Precision spectroscopy of deeply bound pionic states in tin isotopes - PowerPoint PPT Presentation

Precision spectroscopy of deeply bound pionic states in tin isotopes at RIBF Takahiro Nishi � Advanced Meson Science Laboratory, RIKEN DeukSoon Ahn, Georg P.A. Berg, Masanori Dozono, Daijiro Etoh, Hiroyuki Fujioka, Naoki Fukuda, � RILAC Nobuhisa Fukunishi, Hans Geissel, Emma Haettner, Tadashi Hashimoto, Ryugo S. Hayano, Satoru Hirenzaki, Hiroshi Horii, Natsumi Ikeno, Naoto Inabe, Kenta Itahashi* , Sathoshi Itoh, Masahiko Iwasaki, Daisuke Kameda, Shouichiro Kawase, Keichi Kisamori, Yu Kiyokawa, Toshiyuki Kubo, Kensuke AVF Kusaka, Hiroaki Matsubara, Masafumi Matsushita, Shin'ichiro Michimasa, Kenjiro Miki, Go Mishima, RIPS Hiroyuki Miya, Daichi Murai, Yohei Murakami, Hideko Nagahiro, Masaki Nakamura, Megumi Niikura, SRC Takahiro Nishi**, Shumpei Noji, Kota Okochi, Shinsuke Ota, Naruhiko Sakamoto, Kimiko Sekiguchi, Hiroshi Suzuki, Ken Suzuki, Motonobu Takaki, Hiroyuki Takeda, Yoshiki K. Tanaka, Koichi Todoroki, Kyo RRC fRC Tsukada, Tomohiro Uesaka, Yasumori Wada, Yuni N. Watanabe, Helmut Weick, Hiroyuki Yamada, BigRIPS Hiroki Yamakami, Yoshiyuki Yanagisawa and Koichi Yoshida � IRC *spokesperson, ** co-spokesperson 0 50 m University of Tokyo, RIKEN, Nishina Center, University of Notre Dame, Tohoku University, Kyoto University, 
 GSI Helmholtzzentrum für Schwerionenforschung GmbH, Nara Women's University, Osaka University, � Stefan Meyer Institute

MIN2016, Kyoto, August 1st 2016 2 Deeply bound pionic states Half density radius Nucleus pion density pion orbit : 
 surface on the nuclei 1s 2s π − Nuclear density deeply bound pionic states � → Large overlap between π and A good probe for strong interaction at finite ρ ~ probing 0.6 ρ 0 overlap 1s 2s radius [fm] N. Ikeno et al. , PTP126(2011)483.

MIN2016, Kyoto, August 1st 2016 3 Strong interaction and pionic states 121 Sn- π - BE, Γ of 1 s pionic state � ⇔ strong interaction effect π -A s-wave optical potential (s-wave) V s ( r ) = − 2 � µ [ � 1 { b 0 � + b 1 �� } + � 2 B 0 � 2 ] ρ = ρ p + ρ n � δρ = ρ p − ρ n N. Ikeno et al., Prog. Theor. Phys. 126 (2011) 483. � S. Itoh, Doctoral Dissertation, Univ. of Tokyo (2011)

MIN2016, Kyoto, August 1st 2016 4 Strong interaction and pionic states 121 Sn- π - BE, Γ of 1 s pionic state � ⇔ strong interaction effect π -A s-wave optical potential (s-wave) V s ( r ) = − 2 � µ [ � 1 { b 0 � + b 1 �� } + � 2 B 0 � 2 ] strong relation with quark condensate Order parameter of � chiral symmetry breaking N. Ikeno et al., Prog. Theor. Phys. 126 (2011) 483. � S. Itoh, Doctoral Dissertation, Univ. of Tokyo (2011)

