Author: "Loparco F" - Searchworks@Jio Institute Digital Library Search Results

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1,119 results on '"Loparco F"'

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

Author: Alemanno, F., An, Q., Azzarello, P., Barbato, F. C. T., Bernardini, P., Bi, X. J., Cagnoli, I., Cai, M. S., Casilli, E., Catanzani, E., Chang, J., Chen, D. Y., Chen, J. L., Chen, Z. F., Coppin, P., Cui, M. Y., Cui, T. S., Cui, Y. X., Dai, H. T., De Benedittis, A., De Mitri, I., de Palma, F., Di Giovanni, A., Ding, Q., Dong, T. K., Dong, Z. X., Donvito, G., Droz, D., Duan, J. L., Duan, K. K., Fan, R. R., Fan, Y. Z., Fang, F., Fang, K., Feng, C. Q., Feng, L., Frieden, J. M., Fusco, P., Gao, M., Gargano, F., Gong, K., Gong, Y. Z., Guo, D. Y., Guo, J. H., Han, S. X., Hu, Y. M., Huang, G. S., Huang, X. Y., Huang, Y. Y., Ionica, M., Jiang, L. Y., Jiang, Y. Z., Jiang, W., Kong, J., Kotenko, A., Kyratzis, D., Lei, S. J., Li, W. H., Li, W. L., Li, X., Li, X. Q., Liang, Y. M., Liu, C. M., Liu, H., Liu, J., Liu, S. B., Liu, Y., Loparco, F., Luo, C. N., Ma, M., Ma, P. X., Ma, T., Ma, X. Y., Marsella, G., Mazziotta, M. N., Mo, D., Niu, X. Y., Pan, X., Parenti, A., Peng, W. X., Peng, X. Y., Perrina, C., Putti-Garcia, E., Qiao, R., Rao, J. N., Ruina, A., Sarkar, R., Savina, P., Serpolla, A., Shangguan, Z., Shen, W. H., Shen, Z. Q., Shen, Z. T., Silveri, L., Song, J. X., Stolpovskiy, M., Su, H., Su, M., Sun, H. R., Sun, Z. Y., Surdo, A., Teng, X. J., Tykhonov, A., Wang, J. Z., Wang, L. G., Wang, S., Wang, S. X., Wang, X. L., Wang, Y., Wang, Y. F., Wang, Y. Z., Wang, Z. M., Wei, D. M., Wei, J. J., Wei, Y. F., Wu, D., Wu, J., Wu, S. S., Wu, X., Xia, Z. Q., Xu, H. T., Xu, J., Xu, Z. H., Xu, Z. L., Xu, E. H., Xu, Z. Z., Xue, G. F., Yang, H. B., Yang, P., Yang, Y. Q., Yao, H. J., Yu, Y. H., Yuan, G. W., Yuan, Q., Yue, C., Zang, J. J., Zhang, S. X., Zhang, W. Z., Zhang, Yan, Zhang, Yi, Zhang, Y. J., Zhang, Y. L., Zhang, Y. P., Zhang, Y. Q., Zhang, Z., Zhang, Z. Y., Zhao, C., Zhao, H. Y., Zhao, X. F., Zhou, C. Y., and Zhu, Y.
Subjects: High Energy Physics - Experiment
Abstract: 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., Comment: 17 pages, submitted to PRD
Published: 2024

2. The High Efficiency fast-Response GAmma (HERGA) detector based on SiPM readout

Author: Altomare C., Cerasole D., Di Venere L., Fanchini E., Gargano F., Giordano F., Loparco F., Loporchio S., Mastroserio A., Morichi M., Pantaleo F.R., Serini D., Spinelli P., and Swiderski L.
Subjects: gamma rays, environmental monitoring, norm, scintillator crystals, silicon photomultipliers, Physics, QC1-999
Abstract: Gamma-ray spectroscopy and gamma-ray imaging are two complementary techniques used for the localization and the identification of radioactive sources containing gamma-ray emitting radioisotopes. The radioactivity monitoring is focused on the detection of both artificial and environmental radioactive sources like Naturally Occurring Radioactive Materials (NORM). This kind of contamination becomes dangerous when the detection of the unwanted substances exhibits a concentration significantly above the environmental radioactive background radiation levels. For this purpose, we have developed, tested and shown a High Efficiency fast-Response GAmma (HERGA) detector useful for the identification of radionuclides and for gamma-ray imaging. A first version of the gamma detector prototype was composed of 16 CsI(Tl) scintillating crystals of 3x3x10 cm3 size, arranged in 4x4 matrix coupled with standard Photomultiplier tubes (PMTs). An image reconstruction of a radioactive gamma emitter source is possible using the coded mask technique, in which a 7x7 mask, made of Plastic and Tungsten tiles, is placed in front of the detector and a pattern recognition algorithm based on classical statistical methods (Kolmogorov Smirnov) is used to reconstruct the source position. The measurements carried out showed a point spread function (PSF) of a few mrad for pointlike sources. The Minimum Detectable Activity (MDA) was also determined in the case of pointlike radioactive sources. In this contribution we will present an update of the HERGA detector prototype in which Silicon Photomultipliers (SiPMs) are used in place of the PMTs. SiPMs provide similar or even better performance compared to the standard PMT sand provide benefits in terms of lower power consumption and reduced cost and compactness. The advantages of the SiPM technology are also characterized by the robustness of the photosensor that makes the new prototype compact, portable, ideal for in-situ and real-time. We will show a comparison between the results obtained with the newest SiPM read-out technology with respect to those obtained with the PMT one, in terms of energy and spatial resolution. The imaging performance is also in phase of testing in order to localize extended radioactive sources such as for example NORM samples or to detect inaccessible or hidden nuclear waste.
Published: 2023
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3. On the decay mode $\Lambda_b \to X_s \gamma$

Author: Colangelo, P., De Fazio, F., and Loparco, F.
Subjects: High Energy Physics - Phenomenology, High Energy Physics - Experiment, High Energy Physics - Lattice
Abstract: We study the inclusive $H_b \to X_s \gamma$ decay with $H_b$ a beauty baryon, in particular $\Lambda_b$, employing an expansion in the heavy quark mass at $\mathit{O}(m_b^{-3})$ at leading order in $\alpha_s$, keeping the dependence on the hadron spin. For a polarized baryon we compute the distribution $\displaystyle\frac{d^2\Gamma}{dy \, d \cos \theta_P}$, with $y=2E_\gamma/m_b$, $E_\gamma$ the photon energy and $\theta_P$ the angle between the baryon spin vector and the photon momentum in the $H_b$ rest-frame. We discuss the correlation between the baryon and photon polarization, and show that effects of physics beyond the Standard Model can modify the photon polarization asymmetry. We also discuss a method to treat the singular terms in the photon energy spectrum obtained by the OPE., Comment: Latex 23 pages, 3 figures. Matches the published version
Published: 2023

4. Constraints on the gamma-ray emission from Small Solar System Bodies with the Fermi Large Area Telescope data

Author: De Gaetano, S., Di Venere, L., Gargano, F., Loparco, F., Lorusso, L., Mazziotta, M. N., Panzarini, G., Pillera, R., and Serini, D.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Solar and Stellar Astrophysics
Abstract: All known Small Solar System Bodies have diameters between a few meters and a few thousands of kilometers. Based on the collisional evolution of Solar System Bodies, a larger number of asteroids with diameters down to $\sim 2$ m is thought to exist. As all Solar System Bodies, Small Bodies can be passive sources of high-energy gamma rays, produced by the interaction of energetic cosmic rays impinging on their surfaces. Since the majority of known asteroids are in orbits between Mars and Jupiter (in a region known as the Main Belt), we expect them to produce a diffuse emission close to the ecliptic plane. In this work we have studied the gamma-ray emission coming from the ecliptic using the data collected by the Large Area Telescope onboard the Fermi satellite. We have fit the results with simulations of the gamma-ray intensity at source level (calculated with the software FLUKA) to constrain the Small Solar System Bodies population. Finally, we have proposed a model describing the distribution of asteroid sizes and we have used the LAT data to constrain the gamma-ray emission expected from this model and, in turn, on the model itself., Comment: 21 pages, 18 figures; accepted for publication in ApJ
Published: 2023
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5. Measurement of the cosmic p+He energy spectrum from 50 GeV to 0.5 PeV with the DAMPE space mission

Author: DAMPE Collaboration, Alemanno, F., Altomare, C., An, Q., Azzarello, P., Barbato, F. C. T., Bernardini, P., Bi, X. J., Cagnoli, I., Cai, M. S., Casilli, E., Catanzani, E., Chang, J., Chen, D. Y., Chen, J. L., Chen, Z. F., Coppin, P., Cui, M. Y., Cui, T. S., Cui, Y. X., Dai, H. T., De Benedittis, A., De Mitri, I., de Palma, F., Deliyergiyev, M., Di Giovanni, A., Di Santo, M., Ding, Q., Dong, T. K., Dong, Z. X., Donvito, G., Droz, D., Duan, J. L., Duan, K. K., Fan, R. R., Fan, Y. Z., Fang, F., Fang, K., Feng, C. Q., Feng, L., Alonso, M. Fernandez, Frieden, J. M., Fusco, P., Gao, M., Gargano, F., Gong, K., Gong, Y. Z., Guo, D. Y., Guo, J. H., Han, S. X., Hu, Y. M., Huang, G. S., Huang, X. Y., Huang, Y. Y., Ionica, M., Jiang, L. Y., Jiang, Y. Z., Jiang, W., Kong, J., Kotenko, A., Kyratzis, D., Lei, S. J., Li, W. H., Li, W. L., Li, X., Li, X. Q., Liang, Y. M., Liu, C. M., Liu, H., Liu, J., Liu, S. B., Liu, Y., Loparco, F., Luo, C. N., Ma, M., Ma, P. X., Ma, T., Ma, X. Y., Marsella, G., Mazziotta, M. N., Mo, D., Salinas, M. Muñoz, Niu, X. Y., Pan, X., Parenti, A., Peng, W. X., Peng, X. Y., Perrina, C., Putti-Garcia, E., Qiao, R., Rao, J. N., Ruina, A., Shangguan, Z., Shen, W. H., Shen, Z. Q., Shen, Z. T., Silveri, L., Song, J. X., Stolpovskiy, M., Su, H., Su, M., Sun, H. R., Sun, Z. Y., Surdo, A., Teng, X. J., Tykhonov, A., Wang, J. Z., Wang, L. G., Wang, S., Wang, S. X., Wang, X. L., Wang, Y., Wang, Y. F., Wang, Y. Z., Wang, Z. M., Wei, D. M., Wei, J. J., Wei, Y. F., Wu, D., Wu, J., Wu, L. B., Wu, S. S., Wu, X., Xia, Z. Q., Xu, H. T., Xu, J., Xu, Z. H., Xu, Z. L., Xu, E. H., Xu, Z. Z., Xue, G. F., Yang, H. B., Yang, P., Yang, Y. Q., Yao, H. J., Yu, Y. H., Yuan, G. W., Yuan, Q., Yue, C., Zang, J. J., Zhang, S. X., Zhang, W. Z., Zhang, Yan, Zhang, Yi, Zhang, Y. J., Zhang, Y. L., Zhang, Y. P., Zhang, Y. Q., Zhang, Z., Zhang, Z. Y., Zhao, C., Zhao, H. Y., Zhao, X. F., Zhou, C. Y., and Zhu, Y.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment
Abstract: Recent observations of the light component of the cosmic-ray spectrum have revealed unexpected features that motivate further and more precise measurements up to the highest energies. The Dark Matter Particle Explorer is a satellite-based cosmic-ray experiment that has been operational since December 2015, continuously collecting data on high-energy cosmic particles with very good statistics, energy resolution, and particle identification capabilities. In this work, the latest measurements of the energy spectrum of proton+helium in the energy range from 46 GeV to 464 TeV are presented. Among the most distinctive features of the spectrum, a spectral hardening at 600 GeV has been observed, along with a softening at 29 TeV measured with a 6.6{\sigma} significance. Moreover, the detector features and the analysis approach allowed for the extension of the spectral measurement up to the sub-PeV region. Even if with small statistical significance due to the low number of events, data suggest a new spectral hardening at about 150 TeV., Comment: Published on PRD
Published: 2023
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6. Fermi-GBM Discovery of GRB 221009A: An Extraordinarily Bright GRB from Onset to Afterglow

Author: Lesage, S., Veres, P., Briggs, M. S., Goldstein, A., Kocevski, D., Burns, E., Wilson-Hodge, C. A., Bhat, P. N., Huppenkothen, D., Fryer, C. L., Hamburg, R., Racusin, J., Bissaldi, E., Cleveland, W. H., Dalessi, S., Fletcher, C., Giles, M. M., Hristov, B. A., Hui, C. M., Mailyan, B., Malacaria, C., Poolakkil, S., Roberts, O. J., von Kienlin, A., Wood, J., Ajello, M., Arimoto, M., Baldini, L., Ballet, J., Baring, M. G., Bastieri, D., Gonzalez, J. Becerra, Bellazzini, R., Blandford, R. D., Bonino, R., Bruel, P., Buson, S., Cameron, R. A., Caputo, R., Caraveo, P. A., Cavazzuti, E., Chiaro, G., Cibrario, N., Ciprini, S., Orestano, P. Cristarella, Crnogorcevic, M., Cuoco, A., Cutini, S., DAmmando, F., De Gaetano, S., Di Lalla, N., Di Venere, L., Dominguez, A., Fegan, S. J., Ferrara, E. C., Fleischhack, H., Fukazawa, Y., Funk, S., Fusco, P., Galanti, G., Gammaldi, V., Gargano, F., Gasbarra, C., Gasparrini, D., Germani, S., Giacchino, F., Giglietto, N., Gill, R., Giroletti, M., Granot, J., Green, D., Grenier, I. A., Guiriec, S., Gustafsson, M., Hays, E., Hewitt, J. W., Horan, D., Hou, X., Kuss, M., Latronico, L., Laviron, A., Lemoine-Goumard, M., Li, J., Liodakis, I., Longo, F., Loparco, F., Lorusso, L., Lovellette, M. N., Lubrano, P., Maldera, S., Manfreda, A., Marti-Devesa, G., Mazziotta, M. N., McEnery, J. E., Mereu, I., Meyer, M., Michelson, P. F., Mizuno, T., Monzani, M. E., Morselli, A., Moskalenko, I. V., Negro, M., Nuss, E., Omodei, N., Orlando, E., Ormes, J. F., Paneque, D., Panzarini, G., Persic, M., Pesce-Rollins, M., Pillera, R., Piron, F., Poon, H., Porter, T. A., Principe, G., Raino, S., Rando, R., Rani, B., Razzano, M., Razzaque, S., Reimer, A., Reimer, O., Ryde, F., Sanchez-Conde, M., Parkinson, P. M. Saz, Scotton, L., Serini, D., Sgro, C., Sharma, V., Siskind, E. J., Spandre, G., Spinelli, P., Tajima, H., Torres, D. F., Valverde, J., Venters, T., Wadiasingh, Z., Wood, K., and Zaharijas, G.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We report the discovery of GRB 221009A, the highest flux gamma-ray burst ever observed by the Fermi Gamma-ray Burst Monitor (GBM). This GRB has continuous prompt emission lasting more than 600 seconds which smoothly transitions to afterglow visible in the GBM energy range (8 keV--40 MeV), and total energetics higher than any other burst in the GBM sample. By using a variety of new and existing analysis techniques we probe the spectral and temporal evolution of GRB 221009A. We find no emission prior to the GBM trigger time (t0; 2022 October 9 at 13:16:59.99 UTC), indicating that this is the time of prompt emission onset. The triggering pulse exhibits distinct spectral and temporal properties suggestive of the thermal, photospheric emission of shock-breakout, with significant emission up to $\sim$15 MeV. We characterize the onset of external shock at t0+600 s and find evidence of a plateau region in the early-afterglow phase which transitions to a slope consistent with Swift-XRT afterglow measurements. We place the total energetics of GRB 221009A in context with the rest of the GBM sample and find that this GRB has the highest total isotropic-equivalent energy ($\textrm{E}_{\gamma,\textrm{iso}}=1.0\times10^{55}$ erg) and second highest isotropic-equivalent luminosity ($\textrm{L}_{\gamma,\textrm{iso}}=9.9\times10^{53}$ erg/s) based on redshift of z = 0.151. These extreme energetics are what allowed us to observe the continuously emitting central engine of GBM from the beginning of the prompt emission phase through the onset of early afterglow., Comment: 26 pages 7 figures - accepted for publication in ApJL
Published: 2023
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7. The EXTRA-BL4S experiment for the measurement of the energy and angular distributions of transition radiation X-rays

