scholarly journals BOUNDS ON DIRECT COUPLINGS OF SUPERHEAVY METASTABLE PARTICLES TO THE INFLATON FIELD FROM ULTRA HIGH ENERGY COSMIC RAY EVENTS

2002 ◽  
Vol 17 (33) ◽  
pp. 2179-2188 ◽  
Author(s):  
A. H. CAMPOS ◽  
L. L. LENGRUBER ◽  
R. ROSENFELD ◽  
H. C. REIS ◽  
R. SATO
Keyword(s):  
Cosmic Rays ◽  
Early Universe ◽  
Cosmic Ray ◽  
High Energy ◽  
Ultra High Energy ◽  
Top Down ◽  
Inflaton Field ◽  
High Energy Cosmic Rays ◽  
Decay Products

Top-down models for the origin of ultra high energy cosmic rays (UHECR's) propose that these events are the decay products of relic superheavy metastable particles, usually called X particles. These particles can be produced in the reheating period following the inflationary epoch of the early Universe. We obtain constraints on some parameters such as the lifetime and direct couplings of the X-particle to the inflaton field from the requirement that they are responsible for the observed UHECR flux.

scholarly journals High energy cosmic ray interactions and UHECR composition problem

2019 ◽  
Vol 210 ◽  
pp. 02001
Author(s):  
Sergey Ostapchenko
Keyword(s):  
Experimental Data ◽  
Monte Carlo ◽  
Cosmic Rays ◽  
Cosmic Ray ◽  
High Energy ◽  
Ultra High Energy ◽  
Hadronic Interactions ◽  
High Energy Cosmic Rays ◽  
Cosmic Ray Interactions ◽  
Composition Problem

The differences between contemporary Monte Carlo generators of high energy hadronic interactions are discussed and their impact on the interpretation of experimental data on ultra-high energy cosmic rays (UHECRs) is studied. Key directions for further model improvements are outlined. The prospect for a coherent interpretation of the data in terms of the UHECR composition is investigated.

scholarly journals COLOR GLASS CONDENSATE IN BRANE MODELS OR DON'T ULTRA HIGH ENERGY COSMIC RAYS PROBE 1015eV SCALE?

2005 ◽  
Vol 20 (06) ◽  
pp. 419-440 ◽  
Author(s):  
HOURI ZIAEEPOUR
Keyword(s):  
Cosmic Rays ◽  
Extra Dimension ◽  
Cosmic Ray ◽  
High Energy ◽  
Effective Density ◽  
Color Glass ◽  
Color Glass Condensate ◽  
Ultra High Energy ◽  
High Energy Cosmic Rays ◽  
Brane Models

In a previous work1 we have studied the propagation of relativistic particles in the bulk for some of the most popular brane models. Constraints have been put on the parameter space of these models by calculating the time delay due to propagation in the bulk of particles created during the interaction of Ultra High Energy Cosmic Rays (UHECRs) with protons in the terrestrial atmosphere. The question was, however, raised that probability of hard processes in which bulk modes can be produced is small and consequently, the tiny flux of UHECRs cannot constrain brane models. Here we use Color Glass Condensate (CGC) model to show that effects of extra dimensions are visible not only in hard processes when the incoming photon/parton hits a massive Kaluza–Klein mode but also through the modification of soft/semi-hard parton distribution. At classical level, for an observer in the CM frame of UHECR and atmospheric hadrons, color charge sources are contracted to a thin sheet with a width inversely proportional to the energy of the ultra energetic cosmic ray hadron and consequently they can see an extra dimension with comparable size. Due to QCD interaction, a short life swarm of partons is produced in front of the sheet and its partons can penetrate to the extra-dimension bulk. This reduces the effective density of partons on the brane or in a classical view creates a delay in the arrival of the most energetic particles if they are reflected back due to the warping of the bulk. In CGC approximation the density of swarm at different distances from the classical sheet can be related and therefore it is possible (at least formally) to determine the relative fraction of partons in the bulk and on the brane at different scales. Results of this work are also relevant to the test of brane models in hadron colliders like LHC.

scholarly journals CODALEMA: A COSMIC RAY AIR SHOWER RADIO DETECTION EXPERIMENT

2006 ◽  
Vol 21 (supp01) ◽  
pp. 192-196 ◽  
Author(s):  
D. ARDOUIN ◽  
A. BELLETOILE ◽  
D. CHARRIER ◽  
R. DALLIER ◽  
L. DENIS ◽  
...  
Keyword(s):  
Cosmic Rays ◽  
Cosmic Ray ◽  
High Energy ◽  
Ultra High Energy ◽  
Air Showers ◽  
Detection Experiment ◽  
Transient Signals ◽  
High Energy Cosmic Rays ◽  
Air Shower ◽  
Radio Detection

The CODALEMA experimental device currently detects and characterizes the radio contribution of cosmic ray air showers : arrival directions and electric field topologies of radio transient signals associated to cosmic rays are extracted from the antenna signals. The measured rate, about 1 event per day, corresponds to an energy threshold around 5.1016eV. These results allow to determine the perspectives offered by the present experimental design for radiodetection of Ultra High Energy Cosmic Rays at a larger scale.

scholarly journals Ultra High Energy Cosmic Rays Spectra in Top-Down models

2004 ◽  
Vol 136 ◽  
pp. 319-326 ◽  
Author(s):  
R. Aloisio ◽  
V. Berezinsky ◽  
M. Kachelrieß
Keyword(s):  
Cosmic Rays ◽  
High Energy ◽  
Ultra High Energy ◽  
Top Down ◽  
High Energy Cosmic Rays

scholarly journals Origins of Extragalactic Cosmic Ray Nuclei by Contracting Alignment Patterns induced in the Galactic Magnetic Field

