741 research outputs found
Expression of Interest for a Full-Scale Detector Engineering Test and Test Beam Calibration of a Single-Phase LAr TPC
No full textFollowing the recommendation of the U.S. Particle Physics Project Prioritization Panel[1], Fermilab is working with the world neutrino community, CERN, and others to establish “a new international collaboration to design and execute a highly capable Long-Baseline Neutrino Facility (LBNF) hosted by the U.S.” This new collaboration, which is expected to be formed during the next several months, will combine, among others, groups that have been developing both single-phase and dual-phase LAr TPC detectors for long-baseline physics, mainly from the LBNE and LBNO collaborations respectively. This Expression of Interest regards a proposed full-scale prototype and beam test of the LBNE-design single-phase detector, utilizing the CERN Neutrino Platform[2] that was recently approved as part of the Medium-Term Plan (MTP) [3]. Once the LBNF collaboration is formed, it is expected that development of both single- and dual-phase detectors will come under the umbrella of the new collaboration
A Search for Ultra-high-energy Neutrinos from TXS 0506+056 Using the Pierre Auger Observatory
No full textInternational audienceResults of a search for ultra-high-energy neutrinos with the Pierre Auger Observatory from the direction of the blazar TXS 0506+056 are presented. They were obtained as part of the follow-up that stemmed from the detection of high-energy neutrinos and gamma rays with IceCube, Fermi-LAT, MAGIC, and other detectors of electromagnetic radiation in several bands. The Pierre Auger Observatory is sensitive to neutrinos in the energy range from 100 PeV to 100 EeV and in the zenith-angle range from θ = 60° to θ = 95°, where the zenith angle is measured from the vertical direction. No neutrinos from the direction of TXS 0506+056 have been found. The results were analyzed in three periods: one of 6 months around the detection of IceCube-170922 A, coinciding with a flare period of TXS 0506+056, a second one of 110 days during which the IceCube collaboration found an excess of 13 neutrinos from a direction compatible with TXS 0506+056, and a third one from 2004 January 1 up to 2018 August 31, over which the Pierre Auger Observatory has been taking data. The sensitivity of the Observatory is addressed for different spectral indices by considering the fluxes that would induce a single expected event during the observation period. For indices compatible with those measured by the IceCube collaboration the expected number of neutrinos at the Observatory is well below one. Spectral indices as hard as 1.5 would have to apply in this energy range to expect a single event to have been detected
The Angra Project: Monitoring Nuclear Reactors With Antineutrino Detectors
No full textWe present the status of the Angra Neutrino project, describing the development of an antineutrino detector aimed at monitoring nuclear reactor activity. The experiment will take place at the Brazilian nuclear power plant located in Angra dos Reis. The Angra II reactor, with 4 GW of thermal power, will be used as a source of antineutrinos. A water Cherenkov detector will be placed above ground in a commercial container outside the reactor containment, about 30 m from the reactor core. With a detector of one ton scale a few thousand antineutrino interactions per day are expected. We intend, in a first step, to use the measured neutrino event rate to monitor the on-off status and the thermal power delivered by the reactor. In addition to the safeguards issues the project will provide an alternative tool to have an independent measurement of the reactor power.1222427430Borovi, A.A., Mikaelyan, L.A., (1978) At. Energ., 44, pp. 508-511Korovkin, V.A., (1988) At. Energ., 65, pp. 169-173Bernstein, A., arXiv: 0980.4338 [nuclex]Anjos, J.C., (2006) Nucl.Phys. B (Proc. Suppl.), 155, p. 231Anjos, J.C., (2006) Braz. J. Phys., 36, p. 1118Anjos, J.C., Proc. NuFact08, , http://pos.sissa.it//archive/conferences/074/116/Nufact08116.pdf, Proceedings of Science(2008) Final Report: Focused Workshop on Antineutrino Detection for Safeguards Applications, , Vienna, IAEA Report STR-361Geant4 - A simulation toolkit (2003) Nucl. Instrum. Meth, A506, pp. 250-303Chimenti, P., Leigui De Oliveira, M.A., Lima, R.M., (2009) Proc. 5th Int. School on Field Theory and Gravitation, , http://pos.sissa.it//archive/conferences/081/056/ISFTG_056.pdf, Brazil. Proceedings of ScienceGonzalez, L.F.G., (2009), MSc Thesis, University of Campinas -UNICAMP, BrazilBowden, N.S., J. Appl. Phys, , submitted to. e-Print: arXiv: 0808.0698 [nucl-ex]Bezerra, T.J.C., (2009), MSc Thesis, University of Campinas - UNICAMP, Brazi
