AugerPrime: the Pierre Auger Observatory Upgrade

The world largest exposure to ultra-high energy cosmic rays accumulated by the Pierre Auger Observatory led to major advances in our understanding of their properties, but the many unknowns about the nature and distribution of the sources, the primary composition and the underlying hadronic interactions prevent the emergence of a uniquely consistent picture. The new perspectives opened by the current results call for an upgrade of the Observatory, whose main aim is the collection of new information about the primary mass of the highest energy cosmic rays on a shower-by-shower basis. The evaluation of the fraction of light primaries in the region of suppression of the flux will open the window to charged particle astronomy, allowing for composition-selected anisotropy searches. In addition, the properties of multiparticle production will be studied at energies not covered by man-made accelerators and new or unexpected changes of hadronic interactions will be searched for. After a discussion of the motivations for upgrading the Pierre Auger Observatory, a description of the detector upgrade is provided. We then discuss the expected performances and the improved physics sensitivity of the upgraded detectors and present the first data collected with the already running Engineering Array.Comment: 9 pages, 11 figures, presented at UHECR 2018 (Paris, Oct 2018

Astroparticle and particle physics at ultra-high energy: results from the Pierre Auger Observatory

The scientific achievements of the Pierre Auger Collaboration cover diverse and complementary fields of research. The search for the origin of ultra-high energy cosmic rays (UHECRs) is based on the measurement of the energy spectrum and mass composition of the primaries, on studies of multi-messengers, and on extensive anisotropy searches. With the collected data it is also possible to explore the characteristics of hadronic interactions at energies unreachable at human-made accelerators, and to assess the existence of non-standard physics effects. A selection of the latest results is presented and the emerging picture is discussed.Comment: Submission to SciPost Phys. Pro

Auger Highlights

The Pierre Auger Observatory has been designed to investigate the origin and nature of the ultra high energy cosmic rays using a hybrid detection technique. A review of selected results is presented, with the emphasis given to the measurement of energy spectrum, mass composition and arrival directions

Auger Highlights

The Pierre Auger Observatory has been designed to investigate the origin and nature of the ultra high energy cosmic rays using a hybrid detection technique. A review of selected results is presented, with the emphasis given to the measurement of energy spectrum, mass composition and arrival directions

Astroparticelle di altissima energia

La fisica astro-particellare è un campo interdisciplinare giovane, che studia la radiazione e le particelle del cosmo utilizzando tecniche tipiche degli esperimenti di alta energia. Alcune di queste particelle cosmiche raggiungono energie incredibilmente elevate, ed il loro studio è uno degli argomenti più affascinanti dell'astrofisica moderna. Questi messaggeri ultra-energetici dallo spazio profondo possono raggiungere la Terra ed essere osservati con apparati sperimentali dedicati e ci forniscono informazioni ineguagliabili sulle loro sorgenti e sulla struttura dell'Universo

Astroparticelle di altissima energia

La fisica astro-particellare è un campo interdisciplinare giovane, che studia la radiazione e le particelle del cosmo utilizzando tecniche tipiche degli esperimenti di alta energia. Alcune di queste particelle cosmiche raggiungono energie incredibilmente elevate, ed il loro studio è uno degli argomenti più affascinanti dell'astrofisica moderna. Questi messaggeri ultra-energetici dallo spazio profondo possono raggiungere la Terra ed essere osservati con apparati sperimentali dedicati e ci forniscono informazioni ineguagliabili sulle loro sorgenti e sulla struttura dell'Universo

Diffusion coefficient and acceleration spectrum from direct measurements of charged cosmic ray nuclei

We discuss the potentials of several experimental configurations dedicated to direct measurements of charged cosmic ray (CR) nuclei at energies \gsim 100 GeV/n. Within a two-zone propagation model for stable CRs, we calculate light primary and secondary nuclei fluxes for different diffusion and acceleration schemes. We show that the new detectors exploiting the long and ultra long duration balloon flights could determine the diffusion coefficient power index $\delta$ through the measurement of the boron-to-carbon ratio with an uncertainty of about 10-15 %, if systematic errors are low enough. Only space-based or satellite detectors will be able to determine $\delta$ with very high accuracy even in the case of important systematic errors, thanks to the higher energy reach and the less severe limitations in the exposure. We show that no uncertainties other than those on $\delta$ affect the determination of the acceleration slope $\alpha$, so that measures of light primary nuclei, such as the carbon one, performed with the same experiments, will provide valuable information on the acceleration mechanisms.Comment: 20 pages, 6 figs., Astropart. Physics, in pres

Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

A measurement of the cosmic-ray spectrum for energies exceeding $4{\times}10^{18}$ eV is presented, which is based on the analysis of showers with zenith angles greater than $60^{\circ}$ detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above $5.3{\times}10^{18}$ eV, the "ankle", the flux can be described by a power law $E^{-\gamma}$ with index $\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)}$ followed by a smooth suppression region. For the energy ($E_\text{s}$) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find $E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19}$ eV.Comment: Replaced with published version. Added journal reference and DO