auger Observatory
Ralph Engel
The Pierre Auger Observatory allows the measurement of both longitudinal profiles and lateral particle distributions of high-energy showers. The former trace the overall shower dev…
Towards a Next Generation of CORSIKA: A Framework for the Simulation of Particle Cascades in Astroparticle Physics
Ralph Engel, Dieter Heck, Tim Huege +6
A large scientific community depends on the precise modelling of complex processes in particle cascades in various types of matter. These models are used most prevalently in cosmic…
The Giant Radio Array for Neutrino Detection (GRAND): Science and Design
GRAND Collaboration, Jaime Alvarez-Muniz, Rafael Alves Batista +48
The Giant Radio Array for Neutrino Detection (GRAND) is a planned large-scale observatory of ultra-high-energy (UHE) cosmic particles, with energies exceeding 10^8 GeV. Its goal is…
Influence of shower fluctuations and primary composition on studies of the shower longitudinal development
Jaime Alvarez-Muñiz, Ralph Engel, T. K. Gaisser +2
We study the influence of shower fluctuations, and the possible presence of different nuclear species in the primary cosmic ray spectrum, on the experimental determination of both…
Proton-Air Cross Section and Extensive Air Showers
Ralf Ulrich, Ralph Engel, Steffen Müller +2
Hadronic cross sections at ultra-high energy have a significant impact on the development of extensive air shower cascades. Therefore the interpretation of air shower data depends…
Antiprotons at Solar Maximum
John W. Bieber, R. A. Burger, Ralph Engel +3
New measurements with good statistics will make it possible to observe the time variation of cosmic antiprotons at 1 AU through the approaching peak of solar activity. We report a…
Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory
The Pierre Auger Collaboration, Alexander Aab, Pedro Abreu +448
The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared…
Sources of Cosmic Rays and Galactic Diffuse Gamma Radiation
Sabrina Casanova, Peter L. Biermann, Ralph Engel +2
The diffuse galactic gamma-ray spectrum measured by the EGRET experiment \citep{Hunter:1997} are interpreted within a scenario in which cosmic rays (CRs) are injected by three diff…
Signal Model and Energy Reconstruction for the Radio Detection of Inclined Air Showers in the 50-200 MHz Frequency Band
Lukas Gülzow, Ralph Engel, Tim Huege +2
The radio emission of cosmic-ray air-showers changes significantly depending on parameters like signal frequency, magnetic field configuration and observing altitude. We use CoREAS…
Data-driven model of the cosmic-ray flux and mass composition from 10 GeV to GeV
Hans Dembinski, Ralph Engel, Anatoli Fedynitch +3
We present a new parametrization of the cosmic-ray flux and its mass composition over an energy range from 10 GeV to GeV. Our approach is data-driven and relies on theore…
Mass Composition Sensitivity of an Array of Water Cherenkov and Scintillation Detectors
Javier G. Gonzalez, Ralph Engel, Markus Roth
We consider a hybrid array composed of scintillation and water Cherenkov detectors designed to measure the cosmic ray primary mass composition at energies of about 1 EeV. We have d…
Implications of HERA results for very high energy cosmic ray physics
Ralph Engel
Experimental results obtained with the HERA collider and recent progress in their theoretical interpretation are reviewed. After a short introduction to HERA physics, deep inelasti…
Search for dark matter in the hidden-photon sector with a large spherical mirror
The FUNK Experiment, :, Darko VeberiÄ +11
If dark matter consists of hidden-sector photons which kinetically mix with regular photons, a tiny oscillating electric-field component is present wherever we have dark matter. In…
Neural Network for Simulating Radio Emission from Extensive Air Showers
Pranav Sampathkumar, Tim Huege, Andreas Haungs +1
Cosmic ray shower detection using large radio arrays has gained significant traction in recent years. With massive improvements in signal modelling and microscopic simulations, the…
Hidden Photon Dark Matter Search with a Large Metallic Mirror
Babette Döbrich, Kai Daumiller, Ralph Engel +4
If Dark Matter is composed of hidden-sector photons that kinetically mix with photons of the visible sector, then Dark Matter has a tiny oscillating electric field component. Its p…
Proof of principle for template synthesis approach for the radio emission from vertical extensive air showers
Mitja Desmet, Stijn Buitink, Tim Huege +3
The radio detection technique of cosmic ray air showers has gained renewed interest in the last two decades. While the radio experiments are very cost-effective to deploy, the Mont…
A new version of the event generator Sibyll
