Lambda hypernuclear spectroscopy up to medium heavy mass number at JLab Hall-C Graduate school of Science, Tohoku Univ. Toshiyuki Gogami

Contents Introduction Experimental setup Analyses Missing mass Summary

Contents Introduction Experimental setup Analyses Missing mass Summary ee u u d u s s u d – p K+K+ Λ γ*γ* (e,e’K + ) reaction

Λ hypernuclear spectroscopy Updated from: O. Hashimoto and H. Tamura, Prog. Part. Nucl. Phys. 57 (2006)  V

Spectroscopic experiment by the (e,e’K + ) reaction p n γ*γ* Λ K+K+ e-e- e + p ➝ e’ + K + + Λ target nucleus ~ 1990’s The (K -,π - ), (π +,K + ) reactions Energy resolution ~ a few MeV n  Λ e’-Spectrometer K + -Spectrometer p e’ p K+ Missing Mass M HY 2000~ The (e,e’K + ) reaction Energy resolution ~0.5 MeV p  Λ

Experimental motivation JLab E (2009, Hall-C) – Elementary processes (Λ,Σ 0 ) – 7 Λ He [1], 9 Λ Li, 10 Λ Be ΛN charge symmetry breaking ΛN-ΣN coupling – 12 Λ B [2][3][4] Consistency check with the past experiments Check analysis progress – 52 Λ V Single particle energy For measurements with heavier targets [1] S.N.Nakamura et al., PRL 110, (2013) [2] T.Miyoshi et al., PRL 90, (2003) [3] L.Yuan, PRC 73, (2006) [4] M.Iodice, PRL 99, (2007)

Contents Introduction Experimental setup Analyses Missing mass Summary HES

Experimental setup JLab Hall-C)

Contents Introduction Experimental setup Analyses Missing mass Summary

Analysis

x, x’, y, y’ p, x’, Reference Target Missing Mass

Energy scale calibration e, K + Polyethylene target (0.45 g/cm 2 ) FWHM ~ 1.8 MeV

Contents Introduction Experimental setup Analyses Missing mass Summary

10 Λ Be, 12 Λ B histograms N sΛ ~190 sΛsΛ pΛpΛ FWHM~0.9 MeV N sΛ ~530 sΛsΛ Preliminary T.Motoba et al., PTP Supplement 185 ( 2010 ) Analyses are in progress to achieve better energy resolution with keeping good linearity. Analyses are in progress to achieve better energy resolution with keeping good linearity.

Summary and outlook JLab E (2009) – Λ, Σ 0, 7 Λ He, 9 Λ Li, 10 Λ Be, 12 Λ B, 52 Λ V – Analyses are in progress Matrix tuning Blind analysis Efficiencies

E collaboration

Backup

New challenging experiment  Λ, Σ 0  Elementary process  Energy scale calibration  12 Λ B  Consistency check  27 Λ Mg, 48 Λ Sc  Deformation  208 Λ Tl  Single particle energy 1m p n γ*γ* Λ K+K+ e-e- target nucleus

New challenging experiment  Λ, Σ 0  Elementary process  Energy scale calibration  12 Λ B  Consistency check  27 Λ Mg, 48 Λ Sc  Deformation  208 Λ Tl  Single particle energy  4 Λ H  Charge symmetry breaking 1m p n Λ π-π- target nucleus

New challenging experiment  Λ, Σ 0  Elementary process  Energy scale calibration  12 Λ B  Consistency check  27 Λ Mg, 48 Λ Sc  Deformation  208 Λ Tl  Single particle energy Design and setup 3-D magnetic field calculation Monte Carlo simulation Experimental operation Analyses Energy scale calibration Tracking 1m  4 Λ H  Charge symmetry breaking

Background events in the HKS z [cm] y [cm] x [cm] KDC1 KDC2 KDC1 KDC2 9 Be, 38.4 [μA] REAL DATA SIMULATION e+e+ 52 Cr target – Luminosity ( 1/10 ) – Worse S/N – Tracking is not easy

Tracking efficiency and residual σ ~ 160 μm Plane efficiency Tracking residual σ ~ 350 μm

