David Droz

University of Geneva

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A. Tykhonov

University of Geneva

M. N. Mazziotta

Istituto Nazionale di Fisica Nucleare, Sezione di Bari

P. Fusco

Istituto Nazionale di Fisica Nucleare, Sezione di Bari

G. Marsella

University of Palermo

I. De Mitri

Istituto Nazionale di Fisica Nucleare

F. Gargano

Istituto Nazionale di Fisica Nucleare, Sezione di Bari

Giacinto Donvito

University of Science and Technology of China

Rui Qiao

Chinese Academy of Sciences

Chuan Yue

Liaoning Normal University

Ke Gong

Chinese Academy of Sciences

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Chinese Academy of Sciences

498

University of Science and Technology of China

338

Purple Mountain Observatory

262

University of Chinese Academy of Sciences

171

Institute of High Energy Physics

128

Campbell Collaboration

Institute of Modern Physics

Istituto Nazionale di Fisica Nucleare

University of Geneva

National Space Science Center

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Latest results on searching for fractionally charged particles with the DAMPE experiment

Proceedings of 36th International Cosmic Ray Conference — PoS(ICRC2019) (2023)

Chengming Liu Francesca Alemanno Corrado Altomare Qi An P. Azzarello

The existence of fractionally charged particles (FCP) is foreseen in extensions of or beyond the Standard Model of particle physics. Most of the previously conducted searches for FCPs in cosmic rays were based on experiments underground or at high altitudes. However, there have been few searches for FCPs in cosmic rays carried out in orbit other than AMS-01 flown by a space shuttle and BESS by a balloon at the top of the atmosphere. In this study, we conduct an FCP search in space based on on-orbit data obtained using the Dark Matter Particle Explorer (DAMPE) satellite over a period of five years. Unlike underground experiments, which require an FCP energy of the order of hundreds of GeV, our FCP search starts at only a few GeV. An upper limit of $6.2\times 10^{-10}~~\mathrm{cm^{-2}sr^{-1} s^{-1}}$ is obtained for the flux. Our results demonstrate that DAMPE exhibits higher sensitivity than experiments of similar types by three orders of magnitude that more stringently restricts the conditions for the existence of FCP in primary cosmic rays.

Orbit (dynamics)

Particle (ecology)

International Space Station

10.22323/1.444.0149

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Citations (1)

Hadronic cross section measurements with the DAMPE space mission using 20GeV-10TeV cosmic-ray protons and $^4$He

arXiv (Cornell University) (2024)

F. Alemanno Q. An P. Azzarello F. C. T. Barbato P. Bernardini

Precise direct cosmic-ray (CR) measurements provide an important probe to study the energetic particle sources in our Galaxy, and the interstellar environment through which these particles propagate. Uncertainties on hadronic models, ion-nucleon cross sections in particular, are currently the limiting factor towards obtaining more accurate CR ion flux measurements with calorimetric space-based experiments. We present an energy-dependent measurement of the inelastic cross section of protons and helium-4 nuclei (alpha particles) on a Bi$_4$Ge$_3$O$_{12}$ target, using 88 months of data collected by the DAMPE space mission. The kinetic energy range per nucleon of the measurement points ranges from 18 GeV to 9 TeV for protons, and from 5 GeV/n to 3 TeV/n for helium-4 nuclei. Our results lead to a significant improvement of the CR flux normalisation. In the case of helium-4, these results correspond to the first cross section measurements on a heavy target material at energies above 10 GeV/n.

Section (typography)

10.48550/arxiv.2408.17224

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On-orbit performance of the DAMPE BGO calorimeter

Proceedings of 36th International Cosmic Ray Conference — PoS(ICRC2019) (2021)

Yifeng Wei Felicia Barbato Elisabetta Casilli F. de Palma G. Marsella

The DArk Matter Particle Explorer (DAMPE) is the first Chinese cosmic-ray direct detection experiment. It has been operating smoothly on-orbit since its successful launch at the end of 2015. Currently, its sub-detectors and the satellite are in good working order. The DAMPE payload employs a BGO Calorimeter for energy measurements, trigger and e/p identification. The calorimeter is constructed of 308 BGO crystals, and PMTs are coupled to the crystals with optical filters to readout scintillation light. In this work, we present the status and performance of the calorimeter, including status of detector units, energy measurement, especially in TeV range, detector endurance, and long term performance in a duration of 65 months.

