Heavy Cosmic Ray Nuclei Research Articles

Inelastic Scattering of Dark Matter with Heavy Cosmic Rays

We investigate the impact of inelastic collisions between dark matter (DM) and heavy cosmic ray (CR) nuclei on CR propagation. We approximate the fragmentation cross-sections for DM-CR collisions using collider-measured proton-nuclei scattering cross-sections, allowing us to assess how these collisions affect the spectra of CR boron and carbon. We derive new CR spectra from DM-CR collisions by incorporating their cross-sections into the source terms and solving the diffusion equation for the complete network of reactions involved in generating secondary species. In a specific example with a coupling strength of b χ = 0.1 and a DM mass of m χ = 0.1 GeV, considering a simplified scenario where DM interacts exclusively with oxygen, a notable modification in the boron-to-carbon spectrum due to the DM-CR interaction is observed. Particularly, the peak within the spectrum, spanning from 0.1 to 10 GeV, experiences an enhancement of approximately 1.5 times. However, in a more realistic scenario where DM particles interact with all CRs, this peak can be amplified to twice its original value. Utilizing the latest data from AMS-02 and DAMPE on the boron-to-carbon ratio, we estimate a 95% upper limit for the effective inelastic cross-section of DM-proton as a function of DM mass. Our findings reveal that at m χ ≃ 2 MeV, the effective inelastic cross-section between DM and protons must be less than O(10−32)cm2 .

Testing the consistency of propagation between light and heavy cosmic ray nuclei * *Supported by the Joint Funds of the National Natural Science Foundation of China (U1738130)

One of the fundamental challenges in cosmic ray physics is to explain the nature of cosmic ray acceleration and propagation mechanisms. Owing to the precise cosmic ray data measured by recent space experiments, we can investigate cosmic ray acceleration and propagation models more comprehensively and reliably. In this paper, we combine the secondary-to-primary ratios and primary spectra measured by PAMELA, AMS02, ACE-CRIS, and Voyager-1 to constrain the cosmic ray source and transport parameters. The study shows that the data yield a medium-energy diffusion slope and a high-energy slope . The species place a looser constraint on but a tighter constraint on . The overlaps imply that heavy and light particles can provide compatible results at medium to high energies. Moreover, both the light and heavy nuclei indicate a consistent diffusion slope variation at GV. At low energies, significant disagreements exist between heavy and light elements. The boron-to-carbon ratio requires a much larger diffusion slope shift at approximately 4 GV or a stronger Alfvén velocity than the low-mass data. This indicates that the heavy and light particles may suffer different low-energy transport behaviors in the galaxy. However, a better understanding of the consistency/inconsistency between the heavy and light cosmic rays relies on more precise cross-sections, better constraints on correlations in systematic errors of data, a more accurate estimation of the galaxy halo size, and a more robust description of solar modulation during the reversal period of the heliospheric magnetic field.

Charge fragmentation in cosmic radiation – and the question of physical anomalons

Abstract Data analysis is carried out for four detector stacks composed of passive Lexan polycarbonate detectors exposed in space by the Ultra Heavy Cosmic Ray Experiment on board NASA’s Long Duration Exposure Facility. Scanning and analysis of the 0.21 m2 detector area resulted in the finding of 72 ultra heavy (68 ≤ Z ≤ 96) cosmic ray nuclei. About 15% of the cosmic ray nuclei show charge fragmentation within the detector stack of 5.6 g × cm–2. A detailed analysis of these fragmented cosmic ray nuclei is presented, including a discussion within the context of “physical anomalons”. This last term, describing a sub-set of all anomalon phenomena, is defined in the text.

Study of the Pallasite Radiation History by Track Analysis

This work was performed within the OLYMPIA experiment on the study of tracks of heavy and superheavy cosmic ray nuclei in olivine crystals from Marjalahti and Eagle Station pallasites. Depth distributions of the track formation rate for heavy cosmic ray nuclei in olivine crystals from pallasites of different pre-atmospheric sizes were obtained. The dependences obtained were used to analyze the data on the track density in olivine crystals from the Marjalahti pallasite. In three crystals, the track distribution with a high density gradient was detected, which indicates a complicated radiation history of the meteorite.

