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 (e,e’K+) reaction e p e u u d γ* u K+ –s s u Λ d Λ hypernuclear spectroscopy 52 LV Updated from: O. Hashimoto and H. Tamura, Prog. Part. Nucl. Phys. 57 (2006) 564. Spectroscopic experiment by the (e,e’K+) reaction pe’ e + p ➝ e’ + K+ + Λ e’-Spectrometer eγ* p n Λ target nucleus Missing Mass MHY K+ K+-Spectrometer pK+ ~ 1990’s The (K-,π-) , (π+,K+) reactions • Energy resolution ~ a few MeV • n Λ 2000~ The (e,e’K+) reaction • Energy resolution ~0.5 MeV • pΛ Experimental motivation • JLab E05-115 (2009, Hall-C) – Elementary processes (Λ,Σ0) – 7ΛHe[1], 9ΛLi, 10ΛBe • ΛN charge symmetry breaking • ΛN-ΣN coupling – 12 B[2][3][4] Λ • Consistency check with the past experiments • Check analysis progress – 52 V Λ • Single particle energy • For measurements with heavier targets [1] S.N.Nakamura et al., PRL 110, 012502 (2013) [2] T.Miyoshi et al., PRL 90, 232502 (2003) [3] L.Yuan, PRC 73, 044607 (2006) [4] M.Iodice, PRL 99, 052501 (2007) Contents • Experimental setup HES Experimental setup (E05-115 @ JLab Hall-C) 10 msr ∆𝑝 −4 = 2 × 10 𝑝 10 msr ∆𝑝 −4 = 2 × 10 𝑝 Contents • Analyses Analysis Analysis x, x’, y, y’ x, x’, y, y’ @ Reference plane @ Reference plane p, x’, y’ p, x’, y’ @ Target Missing Mass Energy scale calibration e, K+ Polyethylene target (0.45 g/cm2) FWHM ~ 1.8 MeV Contents • Missing mass 10 ΛBe, 12 ΛB histograms FWHM~0.9 MeV FWHM~0.9 MeV Analyses are in progress s s p NsΛto ~190 achieve better energy resolution NsΛ~530 with keeping good linearity. Λ Λ Λ T.Motoba et al., PTP Supplement 185 ( 2010 ) Summary and outlook • JLab E05-115 (2009) – Λ, Σ0, 7ΛHe, 9ΛLi, 10ΛBe, 12ΛB, 52ΛV – Analyses are in progress • Matrix tuning • Blind analysis • Efficiencies E05-115 collaboration Backup New challenging experiment 1m Λ, Σ0 Elementary process Energy scale calibration 12ΛB Consistency check 27ΛMg, 48ΛSc Deformation 208ΛTl Single particle energy eγ* p n Λ target nucleus K+ New challenging experiment 1m Λ, Σ0 Elementary process Energy scale calibration 12ΛB Consistency check 27ΛMg, 48ΛSc Deformation 208ΛTl Single particle energy πp n Λ target nucleus 4ΛH Charge symmetry breaking New challenging experiment 1m Λ, Σ0 Design and setup Elementary process Energy scale calibration 12ΛB Consistency check 27ΛMg, 48ΛSc Deformation 208ΛTl Single particle energy • 3-D magnetic field calculation • Monte Carlo simulation Experimental operation Analyses • Energy scale calibration • Tracking 4ΛH Charge symmetry breaking Background events in the HKS REAL DATA x [cm] 9Be SIMULATION , 38.4 [μA] KDC1 KDC2 y [cm] KDC1 KDC2 z [cm] • 52Cr e+ target – Luminosity ( 1/10 ) – Worse S/N – Tracking is not easy Tracking efficiency and residual σ ~ 160 μm σ ~ 350 μm Plane efficiency Tracking residual 52Cr(e,e’K+)52 ΛV Nbind~870 Hit wire selection 52Cr REAL DATA Target Black : hit wires Blue : selected wires Red : track CUT REAL DATA CUT CH2 Target Compared to the conventional code Number of K+ +130% Analysis time – 30% 軽い核のミッシングマス JLab E05-115, Carbon (112mg/cm2) 数、分解能 Energy scale calibration conversion e, K+ Mx – MΛ < 100 keV/c2 トラッキング困難 CH2 Target H2O Target REAL DATA Black : hit wires Blue : selected wires Red : track REAL DATA 52LV Singles rate summary HKS Up to ~30 [MHz] HKS trigger ~ 10[kHz] HES Up to ~15 [MHz] COIN ≤ 2.0 [kHz] HES trigger ~ a few[MHz] HKS-HES Collaboration Meeting, T.Gogami 29 B.G. mix rate (real data) b a B.G mix rate = * hks ntulpe HKS-HES Collaboration Meeting, T.Gogami 𝑏 𝑎+𝑏 30 e+ simulation SIMULATION • To see 1. Number of event 2. Angle & momentum of e+ generated in target HKS-HES Collaboration Meeting, T.Gogami 31 Spectroscopic experiment by the (e,e’K+) reaction Feynman diagram e p e u u d γ* u K+ –s s u Λ d e’-Spectrometer eγ* p n Λ target nucleus ~ 1990’s The (K-,π-) , (π+,K+) reactions • Energy resolution ~ a few MeV • n Λ 2012/9/14 pe’ e + p ➝ e’ + K+ + Λ Missing Mass HHY K+ K+-Spectrometer pK+ 2000~ The (e,e’K+) reaction • Energy resolution ~0.5 MeV • pΛ JPS meeting in Kyoto , Toshi Gogami 32 Background events in the HKS REAL DATA x [cm] y [cm] 9Be , 38.4 [μA] SIMULATION KDC1 KDC2 KDC1 KDC2 z [cm] e+ • ~2.24 ~4.94 52Cr target – Luminosity ( 1/10 ) – Worse S/N – Tracking is not easy 10 12 B histograms Be, Λ Λ FWHM~0.9 MeV sΛ FWHM~0.9 MeV sΛ pΛ NsΛ~190 NsΛ~530 Experimental motivation • JLab E05-115 (2009, Hall-C) – Elementary processes (Λ,Σ0) – 7ΛHe[1], 9ΛLi, 10ΛBe • ΛN charge symmetry breaking • ΛN-ΣN coupling – 12 B Λ • Consistency check with the past experiments • Check analysis progress – 52 V Λ • 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, 012502 (2013) Detectors & Trigger HES K+ e- HES trigger (TOF1x2) ~2000 kHz TOF walls (Plastic scintillators) HKS p, π+ HKS trigger (TOF1x2x3) x Chrenkov Cherenkov detectors ~10 kHz • Aerogel (n=1.05) • Water (n=1.33) Coincidence trigger Drift chambers HES x HKS < 2 kHz 2012/10/6 Core2Core in Barcelona, Toshi Gogami 36 52Cr(e,e’K+)52 ΛV f p 数 d s Mixed event analysis をやる Electro-production of K+Λ JLab E05-115 experiment by the (e,e’K+) reaction Small Q2 ( ~0.01 [GeV/c]2 ) almost real photon Real photon 2013/3/27 JPS meeting in Hiroshima , Toshi Gogami 38 An importance of measurement of K+Λ production at forward angles Real photon Q2 = 0 [ GeV/c ]2 P.Bydzovsky and T.Mart, Phys. Rev. C 76, 065202 (2007) At forward angles 2013/3/27 – Data show lack of consistency – We can access θKcm ~ 15 deg JPS meeting in Hiroshima , Toshi Gogami 39 Λ, Σ0 from polyethylene ( CH2 )target 2013/3/27 JPS meeting in Hiroshima , Toshi Gogami 40 Λ, Σ0 from CH2 target JLab E05-115 CH2, ~ 450 [mg/cm2] ~ 2.0 [μA] ~ 38 [hours] p(e,e’K+)Λ ~1.8MeV (FWHM) Δm = 19 ± 17 keV/c2 p(e,e’K+)Σ0 ~1.8MeV (FWHM) Δm = 73 ± 47 keV/c2 2013/3/27 JPS meeting in Hiroshima , Toshi Gogami 41 Cross sections Preliminary 85 ± 13 ±34 Preliminary 200 ± 16 ± 91 γ(*) + p K+ + Λ γ(*) + p K+ + Σ0 SAPHIR : K.H. Glander et al. , Eur. Phys. J. A 19, 251-273 (2004) CLAS : R. Bradford et al. , Phys. Rev. C 73, 035202 (2006) 2013/3/27 JPS meeting in Hiroshima , Toshi Gogami 42 Cross sections Preliminary 85 ± 13 ±34 Preliminary 200 ± 16 ± 91 γ(*) + p K+ + Λ γ(*) + p K+ + Σ0 SAPHIR : K.H. Glander et al. , Eur. Phys. J. A 19, 251-273 (2004) CLAS : R. Bradford et al. , Phys. Rev. C 73, 035202 (2006) JLab E94-107 : P. Markoviz et al. , Proceedings of SENDAI08 (2009) JLab E91-016 : F. Dohrmann et al. , arXiv 0707.3059v2 (2007) 2013/3/27 JPS meeting in Hiroshima , Toshi Gogami 43 Q2 dependence (JLab E05-115) JLab E05-115, CH2 target W = 1.93 GeV θCM = 17 degrees 実光子 (SAPHIR) 2013/3/27 JPS meeting in Hiroshima , Toshi Gogami 44 Apply to u,v-layer v v’-layer Selective region determined by 1X and 2X Convert x x’-layer 2012/9/14 Applied to uu’ and vv’ layers , too. JPS meeting in Kyoto , Toshi Gogami 45 Hit wires event display (2) v v’ u u’ v v’ u u’ particle particle x x’ x x’ • GREEN region Selective region • RED markers & lines Selected hit wires • BLACK markers & lines Rejected hit wires 2012/9/14 JPS meeting in Kyoto , Toshi Gogami 46 Detectors & Trigger HES K+ eTOF walls (Plastic scintillators) HKS p, π+ Cherenkov detectors • Aerogel (n=1.05) • Water (n=1.33) Drift chambers 2012/10/6 Core2Core in Barcelona, Toshi Gogami 47 Detectors & Trigger HES K+ e- HES trigger (TOF1x2) ~2000 kHz TOF walls (Plastic scintillators) HKS p, π+ HKS trigger (TOF1x2x3) x Chrenkov Cherenkov detectors ~10 kHz • Aerogel (n=1.05) • Water (n=1.33) Coincidence trigger Drift chambers HES x HKS < 2 kHz 2012/10/6 Core2Core in Barcelona, Toshi Gogami 48 Coincident K+ Identification (OFF-LINE) Cherenkov selection Water (n=1.33) Coincidence time selection Aerogel (n=1.05) ( e,e’p ) K+ + π CUT ( e,e’K+ ) CUT CUT CUT CUT CUT p ( e,e’π+ ) = HKST - HEST p cut π+ cut Coincidence of (e,e’K+) selection mK2 selection Coincident K+ : ~90% ( π+ : < 1% , p : < 2% ) 2012/10/6 Core2Core in Barcelona, Toshi Gogami 49 10 12 B histograms Be, Λ Λ FWHM~0.9 MeV sΛ FWHM~0.9 MeV sΛ pΛ NsΛ~190 NsΛ~530
© Copyright 2024 ExpyDoc