Author: Mazziotta, M. N., Loparco, F., Anelli, A., Belviso, M. M., Buquicchio, A., Cassano, E. V., De Cosmo, M., Ginefra, P., Martulli, M. L., Picci, C., Picicci, D., Soriano, R. D., Tatulli, A. P., Tripaldella, G., Zupo, V. M., Muscarella, M. F., Turbacci, S., Boselli, M., Silva, C. B. da Cruz E, Joos, M., and Schütze, P.
Subjects: High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract: We have designed and implemented an experiment to measure the angular distributions and the energy spectra of the transition radiation X-rays emitted by fast electrons and positrons crossing different radiators. Our experiment was selected among the proposals of the 2021 Beamline for Schools contest, a competition for high-school students organized every year by CERN and DESY, and was performed at the DESY II Test Beam facility area TB21, using a high-purity beam of electrons or positrons with momenta in the range from 1 to 6 GeV/c. The measurements were performed using a 100 um thick silicon pixel detector, with a pitch of 55 um. Our results are consistent with the expectations from the theoretical models describing the production of transition radiation in multilayer regular radiators., Comment: 18 pages, 11 figures; Version to match the accepted manuscript by JINST
Published: 2023
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8. The Fermi-LAT Light Curve Repository

Author: Abdollahi, S., Ajello, M., Baldini, L., Ballet, J., Bastieri, D., Gonzalez, J. Becerra, Bellazzini, R., Berretta, A., Bissaldi, E., Bonino, R., Brill, A., Bruel, P., Burns, E., Buson, S., Cameron, A., Caputo, R., Caraveo, P. A., Cibrario, N., Ciprini, S., Orestano, P. Cristarella, Crnogorcevic, M., Cutini, S., D'Ammando, F., De Gaetano, S., Digel, S. W., Di Lalla, N., Di Venere, L., Domínguez, A., Ramazani, V. Fallah, Fegan, S. J., Ferrara, E. C., Fiori, A., Fleischhack, H., Franckowiak, A., Fukazawa, Y., Fusco, P., Gammaldi, V., Gargano, F., Garrappa, S., Gasbarra, C., Gasparrini, D., Giglietto, N., Giordano, F., Giroletti, M., Green, D., Grenier, I. A., Guiriec, S., Gustafsson, M., Hays, E., Horan, D., Hou, X., Jóhannesson, G., Kerr, M., Kocevski, D., Kuss, M., Latronico, L., Li, J., Liodakis, I., Longo, F., Loparco, F., Lorusso, L., Lott, B., Lovellette, M. N., Lubrano, P., Maldera, S., Manfreda, A., Mart\'-Devesa, G., Mazziotta, M. N., Mereu, I., Meyer, M., Michelson, P. F., Mizuno, T., Monzani, M. E., Morselli, A., Moskalenko, I. V., Negro, M., Omodei, N., Orlando, E., Ormes, J. F., Paneque, D., Panzarini, G., Perkins, J. S., Persic, M., Pesce-Rollins, M., Pillera, R., Porter, T. A., Principe, G., Racusin, J. L., Rainò, S., Rando, R., Rani, B., Razzano, M., Razzaque, S., Reimer, A., Reimer, O., Sánchez-Conde, M., Parkinson, P. M. Saz, Scargle, Jeff, Scotton, L., Serini, D., Sgrò, C., Siskind, E. J., Spandre, G., Spinelli, P., Suson, D. J., Tajima, H., Thompson, D. J., Torres, D. F., Valverde, J., Venters, T., Wadiasingh, Z., Wagner, S., and Wood, K.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The Fermi Large Area Telescope (LAT) light curve repository (LCR) is a publicly available, continually updated library of gamma-ray light curves of variable Fermi-LAT sources generated over multiple timescales. The Fermi-LAT LCR aims to provide publication-quality light curves binned on timescales of 3 days, 7 days, and 30 days for 1525 sources deemed variable in the source catalog of the first 10 years of Fermi-LAT observations. The repository consists of light curves generated through full likelihood analyses that model the sources and the surrounding region, providing fluxes and photon indices for each time bin. The LCR is intended as a resource for the time-domain and multi-messenger communities by allowing users to quickly search LAT data to identify correlated variability and flaring emission episodes from gamma-ray sources. We describe the sample selection and analysis employed by the LCR and provide an overview of the associated data access portal., Comment: Accepted for publication in ApJ Supplement Series
Published: 2023
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9. Search for relativistic fractionally charged particles in space

Author: DAMPE Collaboration, Alemanno, F., Altomare, C., An, Q., Azzarello, P., Barbato, F. C. T., Bernardini, P., Bi, X. J., Cai, M. S., Casilli, E., Catanzani, E., Chang, J., Chen, D. Y., Chen, J. L., Chen, Z. F., Cui, M. Y., Cui, T. S., Cui, Y. X., Dai, H. T., De-Benedittis, A., De Mitri, I., de Palma, F., Deliyergiyev, M., Di Giovanni, A., Di Santo, M., Ding, Q., Dong, T. K., Dong, Z. X., Donvito, G., Droz, D., Duan, J. L., Duan, K. K., D'Urso, D., Fan, R. R., Fan, Y. Z., Fang, F., Fang, K., Feng, C. Q., Feng, L., Alonso, M. F., Frieden, J. M., Fusco, P., Gao, M., Gargano, F., Gong, K., Gong, Y. Z., Guo, D. Y., Guo, J. H., Han, S. X., Hu, Y. M., Huang, G. S., Huang, X. Y., Huang, Y. Y., Ionica, M., Jiang, L. Y., Jiang, W., Kong, J., Kotenko, A., Kyratzis, D., Lei, S. J., Li, W. L., Li, W. H., Li, X., Li, X. Q., Liang, Y. M., Liu, C. M., Liu, H., Liu, J., Liu, S. B., Liu, Y., Loparco, F., Luo, C. N., Ma, M., Ma, P. X., Ma, T., Ma, X. Y., Marsella, G., Mazziotta, M. N., Mo, D., Salinas, M. M., Niu, X. Y., Pan, X., Parenti, A., Peng, W. X., Peng, X. Y., Perrina, C., Qiao, R., Rao, J. N., Ruina, A., Shangguan, Z., Shen, W. H., Shen, Z. Q., Shen, Z. T., Silveri, L., Song, J. X., Stolpovskiy, M., Su, H., Su, M., Sun, H. R., Sun, Z. Y., Surdo, A., Teng, X. J., Tykhonov, A., Wang, J. Z., Wang, L. G., Wang, S., Wang, S. X., Wang, X. L., Wang, Y., Wang, Y. F., Wang, Y. Z., Wei, D. M., Wei, J. J., Wei, Y. F., Wu, D., Wu, J., Wu, L. B., Wu, S. S., Wu, X., Xia, Z. Q., Xu, E. H., Xu, H. T., Xu, J., Xu, Z. H., Xu, Z. L., Xu, Z. Z., Xue, G. F., Yang, H. B., Yang, P., Yang, Y. Q., Yao, H. J., Yu, Y. H., Yuan, G. W., Yuan, Q., Yue, C., Zang, J. J., Zhang, S. X., Zhang, W. Z., Zhang, Yan, Zhang, Yi., Zhang, Y. J., Zhang, Y. L., Zhang, Y. P., Zhang, Y. Q., Zhang, Z., Zhang, Z. Y., Zhao, C., Zhao, H. Y., Zhao, X. F., Zhou, C. Y., and Zhu, Y.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment, High Energy Physics - Phenomenology, Physics - Space Physics
Abstract: More than a century after the performance of the oil drop experiment, the possible existence of fractionally charged particles FCP still remains unsettled. The search for FCPs is crucial for some extensions of the Standard Model in 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., Comment: 19 pages, 6 figures, accepted by PRD
Published: 2022
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10. Semileptonic $B_c$ decays to $P-$wave charmonium and the nature of $\chi_{c1}(3872)$

Author: Colangelo, P., De Fazio, F., Losacco, N., Loparco, F., and Novoa-Brunet, M.
Subjects: High Energy Physics - Phenomenology
Abstract: The hadronic form factors of $B_c$ semileptonic decays to the $P-$wave charmonium 4-plet can be expressed near the zero-recoil point in terms of universal functions, performing a systematic expansion in QCD in the relative velocity of the heavy quarks and in $1/m_Q$. Such functions are independent of the member of the multiplet involved in the transitions. We present the results of an NLO calculation up to $O(1/m_Q^2)$ classifying the universal functions at this order. We work out a set of relations among the form factors of the same mode and of different modes, which should be reproduced by explicit calculations, reducing the hadronic uncertainty affecting such channels. The approach is also helpful to investigate the debated nature of $\chi_{c1}(3872)$, studying the production in $B_c$ semileptonic decays and comparing it to the modes involving the other $2P$ charmonia., Comment: LaTeX, 36 pages, 5 figures
Published: 2022
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11. Constraints on dark matter scattering with long lived mediators from observations of the Sun with the Fermi Large Area Telescope

Author: Serini, D., Loparco, F., Mazziotta, M. N., De Gaetano, S., Di Venere, L., Gargano, F., Lorusso, L., Panzarini, G., and Pillera, R.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment
Abstract: The Sun represents a promising target for indirect dark matter searches, as dark matter particles from the Galactic halo can be gravitationally trapped in its core or in external orbits, and their annihilations can lead to final states with standard model particles that are able to reach the Earth. In this work we have considered a scenario in which dark matter particles can annihilate into pairs of long-lived mediators, which in turn can escape from the Sun and decay into pairs of gamma rays or into the $b\bar{b}$, $\tau^{+}\tau^{-}$, $\mu^{+}\mu^{-}$ channels, with the production of gamma rays in the final states. All these processes are expected to yield an excess in the energy spectrum of gamma rays towards the Sun. We have therefore analyzed the data collected by the Fermi Large Area Telescope during its first 13.5 years of operation, searching for possible excesses in the solar gamma-ray spectrum. Since no statistically significant excess is found, we have set constraints on the dark matter-nucleon scattering cross sections in both the spin-dependent and spin-independent cases. For all the mediator decay channels explored and for dark matter masses between a few GeV/c${^2}$ and 1 TeV/c${^2}$, we have found that the upper limits on the spin-dependent and spin-independent cross sections are in the ranges from $10^{-45}$ to $10^{-39}$ cm$^{2}$ and from $10^{-47}$ up to $10^{-42}$ cm$^{2}$, respectively., Comment: 16 pages; 7 figures; corresponding authors: D. Serini, F. Loparco and M. N. Mazziotta
Published: 2022
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12. Relations among $B_c \to J/\psi, \eta_c$ form factors

Author: Colangelo, P., De Fazio, F., Loparco, F., Losacco, N., and Novoa-Brunet, M.
Subjects: High Energy Physics - Phenomenology, High Energy Physics - Experiment, High Energy Physics - Lattice
Abstract: We analyze the form factors parametrizing the $B_c \to J/\psi, \eta_c$ matrix elements of the operators in a generalized low-energy $b \to c$ semileptonic Hamiltonian. We consider an expansion in nonrelativistic QCD, classifying the heavy quark spin symmetry breaking terms and expressing the form factors in terms of universal functions in a selected kinematical range. Using as an input the lattice QCD results for the $B_c \to J/\psi$ matrix element of the SM operator, we obtain information on other form factors. The extrapolation to the full kinematical range is also presented., Comment: 32 pages, 4 figures. To appear in JHEP
Published: 2022
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13. Search for new cosmic-ray acceleration sites within the 4FGL catalog Galactic plane sources

Author: Collaboration, Fermi-LAT, Abdollahi, S., Acero, F., Ackermann, M., Baldini, L., Ballet, J., Barbiellini, G., Bastieri, D., Bellazzini, R., Berenji, B., Berretta, A., Bissaldi, E., Blandford, R. D., Bonino, R., Bruel, P., Buson, S., Cameron, R. A., Caputo, R., Caraveo, P. A., Castro, D., Chiaro, G., Cibrario, N., Ciprini, S., Coronado-Blázquez, J., Crnogorcevic, M., Cutini, S., D'Ammando, F., De Gaetano, S., Di Lalla, N., Dirirsa, F., Di Venere, L., Domínguez, A., Fegan, S. J., Fiori, A., Fleischhack, H., Franckowiak, A., Fukazawa, Y., Fusco, P., Gammaldi, V., Gargano, F., Gasparrini, D., Giacchino, F., Giglietto, N., Giordano, F., Giroletti, M., Glanzman, T., Green, D., Grenier, I. A., Grondin, M. -H., Guiriec, S., Gustafsson, M., Harding, A. K., Hays, E., Hewitt, J. W., Horan, D., Hou, X., Jóhannesson, G., Kayanoki, T., Kerr, M., Kuss, M., Larsson, S., Latronico, L., Lemoine-Goumard, M., Li, J., Longo, F., Loparco, F., Lubrano, P., Maldera, S., Malyshev, D., Manfreda, A., Martí-Devesa, G., Mazziotta, M. N., Mereu, I., Michelson, P. F., Mirabal, N., Mitthumsiri, W., Mizuno, T., Monzani, M. E., Morselli, A., Moskalenko, I. V., Nuss, E., Omodei, N., Orienti, M., Orlando, E., Ormes, J. F., Paneque, D., Pei, Z., Persic, M., Pesce-Rollins, M., Pillera, R., Poon, H., Porter, T. A., Principe, G., Rainò, S., Rando, R., Rani, B., Razzano, M., Razzaque, S., Reimer, A., Reimer, O., Reposeur, T., Sánchez-Conde, M., Parkinson, P. M. Saz, Scotton, L., Serini, D., Sgrò, C., Siskind, E. J., Spandre, G., Spinelli, P., Sueoka, K., Suson, D. J., Tajima, H., Tak, D., Thayer, J. B., Torres, D. F., Troja, E., Valverde, J., Wadiasingh, Z., Wood, K., and Zaharijas, G.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Cosmic rays are mostly composed of protons accelerated to relativistic speeds. When those protons encounter interstellar material, they produce neutral pions which in turn decay into gamma rays. This offers a compelling way to identify the acceleration sites of protons. A characteristic hadronic spectrum, with a low-energy break around 200 MeV, was detected in the gamma-ray spectra of four Supernova Remnants (SNRs), IC 443, W44, W49B and W51C, with the Fermi Large Area Telescope. This detection provided direct evidence that cosmic-ray protons are (re-)accelerated in SNRs. Here, we present a comprehensive search for low-energy spectral breaks among 311 4FGL catalog sources located within 5 degrees from the Galactic plane. Using 8 years of data from the Fermi Large Area Telescope between 50 MeV and 1 GeV, we find and present the spectral characteristics of 56 sources with a spectral break confirmed by a thorough study of systematic uncertainty. Our population of sources includes 13 SNRs for which the proton-proton interaction is enhanced by the dense target material; the high-mass gamma-ray binary LS~I +61 303; the colliding wind binary eta Carinae; and the Cygnus star-forming region. This analysis better constrains the origin of the gamma-ray emission and enlarges our view to potential new cosmic-ray acceleration sites., Comment: Accepted for publication in The Astrophysical Journal
Published: 2022
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14. A Gamma-ray Pulsar Timing Array Constrains the Nanohertz Gravitational Wave Background

