July 29, 2015 to August 6, 2015
World Forum
Europe/Amsterdam timezone

Probing the pseudorapidity region eta > 7 with the ARGO - YBJ detector

Aug 1, 2015, 3:30 PM
Amazon Foyer (World Forum)

Amazon Foyer

World Forum

Churchillplein 10 2517 JW Den Haag The Netherlands
Board: 198
Poster contribution CR-EX Poster 2 CR


michele iacovacci (INFN)


By means of the analog readout, the ARGO-YBJ experiment is able to image the very hot region of the shower core up to particle density of many 10^4/m^2. Exploiting this feature the number of particles within 10 m from the core and the local age have been carefully studied. This cascade region is mainly developed from particles produced in the first interactions with pseudorapidity eta > 7, an angular region still out of the reach of the accelerator experiments. We find a systematic shift of the measure d local age by $\sim$ 0.15-0.20 with respect to the MC expectation, by assuming primary fluxes and composition as given by the Hoerandel model and hadronic interactions as described by QGSJET2. This effect cannot be taken into account by any instrumental effect neither by reconstruction biases. Possible explanations of this result involve both the features of the hadronic interaction as well as the elemental composition of the primary cosmic rays in the energy range between 50 TeV and 5 PeV.
Registration number following "ICRC2015-I/" 817
Collaboration ARGO-YBJ

Primary author

Stefano Mastroianni (INFN, sec. Naples)


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