Speaker
Description
The short-range component and density dependence of the ΛN interaction are crucial for understanding hyperons in neutron stars, yet remain poorly constrained experimentally. While the long-range part is limited by the ⁵ΛHe binding energy, short-range uncertainties persist. Large-source-size AA collisions, such as STAR-BESII, are mainly sensitive to the long-range region, whereas the small-source-size pA collisions in the J-PARC E88 experiment are highly sensitive to the short-range part, making them a powerful probe.
E88’s primary goal is to measure the in-medium modification of the φ meson via e⁺e⁻ and K⁺K⁻ pair measurements. Using the hadron detection system, we will also conduct α–Λ femtoscopy as a byproduct. The α particle’s spin and isospin of zero, along with its twice-normal nuclear density, allow direct constraints on the density dependence of the ΛN interaction. At √sNN ≈ 10 GeV, α yields in pA collisions are 100–1000 times higher than in high-energy collisions, enabling high-statistics measurements.
Future plans at J-PARC-HI include high-statistics α–hyperon femtoscopy and polarized-proton femtoscopy for partial-wave analysis. This presentation will outline the femtoscopy program at J-PARC, highlighting the complementary roles of E88 (short-range) and J-PARC-HI (long-range) measurements.