Measurements of Heavy Cosmic-Ray Nuclei Spectra with CALET on the ISS

CALorimetric Electron Telescope (CALET) has been accumulating data of high-energy cosmic rays on the International Space Station since August 2015. In addition to the primary observation of the all-electron spectra, CALET also measures the spectra of nuclei, their relative abundances and secondary-to-primary ratios to the highest energy region ever directly observed in order to investigate details of their origin and propagation in the galaxy. The CALET instrument consists of two layers of segmented plastic scintillators to identify the individual elements from Z = 1 to 40, a 3 radiation length thick tungsten-scintillating ber imaging calorimeter to obtain complementary charge and tracking information, and a 27 radiation length thick segmented PWO calorimeter to measure the energy. In this paper, the capability of CALET to perform nuclei measurements and preliminary energy spectra of heavy nuclei components using 962 days of data is presented.

A model of chemical etching of olivine in the vicinity of the trajectory of a swift heavy ion

Searching of superheavy elements, the charge spectra of heavy nuclei in Galactic Cosmic Rays was investigated within the OLYMPIA experiment using the database of etched ion tracks in meteorite olivine. Etching results in the formation of hollow syringe-like channels with diameters of 1–10μm along the trajectories of these swift heavy ions (SHI). According to the activated complex theory, the local chemical activity is determined by an increase of the specific Gibbs energy of the lattice stimulated by structure transformations, long-range elastic fields, and interatomic bonds breaking generated in the vicinity of the ion trajectory. To determine the dependencies of the Gibbs free energy increase in SHI tracks in olivine on the mass, energy and charge of a projectile, we apply a multiscale model of excitation and relaxation of materials in the vicinity of the SHI trajectory (SHI tracks). Effect of spreading of fast electrons from the ion trajectory causing neutralization of metallic atoms resulting in an increase of the chemical activity of olivine at long distances from the ion trajectory (up to 5μm) is estimated and discussed.

Very high energy antineutrinos from photo-disintegration of cosmic ray nuclei

The photo-disintegration of cosmic ray nuclei by starlight leads to the production of secondary antineutrinos. We have assumed that the flux of the ultrahigh energy cosmic ray nuclei near the Galactic plane region is the same as that observed near the earth and calculated the antineutrino flux produced from their photo-disintegration. The IceCube detector has measured the neutrino/antineutrino flux in the TeV–PeV energy range. Our calculated secondary antineutrino flux in the energy range of 10–100 TeV is found to be much less compared to the flux detected by the IceCube collaboration. The upper limit on the intensity of the radiation field in the extragalactic medium is much lower than that near the Galactic center. If we extend our formalism to the extragalactic medium the contribution from the photo-disintegration of ultrahigh energy cosmic ray heavy nuclei remains insignificant due to their very low flux.

A template method for measuring the iron spectrum in cosmic rays with Cherenkov telescopes

Understanding the sources, acceleration mechanisms, and propagation of cosmic rays is an active area of research in astro-particle physics. Measuring the spectrum and elemental composition of cosmic rays on earth can help solve this question. IACTs, while mainly used for γ-ray astronomy and indirect searches for dark matter, can make an important contribution here. In particular, they are able to distinguish heavy nuclei in cosmic rays from protons and lighter nuclei by exploiting the direct Cherenkov light emitted by charged particles high in the atmosphere. In this paper, a method to reconstruct relevant properties of primary cosmic ray particles from the Cherenkov light emitted by the primary particles and the air showers induced by them will be presented.