52 Cr(e,e’K + ) 52 Λ V Preliminary N bind ~870

Hit wire selection REAL DATA Black : hit wires Blue : selected wires Red : track 52 Cr Target REAL DATA CH 2 Target Compared to the conventional code  Number of K %  Analysis time – 30% CUT

軽い核のミッシングマス 数、分解能 JLab E05-115, Carbon (112mg/cm 2 )

Energy scale calibration e, K + conversion Mx – MΛ < 100 keV/c2

トラッキング困難 REAL DATA Black : hit wires Blue : selected wires Red : track CH 2 Target H 2 O Target

52LV

Singles rate summary Up to ~30 [MHz] Up to ~15 [MHz] HES HKS HKS trigger ~ 10[kHz] HES trigger ~ a few[MHz] HKS-HES Collaboration Meeting, T.Gogami29

B.G. mix rate (real data) a b * hks ntulpe HKS-HES Collaboration Meeting, T.Gogami30

e + simulation SIMULATION To see 1.Number of event 2.Angle & momentum of e + generated in target To see 1.Number of event 2.Angle & momentum of e + generated in target HKS-HES Collaboration Meeting, T.Gogami31

Spectroscopic experiment by the (e,e’K + ) reaction p n γ*γ* Λ K+K+ e-e- e + p ➝ e’ + K + + Λ ee target nucleus Feynman diagram u u d u s s u d – p K+K+ Λ γ*γ* ~ 1990’s The (K -,π - ), (π +,K + ) reactions Energy resolution ~ a few MeV n  Λ e’-Spectrometer K + -Spectrometer p e’ p K+ Missing Mass H HY ~ The (e,e’K + ) reaction Energy resolution ~0.5 MeV p  Λ 2012/9/14JPS meeting in Kyoto, Toshi Gogami

Background events in the HKS z [cm] y [cm] x [cm] KDC1 KDC2 KDC1 KDC2 9 Be, 38.4 [μA] REAL DATA SIMULATION ~2.24 ~4.94 e+e+ 52 Cr target – Luminosity ( 1/10 ) – Worse S/N – Tracking is not easy

10 Λ Be, 12 Λ B histograms N sΛ ~190 sΛsΛ pΛpΛ FWHM~0.9 MeV N sΛ ~530 sΛsΛ Preliminary

Experimental motivation JLab E (2009, Hall-C) – Elementary processes (Λ,Σ 0 ) – 7 Λ He [1], 9 Λ Li, 10 Λ Be ΛN charge symmetry breaking ΛN-ΣN coupling – 12 Λ B Consistency check with the past experiments Check analysis progress – 52 Λ V Single particle energy (systematic な study) ls splitting, core-configuration mixing 将来重く行くため避けられない道 [1] S.N.Nakamura et al., PRL 110, (2013)

Detectors & Trigger K + p, π + e-e- Drift chambers TOF walls (Plastic scintillators) Cherenkov detectors Aerogel (n=1.05) Water (n=1.33) HES HKS HKS trigger (TOF1x2x3) x Chrenkov ~10 kHz HKS trigger (TOF1x2x3) x Chrenkov ~10 kHz HES trigger (TOF1x2) ~2000 kHz HES trigger (TOF1x2) ~2000 kHz Coincidence trigger HES x HKS < 2 kHz Coincidence trigger HES x HKS < 2 kHz 2012/10/6Core2Core in Barcelona, Toshi Gogami36

52 Cr(e,e’K + ) 52 Λ V Mixed event analysis をやる s p d f 数 Preliminary

Electro-production of K + Λ JLab E experiment by the (e,e’K + ) reaction Small Q 2 ( ~0.01 [GeV/c] 2 )  almost real photon Real photon 2013/3/27JPS meeting in Hiroshima, Toshi Gogami38

An importance of measurement of K + Λ production at forward angles At forward angles – Data show lack of consistency – We can access θ K cm ~ 15 deg P.Bydzovsky and T.Mart, Phys. Rev. C 76, (2007) 2013/3/27JPS meeting in Hiroshima, Toshi Gogami39 Real photon Q 2 = 0 [ GeV/c ] 2