Performance of the 433 m surface array of the Pierre Auger Observatory
No full textThe Pierre Auger Observatory, located in western Argentina, is the world’s largest cosmic-ray observatory. While it was originally built to study the cosmic-ray flux above 1018.5 eV, several enhancements have reduced this energy threshold. One such enhancement is a surface array composed of a triangular grid of 19 water-Cherenkov detectors separated by 433 m (SD-433) to explore the energies down to about 1016 eV. We are developing two research lines employing the SD-433. Firstly, we will measure the energy spectrum in a region where previous experiments have shown evidence of the second knee. Secondly, we will search for ultra-high energy photons to study PeV cosmic-ray sources residing in the Galactic center. In this work, we introduce the SD-433 and we show that it is fully efficient above 5×1016 eV for hadronic primaries with θ < 45°. Using seven years of data, we present the parametrization of the lateral distribution function of measured signals. Finally, we show that an angular resolution of 1.8° (0.5°) can be attained at the lowest (highest) primary energies. Our study lays the goundmark for measurements in the energy range above 1016 eV by utilizing the SD-433 and thus expanding the scientific output of the Auger surface detector
Evidence for a mixed mass composition at the ‘ankle’ in the cosmic-ray spectrum
No full textWe report a first measurement for ultrahigh energy cosmic rays of the correlation between the depth of shower maximum and the signal in the water Cherenkov stations of air-showers registered simultaneously by the fluorescence and the surface detectors of the Pierre Auger Observatory. Such a correlation measurement is a unique feature of a hybrid air-shower observatory with sensitivity to both the electromagnetic and muonic components. It allows an accurate determination of the spread of primary masses in the cosmic-ray flux. Up till now, constraints on the spread of primary masses have been dominated by systematic uncertainties. The present correlation measurement is not affected by systematics in the measurement of the depth of shower maximum or the signal in the water Cherenkov stations. The analysis relies on general characteristics of air showers and is thus robust also with respect to uncertainties in hadronic event generators. The observed correlation in the energy range around the ‘ankle’ at lg(E/eV)=18.5–19.0lg(E/eV)=18.5–19.0 differs significantly from expectations for pure primary cosmic-ray compositions. A light composition made up of proton and helium only is equally inconsistent with observations. The data are explained well by a mixed composition including nuclei with mass A>4A>4. Scenarios such as the proton dip model, with almost pure compositions, are thus disfavored as the sole explanation of the ultrahigh-energy cosmic-ray flux at Earth
Erratum: Search for photons with energies above 1018 eV using the hybrid detector of the Pierre Auger Observatory (Journal of Cosmology and Astroparticle Physics (2017) 4 (9) DOI: 10.1088/1475-7516/2017/04/009)
No full text1 Exposure calculation Due to a mistake in the numerical integration following eq. (6.2) of the original article [1], the exposure shown in figure 5 of the original article was incorrect. The correct exposure is shown in figure 1. 2 Upper limits on the integral photon flux and fraction The incorrect exposure affects the calculation of the upper limits on the integral photon flux following eq. (6.1) of the original article. The correct values for the upper limits are 0.038, 0.010, 0.009, 0.008 and 0.007 km−2 sr−1 yr−1 for threshold energies of 1, 2, 3, 5 and 10 EeV. The correct values for the upper limits on the integral photon fraction subsequently derived are 0.14 %, 0.17 %, 0.42 %, 0.86 % and 2.9 % for the same threshold energies. 3 Author list The author list of this erratum also corrects a mistake made in the original article, where F. Zuccarello was missing and Z. Zong was listed twice
The second knee in the cosmic ray spectrum observed with the surface detector of the Pierre Auger Observatory