An observation‐based GCR model of heavy nuclei: Measurements from CRIS onboard ACE spacecraft

We present an observation‐based elemental Galactic Cosmic Ray (GCR) heavy nuclei spectra model, based on ACE/CRIS measurements. Then we extrapolate the spectra model to the lower energy range of ACE/SIS instrument. In addition, we compare the modeling results with both the CRIS and SIS measurements. The flux of lower energetic particles measured by SIS are despiked since there are Solar Energetic Particle (SEP) events. The good agreement between the modeling and the observation results, especially for the solar minimum, indicates the validity of our model in the energy range 30–500 MeV/nuc. Compared with two GCR radiation environment models, CRÈME96/Nymmik model and Badhwar & O'Neill model, our model can provide an improved fit to the GCRs spectra measured by ACE. Furthermore, our model is a phenomenological one, without consideration of the physical process during GCRs' propagating through the heliosphere. Therefore, it is more straightforward and applicable in practice. Finally, the model can reproduce and predict the GCR spectra in the past and future, respectively, based on the strong correlation between the model parameters and solar activity indicated by sunspot number.

MODELING PHOTODISINTEGRATION-INDUCED TeV PHOTON EMISSION FROM LOW-LUMINOSITY GAMMA-RAY BURSTS

Ultra-high-energy cosmic-ray heavy nuclei have recently been considered as originating from nearby low-luminosity gamma-ray bursts that are associated with Type Ibc supernovae. Unlike the power-law decay in long duration gamma-ray bursts, the light curve of these bursts exhibits complex UV/optical behavior: shock breakout dominated thermal radiation peaks at about 1 day, and, after that, nearly constant emission sustained by radioactive materials for tens of days. We show that the highly boosted heavy nuclei at PeV energy interacting with the UV/optical photon field will produce considerable TeV photons via the photodisintegration/photo-de-excitation process. It was later predicted that a thermal-like ?-ray spectrum peaks at about a few TeV, which may serve as evidence of nucleus acceleration. The future observations by the space telescope Fermi and by the ground atmospheric Cherenkov telescopes such as H.E.S.S., VERITAS, and MAGIC will shed light on this prediction.

Spacetime noncommutativity and ultrahigh energy cosmic ray experiments

If new physics were capable of pushing the neutrino-nucleon inelastic cross section 3 orders of magnitude beyond the standard model prediction, then ultrahigh energy (UHE) neutrinos would have already been observed at neutrino observatories. We use such a constraint to reveal information on the scale of noncommutativity (NC) ${\ensuremath{\Lambda}}_{\mathrm{NC}}$ in noncommutative gauge field theories where neutrinos possess a tree-level coupling to photons in a generation-independent manner. In the energy range of interest (${10}^{10}$ to ${10}^{11}\text{ }\text{ }\mathrm{GeV}$), the $\ensuremath{\theta}$ expansion ($|\ensuremath{\theta}|\ensuremath{\sim}1/{\ensuremath{\Lambda}}_{\mathrm{NC}}^{2}$) and, therefore, the perturbative expansion, in terms of ${\ensuremath{\Lambda}}_{\mathrm{NC}}$, retains no longer its meaningful character, forcing us to resort to those NC field theoretical frameworks involving the full $\ensuremath{\theta}$ resummation. Our numerical analysis of the contribution to the process coming from the photon exchange impeccably pins down a lower bound on ${\ensuremath{\Lambda}}_{\mathrm{NC}}$ to be as high as 900 (450) TeV, depending on the estimates for the cosmogenic neutrino flux. If, on the other hand, one considers a surprising recent result that occurred in Pierre Auger Observatory data, that UHE cosmic rays are mainly composed of highly ionized Fe nuclei, then our bounds get weaker, due to the diminished cosmic neutrino flux. Nevertheless, we show that, even for the very high fraction of heavy nuclei in primary UHE cosmic rays, our method may still yield remarkable bounds on ${\ensuremath{\Lambda}}_{\mathrm{NC}}$, typically always above 200 TeV. Albeit, in this case, one encounters a maximal value for the Fe fraction, from which any useful information on ${\ensuremath{\Lambda}}_{\mathrm{NC}}$ can be drawn, delimiting thus the applicability of our method.

