Studying the muon and hadron components of extensive air showers with the Carpet-2 array

The method of separating muons and hadrons recorded by the Muon Detector of the Carpet-2 air shower array of Baksan Neutrino Observatory (Institute for Nuclear Research, Russian Academy of Sciences) is described. The results of studying characteristics of the muon and hadron components of extensive air showers (EAS) with N _e ≥ 10⁵ are presented. For the range of distances 40–55 m from shower axes the numbers of hadrons with energies higher than 30 GeV and muons with energies above 1 GeV are obtained as functions of the shower size N _e .     

Investigating hadronic cores of exstensive air showers at the CARPET-2 array

Characteristics of the hadronic component of exstensive air shower (EAS) trunks are investigated at the CARPET-2 array of the Baksan Neutrino Observatory, Institute for Nuclear Research, Russian Academy of Sciences. In this work, we study showers with axes that located within its muon detector (MD). We discuss the procedure for selecting such showers in our experiment. The relationship between the number of thermal neutrons detected by heat detectors installed in the muon detector’s tunnel and the total energy of a cascade generated by hadrons in the magnetic detector’s absorbent matter is presented.     

Reestimation of the energy of extensive air showers at the Yakutsk EAS array with the CORSIKA package

The responses of ground and underground muon scintillation detectors of the Yakutsk extensive air shower (EAS) array from primary particles with the energy E ₀ ≥ 10¹⁷ eV have been calculated within the QGSJET-01-d, QGSJET-II-04, SIBILL, and EPOS-LHC models with the CORSIKA package. A new estimate obtained for E ₀ is lower by a factor of about 1.41 than that previously obtained within the calorimetric method for EASs.     

Neutron multiplicity: Local hadronic showers and extensive air showers

A detailed analysis of events with neutron multiplicity M = 3−30 on neutron monitors (NMs) in Barentsburg (Spitsbergen), Baksan (North Caucasus), and Apatity (Murmansk region) is performed on the data obtained using a unique new data collection system. It is now possible for the first time to register local showers in cosmic rays on NMs and to investigate their structure with a high precision. Multiplicity on NMs is simulated using the GEANT4 Monte Carlo toolkit. Local hadronic cascades in the atmosphere with transverse sizes of 1 to 6 m were observed for the first time using the NM data. NM multiplicity generated by EAS hadronic cascades is studied on the data set on coupling NMs with the CARPET EAS facility.     

Low-energy muons in extensive air showers (EAS)

Summary A small air shower array of 21 detectors in conjunction with two shielded muon magnetic spectrographs has been operated for detection of muons of momentum in the range (2÷500) GeV/c at a geomagnetic latitude of 26^o 45′ N at North Bengal University Campus. The array is sensitive to air showers initiated by cosmic-ray primaries of energy in the range (10¹⁴÷10¹⁶) eV. The initial results on muons with a comparison of other recent measurements have been given to infer information on the characteristics of high-energy interaction. An evaluation on the Monte Carlo simulation and observational data on muons in air showers have also been given to indicate the present status of the study of muons in air showers.

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Riassunto Si utilizza un piccolo insieme di ventuno rivelatori di sciami cosmici congiunto a due spettrografi muonici magnetici schermati per rilevare muoni con momento nell'intervallo (2÷500) GeV/c ad una latitudine geomagnetica di 26^o 45′ N al North Bengal University Campus. L'insieme è sensibile a sciami cosmici iniziati da primarie con energia nell'intervallo (10¹⁴÷10¹⁶) eV. Si effettua un confronto dei risultati iniziali sui muoni con altre misure recenti per riferire informazioni sulle caratteristiche dell'interazione ad alta energia. Si dà una valutazione della simulazione di Monte Carlo e dei dati osservativi sui muoni negli sciami cosmici per indicare lo stato attuale dello studio dei muoni nei raggi cosmici.

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Реэюме НеболъшАя из 21 детектора атмосферных яяивней, соедненная с двумя мюонными магнитными спектрогафами, используется для детектектирования мюонов с импульсами в области (2÷500) ГзВ/с на геомагнитной широте 26° 45′ N в камрусе Северного ьенгалъского университета. Детектируюшая система чувстви-телъна к атмосферным ливням, образованным космическими частицами с знергиями в интервале (10¹⁴÷10¹⁶) зВ. Сравнение полученных резулътатов с данными других недавних измерений позволяет получитв информациу о характеристиках взаимо-действий при оченъ вюсоких знергиях. Проводится такзе сравнение моделирования по методу Монте Карло с данными наблюдений для мюонов в атмосферных ливнях.

