Literatura científica selecionada sobre o tema "Cosmic Rays, CALET, Interaction Point"

In this review, we first reassess the supernova remnant paradigm for the origin of Galactic cosmic rays in the light of recent cosmic-ray data acquired by the Voyager 1 spacecraft. We then describe the theory of light-element nucleosynthesis by nuclear interaction of cosmic rays with the interstellar medium and outline the problem of explaining the measured beryllium abundances in old halo stars of low metallicity with the standard model of the Galactic cosmic-ray origin. We then discuss the various cosmic-ray models proposed in the literature to account for the measured evolution of the light elements in the Milky Way, and point out the difficulties that they all encounter. It seems to us that, among all possibilities, the superbubble model provides the most satisfactory explanation for these observations.

The logical inconsistency of quantum mechanics and general relativity can be avoided if the relativity principle fails for length scales smaller than the quantum coherence length for the vacuum state. This has dramatic consequences for the phenomenology of compact astrophysical objects. If we assume that at the Planck scale elementary particles interact via a universal four-point interaction and baryon number conservation is violated, then nucleons approaching an event horizon surface can disintegrate into gamma rays and high energy leptons. Integrating the Altarelli–Parisi equations to find the Planck scale parton distribution function for a nucleon, we find that nucleon decays produce a fluorescence gamma ray spectrum strikingly similar to that observed for cosmic gamma ray bursts.

Abstract Upcoming neutrino telescopes may discover ultra-high-energy (UHE) cosmic neutrinos, with energies beyond 100 PeV, in the next 10–20 years. Finding their sources would identify guaranteed sites of interaction of UHE cosmic rays, whose origin is unknown. We search for sources by looking for multiplets of UHE neutrinos arriving from similar directions. Our forecasts are state-of-the-art, geared at neutrino radio-detection in IceCube-Gen2. They account for detector energy and angular response, and for critical, but uncertain backgrounds. Sources at declination of -45° to 0° will be easiest to discover. Discovering even one steady-state source in 10 years would imply that the source has an UHE neutrino luminosity at least larger than about 1043 erg/s (depending on the source redshift evolution). Discovering no transient source would disfavor transient sources brighter than 1053 erg as dominant. Our results aim to inform the design of upcoming detectors.

The observed spectrum of ultra-high energy cosmic rays virtually guarantees the presence of ultra-high energy neutrinos due to their interaction with the cosmic microwave background. Every one of these neutrinos will point back to its source and, unlike cosmic rays, will arrive at the Earth unattenuated, from sources perhaps as distant as z =20. The neutrino telescopes currently under construction, should discover a handful of these events, probably too few for detailed study. In this talk I will describe how an array of VHF and UHF antennas embedded in a large salt dome, SalSA (Saltdome Shower Array) promises to yield a teraton detector (> 500 km3-sr) for contained neutrino events with energies above 1017 eV. Our simulations show that such a detector may observe several hundreds of these neutrinos over its lifetime. Our simulations also show how such interactions will provide high energy physicists with an energy frontier for weak interactions an order-of-magnitude larger than that of the LHC. The flavor ID capalities of SALSA, combined with the extreme L/E of these neutrinos, will provide a window on neutrino oscillations and decay times eight orders of magnitude higher than laboratory experiments. In addition to the latest simulation results, we describe progress on detectors and site selection.

AbstractThe vicinity of the Galactic center harbors many potential accelerators of cosmic rays (CR) that could shine in very-high-energy (VHE) γ-rays, such as pulsar wind nebulae, supernova remnants, binary systems and the central black hole Sgr A*, and is characterized by high gas density, large magnetic fields and a high rate of starburst activity similar to that observed in the core of starburst galaxies. In addition to these astrophysical sources, annihilation of putative WIMPs concentrated in the gravitational well could lead to significant high-energy emission at the Galactic center. The Galactic center region has been observed by atmospheric Cherenkov telescopes, and in particular by the H. E. S. S. array in Namibia for the last ten years above 150 GeV. This large data set, comprising more than 200 hours of observations, led to the discovery of a point-like source spatially compatible with the supermassive black hole Sgr A*, and to an extended diffuse emission, correlated with molecular clouds and attributed to the interaction of cosmic rays with the interstellar medium. Over the same time period, two starburst galaxies, namely M 82 and NGC 253, were detected at TeV energies after very deep exposures. Results from these ten years of observations of the Galactic center region and starburst galaxies at TeV energies are presented, and implications for the various very-high-energy emission mechanisms are discussed.

