422 research outputs found
The cocrystal 10-(2-methyl-4-phenyl-1H-inden-6-yl)-10H-phenothiazine–10-(2-methyl-7-phenyl-1H-inden-5-yl)-10H-phenothiazine (0.54/0.46)
The title compound, 0.535C28H21NS.0.465C28H21NS, was synthesized by palladium-catalysed amination. The structure is composed of two isomeric molecules, viz. 10-(2-methyl-4-phenyl-1H-inden-6-yl)-10H-phenothiazine, and 10-(2-methyl-7-phenyl-1H-inden-5-yl)-10H-phenothiazine, in the refined ratio 0.535 (12):0.465 (12). The isomers differ by the localization of the double bond in the cyclopentadiene ring. There are two sites in the structure that are occupied by the isomers. The respective isomers are occupationally disordered in each site, the refined proportions being 0.640 (6):0.360 (6) and 0.43 (1):0.57 (1). Moreover, each isomeric molecule is chiral; due to the crystallographic centres of symmetry, the molecules are also present in enantiomeric pairs. The crystal structure is stabilized by weak π–π [C⋯C = 3.389 (2) Å] interactions
Clusters of primordial black holes
The Primordial Black Holes (PBHs) are gradually involved into consideration
as the phenomenon having reliable basis. We discuss here the possibility of
their agglomeration into clusters that may have several prominent observable
features. The clusters can form due to closed domain walls appearance in the
natural and the hybrid inflation with subsequent evolution and gravitational
collapse. Early dustlike stages of dominance of heavy metastable dissipative
particles, at which star-like objects are formed, can also naturally lead to
formation of black hole clusters, remaining in the Universe after decay of
particles, from which they have originated. The dynamical evolution of such
clusters discussed here is of the crucial importance. Such a model inherits all
the advantages of the single PBHs like possible explanation of existence of
supermassive black holes (origin of the early quasars), binary BH merges
registered by LIGO/Virgo through gravitational waves, contribution to
reionization of the Universe, but also has additional benefits. The cluster
could alleviate or completely avoid existing constraints on the single PBH
abundance making PBHs a real dark matter candidate. The most of existing
constraints on (single) PBH density should be re-considered as applied to the
clusters. Also unidentified cosmic gamma-ray point-like sources could be
(partially) accounted for by them. One can conclude, that it seems really to be
much more viable model with respect to the single PBHs.Comment: v2: both the text and bibliography are essentially extended,
coincides with EPJC versio
Osinskaya subformation of the Usolsky formation of the Lower Cambrian of the central and southern parts of the Nepa-Botuoba anteclise: structure, formation conditions and biostratigraphical characteristics
Relevance. Geological prospecting carried out recently throughout the Lena-Tunguska oil-and-gas province makes studies of carbonates of the Osinskaya subformation particularly relevant, as they make it possible to establish the patterns of hydrocarbon trap formation. Aim. To present the results of the lithological and facial, biostratigraphic and petrophysical studies of the Osinskaya subformation in the southern and central part of the Nepa-Botuoba anteclise. Objects. Carbonate rocks of the middle Osinskaya subformation of the Usolskiy Formation of the Lower Cambrian Tommotian Stage, studied from well cores. Methods. GIS complex, detailed lithological and sedimentological description of the core, sequential stratigraphic analysis, petrographic analysis of 300 samples and examination of paleontological remains taken from the core; analysis. Results. Based on these studies, three sedimentation zones were identified, traced, and described for the first time: deep-water, marginal, and shallow-water. The deep-water zone is characterized by uncompensated sedimentation, the presence of single reefs, and confinement to depressions and troughs. It was flanked by an edge zone of carbonate platform associated with elevated thicknesses of the subformation and distribution of reefs over the area. It was followed by a shallow-water zone, represented by medium and reduced thicknesses of the Osinskaya subformation, its sediments are composed of carbonate grained and clayey rocks with small single reefs. The localized marginal zone of the extended carbonate platform agrees with the previously identified Chambinsko-Altybsko-Mirninskaya and Verkhnetokhomsko-Katsko-Pilyudinskaya zones of distribution of reef-like organogenic structures. On the basis of the studied wells, the structure of three formations according to the lithologic-facial profile was described. The paper introduces the authors’ variant of conducting the boundaries of the members. It was revealed that in the deep-water zone the prospects of searching for reservoir rocks are associated with single carbonate structures, in the marginal zone with area bioherms, and in the shallow-water zone with detrital deposits and shallow bioherms. The paleontological finds are shown to be confined to the selected sedimentation zones and beds. It was determined that algae diagnosed in the boudstones (autochthonous) were involved in the formation of the second and third strata, the edge zone of the carbonate platform. Archaeocyaths were diagnosed in detrital carbonate rocks of the second pack (allochthonous) in well no. 7 and autochthonous in boudstones of well no. 2X. Cribriciates were diagnosed in the boudstones of the third member (autochthonous). Archaeocyaths, cribriciates, namacalatusses, and calcareous algae studied from the cores of wells West Yaractinian no. 45, 361, Bolshetyrskaya no. 7, 3X, 2X, 4X, 5X, 6X were major edificators of Early Cambrian organogenic structures (biostromes, bioherms, bioherms massifs, reef formations)