     

Measurements of the characteristics of low-energy extensive air showers (EAS)

Summary New results on the characteristics of smaller air showers in the size range 10⁴÷10⁵ particles detected by a closely packed detector array are presented. The characteristics of showers such as local age parameter, average age parameter, electron lateral distribution and size spectrum have been determined and a critical comparison of the existing theoretical electron lateral distribution in air showers is given to indicate the present status in relation to the present experimental data on lowenergy EAS.

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Riassunto Si presentano nuovi risultati sulle caratteristiche degli sciami cosmici piú piccoli nell'intervallo di dimensione da 10⁴ a 10⁵ particelle rivelate da un insieme di rivelatori molto compatti. Si determinano le caratteristiche dello sciame come i parametri di età locale, età media, la distribuzione laterale di elettroni e lo spettro di dimensione e si fa un confronto critico con la distribuzione laterale teorica attuale degli elettroni negli sciami cosmici per indicare lo status attuale in relazione ai dati sperimentali attuali sugli EAS a bassa energia.

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Резюме Приводятся новые результаты о характеристиках небольших атмосферных ливней в области 10⁴÷10⁵ частиц, которые были зарегистированы с помощью плотноупакованной антенной решетки детыeкторов. Были определны такие характеристики ливней, как локальный возрастной параметр, поперечное распреденение электронов и спектр размеров. Продится критическое сравнение существующего теоретического поперечного распределения электронов в атмосферных ливнях с полученными экспериментальными данными для низкоэнергетических широких атмосферных ливней.

     

Muon production in extensive air showers and its relation to hadronic interactions

In this work, the relation between muon production in extensive air showers and features of hadronic multiparticle production at low energies is studied. Using CORSIKA, we determine typical energies and phase space regions of secondary particles which are important for muon production in extensive air showers and confront the results with existing fixed target measurements. Furthermore possibilities to measure relevant quantities of hadron production in existing and planned accelerator experiments are discussed.     

Astrophysical and structural peculiarities of extensive air showers with energy E 0 ≥ 1017 eV from Yakutsk EAS array data

The astrophysical characteristics of primary cosmic rays (PCRs) and the structure of extensive air showers (EASs) with energy E ₀ ≥ 10¹⁷ eV are simultaneously analyzed using the Yakutsk EAS array data acquired in the period 1974–2005. Enhanced and reduced particle fluxes are shown to come from the disk of the Supergalaxy (the Local Supercluster of galaxies) at E ₀ ≥ 5 × 10¹⁸ eV and E ₀ ≤ (2?3) × 10¹⁸, respectively. The development of air showers with E ₀ ≥ (3?5) × 10¹⁸ eV differs significantly from that at lower energies. This is interpreted as a manifestation of the possible interaction between extragalactic PCRs and the matter of this spatial structure.     

Multiple penetrating particles with narrow separation associated with extensive air showers (EAS)

An experiment has been carried out at a vertical depth of 580 m.w.e. at Kolar Gold Fields, to investigate various characteristics of energetic muons (E _mln ⋍ 150 GeV) associated with extensive air showers (EAS). Double parallel penetrating particles with narrow separations (<1m) have an exponential decoherence distribution withe-folding separation of ⋍ 25 cm.     

Radio emission of extensive air showers at microwave frequencies

It is found that the power of the incoherent radiation of ionization electrons of an extensive air shower in the frequency range of 150 GHz is more than 10^–24 W/m²Hz, with the shower energy ~10¹⁸ eV at a distance of 5 km from its axis. This means that, unlike fluorescent detectors, a radio telescope with an effective area of more than 300 m² can monitor the trajectory of showers with an energy higher than 10¹⁸ eV at any time of the day regardless of the weather. The spectrum maximum near the frequency of 150 GHz is roughly three orders of magnitude higher than the value experimentally measured in the characteristic band (~5-10 GHz).     

