Speaker
Description
Four yields of strange hadrons ($\phi$ and $\bar{K}^*(892)^0$ mesons, $\Xi$ and $\Xi^-$ baryons) emitted from p+p collisions at $\sqrt{s}$ = 17.3 GeV have been recently measured by the NA61/SHINE collaboration 1. These results prompted the creation of a unified set of particle yields, combining the data from NA49 and NA61/SHINE in a consistent manner (instead of treating the measurements separately [2,3]).
We used the Thermal-FIST statistical hadronization code with the canonical ensemble required for either hadrons with open strangeness only, or all the particles [4]. With physically unjustified omission of the $\phi$ meson yield, a satisfactory fit quality is obtained. However, all the particle yields including the $\phi$ meson might be reproduced with $\chi^2$/NDF $\approx$ 1.5, if the volume of strangeness production is above that for non-strange particles. Newest NA61/SHINE results on $\Xi^0$(1530) and $\bar{\Xi}^0$(1530) baryons and $\mathrm{K}^0_S$ meson [5] are also discussed.
The larger volume of strangeness emission zone in pp interactions might be revealed via HBT investigations of production volume of strange and non-strange particles. The uncertainties of existing measurements spread over energies above SPS do not allow to verify this conjecture. A precise femtoscopic study is therefore welcome.
1 A. Aduszkiewicz et al. (NA61/SHINE Collaboration) Eur. Phys. J. C80, 199 (2020); ibid. p. 460; ibid. p. 833.
2 I. Kraus, J. Cleymans, H. Oeschler, K. Redlich, Phys. Rev. C 81, 024903 (2010).
3 V.V. Begun, V. Vovchenko, M.I. Gorenstein, H. Stoecker, Phys. Rev. C 98, 054909 (2018).
[4] T. Matulewicz, K. Piasecki, J. Phys. G: Nucl. Part. Phys. 48, 085004 (2021).
doi:10.1088/1361-6471/abfdd7
[5] NA61/SHINE Collaboration: arXiv:2105.09144, arXiv:2106.07535
