Abstract
For the first time, a small dual-phase (liquid/gas) xenon time projection chamber was equipped with a top array of silicon photomultipliers for light and charge readout. Here we describe the ...instrument in detail, as well as the data processing and the event position reconstruction algorithms. We obtain a spatial resolution of
$$\sim 1.5\,\text {mm}$$
∼
1.5
mm
in the horizontal plane. To characterise the detector performance, we show calibration data with internal
$$^{83\text {m}}\hbox {Kr}$$
83
m
Kr
and
$$^{37}\hbox {Ar}$$
37
Ar
sources, and we detail the production of the latter as well as its introduction into the system. We finally compare the observed light and charge yields down to electronic recoil energies of
$$2.82\,\text {keV}$$
2.82
keV
to predictions based on NEST v2.0.
For the first time, a small dual-phase (liquid/gas) xenon time projection chamber was equipped with a top array of silicon photomultipliers for light and charge readout. Here we describe the ...instrument in detail, as well as the data processing and the event position reconstruction algorithms. We obtain a spatial resolution of
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\begin{document}$$\sim 1.5\,\text {mm}$$\end{document}
∼
1.5
mm
in the horizontal plane. To characterise the detector performance, we show calibration data with internal
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\begin{document}$$^{83\text {m}}\hbox {Kr}$$\end{document}
83
m
Kr
and
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\begin{document}$$^{37}\hbox {Ar}$$\end{document}
37
Ar
sources, and we detail the production of the latter as well as its introduction into the system. We finally compare the observed light and charge yields down to electronic recoil energies of
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\begin{document}$$2.82\,\text {keV}$$\end{document}
2.82
keV
to predictions based on NEST v2.0.
Xenon dual-phase time projections chambers (TPCs) have proven to be a successful technology in studying physical phenomena that require low-background conditions. With
40
t
of liquid xenon (LXe) in ...the TPC baseline design, DARWIN will have a high sensitivity for the detection of particle dark matter, neutrinoless double beta decay (
0
ν
β
β
), and axion-like particles (ALPs). Although cosmic muons are a source of background that cannot be entirely eliminated, they may be greatly diminished by placing the detector deep underground. In this study, we used Monte Carlo simulations to model the cosmogenic background expected for the DARWIN observatory at four underground laboratories: Laboratori Nazionali del Gran Sasso (LNGS), Sanford Underground Research Facility (SURF), Laboratoire Souterrain de Modane (LSM) and SNOLAB. We present here the results of simulations performed to determine the production rate of
137
Xe, the most crucial isotope in the search for
0
ν
β
β
of
136
Xe. Additionally, we explore the contribution that other muon-induced spallation products, such as other unstable xenon isotopes and tritium, may have on the cosmogenic background.
We correct an overestimation of the production rate of
137
Xe in the DARWIN detector operated at LNGS. This formerly dominant intrinsic background source is now at a level similar to the irreducible ...background from solar
8
B neutrinos, thus unproblematic at the LNGS depth. The projected half-life sensitivity for the neutrinoless double beta decay (
0
ν
β
β
) of
136
Xe improves by
22
%
compared to the previously reported number and is now
T
1
/
2
0
ν
=
3.0
×
10
27
yr
(90% C.L.) after 10 years of DARWIN operation.
Abstract We correct an overestimation of the production rate of $$^{137}$$ 137 Xe in the DARWIN detector operated at LNGS. This formerly dominant intrinsic background source is now at a level similar ...to the irreducible background from solar $$^8$$ 8 B neutrinos, thus unproblematic at the LNGS depth. The projected half-life sensitivity for the neutrinoless double beta decay ( $$0\nu \beta \beta $$ 0 ν β β ) of $$^{136}$$ 136 Xe improves by $$22\%$$ 22 % compared to the previously reported number and is now $$T^{0\nu }_{1/2}= {3.0\times 10^{27}} \hbox { yr}$$ T 1 / 2 0 ν = 3.0 × 10 27 yr (90% C.L.) after 10 years of DARWIN operation.
ABSTRACT IN FRENCH: Renovelant sa perspective, Coase lance un défi comptable: la spécificité du système comptable interne par rapport au système des prix serait le reflet de la distinction entre ...firme et marchés, donc l'un des fondements de la nature économique de l'entreprise. Tandis que les approches contractualistes ne semblent pas emprunter cette piste, une vue comptable dynamique peut appréhender le processus économique accompli au sein de l'entreprise, qu'elle distingue des marchés qui y sont impliqués, qu'il s'agisse des marchés des facteurs (capital, travail) ou des produits et services. Cette vue permet d'intégrer le système comptable dans la structure institutionnelle de la production en tant que mode de régulation et d'organisation. Cette vue appréhende ainsi la place et le rôle spécifiques qu'ont la gestion et l'organisation économique interne dans la création et l'allocation des ressources, et permet de concevoir la nature économique de l'entreprise comme une entité fonctionnelle et institutionnelle. // ABSTRACT IN ENGLISH: If the theoretical question of the nature of the firm is raised, the role of accounting system in the allocation of resources seems naturally be called for inquiry. However, in spite of the suggestion of the leading scholar Coase R. (1990), all the new theories of the firm disregard such critical economic function of accounting, probably because their methodological contractualism is unable to capture it. On the contrary, a dynamic accounting approach can answer to the Coasian appeal and explore the accounting system as an integral part of the institutional structure of production. By means of accounting, the economic and monetary process of the firm acquires functional and institutional existence, independent from external markets for factors or products. Thus, the accounting system defines the economic activity of the firm as an enterprise entity, and its impact on the creation and allocation of resources is clearer recognised.
The paper addresses two distinct aspects of disharmony in international accounting standards setting. The first aspect relates to the political economic context of financial accounting standards. ...This is illustrated by the Chinese standards setters’ decision to allow the pooling of interests method of accounting for business combinations despite the prohibition of this method by both the FASB and the IASB. This decision by the Chinese standards setters appears to have been based on political economic factors related to the need for industrial reorganization in China rather than a desire to serve the needs of global capital markets. The second aspect of disharmony relates to the role played by differential understandings of the fundamental objectives of financial reporting in an international context. The IASB's goal of producing one set of global accounting standards to serve the needs of global capital markets has led to a reduction in the number of permissible accounting methods and a move towards the fair value accounting model. In particular, the IASB concluded that the acquisition method of accounting for business combinations should be the only method allowed for business combinations. In contrast, the Chinese standards setters have recognized the existence of both mergers and acquisitions, and in response they created two different methods of accounting for business combinations. Effectively, the Chinese standards setters developed an alternative approach to accounting for business combinations which challenges the IASB's goal of achieving international accounting convergence through the fair value model.
Abstract The DARWIN observatory is a proposed next-generation experiment to search for particle dark matter and for the neutrinoless double beta decay of $$^{136}$$ 136 Xe. Out of its 50 t total ...natural xenon inventory, 40 t will be the active target of a time projection chamber which thus contains about 3.6 t of $$^{136}$$ 136 Xe. Here, we show that its projected half-life sensitivity is $$2.4\times {10}^{27}\,{\hbox {year}}$$ 2.4×1027year , using a fiducial volume of 5 t of natural xenon and 10 year of operation with a background rate of less than 0.2 events/(t $$\cdot $$ · year) in the energy region of interest. This sensitivity is based on a detailed Monte Carlo simulation study of the background and event topologies in the large, homogeneous target. DARWIN will be comparable in its science reach to dedicated double beta decay experiments using xenon enriched in $$^{136}$$ 136 Xe.
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