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Hyperball -- Hypernuclear spectroscopy at J-PARC -- H. Tamura - PowerPoint PPT Presentation

Jun 13, 2023 •161 likes •352 views

JSP meeting on Sept. 10, 2003 Hyperball -- Hypernuclear spectroscopy at J-PARC -- H. Tamura Tohoku Univ. 1.Physics Subjects 2. Beam and Setup 3. Upgrade of Hyperball 4. Summary 1. Physics subjects of spectroscopy Systematic Study of

  1. JSP meeting on Sept. 10, 2003 Hyperball -- Hypernuclear γ spectroscopy at J-PARC -- H. Tamura Tohoku Univ. 1.Physics Subjects 2. Beam and Setup 3. Upgrade of Hyperball 4. Summary

  2. 1. Physics subjects of γ spectroscopy Systematic Study of High-Precision (2 keV) Hypernuclear Structure = “ Table of Hyper-Isotopes ” � YN interactions spin-spin: 7 Λ Li (KEK E419) Λ N : spin-dependent forces PRL 84 (2000) 5963 Λ N- Σ N / Λ NN forces LS: 9 Λ Be (BNL E930) PRL 84 (2002) 082501 charge symmetry breaking tensor: 16 Λ O (BNL E930) p-wave interaction Ukai, 12aSE Ξ N, ΛΛ interactions New method: Hyperfragments (KEK E509) � Impurity effects B(E2) -> shrinking effect B(E2): 7 Λ Li (KEK E419) PRL 86 (2001) 1982 Shrinkage of n-halo Change of cluster/shell structure � Nuclear medium effect B(M1) -> µ Λ inside a nucleus 11 Λ B (KEK E518) density / isospin dependence

  3. “Day-one experiment” Beam intensity Letter Of Intent [ S = -1 ] Low (<1/10) Med (1/10~1/2) (1) Light Hypernuclei by (K - , π - γ ) p= 1.1 and 0.8 GeV/c High (>1/2) All targets of A<30 Detailed ( γγ 、 γπ/γγ corr., pol, B(E2)) for 12 Λ C, 20 Λ Ne, 28 Λ Si, … => Λ N spin-dep. and Λ N/ Σ N interactions, Impurity effect Λ Pb, ..) by (K - , π - γ ) (2) Medium and heavy Hypernuclei ( 89 Λ Y, 139 Λ La, 208 => p-wave Λ N interaction p=1.8, 1.1, 0.8 E1(p Λ ->s Λ ) (3) Hyperfragments by (K - stop , γγ) / (K - , γπ - ) p= 0.8--0.6 n-rich/ p-rich hypernuclei, A=8 => Impurity effect (Shrinkage of n-halo) (4) Mirror / n-rich Hypernuclei by (K - , π 0 γ ) p= 1.1 and 0.8 4 Λ H( 4 Λ He) , 12 Λ B( 12 Λ C), 16 Λ N( 16 Λ O) => Charge Sym. Break. ( π + , K + γ ) or (K - , π - γ ) p=1.1 (5) B(M1) by DSAM => µ Λ in nucleus 11 7 Λ B, Λ Li etc. (K - , π - γ weak) p= 1.1 or 0.8 (6) B(M1) by γ -weak 12 Λ C, heavier

  4. Beam intensity Low (<1/10) Letter Of Intent [ S = -2 ] Med (1/10~1/2) High (>1/2) (7) Ξ atom by (K - , K + γ ) p= 1.8 GeV/c ・ => Ξ N interaction wide range of A (8) ΛΛ− nuclei by (K - , K + π - γ ) p=1.8 ・ => ΛΛ interaction several p-shell targets

