Missing-mass measurement of the C reaction at 1.8 GeV/ with the Superconducting Kaon spectrometer

Ichikawa, Yudai   ; Fujita, Manami; Hasegawa, Shoichi   ; Imai, Kenichi*; Nanamura, Takuya; Naruki, Megumi; Sato, Susumu  ; Sako, Hiroyuki   ; Tamura, Hirokazu; Tanida, Kiyoshi   ; Yamamoto, Takeshi  ; 32 of others*

We conducted a measurement of the inclusive missing-mass spectrum in the C reaction at an incident beam momentum of 1.8 GeV/. This measurement was carried out utilizing the Superconducting Kaon Spectrometer (SKS) and the K1.8 beamline spectrometer at the Hadron Experimental Hall in J-PARC. Remarkably, our experimental setup yielded an exceptionaly good energy resolution of 8.2 MeV (FWHM), enabling us to observe significant enhancements in the vicinity of the Be threshold region. In order to estimate the spectrum information, we employed several fitting parameters assumptions. The best agreement with the spectrum shape was obtained with combining quasi-free (QF) component and two-Gaussian functions, with the experimental resolution being held constant. The peak positions were obtained to be (stat.) (syst.) MeV and (stat.) (syst.) MeV. Another model assumption, utilizing quasi-free (QF) and one Breit-Wigner function with (stat.) (syst.) MeV and (stat.) (syst.) MeV, also yielded a similar value.