Персона: Скорохватов, Михаил Дмитриевич
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Институт ядерной физики и технологий
Цель ИЯФиТ и стратегия развития - создание и развитие научно-образовательного центра мирового уровня в области ядерной физики и технологий, радиационного материаловедения, физики элементарных частиц, астрофизики и космофизики.
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Руководитель научной группы "Физика нейтрино и астрочастиц"
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Скорохватов
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Михаил Дмитриевич
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67 results
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- ПубликацияТолько метаданныеMeasurement of the ion fraction and mobility of 218Po produced in 222Rn decays in liquid argon(2019) Agnes, P.; Albuquerque, I. F. M.; Alexander, T.; Alton, A. K.; Grobov, A.; Machulin, I. N.; Nozdrina, A. O.; Skorokhvatov, M. D.; Wada, M.; Мачулин, Игорь Николаевич; Скорохватов, Михаил Дмитриевич© 2019 IOP Publishing Ltd and Sissa MedialabWe report measurements of the charged daughter fraction of 218Po as a result of the 222Rn alpha decay, and the mobility of 218Po+ ions, using radon-polonium coincidences from the 238U chain identified in 532 live-days of DarkSide-50 WIMP-search data. The fraction of 218Po that is charged is found to be 0.37 ± 0.03 and the mobility of 218Po+ is (8.6 ± 0.1) × 10−4 cm Vs2.
- ПубликацияТолько метаданныеDarkSide: Latest results and future perspectives(2019) Bottino, B.; Agnes, P.; Albuquerque, I. F. M.; Alexander, T.; MacHulin, I. N.; Nozdrina, A. O.; Skorokhvatov, M. D.; Мачулин, Игорь Николаевич; Скорохватов, Михаил Дмитриевич© 2019 CERN on behalf of the ATLAS Collaboration.DarkSide is direct-detection dark-matter experimental project based on radiopure argon. The main goal of the DarkSide program is the detection of rare nuclear elastic collisions with hypothetical dark-matter particles. The present detector, DarkSide-50, placed at Laboratori Nazionali del Gran Sasso (LNGS), is a dualphase time projection chamber (TPC) filled with ultra-pure liquid argon, extracted from underground sources. Surrounding the TPC to suppress the background there are neutron and muon active vetoes. One of argon key features is the capability to distinguish between electron and nuclear recoils, exploiting the different shapes of the signals. DarkSide-50 new results, obtained using a live-days exposure of 532.4 days, are presented. This analysis sets a 90% C.L. upper limit on the dark matternucleon spin-independent cross-section of 1.1 × 10-44 cm2 for a WIMP mass of 100 GeV/c2. The next phase of the project, DarkSide-20k, will be a new detector with a fiducial mass of ∼ 20 tons, equipped with cryogenic silicon photomultipliers (SiPM).
- ПубликацияТолько метаданныеLetter of interest for a neutrino beam from Protvino to KM3NeT/ORCA(2019) Akindinov, V.; Anassontzis, E. G.; Anton, G.; Ardid, M.; Litvinovich, E.; Skorokhvatov, M. D.; Литвинович, Евгений Александрович; Скорохватов, Михаил ДмитриевичThe Protvino accelerator facility located in the Moscow region, Russia, is in a good position to offer a rich experimental research program in the field of neutrino physics. Of particular interest is the possibility to direct a neutrino beam from Protvino towards the KM3NeT/ORCA detector, which is currently under construction in the Mediterranean Sea 40 km offshore Toulon, France. This proposal is known as P2O. Thanks to its baseline of 2595 km, this experiment would yield an unparalleled sensitivity to matter effects in the Earth, allowing for the determination of the neutrino mass ordering with a high level of certainty after only a few years of running at a modest beam intensity of sensitivity to the leptonic CP-violating Dirac phase can be achieved. A second stage of the experiment, comprising a further intensity upgrade of the accelerator complex and a densified version of the ORCA detector (Super-ORCA), would allow for up to a 6 sigma\documentclass[12pt] resolution on the CP phase after 10 years of running with a 450 kW beam, competitive with other planned experiments. The initial composition and energy spectrum of the neutrino beam would need to be monitored by a near detector, to be constructed several hundred meters downstream from the proton beam target. The same neutrino beam and near detector set-up would also allow for neutrino-nucleus cross section measurements to be performed. A short-baseline sterile neutrino search experiment would also be possible.
- ПубликацияТолько метаданныеDarkSide status and prospects(2019) Sanfilippo, S.; Agnes, P.; M, Albuquerque, I. F.; Alexander, T.; MacHulin, I. N.; Nozdrina, A. O.; Skorokhvatov, M. D.; Мачулин, Игорь Николаевич; Скорохватов, Михаил Дмитриевич© 2019 Societa Italiana di Fisica. All rights reserved.DarkSide uses a dual-phase Liquid Argon Time Projection Chamber to search for WIMP dark matter. The current detector, DarkSide-50, is running since mid 2015 with a target of 50 kg of Argon from an underground source. Here it is presented the latest results of searches of WIMP-nucleus interactions, with WIMP masses in the GeV-TeV range, and of WIMP-electron interactions, in the sub-GeV mass range. The future of DarkSide with a new generation experiment, involving a global collaboration from all the current Argon based experiments, is presented.