  5. “Day-one experiment” Beam intensity Letter Of Intent [ S = -1 ] Low (<1/10) Med (1/10~1/2) (1) Light Hypernuclei by (K - , π - γ ) High (>1/2) p= 1.1 and 0.8 GeV/c All targets of A<30 Detailed ( γγ 、 γπ/γγ corr., pol, B(E2)) for 12 Λ C, 20 Λ Ne, 28 Λ Si, … => Λ N spin-dep. and Λ N/ Σ N interactions, Impurity effect Λ Pb, ..) by (K - , π - γ ) (2) Medium and heavy Hypernuclei ( 89 Λ Y, 139 Λ La, 208 p=1.8, 1.1, 0.8 => p-wave Λ N interaction E1(p Λ ->s Λ ) (3) Hyperfragments by (K - stop , γγ) / (K - , γπ - ) p= 0.8--0.6 n-rich/ p-rich hypernuclei, A=8 => Impurity effect (Shrinkage of n-halo) (4) Mirror / n-rich Hypernuclei by (K - , π 0 γ ) p= 1.1 and 0.8 4 Λ H( 4 Λ He) , 12 Λ B( 12 Λ C), 16 Λ N( 16 Λ O) => Charge Sym. Break. ( π + , K + γ ) or (K - , π - γ ) p=1.1 (5) B(M1) by DSAM => µ Λ in nucleus 11 Λ B, 7 Λ Li etc. (K - , π - γ weak) p= 1.1 or 0.8 (6) B(M1) by γ -weak 12 Λ C, heavier

  6. 12 C ( π + ,K + ) 12 Λ C (1) Light hypernuclei SKS ∆ E~1.5 MeV(FWHM) --- example of 12 Λ C Simulation: K1.1, 10g/cm 2 , 120 hours a l Expected transitions c b g d k h o p f k e j n h i g j e c b l m f i d a

  7. c γγ coincidence - ->1 1 - ) coinc. with a (2 1 k h and angular correlations j f 12 Λ C: simulation γγ coincidence spectrum - -> 2 1 - ) coinc. with c (1 2 h -> level scheme k θ πγ angular correlation -> spin assignment

  8. (1) Light hypernuclei Impurity effect --- example of 20 Λ Ne : change of cluster structure shrinking effect considered (cluster model)

  9. “Day-one experiment” Beam intensity Letter Of Intent [ S = -1 ] Low (<1/10) Med (1/10~1/2) (1) Light Hypernuclei by (K - , π - γ ) p= 1.1 and 0.8 GeV/c High (>1/2) All targets of A<30 Detailed ( γγ 、 γπ/γγ corr., pol, B(E2)) for 12 Λ C, 20 Λ Ne, 28 Λ Si, … => Λ N spin-dep. and Λ N/ Σ N interactions, Impurity effect Λ Pb, ..) by (K - , π - γ ) (2) Medium and heavy Hypernuclei ( 89 Λ Y, 139 Λ La, 208 => p-wave Λ N interaction p=1.8, 1.1, 0.8 E1(p Λ ->s Λ ) (3) Hyperfragments by (K - stop , γγ) / (K - , γπ - ) p= 0.8--0.6 n-rich/ p-rich hypernuclei, A=8 => Impurity effect (Shrinkage of n-halo) (4) Mirror / n-rich Hypernuclei by (K - , π 0 γ ) p= 1.1 and 0.8 4 Λ H( 4 Λ He) , 12 Λ B( 12 Λ C), 16 Λ N( 16 Λ O) => Charge Sym. Break. ( π + , K + γ ) or (K - , π - γ ) p=1.1 (5) B(M1) by DSAM => µ Λ in nucleus 11 7 Λ B, Λ Li etc. (K - , π - γ weak) p= 1.1 or 0.8 (6) B(M1) by γ -weak 12 Λ C, heavier

  10. “Day-one experiment” Beam intensity Letter Of Intent [ S = -1 ] Low (<1/10) Med (1/10~1/2) (1) Light Hypernuclei by (K - , π - γ ) p= 1.1 and 0.8 GeV/c High (>1/2) All targets of A<30 Detailed ( γγ 、 γπ/γγ corr., pol, B(E2)) for 12 Λ C, 20 Λ Ne, 28 Λ Si, … => Λ N spin-dep. and Λ N/ Σ N interactions, Impurity effect Λ Pb, ..) by (K - , π - γ ) (2) Medium and heavy Hypernuclei ( 89 Λ Y, 139 Λ La, 208 => p-wave Λ N interaction p=1.8, 1.1, 0.8 E1(p Λ ->s Λ ) (3) Hyperfragments by (K - stop , γγ) / (K - , γπ - ) p= 0.8--0.6 n-rich/ p-rich hypernuclei, A=8 => Impurity effect (Shrinkage of n-halo) (4) Mirror / n-rich Hypernuclei by (K - , π 0 γ ) p= 1.1 and 0.8 4 Λ H( 4 Λ He) , 12 Λ B( 12 Λ C), 16 Λ N( 16 Λ O) => Charge Sym. Break. ( π + , K + γ ) or (K - , π - γ ) p=1.1 (5) B(M1) by DSAM => µ Λ in nucleus 11 7 Λ B, Λ Li etc. (K - , π - γ weak) p= 1.1 or 0.8 (6) B(M1) by γ -weak 12 Λ C, heavier

