Garchinger Maier-Leibnitz-Kolloquium: Unveiling the fundamental production mechanism of light nuclei using coalescence and femtoscopy

by Dr Maximilian Mahlein (Physik Department E12b, TUM)

Thursday 12 Jun 2025, 16:15 → 17:15 Europe/Berlin

Lecture Hall, ground floor (west) (LMU building, Am Coulombwall 1, campus Garching)

The formation of (anti)nuclei in high-energy collisions has attracted considerable interest in recent years. Two phenomenological models, the statistical hadronization model and the coalescence model, are both capable of describing the available data. However, it has not been possible to distinguish clearly between them based on experimental evidence. According to the coalescence model, nucleons form independently and then bind together after freeze-out if they are sufficiently close in phase-space. A recent advancement of the model is the Wigner function formalism, which allows the calculation of the coalescence probability based on the distance and relative momentum of the constituent nucleons, independently of the collision energy or system. The interest in explaining nuclear formation processes extends beyond standard model physics, with implications for indirect Dark Matter searches. Understanding the production mechanism of antinuclei is crucial for correctly interpreting any future measurement of antinuclear flux in space, as it would allow for the differentiation of the background originating from collisions between high-energy Cosmic Rays and the stationary Interstellar Medium. In this presentation, we show using femtoscopy that nuclear formation can only be explained by the coalescence model. In this presentation, we show through femtoscopy that nuclear formation is consistent only with the coalescence model. We present a detailed overview of the current state of the coalescence formalism, extending the analysis from deuterons to the more complex case of nuclei with mass number A=3. This represents a significant advancement, as previous efforts primarily focused on modeling the formation of simpler bound states, e.g., deuterons. The model is tested for the numerous pp collision data measured by ALICE. Our approach introduces a novel aspect by implementing this model into a purpose-built Monte Carlo generator called ToMCCA. This generator offers exceptional adaptability while maintaining superior performance compared to traditional general-purpose event generators.

Hybrid access via ZOOM:
https://lmu-munich.zoom.us/j/98457332925?pwd=TWc3V1JkSHpyOTBPQVlMelhuNnZ1dz09
Meeting ID: 984 5733 2925
Passcode: 979953

kolloquium-12-06-25.pdf