H. Sugimura

Hypernuclear spectroscopy of products from Li-6 projectiles on a carbon target at 2 A GeV

Abstract A novel experiment, aiming at demonstrating the feasibility of hypernuclear spectroscopy with heavy ion beams, was conducted. Using the invariant mass method, the spectroscopy of hypernuclear products of 6Li projectiles on a carbon target at 2 A GeV was performed. Signals of the Λ-hyperon and H Λ 3 and H Λ 4 hypernuclei were observed for final states of p + π − , He 3 + π − and He 4 + π − , respectively, with significance values of 6.7, 4.7 and 4.9σ. By analyzing the proper decay time from secondary vertex distribution with the unbinned maximum likelihood fitting method, their lifetime values were deduced to be 262 − 43 + 56 ± 45 ps for Λ, 183 − 32 + 42 ± 37 ps for H Λ 3 , and 140 − 33 + 48 ± 35 ps for H Λ 4 .

Observation of Spin-Dependent Charge Symmetry Breaking in

The energy spacing between the spin-doublet bound state of _{Λ}^{4}He(1^{+},0^{+}) was determined to be 1406±2±2  keV, by measuring γ rays for the 1^{+}→0^{+} transition with a high efficiency germanium detector array in coincidence with the ^{4}He(K^{-},π^{-})_{Λ}^{4}He reaction at J-PARC. In comparison to the corresponding energy spacing in the mirror hypernucleus _{Λ}^{4}H, the present result clearly indicates the existence of charge symmetry breaking (CSB) in ΛN interaction. By combining the energy spacings with the known ground-state binding energies, it is also found that the CSB effect is large in the 0^{+} ground state but is vanishingly small in the 1^{+} excited state, demonstrating that the ΛN CSB interaction has spin dependence.

\Lambda N

We have observed a “

Interaction: Gamma-Ray Spectroscopy of

K^{-}pp

^4_{\Lambda }

”-like structure in the

He

d(\pi ^{+ },K^{+ })

Observation of the “K− pp”-like structure in the d(π+, K+) reaction at 1.69 GeV/c

reaction at 1.69 GeV

Search for the Θ+ pentaquark via the π(-)p→K(-)X reaction at 1.92 GeV/c.

/c

Inclusive spectrum of the d(π+, K+) reaction at 1.69 GeV/c

. In this reaction, a

Search for HΛ6 hypernucleus by the Li6(π−,K+) reaction at pπ−=1.2GeV/c

\Lambda (1405)