Neutrons in extensive air showers

The main properties of the so-called neutron bursts produced by the passage of extensive air showers (EASs) through a detector array and the properties of these EASs are considered using the experiments that are being or have been carried out previously with the Carpet-2 array at Baksan Neutrino Observatory of the Institute for Nuclear Research, Russian Academy of Sciences, and at Cosmic-Ray Station of UNAM in Mexico as examples. We show that no exotic processes are required to explain the nature of neutron bursts. Based on a working prototype of the previously proposed MULTICOM array, we also show that this phenomenon can be successfully used in studying the EAS hadronic component and that adding special thermal neutron detectors can improve significantly the capabilities of the array for EAS study.     

Neutrons in extensive air showers

The first results of measurements of the thermal-neutron flux in extensive air showers (EASs) using an unshielded scintillation thermal-neutron detector in the Multicom prototype array at the Baksan Neutrino Observatory of the Institute for Nuclear Research are reported. The operating capacity of the new method for studying the EAS hadron component via detection of thermal neutrons and good prospects of this method are demonstrated.     

Networks in extensive air showers

Extensive air showers are produced when high energy cosmic rays or γ$\gamma$-rays enter from the top of the atmosphere. Extensive air showers are multi-fractal in nature and in this paper we explore the topological properties of these showers. We show that the topology of extensive air showers has an exponential distribution which may arise due to the inherent tree structure character of its passage in the atmosphere.     

Kaluza-Klein gravitons at the LHC and in extensive air showers

The small curvature option of the Randall-Sundrum model with two branes is considered which has almost continuous spectrum of low-mass Kaluza-Klein gravitons. It is shown that gravity effects related with these excitations can be detected in double diffractive events at the LHC and in inclined air showers induced by interactions of cosmic neutrinos with atmospheric nucleons at ultra-high energies.     

Observation of double extensive air showers

Double extensive air showers were studied at the Tien Shan high-mountain scientific station of the Lebedev Physical Institute using two different installations. One measured the electron-photon shower component, the other measured Cherenkov radiation. Double showers separated by a time interval of ～100 ns were detected by both setups. The frequency of the occurrence of such showers in each setup is analyzed. It is shown that these frequencies are identical when observing vertical showers (the zenith angle ? < 60°).     

Delayed muons in extensive air showers and double-front showers

The results of a long-term experiment performed in the period between 1995 and 2006 with the aid of the MUON-T underground (20 mwe) scintillation facility arranged at the Tien Shan mountain research station at an altitude of 3340 m above sea level are presented. The time distribution of delayed muons with an energy in excess of 5 GeV in extensive air showers of energy not lower than 106 GeV with respect to the shower front was obtained with a high statistical significance in the delay interval between 30 and 150 ns. An effect of the geomagnetic field in detecting delayed muons in extensive air showers was discovered. This effect leads to the asymmetry of their appearance with respect to the north-south direction. The connection between delayed muons and extensive air showers featuring two fronts separated by a time interval of several tens of to two hundred nanoseconds is discussed. This connection gives sufficient grounds to assume that delayed muons originate from the decays of pions and kaons produced in the second, delayed, front of extensive air showers.     

Portion of muons with a threshold energy above 1 GeV in extensive air showers with ultra-high energies,according to the Yakutsk EAS array data

Characteristics of the muon component in extensive air showers and the fluctuations of muons are considered. In this work, we compare experimental data with computations performed for various models of the hadron interactions of protons and iron nuclei. The aim of this analysis is to obtain information on the mass composition of cosmic rays in an ultra-high energy region.     

On the angular distribution of extensive air showers

Angular distributions of extensive air showers with different number of charged particles in the range 2.5 × 10⁵–4 × 10⁷ are derived using the experimental data obtained with the EAS MSU array. Possible approximations of the obtained distributions with different empiric functions available in literature, are analyzed. It is shown that the exponential function provides the best approximation of the angular distributions in the sense of the χ² criterion.     

Signals in the underground scintillation detectors of the Yakutsk array from muons of extensive air showers

A model of the underground part of the Yakutsk array was developed. The signals from muon scintillation detectors were calculated using the GEANT4 code within this model. It was shown that the signals strongly fluctuate and may be several times higher that the mean ionization energy losses by a single muon. These large losses imitate high muon multiplicity in the case of a low muon density. It was also shown that there are many gamma particles near the shower axis, which significantly contribute to signals in underground detectors and thus make data interpretation difficult.