Λ, Σ 0 from polyethylene ( CH 2 )target JPS meeting in Hiroshima, Toshi Gogami 2013/3/27 Preliminary 40

Λ, Σ 0 from CH 2 target JPS meeting in Hiroshima, Toshi Gogami 2013/3/27 Preliminary 41 p(e,e’K + )Λ ~1.8MeV (FWHM) Δm = 19 ± 17 keV/c 2 p(e,e’K + )Σ 0 ~1.8MeV (FWHM) Δm = 73 ± 47 keV/c 2 JLab E CH 2, ~ 450 [mg/cm 2 ] ~ 2.0 [μA] ~ 38 [hours]

Cross sections 2013/3/27JPS meeting in Hiroshima, Toshi Gogami42 SAPHIR : K.H. Glander et al., Eur. Phys. J. A 19, (2004) CLAS : R. Bradford et al., Phys. Rev. C 73, (2006) γ (*) + p  K + + Λ γ (*) + p  K + + Σ 0 Preliminary 200 ± 16 ± 91 Preliminary 85 ± 13 ±34

Cross sections 2013/3/27JPS meeting in Hiroshima, Toshi Gogami43 SAPHIR : K.H. Glander et al., Eur. Phys. J. A 19, (2004) CLAS : R. Bradford et al., Phys. Rev. C 73, (2006) JLab E : P. Markoviz et al., Proceedings of SENDAI08 (2009) JLab E : F. Dohrmann et al., arXiv v2 (2007) γ (*) + p  K + + Λ γ (*) + p  K + + Σ 0 Preliminary 200 ± 16 ± 91 Preliminary 85 ± 13 ±34

Q 2 dependence (JLab E05-115) JLab E05-115, CH 2 target Preliminary 2013/3/27JPS meeting in Hiroshima, Toshi Gogami44 W = 1.93 GeV θ CM = 17 degrees W = 1.93 GeV θ CM = 17 degrees 実光子 (SAPHIR)

Apply to u,v-layer Applied to uu’ and vv’ layers, too. Selective region determined by 1X and 2X Convert v v’-layer x x’-layer JPS meeting in Kyoto, Toshi Gogami452012/9/14

Hit wires event display (2) GREEN region Selective region RED markers & lines Selected hit wires BLACK markers & lines Rejected hit wires v v’ u u’u u’ x x’ v v’ u u’u u’ x x’ KDC1 KDC2 particle JPS meeting in Kyoto, Toshi Gogami462012/9/14

Detectors & Trigger K + p, π + e-e- Drift chambers TOF walls (Plastic scintillators) Cherenkov detectors Aerogel (n=1.05) Water (n=1.33) HES HKS 2012/10/6Core2Core in Barcelona, Toshi Gogami47

Detectors & Trigger K + p, π + e-e- Drift chambers TOF walls (Plastic scintillators) Cherenkov detectors Aerogel (n=1.05) Water (n=1.33) HES HKS HKS trigger (TOF1x2x3) x Chrenkov ~10 kHz HKS trigger (TOF1x2x3) x Chrenkov ~10 kHz HES trigger (TOF1x2) ~2000 kHz HES trigger (TOF1x2) ~2000 kHz Coincidence trigger HES x HKS < 2 kHz Coincidence trigger HES x HKS < 2 kHz 2012/10/6Core2Core in Barcelona, Toshi Gogami48

Coincident K + Identification (OFF-LINE) 2012/10/6Core2Core in Barcelona, Toshi Gogami49 Cherenkov selection Coincidence time selection Aerogel (n=1.05) Water (n=1.33) K+K+ π+π+ p CUT p cutπ + cut = HKS T - HES T ( e,e’p ) ( e,e’π + ) CUT ( e,e’K + ) Coincidence of (e,e’K + ) selection CUT m K 2 selection Coincident K + : ~90% ( π + : < 1%, p : < 2% )

10 Λ Be, 12 Λ B histograms N sΛ ~190 sΛsΛ pΛpΛ FWHM~0.9 MeV N sΛ ~530 sΛsΛ Preliminary