Felix Riehn, Ralph Engel, Anatoli Fedynitch +2
The event generator Sibyll can be used for the simulation of hadronic multiparticle production up to the highest cosmic ray energies. It is optimized for providing an economic desc…
Charm production in SIBYLL
Ralph Engel, Anatoli Fedynitch, Thomas K. Gaisser +2
SIBYLL 2.1 is an event generator for hadron interactions at the highest energies. It is commonly used to analyze and interpret extensive air shower measurements. In light of the fi…
Towards the Giant Radio Array for Neutrino Detection (GRAND): the GRANDProto300 and GRAND@Auger prototypes
GRAND Collaboration, Jaime Ãlvarez-Muniz, Rafael Alves Batista +118
The Giant Radio Array for Neutrino Detection (GRAND) is a proposed multi-messenger observatory of Ultra-High-Energy (UHE) particles of cosmic origin. Its main goal is to find the l…
Ideas and Requirements for the Global Cosmic-Ray Observatory (GCOS)
Markus Ahlers, Ingo Allekotte, Jaime Alvarez-Muniz +136
After a successful kick-off meeting in 2021. two workshops in 2022 and 2023 on the future Global Cosmic-Ray Observatory (GCOS) focused mainly on a straw man design of the detector…
Sterile-neutrino search based on 259 days of KATRIN data
Himal Acharya, Max Aker, Dominic Batzler +132
Neutrinos are the most abundant fundamental matter particles in the Universe and play a crucial role in particle physics and cosmology. Neutrino oscillation, discovered about 25 ye…
Very High Energy Cosmic Rays and Their Interactions
Ralph Engel
The investigation of high energy cosmic rays and their interactions is a very active field of research. This article summarizes the progress made during the last years as reflected…
The FUNK search for Hidden Photon Dark Matter in the eV range
Babette Döbrich, Kai Daumiller, Ralph Engel +9
We give a brief update on the search for Hidden Photon Dark Matter with FUNK. The experiment uses a large spherical mirror, which, if Hidden Photon Dark Matter exists in the access…
Asymmetry of the angular distribution of Cherenkov photons of extensive air showers induced by the geomagnetic field
Piotr Homola, Ralph Engel, Henryk WilczyÅski
The angular distribution of Cherenkov light in an air shower is closely linked to that of the shower electrons and positrons. As charged particles in extensive air showers are defl…
Hadronic Multiparticle Production at Ultra-High Energies and Extensive Air Showers
Ralf Ulrich, Ralph Engel, Michael Unger
Studies of the nature of cosmic ray particles at the highest energies are based on the measurement of extensive air showers. Most cosmic ray properties can therefore only be obtain…
Propagation of ultra-high energy protons in the nearby universe
Todor Stanev, Ralph Engel, Anita Muecke +2
We present a new calculation of the propagation of protons with energies above eV over distances of up to several hundred Mpc. The calculation is based on a Monte Carlo a…
Event Generators
Leif Lonnblad, Mike Seymour, Edouard Boudinov +14
The report from the working group on 'γγEvent Generators' of the LEP 2 workshop
The Giant Radio Array for Neutrino Detection (GRAND) Collaboration -- Contributions to the 39th International Cosmic Ray Conference (ICRC 2025)
Jaime Ãlvarez-Muñiz, Rafael Alves Batista, Aurélien Benoit-Lévy +133
The Giant Radio Array for Neutrino Detection (GRAND) is an envisioned observatory of ultra-high-energy particles of cosmic origin, with energies in excess of 100 PeV. GRAND uses la…
Hybrid simulations of extensive air showers
Jaime Alvarez-Muñiz, Ralph Engel, T. K. Gaisser +2
We present a fast one dimensional hybrid method to efficiently simulate extensive air showers up to the highest observed energies. Based on precalculated pion showers and a bootstr…
A Model of the Response of Surface Detectors to Extensive Air Showers Based on Shower Universality
Maximilian Stadelmaier, Ralph Engel, Markus Roth +2
We present a full model of surface-detector responses to extensive air showers. The model is motivated by the principles of air-shower universality and can be applied to different…
Cosmic-ray Monte Carlo predictions for forward particle production in p-p, p-Pb, and Pb-Pb collisions at the LHC
David d'Enterria, Ralph Engel, Thomas McCauley +1
We present and compare the predictions of various cosmic-ray Monte Carlo models for the energy (dE/deta) and particle (dN/deta) flows in p-p, p-Pb and Pb-Pb collisions at sqrt(s) =…
Calculation of rescaling factors and nuclear multiplication of muons in extensive air showers
Kevin Almeida Cheminant, Dariusz Góra, Nataliia Borodai +7
Recent results obtained from leading cosmic ray experiments indicate that simulations using LHC-tuned hadronic interaction models underestimate the number of muons in extensive air…