No full textThe determination of the energy spectrum features with low systematic uncertainty is crucial for interpreting the nature of cosmic rays. In this study, we conducted a measurement of the energy spectrum at the Pierre Auger Observatory using a surface detector with a calorimetric energy scale indirectly set by a fluorescence detector. The surface detector consists of an array of water-Cherenkov detectors that extends over 3000 km2 with 1500 m spacing. Additionally, two nested arrays of the same kind with 750 m and 433 m spacing were utilized to lower the energy threshold of the measurements. This contribution presents, for the first time, the spectrum measured with the 433 m array, which reduces the energy threshold down to 63 PeV, nearly half the energy at which we previously published a steepening using the 750 m array. Our measurements include a characterization of the spectral features of the flux steepening around 230 PeV, known as the second-knee. The study benefits from a nearly 100% duty cycle and geometrical exposure. Notably, this is the first simultaneous measurement of the second knee energy and spectral indexes before and after the break, using a surface detector with an energy scale predominantly independent of air shower simulations and assumptions regarding hadronic interaction models
A 3-Year Sample of Almost 1,600 Elves Recorded Above South America by the Pierre Auger Cosmic-Ray Observatory
No full textThe time and location of the 1,598
verified and reconstructed elves, used
for the analysis showcased in this
paper, are publicly available on the
website of the Pierre Auger
Observatory (https://www.auger.org/
index.php/science/data). We wish to
thank the World Wide Lightning
Location Network (http://wwlln.net),
a collaboration among over 50
universities and institutions, for
providing the lightning location data
used in this paper. We acknowledge
Robert Marshall for providing one of
the most advanced elve simulations to
the public, a key tool in understanding
the elves observed by the Pierre Auger
Observatory. The successful
installation, commissioning, and
operation of the Pierre Auger
Observatory would not have been
possible without the strong
commitment and effort from the
technical and administrative staff in
Malargüe.Elves are a class of transient luminous events, with a radial extent typically greater than
250 km, that occur in the lower ionosphere above strong electrical storms. We report the observation of
1,598 elves, from 2014 to 2016, recorded with unprecedented time resolution (100 ns) using the
fluorescence detector (FD) of the Pierre Auger Cosmic-Ray Observatory. The Auger Observatory is located
in the Mendoza province of Argentina with a viewing footprint for elve observations of 3 · 106 km2,
reaching areas above the Pacific and Atlantic Oceans, as well as the Córdoba region, which is known for
severe convective thunderstorms. Primarily designed for ultrahigh energy cosmic-ray observations, the
Auger FD turns out to be very sensitive to the ultraviolet emission in elves. The detector features modified
Schmidt optics with large apertures resulting in a field of view that spans the horizon, and year-round
operation on dark nights with low moonlight background, when the local weather is favorable. The
measured light profiles of 18% of the elve events have more than one peak, compatible with intracloud
activity. Within the 3-year sample, 72% of the elves correlate with the far-field radiation measurements of
the World Wide Lightning Location Network. The Auger Observatory plans to continue operations until at
least 2025, including elve observations and analysis. To the best of our knowledge, this observatory is the
only facility on Earth that measures elves with year-round operation and full horizon coverage.Argentina—Comisión Nacional de
Energía Atómica; Agencia Nacional de
Promoción Científica y Tecnológica
(ANPCyT); Consejo Nacional de
Investigaciones Científicas y Técnicas
(CONICET); Gobierno de la Provincia
de Mendoza; Municipalidad de
Malargüe; and NDM Holdings and
Valle Las Leñas, in gratitude for their
continuing cooperation over land
access; Australia—the Australian
Research Council; Brazil—Conselho
Nacional de Desenvolvimento
Científico e Tecnológico (CNPq);
Financiadora de Estudos e Projetos
(FINEP); Fundação de Amparo à
Pesquisa do Estado de Rio de Janeiro
(FAPERJ); São Paulo Research
Foundation (FAPESP) Grants
2010/07359-6 and 1999/05404-3;
