Search results for "Matter"
showing 10 items of 16762 documents
Crystal structure of bis-(allyl-ammonium) oxalate.
2014
The title salt, 2C3H8N+·C2O42−, crystallized with six independent allylammonium cations and three independent oxalate dianions in the asymmetric unit. One of the oxalate dianions is nearly planar [dihedral angle between CO2planes = 1.91 (19)°], while the other two are twisted with angles of 11.3 (3) and 26.09 (13)°. One cation has a synperiplanar (cis) conformation with an N—C—C—C torsion angle of 0.9 (3)°, whereas the five remaining cations are characterized bygauchearrangements, with the N—C—C—C torsion angles ranging from 115.9 (12) to 128.8 (3)°. One of the allylammonium cations is positionally disordered (fixed occupancy ratio = 0.45:0.55). In the crystal, the cations and anions are co…
A second solvatomorph of poly[[μ4-N,N′-(1,3,5-oxadiazinane-3,5-diyl)bis(carbamoylmethanoato)]nickel(II)dipotassium] : crystal structure, Hirshfeld su…
2021
The title compound, poly[triaquabis[μ4-N,N′-(1,3,5-oxadiazinane-3,5-diyl)bis(carbamoylmethanoato)]dinickel(II)tetrapotassium], [K4Ni2(C7H6N4O7)2(H2O)3] n , is a second solvatomorph of poly[(μ4-N,N′-(1,3,5-oxadiazinane-3,5-diyl)bis(carbamoylmethanoato)nickel(II)dipotassium] reported previously [Plutenko et al. (2021). Acta Cryst. E77, 298–304]. The asymmetric unit of the title compound includes two structurally independent complex anions [Ni(C7H6N4O7)]2−, which exhibit an L-shaped geometry and consist of two almost flat fragments perpendicular to one another: the 1,3,5-oxadiazinane fragment and the fragment including other atoms of the anion. The central Ni atom is in a square-planar N2O2 co…
Crystal structure, spectroscopic characterization and Hirshfeld surface analysis of trans-diaqua[2,5-bis(pyridin-4-yl)-1,3,4-oxadiazole]dithioc…
2019
The NiII atom in the mononuclear title complex has an almost regular octahedral N4O2 coordination geometry. In the crystal, the complex molecules are linked in a three-dimensional network through strong O—H⋯N hydrogen bonds.
Crystal structure of two N′-(1-phenylbenzylidene)-2-(thiophen-3-yl)acetohydrazides
2019
Two N′-(1-(phenylethylidene)-2-(thiophen-3-yl)acetohydrazides containing –OH and –OCH3 at the para-position of the phenyl ring have been synthesized and their molecular and crystal structures are reported.
Crystal structure of 5′′-benzylidene-1′-methyl-4′-phenyltrispiro[acenaphthylene-1,2′-pyrrolidine-3′,1′′-cyclohexane-3′′,2′′′-[1,3]dioxane]-2,6′′-dione
2016
In the title trispiro compound, both the methyl-substituted pyrrolidine and dioxalane rings adopt a twist conformation. The cyclopentanone ring of the acenapthylen-1-one system adopts flattened envelope conformation, and the cyclohexanone attached to the dioxalane ring adopts boat conformation. In the crystal, centrosymmetrically related molecules are linked into dimers forming rings of (10) graph-set motif, which are further connected into chains parallel to the b axis by C—H⋯O contacts forming rings of (8) graph-set motif.
Estimating QCD uncertainties in Monte Carlo event generators for gamma-ray dark matter searches
2018
Motivated by the recent galactic center gamma-ray excess identified in the Fermi-LAT data, we perform a detailed study of QCD fragmentation uncertainties in the modeling of the energy spectra of gamma-rays from Dark-Matter (DM) annihilation. When Dark-Matter particles annihilate to coloured final states, either directly or via decays such as $W^{(*)}\to q\bar{q}'$, photons are produced from a complex sequence of shower, hadronisation and hadron decays. In phenomenological studies, their energy spectra are typically computed using Monte Carlo event generators. These results have however intrinsic uncertainties due to the specific model used and the choice of model parameters, which are diffi…
Physics reach of the XENON1T dark matter experiment.
2016
The XENON1T experiment is currently in the commissioning phase at the Laboratori Nazionali del Gran Sasso, Italy. In this article we study the experiment's expected sensitivity to the spin-independent WIMP-nucleon interaction cross section, based on Monte Carlo predictions of the electronic and nuclear recoil backgrounds. The total electronic recoil background in $1$ tonne fiducial volume and ($1$, $12$) keV electronic recoil equivalent energy region, before applying any selection to discriminate between electronic and nuclear recoils, is $(1.80 \pm 0.15) \cdot 10^{-4}$ ($\rm{kg} \cdot day \cdot keV)^{-1}$, mainly due to the decay of $^{222}\rm{Rn}$ daughters inside the xenon target. The nu…
Measurement of the cosmic ray proton spectrum from 40 GeV to 100 TeV with the DAMPE satellite
2019
DAMPE satellite has directly measured the cosmic ray proton spectrum from 40 GeV to 100 TeV and revealed a new feature at about 13.6 TeV.
Edges and Endpoints in 21-cm Observations from Resonant Photon Production
2020
Physical review letters 127(1), 011102 (1-7) (2021). doi:10.1103/PhysRevLett.127.011102
Computational Techniques for the Analysis of Small Signals in High-Statistics Neutrino Oscillation Experiments
2020
The current and upcoming generation of Very Large Volume Neutrino Telescopes – collecting unprecedented quantities of neutrino events – can be used to explore subtle effects in oscillation physics, such as (but not restricted to) the neutrino mass ordering. The sensitivity of an experiment to these effects can be estimated from Monte Carlo simulations. With the high number of events that will be collected, there is a trade-off between the computational expense of running such simulations and the inherent statistical uncertainty in the determined values. In such a scenario, it becomes impractical to produce and use adequately-sized sets of simulated events with traditional methods, such as M…