Template synthesis approach for radio emission from extensive air showers
Mitja Desmet, Stijn Buitink, David Butler +3
We present a novel way to synthesise the radio emission from extensive air showers. It is a hybrid approach which uses a single microscopic Monte-Carlo simulation to generate the r…
CORSIKA 8 -- Contributions to the 37th International Cosmic Ray Conference in Berlin Germany (ICRC 2021)
Jean-Marco Alameddine, Johannes Albrecht, Jaime Alvarez-Muniz +39
Compilation of the six contributions to the ICRC conference 2021 by the CORSIKA 8 Collaboration. The status of the project is illustrated. In particular, the secondary hadron as we…
An improved limit to the diffuse flux of ultra-high energy neutrinos from the Pierre Auger Observatory
The Pierre Auger Collaboration, Alexander Aab, Pedro Abreu +462
Neutrinos in the cosmic ray flux with energies near 1 EeV and above are detectable with the Surface Detector array of the Pierre Auger Observatory. We report here on searches throu…
Calculation of conventional and prompt lepton fluxes at very high energy
Anatoli Fedynitch, Ralph Engel, Thomas K. Gaisser +2
An efficient method for calculating inclusive conventional and prompt atmospheric leptons fluxes is presented. The coupled cascade equations are solved numerically by formulating t…
Low-Energy Hadron Production Data and Current Status of CERN Measurements
Giles Barr, Ralph Engel
Data on low-energy hadron production in collisions of nucleons, pions and kaons with light nuclei are needed for many astrophysical and accelerator applications. Modern simulations…
Pion production in proton collisions with light nuclei: implications for atmospheric neutrinos
Ralph Engel, T. K. Gaisser, Todor Stanev
Differences among calculations of the atmospheric neutrino beam can be traced in large part to differences in the representation of pion production by protons interacting with nucl…
UHECR propagation in the Galaxy: clustering versus isotropy
Jaime Alvarez-Muñiz, Ralph Engel, Todor Stanev
Recently the AGASA Collaboration presented data suggesting a significant clustering of ultra-high energy cosmic rays coming from the outer Galaxy region. In this paper we calculate…
The Monte Carlo Event Generator DPMJET-III
Stefan Roesler, Ralph Engel, Johannes Ranft
A new version of the Monte Carlo event generator DPMJET is presented. It is a code system based on the Dual Parton Model and unifies all features of the DTUNUC-2, DPMJET-II and PHO…
Method for calculation of the beta exponent from the Heitler-Matthews model of hadronic air showers
Kevin Almeida Cheminant, Dariusz Gora, Nataliia Borodai +8
The number of muons in an air shower is a strong indicator of the mass of the primary particle and increases with a small power of the cosmic ray mass by the -exponent, $N_μ \…
Neutrinos from propagation of ultra-high energy protons
Ralph Engel, David Seckel, Todor Stanev
We present a calculation of the production of neutrinos during propagation of ultra-high energy cosmic rays from their astrophysical sources to us. Photoproduction interactions are…
Proton-proton Cross Section at sqrt(s) \sim 30 TeV
Ralph Engel, T. K. Gaisser, Paolo Lipari +1
There are both theoretical and experimental uncertainties in using data from cosmic-ray air showers to estimate hadronic cross sections above accelerator energies. We outline these…
Sibyll with charm
Eun-Joo Ahn, Ralph Engel, Thomas K. Gaisser +2
The cosmic ray interaction event generator Sibyll is widely used in extensive air shower simulations for cosmic ray and neutrino experiments. Charmed particle production has been a…
GRANDlib: A simulation pipeline for the Giant Radio Array for Neutrino Detection (GRAND)
GRAND Collaboration, Rafael Alves Batista, Aurélien Benoit-Lévy +112
The operation of upcoming ultra-high-energy cosmic-ray, gamma-ray, and neutrino radio-detection experiments, like the Giant Radio Array for Neutrino Detection (GRAND), poses signif…
Generative Neural Network for Simulating Radio Emission from Extensive Air Showers
Pranav Sampathkumar, Tim Huege, Andreas Haungs +1
Cosmic ray shower detection using large radio arrays has gained significant traction in recent years. With massive improvements in signal modelling and microscopic simulations, the…
The hadronic interaction model SIBYLL 2.3c and Feynman scaling
Felix Riehn, Hans P. Dembinski, Ralph Engel +3
The Monte Carlo model Sibyll has been designed for efficient simulation of hadronic multiparticle production up to the highest energies as needed for interpreting cosmic ray measur…
The strong interaction at the collider and cosmic-rays frontiers
David d'Enterria, Ralph Engel, Tanguy Pierog +2
