Hadron-rich cosmic-ray families detected by emulsion chamber.

The observed hadrons in excess, larger-than-expected charged mesons (pions) in cosmic-ray families detected in emulsion chamber experiment at mountain altitude (5220 m above sea level) and produced in cosmic-ray hadronic interaction not far from PeV energy region are here studied. The hypothesis that these extra hadrons could be a bundle of surviving nuclear fragments (nucleons) is verified through a simulation method using a hybrid code composed by a superposition model to describe the number of interacting pairs of nucleon-nucleon in a nucleus-nucleus collision. Together with the UA5 algorithm to describe nucleon-nucleon collision, atmospheric propagation structure is also considered. A comparison between simulation output with experimental data shows that the surviving-nuclear-fragments hypothesis is not enough to explain non-pionic hadron excess, even if a heavy dominance composition in the primary flux is considered.108111341135

EXOTIC DIFFRACTIVE DISSOCIATION IN HADRONIC COLLISIONS

A full Monte-Carlo simulation of Centauro-like events is carried out using a model where these events are a result of isotropic decaying of ''exotic fireballs'' coherently produced in diffractive dissociation. The input testaments to the event generator are explained in detail and we find that the model predictions are in agreement with available data from emulsion chamber experiments. Centauro-type events at collider experiments are also reexamined and discussed within this context. We show that, at the extremely high energy region E(0) greater than or equal to 10(5) TeV, an exotic dominant channel is consistent with experimental data.5095732574

INELASTICITY IN NUCLEON-NUCLEON AND NUCLEON-NUCLEUS COLLISION

Full Monte Carlo simulation of nuclear interactions was performed for energy dependence study of the inelasticity for charged particles in nucleon-nucleon and nucleon-nucleus collision using collider experimental data (CERN and Fermilab) and two different types of interaction models (Fire Tube and Minijet) for parametrization of pseudo-rapidity density distribution at large values of the pseudo-rapidity (\eta\ > 5). It was found that for both parametrizations the inelasticity in ppBAR collision decreases when energy increases and for proton-air nucleus the inelasticity has also a moderate decrease with the energy. However for proton-nucleus the inelasticity has a strong sensitivity with the mass number of the nucleus. Using our calculations for charged particles and statistical criterions we estimate the energy dependence on the total inelasticity for proton-air nucleus; our results are in good agreement with results obtained using the relation K(p-air) = A(delta)K(ppBAR)(A = 14.5, delta = 0.1) where K(ppBAR) is obtained with experimental data of the UA7 Collaboration in the forward region.881536

Connection among spacecrafts and ground level observations of small solar transient events An overview of small solar transient events observed at ground

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)An overview of the results of the search for small solar transient events, in association with muon enhancements (deficits) registered at ground-level by the Tupi muon telescopes, is presented. Among the events, there are three interplanetary shocks and two solar flares of small scale whose X-ray emission flux is much smaller than 10(-5) W m(-2) at 1 AU (GOES-Tupi connection). Two of the interplanetary shocks are cataloged as corotating interaction region and the third shock is due to the passage of a CME (coronal mass ejection) ejecta (ACE and SOHO-Tupi connection) in the Earth's proximities. In most cases, the particles excess (deficit) coming from these events have only been observed with spacecraft instruments. However, the Tupi telescopes are located at sea level and within the South Atlantic Anomaly (SAA), a region where the shielding effect of the magnetosphere is not perfectly spherical and shows a 'dip'. This fact enables the muon telescopes to achieve a low rigidity of response to primary and secondary charged particles (>= 0.1 GV). Muon excesses (deficits) with significances above 4 sigma have been found. These events observed at ground admit a temporal correlation with solar transient events observed by spacecrafts, which suggests strongly a real connection between them. Details of these observations are reported.3141700177197Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CNPq [479813/2004 - 3, 476498/2007 - 4

gamma-hadron families sensitivity to disoriented chiral condensates

Presented in this study is a possible coherent emission of pions from a large domain of disoriented chiral condensate (DCC) in the leading particle region, through their influence on the development of the gamma-hadron families, initiated by cosmic ray particles in the atmosphere. The production rate of DCC's is obtained by using a phenomenological framework in the quenching approximation and is included in a Monte Carlo code. In this context, we have found, under the assumption of a ''normal'' proton dominant composition in the primary Bur, that the anomalous hadron-rich families, observed in the experimental data, can be reproduced. However, the production rate of DCC's obtained here is not enough to describe the global characteristics, such as the family flux, observed at mountain altitudes. The implications of these results are here discussed.5595834584

Search for disoriented chiral condensate in cosmic gamma-hadron families

We present a systematic study of the large asymmetries in neutral pion fraction distribution in high energy cosmic ray families (100 TeV<E-vis<700 TeV) detected at high mountain altitudes at Pamir (4300 m, 595 g/cm(2)). With this in mind we have constructed robust observables, ratios of factorial moments, in experimental and simulated families in a similar way. We have found that our experimental data do not exclude the possibility of a DCC formation mechanism in high energy interactions. [S0556-2821(99)06901-5].59

Observation of a muon excess following a gamma-ray burst event detected at the International Space Station

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)On April 24, 2012, at 16: 47: 14 UT, the Gas Slit Camera (GSC) of the Japanese Monitor of All-sky X-ray Image (MAXI) instrument on the International Space Station detected a short x-ray transient lasting about 34 seconds. The MAXI/GSC transient was most likely a gamma-ray burst (GRB), because of the high Galactic latitude, spectral hardness ratio, and the absence of known bright x-ray sources at the detected position. In addition, the MAXI/GSC transient GRB 120424A coordinates were in the field of view of the inclined Tupi muon telescope located at ground level (3 m above sea level) at (22.9 degrees W, 43.2 degrees S) in the South Atlantic Anomaly region. We report here that the Tupi telescope registered a muon excess with a signal significance 6.2 sigma within the MAXI/GSC transient time period. Assuming a power law function with a spectral index of gamma = -1.54 in the tail of the primary gamma-ray energy spectrum, we can conclude that the fluence obtained from the muon excess detected by the Tupi telescope is consistent with the preliminary value obtained by the MAXI team. This result agrees with an assumption that the muons were produced in photonuclear reactions in the Earth's atmosphere. In addition, we show also that the South Atlantic Anomaly region can be a favorable place at ground for the detection of the tail of the energy spectrum (the GeV counterpart) of some GRBs.8710Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CNPq [306605/2009-0, 01300.077189/2008-6]Fundacao de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ) [08458.009577/2011-81, E-26/101.649/2011

GAMMA-RAY BUNDLES AT THE CORES OF EXTENSIVE AIR SHOWERS AND PRIMARY COSMIC-RAY IDENTIFICATION

We present a useful clue to estimate the energy and chemical composition of the primary cosmic radiation between 10(14) and 10(17) eV. The method uses various kinds of quantities as measure by a hybrid detector, an emulsion chamber in the central part of an extensive air shower (EAS) array at mountain altitude. The characteristic features needed for the analysis are derived in detail through the Monte Carlo method. The procedure permits an analysis on individual events; it gives an estimation of the mass and energy of a primary nucleus initiating a shower. The estimation of the primary energy is with quite negligible ambiguity. We show that the EAS size measurement could be complementary to quantities as measured by an emulsion chamber detector to improve the accuracy of the primary cosmic ray identification.5294976498