634 research outputs found
Measurements and tests of hadronic interactions at ultra-high energies with the Pierre Auger Observatory
Extensive air showers are complex objects, resulting of billions of particle
reactions initiated by single cosmic ray at ultra-high-energy. Their
characteristics are sensitive both to the mass of the primary cosmic ray and to
the details of hadronic interactions. Many of the interactions that determine
the shower features occur in kinematic regions and at energies beyond those
tested by human-made accelerators. We will report on the measurement of the
proton-air cross section for particle production at a center-of-mass energy per
nucleon of 39 TeV and 56 TeV. We will also show comparisons of post-LHC
hadronic interaction models with shower data by studying the moments of the
distribution of the depth of the electromagnetic maximum, the number and
production depth of muons in air showers, and finally a parameter based on the
rise-time of the surface detector signal, sensitive to the electromagnetic and
muonic component of the shower. While there is good agreement found for
observables based on the electromagnetic shower component, discrepancies are
observed for muon-sensitive quantities.Comment: Ultra High Energy Cosmic Rays 2018 (UHECR2018
The interplay between the electromagnetic and the muonic longitudinal profile at production
The electromagnetic and the muonic longitudinal profile at production
enclosure important information about the primary particle and the hadronic
interactions that rule the shower development. In fact, these two profiles
provide two different insights of the shower: the electromagnetic component
gives a measurement of the energy and the strength of the neutral pion channel;
while the muonic profile, being intimately related with the charged mesons
decays, can be used as a direct probe for the high energy hadronic
interactions.
In this work we explore the interplay between the electromagnetic and muonic
profiles, by analysing their phenomenologic behaviour for different primary
masses and energies, zenith angles, and also different high energy hadronic
interaction models. We have found that the muonic longitudinal profile at
production displays universal features similar to what is known for the
electromagnetic one. Moreover, we show that both profiles have new primary mass
composition variables which are fairly independent of the high energy hadronic
interaction model.
Finally we discuss how the information in the electromagnetic and the muonic
longitudinal profile can be combined to break the degeneracy between the
primary mass composition and the high energy hadronic physics.Comment: 5 pages, to appear in conference proceedings of International
Symposium on Very High Energy Cosmic Ray Interactions (ISVHECRI 2012),
Berlin, German
Universality of the muon component of extensive air showers
In extensive air shower experiments, the number of muons crossing a detector
at a given position, as well as their arrival time, arrival direction, and
energy, are determined by a more fundamental 3-dimensional distribution linked
to the hadronic core of the shower. Muons are produced high up in the
atmosphere after the decay of mesons in the hadronic cascade. The distributions
of production depth, energy, and transverse momentum of muons are enough to
fully predict the muon component of air showers in any particular observational
condition. By using air-shower simulations with the state-of-the-art hadronic
interaction models, the mentioned distributions at production are analyzed as a
function of zenith angle, primary mass, and hadronic interaction model, and
their level of universality is studied and assessed in an exhaustive manner for
the first time
The interplay between the electromagnetic and the muonic longitudinal profile at production
The electromagnetic and the muonic longitudinal profile at production enclosure important information about the primary particle and the hadronic interactions that rule the shower development. In fact, these two profiles provide two different insights of the shower: the electromagnetic component gives a measurement of the energy and the strength of the neutral pion channel while the muonic profile, being intimately related with the charged mesons decays, can be used as a direct probe for the high energy hadronic interactions.Peer Reviewe
Probing the spectrum at high- in proton-Air interactions at ultra-high energies
The average number of muons in air showers and its connection with shower
development has been studied extensively in the past. With the upcoming
detector upgrades, UHECR observatories will be able to probe higher moments of
the distribution of the number of muons. Here a study of the physics of the
fluctuations of the muon content is presented. In addition to proving that the
fluctuations must be dominated by the first interactions, we show that
low- tail of the shower-to-shower distribution of the number of muons
is determined by the high- region of the production cross-section of
neutral pions in the first interaction.Comment: Proceedings of Ultra High Energy Cosmic Rays 201
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