Author: Ajello, M., Atwood, W. B., Baldini, L., Ballet, J., Barbiellini, G., Bastieri, D., Bellazzini, R., Berretta, A., Bhattacharyya, B., Bissaldi, E., Blandford, R. D., Bloom, E., Bonino, R., Bruel, P., Buehler, R., Burns, E., Buson, S., Cameron, R. A., Caraveo, P. A., Cavazzuti, E., Cibrario, N., Ciprini, S., Clark, C. J., Cognard, I., Coronado-Blázquez, J., Crnogorcevic, M., Cromartie, H., Crowter, K., Cutini, S., D'Ammando, F., Gaetano, S. D., Palma, F. d., Digel, S. W., Lalla, N. D., Dirirsa, F. Fan., Venere, L. D., Domínguez, A., Ferrara, E. C., Fiori, A., Franckowiak, A., Fukazawa, Y., Funk, S., Fusco, P., Gammaldi, V., Gargano, F., Gasparrini, D., Giglietto, N., Giordano, F., Giroletti, M., Green, D., Grenier, I. A., Guillemot, L., Guiriec, S., Gustafsson, M., Harding, A. K., Hays, E., Hewitt, J. W., Horan, D., Hou, X., Jóhannesson, G., Keith, M. J., Kerr, M., Kramer, M., Kuss, M., Larsson, S., Latronico, L., Li, J., Longo, F., Loparco, F., Lovellette, M. N., Lubrano, P., Maldera, S., Manfreda, A., Martí-Devesa, G., Mazziotta, M. N., Mereu, I., Michelson, P. F., Mirabal, N., Mitthumsiri, W., Mizuno, T., Monzani, M. E., Morselli, A., Negro, M., Nieder, L., Ojha, R., Omodei, N., Orienti, M., Orlando, E., Ormes, J. F., Paneque, D., Parthasarathy, A., Pei, Z., Persic, M., Pesce-Rollins, M., Pillera, R., Poon, H., Porter, T. A., Principe, G., Racusin, J. L., Rainò, S., Rando, R., Rani, B., Ransom, S. M., Ray, P. S., Razzano, M., Razzaque, S., Reimer, A., Reimer, O., Roy, J., Sánchez-Conde, M., Parkinson, P. M. Sa., Scargle, J., Scotton, L., Serini, D., Sgrò, C., Siskind, E. J., Smith, D. A., Spandre, G., Spiewak, R., Spinelli, P., Stairs, I., Suson, D. J., Swihart, S. J., Tabassum, S., Thayer, J. B., Theureau, G., Torres, D. F., Troja, E., Valverde, J., Wadiasingh, Z., Wood, K., and Zaharijas, G.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: After large galaxies merge, their central supermassive black holes are expected to form binary systems whose orbital motion generates a gravitational wave background (GWB) at nanohertz frequencies. Searches for this background utilize pulsar timing arrays, which perform long-term monitoring of millisecond pulsars (MSPs) at radio wavelengths. We use 12.5 years of Fermi Large Area Telescope data to form a gamma-ray pulsar timing array. Results from 35 bright gamma-ray pulsars place a 95\% credible limit on the GWB characteristic strain of $1.0\times10^{-14}$ at 1 yr$^{-1}$, which scales as the observing time span $t_{\mathrm{obs}}^{-13/6}$. This direct measurement provides an independent probe of the GWB while offering a check on radio noise models., Comment: 3 figures in the main text. 3 figures and 8 tables are in the supplementary material
Published: 2022
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15. Measurement of the angular correlation between the two gamma rays emitted in the radioactive decays of a $^{60}$Co source with two NaI(Tl) scintillator

Author: Amato, E. C., Anelli, A., Barbieri, M., Cataldi, D., Cellamare, V., Cerasole, D., Conserva, F., De Gaetano, S., Depalo, D., Digennaro, A., Fiorente, E., Gargano, F., Gatti, D., Loizzo, P., Loparco, F., Mele, O., Nicassio, N., Perfetto, G., Pillera, R., Pirlo, R., Schygulla, E., and Troiano, D.
Subjects: Physics - Physics Education, Physics - Instrumentation and Detectors
Abstract: We implemented a didactic experiment to study the angular correlation between the two gamma rays emitted in typical $^{60}$Co radioactive decays. We used two NaI(Tl) scintillators, already available in our laboratory, and a low-activity $^{60}$Co source. The detectors were mounted on two rails, with the source at their center. The first rail was fixed, while the second could be rotated around the source. We performed several measurements by changing the angle between the two scintillators in the range from $90^\circ$ to $180^\circ$. Dedicated background runs were also performed, removing the source from the experimental setup. We found that the signal rate increases with the angular separation between the two scintillators, with small discrepancies from the theoretical expectations., Comment: 15 pages, 12 figures
Published: 2022
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16. An Imaging Calorimeter prototype with WLS fibers and LYSO crystal

Author: Lorusso, L., Giliberti, M., Liguori, A., Loparco, F., Mazziotta, M.N., Panzarini, G., and Pillera, R.
Published: 2024
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17. On the decay mode Λb → Xsγ

Author: Colangelo, P., De Fazio, F., and Loparco, F.
Published: 2023
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18. Fermi Large Area Telescope Performance After 10 Years Of Operation

Author: The Fermi LAT Collaboration, Ajello, M., Atwood, W. B., Axelsson, M., Bagagli, R., Bagni, M., Baldini, L., Bastieri, D., Bellardi, F., Bellazzini, R., Bissaldi, E., Bloom, E. D., Bonino, R., Bregeon, J., Brez, A., Bruel, P., Buehler, R., Buson, S., Cameron, R. A., Caraveo, P. A., Cavazzuti, E., Ceccanti, M., Chen, S., Cheung, C. C., Ciprini, S., Cognard, I., Cohen-Tanugi, J., Cutini, S., D'Ammando, F., Luque, P. de la Torre, de Palma, F., Digel, S. W., Dirirsa, F., Di Lalla, N., Di Venere, L., Domínguez, A., Fabiani, D., Ferrara, E. C., Fiori, A., Foglia, G., Fukazawa, Y., Fusco, P., Gargano, F., Gasparrini, D., Giroletti, M., Glanzman, T., Green, D., Griffin, S., Grondin, M. -H., Grove, J. E., Guillemot, L., Guiriec, S., Gustafsson, M., Hays, E., Horan, D., Jóhannesson, G., Johnson, T. J., Kamae, T., Kerr, M., Kuss, M., Larsson, S., Latronico, L., Lemoine-Goumard, M., Li, J., Liodakis, I., Longo, F., Loparco, F., Lovellette, M. N., Lubrano, P., Maldera, S., Manfreda, A., Martí-Devesa, G., Mazziotta, M. N., Menon, N., Mereu, I., Meyer, M., Michelson, P. F., Minuti, M., Mitthumsiri, W., Mizuno, T., Mongelli, M., Monzani, M. E., Moskalenko, I. V., Negro, M., Nuss, E., Ojha, R., Orienti, M., Orlando, E., Paccagnella, A., Paliya, V. S., Paneque, D., Pei, Z., Perkins, J. S., Pesce-Rollins, M., Pinchera, M., Piron, F., Poon, H., Porter, T. A., Primavera, R., Principe, G., Racusin, J. L., Rainò, S., Rando, R., Rani, B., Rapposelli, E., Razzano, M., Razzaque, S., Reimer, A., Reimer, O., Russell, J. J., Saggini, N., Parkinson, P. M. Saz, Scolieri, N., Serini, D., Sgrò, C., Siskind, E. J., Smith, D. A., Spandre, G., Spinelli, P., Suson, D. J., Tajima, H., Thayer, J. G., Thompson, D. J., Tibaldo, L., Torres, D. F., Tosti, G., Valverde, J., Vigiani, L., and Zaharijas, G.
Subjects: Astrophysics - Instrumentation and Methods for Astrophysics
Abstract: The Large Area Telescope (LAT), the primary instrument for the Fermi Gamma-ray Space Telescope (Fermi) mission, is an imaging, wide field-of-view, high-energy gamma-ray telescope, covering the energy range from 30 MeV to more than 300 GeV. We describe the performance of the instrument at the 10-year milestone. LAT performance remains well within the specifications defined during the planning phase, validating the design choices and supporting the compelling case to extend the duration of the Fermi mission. The details provided here will be useful when designing the next generation of high-energy gamma-ray observatories., Comment: 60 pages, 28 figures. Published in ApJS
Published: 2021
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19. Catalog of Long-Term Transient Sources in the First 10 Years of Fermi-LAT Data

Author: Baldini, L., Ballet, J., Bastieri, D., Gonzalez, J. Becerra, Bellazzini, R., Berretta, A., Bissaldi, E., Blandford, R. D., Bloom, E. D., Bonino, R., Bottacini, E., Bruel, P., Buson, S., Cameron, R. A., Caraveo, P. A., Cavazzuti, E., Chen, S., Chiaro, G., Ciangottini, D., Ciprini, S., Orestano, P. Cristarella, Crnogorcevic, M., Cutini, S., D'Ammando, F., Luque, P. de la Torre, de Palma, F., Digel, S. W., Di Lalla, N., Dirirsa, F., Di Venere, L., Domínguez, A., Fiori, A., Fleischhack, H., Franckowiak, A., Fukazawa, Y., Funk, S., Fusco, P., Gargano, F., Gasparrini, D., Germani, S., Giglietto, N., Giordano, F., Giroletti, M., Green, D., Grenier, I. A., Griffin, S., Guiriec, S., Gustafsson, M., Hewitt, J. W., Horan, D., Imazawa, R., Jóhannesson, G., Kerr, M., Kocevski, D., Kuss, M., Larsson, S., Latronico, L., Li, J., Liodakis, I., Longo, F., Loparco, F., Lovellette, M. N., Lubrano, P., Maldera, S., Manfreda, A., Martí-Devesa, G., Matake, H., Mazziotta, M. N., Mereu, I., Meyer, M., Mirabal, N., Mitthumsiri, W., Mizuno, T., Monzani, M. E., Morselli, A., Moskalenko, I. V., Nagasawa, S., Negro, M., Ojha, R., Orienti, M., Orlando, E., Palatiello, M., Paliya, V., Paneque, D., Pei, Z., Persic, M., Pesce-Rollins, M., Petrosian, V., Poon, H., Porter, T. A., Principe, G., Racusin, J. L., Rainò, S., Rando, R., Rani, B., Razzano, M., Razzaque, S., Reimer, A., Reimer, O., Parkinson, P. M. Saz, Scotton, L., Serini, D., Sgrò, C., Siskind, E. J., Spandre, G., Spinelli, P., Suson, D. J., Tajima, H., Tak, D., Torres, D. F., Tosti, G., Troja, E., Wood, K., Yassine, M., and Zaharijas, G.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We present the first Fermi Large Area Telescope (LAT) catalog of long-term $\gamma$-ray transient sources (1FLT). This comprises sources that were detected on monthly time intervals during the first decade of Fermi-LAT operations. The monthly time scale allows us to identify transient and variable sources that were not yet reported in other Fermi-LAT catalogs. The monthly datasets were analyzed using a wavelet-based source detection algorithm that provided the candidate new transient sources. The search was limited to the extragalactic regions of the sky to avoid the dominance of the Galactic diffuse emission at low Galactic latitudes. The transient candidates were then analyzed using the standard Fermi-LAT Maximum Likelihood analysis method. All sources detected with a statistical significance above 4$\sigma$ in at least one monthly bin were listed in the final catalog. The 1FLT catalog contains 142 transient $\gamma$-ray sources that are not included in the 4FGL-DR2 catalog. Many of these sources (102) have been confidently associated with Active Galactic Nuclei (AGN): 24 are associated with Flat Spectrum Radio Quasars; 1 with a BL Lac object; 70 with Blazars of Uncertain Type; 3 with Radio Galaxies; 1 with a Compact Steep Spectrum radio source; 1 with a Steep Spectrum Radio Quasar; 2 with AGN of other types. The remaining 40 sources have no candidate counterparts at other wavelengths. The median $\gamma$-ray spectral index of the 1FLT-AGN sources is softer than that reported in the latest Fermi-LAT AGN general catalog. This result is consistent with the hypothesis that detection of the softest $\gamma$-ray emitters is less efficient when the data are integrated over year-long intervals., Comment: 41 pages, 17 figures, 7 tables; Accepted by ApJS on 24 May 2021; Contact Authors: I. Mereu, S. Cutini, E. Cavazzuti, G. Tosti
Published: 2021
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20. Measurement of the cosmic ray helium energy spectrum from 70 GeV to 80 TeV with the DAMPE space mission

Author: Alemanno, F., An, Q., Azzarello, P., Barbato, F. C. T., Bernardini, P., Bi, X. J., Cai, M. S., Catanzani, E., Chang, J., Chen, D. Y., Chen, J. L., Chen, Z. F., Cui, M. Y., Cui, T. S., Cui, Y. X., Dai, H. T., D'Amone, A., De Benedittis, A., De Mitri, I., de Palma, F., Deliyergiyev, M., Di Santo, M., Dong, T. K., Dong, Z. X., Donvito, G., Droz, D., Duan, J. L., Duan, K. K., D'Urso, D., Fan, R. R., Fan, Y. Z., Fang, K., Fang, F., Feng, C. Q., Feng, L., Fusco, P., Gao, M., Gargano, F., Gong, K., Gong, Y. Z., Guo, D. Y., Guo, J. H., Guo, X. L., Han, S. X., Hu, Y. M., Huang, G. S., Huang, X. Y., Huang, Y. Y., Ionica, M., Jiang, W., Kong, J., Kotenko, A., Kyratzis, D., Lei, S. J., Li, S., Li, W. L., Li, X., Li, X. Q., Liang, Y. M., Liu, C. M., Liu, H., Liu, J., Liu, S. B., Liu, W. Q., Liu, Y., Loparco, F., Luo, C. N., Ma, M., Ma, P. X., Ma, T., Ma, X. Y., Marsella, G., Mazziotta, M. N., Mo, D., Niu, X. Y., Pan, X., Parenti, A., Peng, W. X., Peng, X. Y., Perrina, C., Qiao, R., Rao, J. N., Ruina, A., Salinas, M. M., Shang, G. Z., Shen, W. H., Shen, Z. Q., Shen, Z. T., Silveri, L., Song, J. X., Stolpovskiy, M., Su, H., Su, M., Sun, Z. Y., Surdo, A., Teng, X. J., Tykhonov, A., Wang, H., Wang, J. Z., Wang, L. G., Wang, S., Wang, X. L., Wang, Y., Wang, Y. F., Wang, Y. Z., Wang, Z. M., Wei, D. M., Wei, J. J., Wei, Y. F., Wen, S. C., Wu, D., Wu, J., Wu, L. B., Wu, S. S., Wu, X., Xia, Z. Q., Xu, H. T., Xu, Z. H., Xu, Z. L., Xu, Z. Z., Xue, G. F., Yang, H. B., Yang, P., Yang, Y. Q., Yao, H. J., Yu, Y. H., Yuan, G. W., Yuan, Q., Yue, C., Zang, J. J., Zhang, F., Zhang, S. X., Zhang, W. Z., Zhang, Y., Zhang, Y. J., Zhang, Y. L., Zhang, Y. P., Zhang, Y. Q., Zhang, Z., Zhang, Z. Y., Zhao, C., Zhao, H. Y., Zhao, X. F., Zhou, C. Y., and Zhu, Y.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment
Abstract: 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 $4.3\sigma$. 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., Comment: 11 pages, 13 figures, published in Phys. Rev. Lett. Add one more digit for first three columns in Table S2
Published: 2021
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21. Markov chain Monte Carlo analyses of the flux ratios of B, Be and Li with the DRAGON2 code

