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加速器を用いた ハドロン物理実験 K. Ozawa (KEK). 内容 原子核の性質 – ストレンジネスで探る原子核内部 – ハドロンーハドロン相互作用 – 原子核媒質とメソン 核子(バリオン)の中身 – ストレンジバリオン – Di-quark 相関 2013/10/30Hadron Experiment,

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Presentation on theme: "加速器を用いた ハドロン物理実験 K. Ozawa (KEK). 内容 原子核の性質 – ストレンジネスで探る原子核内部 – ハドロンーハドロン相互作用 – 原子核媒質とメソン 核子(バリオン)の中身 – ストレンジバリオン – Di-quark 相関 2013/10/30Hadron Experiment,"— Presentation transcript:

1 加速器を用いた ハドロン物理実験 K. Ozawa (KEK)

2 内容 原子核の性質 – ストレンジネスで探る原子核内部 – ハドロンーハドロン相互作用 – 原子核媒質とメソン 核子(バリオン)の中身 – ストレンジバリオン – Di-quark 相関 2013/10/30Hadron Experiment, K. Ozawa2

3 J-PARC (Japan Proton Accelerator Research Complex) Tokai, Japan 50 (30) GeV Synchrotron (15  A) 400 MeV Linac (350m) 3 GeV Synchrotron (333  A) Material and Biological Science Facility World-highest beam intensity : ~1 MW x10 of BNL-AGS, x100 of KEK-PS Neutrino Facility Hadron Hall 60m x 56m 2013/10/303Hadron Experiment, K. Ozawa

4 Nuclear & Hadron Physics at J-PARC  N Z ,  Hypernuclei ,  Hypernuclei Strangen ess 0 Hypernuclei -2 Proton Beam K1.8 KL K1.1BR High p (not yet) SKS K1.8BR K1.1 d u u d s Pentaquark  +  He 6 Free quarks Bound quarks Why are bound quarks haevier ? Quark Mass without Mass Puzzle Kaonic nucleus Kaonic atom X ray K−K− Implantation of Kaon and the nuclear shrinkage K meson 2013/10/304Hadron Experiment, K. Ozawa

5 KL K1.1BR North side South side High Momentum SKS K1.8BR 2013/10/30Hadron Experiment, K. Ozawa5

6 SKS Spectrometer Q10 Q11 Q12 Q13 D4 2013/10/30Hadron Experiment, K. Ozawa6

7 核構造とストレンジネス 2013/10/30Hadron Experiment, K. Ozawa7

8 原子核構造 偶-偶核の第一励起準位エネルギー (閉殻構造、魔法数の存在) 1 体ポテンシャルによる励起準位 調和振動子 井戸型 ウッド・サク ソン 励起準位(調和振動子、井戸型) 2013/10/30Hadron Experiment, K. Ozawa8

9 ストレンジネス 1 体ポテンシャルによる励起準位 PRC 64 (2001) > U  = - 28 MeV (c.f. U N = -50 MeV) ストレンジネスは、 Pauli Blocking を受 けないので、原子核の中に置ける。 実際に、殻構造があることを実証 2013/10/30Hadron Experiment, K. Ozawa9 束縛エネルギーは、違っていた。

10 ストレンジネス束縛エネル ギー PRC 64 (2001) > U  = - 28 MeV (c.f. U N = -50 MeV) 束縛エネルギーの違いがもたらす物理 Experimental input to models Schaffner-Bielich, NP A804 (2008). Baryon fraction in neutron star One example… More experimental information on  N,  N, ,  N interactions are awaited. 2013/10/30Hadron Experiment, K. Ozawa10

11 Precise measurements of  N (E13)  spectroscopy for light hyper nuclear using (K -,  - ) reaction at p K =1.5 (or 1.1) GeV/c. Physics:  N interaction – Charge symmetry breaking in  N interaction 4  He : Large CSB is suggested – sd-shell hypernuclei for A-dependence of  N interaction 19  F : The first sd-shell hypernuclei – Confirm  N spin-dependent forces and study  N-  N coupling force 10  B and 11  B Physics: g-factor of  in nucleus – Spin-flip B(M1) measurement for g  in a nucleus 7  Li : Least ambiguities and most reliable. Hyper Ball-J is almost ready and we will take the first experimental data soon. 2013/10/30Hadron Experiment, K. Ozawa11 Beam

12  interaction (E07) At KEK-PS E373, there are ~ 700  stops and one NAGARA event is observed. –Δ B   = 1.01±0.20 MeV for  6  He At J-PARC, S=-2 nuclear chart is studied by ~10 2  Z via 10 4  - -stopping events. –  B  of several nuclides will provide definitive information on  interaction and structure of S=-2 nuclei. 2013/10/30Hadron Experiment, K. Ozawa12 Experimental Method (Nuclear Emulsion) The experiment is under preparations and it will be performed in the end of this year or early next year.

