598 research outputs found
Measurement of - beta-spectra with Si(Li) detectors for the purpose of determining the spectra of electron antineutrinos.
No full textS.V. Bakhlanov, A.V. Derbin, I.S. Drachnev, V.N. Muratova, N.V. Pilipenko, D.A. Semenov, E.V. Unzhakov
St. Petersburg Nuclear Physics Institute National Research Center “Kurchatov Institute”, Gatchina, Russia
The specifications of a newly developed beta-spectrometer, based on full absorption Si(Li) detector and thin transmission detector, are shown. The spectrometer allows to separate effectively beta-radiation and accompanying X-rays and gamma radiation using registration of coincident events from both detectors. The spectrometer can be used for precision measurements of various beta-spectra, namely for the beta-spectrum shape study of 144Pr
^{144}\rm{Pr}
, which is considered to be an advantageous anti-neutrino source for sterile neutrino searches. The preliminary results for beta spectra from 144Ce−144Pr
^{144}\rm{Ce}-^{144}\rm{Pr}
decays and reconstructed antineutrino spectra are presented
Search for low-energy Borexino's signals correlated with gamma-ray bursts, solar flares and gravitational wave events.
No full textA.V. Derbin for the Borexino collaboration The results of a low-energy neutrino search using the Borexino detector in coincidence with gamma-ray bursts (GRB), solar flares (SF) and gravitational wave (GW) events are presented. The correlated events with energies greater than 0.25 (1.0) MeV were looked for within a various time windows centered around the GRB, SF or GW detection time. As a result, we have obtained the best current upper limits on all flavor neutrino fluences associated with these astrophysical sources for neutrino energy below 5-7 MeV
Search for resonant absorption of solar axions by nuclei
No full textA.V. Derbin, I.S. Drachnev, Yu.M. Gavrilyuk, A.M. Gangapshev, V.V. Kazalov,V.V.Kuzminov,V.N. Muratova, S.I. Panasenko, S.S. Ratkevich, D.A. Tekueva, E.V.Unzhakov, S.P. Yakimenko
A search for resonant absorption of the solar axions with a wide continuous spectra by nuclei is continued with the krypton proportional counter at the Baksan Neutrino Observatory. Such an absorption should lead to the excitation of low-lying nuclear energy level of . The results obtained after 613 days of measurements allow to constraint on the axion–photon coupling and axion mass for Primakoff solar axions. This bound corresponds to the upper limit on KSVZ axion mass eV. For solar axions produced by Compton and bremsstrahlung like processes the limit on axion-electron coupling and KSVZ axion mass are ~eV and eV, correspondingly (all at 95\% C.L.)
Search for resonant absorption of solar axions by nuclei
No full textA.V. Derbin, I.S. Drachnev, Yu.M. Gavrilyuk, A.M. Gangapshev, V.V. Kazalov,V.V.Kuzminov,V.N. Muratova, S.I. Panasenko, S.S. Ratkevich, D.A. Tekueva, E.V.Unzhakov, S.P. Yakimenko
A search for resonant absorption of the solar axions with a wide continuous spectra by nuclei is continued with the krypton proportional counter at the Baksan Neutrino Observatory. Such an absorption should lead to the excitation of low-lying nuclear energy level of . The results obtained after 613 days of measurements allow to constraint on the axion–photon coupling and axion mass for Primakoff solar axions. This bound corresponds to the upper limit on KSVZ axion mass eV. For solar axions produced by Compton and bremsstrahlung like processes the limit on axion-electron coupling and KSVZ axion mass are ~eV and eV, correspondingly (all at 95\% C.L.)
The Lukewarm Frontier: Some Cosmological Consequences of 'Low Energy' Physics
No full textIn this thesis, we present four projects featuring low characteristic energy scales relative to the scales relevant for supersymmetric dark matter production or inflation. We present a telescope search for decaying relic axions in the 3 − 8 eV mass range. We utilize larger telescope exposure and superior cluster mass modeling to improve sensitivity. Our results impose new stringent limits to the two-photon coupling or relic density of axions. We extend these results to non-standard sterile neutrinos.
We then reconsider cosmological constraints to axions. Our understanding of physics before big-bang nucleosynthesis is tenuous, and after arguing that a non-standard thermal history before nucleosynthesis is plausible and perhaps even natural, we calculate the abundance and typical momenta of thermal axions in such scenarios. We generalize existing cosmological constraints to axions, showing that the allowed axion mass range expands significantly in non-standard thermal histories. We then estimate the sensitivity of future experiments to axion masses and reheating temperatures.
We then study the ~ eV-scale physics of cosmological hydrogen ~ 10^4 states of hydrogen up to a maximum n ~ 250, and studying the associated convergence problem. We show that the recombination history is sufficiently converged for analysis of microwave anisotropy data from the Planck satellite if the maximum n ~ 128, and that previously ignored electric quadrupole transitions are indeed negligible to the precision necessary for Planck.
