Speaker
Dr
Shinji Okada
(RIKEN)
Description
High-resolution x-ray spectroscopies of hadronic atoms will be performed with an x-ray spectrometer based on an array of superconducting transition-edge-sensor (TES) microcalorimeters which have achieved remarkable development in recent years [1]. The instrument offers unprecedented full-width-at-half-maximum energy resolutions of 2 - 3 eV at 6 keV being two order of magnitude improved resolution compared with the conventional semiconductor detector, and has a large collecting area of about 20 mm^2 thanks to recent technological advances in multiplexed readout of a TES multi-pixel array. This will open new door to investigate hadron-nucleus strong interactions and provide accurate charged-hadron mass values.
A hadronic atom is a Coulomb-bound system formed by a negatively charged hadron (e.g., pi^-, K^-, pbar, Sigma^-, Xi^-), electrons, and a nucleus. Effects of the strong interaction between the hadron and atomic nucleus are experimentally extracted from characteristic x-ray-emission spectroscopy of the most tightly bound energy levels that are the most perturbed by the strong force (e.g., [2-4] as the recent measurements).
As for kaonic atoms, many experiments have collected data on a variety of targets [5]; however, the energy resolution of the conventional semiconductor spectrometers employed in these experiments is insufficient to see the small spectral effects due to the strong interaction. As a result, the depth of the K^- - nucleus potential at zero energy remains unknown. This is closely related to the investigation of bound states of the kaon in the nucleus being one of the hottest topics in strangeness nuclear physics now. Aiming at a breakthrough in this field, we are planning to perform ultra-high-resolution x-ray spectroscopy of kaonic atoms at J-PARC hadron beamline using arrays of TES microcalorimeters developed by NIST, which is the first application of TES to a hadronic atom experiment. Additionally, hadronic-atom x-ray spectroscopy has been used as a tool for measuring the charged hadron mass; we intend to improve the precision of the charged kaon mass measurement with TES spectrometers.
In this talk we will give an overview of this project and the recent progress.
[1] C. Enss (ed.), Cryogenic Particle Detection, Topics in Applied Physics, vol. 99, Springer, 2005.
[2] S. Okada et al., Phys. Lett. B 653 (2007) 387-391.
[3] SIDDHARTA collaboration, Phys. Lett. B 697 (2011) 199-202.
[4] SIDDHARTA collaboration, Phys. Lett. B 704 (2011) 113-117.
[5] C.J. Batty, E. Friedman, A. Gal, Phys. Rep. 287 (1997) 385-445.
Primary author
Dr
Shinji Okada
(RIKEN)
Co-authors
Dr
C. Curceanu
(INFN-LNF)
Dr
D. A. Bennett
(NIST)
Dr
D. R. Schmidt
(NIST)
Dr
D. S. Swetz
(NIST)
Prof.
E. Widmann
(Stefan Meyer Institute)
Dr
G. C. O'Neil
(NIST)
Dr
H. Outa
(RIKEN)
Dr
H. Tatsuno
(The University of Tokyo)
Dr
J. Marton
(Stefan Meyer Institute)
Dr
J. N. Ullom
(NIST)
Dr
J. W. Fowler
(NIST)
Dr
J. Zmeskal
(Stefan Meyer Institute)
Dr
K. Itahashi
(RIKEN)
Dr
M. Iliescu
(INFN-LNF)
Prof.
M. Iwasaki
(RIKEN)
Dr
M. Sato
(RIKEN)
Prof.
R. S. Hayano
(The University of Tokyo)
Dr
S. Ishimoto
(KEK)
Dr
S. Yamada
(Tokyo Metropolitan University)
Dr
T. Hashimoto
(RIKEN)
Dr
W. B. Doriese
(NIST)
