22 research outputs found
Electrical and optical properties of a PtSn 4 single crystal
A topological semimetal PtSn4 single crystal was grown by method of crystallization from a solution in a melt. Then the electrical resistivity and galvanomagnetic properties (magnetoresistivity and the Hall effect) were studied in the temperature range from 4.2 to 80 K and in magnetic fields up to 100 kOe. The optical measurements were carried out at room temperature. The residual resistivity is shown to be low enough and amount to ∼ 0.5 μOhm•cm. The temperature dependence of the electrical resistivity has a metallic type, increasing monotonically with temperature. A sufficiently large magnetoresistance of 750% is observed. The majority carriers are supposed to be holes with a concentration of ∼ 6.8•10 21 cm -3 and mobility of ∼ 1950 cm 2 /Vs at T = 4.2 K as a result of the Hall effect studies. The optical properties of PtSn 4 have features characteristic of "bad" metals. © 2019 Published under licence by IOP Publishing Ltd.This work was partly supported by the state assignment of Russia (theme “Spin” No. АААА-А18-18020290104-2 and theme “Electron” No. АААА-А18-118020190098-5), by the RFBR (project No.17-52-52008) and by the Government of the Russian Federation (state contract No. 02.A03.21.0006)
Influence of Co spin-state on optical properties of LaCoO and HoCoO
Optical properties of the isoelectronic compounds LaCoO and HoCoO has
been experimentally and theoretically investigated. We've measured the real
and imaginary parts of the dielectric
function, reflectance and optical conductivity at room temperature.
The shift of the most pronounced spectral features to the high energy region on
0.3 eV associated with larger distortions due to the smaller rare earth ionic
radii in HoCoO in comparison with LaCoO was observed. Also there was
found an enhancement of absorption intensity in the range 1.3-2.3 eV in all
kinds of spectra in HoCoO, which can be attributed basing on the results of
LDA+U calculations to the different spin-states of Co ion in these
compounds. The shift of the onset of the absorption from less than 0.1 eV in
LaCoO to 0.7 eV in HoCoO and an absorption intensity enhancement in a
narrow spectral range 1.2-2.6 eV in HoCoO are clearly seen from the
calculated convolution of partial densities of states obtained in the LDA+U
approach. Such changes are assumed to be induced by the different Co
spin-state in these compounds at room temperature.Comment: 10 pages, 3 figure
Production of {\pi}+ and K+ mesons in argon-nucleus interactions at 3.2 AGeV
First physics results of the BM@N experiment at the Nuclotron/NICA complex
are presented on {\pi}+ and K+ meson production in interactions of an argon
beam with fixed targets of C, Al, Cu, Sn and Pb at 3.2 AGeV. Transverse
momentum distributions, rapidity spectra and multiplicities of {\pi}+ and K+
mesons are measured. The results are compared with predictions of theoretical
models and with other measurements at lower energies.Comment: 29 pages, 20 figure
The HITRAN2020 Molecular Spectroscopic Database
The HITRAN database is a compilation of molecular spectroscopic parameters. It was established in the early 1970s and is used by various computer codes to predict and simulate the transmission and emission of light in gaseous media (with an emphasis on terrestrial and planetary atmospheres). The HITRAN compilation is composed of five major components: the line-by-line spectroscopic parameters required for high-resolution radiative-transfer codes, experimental infrared absorption cross-sections (for molecules where it is not yet feasible for representation in a line-by-line form), collision-induced absorption data, aerosol indices of refraction, and general tables (including partition sums) that apply globally to the data. This paper describes the contents of the 2020 quadrennial edition of HITRAN. The HITRAN2020 edition takes advantage of recent experimental and theoretical data that were meticulously validated, in particular, against laboratory and atmospheric spectra. The new edition replaces the previous HITRAN edition of 2016 (including its updates during the intervening years).
All five components of HITRAN have undergone major updates. In particular, the extent of the updates in the HITRAN2020 edition range from updating a few lines of specific molecules to complete replacements of the lists, and also the introduction of additional isotopologues and new (to HITRAN) molecules: SO, CH3F, GeH4, CS2, CH3I and NF3. Many new vibrational bands were added, extending the spectral coverage and completeness of the line lists. Also, the accuracy of the parameters for major atmospheric absorbers has been increased substantially, often featuring sub-percent uncertainties. Broadening parameters associated with the ambient pressure of water vapor were introduced to HITRAN for the first time and are now available for several molecules.