MIN2016, Kyoto, August 1st 2016 5 Production method; (d, 3 He) reaction A Pb( d , 3 He) recoilless condition is satisfied � d 3 He 350 @T d = 250 MeV/u p p Momentum transfer [MeV/c] n 300 p n n 250 BE π ~ 0 MeV � neutron ! n 200 BE π ~ 5 MeV hole π - 150 A-1 Pb × π - 100 A Pb 50 0 100 150 200 250 300 350 400 Incident energy [MeV/u] Pion bound state � threshold (coupled with n hole) - i s a u q e e r f 3 He kinetic energy

pionic atoms measured in GSI MIN2016, Kyoto, August 1st 2016 6 Deeply bound pionic atoms at GSI Calibration Nuclear chart 1s 123 Sn 119 Sn 115 Sn NuDat K. Suzuki et al., PRL92 072302 (2004) Systematic study of pionic Sn isotopes ~ 3 month measurement for 3 isotopes

MIN2016, Kyoto, August 1st 2016 7 Extract b 1 from experimental data Contour plot of χ 2 π -A s-wave optical potential free 0.7 0.8 0.9 1.0 b 1 / b 1 V s ( r ) = − 2 � µ [ � 1 { b 0 � + b 1 �� } + � 2 B 0 � 2 ] 205 Pb 123,119,115 Sn, 28 Si, 20 Ne, 16 O free value 4 σ 0.050 3 σ Im B 0 [m π -4 ] 2 σ 1 σ 0.048 0.046 0.044 -0.13 -0.12 -0.11 -0.10 -0.09 b 1 [m π -1 ] � ¯ qq � ρ b free 1 qq � � 0 . 66 ± 0 . 06 = 0 . 78 ± 0 . 05 � ¯ b 1 cf. theoretical prediction ~ 0.65 ※ b 0 , ReB 0 are deduced from data of light / symmetric pionic atoms

MIN2016, Kyoto, August 1st 2016 8 Extract b 1 from experimental data Contour plot of χ 2 π -A s-wave optical potential free 0.7 0.8 0.9 1.0 b 1 / b 1 V s ( r ) = − 2 � µ [ � 1 { b 0 � + b 1 �� } + � 2 B 0 � 2 ] 205 Pb 123,119,115 Sn, 28 Si, 20 Ne, 16 O free value 4 σ error of b 1 in medium is still large � 0.050 3 σ compared with that in vacuum!! � Im B 0 [m π -4 ] 2 σ 1 σ two main sources are � 0.048 � 0.046 ・ experimental error � ・ neutron distribution ambiguities 0.044 -0.13 -0.12 -0.11 -0.10 -0.09 b 1 [m π -1 ] � ¯ qq � ρ b free 1 qq � � 0 . 66 ± 0 . 06 = 0 . 78 ± 0 . 05 � ¯ b 1 cf. theoretical prediction ~ 0.65 ※ b 0 , ReB 0 are deduced from data of light / symmetric pionic atoms

MIN2016, Kyoto, August 1st 2016 9 Extract b 1 from experimental data Contour plot of χ 2 π -A s-wave optical potential free 0.7 0.8 0.9 1.0 b 1 / b 1 V s ( r ) = − 2 � µ [ � 1 { b 0 � + b 1 �� } + � 2 B 0 � 2 ] 205 Pb 123,119,115 Sn, 28 Si, 20 Ne, 16 O free value 4 σ error of b 1 in medium is still large � 0.050 3 σ compared with that in vacuum!! � Im B 0 [m π -4 ] 2 σ 1 σ two main sources are � 0.048 � 0.046 ・ experimental error � ・ neutron distribution ambiguities 0.044 -0.13 -0.12 -0.11 -0.10 -0.09 b 1 [m π -1 ] To extract b 1 with higher precision � � ¯ qq � ρ b free 1 qq � � 0 . 66 ± 0 . 06 = 0 . 78 ± 0 . 05 � ¯ b 1 improve resolution / calibration � cf. theoretical prediction ~ 0.65 More isotopes

by dispersion matching optics 200 ~ 300 keV MIN2016, Kyoto, August 1st 2016 10 Experiment at RIBF, RIKEN RILAC AVF RIPS SRC RRC fRC BigRIPS IRC 0 50 m GSI RIBF Improvement intensity × 60 ~ 10 11 / 6 s (1 spill) ~ 10 11 / 6 s (1 spill) ~ 10 12 / s ~ 10 12 / s angular acceptance 
 15 / 10 mrad 40 / 60 mrad × 16 (H / V) resolution (FWHM) 400 keV improve