Author: Luque, P. De La Torre, Mazziotta, M. N., Loparco, F., Gargano, F., and Serini, D.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Recent cosmic-ray measurements are challenging our models of propagation in the Galaxy. A good characterization of the secondary cosmic rays (B, Be, Li and sub-iron species) is crucial to constrain these models and exploit the precision of modern CR experiments. In this work, a Markov chain Monte Carlo analysis has been implemented to fit the experimental flux ratios between B, Be and Li and their flux ratios to the primary nuclei C and O. We have fitted the data using two different parametrizations for the spallation cross sections. The uncertainties in the evaluation of the spectra of these secondary cosmic rays, due to spallation cross sections, have been considered by introducing scale factors as nuisance parameters. We have also tested two different formulations for the diffusion coefficient, which differ in the origin of the high energy hardening of cosmic rays. Additionally, two different approaches are used to scale the cross sections, one based on a combined analysis of all the species ("combined" analysis) and the other reproducing the high energy spectra of the secondary-to-secondary flux ratios of Be/B, Li/B, Li/Be ("scaled" analysis). This allows us to make a better comparison between the propagation parameters inferred from the cross sections parametrizations tested in this work. This novel analysis has been successfully implemented using the numerical code DRAGON2 to reproduce the cosmic-ray nuclei data up to $Z=14$ from the AMS-02 experiment. It is found that the ratios of Li favor a harder spectral index of the diffusion coefficient, but compatible with the other ratios inside the observed $2\sigma$ uncertainties. In addition, it is shown that, including these scale factors, the secondary-to-primary flux ratios can be simultaneously reproduced., Comment: 27 pages, 10 figures, 9 tables
Published: 2021
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22. Role of $B_c^+ \to B_{s,d}^{(*)} \, \bar \ell \, \nu_\ell$ in the Standard Model and in the search for BSM signals

Author: Colangelo, P., De Fazio, F., and Loparco, F.
Subjects: High Energy Physics - Phenomenology, High Energy Physics - Experiment, High Energy Physics - Lattice
Abstract: The decays $B_c^+ \to B_{a} \bar \ell \nu_\ell$ and $B_c^+ \to B_{a}^{*}(\to B_a \gamma) \bar \ell \nu_\ell$, with $a=s,d$ and $\ell=e,\mu$, are studied in the Standard Model (SM) and in the extension based on the low-energy Hamiltonian comprising the full set of dimension-$6$ semileptonic $c \to s,d$ operators with left-handed neutrinos. Tests of $\mu/e$ universality are investigated using such modes. The heavy quark spin symmetry is applied to relate the relevant hadronic matrix elements and to exploit lattice QCD results on $B_c$ form factors. Optimized observables are selected, and the pattern of their correlations is studied to identify the effects of the various operators in the extended low-energy Hamiltonian., Comment: LaTex, 15 pages, 17 figures. Figures and references added, version to appear in PRD
Published: 2021
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23. Search for dark matter signatures in the gamma-ray emission towards the Sun with the Fermi Large Area Telescope

Author: Mazziotta, M. N., Loparco, F., Serini, D., Cuoco, A., Luque, P. De La Torre, Gargano, F., and Gustafsson, M.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment
Abstract: Dark matter particles from the Galactic halo can be gravitationally trapped in the solar core or in external orbits. The enhanced density of dark matter particles either in the solar core or in external orbits can result in the annihilation of these particles producing gamma rays via long-lived intermediate states or directly outside the Sun, respectively. These processes would yield characteristic features in the energy spectrum of the subsequent gamma rays, i.e., a box-like or line-like shaped feature, respectively. We have performed a dedicated analysis using a 10-years sample of gamma-ray events from the Sun collected by the Fermi Large Area Telescope searching for spectral features in the energy spectrum as a signature of dark matter annihilation. In the scenario of gamma-ray production via long-lived mediators we have also evaluated the dark matter-nucleon spin-dependent and spin-independent scattering cross section constraints from the flux limits in a dark matter mass range from 3 GeV/c$^2$ up to about 1.8 TeV/c$^2$. In the mass range up to about 150 GeV/c$^2$ the limits are in the range $10^{-46} - 10^{-45}$ cm$^{2}$ for the spin-dependent scattering and in the range $10^{-48} - 10^{-47}$ cm$^{2}$ for the spin-independent case. The range of variation depends on the decay length of the mediator., Comment: 12 pages; 7 figures; accepted by PRD
Published: 2020
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24. Cosmic-ray interactions with the Sun using the FLUKA code

Author: Mazziotta, M. N., Luque, P. De La Torre, Di Venere, L., Fassò, A., Ferrari, A., Loparco, F., Sala, P. R., and Serini, D.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The interactions of cosmic rays with the solar atmosphere produce secondary particle which can reach the Earth. In this work we present a comprehensive calculation of the yields of secondary particles as gamma-rays, electrons, positrons, neutrons and neutrinos performed with the FLUKA code. We also estimate the intensity at the Sun and the fluxes at the Earth of these secondary particles by folding their yields with the intensities of cosmic rays impinging on the solar surface. The results are sensitive on the assumptions on the magnetic field nearby the Sun and to the cosmic-ray transport in the magnetic field in the inner solar system., Comment: Update version of the top left plot on Fig. 12 due to a wrong scale factor used in the script which produced the plot
Published: 2020
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25. A search for dark matter cosmic-ray electrons and positrons from the Sun with the Fermi Large Area Telescope

Author: Cuoco, A., Luque, P. De La Torre, Gargano, F., Gustafsson, M., Loparco, F., Mazziotta, M. N., and Serini, D.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Phenomenology
Abstract: We use 7 years of electron and positron Fermi-LAT data to search for a possible excess in the direction of the Sun in the energy range from 42 GeV to 2 TeV. In the absence of a positive signal we derive flux upper limits which we use to constrain two different dark matter (DM) models producing $e^+ e^-$ fluxes from the Sun. In the first case we consider DM model being captured by the Sun due to elastic scattering and annihilation into $e^+ e^-$ pairs via a long-lived light mediator that can escape the Sun. In the second case we consider instead a model where DM density is enhanced around the Sun through inelastic scattering and the DM annihilates directly into $e^+ e^-$ pairs. In both cases we perform an optimal analysis, searching specifically for the energy spectrum expected in each case, i.e., a box-like shaped and line-like shaped spectrum respectively. No significant signal is found and we can place limits on the spin-independent cross-section in the range from $10^{-46}~cm^2$ to $10^{-44}~cm^2$ and on the spin-dependent cross-section in the range from $10^{-43}~cm^2$ to $10^{-41}~cm^2$. In the case of inelastic scattering the limits on the cross-section are in the range from $10^{-43}~cm^2$ to $10^{-41}~cm^2$. The limits depend on the life time of the mediator (elastic case) and on the mass splitting value (inelastic case), as well as on the assumptions made for the size of the deflections of electrons and positrons in the interplanetary magnetic field., Comment: 12 pages; 6 figures; Accepted by PRD for publication
Published: 2019
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26. Transition radiation detectors for hadron separation in the forward direction of LHC experiments

Author: Albrow, M., Belyaev, N., Cherry, M., Doronin, S., Fusco, P., Gargano, F., Konovalov, S., Loparco, F., Mazziotta, M.N., Ponomarenko, D., Rembser, C., Romaniouk, A., Smirnov, S., Smirnov, Yu., Spinelli, P., Sultanaliyeva, L., Teterin, P., Tikhomirov, V., Vorobev, K., and Zhukov, K.
Published: 2023
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27. Measurement of the cosmic-ray proton spectrum from 40 GeV to 100 TeV with the DAMPE satellite

Author: An, Q., Asfandiyarov, R., Azzarello, P., Bernardini, P., Bi, X. J., Cai, M. S., Chang, J., Chen, D. Y., Chen, H. F., Chen, J. L., Chen, W., Cui, M. Y., Cui, T. S., Dai, H. T., D'Amone, A., De Benedittis, A., De Mitri, I., Di Santo, M., Ding, M., Dong, T. K., Dong, Y. F., Dong, Z. X., Donvito, G., Droz, D., Duan, J. L., Duan, K. K., D'Urso, D., Fan, R. R., Fan, Y. Z., Fang, F., Feng, C. Q., Feng, L., Fusco, P., Gallo, V., Gan, F. J., Gao, M., Gargano, F., Gong, K., Gong, Y. Z., Guo, D. Y., Guo, J. H., Guo, X. L., Han, S. X., Hu, Y. M., Huang, G. S., Huang, X. Y., Huang, Y. Y., Ionica, M., Jiang, W., Jin, X., Kong, J., Lei, S. J., Li, S., Li, W. L., Li, X., Li, X. Q., Li, Y., Liang, Y. F., Liang, Y. M., Liao, N. H., Liu, C. M., Liu, H., Liu, J., Liu, S. B., Liu, W. Q., Liu, Y., Loparco, F., Luo, C. N., Ma, M., Ma, P. X., Ma, S. Y., Ma, T., Ma, X. Y., Marsella, G., Mazziotta, M. N., Mo, D., Niu, X. Y., Pan, X., Peng, W. X., Peng, X. Y., Qiao, R., Rao, J. N., Salinas, M. M., Shang, G. Z., Shen, W. H., Shen, Z. Q., Shen, Z. T., Song, J. X., Su, H., Su, M., Sun, Z. Y., Surdo, A., Teng, X. J., Tykhonov, A., Vitillo, S., Wang, C., Wang, H., Wang, H. Y., Wang, J. Z., Wang, L. G., Wang, Q., Wang, S., Wang, X. H., Wang, X. L., Wang, Y. F., Wang, Y. P., Wang, Y. Z., Wang, Z. M., Wei, D. M., Wei, J. J., Wei, Y. F., Wen, S. C., Wu, D., Wu, J., Wu, L. B., Wu, S. S., Wu, X., Xi, K., Xia, Z. Q., Xu, H. T., Xu, Z. H., Xu, Z. L., Xu, Z. Z., Xue, G. F., Yang, H. B., Yang, P., Yang, Y. Q., Yang, Z. L., Yao, H. J., Yu, Y. H., Yuan, Q., Yue, C., Zang, J. J., Zhang, F., Zhang, J. Y., Zhang, J. Z., Zhang, P. F., Zhang, S. X., Zhang, W. Z., Zhang, Y., Zhang, Y. J., Zhang, Y. L., Zhang, Y. P., Zhang, Y. Q., Zhang, Z., Zhang, Z. Y., Zhao, H., Zhao, H. Y., Zhao, X. F., Zhou, C. Y., Zhou, Y., Zhu, X., Zhu, Y., and Zimmer, S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The precise measurement of the spectrum of protons, the most abundant component of the cosmic radiation, is necessary to understand the source and acceleration of cosmic rays in the Milky Way. This work reports the measurement of the cosmic ray proton fluxes with kinetic energies from 40 GeV to 100 TeV, with two and a half years of data recorded by the DArk Matter Particle Explorer (DAMPE). This is the first time an experiment directly measures the cosmic ray protons up to ~100 TeV with a high statistics. The measured spectrum confirms the spectral hardening found by previous experiments and reveals a softening at ~13.6 TeV, with the spectral index changing from ~2.60 to ~2.85. Our result suggests the existence of a new spectral feature of cosmic rays at energies lower than the so-called knee, and sheds new light on the origin of Galactic cosmic rays., Comment: 37 pages, 5 figures, published in Science Advances
Published: 2019
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28. Fermi and Swift Observations of GRB 190114C: Tracing the Evolution of High-Energy Emission from Prompt to Afterglow

Author: Ajello, M., Arimoto, M., Axelsson, M., Baldini, L., Barbiellini, G., Bastieri, D., Bellazzini, R., Berretta, A., Bissaldi, E., Blandford, R. D., Bonino, R., Bottacini, E., Bregeon, J., Bruel, P., Buehler, R., Burns, E., Buson, S., Cameron, R. A., Caputo, R., Caraveo, P. A., Cavazzuti, E., Chen, S., Chiaro, G., Ciprini, S., Cohen-Tanugi, J., Costantin, D., Cutini, S., D'Ammando, F., DeKlotz, M., Luque, P. de la Torre, de Palma, F., Desai, A., Di Lalla, N., Di Venere, L., Dirirsa, F. Fana, Fegan, S. J., Franckowiak, A., Fukazawa, Y., Funk, S., Fusco, P., Gargano, F., Gasparrini, D., Giglietto, N., Gill, R., Giordano, F., Giroletti, M., Granot, J., Green, D., Grenier, I. A., Grondin, M. H., Guiriec, S., Hays, E., Horan, D., Jóhannesson, G., Kocevski, D., Kovac'evic', M., Kuss, M., Larsson, S., Latronico, L., Lemoine-Goumard, M., Li, J., Liodakis, I., Longo, F., Loparco, F., Lovellette, M. N., Lubrano, P., Maldera, S., Malyshev, D., Manfreda, A., Martí-Devesa, G., Mazziotta, M. N., McEnery, J. E., Mereu, I., Meyer, M., Michelson, P. F., Mitthumsiri, W., Mizuno, T., Monzani, M. E., Moretti, E., Morselli, A., Moskalenko, I. V., Negro, M., Nuss, E., Omodei, N., Orienti, M., Orlando, E., Palatiello, M., Paliya, V. S., Paneque, D., Pei, Z., Persic, M., Pesce-Rollins, M., Petrosian, V., Piron, F., Poon, H., Porter, T. A., Principe, G., Racusin, J. L., Rainò, S., Rando, R., Rani, B., Razzano, M., Razzaque, S., Reimer, A., Reimer, O., Ryde, F., Parkinson, P. M. Saz, Serini, D., Sgrò, C., Siskind, E. J., Spandre, G., Spinelli, P., Tajima, H., Takagi, K., Takahashi, M. N., Tak, D., Thayer, J. B., Thompson, D. J., Torres, D. F., Troja, E., Valverde, J., Van Klaveren, B., Wood, K., Yassine, M., Zaharijas, G., Bhat, P. N., Briggs, M. S., Cleveland, W., Giles, M., Goldstein, A., Hui, M., Malacaria, C., Preece, R., Roberts, O., Veres, P., von Kienlin, A., Cenko, S. B., O'Brien, P., Beardmore, A. P., Lien, A., Osborne, J. P., Tohuvavohu, A., D'Elia, V., D'A, A., Perri, M., Gropp, J., Klingler, N., Capalbi, M., Tagliaferri, G., and Stamatikos, M.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We report on the observations of gamma-ray burst (GRB) 190114C by the Fermi Gamma-ray Space Telescope and the Neil Gehrels Swift Observatory. The early-time observations reveal multiple emission components that evolve independently, with a delayed power-law component that exhibits significant spectral attenuation above 40 MeV in the first few seconds of the burst. This power-law component transitions to a harder spectrum that is consistent with the afterglow emission observed at later times. This afterglow component is clearly identifiable in the GBM and BAT light curves as a slowly fading emission component on which the rest of the prompt emission is superimposed. As a result, we are able to constrain the transition from internal shock to external shock dominated emission. We find that the temporal and spectral evolution of the broadband afterglow emission can be well modeled as synchrotron emission from a forward shock propagating into a wind-like circumstellar environment and find that high-energy photons observed by Fermi LAT are in tension with the theoretical maximum energy that can be achieved through synchrotron emission from a shock. These violations of the maximum synchrotron energy are further compounded by the detection of very high energy (VHE) emission above 300 GeV by MAGIC concurrent with our observations. We conclude that the observations of VHE photons from GRB 190114C necessitates either an additional emission mechanism at very high energies that is hidden in the synchrotron component in the LAT energy range, an acceleration mechanism that imparts energy to the particles at a rate that is faster than the electron synchrotron energy loss rate, or revisions of the fundamental assumptions used in estimating the maximum photon energy attainable through the synchrotron process., Comment: 24 pages, 9 figures, Accepted to ApJ
Published: 2019
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29. The on-orbit calibration of DArk Matter Particle Explorer