Calorimeter (particle physics)

Payload (computing)

Orbit (dynamics)

10.22323/1.395.0081

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Measurements of the boron-to-carbon and boron-to-oxygen flux ratios in cosmic rays with DAMPE

Proceedings of 36th International Cosmic Ray Conference — PoS(ICRC2019) (2023)

Chuan Yue Zhan Fang Chen Dimitrios Kyratzis A. Parenti Yi Feng Wei

Boron nuclei in cosmic rays (CRs) are believed to be mainly produced by the fragmentation of heavier nuclei, such as carbon and oxygen, via collisions with the interstellar matter. Therefore, the boron-to-carbon flux ratio (B/C) and the boron-to-oxygen flux ratio (B/O) are very essential probes of the CR propagation. With a large geometric factor and a good charge resolution, the DArk Matter Particle Explorer (DAMPE), is expected to extend the measurement of B/C and B/O up to a few TeV/n energies. In this contribution, the direct measurements of B/C and B/O in the energy range from 10 GeV/n to 5.6 TeV/n with six years of data collected by DAMPE are presented.

Carbon fibers

Isotopes of boron

Fragmentation

10.22323/1.444.0159

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Measurement of the Cosmic Ray Helium Energy Spectrum from 70 GeV to 80 TeV with the DAMPE Space Mission

Physical Review Letters (2021)

Francesco Alemanno Q. An P. Azzarello Felicia Barbato P. Bernardini

The measurement of the energy spectrum of cosmic ray helium nuclei from 70 GeV to 80 TeV using 4.5 years of data recorded by the Dark Matter Particle Explorer (DAMPE) is reported in this work. A hardening of the spectrum is observed at an energy of about 1.3 TeV, similar to previous observations. In addition, a spectral softening at about 34 TeV is revealed for the first time with large statistics and well controlled systematic uncertainties, with an overall significance of 4.3σ. The DAMPE spectral measurements of both cosmic protons and helium nuclei suggest a particle charge dependent softening energy, although with current uncertainties a dependence on the number of nucleons cannot be ruled out.Received 5 January 2021Revised 25 March 2021Accepted 6 April 2021DOI:https://doi.org/10.1103/PhysRevLett.126.201102© 2021 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasCosmic ray & astroparticle detectorsCosmic ray composition & spectraParticle astrophysicsGravitation, Cosmology & Astrophysics

Energy spectrum

10.1103/physrevlett.126.201102

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A PCA-based Method for Electron-Proton Discrimination of the DAMPE Experiment

Proceedings of 36th International Cosmic Ray Conference — PoS(ICRC2019) (2023)

Ming-Yang Cui Francesca Alemanno Corrado Altomare Qi An P. Azzarello

Galactic cosmic rays are mostly made up of energetic nuclei, with less than 1% of electrons (and positrons). Precise measurement of the electron and positron component requires a very efficient method to reject the nuclei background, mainly protons. In this work, we develop an unsupervised machine learning method to identify electrons and positrons from cosmic ray protons for the Dark Matter Particle Explorer (DAMPE) experiment. Compared with the supervised learning method used in the DAMPE experiment, this unsupervised method relies solely on real data except for the background estimation process. As a result, it could effectively reduce the uncertainties from simulations. For three energy ranges of electrons and positrons, 80–128 GeV, 350–700 GeV and 2–5 TeV, the residual background fractions in the electron sample are found to be about (0.45 ± 0.02)%, (0.52 ± 0.04)% and (10.55 ± 1.80)%, and the background rejection power is about (6.21 ± 0.03) × 104, (9.03 ± 0.05) × 104 and (3.06 ± 0.32) × 104, respectively. This method gives a higher background rejection power in all energy ranges than the traditional morphological parameterization method and reaches comparable background rejection performance compared with supervised machine learning methods.

