arXiv subjects

T. Reichert

Publications and source records attributed to T. Reichert.

8 recordsLinked to original sources

arXiv2025

Hadron Physics Opportunities at FAIR

This White Paper outlines a coordinated, decade-spanning programme of hadron and QCD studies anchored at the GSI/FAIR accelerator complex. Profiting from intense deuteron, proton and pion beams coupled with high-rate capable detectors and an international theory effort, the initiative addresses fundamental questions related to the strong interaction featuring confinement and dynamical mass generation. This includes our understanding of hadron-hadron interactions and the composition of hadrons through mapping the baryon and meson spectra, including exotic states, and quantifying hadron structure. This interdisciplinary research connects topics in the fields of nuclear, heavy-ion, and (nuclear) astro (particle) physics, linking, for example, terrestrial data to constraints on neutron star structure. A phased roadmap with SIS100 accelerator start-up and envisaged detector upgrades will yield precision cross sections, transition form factors, in-medium spectral functions, and validated theory inputs. Synergies with external programmes at international accelerator facilities worldwide are anticipated. The programme is expected to deliver decisive advances in our understanding of non-perturbative (strong) QCD and astrophysics, and high-rate detector and data-science technology.

hep-ex↗

arXiv2024

Production of double strange hypernuclei and exotic nuclei in central Au+Au collisions at $\sqrt{s_{NN}}$=3 GeV

We extend the theoretical approach which includes the dynamical and statistical stages for the description of the nucleosynthesis in central collisions of relativistic ions. Previously, this approach was successfully applied to describe experimental data on both normal nuclei and single strange hypernuclei production in the GSI and RHIC-BES energy range. We predict the multiplicities of double strange hypernuclei up to $^4_{\Lambda \Lambda}$H and further intermediate mass nuclei up to $^8$Be for Au+Au central collisions at $\sqrt{s_{NN}}$=3 GeV, recently explored by the STAR experiments. These new nuclei can be identified by the measurement of the correlated particles coming after their decay. Such observations are a crucial test for the nucleosynthesis mechanism.

nucl-th↗

arXiv2024

Nucleation of baryons in relativistic hadron-nucleus collisions

We suggest a new theoretical method to describe the baryon clusterization of nuclei in hadron-nucleus reactions. As an example we have explored the nuclei production in $\pi^-+C$ and $\pi^-+W$ collisions at p$_{lab}$=1.7 GeV by using the hybrid approach consisting of the Ultra Relativistic Quantum Dynamics Model (UrQMD) and the Statistical Multifragmentation Model (SMM). The UrQMD describes the production of new baryons, and the propagation toward the subnuclear densities with the fluctuations leading to the formation of excited baryonic clusters. The SMM describes the production of final nuclei and hypernuclei after interaction of baryons inside these clusters. We demonstrate the transverse momenta, rapidity, mass distributions and excitation energies of both primary clusters and final nuclei (including hypernuclei). The results of the UrQMD and UrQMD+SMM model calculations for different clusterization parameters are compared with the available HADES experimental data on baryon production, providing a very promising window for future research on nuclei and hypernuclei formation in these reactions.

nucl-th↗

arXiv2023

Nucleosynthesis of light nuclei and hypernuclei in central Au+Au collisions at $\sqrt{s_{NN}}$=3 GeV

We analyze the experimental data on nuclei and hypernuclei yields recently obtained by the STAR collaboration. The hybrid dynamical and statistical approaches which have been developed previously are able to describe the experimental data reasonably. We discuss the intriguing difference between the yields of normal nuclei and hypernuclei which may be related to the properties of hypermatter at subnuclear densities. Most importantly new (hyper-)nuclei could be detected via particle correlations, and such measurements are relevant to pin down the production mechanism.

nucl-th↗

arXiv2021

Longitudinal charge distribution measurement of non-relativistic ion beams using coherent transition radiation