  11. (5),(6) B(M1) measurements µ Λ in nucleus -> medium effect of baryons g Λ ψ Λ ↑ ψ c J c +1/2 J c "hypernuclear M1 fine structure" J c -1/2 ψ Λ ↓ ψ core nucleus c Λ in s-orbit hypernucleus µ z | B(M1) ∝| < Φ f | Φ i > | 2 = | < ψ Λ ↑ ψ c | g c J c z + g Λ J Λ z | ψ Λ ↓ ψ c > | 2 ∝ ( g c - g Λ ) 2 Accuracy ∆ g Λ < 5% achievable � Doppler shift attenuation method [ same as B(E2), established] Weak K - or π + beam usable for light hypernuclei; � γ -weak coincidence method [ new, only possible at J-PARC] Λ C and heavy hypernuclei; Intense K - beam necessary for 12

  12. B(M1) measurement by γ -weak coincidence method 400 hours for 12 Λ C -> 5% error of B(M1)

  13. K - Beam momentum for S=-1 0.8, 1.8 GeV/c (K - , π - ) = large σ and non-spin-flip + 1.1 GeV/c (K - , π - ) = spin-flip ・ Reveal all the levels ・ Level assignment ・ Spin-flip B(M1) -> µ Λ

  14. 3. Beam and Setup Beamline: K1.1 � K - at 1.1, 0.8 GeV/c 4.2x10 7 K - /spill K/ π > 1 π + at 1.05 GeV/c Spectrometer: SPESII � (existing) Hyperball3 ∆ p/p < 2 MeV (FWHM) Ω ~ 20 msr SKS (100 msr) is better Hyperball3 (2007?) � ε > 10% at 1 MeV or Hyperball2 (2003) ε ~ 5% at 1 MeV

  15. Comparison of K1.1, K1.1BR, and K1.8 Subjects (1), (2), (4), (5), (6) require production of spin-flip states by 1.1 GeV/c (K - , π - ) reaction. Beamline K1.1 K1.1BR K1.8 Momentum 1.1 1.1 1.1 K - intensity /spill 4.2x10 7 1.0x10 7 0.049x10 7 K/ π > 1 / 1 ~ 1 / 5 > 1 / 1 Λ Li (3/2 + ) (spin-flip state): d σ/ d Ω = 17 µ b/sr @10 0 , Hyperball3 eg. 7 Ω ( msr) 20 (SPESII) 50 (SKS) γ yield (counts/hour) Ge rate limit = 2x10 7 /spill 280 44 17 0.2 (E419) (Ge no rate limit) (580) (134) (17) Ge damage (relative) 1 6 1

  16. 4. Upgrade of Hyperball Hyperball2 : under construction (2003) collaboration with CYRIC, Tohoku � Clover Ge (r.e. >120%) +BGO x 6 added � Peak eff. ~ 2.5% -> 5% at 1 MeV � Beam test of Clover Ge (T536, June 2003) OK � VME-based fast readout � Improvement of preamplifier

  17. Hyperball3 (Segmented Clover version) 14 sets � ε > 10% at 1 MeV (x4 of Hyperball) r.e.= 350% � Rate limit PWO ~2x10 7 particles /s (x5) counters � Yield: x20 for single γ x80 for γγ PWO counters

  18. R&D for Hyperball3 � Waveform readout method –> pileup decomposition, baseline restoration High resolution waveform digitizer Data transfer Analysis software � Lower-gain, faster-reset preamplifiers � Faster suppressor than BGO (PWO, BSO, ..) � LN2-free cooling � Radiation damage

  19. 5. Summary γ spectroscopy is one of the main strangeness � programs in J-PARC. Systematic studies for various subjects � (YN interaction, impurity effects, medium effects) are proposed. Regarded as a day-one experiment. K1.1 + Hyperball3 gives 10 3 improvement. � R&Ds for Hyperball3 have been started. �

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