https://doi.org/10.1140/epjp/i2018-11898-x
Regular Article
Search for long distance correlations between extensive air showers detected by the EEE network
1
Museo Storico della Fisica, Centro Studi e Ricerche Enrico Fermi, Roma, Italy
2
INFN and Dipartimento Interateneo di Fisica, Università di Bari, Bari, Italy
3
INFN and Dipartimento di Fisica, Università di Pisa, Pisa, Italy
4
INFN, Laboratori Nazionali di Frascati, Frascati (RM), Italy
5
INFN Gruppo Collegato di Siena and Dipartimento di Fisica, Università di Siena, Siena, Italy
6
INFN and Dipartimento di Fisica e Astronomia, Università di Bologna, Bologna, Italy
7
INFN and Dipartimento di Fisica, Università di Torino, Torino, Italy
8
INFN and Dipartimento di Fisica, Università di Cagliari, Cagliari, Italy
9
INFN and Dipartimento di Fisica, Università di Roma Tor Vergata, Roma, Italy
10
INFN and Dipartimento di Matematica e Fisica, Università del Salento, Lecce, Italy
11
INFN and Dipartimento di Fisica, Università di Salerno, Salerno, Italy
12
INFN, Laboratori Nazionali del Gran Sasso, Assergi (AQ), Italy
13
INFN, CNAF, Bologna, Italy
14
ICSC World Laboratory, Geneva, Switzerland
15
CERN, Geneva, Switzerland
16
JINR, Dubna, Russia
17
INFN and Dipartimento di Fisica, Università di Genova, Genova, Italy
18
INFN and Dipartimento di Fisica e Astronomia, Università di Catania, Catania, Italy
19
INFN Sezione di Catania and Dipartimento di Scienze Chimiche, Biologiche, Farmaceutiche e Ambientali, Università di Messina, Messina, Italy
20
INFN, Sezione di Bari, Bari, Italy
21
INFN, ASI Science Data Center, Roma, Italy
22
INFN and Dipartimento di Fisica, Università della Calabria, Cosenza, Italy
23
INFN Sezione di Catania and Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra, Università di Messina, Messina, Italy
* e-mail: Francesco.Riggi@ct.infn.it
Received:
11
August
2017
Accepted:
13
January
2018
Published online:
2
February
2018
A search for long distance correlations between individual Extensive Air Showers (EAS) detected by pairs of MRPC telescopes of the Extreme Energy Events (EEE) network was carried out. The search for an anomaly in these events is the purpose of our work. A dataset obtained by all the possible 45 pairs between 10 EEE cluster sites (hosting at least two telescopes), located at relative distances between 86 and 1200km, was analyzed, corresponding to an overall period of 3968 days time exposure. To estimate the possible event excess with respect to the spurious rate, the number of coincidence events was extracted as a function of the time difference between the arrival of the showers in the two sites, from s to the smallest time interval where events are still observed. The analysis was done taking into account both the time and orientation correlation between the showers detected by the telescope pairs. A few candidate events with unusually small time difference and angular distance were observed, with a p-value sensibly smaller than a confidence level of 0.05.
© Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature, 2018