Characteristics of the copolymerized CR-39/DAP track detector for the observation of ultra heavy nuclei in galactic cosmic rays

A new copolymer of CR-39 and DAP resin was developed for the selective detection of ultra heavy nuclei in galactic cosmic rays. The track registration sensitivity for heavy ions with various Z ∗/ β was verified for copolymers mixing CR-39 (BARYOTRAK) with various concentrations of DAP using heavy ion beams at the HIMAC accelerator. In order to realize sufficient polymerization of CR-39/DAP copolymer, the optimum fabricating method was also verified by modifying the concentration of the initiator and temperature–time curing cycle for the copolymerization. CR-39 (BARYOTRAK) used for the base material of copolymerization has many advantages: 1) high uniformity of detector response, 2) extremely clear surface condition after etching, and 3) excellent charge and mass resolutions for heavy ions. The surface condition of the copolymer after etching is remarkably improved by using the BARYOTRAK monomer and its track registration sensitivity is controllable by changing the DAP concentration. However the detection threshold of the CR-39 (BARYOTRAK)/DAP copolymer is not yet satisfactory.

Control of the detection threshold of CR-39 PNTD for measuring ultra heavy nuclei in galactic cosmic rays

It is necessary to develop a track detector with higher detection threshold and high charge resolution for ultra heavy cosmic ray observation. The track registration sensitivity in CR-39 track detector etched by PEW (Potassium–Ethanol–Water) solution was verified using heavy ion beams at the HIMAC accelerator. It was found that PEW solution makes effectively to desensitize the track registration sensitivity in CR-39 detector. Its detection threshold of Z ∗/β is successfully raised to be Z ∗/β = 39 by using PEW solution with the concentration of ethanol of 45 wt%. However this produces a “fuzzy track”. A two-step process of etching involving a post-etch with 7 mol/ l sodium hydroxide solution produced very clear track edges and remarkably improves the charge resolution for heavy ions.

Atom & cosmos: Team finds abundant heavy nuclei in the highest‐energy cosmic rays: Iron's presence deepens puzzle about rare particles' origins

Science NewsVolume 176, Issue 2 p. 8-8 In The News Atom & cosmos: Team finds abundant heavy nuclei in the highest-energy cosmic rays: Iron's presence deepens puzzle about rare particles' origins Ron Cowen, Ron CowenSearch for more papers by this author Ron Cowen, Ron CowenSearch for more papers by this author First published: 09 October 2009 https://doi.org/10.1002/scin.5591760205AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume176, Issue218 July 2009Pages 8-8 RelatedInformation

A Program for the Precise Observations of Ultra Heavy Nuclei in Galactic Cosmic Rays

The origin of galactic cosmic rays (GCRs) nuclei is still unknown. Precise observation of ultra heavy GCRs would be an important step in resolving their origin including the remaining problems in cosmic ray astrophysics. A program to observe UH nuclei in GCRs is proposed which involves the use of a high performance solid-state track detector on board a long-duration balloon. The program focuses measuring the elemental and isotopic compositions of UH nuclei up to the actinides. The observation of nuclear composition covers a wide range of scientific themes including studies of nucleosynthesis in cosmic ray sources, chemical evolution of galactic material, the characteristic time of cosmic rays, and heating and acceleration mechanisms of cosmic ray particles.

High Speed Microscope for Large Scale Ultra Heavy Nuclei Search using Solid State Track Detector

A large scale observation program of ultra heavy nuclei ( Z ≥30) in galactic cosmic rays (UH-GCRs) is planned with the use of solid-state track detectors (SSTD) such as CR-39 plastic and BP-1 glass on the International Space Station and on board long-duration balloon flights. The handling of SSTDs usually requires a large number of year × person to scan and analyze the etch pits produced on the detector. It is due to the manual or semi-automatic analysis using a conventional optical microscope system. We plan to use a cosmic ray telescope with a large exposure area of 20 m 2 made of the SSTD stacks. Detector handling will be more difficult as compared with before. A major problem for such a large scale experiment is how to quickly and precisely analyze the etch pit obtained over a short period. We have developed a new microscope system, the HSP-1000, for high speed image acquisition that uses a line sensor camera in place of a traditional CCD camera. Continuous, automatic focusing of the microscope is ach...