Author: Ambrosi, G., An, Q., Asfandiyarov, R., Azzarello, P., Bernardini, P., Cai, M. S., Caragiulo, M., Chang, J., Chen, D. Y., Chen, H. F., Chen, J. L., Chen, W., Cui, M. Y., Cui, T. S., Dai, H. T., D'Amone, A., De Benedittis, A., De Mitri, I., Ding, M., Di Santo, M., Dong, J. N., Dong, T. K., Dong, Y. F., Dong, Z. X., Droz, D., Duan, K. K., Duan, J. L., D'Urso, D., Fan, R. R., Fan, Y. Z., Fang, F., Feng, C. Q., Feng, L., Fusco, P., Gallo, V., Gan, F. J., Gao, M., Gao, S. S., Gargano, F., Garrappa, S., Gong, K., Gong, Y. Z., Guo, J. H., Hu, Y. M., Huang, G. S., Huang, Y. Y., Ionica, M., Jiang, D., Jiang, W., Jin, X., Kong, J., Lei, S. J., Li, S., Li, X., Li, W. L., Li, Y., Liang, Y. F., Liang, Y. M., Liao, N. H., Liu, C. M., Liu, H., Liu, J., Liu, S. B., Liu, W. Q., Liu, Y., Loparco, F., Ma, M., Ma, P. X., Ma, S. Y., Ma, T., Ma, X. Q., Ma, X. Y., Marsella, G., Mazziotta, M. N., Mo, D., Niu, X. Y., Pan, X., Peng, X. Y., Peng, W. X., Qiao, R., Rao, J. N., Salinas, M. M., Shang, G. Z., Shen, W. H., Shen, Z. Q., Shen, Z. T., Song, J. X., Su, H., Su, M., Sun, Z. Y., Surdo, A., Teng, X. J., Tian, X. B., Tykhonov, A., Vitillo, S., Wang, C., Wang, H., Wang, H. Y., Wang, J. Z., Wang, L. G., Wang, Q., Wang, S., Wang, X. H., Wang, X. L., Wang, Y. F., Wang, Y. P., Wang, Y. Z., Wang, Z. M., Wen, S. C., Wei, D. M., Wei, J. J., Wei, Y. F., Wu, D., Wu, J., Wu, L. B., Wu, S. S., Wu, X., Xi, K., Xia, Z. Q., Xin, Y. L., Xu, H. T., Xu, Z. H., Xu, Z. L., Xu, Z. Z., Xue, G. F., Yang, H. B., Yang, P., Yang, Y. Q., Yang, Z. L., Yao, H. J., Yu, Y. H., Yuan, Q., Yue, C., Zang, J. J., Zhang, D. L., Zhang, F., Zhang, J. B., Zhang, J. Y., Zhang, J. Z., Zhang, L., Zhang, P. F., Zhang, S. X., Zhang, W. Z., Zhang, Y., Zhang, Y. J., Zhang, Y. Q., Zhang, Y. L., Zhang, Y. P., Zhang, Z., Zhang, Z. Y., Zhao, H., Zhao, H. Y., Zhao, X. F., Zhou, C. Y., Zhou, Y., Zhu, X., Zhu, Y., and Zimmer, S.
Subjects: Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment
Abstract: The DArk Matter Particle Explorer (DAMPE), a satellite-based cosmic ray and gamma-ray detector, was launched on December 17, 2015, and began its on-orbit operation on December 24, 2015. In this work we document the on-orbit calibration procedures used by DAMPE and report the calibration results of the Plastic Scintillator strip Detector (PSD), the Silicon-Tungsten tracKer-converter (STK), the BGO imaging calorimeter (BGO), and the Neutron Detector (NUD). The results are obtained using Galactic cosmic rays, bright known GeV gamma-ray sources, and charge injection into the front-end electronics of each sub-detector. The determination of the boundary of the South Atlantic Anomaly (SAA), the measurement of the live time, and the alignments of the detectors are also introduced. The calibration results demonstrate the stability of the detectors in almost two years of the on-orbit operation.
Published: 2019
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30. Probing New Physics with $\bar B \to \rho(770) \, \ell^- \bar \nu_\ell$ and $\bar B \to a_1(1260) \, \ell^- \bar \nu_\ell$

Author: Colangelo, P., De Fazio, F., and Loparco, F.
Subjects: High Energy Physics - Phenomenology, High Energy Physics - Experiment, High Energy Physics - Lattice
Abstract: The $B$ meson semileptonic modes to $\rho(770)$ and $a_1 (1260)$ are useful to pin down possible non Standard Model effects. The 4d differential $\bar B \to \rho(\pi \pi) \ell^- \bar \nu_\ell$ and $ \bar B \to a_1 (\rho \pi) \ell^- \bar \nu_\ell$ decay distributions are computed in SM and in extensions involving new Lepton Flavour Universality violating semileptonic $b \to u$ operators. The Large Energy limit for the light meson is also considered for both modes. The new effective couplings are constrained using the available data, and several observables in $\bar B \to \rho(\pi\pi) \ell^- \bar \nu_\ell$ in which NP effects can be better identified are selected, using the angular coefficient functions. The complementary role of $\bar B \to \rho(\pi \pi) \ell^- \bar \nu_\ell$ and $\bar B \to a_1 (\rho \pi) \ell^- \bar \nu_\ell$ is discussed., Comment: LaTeX, 39 pages, 21 figures. Discussion of the $a_1$ mode extended. References added
Published: 2019
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31. Identification of particles with Lorentz factor up to $10^{4}$ with Transition Radiation Detectors based on micro-strip silicon detectors

Author: Alozy, J., Belyaev, N., Campbell, M., Cherry, M., Dachs, F., Doronin, S., Filippov, K., Fusco, P., Gargano, F., Heijne, E., Konovalov, S., Krasnopevtsev, D., Llopart, X., Loparco, F., Mascagna, V., Mazziotta, M. N., Pernegger, H., Ponomarenko, D., Prest, M., Pyatiizbyantseva, D., Radomskii, R., Rembser, C., Romaniouk, A., Savchenko, A. A., Schaefer, D., Schioppa, E. J., Shchukin, D., Sergeeva, D. Yu, Shulga, E., Smirnov, S., Smirnov, Y., Soldani, M., Spinelli, P., Strikhanov, M., Teterin, P., Tikhomirov, V., Tishchenko, A. A., Vallazza, E., van Beuzekom, M., van der Heijden, B., Vorobev, K., and Zhukov, K.
Subjects: Physics - Instrumentation and Detectors
Abstract: This work is dedicated to the study of a technique for hadron identification in the TeV momentum range, based on the simultaneous measurement of the energies and of the emission angles of the Transition Radiation (TR) X-rays with respect to the radiating particles. A detector setup has been built and tested with particles in a wide range of Lorentz factors (from about $10^3$ to about $4 \times 10^4$ crossing different types of radiators. The measured double-differential (in energy and angle) spectra of the TR photons are in a reasonably good agreement with TR simulation predictions., Comment: 31 pages, 12 figures, paper published on Nuclear Instruments & Methods A
Published: 2019
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32. MAGIC and Fermi-LAT gamma-ray results on unassociated HAWC sources

Author: Ahnen, M. L., Ansoldi, S., Antonelli, L. A., Arcaro, C., Baack, D., Babić, A., Banerjee, B., Bangale, P., de Almeida, U. Barres, Barrio, J. A., González, J. Becerra, Bednarek, W., Bernardini, E., Berse, R. Ch., Berti, A., Bhattacharyya, W., Biland, A., Blanch, O., Bonnoli, G., Carosi, R., Carosi, A., Ceribella, G., Chatterjee, A., Colak, S. M., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Cumani, P., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., Delfino, M., Delgado, J., Di Pierro, F., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Einecke, S., Elsaesser, D., Ramazani, V. Fallah, Fernández-Barral, A., Fidalgo, D., Fonseca, M. V., Font, L., Fruck, C., Galindo, D., López, R. J. García, Garczarczyk, M., Gaug, M., Giammaria, P., Godinović, N., Gora, D., Guberman, D., Hadasch, D., Hahn, A., Hassan, T., Hayashida, M., Herrera, J., Hose, J., Hrupec, D., Ishio, K., Konno, Y., Kubo, H., Kushida, J., Kuveždić, D., Lelas, D., Lindfors, E., Lombardi, S., Longo, F., López, M., Maggio, C., Majumdar, P., Makariev, M., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Masuda, S., Mazin, D., Mielke, K., Minev, M., Miranda, J. M., Mirzoyan, R., Moralejo, A., Moreno, V., Moretti, E., Nagayoshi, T., Neustroev, V., Niedzwiecki, A., Rosillo, M. Nievas, Nigro, C., Nilsson, K., Ninci, D., Nishijima, K., Noda, K., Nogués, L., Paiano, S., Palacio, J., Paneque, D., Paoletti, R., Paredes, J. M., Pedaletti, G., Peresano, M., Persic, M., Moroni, P. G. Prada, Prandini, E., Puljak, I., Garcia, J. R., Reichardt, I., Rhode, W., Ribó, M., Rico, J., Righi, C., Rugliancich, A., Saito, T., Satalecka, K., Schweizer, T., Sitarek, J., Šnidarić, I., Sobczynska, D., Stamerra, A., Strzys, M., Surić, T., Takahashi, M., Takalo, L., Tavecchio, F., Temnikov, P., Terzić, T., Teshima, M., Torres-Albà, N., Treves, A., Tsujimoto, S., Vanzo, G., Acosta, M. Vazquez, Vovk, I., Ward, J. E., Will, M., Zarić, D., Albert, A., Alfaro, R., Alvarez, C., Arceo, R., Arteaga-Velázquez, J. C., Rojas, D. Avila, Solares, H. A. Ayala, Becerril, A., Belmont-Moreno, E., BenZvi, S. Y., Bernal, A., Braun, J., Caballero-Mora, K. S., Capistrán, T., Carramiñana, A., Casanova, S., Castillo, M., Cotti, U., Cotzomi, J., de León, S. Coutiño, De León, C., De la Fuente, E., Hernandez, R. Diaz, Dichiara, S., Dingus, B. L., DuVernois, M. A., Díaz-Vélez, J. C., Ellsworth, R. W., Engel, K., Enriquez-Rivera, O., Fiorino, D. W., Fleischhack, H., Fraija, N., García-González, J. A., Garfias, F., González-Muñoz, A., González, M. M., Goodman, J. A., Hampel-Arias, Z., Harding, J. P., Hernandez, S., Hueyotl-Zahuantitla, F., Hui, C. M., Hüntemeyer, P., Iriarte, A., Jardin-Blicq, A., Joshi, V., Kaufmann, S., Lara, A., Lauer, R. J., Lee, W. H., Lennarz, D., Vargas, H. León, Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Luna-García, R., López-Coto, R., Malone, K., Marinelli, S. S., Martinez, O., Martinez-Castellanos, I., Martínez-Castro, J., Martínez-Huerta, H., Matthews, J. A., Miranda-Romagnoli, P., Moreno, E., Mostafá, M., Nayerhoda, A., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Pelayo, R., Pretz, J., Pérez-Pérez, E. G., Ren, Z., Rho, C. D., Rivière, C., Rosa-González, D., Rosenberg, M., Ruiz-Velasco, E., Greus, F. Salesa, Sandoval, A., Schneider, M., Arroyo, M. Seglar, Sinnis, G., Smith, A. J., Springer, R. W., Surajbali, P., Taboada, I., Tibolla, O., Tollefson, K., Torres, I., Ukwatta, T. N., Vianello, G., Villaseñor, L., Werner, F., Westerhoff, S., Wood, J., Yapici, T., Yodh, G., Zepeda, A., Zhou, H., Álvarez, J. D., Ajello, M., Baldini, L., Barbiellini, G., Berenji, B., Bissaldi, E., Blandford, R. D., Bonino, R., Bottacini, E., Brandt, T. J., Bregeon, J., Bruel, P., Cameron, R. A., Caputo, R., Caraveo, P. A., Castro, D., Cavazzuti, E., Chiaro, G., Ciprini, S., Costantin, D., D'Ammando, F., de Palma, F., Desai, A., Di Lalla, N., Di Mauro, M., Di Venere, L., Favuzzi, C., Fukazawa, Y., Funk, S., Fusco, P., Gargano, F., Gasparrini, D., Giglietto, N., Giordano, F., Giroletti, M., Glanzman, T., Green, D., Grenier, I. A., Guiriec, S., Harding, A. K., Hays, E., Hewitt, J. W., Horan, D., Jóhannesson, G., Kuss, M., Larsson, S., Liodakis, I., Loparco, F., Lubrano, P., Magill, J. D., Maldera, S., Manfreda, A., Mazziotta, M. N., Mereu, I., Michelson, P. F., Mizuno, T., Monzani, M. E., Morselli, A., Moskalenko, I. V., Negro, M., Nuss, E., Omodei, N., Orienti, M., Orlando, E., Ormes, J. F., Palatiello, M., Paliya, V. S., Pesce-Rollins, M., Petrosian, V., Piron, F., Porter, T. A., Principe, G., Rainò, S., Rani, B., Razzano, M., Razzaque, S., Reimer, A., Reimer, O., Sgrò, C., Siskind, E. J., Spandre, G., Spinelli, P., Tajima, H., Thayer, J. B., Thompson, D. J., Torres, D. F., Torresi, E., Troja, E., Valverde, J., Wood, K., and Yassine, M.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The HAWC Collaboration released the 2HWC catalog of TeV sources, in which 19 show no association with any known high-energy (HE; E > 10 GeV) or very-high-energy (VHE; E > 300 GeV) sources. This catalog motivated follow-up studies by both the MAGIC and Fermi-LAT observatories with the aim of investigating gamma-ray emission over a broad energy band. In this paper, we report the results from the first joint work between HAWC, MAGIC and Fermi-LAT on three unassociated HAWC sources: 2HWC J2006+341, 2HWC J1907+084* and 2HWC J1852+013*. Although no significant detection was found in the HE and VHE regimes, this investigation shows that a minimum 1 degree extension (at 95% confidence level) and harder spectrum in the GeV than the one extrapolated from HAWC results are required in the case of 2HWC J1852+013*, while a simply minimum extension of 0.16 degrees (at 95% confidence level) can already explain the scenario proposed by HAWC for the remaining sources. Moreover, the hypothesis that these sources are pulsar wind nebulae is also investigated in detail., Comment: 12 pages, 3 figures. Accepted for publication in MNRAS
Published: 2019
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33. Status of the plastic scintillator detector for the HERD experiment