First data on inclusive particle production measured in proton-proton collisions at the Large Hadron Collider (LHC) are compared to predictions of various hadron-interaction Monte…
Monte-Carlo simulations of photohadronic processes in astrophysics
A. Muecke, Ralph Engel, J. P. Rachen +2
A new Monte Carlo program for photohadronic interactions of relativistic nucleons with an ambient photon radiation field is presented. The event generator is designed to fulfil typ…
The Pierre Auger Observatory: Contributions to the 33rd International Cosmic Ray Conference (ICRC 2013)
The Pierre Auger Collaboration, Alexander Aab, Pedro Abreu +495
Contributions of the Pierre Auger Collaboration to the 33rd International Cosmic Ray Conference, Rio de Janeiro, Brazil, July 2013
Universality and template synthesis of cosmic ray air shower radio emission
David Butler, Tim Huege, Ralph Engel +1
Accurate prediction of the radio emission from cosmic ray air showers relies on computationally demanding Monte Carlo simulations such as CoREAS. We aim to expedite this process vi…
Propagation of ultra-high energy protons in regular extragalactic magnetic fields
Todor Stanev, David Seckel, Ralph Engel
We study the proton flux expected from sources of ultra high energy cosmic rays (UHECR) in the presence of regular extragalactic magnetic fields. It is assumed that a local source…
Disentangling the Air Shower Components Using Scintillation and Water Cherenkov Detectors
Javier G. Gonzalez, Markus Roth, Ralph Engel
We consider a ground array of scintillation and water Cherenkov detectors with the purpose of determining the muon content of air showers. The different response characteristics of…
Atmospheric shower fluctuations and the constant intensity cut method
Jaime Alvarez-Muniz, Ralph Engel, T. K. Gaisser +2
We explore the constant intensity cut method that is widely used for the derivation of the cosmic ray energy spectrum, for comparisons of data obtained at different atmospheric dep…
Road map for the tuning of hadronic interaction models with accelerator-based and astroparticle data
Johannes Albrecht, Julia Becker Tjus, Noah Behling +52
In high-energy and astroparticle physics, event generators play an essential role, even in the simplest data analyses. As analysis techniques become more sophisticated, e.g. based…
Sibyll
Felix Riehn, Anatoli Fedynitch, Ralph Engel
In the last decade, an increasing number of datasets have revealed a consistent discrepancy between the number of muons measured in ultra-high-energy extensive air showers (EAS) an…
Open Questions in Cosmic-Ray Research at Ultrahigh Energies
Rafael Alves Batista, Jonathan Biteau, Mauricio Bustamante +13
We review open questions and prospects for progress in ultrahigh-energy cosmic ray (UHECR) research, based on a series of discussions that took place during the `The High-Energy Un…
The ultra-high energy cosmic rays image of Virgo A
RadomÃr Å mÃda, Ralph Engel
Arrival directions of ultra-high energy cosmic rays from the direction of ten brightest radio sources lying within 50 Mpc from our Galaxy were studied by using recent models of the…
On the measurement of the proton-air cross section using air shower data
Ralf Ulrich, Johannes Blümer, Ralph Engel +2
The analysis of high-energy air shower data allows one to study the proton-air cross section at energies beyond the reach of fixed target and collider experiments. The mean depth o…
The last Gamma Ray Burst in our Galaxy? On the observed cosmic ray excess at particle energy 1 EeV
Peter L. Biermann, Gustavo Medina-Tanco, Ralph Engel +1
Here we propose that the excess flux of particle events of energy near 1 EeV from the direction of the Galactic Center region is due to the production of cosmic rays by the last fe…
The hadronic interaction model Sibyll-2.3c and inclusive lepton fluxes
Anatoli Fedynitch, Felix Riehn, Ralph Engel +2
Muons and neutrinos from cosmic ray interactions in the atmosphere originate from decays of mesons in air-showers. Sibyll-2.3c aims to give a precise description of hadronic intera…
The Einstein Telescope Pathfinder and its Vacuum System
Thomas Höhn, Adrian Schwenck, Thomas Thümmler +5
The Einstein Telescope (ET) will be the next generation gravitational wave observatory in Europe with a sensitivity reaching beyond the CMB into the dark era of the Universe. Each…
Extensive Air Showers and Accelerator Data - The NEEDS Workshop
Ralph Engel
Very high energy cosmic rays are typically studied by measuring extensive air showers formed by secondary particles produced in collisions with air nuclei. The indirect character o…
Soft interactions (presented at ISMD31)
Ralph Engel
A brief introduction to the theory and phenomenology of soft interactions is given, focusing on total and elastic cross sections and multiparticle production.