The HITRAN2020 edition continues to take advantage of the relational structure and efficient interface available at www.hitran.org and the HITRAN Application Programming Interface (HAPI). The functionality of both tools has been extended for the new edition
Measurements of , , , , and production in 120 GeV/ p + C interactions
This paper presents multiplicity measurements of charged hadrons produced in
120 GeV/ proton-carbon interactions. The measurements were made using data
collected at the NA61/SHINE experiment during two different data-taking
periods, with increased phase space coverage in the second configuration due to
the addition of new subdetectors. Particle identification via was
employed to obtain double-differential production multiplicities of ,
, , , and . These measurements are presented as a
function of laboratory momentum in intervals of laboratory polar angle covering
the range from 0 to 450 mrad. They provide crucial inputs for current and
future long-baseline neutrino experiments, where they are used to estimate the
initial neutrino flux
Measurements of , , and spectra in Ar+Sc collisions at 13 to 150 GeV/
The NA61/SHINE experiment at the CERN Super Proton Synchrotron studies the
onset of deconfinement in strongly interacting matter through a beam energy
scan of particle production in collisions of nuclei of varied sizes. This paper
presents results on inclusive double-differential spectra, transverse momentum
and rapidity distributions and mean multiplicities of , ,
and produced in Ar+Sc collisions at beam momenta of
13, 19, 30, 40, 75 and 150 GeV/. The analysis uses the 10%
most central collisions, where the observed forward energy defines centrality.
The energy dependence of the / ratios as well as of inverse
slope parameters of the transverse mass distributions are placed in
between those found in inelastic + and central Pb+Pb collisions. The
results obtained here establish a system-size dependence of hadron production
properties that so far cannot be explained either within statistical (SMES,
HRG) or dynamical (EPOS, UrQMD, PHSD, SMASH) models
meson production in inelastic p+p interactions at 31, 40 and 80 GeV/c beam momentum measured by NA61/SHINE at the CERN SPS
Measurements of meson production via its decay mode
in inelastic interactions at incident projectile momenta of 31,
40 and 80 GeV/ ( and GeV, respectively) are
presented. The data were recorded by the NA61/SHINE spectrometer at the CERN
Super Proton Synchrotron. Double-differential distributions were obtained in
transverse momentum and rapidity. The mean multiplicities of mesons
were determined to be at
31 GeV/, at 40
GeV/ and at 80
GeV/. The results on production are compared with model
calculations (Epos1.99, SMASH 2.0 and PHSD) as well as with published data from
other experiments.Comment: arXiv admin note: substantial text overlap with arXiv:2106.0753
meson production in inelastic p+p interactions at 40 and 80 beam momenta measured by NA61/SHINE at the CERN SPS
Measurements of K∗(892)0 resonance production via its K+π− decay mode in inelastic p+p collisions at beam momenta 40 and 80 GeV /c (sNN−−−−√=8.8 and 12.3 GeV ) are presented. The data were recorded by the NA61/SHINE hadron spectrometer at the CERN Super Proton Synchrotron. The template method was used to extract the K∗(892)0 signal. Transverse momentum and rapidity spectra were obtained. The mean multiplicities of K∗(892)0 mesons were found to be (35.1±1.3(stat)±3.6(sys))⋅10−3 at 40 GeV /c and (58.3±1.9(stat)±4.9(sys))⋅10−3 at 80 GeV /c. The NA61/SHINE results are compared with the Epos1.99 and Hadron Resonance Gas models as well as with world data. The transverse mass spectra of K∗(892)0 mesons and other particles previously reported by NA61/SHINE were fitted within the Blast-Wave model. The transverse flow velocities are close to 0.1–0.2 of the speed of light and are significantly smaller than the ones determined in heavy nucleus-nucleus interactions at the same beam momenta
Measurements of K, Λ , and production in 120 GeV / c p + C interactions
This paper presents multiplicity measurements of K0S, Λ, and ¯Λ produced in 120 GeV/c proton-carbon interactions. The measurements were made using data collected at the NA61/SHINE experiment during two different periods. Decays of these neutral hadrons impact the measured π+, π−, p and ¯p multiplicities in the 120 GeV/c proton-carbon reaction, which are crucial inputs for long-baseline neutrino experiment predictions of neutrino beam flux. The double-differential multiplicities presented here will be used to more precisely measure charged-hadron multiplicities in this reaction, and to reweight neutral hadron production in neutrino beam Monte Carlo simulations
Measurement of Hadron Production in -C Interactions at 158 and 350 GeV/c with NA61/SHINE at the CERN SPS
We present a measurement of the momentum spectra of , K,
p, , and K produced in interactions of
negatively charged pions with carbon nuclei at beam momenta of 158 and 350
GeV/c. The total production cross sections are measured as well. The data were
collected with the large-acceptance spectrometer of the fixed target experiment
NA61/SHINE at the CERN SPS. The obtained double-differential - spectra
provide a unique reference data set with unprecedented precision and large
phase-space coverage to tune models used for the simulation of particle
production in extensive air showers in which pions are the most numerous
projectiles