13  N interaction (E05) Discovery of  -hyper nucleus using 12 C(K -,K + ) reaction – 12  Be Missing mass spectroscopy – High resolution Originally, 3 MeV(FWHM) 1.5 MeV will be achieved using a new spectrometer Experiment will start in 2015 and we can expect more than 200 events of  -hyper nucleus – Precise spectroscopy 2013/10/30Hadron Experiment, K. Ozawa13 Expected Spectrum (Will be improved using a new spectrometer)

14 ハドロンーハドロン相互作用 2013/10/30Hadron Experiment, K. Ozawa14

15 バリオンーバリオン相互作用 Example : 陽子・中性子・重陽子の性質 図は、八木浩輔・原子核物理学 中性子・陽子散乱の角分布 2013/10/30Hadron Experiment, K. Ozawa15 ストレンジネスを含む相互作用の違いの起源はどこ に? 中性子・陽子の相互作用の研究は、 散乱実験 これはストレンジネスでも可能 2体束縛状態(重陽子)の研究 ストレンジネスセクターに存在しない。

16  N Scattering (E40) Differential cross section of   p and   p scattering with 100 times larger statistics Motivation: See “quark-Pauli effect” 2013/10/30Hadron Experiment, K. Ozawa16 meson exch quark + meson exch Evaluation of quark Pauli effect and understanding the origin of the hard core of the nuclear force  + p (quark Pauli) Hyperon production 1.3 GeV/c  +- p -> K +  +- reaction  +- track not directly measured Measure proton momentum vector -> kinematically complete New experimental techniques with MPPC and Fiber Tracker will be used

17 メソン-バリオン相互作用( KN, E15 ) 17 Physics motivation Experimental setup Experimental scheme Experiment is on-going 2013/2/11J-PARC Future 2013, K. Ozawa

18 Results of an engineering run XY planeYZ plane Liquid 4 He inside Target-image together with material around has been reconstructed by the CDS Charged particles from the target have been successfully identified by the CDS 18 p  - invariant-mass spectra reconstructed by the CDS  ~10,000  s have been accumulated 2013/10/30Hadron Experiment, K. Ozawa  CDS and Liquid Helium target system successfully worked  Ready to explore kaonic- K1.8BR  Data Taking in this May!

19 19 E27: Search for “K  pp” bound state in the d(  ,K  )X reaction “K  pp” is produced through  * doorway in the d(  ,K + ) reaction Semi-exclusive measurement by Range Counter Array (RCA) in order to suppress quasi-free B.G. – K  pp   p 1,   p 2   – K  pp   p 1,    (  )  p 2    –   d   * K + p 1s,  *   ,    p 2   n p K - pp d Λ* π+π+ K+K+ RCA K+K+ p 2013/10/30Hadron Experiment, K. Ozawa Missing mass d(π +,K + ) [GeV/c 2 ] Mom proton >350MeV/c counts (/3M beam ・ 10days ) Expected point by FINUDA, DISTO Data already collected and results will be reported soon.

20 原子核媒質とメソン 2013/10/30Hadron Experiment, K. Ozawa20

21 Mass [GeV] 媒質からの励起状態としてのハド ロン 2013/10/30Hadron Experiment, K. Ozawa21 NG ボソンとして の擬スカラー中 間子 ( J p =0 - ) 構成子クォー クの質量を獲 得 カイラル対称性の自発的 破れに伴う質量の獲得 π 中間子が異常に軽い ( M  ~ 130 MeV/c 2 )こと は、対称性の自発的破れ に伴う南部ゴールドスト ンボソンと理解 実際にカイラル対称性は 破れている。 – カイラルパートナーに 質量差があることが知 られている 媒質中での中間子の測定 原子核媒質の性質の測定 原子核 - 中間子相互作用の測定

22  束縛状態 2013/10/30 Hadron Experiment, K. Ozawa 22 Large overlap of wave function Sensitive to -nucleus strong interaction potential Measure binding energy can be converted to this b1 information

23 Exp. Results 2013/10/30 Hadron Experiment, K. Ozawa 23 K. Suzuki et al., Phys. Rev. Let., 92(2004)  bound state is observed in Sn(d, 3 He) pion transfer reaction at GSI. Reduction of the chiral order parameter, f*  () 2 /f  2 =0.64 at the normal nuclear density ( =  0 ) is indicated. Experiment is continued at RIKEN and positive results are already obtained.