Challenges in QCD matter physics - The Compressed Baryonic Matter experiment at FAIR
Substantial experimental and theoretical efforts worldwide are devoted to
explore the phase diagram of strongly interacting matter. At LHC and top RHIC
energies, QCD matter is studied at very high temperatures and nearly vanishing
net-baryon densities. There is evidence that a Quark-Gluon-Plasma (QGP) was
created at experiments at RHIC and LHC. The transition from the QGP back to the
hadron gas is found to be a smooth cross over. For larger net-baryon densities
and lower temperatures, it is expected that the QCD phase diagram exhibits a
rich structure, such as a first-order phase transition between hadronic and
partonic matter which terminates in a critical point, or exotic phases like
quarkyonic matter. The discovery of these landmarks would be a breakthrough in
our understanding of the strong interaction and is therefore in the focus of
various high-energy heavy-ion research programs. The Compressed Baryonic Matter
(CBM) experiment at FAIR will play a unique role in the exploration of the QCD
phase diagram in the region of high net-baryon densities, because it is
designed to run at unprecedented interaction rates. High-rate operation is the
key prerequisite for high-precision measurements of multi-differential
observables and of rare diagnostic probes which are sensitive to the dense
phase of the nuclear fireball. The goal of the CBM experiment at SIS100
(sqrt(s_NN) = 2.7 - 4.9 GeV) is to discover fundamental properties of QCD
matter: the phase structure at large baryon-chemical potentials (mu_B > 500
MeV), effects of chiral symmetry, and the equation-of-state at high density as
it is expected to occur in the core of neutron stars. In this article, we
review the motivation for and the physics programme of CBM, including
activities before the start of data taking in 2022, in the context of the
worldwide efforts to explore high-density QCD matter.Comment: 15 pages, 11 figures. Published in European Physical Journal
Measurement of charm production at central rapidity in proton-proton collisions at TeV
The -differential production cross sections of the prompt (B
feed-down subtracted) charmed mesons D, D, and D in the rapidity
range , and for transverse momentum GeV/, were
measured in proton-proton collisions at TeV with the ALICE
detector at the Large Hadron Collider. The analysis exploited the hadronic
decays DK, DK, DD, and their charge conjugates, and was performed on a
nb event sample collected in 2011 with a
minimum-bias trigger. The total charm production cross section at TeV and at 7 TeV was evaluated by extrapolating to the full phase space
the -differential production cross sections at TeV
and our previous measurements at TeV. The results were compared
to existing measurements and to perturbative-QCD calculations. The fraction of
cdbar D mesons produced in a vector state was also determined.Comment: 20 pages, 5 captioned figures, 4 tables, authors from page 15,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/307
Sensitivity projections for a dual-phase argon TPC optimized for light dark matter searches through the ionization channel
Dark matter lighter than 10 GeV/c encompasses a promising range of
candidates. A conceptual design for a new detector, DarkSide-LowMass, is
presented, based on the DarkSide-50 detector and progress toward DarkSide-20k,
optimized for a low-threshold electron-counting measurement. Sensitivity to
light dark matter is explored for various potential energy thresholds and
background rates. These studies show that DarkSide-LowMass can achieve
sensitivity to light dark matter down to the solar neutrino floor for GeV-scale
masses and significant sensitivity down to 10 MeV/c considering the Migdal
effect or interactions with electrons. Requirements for optimizing the
detector's sensitivity are explored, as are potential sensitivity gains from
modeling and mitigating spurious electron backgrounds that may dominate the
signal at the lowest energies
KK correlations in pp collisions at TeV from the LHC ALICE experiment
Identical neutral kaon pair correlations are measured in TeV pp
collisions in the ALICE experiment. One-dimensional KK correlation
functions in terms of the invariant momentum difference of kaon pairs are
formed in two multiplicity and two transverse momentum ranges. The femtoscopic
parameters for the radius and correlation strength of the kaon source are
extracted. The ft includes quantum statistics and final-state
interactions of the a/f resonance. KK correlations show an
increase in radius for increasing multiplicity and a slight decrease in radius
for increasing transverse mass, , as seen in correlations
in the pp system and in heavy-ion collisions. Transverse mass scaling is
observed between the KK and radii. Also, the frst
observation is made of the decay of the f(1525) meson into the
KK channel in pp collisions.Comment: 17 pages, 7 captioned figures, 2 tables, authors from page 12,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/310
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