P. Semeniuk | Searcharxiv

arXiv2026

$K^{*}(892)^0$ production and the time between freeze-outs in $^{40}$Ar+$^{45}$Sc collisions by NA61/SHINE at the CERN SPS

The analysis of the production of strange $K^{*}(892)^0$ resonances allows us to better understand the temporal evolution of high-energy nucleus--nucleus collisions. In particular, the ratio of $K^{*}(892)^0$ to charged kaon yields is used to determine the time interval between chemical and kinetic freeze-outs. In this paper, the first measurements of $K^{*}(892)^0$ production in central $^{40}$Ar+$^{45}$Sc collisions at the CERN Super Proton Synchrotron are reported. They were performed by NA61/SHINE at collision center-of-mass energies per nucleon pair $\sqrt{s_\mathrm{NN}}$ = 8.8, 11.9, 16.8 GeV. The obtained $\langle K^{*}(892)^0 \rangle/\langle K^{+} \rangle $ and $\langle K^{*}(892)^0 \rangle/\langle K^{-} \rangle$ mean multiplicity ratios are compared with corresponding results in $p$+$p$ collisions, allowing for an estimate of the time interval between chemical and thermal freeze-outs in the $^{40}$Ar+$^{45}$Sc system. These are the first such results reported for $^{40}$Ar+$^{45}$Sc collisions.

nucl-ex↗

arXiv2025

Minimal material, maximum coverage: Silicon Tracking System for high-occupancy conditions

Silicon strip sensors have long been a reliable technology for particle detection. Here, we push the limits of silicon tracking detectors by targeting an unprecedentedly low material budget of 2%-7% $X_0$ in an 8-layer 4 m$^2$ detector designed for high-occupancy environments ($\leq$ 10 MHz/cm$^2$). To achieve this, we employ Double-Sided Double Metal (DSDM) silicon microstrip sensors, coupled with readout electronics capable of precise timing and energy measurements. These 320 $μ$m thick sensors, featuring $2\times 1024$ channels with a 58 $μ$m pitch, are connected via ultra-lightweight aluminium-polyimide microcables for signal transmission and integrated with a custom SMX readout ASIC, operating in free-streaming mode. This system enables the simultaneous measurement of time ($Δt \simeq 5$~ns) and charge deposition (0.1-100 fC), significantly enhancing the detector's capacity for high-precision track reconstruction in high-occupancy and harsh radiation field environments. The primary application of this technology is the Silicon Tracking System (STS) for the CBM experiment, with additional potential in projects like the J-PARC E16 experiment and future uses in medical physics, such as advanced imaging telescopes. In this contribution, we present the current status of CBM STS construction, with almost one-third of the modules produced and tested. We also discuss immediate applications and explore promising prospects in both scientific and medical fields.

physics.ins-det↗