Workshop: Proton Polarimeter for the Study of Light Kaonic Nuclei
at our new location at PSK . Participants were Masa IWASAKI, Fuminori SAKUMA, Takumi YAMAGA, Tadashi HASHIMOTO, Takuya NANAMURA, Jerzy SMYRSKI, Florin SIRGHI, Johann MARTON and Johann ZMESKAL. Thanks for coming and the interesting discussions!
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The study of the antikaon-nucleon interaction is one of the most important subjects to understand meson-baryon interactions in low energy quantum chromodynamics (QCD). Extensive measurements of anti-kaonic hydrogen atoms [1–3] and low-energy anti-kaon hydrogen scattering [4] have revealed the strongly attractive nature of the anti-kaon nucleon interaction. The possible existence of deeply-bound anti-kaonic nuclei states has been widely discussed [5–13]. Anti-kaonic nuclei are predicted to be compact due to the strong anti-kaon nucleon attraction, suggesting that a new form of high-density nuclear matter is realized in anti-kaonic nuclei systems.
Among the kaonic nuclei, the anti-kaon nucleon system (K−pp) is of special interest, because it is the lightest S = −1 anti-kaon nucleus whose existence is supported by many theoretical works today. Despite considerable experimental efforts over the past 20 years, the clear prove of the existence of K−pp was a challenging task. Finally, the “E15” experiment [14] at J-PARC confirmed the existence of a K−pp bound state by using the in-flight K− + 3He ® K−pp + n reaction. A distinct peak structure was observed well below the K- + p + p mass threshold in the Λp invariant-mass (IM) spectrum, interpreting that K−pp is a bound system which decays into Lp.
Due to the excellent result of “E15”, an improved apparatus is now under construction and a proposal for an extended experimental programme “E80” is put forward to the J-PARC Programme Advisory Committee. Detailed and systematic studies are planned from the simplest system K−p [º L(1405)] to be expanded to multi-nucleon systems like K−NNNN and double kaon systems like K−K−NN.
In addition, the spin and parity of the K-NN state should be determined, an important information to reveal the structure of anti-kaon bound systems, using a dedicated polarimeter detector setup.
References
[1] M. Iwasaki et al. Phys. Rev. Lett. 78 (1997) 3067.
[2] G. Beer et al. Phys. Rev. Lett. 94 (2005) 212302.
[3] M. Bazzi et al. Phys. Lett. B704 (2011) 113.
[4] A. D. Martin Nucl. Phys. B179 (1981) 33.
[5] Y. Nogami Phys. Lett. 7 (1963) 288.
[6] T. Yamazaki and Y. Akaishi Phys. Lett. B535 (2002) 70.
[7] N. V. Shevchenko, A. Gal, and J. Mares Phys. Rev. Lett. 98 (2007) 082301.
[8] Y. Ikeda and T. Sato Phys. Rev. C76 (2007) 035203.
[9] S. Wycech and A. M. Green Phys. Rev. C79 (2009) 014001.
[10] A. Dote, T. Hyodo, and W. Weise Phys. Rev. C79 (2009) 014003.
[11] T. Sekihara, E. Oset, and A. Ramos Prog. Theor. Exp. Phys. 2016 (2016) 123D03.
[12] S. Ohnishi, W. Horiuchi, T. Hoshino, K. Miyahara, and T. Hyodo Phys. Rev. C95 (2017) 065202.
[13] A. Dote, T. Inoue, and T. Myo Phys. Lett. B784 (2018) 405.
[14] E15 collaboration, M. Iwasaki et al. Phys. Lett. B789 (2019) 620–625.
Timetable:
10:00 Welcome
(10 min.) J. Zmeskal
10:10 Results and prospects of kaonic nuclei at J-PARC
(20 min.) F. Sakuma
10:30 Proton polarimeter for determination of spin & parity
of KbarNN
(30 min.) T. Yamaga
11:00 Straw tube detectors for PANDA
(30 min.) J. Smyrski
11:30 Coffee break
11:45 Discussion - Towards a Polarimeter for E80
(90 min.)
13:15 Lunch
14:00 Experimental study of the state KbarNNN and beyond
at J-PARC
(45 min.) T. Hashimoto
14:45 Development of large acceptance spectrometer for systematic study of kaonic nuclei at J-PARC
(45 min.) T. Nanamura
15:30 Coffee break
(15 min.)
15:45 Final Discussion
(45 min.)