Oscillations and potentials of mesons and baryons

In the following, the oscillations and potentials of mesons and baryons are examined and analyzed in detail. The oscillations result from a simple formula that describes the resonance energy at which the corresponding particle can absorb energy and thus appear. The potentials describe three mechanisms that describe the fine splitting of the masses of the elementary particles. These potentials can be read off and derived from the experimentally determined masses of the elementary particles as coefficients. The three mechanisms are internal mass charge binding energy, external mass charge binding energy, and Coulomb interaction.

Dielectric Confinement and Exciton Fine Structure in Lead Halide Perovskite Nanoplatelets

Owing to their flexible chemical synthesis and the ability to shape nanostructures, lead halide perovskites have emerged as high potential materials for optoelectronic devices. Here, we investigate the excitonic band edge states and their energies levels in colloidal inorganic lead halide nanoplatelets, particularly the influence of dielectric effects, in a thin quasi-2D system. We use a model including band offset and dielectric confinements in the presence of Coulomb interaction. Short- and long-range contributions, modified by dielectric effects, are also derived, leading to a full modelization of the exciton fine structure, in cubic, tetragonal and orthorhombic phases. The fine splitting structure, including dark and bright excitonic states, is discussed and compared to recent experimental results, showing the importance of both confinement and dielectric contributions.

Atomic Data Needs in Astrophysics: The Galactic Center “Scandium Mystery”

Investigating the Galactic center offers unique insights into the buildup and history of our Galaxy and is a stepping stone to understand galaxies in a larger context. It is reasonable to expect that the stars found in the Galactic center might have a different composition compared to stars found in the local neighborhood around the Sun. It is therefore quite exciting when recently there were reports of unusual neutral scandium, yttrium, and vanadium abundances found in the Galactic center stars, compared to local neighborhood stars. To explain the scandium abundances in the Galactic center, we turn to recent laboratory measurements and theoretical calculations done on the atomic oscillator strengths of neutral scandium lines in the near infrared. We combine these with measurements of the hyper fine splitting of neutral scandium. We show how these results can be used to explain the reported unusual scandium abundances and conclude that in this respect, the environment of the Galactic center is not that different from the environment in the local neighborhood around the sun.

Stellar population astrophysics (SPA) with the TNG

Context. In the advent of new infrared high-resolution spectrometers, accurate and precise atomic data in the infrared are urgently needed. Identifications, wavelengths, strengths, broadening, and hyper-fine splitting parameters of stellar lines in the near-infrared are in many cases not accurate enough to model observed spectra, and in other cases, these parameters do not even exist. Some stellar features are unidentified. Aims. The aim with this work is to identify a spectral feature at λvac = 1063.891 nm or λair = 1063.600 nm that is visible in spectra of stars of different spectral types that are observed with the GIANO-B spectrometer. Methods. The search for spectral lines to match the unidentified feature in line lists from standard atomic databases was not successful. However, by investigating the original published laboratory data, we were able to identify the feature and solve the problem. To confirm its identification, we modelled the presumed stellar line in the solar intensity spectrum and found an excellent match. Results. We find that the observed spectral feature is a stellar line originating from the 4s′–4p′ transition in S I, and that the reason for its absence in atomic line databases is a neglected air-to-vacuum correction in the original laboratory measurements from 1967 for this line only. From interpolation we determine the laboratory wavelength of the S I line to be λvac = 1063.8908 nm or λair = 1063.5993 nm, and the excitation energy of the upper level to be 9.74978 eV.

CMS results on collectivity in PbPb collisions at √sNN = 2.76 and 5.02 TeV

Nonlinear response coeffcients of higher-order vn anisotropy harmonics for charged particles, as a function of transverse momentum (pT) and collision centrality, are measured in PbPb collisions at √sNN = 2.76 and 5.02 TeV. The nonlinear response coefficients are obtained using vn harmonics measured with respect to their own plane and the mixed harmonics. Using a fine splitting between v2{4} and v2{6} cumulants, the centrality dependence of the elliptic flow skewness is measured at 5.02 TeV PbPb collisions. The CMS also measured the v2 and v3 anisotropy harmonics of charged particles and prompt D0 mesons at |y| ≤ 1 as a function of pT and centrality in PbPb data at √sNN = 5.02 TeV collected with the CMS detector. Prompt D0 mesons, formed from the c quarks produced via initial hard scatterings, are separated up to a high extent from nonprompt D0 mesons emerged from decays of b hadrons. The results indicate that the charm quarks interact strongly with the QGP medium. Comparisons between theoretical models and data provide new constraints on the initial-state conditions and the interaction between charm quarks and the QGP medium.