arXiv subjects

V. Verhoeven

Publications and source records attributed to V. Verhoeven.

5 recordsLinked to original sources

arXiv2026

Proposal for the first measurement of antiproton polarization in proton-nucleus interactions

Spin dependent phenomena in inclusive hadron production have been extensively investigated, yet their microscopic origin and universality across different hadrons are still not fully understood. In particular, it is presently unknown whether antiprotons produced in unpolarized hadronic collisions can acquire a transverse polarization as a result of spin dependent $\bar{p}N$ interactions and nonperturbative hadronization mechanisms. Establishing the presence or absence of such an effect would provide new empirical constraints on the spin structure of the antinucleon-nucleon interaction, which is only weakly constrained by existing data. In this work, we investigate the experimental feasibility of a first dedicated measurement of the transverse polarization of antiprotons produced in proton-nucleus collisions. The polarization is accessed through the left-right asymmetry in elastic $\bar{p}p$ scattering in the Coulomb Nuclear Interference region. Based on detailed Monte Carlo simulations of the proposed experimental setup at the European Organization for Nuclear Research (CERN), we estimate the statistical sensitivity required to detect a certain degree of polarization.

hep-ex↗

arXiv2025

P371 Experiment at CERN -- quest for polarized antiprotons

Polarization effects in the production of antiprotons at the CERN PS beam line T11 at 3.5 GeV/c have been investigated within the P371 experiment. These effects, if found to be significant could provide a simple method to generate polarized antiproton beams with existing facilities. First precursor measurements were carried out by the P349 collaboration, though the available statistics were insufficient for a quantitative conclusion. With an upgraded detector setup and extended beam time, the experiment aims at determining whether a measurable degree of antiproton polarization exists.

hep-ex↗

arXiv2023

A Universal Method to Generate Hyperpolarisation in Beams and Samples

Sizable hyperpolarisation, i.e. an imbalance of the occupation numbers of nuclear spins in a sample deviating from thermal equilibrium, is needed in various fields of science. For example, hyperpolarised tracers are utilised in magnetic resonance imaging in medicine (MRI) and polarised beams and targets are employed in nuclear physics to study the spin dependence of nuclear forces. Here we show that the quantum interference of transitions induced by radio-wave pumping with longitudinal and radial pulses are able to produce large polarisations at small magnetic fields. This method is easier than established methods, theoretically understood and experimentally proven for beams of metastable hydrogen atoms in the keV energy range. It should also work for a variety of samples at rest. Thus, this technique opens the door for a new generation of polarised tracers, possibly low-field MRI with better spatial resolution or the production of polarised fuel to increase the efficiency of fusion reactors by manipulating the involved cross sections.

physics.atom-ph↗

arXiv2020

Exploiting the Planck-Einstein Relation

The origin of quantum physics was the discovery of the base unit of electromagnetic action $h$ by Max Planck in 1900 when he analyzed the experimental results of the black body radiation. This permitted Albert Einstein a few years later to explain the photoelectric effect by the absorption of photons with an energy of $E = h \cdot f$. We exploit the Planck-Einstein relation in a new type of fundamental spectroscopic measurements of direct transitions between two states with energy differences of about 10 neV and induced frequencies of a few MHz. Employing a Lamb-shift polarimeter and a Sona transition unit, featuring a relatively simple magnetic field configuration of two opposing solenoidal coils, we were able to determine $f$ and measure $E$ independently. Only resonances corresponding to integer multiples of Planck's constant $h$ were observed in our setup, which can very well be explained quantitatively by the Schrödinger equation. This new method beautifully demonstrates the quantization in the micro-cosmos and allows one to measure the hyperfine splitting energies between the substates with $F=1$ and $m_F = -1, 0, +1$ of metastable hydrogen atoms as function of a magnetic field and, thus, to investigate the influence of QED corrections on the Breit-Rabi diagram.

physics.atom-ph↗

arXiv2020

Production of HD Molecules in Definite Hyperfine Substates

Polarized atomic beam sources have been in operation since many years to produce either nuclear polarized atomic hydrogen or deuterium beams. In recent experiments such a source was used to polarize both isotopes independently at the same time. By recombination of the atoms, HD molecules with all possible nuclear spin combinations can be created. Those spin isomers are useful for further applications like precision spectroscopy, as polarized targets for laser-particle acceleration, polarized fuel for fusion reactors or as an option for future measurements of electric dipole moments.

physics.atom-ph↗