Measurements of cosmic-ray secondary nuclei at high energies with the first flight of the CREAM balloon-borne experiment

We present new measurements of heavy cosmic-ray nuclei at high energies performed during the first flight of the balloon-borne cosmic-ray experiment Cosmic-Ray Energetics and Mass (CREAM). This instrument uses multiple charge detectors and a transition radiation detector to provide the first high accuracy measurements of the relative abundances of elements from boron to oxygen up to energies around 1 TeV/n. The data agree with previous measurements at lower energies and show a relatively steep decline (∼ E −0.6 to E −0.5) at high energies. They further show the source abundance of nitrogen relative to oxygen is ∼10% in the TeV/n region.

Cosmic Ray Transport and Production in the Galaxy: A Stochastic Propagation Simulation Approach

Galactic cosmic-ray composition reflects the effects of nuclear interactions during propagation through the interstellar medium. In order to use measurements to determine the source of cosmic rays, one needs a model to deconvolute the propagation effect. This paper presents a new numerical method to solve cosmic-ray diffusive transport equations with a complete network of nuclear interactions. The new method uses the time backward Markov stochastic processes to solve the transport equation by tracing the particles' trajectories starting from the solar system back to their sources in the Galaxy. To make the calculation efficient for large arrays of equations for many cosmic-ray species, a matrix representing the composition of all cosmic-ray heavy nuclei and location is used. The results for abundance ratios of key elements such as B/C and sub-Fe/Fe compared with observations from HEAO-3, ACE, and Ulysses and for isotopic ratios such as 36Cl/37Cl and 54Mn/55Mn are shown to be consistent with other numerical approaches. The ability to track particles through the Galaxy, which is inherent in this technique, offers new opportunities for investigations. For example, one can look at the spatial and propagation time distributions and element composition of source particles that arrive in the solar system.

On the Origin and Survival of Ultra‐High‐Energy Cosmic‐Ray Nuclei in Gamma‐Ray Bursts and Hypernovae

The chemical composition of the ultra-high-energy (UHE) cosmic rays serves as an important clue for their origin. Recent measurements of the elongation rates by the Pierre Auger Observatory hint at the possible presence of heavy or intermediate mass nuclei in the UHE cosmic rays. Gamma-ray bursts (GRBs) and hypernovae have been suggested as possible sources of the UHE cosmic rays. Here we derive the constraints on the physical conditions under which UHE heavy nuclei, if they are accelerated in these sources, can survive in their intense photon fields. We find that in the GRB external shock and in the hypernova scenarios, UHE nuclei can easily survive photo-disintegration. In the GRB internal shock scenario, UHE nuclei can also survive, provided the dissipation radius and/or the bulk Lorentz factor of the relativistic outflow are relatively large, or if the low-energy self-absorption break in the photon spectrum of the prompt emission occurs above several KeV. In internal shocks and in the other scenarios, intermediate-mass UHE nuclei have a higher probability of survival against photo-disintegration than UHE heavy nuclei such as Fe.

Geometrical track parameters in the pallasite olivine: Identification of the cosmic ray heavy nuclei

The geometry characteristics of chemically etched tracks in the not annealed olivine crystals from pallasite meteorites are investigated with the search and identification goal of fossil tracks of galactic cosmic ray heavy and superheavy nuclei. The chosen methodology is based on precise measurements of the nucleus track parameters in the course of chemical etching of the olivine crystals. Geometric parameters of individual tracks are traced and measured in course of their step-by-step chemical etching by using a modern high-precision, completely automated facility PAVICOM designed at the Lebedev Physical Institute of Russian Academy of Sciences. A method of the layer-by-layer removal of olivine material is employed, which allows the tracks to be studied over the whole crystal volume under study. It is planned to measure the next main parameters: the cone length and diameters of etched track within the initial, high-energy section of its formation; the total residual range and diameters, corresponding to saturation zone of the primary ionization; and the etching rate along the different parts of tracks, the starting inter-volume olivine crystal point for which were fixed. The preliminary experimental results obtained for 42 tracks, detected and analyzed in the Marjalahti pallasite olivine crystals, are presented.