MIN2016, Kyoto, August 1st 2016 11 First production experiment in 2014 � @ RIKEN (11 days) aim of the experiment � ・ improve the resolution ~ 300 keV 
 ・ first step of the systematic study with enough statistics

MIN2016, Kyoto, August 1st 2016 12 First production experiment in 2014 � @ RIKEN (11 days) NuDat Nuclear chart Measured targets in exp. at GSI � Measured targets in exp. 2014 at RIKEN 122 Sn: relatively large cross section � 117 Sn: first odd-A target

MIN2016, Kyoto, August 1st 2016 13 Experimental setup 3 He ~ 10 2 Hz � p ~ 10 5 Hz � RIKEN Fragment Separator 
 Detector Installation (signal) (break up/ background) BigRIPS F7 F0 F5 Target (strip) Beam Transfer line SRC S uperconducting � R ing � d beam 250 MeV/u � C yclotron ~ 10 12 /s

MIN2016, Kyoto, August 1st 2016 14 Experimental setup: detectors 3 He ~ 10 2 Hz � p ~ 10 5 Hz � Tracking by MWDC Detector Installation (signal) (break up/ background) F7 F0 F5 Target (strip) Measured position, angle@F5 � + � transfer matrix SRC P 3He + reaction angle at target Multi Wire Drift Chamber

MIN2016, Kyoto, August 1st 2016 15 Production run: 122 Sn target position spectrum of 3 He 35000 30000 25000 counts / mm 20000 15000 # of 3 He: ~ 4 × 10 6 � 10000 ~ 1 day measurement 5000 0 -100 -50 0 50 100 3 position of He at F5 focal plane [mm] High P 3He

MIN2016, Kyoto, August 1st 2016 16 Production run: 122 Sn target position spectrum of 3 He Eex spectrum of 121 Sn θ reac < 1.0° bound state � 35000 of π in 121 Sn 30000 y 25000 r counts / mm a n i 20000 m i l e 15000 r P # of 3 He: ~ 4 × 10 6 � 10000 ~ 1 day measurement 5000 0 -100 -50 0 50 100 3 position of He at F5 focal plane [mm] High P 3He High P 3He quasi-free π - production threshold The spectrum seems to achieve the best resolution 
 among the past deeply-bound pionic atom experiment.

production threshold 139.57 MeV quasi-free π - MIN2016, Kyoto, August 1st 2016 17 Fitting of the E ex spectrum : 122 Sn target θ reac < 1.0° blue solid line : fit function 121 Sn y - - - 1s - - - 2s - - - 3s r a n - - - 2p - - - 3p i m i l e r P fit region The E ex spectrum is fit by the function with several components � → deduce binding energies and widths of pionic states ※ calibration of E ex is still on going…

MIN2016, Kyoto, August 1st 2016 18 Fitting of the E ex spectrum : 122 Sn target θ reac < 1.0° 121 Sn background (solid line / flat) � - - - 1s � + 1 s pionic state (dashed line) each pionic state � → several configuration � with different neutron holes 
 3 s 1/2 , 2 d 3/2 , 1 h 11/2 1 g 7 /2 , 2 d 5 /2 (i), (ii) each configuration � → Voigtian / σ exp is fixed relative strength � neutron hole Eex [MeV] for pionic 1 s state 2 d 3/2 0.000 0.09 1 h 11 /2 0.006 0.001 3 s 1 /2 0.060 1 1 g 7 /2 0.926 0.003 2 d 5 /2 (i) 1.121 0.12 2 d 5 /2 (ii) 1.403 0.06

MIN2016, Kyoto, August 1st 2016 19 Fitting of the E ex spectrum : 122 Sn target θ reac < 1.0° 121 Sn background (solid line / flat) � - - - 1s � - - - 2p + 1 s pionic state (dashed line) � + 2 p pionic state (dashed line)

MIN2016, Kyoto, August 1st 2016 20 Fitting of the E ex spectrum : 122 Sn target θ reac < 1.0° 121 Sn background (solid line / flat) � - - - 1s - - - 2s � - - - 2p + 1 s pionic state (dashed line) � + 2 p pionic state (dashed line) � + 2 s pionic state (dashed line)