SPD (Spin Physics Detector) collaboration proposes to install a universal setup in the second interaction point of the NICA collider under construction (JINR, Dubna) to study the spin structure of the proton and deuteron. It plans to carry out research of spin-related phenomena with polarized proton and deuteron beams at a collision energy up to 27 GeV and a luminosity up to 1032 cm−2 s−1. MiniSPD stand is manufactured as a setup for testing SPD detector prototypes with cosmic muons at LHEP. It allows to carry out checkout of the Data Acquisition System (DAQ), the Detector Control System (DCS). Young physicists and students working at this test bench gain experience of work with real detectors of the future SPD setup. In this report, we give some information about the basic tasks of SPD projects. The results of simulation and comparison with data on cosmic rays at this stand for three modules of silicon plates are also presented.

Photographs of double Sun lead in paper that it took off with Prohodnaja Griva of Gornyy Altay (near c. Belokurikha). Evidences of approaching second Sun – Nemesis to our Shine. Influence of Nemesis on the cosmic events in Sun system are very impression that its testify about interaction of two stars and influence second Sun on the planets of Sun system. Powerful emissions of plasma in view concentration rays with side of our Sun and separation blue spectrums clots with Nemesis that it point on the essential helium component. Myself Nemesis can to be carry to class B – white-blue giants. Anomaly movements of magnet poles of Earth call by impact of Nemesis and can be result to reserve polarity on the Earth.

(1) Pions produced in the development of extended atmospheric cosmic ray air showers subsequently decay to muons. The measured yield of those muons is generally underestimated by current phenomenological models and event generators optimized for cosmic ray physics. The importance of those disagreements motivates the feasibility studies for testing these models at the Large Hadron Collider (LHC) energies, at the highest center-of-mass energies achievable in a laboratory. The interaction of a nucleus and a virtual pion created in a charge exchange reaction at the LHC is a similar process to those contributing to the development of air showers in case of cosmic rays. The crucial problem of such an analysis is the selection of charge exchange events with the highest possible efficiency and high purity from proton–proton collisions at the LHC. (2) For this we consider distributions of various measurable quantities given by event generators commonly used in cosmic ray physics. (3) We examine the expected distributions of energy deposited in different calorimeters of an LHC experiment. We consider the geometrical acceptance and energy resolution of the detectors at the Compact Muon Solenoid (CMS) experiment, as an example. We determine a working point cut from the various options for event selection, and compare signal and background predictions using different models for a representative simple observable, such as average transverse momentum or charge particle yield. (4) A set of event selection cuts along these considerations is proposed, with the aim of achieving optimal efficiency and purity.

Abstract. Up until the recent past, it was generally believed that the solar wind termination shock (TS) is the favourite site to accelerate ions from the keV- to the MeV- energy levels by means of Fermi-1 processes. When Voyager 1 was crossing the TS at the end of 2004, the registrations of this spacecraft showed, however, that beyond the shock passage fluxes of anomalous cosmic rays kept increasing with time. This obviously called for an acceleration site further downstream of the shock in the heliosheath which had not been identified before. In this paper we thus investigate the process of energy diffusion due to wave-particle interactions (Fermi-2) operating on pick-up ions which are convected downstream of the TS with the subsonic solar wind. We investigate the continuous effect of stochastic acceleration processes suffered by pick-up ions at their interaction with heliosheath turbulences, while they are slowly convected with the subsonic solar wind towards the heliotail. As we can show, the inner heliosheath region, with an extent of about 100 AU around the solar wind stagnation point, is specifically favourable for the energy processing of pick-up ions by Fermi-2 processes up to MeV energies. In addition, we claim that this region is the origin of multiply-charged anomalous cosmic ray particles that have been registered in recent times.