- ПубликацияТолько метаданныеCalibration of the liquid argon ionization response to low energy electronic and nuclear recoils with DarkSide-50(2021) Agnes, P.; Albuquerque, I. F. M.; Alexander, T.; Alton, A. K.; Grobov, A. V.; Machulin, I. N.; Nozdrina, A. O.; Skorokhvatov, M. D.; Мачулин, Игорь Николаевич; Скорохватов, Михаил Дмитриевич© 2021 American Physical Society. DarkSide-50 has demonstrated the high potential of dual-phase liquid argon time projection chambers in exploring interactions of WIMPs in the GeV/c2 mass range. The technique, based on the detection of the ionization signal amplified via electroluminescence in the gas phase, allows us to explore recoil energies down to the sub-keV range. We report here on the DarkSide-50 measurement of the ionization yield of electronic recoils down to ∼180 eVer, exploiting Ar37 and Ar39 decays, and extrapolated to a few ionization electrons with the Thomas-Imel box model. Moreover, we present a model-dependent determination of the ionization response to nuclear recoils down to ∼500 eVnr, the lowest ever achieved in liquid argon, using in situ neutron calibration sources and external datasets from neutron beam experiments.
- ПубликацияТолько метаданныеSensitivity of future liquid argon dark matter search experiments to core-collapse supernova neutrinos(2021) Agnes, P.; Albergo, S.; Albuquerque, I. F. M.; Alexander, T.; Grobov, A.; Machulin, I. N.; Skorokhvatov, M. D.; Мачулин, Игорь Николаевич; Скорохватов, Михаил Дмитриевич© 2021 IOP Publishing Ltd and Sissa Medialab.Future liquid-argon DarkSide-20k and Argo detectors, designed for direct dark matter search, will be sensitive also to core-collapse supernova neutrinos, via coherent elastic neutrino-nucleus scattering. This interaction channel is flavor-insensitive with a high-cross section, enabling for a high-statistics neutrino detection with target masses of ∼50 t and ∼360 t for DarkSide-20k and Argo respectively. Thanks to the low-energy threshold of ∼0.5 keVnr achievable by exploiting the ionization channel, DarkSide-20k and Argo have the potential to discover supernova bursts throughout our galaxy and up to the Small Magellanic Cloud, respectively, assuming a 11-M⊙ progenitor star. We report also on the sensitivity to the neutronization burst, whose electron neutrino flux is suppressed by oscillations when detected via charged current and elastic scattering. Finally, the accuracies in the reconstruction of the average and total neutrino energy in the different phases of the supernova burst, as well as its time profile, are also discussed, taking into account the expected background and the detector response.
- ПубликацияТолько метаданныеSensitivity of the SHiP experiment to light dark matter(2021) Ahdida, C.; Akmete, A.; Albanese, R.; Alexandrov, A.; Atkin, E.; Dmitrenko, V.; Etenko, A.; Filippov, K.; Grachev, V.; Kudenko, Y.; Novikov, A.; Polukhina, N.; Samsonov, V.; Shustov, A.; Skorokhvatov, M.; Smirnov, S.; Teterin, P.; Ulin, S.; Uteshev, Z.; Vlasik, K.; Аткин, Эдуард Викторович; Дмитренко, Валерий Васильевич; Этенко, Александр Владимирович; Грачев, Виктор Михайлович; Куденко, Юрий Григорьевич; Полухина, Наталья Геннадьевна; Шустов, Александр Евгеньевич; Скорохватов, Михаил Дмитриевич; Смирнов, Сергей Юрьевич; Тетерин, Пётр Евгеньевич; Улин, Сергей Евгеньевич; Утешев, Зияэтдин Мухамедович; Власик, Константин Федорович© 2021, The Author(s).Dark matter is a well-established theoretical addition to the Standard Model supported by many observations in modern astrophysics and cosmology. In this context, the existence of weakly interacting massive particles represents an appealing solution to the observed thermal relic in the Universe. Indeed, a large experimental campaign is ongoing for the detection of such particles in the sub-GeV mass range. Adopting the benchmark scenario for light dark matter particles produced in the decay of a dark photon, with αD = 0.1 and mA′ = 3mχ, we study the potential of the SHiP experiment to detect such elusive particles through its Scattering and Neutrino detector (SND). In its 5-years run, corresponding to 2 · 1020 protons on target from the CERN SPS, we find that SHiP will improve the current limits in the mass range for the dark matter from about 1 MeV to 300 MeV. In particular, we show that SHiP will probe the thermal target for Majorana candidates in most of this mass window and even reach the Pseudo-Dirac thermal relic. [Figure not available: see fulltext.]