On the measurement of the proton-air cross section using cosmic ray data
Ralf Ulrich, Johannes Bluemer, Ralph Engel +2
Cosmic ray data may allow the determination of the proton-air cross section at ultra-high energy. For example, the distribution of the first interaction point in air showers reflec…
The Giant Radio Array for Neutrino Detection (GRAND) Collaboration -- Contributions to the 38th International Cosmic Ray Conference (ICRC 2023)
GRAND Collaboration, Rafael Alves Batista, Aurélien Benoit-Lévy +96
The Giant Radio Array for Neutrino Detection (GRAND) is an envisioned observatory of ultra-high-energy particles of cosmic origin, with energies in excess of 100 PeV. GRAND uses la…
Neutron Production in Simulations of Extensive Air Showers
Martin Schimassek, Ralph Engel, Alfredo Ferrari +3
Although the electromagnetic and muonic components of extensive air showers have been studied in great detail, no comprehensive simulation study of the neutron component is availab…
The muon deficit problem: a new method to calculate the muon rescaling factors and the Heitler-Matthews beta exponent
Kevin Almeida Cheminant, Dariusz Góra, Nataliia Borodai +8
Simulations of extensive air showers using current hadronic interaction models predict too small numbers of muons compared to events observed in the air-shower experiments, which i…
Muon number rescaling in simulations of air showers
Dariusz Góra, Nataliia Borodai, Ralph Engel +7
The number of muons in extensive air showers predicted using LHC-tuned hadronic interaction models, such as EPOS-LHC and QGSJetII-04, is smaller than observed in showers recorded b…
Anomalous Longitudinal Shower Profiles and Hadronic Interactions
Colin Baus, Ralph Engel, Tanguy Pierog +2
The bulk of air showers initiated by very high energy cosmic rays exhibits a longitudinal development in depth with a single well-defined shower maximum. However, a small fraction…
Constraints from the first LHC data on hadronic event generators for ultra-high energy cosmic-ray physics
David d'Enterria, Ralph Engel, Tanguy Pierog +2
The determination of the primary energy and mass of ultra-high-energy cosmic-rays (UHECR) generating extensive air-showers in the Earth's atmosphere, relies on the detailed modelin…
Cosmic ray event generator Sibyll 2.1
Eun-Joo Ahn, Ralph Engel, Thomas K. Gaisser +2
The cosmic ray interaction event generator Sibyll is widely used in extensive air shower simulations. We describe in detail the properties of Sibyll 2.1 and the differences with th…
Hunting super-heavy dark matter with ultra-high energy photons
Luis A. Anchordoqui, Corinne Berat, Mario E. Bertaina +17
At any epoch, particle physics must be open to completely unexpected discoveries, and that is reason enough to extend the reach of searches for ultra-high energy (UHE) photons. The…
On the measurement of the proton-air cross section using longitudinal shower profiles
Ralf Ulrich, Johannes Blümer, Ralph Engel +2
In this paper, we will discuss the prospects of deducing the proton-air cross section from fluorescence telescope measurements of extensive air showers. As it is not possible to ob…
The Giant Radio Array for Neutrino Detection (GRAND) Collaboration -- Contributions to the 10th International Workshop on Acoustic and Radio EeV Neutrino Detection Activities (ARENA 2024)
Rafael Alves Batista, Aurélien Benoit-Lévy, Teresa Bister +121
This is an index of the contributions by the Giant Radio Array for Neutrino Detection (GRAND) Collaboration to the 10th International Workshop on Acoustic and Radio EeV Neutrino De…
Hadronic interaction model Sibyll 2.3d and extensive air showers
Felix Riehn, Ralph Engel, Anatoli Fedynitch +2
We present a new version of the hadron interaction event generator Sibyll. While the core ideas of the model have been preserved, the new version handles the production of baryon p…
Simulation of ultra-high energy photon propagation with PRESHOWER 2.0
Piotr Homola, Ralph Engel, Agata Pysz +1
In this paper we describe a new release of the PRESHOWER program, a tool for Monte Carlo simulation of propagation of ultra-high energy photons in the magnetic field of the Earth.…
Sensitivity of Extensive Air Showers to Features of Hadronic Interactions at Ultra-High Energies
Ralf Ulrich, Ralph Engel, Steffen Müller +3
We study the dependence of extensive air shower development on the first hadronic interactions at ultra-high energies occurring in the startup phase of the air shower cascade. The…