arXiv subjects

Mirco Christmann

Publications and source records attributed to Mirco Christmann.

4 recordsLinked to original sources

arXiv2026

Precise measurement of the $\Lambda$-binding energy difference between $^3_\Lambda$H and $^4_\Lambda$H via decay-pion spectroscopy at MAMI

We performed high-precision decay-pion spectroscopy of light $\Lambda$ hypernuclei at the Mainz Microtron (MAMI) using the A1 spectrometer facility. By measuring the monochromatic $\pi^-$ momentum from the two-body weak decay $^3_\Lambda\mathrm{H} \to {}^3\mathrm{He} + \pi^-$ and referencing it to the $^4_\Lambda\mathrm{H} \to {}^4\mathrm{He} + \pi^-$ decay, we determined the $\Lambda$ binding energy of $^3_\Lambda\mathrm{H}$ with unprecedented accuracy. The obtained value, $B_\Lambda(^3_\Lambda\mathrm{H}) = 0.523 \pm 0.013~(\mathrm{stat.}) \pm 0.075~(\mathrm{syst.})$~MeV, is consistent with the STAR result, but indicates a significantly deeper binding than inferred from earlier measurements. This result implies a stronger $\Lambda$-deuteron interaction and provides stringent constraints on hyperon-nucleon interactions.

nucl-ex↗

arXiv2025

Measurement of $\rm ^{6}H$ ground state energy in an electron scattering experiment at MAMI-A1

For the first time the neutron-rich hydrogen isotope $\rm ^{6}H$ was produced in an electron scattering experiment in the reaction $\rm ^{7}Li(e,~e'p\pi^{+})^{6}H$ using the spectrometer facility of the A1 Collaboration at the Mainz Microtron accelerator. By measuring the triple coincidence between the scattered electron, the produced proton, and $\pi^{+}$, the missing mass spectrum of $\rm ^{6}H$ was obtained. A clear peak above $^3$H+n+n+n energy threshold was seen resulting in a ground state energy of $\rm ^{6}H$ at $2.3\pm0.5({\rm stat.})\pm0.4({\rm syst.})$ MeV with a width of $1.9\pm1.0({\rm stat.})\pm0.4({\rm syst.})$ MeV. This work challenges the understandings of multi-nucleon interactions and presents a new method to study light neutron-rich nuclei with electron scattering experiments.

nucl-ex↗

arXiv2019

Dark Matter at the Intensity Frontier: the new MESA electron accelerator facility

Dark Matter is being searched with a variety of methods, each of which tackles this challenge focusing on different kinds of particles, masses and couplings. Here we describe Dark Matter searches conducted with accelerators and fixed targets. In particular, we highlight the contribution of the experiments being built at the new Mainz Energy-recovery Superconducting Accelerator (MESA) facility. MESA will provide intense electron beams for hadron and nuclear physics, as well as for Dark Matter searches with competitive sensitivities.

hep-ex↗

arXiv2018

Search for light dark matter with the MESA accelerator

At the Institute for Nuclear Physics of the Johannes Gutenberg University in Mainz, the MESA facility is currently being constructed. At its core there is a new superconducting energy-recovery linac which will provide intense electron beams for precision experiments in subatomic physics. An important part of the MESA physics program consists in the search for a "dark sector" which is a candidate explanation for the longstanding dark matter problem. This report will highlight the MESA dark sector program, and in particular two experiments will be described. The first one, MAGIX, is a two-spectrometer setup employing an internal gas-jet target installed on a recirculation arc of MESA. The second one is a beam-dump experiment for directly detecting dark matter particles. The experiments are in the R\&D phase and the current status and future prospects will be presented.

hep-ex↗