Annihilation

10.22323/1.444.0131

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The PCA Lens-Finder: application to CFHTLS

Astronomy and Astrophysics (2016)

D. Paraficz F. Courbin A. Tramacere R. Joseph R. B. Metcalf

We present the results of a new search for galaxy-scale strong lensing systems in CFHTLS Wide. Our lens-finding technique involves a preselection of potential lens galaxies, applying simple cuts in size and magnitude. We then perform a Principal Component Analysis of the galaxy images, ensuring a clean removal of the light profile. Lensed features are searched for in the residual images using the clustering topometric algorithm DBSCAN. We find 1098 lens candidates that we inspect visually, leading to a cleaned sample of 109 new lens candidates. Using realistic image simulations we estimate the completeness of our sample and show that it is independent of source surface brightness, Einstein ring size (image separation) or lens redshift. We compare the properties of our sample to previous lens searches in CFHTLS. Including the present search, the total number of lenses found in CFHTLS amounts to 678, which corresponds to ~4 lenses per square degree down to i=24.8. This is equivalent to ~ 60.000 lenses in total in a survey as wide as Euclid, but at the CFHTLS resolution and depth.

Sample (material)

10.1051/0004-6361/201527971

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Citations (36)

Observations of gamma-ray sources with DAMPE

Proceedings of 36th International Cosmic Ray Conference — PoS(ICRC2019) (2021)

Kai-Kai Duan Wei Jiang Xiang Li Zhao Qiang Shen Zun Lei Xu

DArk Matter Particle Explorer (DAMPE), a space-borne high energy cosmic ray and gamma-ray detector, has surveyed the whole sky for five years and collected more than 220,000 photons above 2 GeV since the launching on Dec. 17, 2015. The instrument response functions (IRFs) are derived and a dedicated software named DmpST is developed for the gamma-ray data analysis of DAMPE. Here we present the method of DAMPE bright gamma-ray sources search and the spectral analyses of these sources.

10.22323/1.395.0631

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Observations of Forbush Decreases of Cosmic-Ray Electrons and Positrons with the Dark Matter Particle Explorer

The Astrophysical Journal Letters (2021)

Francesca Alemanno Qi An P. Azzarello Felicia Barbato P. Bernardini

Abstract The Forbush decrease (FD) represents the rapid decrease of the intensities of charged particles accompanied with the coronal mass ejections or high-speed streams from coronal holes. It has been mainly explored with the ground-based neutron monitor network, which indirectly measures the integrated intensities of all species of cosmic rays by counting secondary neutrons produced from interaction between atmospheric atoms and cosmic rays. The space-based experiments can resolve the species of particles but the energy ranges are limited by the relatively small acceptances except for the most abundant particles like protons and helium. Therefore, the FD of cosmic-ray electrons and positrons have just been investigated by the PAMELA experiment in the low-energy range (<5 GeV) with limited statistics. In this paper, we study the FD event that occurred in 2017 September with the electron and positron data recorded by the Dark Matter Particle Explorer. The evolution of the FDs from 2 GeV to 20 GeV with a time resolution of 6 hr are given. We observe two solar energetic particle events in the time profile of the intensity of cosmic rays, the earlier, and weaker, one has not been shown in the neutron monitor data. Furthermore, both the amplitude and recovery time of fluxes of electrons and positrons show clear energy dependence, which is important in probing the disturbances of the interplanetary environment by the coronal mass ejections.

PAMELA detector

Particle (ecology)

Forbush decrease

10.3847/2041-8213/ac2de6

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Citations (15)

Point-like Source Catalog Observed by DAMPE

Proceedings of 36th International Cosmic Ray Conference — PoS(ICRC2019) (2023)

Kai-Kai Duan Francesca Alemanno Corrado Altomare Qi An P. Azzarello

The DArk Matter Particle Explorer (DAMPE) is a high-energy cosmic ray and gamma-ray detector located in space. Over a period of seven years since its launch on December 17, 2015, DAMPE has surveyed the entire sky and collected an extensive dataset of more than 300,000 photons with energies above 2 GeV. To analyze the gamma-ray data obtained by DAMPE, instrument response functions (IRFs) have been derived, and a specialized software called DmpST has been developed. In this context, we present the results of the DAMPE gamma-ray point-like source catalog. This catalog provides valuable information about the detected gamma-ray sources, which includes details such as the positions, energy spectra, and flux measurements of these point-like gamma-ray sources. By studying these sources, scientists can gain insights into various astrophysical phenomena, including the emission processes and distribution of gamma-ray sources in the universe.

10.22323/1.444.0669

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Citations (3)