24 Other Pseudo Scalar Meson:  2013/10/30Hadron Experiment, K. Ozawa LOI by K. Itahashi et. al Calc. by H. Nagahiro, D. Jido, S. Hirenzaki et. al Forward neutron is detected. missing mass distribution is measured. In addition, measurements of invariant mass of N* decay Simulation 24

25 Other Pseudo Scalar Meson:  GSI 2013/10/30Hadron Experiment, K. Ozawa25 Reaction is similar with pionic atom experiment. Theoretical calculation by H. Nagahiro

26 反クォーク・クォーク凝縮量 反クォーク・クォーク凝縮量と関係した測定量 – ベクトル中間子や軸性ベクトル中間子の質量分布 – Weinberg type sum rule – たとえば、自由空間中で、  粒子の崩壊からの分布の 測定がある。( ALEPH, Phys. Rep. 421(2005) 191 ) – 自由空間以外での測定は、実験的に難しい 2013/10/30Hadron Experiment, K. Ozawa26 Hatsuda, Koike and Lee, Nucl. Phys. B394 (1993) 221 Kapusta and Shuryak, Phys. Rev. D49 (1994) 4694

27 Example: sum rule e.g. Weinberg type QCD sum rule Hatsuda, Koike and Lee, Nucl. Phys. B394 (1993) 221 Kapusta and Shuryak, Phys. Rev. D49 (1994) /10/30 Hadron Experiment, K. Ozawa 27 ALEPH, Phys. Rep. 421(2005) 191

28 さらに、反クォーク・クォーク凝 縮量 QCD sum rule をベクトル中間子の質量分布に 適用し、凝縮量と関係づけられると示唆 実験的には、 – ベクトル中間子質量分布の測定は可能 – 原子核中や高温ハドロン物質中での測定も可能 内包する凝縮量の違いを反映する 質量獲得モデルや “QCD 媒質 ” 状態予想の検証 – 自由空間以外でのベクトル中間子の質量分布測定 が基礎情報として重要 2013/10/30Hadron Experiment, K. Ozawa28 Hatsuda and Lee, Phys. Rev. C46 (1992) R34

29 KEK-PS E325 実験へ 原子核密度に対する面白い予想の存在 – 凝縮量と質量分布の関係と以下の仮定を基に予想 質量分布の形 – 凝縮量の変化の効果をポール位置の変化に集約 核子内の凝縮量の評価 凝縮量は、密度に線形に変化 – 原子核中で、 18 %( ρ, ω )と 1.8% ( φ )の質量変化を予測 実験的に検証可能 – 原子核中での崩壊により質量分布を測定 – 終状態相互作用を避けるために電子対崩壊を選択 – バックグランドや ρ-ω 干渉に関する不定性を避けるため、 φ 中間子に対して測定 φ 中間子の幅は狭い( 4.3 MeV/c 2 )。質量変化が測定しやすい。 あらわなハドロン相互作用の効果は小さい。 – e.g. Binding energy of  N is 1.8 MeV (Phys. Rev. C 63(2001) R) 2013/10/30Hadron Experiment, K. Ozawa29 Hatsuda and Lee, Phys. Rev. C46 (1992) R34 Hatsuda and Kunihiro, Nucl. Phys. B387 (1992) 715

30 KEK-PS E325 実験の概要 2013/10/30Hadron Experiment, K. Ozawa30 12 GeV proton induced. p+A   + X Electrons from  decays are detected. Target Carbon, Cupper 0.5% rad length KEK E325