Author: Alemanno, F., Altomare, C., Barbato, F.C.T., Bernardini, P., Bissaldi, E., Casilli, E., Cattaneo, P.W., De Mitri, I., de Palma, F., De Vecchi, C., Di Giovanni, A., Di Santo, M., Di Venere, L., Fusco, P., Gargano, F., Guerrisi, C., Kyratzis, D., Licciulli, F., Loparco, F., Marsella, G., Mazziotta, M.N., Pantaleo, F.R., Parenti, A., Pillera, R., Pullia, M., Rappoldi, A., Raselli, G., Rossella, M., Serini, D., Silveri, L., Suma, A., and Surdo, A.
Published: 2023
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34. Unresolved Gamma-Ray Sky through its Angular Power Spectrum

Author: Ackermann, M., Ajello, M., Baldini, L., Ballet, J., Barbiellini, G., Bastieri, D., Bellazzini, R., Bissaldi, E., Blandford, R. D., Bonino, R., Bottacini, E., Bregeon, J., Bruel, P., Buehler, R., Burns, E., Buson, S., Cameron, R. A., Caputo, R., Caraveo, P. A., Cavazzuti, E., Chen, S., Chiaro, G., Ciprini, S., Costantin, D., Cuoco, A., Cutini, S., D'Ammando, F., Luque, P. de la Torre, de Palma, F., Desai, A., Digel, S. W., Di Lalla, N., Di Mauro, M., Di Venere, L., Dirirsa, F. Fana, Favuzzi, C., Franckowiak, A., Fukazawa, Y., Funk, S., Fusco, P., Gargano, F., Gasparrini, D., Giglietto, N., Giordano, F., Giroletti, M., Green, D., Grenier, I. A., Guillemot, L., Guiriec, S., Horan, D., Johannesson, G., Kuss, M., Larsson, S., Latronico, L., Li, J., Liodakis, I., Longo, F., Loparco, F., Lubrano, P., Magill, J. D., Maldera, S., Malyshev, D., Manfreda, A., Mazziotta, M. N., Mereu, I., Michelson, P. F., Mitthumsiri, W., Mizuno, T., Monzani, M. E., Morselli, A., Moskalenko, I. V., Negro, M., Nuss, E., Orienti, M., Orlando, E., Palatiello, M., Paliya, V. S., Paneque, D., Persic, M., Pesce-Rollins, M., Petrosian, V., Piron, F., Porter, T. A., Principe, G., Raino, S., Rando, R., Razzano, M., Razzaque, S., Reimer, A., Reimer, O., Serini, D., Sgro, C., Siskind, E. J., Spandre, G., Spinelli, P., Suson, D. J., Tajima, H., Takahashi, M., Thayer, J. B., Tibaldo, L., Torres, D. F., Troja, E., Venters, T. M., Vianello, G., Wood, K., Yassine, M., Zaharijas, G., Ammazzalorso, S., Fornengo, N., and Regis, M.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Nongalactic Astrophysics, High Energy Physics - Phenomenology
Abstract: The gamma-ray sky has been observed with unprecedented accuracy in the last decade by the Fermi large area telescope (LAT), allowing us to resolve and understand the high-energy Universe. The nature of the remaining unresolved emission (unresolved gamma-ray background, UGRB) below the LAT source detection threshold can be uncovered by characterizing the amplitude and angular scale of the UGRB fluctuation field. This work presents a measurement of the UGRB autocorrelation angular power spectrum based on eight years of Fermi LAT Pass 8 data products. The analysis is designed to be robust against contamination from resolved sources and noise systematics. The sensitivity to subthreshold sources is greatly enhanced with respect to previous measurements. We find evidence (with $\sim$3.7$\sigma$ significance) that the scenario in which two classes of sources contribute to the UGRB signal is favored over a single class. A double power law with exponential cutoff can explain the anisotropy energy spectrum well, with photon indices of the two populations being 2.55 $\pm$ 0.23 and 1.86 $\pm$ 0.15., Comment: 8 + 12 (SOM) pages, Contact author: Michela Negro (michela.negro@to.infn.it). (Typos in Tab. VII in previous versions)
Published: 2018
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35. Configurational Entropy can disentangle conventional hadrons from exotica

Author: Colangelo, P. and Loparco, F.
Subjects: High Energy Physics - Phenomenology
Abstract: We evaluate the Configurational Entropy (CE) for scalar mesons and for $J^P=\frac{1}{2}^+$ baryons in a holographic approach, varying the dimension of boundary theory operators and using the soft-wall dual model of QCD. We find that hybrid and multiquark mesons are characterized by an increasingly large CE. A similar behavior is observed for $J^P=\frac{1}{2}^+$ baryons, where the CE of pentaquarks is larger than for three-quark baryons, for same radial number. Configurational Entropy seems relevant in disentangling conventional hadrons from exotica., Comment: 13 pages, 4 figures
Published: 2018
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36. A compact, light scintillating fiber tracker with SiPM readout

Author: Pillera, R., Altomare, C., Bissaldi, E., De Gaetano, S., De Robertis, G., Dipinto, P., Di Venere, L., Franco, M., Fusco, P., Gargano, F., Giordano, F., Lacalamita, N., Licciulli, F., Loparco, F., Loporchio, S., Lorusso, L., Maiorano, F., Martiradonna, S., Mazziotta, M.N., Mongelli, M., Pantaleo, F.R., Panzarini, G., Papagni, M.G., Pastore, C., Rizzi, M., Serini, D., and Triggiani, R.
Published: 2023
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37. VERITAS and Fermi-LAT observations of new HAWC sources

Author: VERITAS Collaboration, Abeysekara, A. U., Archer, A., Benbow, W., Bird, R., Brose, R., Buchovecky, M., Buckley, J. H., Bugaev, V., Chromey, A. J., Connolly, M. P., Cui, W., Daniel, M. K., Falcone, A., Feng, Q., Finley, J. P., Fortson, L., Furniss, A., Hutten, M., Hanna, D., Hervet, O., Holder, J., Hughes, G., Humensky, T. B., Johnson, C. A., Kaaret, P., Kar, P., Kertzman, M., Kieda, D., Krause, M., Krennrich, F., Kumar, S., Lang, M. J., Lin, T. T. Y., McArthur, S., Moriarty, P., Mukherjee, R., O'Brien, S., Ong, R. A., Otte, A. N., Park, N., Petrashyk, A., Pohl, M., Pueschel, E., Quinn, J., Ragan, K., Reynolds, P. T., Richards, G. T., Roache, E., Rulten, C., Sadeh, I., Santander, M., Sembroski, G. H., Shahinyan, K., Sushch, I., Tyler, J., Wakely, S. P., Weinstein, A., Wells, R. M., Wilcox, P., Wilhelm, A., Williams, D. A., Williamson, T. J., Zitzer, B., Collaboration, Fermi-LAT, Abdollahi, S., Ajello, M., Baldini, L., Barbiellini, G., Bastieri, D., Bellazzini, R., Berenji, B., Bissaldi, E., Blandford, R. D., Bonino, R., Bottacini, E., Brandt, T. J., Bruel, P., Buehler, R., Cameron, R. A., Caputo, R., Caraveo, P. A., Castro, D., Cavazzuti, E., Charles, E., Chiaro, G., Ciprini, S., Cohen-Tanugi, J., Costantin, D., Cutini, S., D'Ammando, F., de Palma, F., Di Lalla, N., Di Mauro, M., Di Venere, L., Dominguez, A., Favuzzi, C., Fegan, S. J., Franckowiak, A., Fukazawa, Y., Funk, S., Fusco, P., Gargano, F., Gasparrini, D., Giglietto, N., Giordano, F., Giroletti, M., Green, D., Grenier, I. A., Guillemot, L., Guiriec, S., Hays, E., Hewitt, J. W., Horan, D., Johannesson, G., Kensei, S., Kuss, M., Larsson, S., Latronico, L., Lemoine-Goumard, M., Li, J., Longo, F., Loparco, F., Lovellette, M. N., Lubrano, P., Magill, J. D., Maldera, S., Mazziotta, M. N., McEnery, J. E., Michelson, P. F., Mitthumsiri, W., Mizuno, T., Monzani, M. E., Morselli, A., Moskalenko, I. V., Negro, M., Nuss, E., Ojha, R., Omodei, N., Orienti, M., Orlando, E., Palatiello, M., Paliya, V. S., Paneque, D., Perkins, J. S., Persic, M., Pesce-Rollins, M., Petrosian, V., Piron, F., Porter, T. A., Principe, G., Raino, S., Rando, R., Rani, B., Razzano, M., Razzaque, S., Reimer, A., Reimer, O., Reposeur, T., Sgro, C., Siskind, E. J., Spandre, G., Spinelli, P., Suson, D. J., Tajima, H., Thayer, J. B., Thompson, D. J., Torres, D. F., Tosti, G., Troja, E., Valverde, J., Vianello, G., Vogel, M., Wood, K., Yassine, M., Collaboration, HAWC, Alfaro, R., Alvarez, C., Alvarez, J. D., Arceo, R., Arteaga-Velazquez, J. C., Rojas, D. Avila, Solares, H. A. Ayala, Becerril, A., Belmont-Moreno, E., BenZvi, S. Y., Bernal, A., Braun, J., Brisbois, C., Caballero-Mora, K. S., Capistran, T., Carraminana, A., Casanova, S., Castillo, M., Cotti, U., Cotzomi, J., de Leon, S. Coutino, De Leon, C., De la Fuente, E., Dichiara, S., Dingus, B. L., DuVernois, M. A., Diaz-Velez, J. C., Engel, K., Enriquez-Rivera, O., Fiorino, D. W., Fleischhack, H., Fraija, N., Garcia-Gonzalez, J. A., Garfias, F., Munoz, A. Gonzalez, Gonzalez, M. M., Goodman, J. A., Hampel-Arias, Z., Harding, J. P., Hernandez, S., Hernandez-Almada, A., Hona, B., Hueyotl-Zahuantitla, F., Hui, C. M., Huntemeyer, P., Iriarte, A., Jardin-Blicq, A., Joshi, V., Kaufmann, S., Lara, A., Lauer, R. J., Lee, W. H., Lennarz, D., Vargas, H. Leon, Linnemann, J. T., Longinotti, A. L., Luis-Raya, G., Luna-Garcia, R., Lopez-Coto, R., Malone, K., Marinelli, S. S., Martinez, O., Martinez-Castellanos, I., Martinez-Castro, J., Martinez-Huerta, H., Matthews, J. A., Miranda-Romagnoli, P., Moreno, E., Mostafa, M., Nayerhoda, A., Nellen, L., Newbold, M., Nisa, M. U., Noriega-Papaqui, R., Pelayo, R., Pretz, J., Perez-Perez, E. G., Ren, Z., Rho, C. D., Riviere, C., Rosa-Gonzalez, D., Rosenberg, M., Ruiz-Velasco, E., Salazar, H., Greus, F. Salesa, Sandoval, A., Schneider, M., Arroyo, M. Seglar, Sinnis, G., Smith, A. J., Springer, R. W., Surajbali, P., Taboada, I., Tibolla, O., Tollefson, K., Torres, I., Ukwatta, T. N., Villasenor, L., Weisgarber, T., Westerhoff, S., Wisher, I. G., Wood, J., Yapici, T., Yodh, G., Zepeda, A., and Zhou, H.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The HAWC (High Altitude Water Cherenkov) collaboration recently published their 2HWC catalog, listing 39 very high energy (VHE; >100~GeV) gamma-ray sources based on 507 days of observation. Among these, there are nineteen sources that are not associated with previously known TeV sources. We have studied fourteen of these sources without known counterparts with VERITAS and Fermi-LAT. VERITAS detected weak gamma-ray emission in the 1~TeV-30~TeV band in the region of DA 495, a pulsar wind nebula coinciding with 2HWC J1953+294, confirming the discovery of the source by HAWC. We did not find any counterpart for the selected fourteen new HAWC sources from our analysis of Fermi-LAT data for energies higher than 10 GeV. During the search, we detected GeV gamma-ray emission coincident with a known TeV pulsar wind nebula, SNR G54.1+0.3 (VER J1930+188), and a 2HWC source, 2HWC J1930+188. The fluxes for isolated, steady sources in the 2HWC catalog are generally in good agreement with those measured by imaging atmospheric Cherenkov telescopes. However, the VERITAS fluxes for SNR G54.1+0.3, DA 495, and TeV J2032+4130 are lower than those measured by HAWC and several new HAWC sources are not detected by VERITAS. This is likely due to a change in spectral shape, source extension, or the influence of diffuse emission in the source region., Comment: Accepted for publication in the ApJ, Corresponding author: Nahee Park (VERITAS Collaboration), John W. Hewitt (Fermi-LAT Collaboration), Ignacio Taboada (HAWC Collaboration), 30 pages, 12 figures
Published: 2018
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38. In-flight performance of the DAMPE silicon tracker

Author: Tykhonov, A., Ambrosi, G., Asfandiyarov, R., Azzarello, P., Bernardini, P., Bertucci, B., Bolognini, A., Cadoux, F., D'Amone, A., De Benedittis, A., De Mitri, I., Di Santo, M., Dong, Y. F., Duranti, M., D'Urso, D., Fan, R. R., Fusco, P., Gallo, V., Gao, M., Gargano, F., Garrappa, S., Gong, K., Ionica, M., La Marra, D., Loparco, F., Marsella, G., Mazziotta, M. N., Peng, W. X., Qiao, R., Salinas, M. M., Surdo, A., Vagelli, V., Vitillo, S., Wang, H. Y., Wang, J. Z., Wang, Z. M., Wu, D., Wu, X., Zhang, F., Zhang, J. Y., Zhao, H., and Zimmer, S.
Subjects: Astrophysics - Instrumentation and Methods for Astrophysics, Physics - Instrumentation and Detectors
Abstract: DAMPE (DArk Matter Particle Explorer) is a spaceborne high-energy cosmic ray and gamma-ray detector, successfully launched in December 2015. It is designed to probe astroparticle physics in the broad energy range from few GeV to 100 TeV. The scientific goals of DAMPE include the identification of possible signatures of Dark Matter annihilation or decay, the study of the origin and propagation mechanisms of cosmic-ray particles, and gamma-ray astronomy. DAMPE consists of four sub-detectors: a plastic scintillator strip detector, a Silicon-Tungsten tracKer-converter (STK), a BGO calorimeter and a neutron detector. The STK is composed of six double layers of single-sided silicon micro-strip detectors interleaved with three layers of tungsten for photon conversions into electron-positron pairs. The STK is a crucial component of DAMPE, allowing to determine the direction of incoming photons, to reconstruct tracks of cosmic rays and to estimate their absolute charge (Z). We present the in-flight performance of the STK based on two years of in-flight DAMPE data, which includes the noise behavior, signal response, thermal and mechanical stability, alignment and position resolution.
Published: 2018
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39. Search for Features in the Cosmic-Ray Electron and Positron spectrum measured by the Fermi Large Area Telescope