Longitudinal charge profile measurements or bunch shape measurements is a challenge for temporally short non-relativistic bunches. The field profile has a larger longitudinal extent compared to the charge profile for such beams. This affects the ability of field sensing devices such as phase pick-ups or wall current monitors to measure charge distribution. Here we evaluate the feasibility for usage of coherent transition and diffraction radiation from non-relativistic beams for bunch shape measurements.

physics.ins-det↗

arXiv2021

Transition radiation based transverse beam diagnostics for non relativistic ion beams

The usage of optical transition radiation for profile monitoring of relativistic electron beams is well known. This report presents the case for beam diagnostic application of optical transition radiation for non-relativistic ion beams. The angular distribution of the transition radiation emitted from few target materials for ion beam irradiation is shown. In addition to expected linearly polarized transition radiation in the plane of observation, a large amount (roughly factor 20) of unpolarized radiation is observed towards grazing angles. The unpolarized radiation has the characteristics of transition radiation and is understood as the transition radiation generated from a "strongly" rough target surface. This increase in amount of radiation towards the detector can be used advantageously towards transverse profile measurements and potentially other beam parameters. Further systematic effects such as the dependence of photon yield on beam current, comparison of the measured transverse profiles with Secondary electron emission based grid (SEM grid), target heating etc. are also discussed.

physics.ins-det↗

arXiv2018

Coexistence of weak and strong coupling with a quantum dot in a photonic molecule

We study the emission from a molecular photonic cavity formed by two proximal photonic crystal defect cavities containing a small number (<3) of In(Ga)As quantum dots. Under strong excitation we observe photoluminescence from the bonding and antibonding modes in excellent agreement with expectations from numerical simulations. Power dependent measurements reveal an unexpected peak, emerging at an energy between the bonding and antibonding modes of the molecule. Temperature dependent measurements show that this unexpected feature is photonic in origin. Time-resolved measurements show the emergent peak exhibits a lifetime $τ_M=0.75 \, \pm 0.1 \, ns $, similar to both bonding and antibonding coupled modes. Comparison of experimental results with theoretical expectations reveal that this new feature arises from a coexistence of weak- and strong-coupling, due to the molecule emitting in an environment whose configuration permits or, on the contrary, impedes its strong-coupling. This scenario is reproduced theoretically for our particular geometry with a master equation reduced to the key ingredients of its dynamics. Excellent qualitative agreement is obtained between experiment and theory, showing how solid-state cavity QED can reveal new regimes of light-matter interaction.

cond-mat.mes-hall↗

arXiv2016

A few-emitter solid-state multi-exciton laser

We report a combined experimental and theoretical study of non-conventional lasing from higher multi-exciton states of a few quantum dot-photonic crystal nanocavity. We show that the photon output is fed from saturable quantum emitters rather than a non-saturable background despite being rather insensitive to the spectral position of the mode. Although the exciton transitions of each quantum dot are detuned by up to $160$ cavity linewidths, we observe that strong excitation populates a multitude of closely spaced multi-exciton states, which partly overlap spectrally with the mode. The limited number of emitters is confirmed by a complete saturation of the mode intensity at strong pumping, providing sufficient gain to reach stimulated emission, whilst being accompanied by a distinct lasing threshold. Detailed second-order photon-correlation measurements unambiguously identify the transition to lasing for strong pumping and, most remarkably, reveal super-thermal photon bunching with $g^{(2)}(0)>2$ below lasing threshold. Based on our microscopic theory, a pump-rate dependent $β$-factor $β(P)$ is needed to describe the nanolaser and account for the interplay of multi-exciton transitions in the few-emitter gain medium. Moreover, we theoretically predict that the super-thermal bunching is related to dipole-anticorrelated multi-exciton recombination channels via sub- and super-radiant coupling below and above lasing threshold, respectively. Our results provide new insights into the microscopic light-matter-coupling of spatially separated emitters coupled to a common cavity mode and, thus, provides a complete understanding of stimulated emission in nanolasers with discrete emitters.

cond-mat.mes-hall↗