Publications

2026

• Measurement of $\Lambda$ Polarization in the $\pi^{-}p \to K^{0} \Lambda$ Reaction at $p_{\pi^{-}}=1.33$ GeV/$c$ toward a New $\Lambda p$ Scattering Experiment
  
  • Sakao T
  • Miwa K
  • Ahn J.K
  • Akazawa Y
  • Aramaki T
  • Ashikaga S
  • Callier S
  • Chiga N
  • Choi S.W
  • Ekawa H
  • Evtoukhovitch P
  • Fujioka N
  • Fujita M
  • Gogami T
  • Harada T
  • Hasegawa S
  • Hayakawa S.H
  • Honda R
  • Hoshino S
  • Hosomi K
  • Ichikawa M
  • Ichikawa Y
  • Ieiri M
  • Ikeda M
  • Imai K
  • Ishikawa Y
  • Ishimoto S
  • Jung W.S
  • Kajikawa S
  • Kanauchi H
  • Kanda H
  • Kitaoka T
  • Kang B.M
  • Kawai H
  • Kim S.H
  • Kobayashi K
  • Koike T
  • Matsuda K
  • Matsumoto Y
  • Nagao S
  • Nagatomi R
  • Nakada Y
  • Nakagawa M
  • Nakamura I
  • Nanamura T
  • Naruki M
  • Ozawa S
  • Raux L
  • Rogers T.G
  • Sakaguchi A
  • Sako H
  • Sato S
  • Shiozaki T
  • Shirotori K
  • Suzuki K.N
  • Suzuki S
  • Tabata M
  • Taille C.D.L
  • Takahashi H
  • Takahashi T
  • Takahashi T.N
  • Tamura H
  • Tanaka M
  • Tanida K
  • Tsamalaidze Z
  • Ukai M
  • Umetsu H
  • Wada S
  • Yamamoto T.O
  • Yoshida J
  • Yoshimura K
  PTEP, 2026, 2026 (1), pp.013D01. This paper presents high-precision experimental data of the polarization of the $\Lambda$ hyperon in the $\pi^{-}p \to K^{0} \Lambda$ reaction, measured in the angular range $0.6<\cos \theta ^{CM}_{K0}<1.0$ with a fine bin width of $d\cos \theta ^{CM}_{K0}=0.05$. The data were obtained from the J-PARC E40 experiment at the K1.8 beamline in the J-PARC Hadron Experimental Facility. The observed average polarization of $\Lambda$ in the range $0.60<\cos \theta ^{CM}_{K0}<0.85$ was $0.932 \pm 0.058 \,(\text{stat}) \pm 0.028 \,(\text{syst})$, demonstrating the successful extraction of precise polarization observables. This result provides essential experimental input for partial wave analysis (PWA) of dynamical coupled-channel (DCC) models, which aim to uncover the underlying mechanisms of $N^{*}$ resonances that emerge in intermediate states of $\pi N$ and $\gamma N$ interactions. Besides, it indicates the feasibility of a strongly polarized $\Lambda$ beam suitable for future $\Lambda p$ scattering experiments (e.g., J-PARC E86). (10.1093/ptep/ptaf168)
  DOI : 10.1093/ptep/ptaf168