Author: Mazziotta, M. N., Costanza, F., Cuoco, A., Gargano, F., Loparco, F., and Zimmer, S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: The Large Area Telescope onboard the Fermi Gamma-ray Space Telescope has collected the largest ever sample of high-energy cosmic-ray electron and positron events. Possible features in their energy spectrum could be a signature of the presence of nearby astrophysical sources, or of more exotic sources, such as annihilation or decay of dark matter (DM) particles in the Galaxy. In this paper for the first time we search for a delta-like line feature in the cosmic-ray electron and positron spectrum. We also search for a possible feature originating from DM particles annihilating into electron-positron pairs. Both searches yield negative results, but we are able to set constraints on the line intensity and on the velocity-averaged DM annihilation cross section. Our limits extend up to DM masses of 1.7 $TeV/c^2$, and exclude the thermal value of the annihilation cross-section for DM lighter than 150 $GeV/c^2$., Comment: Matches the version accepted by PRD; the limit has been extended up to 1.7 TeV overlapping most of the region covered by DAMPE and CALET ; 10 pages and 9 figures
Published: 2017
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40. Internal alignment and position resolution of the silicon tracker of DAMPE determined with orbit data

Author: Tykhonov, A., Ambrosi, G., Asfandiyarov, R., Azzarello, P., Bernardini, P., Bertucci, B., Bolognini, A., Cadoux, F., D'Amone, A., De Benedittis, A., De Mitri, I., Di Santo, M., Dong, Y. F., Duranti, M., D'Urso, D., Fan, R. R., Fusco, P., Gallo, V., Gao, M., Gargano, F., Garrappa, S., Gong, K., Ionica, M., La Marra, D., Lei, S. J., Li, X., Loparco, F., Marsella, G., Mazziotta, M. N., Peng, W. X., Qiao, R., Salinas, M. M., Surdo, A., Vagelli, V., Vitillo, S., Wang, H. Y., Wang, J. Z., Wu, D., Wu, X., Zhang, F., Zhang, J. Y., Zhao, H., and Zimmer, S.
Subjects: Physics - Instrumentation and Detectors
Abstract: The DArk Matter Particle Explorer (DAMPE) is a space-borne particle detector designed to probe electrons and gamma-rays in the few GeV to 10 TeV energy range, as well as cosmic-ray proton and nuclei components between 10 GeV and 100 TeV. The silicon-tungsten tracker-converter is a crucial component of DAMPE. It allows the direction of incoming photons converting into electron-positron pairs to be estimated, and the trajectory and charge (Z) of cosmic-ray particles to be identified. It consists of 768 silicon micro-strip sensors assembled in 6 double layers with a total active area of 6.6 m$^2$. Silicon planes are interleaved with three layers of tungsten plates, resulting in about one radiation length of material in the tracker. Internal alignment parameters of the tracker have been determined on orbit, with non-showering protons and helium nuclei. We describe the alignment procedure and present the position resolution and alignment stability measurements.
Published: 2017
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41. Direct detection of a break in the teraelectronvolt cosmic-ray spectrum of electrons and positrons

Author: Ambrosi, G., An, Q., Asfandiyarov, R., Azzarello, P., Bernardini, P., Bertucci, B., Cai, M. S., Chang, J., Chen, D. Y., Chen, H. F., Chen, J. L., Chen, W., Cui, M. Y., Cui, T. S., D'Amone, A., De Benedittis, A., De Mitri, I., Di Santo, M., Dong, J. N., Dong, T. K., Dong, Y. F., Dong, Z. X., Donvito, G., Droz, D., Duan, K. K., Duan, J. L., Duranti, M., D'Urso, D., Fan, R. R., Fan, Y. Z., Fang, F., Feng, C. Q., Feng, L., Fusco, P., Gallo, V., Gan, F. J., Gao, M., Gao, S. S., Gargano, F., Garrappa, S., Gong, K., Gong, Y. Z., Guo, D. Y., Guo, J. H., Hu, Y. M., Huang, G. S., Huang, Y. Y., Ionica, M., Jiang, D., Jiang, W., Jin, X., Kong, J., Lei, S. J., Li, S., Li, X., Li, W. L., Li, Y., Liang, Y. F., Liang, Y. M., Liao, N. H., Liu, H., Liu, J., Liu, S. B., Liu, W. Q., Liu, Y., Loparco, F., Ma, M., Ma, P. X., Ma, S. Y., Ma, T., Ma, X. Q., Ma, X. Y., Marsella, G., Mazziotta, M. N., Mo, D., Niu, X. Y., Peng, X. Y., Peng, W. X., Qiao, R., Rao, J. N., Salinas, M. M., Shang, G. Z., Shen, W. H., Shen, Z. Q., Shen, Z. T., Song, J. X., Su, H., Su, M., Sun, Z. Y., Surdo, A., Teng, X. J., Tian, X. B., Tykhonov, A., Vagelli, V., Vitillo, S., Wang, C., Wang, H., Wang, H. Y., Wang, J. Z., Wang, L. G., Wang, Q., Wang, S., Wang, X. H., Wang, X. L., Wang, Y. F., Wang, Y. P., Wang, Y. Z., Wen, S. C., Wang, Z. M., Wei, D. M., Wei, J. J., Wei, Y. F., Wu, D., Wu, J., Wu, L. B., Wu, S. S., Wu, X., Xi, K., Xia, Z. Q., Xin, Y. L., Xu, H. T., Xu, Z. L., Xu, Z. Z., Xue, G. F., Yang, H. B., Yang, P., Yang, Y. Q., Yang, Z. L., Yao, H. J., Yu, Y. H., Yuan, Q., Yue, C., Zang, J. J., Zhang, C., Zhang, D. L., Zhang, F., Zhang, J. B., Zhang, J. Y., Zhang, J. Z., Zhang, L., Zhang, P. F., Zhang, S. X., Zhang, W. Z., Zhang, Y., Zhang, Y. J., Zhang, Y. Q., Zhang, Y. L., Zhang, Y. P., Zhang, Z., Zhang, Z. Y., Zhao, H., Zhao, H. Y., Zhao, X. F., Zhou, C. Y., Zhou, Y., Zhu, X., Zhu, Y., and Zimmer, S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment, High Energy Physics - Phenomenology
Abstract: High energy cosmic ray electrons plus positrons (CREs), which lose energy quickly during their propagation, provide an ideal probe of Galactic high-energy processes and may enable the observation of phenomena such as dark-matter particle annihilation or decay. The CRE spectrum has been directly measured up to $\sim 2$ TeV in previous balloon- or space-borne experiments, and indirectly up to $\sim 5$ TeV by ground-based Cherenkov $\gamma$-ray telescope arrays. Evidence for a spectral break in the TeV energy range has been provided by indirect measurements of H.E.S.S., although the results were qualified by sizeable systematic uncertainties. Here we report a direct measurement of CREs in the energy range $25~{\rm GeV}-4.6~{\rm TeV}$ by the DArk Matter Particle Explorer (DAMPE) with unprecedentedly high energy resolution and low background. The majority of the spectrum can be properly fitted by a smoothly broken power-law model rather than a single power-law model. The direct detection of a spectral break at $E \sim0.9$ TeV confirms the evidence found by H.E.S.S., clarifies the behavior of the CRE spectrum at energies above 1 TeV and sheds light on the physical origin of the sub-TeV CREs., Comment: 18 pages, 6 figures, Nature in press, doi:10.1038/nature24475
Published: 2017
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42. Science with e-ASTROGAM (A space mission for MeV-GeV gamma-ray astrophysics)

Author: De Angelis, A., Tatischeff, V., Grenier, I. A., McEnery, J., Mallamaci, M., Tavani, M., Oberlack, U., Hanlon, L., Walter, R., Argan, A., Von Ballmoos, P., Bulgarelli, A., Bykov, A., Hernanz, M., Kanbach, G., Kuvvetli, I., Pearce, M., Zdziarski, A., Conrad, J., Ghisellini, G., Harding, A., Isern, J., Leising, M., Longo, F., Madejski, G., Martinez, M., Mazziotta, M. N., Paredes, J. M., Pohl, M., Rando, R., Razzano, M., Aboudan, A., Ackermann, M., Addazi, A., Ajello, M., Albertus, C., Alvarez, J. M., Ambrosi, G., Anton, S., Antonelli, L. A., Babic, A., Baibussinov, B., Balbo, M., Baldini, L., Balman, S., Bambi, C., de Almeida, U. Barres, Barrio, J. A., Bartels, R., Bastieri, D., Bednarek, W., Bernard, D., Bernardini, E., Bernasconi, T., Bertucci, B., Biland, A., Bissaldi, E., Boettcher, M., Bonvicini, V., Ramon, V. Bosch, Bottacini, E., Bozhilov, V., Bretz, T., Branchesi, M., Brdar, V., Bringmann, T., Brogna, A., Jorgensen, C. Budtz, Busetto, G., Buson, S., Busso, M., Caccianiga, A., Camera, S., Campana, R., Caraveo, P., Cardillo, M., Carlson, P., Celestin, S., Cermeno, M., Chen, A., Cheung, C. C, Churazov, E., Ciprini, S., Coc, A., Colafrancesco, S., Coleiro, A., Collmar, W., Coppi, P., da Silva, R. Curado, Cutini, S., DAmmando, F., De Lotto, B., de Martino, D., De Rosa, A., Del Santo, M., Delgado, L., Diehl, R., Dietrich, S., Dolgov, A. D., Dominguez, A., Prester, D. Dominis, Donnarumma, I., Dorner, D., Doro, M., Dutra, M., Elsaesser, D., Fabrizio, M., FernandezBarral, A., Fioretti, V., Foffano, L., Formato, V., Fornengo, N., Foschini, L., Franceschini, A., Franckowiak, A., Funk, S., Fuschino, F., Gaggero, D., Galanti, G., Gargano, F., Gasparrini, D., Gehrz, R., Giammaria, P., Giglietto, N., Giommi, P., Giordano, F., Giroletti, M., Ghirlanda, G., Godinovic, N., Gouiffes, C., Grove, J. E., Hamadache, C., Hartmann, D. H., Hayashida, M., Hryczuk, A., Jean, P., Johnson, T., Jose, J., Kaufmann, S., Khelifi, B., Kiener, J., Knodlseder, J., Kole, M., Kopp, J., Kozhuharov, V., Labanti, C., Lalkovski, S., Laurent, P., Limousin, O., Linares, M., Lindfors, E., Lindner, M., Liu, J., Lombardi, S., Loparco, F., LopezCoto, R., Moya, M. Lopez, Lott, B., Lubrano, P., Malyshev, D., Mankuzhiyil, N., Mannheim, K., Marcha, M. J., Marciano, A., Marcote, B., Mariotti, M., Marisaldi, M., McBreen, S., Mereghetti, S., Merle, A., Mignani, R., Minervini, G., Moiseev, A., Morselli, A., Moura, F., Nakazawa, K., Nava, L., Nieto, D., Orienti, M., Orio, M., Orlando, E., Orleanski, P., Paiano, S., Paoletti, R., Papitto, A., Pasquato, M., Patricelli, B., PerezGarcia, M. A., Persic, M., Piano, G., Pichel, A., Pimenta, M., Pittori, C., Porter, T., Poutanen, J., Prandini, E., Prantzos, N., Produit, N., Profumo, S., Queiroz, F. S., Raino, S., Raklev, A., Regis, M., Reichardt, I., Rephaeli, Y., Rico, J., Rodejohann, W., Fernandez, G. Rodriguez, Roncadelli, M., Roso, L., Rovero, A., Ruffini, R., Sala, G., SanchezConde, M. A., Santangelo, A., Parkinson, P. Saz, Sbarrato, T., Shearer, A., Shellard, R., Short, K., Siegert, T., Siqueira, C., Spinelli, P., Stamerra, A., Starrfield, S., Strong, A., Strumke, I., Tavecchio, F., Taverna, R., Terzic, T., Thompson, D. J., Tibolla, O., Torres, D. F., Turolla, R., Ulyanov, A., Ursi, A., Vacchi, A., Abeele, J. Van den, Kirilovai, G. Vankova, Venter, C., Verrecchia, F., Vincent, P., Wang, X., Weniger, C., Wu, X., Zaharijas, G., Zampieri, L., Zane, S., Zimmer, S., Zoglauer, A., and collaboration, the eASTROGAM
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Solar and Stellar Astrophysics, High Energy Physics - Experiment
Abstract: e-ASTROGAM (enhanced ASTROGAM) is a breakthrough Observatory space mission, with a detector composed by a Silicon tracker, a calorimeter, and an anticoincidence system, dedicated to the study of the non-thermal Universe in the photon energy range from 0.3 MeV to 3 GeV - the lower energy limit can be pushed to energies as low as 150 keV for the tracker, and to 30 keV for calorimetric detection. The mission is based on an advanced space-proven detector technology, with unprecedented sensitivity, angular and energy resolution, combined with polarimetric capability. Thanks to its performance in the MeV-GeV domain, substantially improving its predecessors, e-ASTROGAM will open a new window on the non-thermal Universe, making pioneering observations of the most powerful Galactic and extragalactic sources, elucidating the nature of their relativistic outflows and their effects on the surroundings. With a line sensitivity in the MeV energy range one to two orders of magnitude better than previous generation instruments, e-ASTROGAM will determine the origin of key isotopes fundamental for the understanding of supernova explosion and the chemical evolution of our Galaxy. The mission will provide unique data of significant interest to a broad astronomical community, complementary to powerful observatories such as LIGO-Virgo-GEO600-KAGRA, SKA, ALMA, E-ELT, TMT, LSST, JWST, Athena, CTA, IceCube, KM3NeT, and LISA., Comment: Published on Journal of High Energy Astrophysics (Elsevier)
Published: 2017
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43. Measurement of the cosmic ray proton spectrum from 40 GeV to 100 TeV with the DAMPE satellite.