31 Clear measurements of  meson at KEK-PS. 2013/10/3031 R. Muto et al., PRL 98(2007) Indication of QCD-originated mass modification! Cu  <1.25 (Slow) e + e - invariant mass Decays inside nucleus Decays outside nucleus  meson has mass modification Modification is shown as an Excess  meson has NO mass modification Blue line shows expected line shape including all experimental effects wo mass modification The only one measurement on medium modification of  meson. Hadron Experiment, K. Ozawa

32 322013/10/30 Target/Momentum dep.  <1.25 (Slow) 1.25<  <1.75 Only one momentum bin shows a mass modification under the current statistics. To see clear mass modification and establish QCD-originated effects, significantly larger statistics are required. e + e - invariant mass Two nuclear targets: Carbon & Copper Inside-decay increases in large nucleus Momentum bin Slowly moving  mesons have larger chance to decay inside nucleus Same as previous slide Excess Hadron Experiment, K. Ozawa

33 KEK-PS E325 で得られたもの 原子核中での φ 中間子の質量分布変化を示唆する データ 得られた分布を φ 中間子の質量ピーク位置の変化 として解釈すると、 3% の変化 初田 -Lee 予想と Consistent だが、偶然かもしれない。 – 核子内の 凝縮量は、非常に小さいという Lattice の 計算( H. Ohki et. al, Phys. Rev. D 78(2008) ) – 密度に対する凝縮量の線形近似 – 中間子生成過程、 中間子崩壊点の密度の不定性 2013/10/30Hadron Experiment, K. Ozawa33

34 次に、何を目指すか? KEK-PS E325 の結果の Confirm – 世界的にも、他に φ 中間子の結果は得られていな い。 原子核密度における質量分布の確立 – 凝縮量との関係に対する議論に耐えられるデータ – 生成過程、密度分布などの不定性の小さいデータ 単なる質量分布を超えた測定 – 媒質中で質量に対応するものは、エネルギーと運 動量の分散関係 2013/10/30Hadron Experiment, K. Ozawa34

35 J-PARC での実験の目標 2013/10/3035 Pb Proton A clear shifted peak needs to be identified to establish QCD-originated effects Momentum Dependence E325 results Extrapolate Hadron Experiment, K. Ozawa 凝縮量の評価を可能にする高統計測定

36 さらに、 2013/10/30Hadron Experiment, K. Ozawa36 Pb  Modified  [GeV/c 2 ]  from Proton Invariant mass in medium         p dep. Dispersion relation

37 Experimental set up 2013/10/30Hadron Experiment, K. Ozawa37 Cope with per spill beam intensity (x10) Extended acceptance (90  in vertical) (x5) Increase cross section (x2) Construct a new beam line and new spectrometer Deliver per spill proton beam Primary proton (30GeV) beam New high momentum beam line

38 Detector components 2013/10/ x x x300 Position resolution of 100  m is achieved GEM Tracker HBD (Hadron-Blind Cherenkov detector ) Both detectors based on Gas Electron Multiplier (GEM) technology Recently, we succeed making a proto-type which meets our experimental requirements. Now, we are preparing a mass production of detectors. Key Technology: CsI evaporated GEM as a photo cathode Q.E. of 40% is achieved Hadron Experiment, K. Ozawa

39  bound state? 2013/10/30 Hadron Experiment, K. Ozawa s s u u d K+ Λ Φ p u d s u s  p -> K +  pp ->  39 Mass shift of  in nucleus can produce a bound state? Production Detection J. Yamagata-Sekihara, D. Cabrera, M. J. Vicednte-Vacas, S. Hirenzaki; 'Formation of Φ mesic nuclei'; Progress of Theoretical Physics 124, (2010).

40 E26: Omega in nucleus 2013/10/3040       n   A   + n+X  00 Measurements of  meson in nucleus Production of  is also measured Focus on low momentum  meson Construct Neutron counter Gamma Detector Beam Momentum is 2.0 GeV/c It can be done at K1.8 and also at new high momentum beam line Hadron Experiment, K. Ozawa H. Nagahiro et al, Calculation for 12 C(  , n) 11 B  Missing Mass (Bound state?) Invariant Mass

41 ハドロン内部構造 2013/10/30Hadron Experiment, K. Ozawa41

42 アイソスピン対称性・クォークモ デル 陽子: | 1/2, + 1/2 >, S = 0 中性子:| 1/2, - 1/2 >, S = 0 π 中間子: I=1 の 3 重項, S = 0 陽子: | 1/2, + 1/2 >, S = 0 中性子:| 1/2, - 1/2 >, S = 0 π 中間子: I=1 の 3 重項, S = 0  + p,  - p 反応の断面積 Particle Data Book, Phys. Let. B667(2008), 1 Baryon 但、クォークの数を3つとする原理的理由はない。 2013/10/30Hadron Experiment, K. Ozawa42