2019 ◽  
Vol 210 ◽  
pp. 04004
Author(s):  
Martin Erdmann ◽  
Lukas Geiger ◽  
David Schmidt ◽  
Martin Urban ◽  
Marcus Wirtz
Keyword(s):  
Magnetic Field ◽  
Cosmic Rays ◽  
Cosmic Ray ◽  
High Energy ◽  
Ultra High Energy ◽  
Galactic Magnetic Field ◽  
High Energy Cosmic Rays ◽  
Novel Approach ◽  
Astrophysical Scenario ◽  
The Individual

We present a novel approach to search for origins of ultra-high energy cosmic rays. In a simultaneous fit to all observed cosmic rays we use the galactic magnetic field as a mass spectrometer and adapt the nuclear charges such that their extragalactic arrival directions are concentrated in as few directions as possible. During the fit the nuclear charges are constraint by the individual energy and shower depth measurements. We show in a simulated astrophysical scenario that source directions can be reconstructed even within a substantial isotropic background.

scholarly journals ULTRA HIGH ENERGY COSMIC RAYS: ORIGIN AND PROPAGATION

2010 ◽  
Vol 25 (18) ◽  
pp. 1467-1481 ◽  
Author(s):  
TODOR STANEV
Keyword(s):  
Cosmic Rays ◽  
Gamma Rays ◽  
Cosmic Ray ◽  
High Energy ◽  
Ultra High Energy ◽  
Ultrahigh Energy ◽  
High Energy Cosmic Rays ◽  
Astrophysical Objects ◽  
Ultrahigh Energy Cosmic Rays ◽  
The Universe

We introduce the highest energy cosmic rays and briefly review the powerful astrophysical objects where they could be accelerated. We then introduce the interactions of different cosmic ray particles with the photon fields of the Universe and the formation of the cosmic ray spectra observed at Earth. The last topic is the production of secondary gamma rays and neutrinos in the interactions of the ultrahigh energy cosmic rays.

scholarly journals Additional sources of ionization in the early universe and the 21cm line

2006 ◽  
Vol 2 (14) ◽  
pp. 267-267
Author(s):  
Evgenii O. Vasiliev ◽  
Yuri A. Shchekinov
Keyword(s):  
Dark Matter ◽  
Cosmic Rays ◽  
Early Universe ◽  
High Energy ◽  
Ultra High Energy ◽  
Radio Telescopes ◽  
High Energy Cosmic Rays ◽  
Neutral Gas ◽  
Decaying Dark Matter

AbstractWe consider the influence of decaying dark matter particles and ultra-high energy cosmic rays (UHECRs) on the ability of neutral gas at redshifts z = 10-50 to emit and absorb in the 21cm line. We show that the signal in 21 cm is sensitive to properties of decaying particles and UHECRs, and conclude that future radio telescopes (LOFAR, LWA and SKA) are able not only to detect 21cm signal originated from decaying particles and UHECRs, but discriminate between them as well.

Propagation of Ultra-High Energy Cosmic Rays in Extragalactic Magnetic Fields

Open Physics ◽  
2004 ◽  
Vol 2 (2) ◽  
Author(s):  
Tadeusz Wibig
Keyword(s):  
Cosmic Rays ◽  
Magnetic Fields ◽  
Cosmic Ray ◽  
High Energy ◽  
Source Model ◽  
Energy Spectra ◽  
Single Source ◽  
Ultra High Energy ◽  
High Energy Cosmic Rays ◽  
Open Question

AbstractIn this paper we will discuss the problem of Ultra High Energy Cosmic Rays (UHECR) and show that the idea of a Single Source Model established by Erlykin and Wolfendale (1997) to explain the features seen in cosmic ray energy spectra around the 1015 eV region can be successfully applied also for the much higher energies. The propagation of UHECR (of energies higher than 1019 eV) in extragalactic magnetic fields can no longer be described as a random walk (diffusion) process and the transition to rectilinear propagation gives a possible explanation for the so-called Greisen-Zatzepin-Kuzmin (GZK) cut-off which still remains an open question after almost 40 years. A transient “single source” located at a particular distance and producing UHECR for a finite time is the proposed solution.

scholarly journals ACTIVE GALACTIC NUCLEI: SOURCES FOR ULTRA HIGH ENERGY COSMIC RAYS

2009 ◽  
Vol 18 (10) ◽  
pp. 1577-1581 ◽  
Author(s):  
P. L. BIERMANN ◽  
J. K. BECKER ◽  
L. CARAMETE ◽  
L. GERGELY ◽  
I. C. MARIŞ ◽  
...  
Keyword(s):  
Cosmic Rays ◽  
Radio Galaxy ◽  
Galactic Nuclei ◽  
Cosmic Ray ◽  
High Energy ◽  
Galactic Cosmic Rays ◽  
Ultra High Energy ◽  
Heavy Nuclei ◽  
High Energy Cosmic Rays ◽  
Relativistic Jet

Ultra high energy cosmic ray events presently show a spectrum, which we interpret here as galactic cosmic rays due to a starburst, in the radio galaxy Cen A which is pushed up in energy by the shock of a relativistic jet. The knee feature and the particles with energy immediately higher in galactic cosmic rays then turn into the bulk of ultra high energy cosmic rays. This entails that all ultra high energy cosmic rays are heavy nuclei. This picture is viable if the majority of the observed ultra high energy events come from the radio galaxy Cen A, and are scattered by intergalactic magnetic fields across much of the sky.

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