Author: DAMPE Collaboration, An, Q, Asfandiyarov, R, Azzarello, P, Bernardini, P, Bi, XJ, Cai, MS, Chang, J, Chen, DY, Chen, HF, Chen, JL, Chen, W, Cui, MY, Cui, TS, Dai, HT, D'Amone, A, De Benedittis, A, De Mitri, I, Di Santo, M, Ding, M, Dong, TK, Dong, YF, Dong, ZX, Donvito, G, Droz, D, Duan, JL, Duan, KK, D'Urso, D, Fan, RR, Fan, YZ, Fang, F, Feng, CQ, Feng, L, Fusco, P, Gallo, V, Gan, FJ, Gao, M, Gargano, F, Gong, K, Gong, YZ, Guo, DY, Guo, JH, Guo, XL, Han, SX, Hu, YM, Huang, GS, Huang, XY, Huang, YY, Ionica, M, Jiang, W, Jin, X, Kong, J, Lei, SJ, Li, S, Li, WL, Li, X, Li, XQ, Li, Y, Liang, YF, Liang, YM, Liao, NH, Liu, CM, Liu, H, Liu, J, Liu, SB, Liu, WQ, Liu, Y, Loparco, F, Luo, CN, Ma, M, Ma, PX, Ma, SY, Ma, T, Ma, XY, Marsella, G, Mazziotta, MN, Mo, D, Niu, XY, Pan, X, Peng, WX, Peng, XY, Qiao, R, Rao, JN, Salinas, MM, Shang, GZ, Shen, WH, Shen, ZQ, Shen, ZT, Song, JX, Su, H, Su, M, Sun, ZY, Surdo, A, Teng, XJ, Tykhonov, A, Vitillo, S, Wang, C, Wang, H, Wang, HY, and Wang, JZ
Subjects: DAMPE Collaboration, astro-ph.HE
Abstract: The precise measurement of the spectrum of protons, the most abundant component of the cosmic radiation, is necessary to understand the source and acceleration of cosmic rays in the Milky Way. This work reports the measurement of the cosmic ray proton fluxes with kinetic energies from 40 GeV to 100 TeV, with 2 1/2 years of data recorded by the DArk Matter Particle Explorer (DAMPE). This is the first time that an experiment directly measures the cosmic ray protons up to ~100 TeV with high statistics. The measured spectrum confirms the spectral hardening at ~300 GeV found by previous experiments and reveals a softening at ~13.6 TeV, with the spectral index changing from ~2.60 to ~2.85. Our result suggests the existence of a new spectral feature of cosmic rays at energies lower than the so-called knee and sheds new light on the origin of Galactic cosmic rays.
Published: 2019

44. Measurement of the cosmic ray proton spectrum from 40 GeV to 100 TeV with the DAMPE satellite

Author: Collaboration, DAMPE, An, Q, Asfandiyarov, R, Azzarello, P, Bernardini, P, Bi, XJ, Cai, MS, Chang, J, Chen, DY, Chen, HF, Chen, JL, Chen, W, Cui, MY, Cui, TS, Dai, HT, D’Amone, A, De Benedittis, A, De Mitri, I, Di Santo, M, Ding, M, Dong, TK, Dong, YF, Dong, ZX, Donvito, G, Droz, D, Duan, JL, Duan, KK, D’Urso, D, Fan, RR, Fan, YZ, Fang, F, Feng, CQ, Feng, L, Fusco, P, Gallo, V, Gan, FJ, Gao, M, Gargano, F, Gong, K, Gong, YZ, Guo, DY, Guo, JH, Guo, XL, Han, SX, Hu, YM, Huang, GS, Huang, XY, Huang, YY, Ionica, M, Jiang, W, Jin, X, Kong, J, Lei, SJ, Li, S, Li, WL, Li, X, Li, XQ, Li, Y, Liang, YF, Liang, YM, Liao, NH, Liu, CM, Liu, H, Liu, J, Liu, SB, Liu, WQ, Liu, Y, Loparco, F, Luo, CN, Ma, M, X., P, Y., S, Ma, T, Y., X, Marsella, G, Mazziotta, MN, Mo, D, Niu, XY, Pan, X, Peng, WX, Peng, XY, Qiao, R, Rao, JN, Salinas, MM, Shang, GZ, Shen, WH, Shen, ZQ, Shen, ZT, Song, JX, Su, H, Su, M, Sun, ZY, Surdo, A, Teng, XJ, Tykhonov, A, Vitillo, S, Wang, C, Wang, H, Wang, HY, and Wang, JZ
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, DAMPE Collaboration, astro-ph.HE
Abstract: The precise measurement of the spectrum of protons, the most abundant component of the cosmic radiation, is necessary to understand the source and acceleration of cosmic rays in the Milky Way. This work reports the measurement of the cosmic ray proton fluxes with kinetic energies from 40 GeV to 100 TeV, with 2 1/2 years of data recorded by the DArk Matter Particle Explorer (DAMPE). This is the first time that an experiment directly measures the cosmic ray protons up to ~100 TeV with high statistics. The measured spectrum confirms the spectral hardening at ~300 GeV found by previous experiments and reveals a softening at ~13.6 TeV, with the spectral index changing from ~2.60 to ~2.85. Our result suggests the existence of a new spectral feature of cosmic rays at energies lower than the so-called knee and sheds new light on the origin of Galactic cosmic rays.
Published: 2019

45. A light tracker based on scintillating fibers with SiPM readout

Author: Mazziotta, M.N., Altomare, C., Bissaldi, E., De Gaetano, S., De Robertis, G., Dipinto, P., Di Venere, L., Franco, M., Fusco, P., Gargano, F., Giordano, F., Lacalamita, N., Licciulli, F., Loparco, F., Loporchio, S., Lorusso, L., Maiorano, F., Martiradonna, S., Mongelli, M., Pantaleo, F., Panzarini, G., Papagni, M.G., Pastore, C., Pillera, R., Rizzi, M., Serini, D., and Triggiani, R.
Published: 2022
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46. Erratum to: Inclusive semileptonic Λb decays in the Standard Model and beyond

Author: Colangelo, P., De Fazio, F., and Loparco, F.
Published: 2022
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47. A high efficiency fast-response gamma detector with mrad pointing capabilities

Author: Altomare, C., Di Venere, L., Pantaleo, F.R., Fanchini, E., Giordano, F., Loparco, F., Morichi, M., Spinelli, P., and Swiderski, L.
Published: 2022
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48. The DArk Matter Particle Explorer mission

Author: Chang, J., Ambrosi, G., An, Q., Asfandiyarov, R., Azzarello, P., Bernardini, P., Bertucci, B., Cai, M. S., Caragiulo, M., Chen, D. Y., Chen, H. F., Chen, J. L., Chen, W., Cui, M. Y., Cui, T. S., D'Amone, A., De Benedittis, A., De Mitri, I., Di Santo, M., Dong, J. N., Dong, T. K., Dong, Y. F., Dong, Z. X., Donvito, G., Droz, D., Duan, K. K., Duan, J. L., Duranti, M., D'Urso, D., Fan, R. R., Fan, Y. Z., Fang, F., Feng, C. Q., Feng, L., Fusco, P., Gallo, V., Gan, F. J., Gan, W. Q., Gao, M., Gao, S. S., Gargano, F., Gong, K., Gong, Y. Z., Guo, J. H., Hu, Y. M., Huang, G. S., Huang, Y. Y., Ionica, M., Jiang, D., Jiang, W., Jin, X., Kong, J., Lei, S. J., Li, S., Li, X., Li, W. L., Li, Y., Liang, Y. F., Liang, Y. M., Liao, N. H., Liu, Q. Z., Liu, H., Liu, J., Liu, S. B., Liu, W. Q., Liu, Y., Loparco, F., Lü, J., Ma, M., Ma, P. X., Ma, S. Y., Ma, T., Ma, X. Q., Ma, X. Y., Marsella, G., Mazziotta, M. N., Mo, D., Miao, T. T., Niu, X. Y., Pohl, M., Peng, X. Y., Peng, W. X., Qiao, R., Rao, J. N., Salinas, M. M., Shang, G. Z., Shen, W. H., Shen, Z. Q., Shen, Z. T., Song, J. X., Su, H., Su, M., Sun, Z. Y., Surdo, A., Teng, X. J., Tian, X. B., Tykhonov, A., Vagelli, V., Vitillo, S., Wang, C., Wang, Chi, Wang, H., Wang, H. Y., Wang, J. Z., Wang, L. G., Wang, Q., Wang, S., Wang, X. H., Wang, X. L., Wang, Y. F., Wang, Y. P., Wang, Y. Z., Wen, S. C., Wang, Z. M., Wei, D. M., Wei, J. J., Wei, Y. F., Wu, D., Wu, J., Wu, S. S., Wu, X., Xi, K., Xia, Z. Q., Xin, Y. L., Xu, H. T., Xu, Z. L., Xu, Z. Z., Xue, G. F., Yang, H. B., Yang, J., Yang, P., Yang, Y. Q., Yang, Z. L., Yao, H. J., Yu, Y. H., Yuan, Q., Yue, C., Zang, J. J., Zhang, C., Zhang, D. L., Zhang, F., Zhang, J. B., Zhang, J. Y., Zhang, J. Z., Zhang, L., Zhang, P. F., Zhang, S. X., Zhang, W. Z., Zhang, Y., Zhang, Y. J., Zhang, Y. Q., Zhang, Y. L., Zhang, Y. P., Zhang, Z., Zhang, Z. Y., Zhao, H., Zhao, H. Y., Zhao, X. F., Zhou, C. Y., Zhou, Y., Zhu, X., Zhu, Y., and Zimmer, S.
Subjects: Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract: The DArk Matter Particle Explorer (DAMPE), one of the four scientific space science missions within the framework of the Strategic Pioneer Program on Space Science of the Chinese Academy of Sciences, is a general purpose high energy cosmic-ray and gamma-ray observatory, which was successfully launched on December 17th, 2015 from the Jiuquan Satellite Launch Center. The DAMPE scientific objectives include the study of galactic cosmic rays up to $\sim 10$ TeV and hundreds of TeV for electrons/gammas and nuclei respectively, and the search for dark matter signatures in their spectra. In this paper we illustrate the layout of the DAMPE instrument, and discuss the results of beam tests and calibrations performed on ground. Finally we present the expected performance in space and give an overview of the mission key scientific goals., Comment: 45 pages, including 29 figures and 6 tables. Published in Astropart. Phys
Published: 2017
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49. Cosmic-ray electron+positron spectrum from 7 GeV to 2 TeV with the Fermi Large Area Telescope

Author: Collaboration, Fermi-LAT, Abdollahi, S., Ackermann, M., Ajello, M., Atwood, W. B., Baldini, L., Barbiellini, G., Bastieri, D., Bellazzini, R., Bloom, E. D., Bonino, R., Brandt, T. J., Bregeon, J., Bruel, P., Buehler, R., Cameron, R. A., Caputo, R., Caragiulo, M., Castro, D., Cavazzuti, E., Cecchi, C., Chekhtman, A., Ciprini, S., Cohen-Tanugi, J., Costanza, F., Cuoco, A., Cutini, S., D'Ammando, F., de Palma, F., Desiante, R., Digel, S. W., Di Lalla, N., Di Mauro, M., Di Venere, L., Drell, P. S., Drlica-Wagner, A., Favuzzi, C., Focke, W. B., Funk, S., Fusco, P., Gargano, F., Gasparrini, D., Giglietto, N., Giordano, F., Giroletti, M., Green, D., Guillemot, L., Guiriec, S., Harding, A. K., Jogler, T., Jóhannesson, G., Kamae, T., Kuss, M., La Mura, G., Latronico, L., Longo, F., Loparco, F., Lubrano, P., Maldera, S., Malyshev, D., Manfreda, A., Mazziotta, M. N., Michelson, P. F., Mirabal, N., Mitthumsiri, W., Mizuno, T., Moiseev, A. A., Monzani, M. E., Morselli, A., Moskalenko, I. V., Negro, M., Nuss, E., Orlando, E., Paneque, D., Perkins, J. S., Pesce-Rollins, M., Piron, F., Pivato, G., Porter, T. A., Principe, G., Rainò, S., Rando, R., Razzano, M., Reimer, A., Reimer, O., Sgrò, C., Simone, D., Siskind, E. J., Spada, F., Spandre, G., Spinelli, P., Tajima, H., Thayer, J. B., Tibaldo, L., Torres, D. F., Troja, E., Wood, M., Worley, A., Zaharijas, G., and Zimmer, S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: We present a measurement of the cosmic-ray electron+positron spectrum between 7 GeV and 2 TeV performed with almost seven years of data collected with the Fermi Large Area Telescope. We find that the spectrum is well fit by a broken power law with a break energy at about 50 GeV. Above 50 GeV, the spectrum is well described by a single power law with a spectral index of $3.07 \pm 0.02 \; (\text{stat+syst}) \pm 0.04 \; (\text{energy measurement})$. An exponential cutoff lower than 1.8 TeV is excluded at 95\% CL.
Published: 2017
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50. Fermi-LAT Observations of High-energy Behind-the-limb Solar Flares

Author: Ackermann, M., Allafort, A., Baldini, L., Barbiellini, G., Bastieri, D., Bellazzini, R., Bissaldi, E., Bonino, R., Bottacini, E., Bregeon, J., Bruel, P., Buehler, R., Cameron, R. A., Caragiulo, M., Caraveo, P. A., Cavazzuti, E., Cecchi, C., Charles, E., Ciprini, S., Costanza, F., Cutini, S., D'Ammando, F., de Palma, F., Desiante, R., Digel, S. W., Di Lalla, N., Di Mauro, M., Di Venere, L., Drell, P. S., Favuzzi, C., Fukazawa, Y., Fusco, P., Gargano, F., Giglietto, N., Giordano, F., Giroletti, M., Grenier, I. A., Guillemot, L., Guiriec, S., Jogler, T., Jóhannesson, G., Kashapova, L., Krucker, S., Kuss, M., La Mura, G., Larsson, S., Latronico, L., Li, J., Liu, W., Longo, F., Loparco, F., Lubrano, P., Magill, J. D., Maldera, S., Manfreda, A., Mazziotta, M. N., Mitthumsiri, W., Mizuno, T., Monzani, M. E., Morselli, A., Moskalenko, I. V., Negro, M., Nuss, E., Ohsugi, T., Omodei, N., Orlando, E., Pal'shin, V., Paneque, D., Perkins, J. S., Pesce-Rollins, M., Petrosian, V., Piron, F., Principe, G., Rainò, S., Rando, R., Razzano, M., Reimer, O., da Costa, F. Rubio, Sgrò, C., Simone, D., Siskind, E. J., Spada, F., Spandre, G., Spinelli, P., Tajima, H., Thayer, J. B., Torres, D. F., Troja, E., and Vianello, G.
Subjects: Astrophysics - Solar and Stellar Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract: We report on the Fermi-LAT detection of high-energy emission from the behind-the-limb (BTL) solar flares that occurred on 2013 October 11, and 2014 January 6 and September 1. The Fermi-LAT observations are associated with flares from active regions originating behind both the eastern and western limbs, as determined by STEREO. All three flares are associated with very fast coronal mass ejections (CMEs) and strong solar energetic particle events. We present updated localizations of the >100 MeV photon emission, hard X-ray (HXR)and EUV images, and broadband spectra from 10 keV to 10 GeV, as well as microwave spectra. We also provide a comparison of the BTL flares detected by Fermi-LAT with three on-disk flares and present a study of some of the significant quantities of these flares as an attempt to better understand the acceleration mechanisms at work during these occulted flares. We interpret the HXR emission to be due to electron bremsstrahlung from a coronal thin-target loop top with the accelerated electron spectra steepening at semirelativistic energies. The >100 MeV gamma-rays are best described by a pion-decay model resulting from the interaction of protons (and other ions) in a thick-target photospheric source. The protons are believed to have been accelerated (to energies >10 GeV) in the CME environment and precipitate down to the photosphere from the downstream side of the CME shock and landed on the front side of the Sun, away from the original flare site and the HXR emission., Comment: 13 pages, 14 figures published on ApJ
Published: 2017
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