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Hjalmar Brunßen

Publications and source records attributed to Hjalmar Brunßen.

2 recordsLinked to original sources

Hadronization into Nuclei: Does Size Matter?

We investigate an extension of the statistical hadronization model (SHM) that takes (hyper)nucleus sizes into account. The spatial extent of nuclear wave functions relative to the fireball volume is used to calculate a size correction, which describes the suppression with respect to a point-like treatment of the (hyper)nucleus at hadronization. For several species of light nuclei (d, ${}^{3}\mathrm{H}$, ${}^{3}\mathrm{He}$) and for the hypernucleus ${}^{3}_Λ\mathrm{H}$, the predicted effects of the size correction on SHM yields are compared to yield measurements in pp, p-Pb, and Pb-Pb collisions in the ALICE experiment. The experimental data suggest that this size correction, based on applying final-state wave functions at chemical freeze-out, does not give a consistent description of (hyper)nucleus production in nuclear and hadronic collisions. By contrast, the SHM without a nuclear-size correction provides a substantially better description of the data. This result lends further support to the interpretation that such nuclear states are formed from initially compact (multi-quark) configurations which after hadronization expand to their final-state wave functions.

nucl-th↗

Transverse dynamics of charmed hadrons in ultra-relativistic nuclear collisions

Transverse momentum $p_{\rm T}$ spectra and anisotropic flow distributions are studied for charmonia and charmed hadrons produced in Pb-Pb collisions and measured with the ALICE detector at the CERN Large Hadron Collider (LHC). The investigations are performed within the framework of the Statistical Hadronization Model with the transverse dynamics evaluated using predictions from relativistic viscous hydrodynamics as implemented in the computer codes MUSIC and FluiduM. With this essentially parameter-free approach, mostly good agreement is obtained for $p_{\rm T}$ spectra in the range $p_{\rm T}$ $< 10$ GeV/c. The calculations suggest a hardening of the ${\rm J}/ψ$ $p_{\rm T}$ distribution for more central collisions while the data show the opposite trend. The observed wide distribution in $p_{\rm T}$ of anisotropic flow coefficients v$_2$ and v$_3$ for charmonia is also well reproduced, while their magnitude is generally somewhat over predicted. This finding may be connected to a difference in spatial distribution between light and charmed hadrons due to a different diffusion of light and heavy quarks in the hot fireball.

hep-ph↗