Ministério da Ciência, Tecnologia,
Inovações e Comunicações
(MCTIC); Czech Republic—Grants
MSMT CRLTT18004,
LO1305, LM2015038, and
CZ.02.1.01/0.0/0.0/16_013/0001402;
France—Centre de Calcul
IN2P3/CNRS; Centre National de la
Recherche Scientifique (CNRS);
Conseil Régional Ile-de-France;
Département Physique Nucléaire et
Corpusculaire (PNC-IN2P3/CNRS);
Département Sciences de l'Univers
(SDU-INSU/CNRS); Institut Lagrange
de Paris (ILP) Grant LABEX
ANR-10-LABX-63 within the
Investissements d'Avenir Programme
Grant ANR-11-IDEX-0004-02;
Germany—Bundesministerium für
Bildung und Forschung (BMBF);
Deutsche Forschungsgemeinschaft
(DFG); Finanzministerium
Baden-Württemberg; Helmholtz
Alliance for Astroparticle Physics
(HAP); Helmholtz-Gemeinschaft. Deutscher Forschungszentren (HGF);
Ministerium für Innovation,
Wissenschaft und Forschung des
Landes Nordrhein-Westfalen;
Ministerium für Wissenschaft,
Forschung und Kunst des Landes
Baden-Württemberg; Italy—Istituto
Nazionale di Fisica Nucleare (INFN);
Istituto Nazionale di Astrofisica
(INAF); Ministero dell'Istruzione,
dell'Universitá e della Ricerca (MIUR);
CETEMPS Center of Excellence;
Ministero degli Affari Esteri (MAE);
México—Consejo Nacional de Ciencia
y Tecnología (CONACYT)167733;
Universidad Nacional Autónoma de
México (UNAM); PAPIIT
DGAPA-UNAM; The
Netherlands—Ministry of Education,
Culture and Science; Netherlands
Organisation for Scientific Research
(NWO); Dutch National
e-Infrastructure with the support of
SURF Cooperative; Poland—National
Centre for Research and Development,
Grant ERA-NET-ASPERA/02/11;
National Science Centre, Grants
2013/08/M/ST9/00322,
2016/23/B/ST9/01635, and
HARMONIA
5–2013/10/M/ST9/00062,
UMO-2016/22/M/ST9/00198;
Portugal—Portuguese national funds
and FEDER funds within Programa
Operacional Factores de
Competitividade through Fundação
para a Ciência e a Tecnologia
(COMPETE); Romania—Romanian
Ministry of Research and
InnovationCNCS/CCCDI-UESFISCDI,
projects PN-III-P1-1.2-PCCDI-2017-
0839/19PCCDI/2018,
PN-III-P2-2.1-PED-2016-1922,
PN-III-P2-2.1-PED-2016-1659, and
PN18090102 within PNCDI III;
Slovenia—Slovenian Research
Agency; Spain—Comunidad de
Madrid; Fondo Europeo de Desarrollo
Regional (FEDER) funds; Ministerio
de Economía y Competitividad; Xunta
de Galicia; European Community 7th
Framework Program Grant
FP7-PEOPLE-2012-IEF-328826;
USA—Department of Energy,
Contracts DE-AC02-07CH11359,
DE-FR02-04ER41300,
DE-FG02-99ER41107, and
DE-SC0011689; National Science
Foundation, Grant 0450696; The
Grainger Foundation; Marie
Curie-IRSES/EPLANET; European
Particle Physics Latin American
Network; European Union 7th
Framework Program, Grant
PIRSES-2009-GA-246806; and
UNESCO
Constraints on metastable superheavy dark matter coupled to sterile neutrinos with the Pierre Auger Observatory
No full textDark matter particles could be superheavy, provided their lifetime is much longer than the age of the Universe. Using the sensitivity of the Pierre Auger Observatory to ultrahigh energy neutrinos and photons, we constrain a specific extension of the Standard Model of particle physics that meets the lifetime requirement for a superheavy particle by coupling it to a sector of ultralight sterile neutrinos. Our results show that, for a typical dark coupling constant of 0.1, the mixing angle θm between active and sterile neutrinos must satisfy, roughly, θm ≲ 1.5 × 10−6(M X =10 9 GeV)−2 for a mass M X of the dark-matter particle between 108 GeV and 10 11 GeV
The energy spectrum of cosmic rays beyond the turn-down around 10^17 eV as measured with the surface detector of the Pierre Auger Observatory
No full textWe present a measurement of the cosmic-ray spectrum above 100 PeV using the part of the surface detector of the Pierre Auger Observatory that has a spacing of 750 m. An inflection of the spectrum is observed, confirming the presence of the so-called second-knee feature. The spectrum is then combined with that of the 1500 m array to produce a single measurement of the flux, linking this spectral feature with the three additional breaks at the highest energies. The combined spectrum, with an energy scale set calorimetrically via fluorescence telescopes and using a single detector type, results in the most statistically and systematically precise measurement of spectral breaks yet obtained. These measurements are critical for furthering our understanding of the highest energy cosmic rays
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