arXiv subjects

K. Pohl

Publications and source records attributed to K. Pohl.

4 recordsLinked to original sources

arXiv2026

Dark photon searches in the photon channel

Spectral shape differences between photons produced in $\pi^0\to\gamma+\gamma$ and $\pi^0\to\gamma+A_D$ may provide a new avenue for dark photon searches. Assuming 70 $\mu$m thick tungsten foils separated by 200 $\mu$m and a 1 GeV proton beam, we developed a GEANT4 model to estimate photon production and detection including background. Our results demonstrate that multiple campaign runs with a 10-50 $\mu$A beam could probe previously unexplored regions of parameter space in models where the dark photon has predominantly invisible decays. The results are highly model independent.

hep-ph↗

arXiv2018

Classification of solvable Leibniz algebras with abelian nilradical and $k-1$ dimensional extension

This work is devoted to the classification of solvable Leibniz algebras with an abelian nilradical. We consider $k-1$ dimensional extension of $k$-dimensional abelian algebras and classify all $2k-1$-dimensional solvable Leibniz algebras with an abelian nilradical of dimension $k$.

math.RA↗

arXiv2008

Band structure effects on the Be(0001) acoustic-surface-plasmon energy dispersion

We report first-principles calculations of acoustic surface plasmons on the (0001) surface of Be, as obtained in the random-phase approximation of many-body theory. The energy dispersion of these collective excitations has been obtained along two symmetry directions. Our results show a considerable anisotropy of acoustic surface plasmons, and underline the capability of experimental measurements of these plasmons to {\it map} the electron-hole excitation spectrum of the quasi two-dimensional Shockley surface state band that is present on the Be(0001) surface.

cond-mat.mtrl-sci↗

arXiv2006

Structural determination of a low-symmetry surface by low-energy electron diffraction and ab initio calculations: Bi(110)

The surface structure of Bi(110) has been investigated by low-energy electron diffraction (LEED) intensity analysis and by first-principles calculations. Diffraction patterns at a sample temperature of 110 K and normal incidence reveal a bulk truncated (1$\times$1) surface without indication of any structural reconstruction despite the presence of dangling bonds on the surface layer. Good agreement is obtained between the calculated and measured diffraction intensities for this complex, low-symmetry surface containing only one mirror-plane symmetry element. No significant interlayer spacing relaxations are found. The Debye temperature for the surface layer is found to be lower than in the bulk, which is indicative of larger vibrational atomic amplitudes at the surface. Meanwhile, the second layer shows a Debye temperature close to the bulk value. The experimental results for the relaxations agree well with those of our first-principles calculation.

cond-mat.other↗