Taiwan astroparticle radiowave observatory for geo-synchrotron emissions (TAROGE) is an antenna array on the high mountains of Taiwan’s east coast for the detection of ultra-high energy cosmic rays (UHECRs) in an energy above [Formula: see text] eV. The antennas point toward the ocean to detect radiowave signals emitted by the UHECR-induced air-shower as a result of its interaction with the geomagnetic field. Looking down from the coastal mountain, the effective area is enhanced by collecting both direct-emission as well as the ocean-reflected signals. This instrument also provides the capability of detecting earth-skimming tau-neutrino through its subsequent tau-decay induced shower. In order to prove the detection concept, initial two stations were successfully built at 1000 m elevation near Heping township, Taiwan, in 2014–2015. Each station consists of 12 log-periodic dipole array antennas for 110–300 MHz. The stations have been operating smoothly for radio survey and optimization of instrumental parameters. In this report, we discuss the design of TAROGE, the performance of the prototype station and the future prospect.

At present, Astro-particle Physics is one of the most interesting and alive fields in experimental physics. Direct measurements of cosmic rays will help answering many open questions about the sources and the processes of acceleration and propagation in the interstellar medium of high-energy particles (from GeV to PeV energy scale). For example, the measurement of both light and heavy nuclei spectra and their relative abundances for energies of tens of TeV/nucleon is one of the main topic to understand acceleration and propagation mechanisms in our Galaxy. The CALorimetric Electron Telescope (CALET) is a Japanese-led international space mission by JAXA (Japanese Aerospace Agency) in collaboration with the Italian Space Agency (ASI) and NASA, designed to perform precise measurements of high energy cosmic rays. CALET reached the ISS on August 24th , 2015 and started a campaign of scientific observations on October 13th the same year. After the first two-year period of the mission, an extension has been approved for additional three years. The broad scientific program of this space-based experiment includes many topics: the detection of possible nearby sources of high energy electrons; searches for signatures of dark matter in the spectra of electrons and γ rays; monitoring gamma-ray transients and solar modulation; long exposure observations of cosmic nuclei from proton to iron and trans-iron elements; measurements of the cosmic-ray relative abundances and secondary-to-primary ratios. The detector is composed by a Total Absorption Shower Calorimeter (TASC), an homogeneous calorimeter with a thickness of 27 radiation length (corresponding to 1.2 interaction length), a sampling IMaging Calorimeter (IMC) that adds 3 radiation length to the total thickness of the instrument and a CHarge Detector (CHD) for the identification of nuclear species in a wide dynamic range up to Z=40. The TASC detector has the function of measuring all the energy deposited by crossing particles. The IMC with its fine granularity allows for the reconstruction of the incident direction of particles with high angular resolution. This thesis illustrates the study on light nuclear components (such as protons and helium nuclei) with the aim to reconstruct the interaction vertex in the CALET detector. In addition to a previously developed algorithm for the reconstruction of the interaction point inside the IMC, a completely new one has been developed and tested for the TASC detector. Knowing with high precision the starting point of a shower inside the IMC detector is of fundamental importance for the CALET experiment because it allows for a redundant measurement of the charge of incoming particles with the IMC detector, in addition to the independent one provided by the CHD. Studying instead the interaction taking place in the depth of the TASC can help to understand whether those events have to be taken into account for flux measurements. The first chapter of this thesis is dedicated to a review of cosmic-ray physics with particular attention to acceleration and propagation mechanisms. Chapter 2 describes the CALET detector in detail, summarizes the architecture of the trigger system, provides the acceptance definition, and underlines the expected performance of the CHD detector, the electron/proton separation and the tracking reconstruction. Chapter 3 introduces the main scientific objectives of the CALET mission anticipating the expected measurements after five years of data taking. The original work of this thesis is described in chapters 4 and 5. The former contains the description of the interaction point reconstruction inside CALET while the latter shows how the potentiality of the algorithm can be exploited to observe energy deposits inside the TASC detector. Last, chapter 6 summarizes the results obtained by CALET after two years of data taking.