TeV Black Hole Fragmentation and Detectability in Extensive Air Showers

In models with large extra dimensions, particle collisions with a center-of-mass energy larger than the fundamental gravitational scale can generate nonperturbative gravitational objects. Since cosmic rays have been observed with energies above 108 TeV, gravitational effects in the TeV energy range can, in principle, be observed by ultrahigh energy cosmic ray detectors. We consider the interaction of ultrahigh energy neutrinos in the atmosphere and compare extensive air showers from TeV black hole formation and fragmentation with standard model processes. Departures from the standard model predictions arise in the interaction cross sections and in the multiplicity of secondary particles. Large theoretical uncertainties in the black hole cross section weaken attempts to constrain TeV gravity based solely on differences between predicted and observed event rates. The large multiplicity of secondaries in black hole fragmentation enhances the detectability of TeV gravity effects. We simulate TeV black hole air showers using PYTHIA and AIRES, and find that black-hole-induced air showers are quite distinct from standard model air showers. However, the limited amount of information registered by realistic detectors together with large air shower fluctuations limit in practice the ability to distinguish TeV gravity events from standard model events in a shower by shower case. We discuss possible strategies to optimize the detectability of black hole events and propose a few unique signatures that may allow future high statistics detectors to separate black hole from standard model events

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

A new technique to measure cosmic ray energy and composition via (2+1)d lateral distribution function fits to surface detector array data

The concept of a one-dimensional lateral distribution function is extended to a set of (2+1)d functions which describe the spatial and temporal distributions of the muonic and electromagnetic components of extended air showers. By design, these functions incorporate the curvature and time structure of the shower front as well as the asymmetries in particle density and in time structure expected in inclined showers. These observables are sensitive to the mass of the primary cosmic ray and to the details of the hadronic interactions inducing the air shower. The (2+1)d functions smoothly interpolate between the values of X{sub max} and muon flux predicted by various simulations performed with different assumptions of primary composition and interaction model. A maximum likelihood fit to surface detector array data can then give simultaneous event-by-event measurements of the shower energy, X{sub max}, and the muon content, from which the primary composition may subsequently be inferred. The methods outlined are applicable to a large number of existing and future shower detector arrays covering a range of energies

Detecting Tev Black Holes from Extensive Air Showers

In models with large extra dimensions particle collisions with centre-of-mass energy larger than the fundamental gravitational scale can generate non-perturbative gravitational objects such as black holes and branes. They might be created in the next generation particle colliders or by neutrino induced air showers in the Earth\u27s atmosphere. The decay of these non-perturbative gravitational objects is significantly different from other standard model processes. We present a comprehensive study of how to differentiate extensive air showers generated by TeV gravity effects from those generated by standard model interactions

An universal description of the particle flux distributions in extended air showers

It is shown that the electromagnetic and muonic fluxes in extended air showers (EAS) can be described using a simple model incorporating attenuation and geometrical dispersion. The model uses a reduced set of parameters including the primary energy E, the position of shower maximum X{sub max} relative to the ground, and a muon flux normalization N{sub {mu}}. To a good approximation, this set of three physical parameters is sufficient to predict the variability of the particle fluxes due to systematic differences between different models of composition and hadronic interactions, and due to statistical event-by-event differences in shower development. Measurements of these three physical observables are therefore unbiased and very nearly model-independent, in contrast with standard measurement techniques. The theoretical problem of determining primary composition is thus deconvolved from the measurement procedure, and may be approached in a subsequent analysis of the measured distributions of (E, X{sub max}, N{sub {mu}})

Science and mission status of EUSO-SPB2

The Extreme Universe Space Observatory on a Super Pressure Balloon II (EUSO-SPB2) is a second generation stratospheric balloon instrument for the detection of Ultra High Energy Cosmic Rays (UHECRs, E > 1 EeV) via the fluorescence technique and of Very High Energy (VHE, E > 10 PeV) neutrinos via Cherenkov emission. EUSO-SPB2 is a pathfinder mission for instruments like the proposed Probe Of Extreme Multi-Messenger Astrophysics (POEMMA). The purpose of such a space-based observatory is to measure UHECRs and UHE neutrinos with high statistics and uniform exposure. EUSO-SPB2 is designed with two Schmidt telescopes, each optimized for their respective observational goals. The Fluorescence Telescope looks at the nadir to measure the fluorescence emission from UHECR-induced extensive air shower (EAS), while the Cherenkov Telescope is optimized for fast signals (∼10 ns) and points near the Earth's limb. This allows for the measurement of Cherenkov light from EAS caused by Earth skimming VHE neutrinos if pointed slightly below the limb or from UHECRs if observing slightly above. The expected launch date of EUSO-SPB2 is Spring 2023 from Wanaka, NZ with target duration of up to 100 days. Such a flight would provide thousands of VHECR Cherenkov signals in addition to tens of UHECR fluorescence tracks. Neither of these kinds of events have been observed from either orbital or suborbital altitudes before, making EUSO-SPB2 crucial to move forward towards a space-based instrument. It will also enhance the understanding of potential background signals for both detection techniques. This contribution will provide a short overview of the detector and the current status of the mission as well as its scientific goals.ISSN:1824-803