We conclude by presenting a new astrophysical limit to effective field theories of gravity in which the graviton propagator is damped at energies greater than a milli-eV.</p
Search for axioelectric effect of solar axions using BGO scintillating bolometer
No full textA search for axioelectric absorption of solar axions produced in the (Formula presented.) reaction has been performed with a BGO detector placed in a low-background setup. A model-independent limit on the combination of axion-nucleon and axion-electron coupling constants has been obtained: (Formula presented.) for 90 % confidence level. The constraint of the axion-electron coupling constant has been obtained for hadronic axion with masses of (0.1-1) MeV: (Formula presented.). © 2014 The Author(s)
Eurasianism and M. V. Shakhmatov (Distinction between Viewpoints Revisited)
No full textThe article is dedicated to emigrant historian M. V. Shakhmatov, the creator of the ‘State of Truth’ theory resulting from his analysis of ancient Russian literary and folklore compositions. Its basis was constituted by the concepts of sobornost (‘cooperation’), odinachestvo (‘equality’) and divine nature of political power. Despite present-day studies, it is quite difficult to consider it ‘Eurasianistic’ by nature though its author got a number his works printed in several volumes of the Eurasianists. In his papers there are no such ideas as the ‘outcome to the East’, decisive factor of development place, perception of Russia as Eurasia or the idea of struggle as the driving force of history; finally, there was no Eurasianistic understanding of the benefits of the Mongol invasion. Ideologists of Eurasianism considered M. V. Shakhmatov to be a temporary companion of theirs who was used merely as a ‘specialist’. In turn, he declared his break with them. In general, his views can be rather attributed to the revival of Slavophile ideas about the uniqueness of Russia’s historical path and its sharp contrast to the West. They stemmed not from the Eurasianistic movement but from personal searches in the course of work on a master’s thesis on the history of ancient political ideas.The article analyzes M. V. Shakhmatov’s views, the circumstances of the appearance of his works in the Eurasianistic Vremennik, reflects the Eurasianists’ opinions about the author contained in the correspondence of G. V. Florovsky to N. S. Troubetzkoy, N. S. Troubetzkoy to P. P. Sovchinski. This correspondence has not been taken into account by previous researchers of M. V. Shakhmatov’s works which resulted in somewhat incorrect conclusions. Given the relevance of the study of Eurasianism as a whole, and the Eurasianistic concept of Russian history in particular, the distinction between viewpoints of M. V. Shakhmatov and Eurasianists will allow to avoid many errors in future publications. It may contribute to further detailed consideration of Eurasianistic compositions by representative of the 1920–1930s Russian emigration
Chaotic Representation of the Relationships between Princes in the Ancient Rus’
No full textThe review analyses the monograph by D. A. Borovkov “Relationships between princes in Rus’
in the late X — in the first quarter of the XII century and their representation in the sources and
historiography”. The work professes to contain general conclusions with respect to the research
topic, which is a pivotal topic in the Russian historiography of the middle ages. The author aims
at “reconsidering the question of the essence of the relationships between princes during the
initial stage of their development with a view to determining the degree of correspondence between
the “material of the sources” and any of the historiographical theories related to the field of
research, if possible”. This is where the main drawback of the monograph lies. The historiographical
theories the monograph refers to are not substantiated; contain numerous errors, gaps; often
represent frequently confused phrases and conclusions. The historical part of the work looks
better. The author sometimes boldly resolves minor issues relating to, for example, the questions
about where and when a particular prince reigned. However, the author, more often relies on
the opinion of A. A. Shakhmatov, trusting him a priori, or refers to the textual reconstructions of
other researchers. Thus, the monograph presents a skillful compilation from historiographical
conclusions by many researchers. The findings of Borovkov are the following. The relationships
between princes in Rus’ since the first division of principalities by Svyatoslav Igorevich in 970 are
presented as the development of collective co-ownership where the members of the princely
family, who had the right to participate in management, were equal. Only at the turn of the
XI–XII centuries the doctrine of the priority of “the oldest brother”, which the sources was associated
with the preceding period, was formulated in Pechersk monastery. However, the struggle
of “younger” princes for their rights made the “votchinny” (patrimonial) principle of succession
proclaimed as the official doctrine at the Council of Liubech in 1097 politically relevant during
that period. The princes’aspirations to individual power was perceived negatively. It remains unclear
to the reviewer where the author reconsiders the questions of the essence of the relationships
between princes and why he arrives at the final conclusion, contradicting the whole work,
that the relationships between princes in Rus’ can be characterized as kinship
LYSAN ALKALINE-ULTRABASIC COMPLEX (EASTERN SAYAN): AGE AND GEODYNAMIC CONSEQUENCES
No full textThis paper presents new ideas about the formational identity, as well as the first data on the age of formation of rocks within the Lysan intrusive complex located at junction of the Derbin block and the Sisim-Kazyr zone of the Central Asian folded belt. The study identified the similarities between the Lysan complex and intrusions of the alkaline-ultrabasic formation. It formed during the period of maximum intraplate activity along the edge of the Siberian craton
The problem of the supreme political authority in the Ancient Rus’ in the works of russian émigré legal historians in harbin
No full textThe paper deals with the views of Russian émigré historians of law in Harbin (G.G. Telberg, K.I. Zaitsev,
N.E. Esperov) regarding the supreme authority in the Ancient Rus’. The author analyses supreme
authority institutes, such as princely power, veche, boyar (princely) duma, and quite a broad range
of related historiography problems, demonstrating what those historians, who taught at the Faculty
of Law at Harbin University in the 1920–30s, had in common and in what ways they differed in their
approaches, as well as finding in their works traces of prerevolutionary historiographical agenda and
outlining their own ways of thinking that were brought to an end by the WWII. The conclusion is that,
even though they belonged to different schools of thought and generations, the Russian historians of
law who ended up in Harbin agreed on the tripartite structure of the supreme authority in the Ancient
Rus’. Refs 18
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