- ПубликацияТолько метаданныеSearch for low-energy neutrinos from astrophysical sources with Borexino(2021) Agostini, M.; Altenmuller, K.; Appel, S.; Atroshchenko, V.; Litvinovich, E.; Machulin, I.; Skorokhvatov, M.; Литвинович, Евгений Александрович; Мачулин, Игорь Николаевич; Скорохватов, Михаил Дмитриевич© 2020We report on searches for neutrinos and antineutrinos from astrophysical sources performed with the Borexino detector at the Laboratori Nazionali del Gran Sasso in Italy. Electron antineutrinos (ν¯e) are detected in an organic liquid scintillator through the inverse β-decay reaction. In the present work we set model-independent upper limits in the energy range 1.8–16.8 MeV on neutrino fluxes from unknown sources that improve our previous results, on average, by a factor 2.5. Using the same data set, we first obtain experimental constraints on the diffuse supernova ν¯e fluxes in the previously unexplored region below 8 MeV. A search for ν¯e in the solar neutrino flux is also presented: the presence of ν¯e would be a manifestation of a non-zero anomalous magnetic moment of the neutrino, making possible its conversion to antineutrinos in the strong magnetic field of the Sun. We obtain a limit for a solar ν¯e flux of 384 cm–2 s–1 (90% C.L.), assuming an undistorted solar 8B neutrinos energy spectrum, that corresponds to a transition probability pνe→ν¯e< 7.2 × 10–5 (90% C.L.) for Eν¯e > 1.8 MeV. At lower energies, by investigating the spectral shape of elastic scattering events, we obtain a new limit on solar 7Be-νe conversion into ν¯e of pνe→ν¯e< 0.14 (90% C.L.) at 0.862 MeV. Last, we investigate solar flares as possible neutrino sources and obtain the strongest up-to-date limits on the fluence of neutrinos of all flavor neutrino below 3–7 MeV. Assuming the neutrino flux to be proportional to the flare's intensity, we exclude an intense solar flare as the cause of the observed excess of events in run 117 of the Cl-Ar Homestake experiment.
- ПубликацияТолько метаданныеSiPM-matrix readout of two-phase argon detectors using electroluminescence in the visible and near infrared range(2021) Aalseth, C. E.; Abdelhakim, S.; Agnes, P.; Ajaj, R.; Grobov, A.; Ilyasov, A.; Levashko, N.; Machulin, I. N.; Skorokhvatov, M. D.; Ильясов, Айдар Иршатович; Мачулин, Игорь Николаевич; Скорохватов, Михаил Дмитриевич© 2021, The Author(s).Proportional electroluminescence (EL) in noble gases is used in two-phase detectors for dark matter searches to record (in the gas phase) the ionization signal induced by particle scattering in the liquid phase. The “standard” EL mechanism is considered to be due to noble gas excimer emission in the vacuum ultraviolet (VUV). In addition, there are two alternative mechanisms, producing light in the visible and near infrared (NIR) ranges. The first is due to bremsstrahlung of electrons scattered on neutral atoms (“neutral bremsstrahlung”, NBrS). The second, responsible for electron avalanche scintillation in the NIR at higher electric fields, is due to transitions between excited atomic states. In this work, we have for the first time demonstrated two alternative techniques of the optical readout of two-phase argon detectors, in the visible and NIR range, using a silicon photomultiplier matrix and electroluminescence due to either neutral bremsstrahlung or avalanche scintillation. The amplitude yield and position resolution were measured for these readout techniques, which allowed to assess the detection threshold for electron and nuclear recoils in two-phase argon detectors for dark matter searches. To the best of our knowledge, this is the first practical application of the NBrS effect in detection science.
- ПубликацияТолько метаданныеIdentification of the cosmogenic 11 C background in large volumes of liquid scintillators with Borexino(2021) Agostini, M.; Altenmuller, K.; Appel, S.; Atroshchenko, V.; Litvinovich, E.; Machulin, I.; Nugmanov, R.; Skorokhvatov, M.; Литвинович, Евгений Александрович; Мачулин, Игорь Николаевич; Скорохватов, Михаил Дмитриевич© 2021, The Author(s).Cosmogenic radio-nuclei are an important source of background for low-energy neutrino experiments. In Borexino, cosmogenic 11C decays outnumber solar pep and CNO neutrino events by about ten to one. In order to extract the flux of these two neutrino species, a highly efficient identification of this background is mandatory. We present here the details of the most consolidated strategy, used throughout Borexino solar neutrino measurements. It hinges upon finding the space-time correlations between 11C decays, the preceding parent muons and the accompanying neutrons. This article describes the working principles and evaluates the performance of this Three-Fold Coincidence (TFC) technique in its two current implementations: a hard-cut and a likelihood-based approach. Both show stable performances throughout Borexino Phases II (2012–2016) and III (2016–2020) data sets, with a 11C tagging efficiency of ∼ 90 % and ∼ 63–66 % of the exposure surviving the tagging. We present also a novel technique that targets specifically 11C produced in high-multiplicity during major spallation events. Such 11C appear as a burst of events, whose space-time correlation can be exploited. Burst identification can be combined with the TFC to obtain about the same tagging efficiency of ∼ 90 % but with a higher fraction of the exposure surviving, in the range of ∼ 66–68 %.