Kaon photoproduction on the deuteron at Sendai

Abstract

Abstract. The photoproduction of K 0 and Λ on the deuteron was measured in order to investigate the γn → K 0 Λ reaction process near the threshold (E γ = 0.8-1.1 GeV). K 0 and Λ events were clearly seen in the π + π − and the pπ − invariant mass spectra, respectively. The momentum spectra of the γd → K 0 X and the γd → ΛX reactions were derived. Additionally, the energy dependence of the integral cross section for the Λ production was also obtained. The K 0 momentum spectra were in agreement with the previous results within statistical errors. The angular distribution of the γn → K 0 Λ reaction in the center of mass system was extracted and it had the backward distribution. The total cross section of the γn → K 0 Λ reaction, which was estimated by subtracting the contribution of K + Λ process from the Λ production on the deuteron, was almost the same as that of the γp → K + Λ.

Photoproduction of K+Λ and K0Λ on Deuteron

“…Currently available γn → K 0 Λ cross sections were measured with Neutral Kaon Spectrometer (NKS) [4,5] and Neutral Kaon Spectrometer 2 (NKS2) [6][7][8]. They are magnetic spectrometers with geometrical acceptances of ∼ π sr developed for a simultaneous detection of charged particles.…”

“…They are magnetic spectrometers with geometrical acceptances of ∼ π sr developed for a simultaneous detection of charged particles. From the invariant mass of π + and π − , K 0 S was identified and γd → K 0 X differential cross sections were reported [4][5][6]. From the pπ − invariant mass, Λ was identified and inclusive γd → ΛX cross sections were reported [6][7][8].…”

“…From the invariant mass of π + and π − , K 0 S was identified and γd → K 0 X differential cross sections were reported [4][5][6]. From the pπ − invariant mass, Λ was identified and inclusive γd → ΛX cross sections were reported [6][7][8]. In the latter study, total cross sections of γn → K 0 Λ were obtained from inclusive measurements of γd → ΛX with a help of theoretical calculations.…”

“…In Fig. 1, γd → K 0 Λp cross sections reported by NKS2 [6], γp → K + Λ cross sections reported by CLAS [9] and SAPHIR [10], theoretical calculations for γd → K 0 Λp cross sections by KM and SLA, and γn → K 0 Λ cross sections by RPR are summarized. In the calculation of γn → K 0 Λ with the SLA model, there is a free parameter r K 1 Kγ which cannot be fixed by the fitting to the proton target data.…”

“…Our preliminary results for γd → K 0 Λp cross sections [6] derived with a help of KM (triangles) and SLA (squares) calculations are plotted. Curves for K 0 photoproduction cross sections are calculated with KM (solid curve), SLA with r K 1 Kγ = −1.5 (dashed curve), and RPR (dotted curve) [11].…”