43 E19:Penta quark - results 2010 data No peak of   was observed. U.L. (90%CL) 0.26  b/sr (2 - 14°) in 1.51 - 1.55GeV/c 2 U.L.(90%CL) of     0.72 MeV (1/2 + ) 3.1 MeV (1/2  ) Search for the Θ + via the p+π - →K - +X Reaction at 1.97GeV/c PRL 109 (2012) PRL published Updated data with higher beam momentum exists. See Dr. Naruki’s talk. 2013/10/3043Hadron Experiment, K. Ozawa

44 H dibaryon search (E42) The observation of several double-  hypernuclear events in nuclear emulsion suggests that the H-dibaryon is very closely bound or unbound relative to 2m . Some experimental results show an enhancement just above 2m  mass (~ 2250 MeV/c 2 ). – J.K. Ahn et al., PLB 444 (1998) 267 – C.J. Yoon et al., PRC 75 (2007) (R) Weakly-bound : H ->  p  Virtual state :  threshold effect Precise measurements of  and  p productions in 12 C(K -, K + ) reactions are proposed. – Forward K spectrometer and a time projection chamber around the target is used. 2013/10/30Hadron Experiment, K. Ozawa44 Expected spectrum for a virtual state Experimental setups

45 クォーク・反クォーク ポテン シャル Harmonic Oscillator 型 Potential の励起状態 Coulomb Potential (Positronium) との比較 Charmonium ( c-c ) の励起状態 Martin and Shaw, Particle Physics q-q ポテンシャル 実線: -a/r + br 、破線 : a ・ ln(br) 2013/10/30Hadron Experiment, K. Ozawa45

46 Diquarks Baryons Mesons L L M 2 (GeV 2 ) M 2 ∝ 1.1L Baryons as well as Mesons seem to be well described by a Rotating String Configuration with a universal string tension.

47 Emergent Diquarks Baryons as well as Mesons seem to be well described by a Rotating String Configuration with a universal string tension. “diquark” in low-lying modes qq q

48 Heavy quark baryon When single quark picture is still a good picture, excited states are degenerated. If Cqq (q=u,d) system is considered as C and di-quark correlations, orbital motion of is lowered due to the collectivity of the di-quark motion. Spin correlations between light quarks give additional level separations. 2013/10/3048 : orbital motion  : di-quark correlation Hadron Experiment, K. Ozawa Measurements of all levels are important Level pattern tell us: Mass of di-quark Strength of di-quark correlation Spin dependent correlation between light quarks

49 Missing mass Spectroscopy Large Acceptance, Multi-Particle – K,  from D 0 decays – Soft  from D* - decays – (Decay products from Y c *) High Resolution High Rate – SFT/SSD op. >10M/spill at K Tm Dipole H 2 TGT Beam   PID   DC TOF PID  DC High rate Trackers (Fiber, SSD) LAMPS Use forward D mesons production No Bias measurements up to 3GeV/c 2 of Charmed Baryon mass 2013/10/30Hadron Experiment, K. Ozawa49

50 Signal: 1 nb/Yc* :~1000 events BG: 1.8 mb (JAM)  c 1/2 +  c (2455) 1/2 +  c (2520) 3/2 +  c (2800) ? ?  c (2595) 1/2 -  c (2625) 3/2 -  c (2880) 5/2 +  c (2940) ? ? DN  c (GeV/c 2 ) D*N  c 2.8 Expected Spectrum in the ( ,D* - ) reaction cc  c (2455)  c (2520)  c (2625)  c (2765)  c (2880)  c + 0.8GeV Missing Mass (GeV/c 2 )  c DND*N  c (2595)  c (2800)  c (2940)

51 Summary Several experiments are being performed and prepared at J-PARC to investigate hadron interactions, nuclear medium effects and internal structure of hadrons. Currently, strangeness nuclear physics and Kaon bound system are intensively studied. In near future, meson properties in nucleus and level structure of charmed baryons will be measured. 2013/10/3051Hadron Experiment, K. Ozawa


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