Measurements of Ξ(1530)0{\Xi \left( 1530\right) ^{0}} and Ξ‾(1530)0{\overline{\Xi }\left( 1530\right) ^{0}} production in proton–proton interactions at sNN\sqrt{s_{NN}} = 17.3 = 17.3 GeV \text{ GeV } in the NA61/SHINE experiment

Double-differential yields of $\Xi\left(1530\right)^{0}$ and $\overline{\Xi}\left(1530\right)^{0}$ resonances produced in \pp interactions were measured at a laboratory beam momentum of 158~\GeVc. This measurement is the first of its kind in \pp interactions below LHC energies. It was performed at the CERN SPS by the \NASixtyOne collaboration. Double-differential distributions in rapidity and transverse momentum were obtained from a sample of 26$\cdot$10$^6$ inelastic events. The spectra are extrapolated to full phase space resulting in mean multiplicity of $\Xi\left(1530\right)^{0}$ (6.73 $\pm$ 0.25 $\pm$ 0.67)$\times10^{-4}$ and $\overline{\Xi}\left(1530\right)^{0}$ (2.71 $\pm$ 0.18 $\pm$ 0.18)$\times10^{-4}$. The rapidity and transverse momentum spectra and mean multiplicities were compared to predictions of string-hadronic and statistical model calculations

Measurements of Ξ−{\Xi }{^-} and Ξ‾+\overline{\Xi }{^+} production in proton–proton interactions at sNN\sqrt{s_{NN}}=17.3 GeV = 17.3 GeV in the NA61/SHINE experiment

International audienceThe production of $\Xi (1321)^{-}$ and $\overline{\Xi }(1321)^{+}$ hyperons in inelastic p+p interactions is studied in a fixed target experiment at a beam momentum of 158 $\hbox {Ge}\hbox {V}\!/\!c$. Double differential distributions in rapidity ${y}$ and transverse momentum $p_{T}$ are obtained from a sample of 33M inelastic events. They allow to extrapolate the spectra to full phase space and to determine the mean multiplicity of both ${\Xi }{^-}$ and $\overline{\Xi }{^+}$. The rapidity and transverse momentum spectra are compared to transport model predictions. The ${\Xi }{^-}$ mean multiplicity in inelastic p+p interactions at 158 $\hbox {Ge}\hbox {V}\!/\!c$ is used to quantify the strangeness enhancement in A+A collisions at the same centre-of-mass energy per nucleon pair

Measurements of total production cross sections for π+\pi^{+}+C, π+\pi^{+}+Al, K+K^{+}+C, and K+K^{+}+Al at 60 GeV/c and π+\pi^{+}+C and π+\pi^{+}+Al at 31 GeV/c

International audienceThis paper presents several measurements of total production cross sections and total inelastic cross sections for the following reactions: π++C, π++Al, K++C, K++Al at 60  GeV/c, π++C and π++Al at 31  GeV/c. The measurements were made using the NA61/SPS Heavy Ion and Neutrino Experiment spectrometer at the CERN Super Proton Synchrotron (SPS). Comparisons with previous measurements are given and good agreement is seen. These interaction cross sections measurements are a key ingredient for neutrino flux prediction from the reinteractions of secondary hadrons in current and future accelerator-based long-baseline neutrino experiments

Measurements of π±, K±, p and p¯ spectra in 7Be+9Be collisions at beam momenta from 19A to 150A GeV/c with the NA61/SHINE spectrometer at the CERN SPS

The NA61/SHINE experiment at the CERN Super Proton Synchrotron (SPS) studies the onset of deconf inement in hadron matter by a scan of particle production in collisions of nuclei with various sizes at a set of energies covering the SPS energy range. This paper presents results on inclusive double-differential spectra, transverse momentumandrapidity distributions and mean multiplicities of π±, K±, p and ¯p produced in the 20% most central 7Be+9Be collisions at beam momenta of 19A,30A,40A,75A and 150A GeV/c. The energy dependence of the K±/π± ratios as well as of inverse slope parameters of the K± transverse mass distributions are close to those found in inelastic p+p reactions. The new results are compared to the world data on p+p and Pb+Pb collisions as well as to predictions of the Epos, Urqmd, Ampt, Phsd and Smash models

Excess of charged over neutral KK meson production in high-energy collisions of atomic nuclei

Collisions of atomic nuclei at relativistic velocities produce new particles, predominantly mesons containing one valence quark and one valence anti-quark. These particles are produced in strong interactions, which preserve an approximate symmetry between up ($u$) and down ($d$) quarks. In the case of $K$ meson production, if this symmetry were exact, it would result in equal numbers of charged ($K^+$ and $K^-$) and neutral ($K^0$ and $\overline K^0$) mesons in the final state. In this Letter, we report a measurement of the relative abundance of charged over neutral $K$ meson production in collisions of argon and scandium nuclei at a center-of-mass energy of 11.9~GeV per nucleon pair. We find that production of $\mathit{K^+}$ and $\mathit{K^-}$ mesons at mid-rapidity displays a significant excess of $(23.3\pm 5.7)\%$ relative to that of the neutral $K$ mesons. The origin of this unexpected excess remains to be elucidated.Collisions of atomic nuclei at relativistic velocities produce new particles, predominantly mesons containing one valence quark and one valence anti-quark. These particles are produced in strong interactions, which preserve an approximate symmetry between up ($u$) and down ($d$) quarks. In the case of $K$ meson production, if this symmetry were exact, it would result in equal numbers of charged ($K^+$ and $K^-$) and neutral ($K^0$ and $\overline{K}$$^0$) mesons in the final state. In this Letter, we report a measurement of the relative abundance of charged over neutral $K$ meson production in collisions of argon and scandium nuclei at a center-of-mass energy of 11.9~GeV per nucleon pair. We find that production of $K^+$ and $K^-$ mesons at mid-rapidity displays a significant excess of $(23.3\pm 5.7)\%$ relative to that of the neutral $K$ mesons. The origin of this unexpected excess remains to be elucidated