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加速器を用いた ハドロン物理実験 K. Ozawa (KEK).

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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)."— Presentation transcript:

1 加速器を用いた ハドロン物理実験 K. Ozawa (KEK)

2 Hadron Experiment, K. Ozawa
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 2013/10/30 Hadron Experiment, K. Ozawa

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

4 Hadron Experiment, K. Ozawa
Nuclear & Hadron Physics at J-PARC L,X N Z L, S Hypernuclei LL, X Hypernuclei Strangeness Hypernuclei -1 -2 d u s Pentaquark + He 6 K1.8 KL K1.1BR High p (not yet) SKS K1.8BR K1.1 Implantation of Kaon and the nuclear shrinkage K meson Free quarks Bound quarks Why are bound quarks haevier? Quark Mass without Mass Puzzle On the other hand, the hadron experimental hall looks like this. ● Proton beam comes here and various kaon beam lines are prepared, where K=1.8 means kaons with momentum of 1.8 GeV/c. ● At SKS, hypernuclear spectroscopy will be performed for a variety of nuclei. ● In particular, searches for double hypernucleus and pentaquark are the highlights in here. ● In this beamline, kaon implantation is planned. When kaon is implanted inside the nucleus, there is a possibility that high density matter is created. ● Kaonic atom and kaonic nucleus will be studied. ● This beam line is the neutral kaon line to study CP violation, and ● this line is for T-violation experiment. ● Finally, this line, which is not yet completed, is dedicated to the study of chiral symmetry, namely, the mass generation mechanism of bound quarks. Kaonic nucleus Kaonic atom Xray K− Proton Beam 2013/10/30 Hadron Experiment, K. Ozawa 4

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

6 Hadron Experiment, K. Ozawa
SKS Spectrometer Q13 Q12 K1.8 Beam Spectrometer 実験エリアの現状 2009年秋からビームタイム開始 D4 Q11 Q10 2013/10/30 Hadron Experiment, K. Ozawa 6

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

8 Hadron Experiment, K. Ozawa
原子核構造 調和振動子 井戸型 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) ウッド・サクソン 2013/10/30 Hadron Experiment, K. Ozawa 1体ポテンシャルによる励起準位 励起準位(調和振動子、井戸型)

9 Hadron Experiment, K. Ozawa
ストレンジネス 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 PRC 64 (2001) -> UL = - 28 MeV (c.f. UN = -50 MeV) 束縛エネルギーは、違っていた。 2013/10/30 Hadron Experiment, K. Ozawa 1体ポテンシャルによる励起準位

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

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

12 Hadron Experiment, K. Ozawa
LL interaction (E07) At KEK-PS E373, there are ~ 700 X stops and one NAGARA event is observed. ΔBLL = 1.01±0.20 MeV for L6LHe At J-PARC, S=-2 nuclear chart is studied by ~102 LLZ via 104 X --stopping events. DBLL of several nuclides will provide definitive information on LL interaction and structure of S=-2 nuclei. Experimental Method (Nuclear Emulsion) The experiment is under preparations and it will be performed in the end of this year or early next year. 2013/10/30 Hadron Experiment, K. Ozawa

13 Hadron Experiment, K. Ozawa
XN interaction (E05) Expected Spectrum (Will be improved using a new spectrometer) Discovery of X-hyper nucleus using 12C(K-,K+) reaction 12XBe 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 X-hyper nucleus Precise spectroscopy 2013/10/30 Hadron Experiment, K. Ozawa

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

15 バリオンーバリオン相互作用 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
図は、八木浩輔・原子核物理学 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。 Example: 陽子・中性子・重陽子の性質 中性子・陽子散乱の角分布 2013/10/30 Hadron Experiment, K. Ozawa

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

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

18 Results of an engineering run
XY plane YZ plane Liquid 4He 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 CDS and Liquid Helium target system successfully worked Ready to explore K1.8BR Data Taking in this May! pp- invariant-mass spectra reconstructed by the CDS L 2013/10/30 Hadron Experiment, K. Ozawa ~10,000 Ls have been accumulated

19 E27: Search for “K-pp” bound state in the d(p+,K+)X reaction
“K-pp” is produced through L* doorway in the d(p+,K+) reaction Semi-exclusive measurement by Range Counter Array (RCA) in order to suppress quasi-free B.G. K-pp ® L p1, L ® p2 p- K-pp ® S0 p1, S0 ® (Lg) ® p2 p- g p+d ® L* K+ p1s, L* ® S p, S+ ® p2 p0 π+ K+ Λ* n d K-pp p K+ p RCA Momproton>350MeV/c Expected point by FINUDA, DISTO Data already collected and results will be reported soon. counts (/3M beam・10days ) 2013/10/30 Hadron Experiment, K. Ozawa Missing mass d(π+,K+) [GeV/c2]

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

21 Hadron Experiment, K. Ozawa
媒質からの励起状態としてのハドロン Mass [GeV] 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(Mp ~ 130 MeV/c2 )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 構成子クォークの質量を獲得 NGボソンとしての擬スカラー中間子 (Jp=0-) 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 2013/10/30 Hadron Experiment, K. Ozawa

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

23 Hadron Experiment, K. Ozawa
Exp. Results K. Suzuki et al., Phys. Rev. Let., 92(2004) bound state is observed in Sn(d, 3He) pion transfer reaction at GSI. Reduction of the chiral order parameter, f*p(r)2/fp2=0.64 at the normal nuclear density (r = r0 ) is indicated. Experiment is continued at RIKEN and positive results are already obtained. 2013/10/30 Hadron Experiment, K. Ozawa

24 Other Pseudo Scalar Meson: h
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. Simulation In addition, measurements of invariant mass of N* decay 2013/10/30 Hadron Experiment, K. Ozawa

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

26 Hadron Experiment, K. Ozawa
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、t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 Hatsuda, Koike and Lee, Nucl. Phys. B394 (1993) 221 Kapusta and Shuryak, Phys. Rev. D49 (1994) 4694 2013/10/30 Hadron Experiment, K. Ozawa

27 Hadron Experiment, K. Ozawa
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) 4694 ALEPH, Phys. Rep. 421(2005) 191 2013/10/30 Hadron Experiment, K. Ozawa

28 Hadron Experiment, K. Ozawa
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 Hatsuda and Lee, Phys. Rev. C46 (1992) R34 2013/10/30 Hadron Experiment, K. Ozawa

29 Hadron Experiment, K. Ozawa
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/c2 )。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 fN is 1.8 MeV (Phys. Rev. C 63(2001) R) Hatsuda and Lee, Phys. Rev. C46 (1992) R34 Hatsuda and Kunihiro, Nucl. Phys. B387 (1992) 715 2013/10/30 Hadron Experiment, K. Ozawa

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

31 Clear measurements of f meson at KEK-PS.
The only one measurement on medium modification of f meson. R. Muto et al., PRL 98(2007) Cu bg<1.25 (Slow) e+e- invariant mass Decays outside nucleus Decays inside nucleus meson has NO mass modification Blue line shows expected line shape including all experimental effects wo mass modification meson has mass modification Modification is shown as an Excess Indication of QCD-originated mass modification! 2013/10/30 Hadron Experiment, K. Ozawa

32 Hadron Experiment, K. Ozawa
Target/Momentum dep. bg<1.25 (Slow) 1.25<bg<1.75 Two nuclear targets: Carbon & Copper Inside-decay increases in large nucleus Momentum bin Slowly moving f mesons have larger chance to decay inside nucleus 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. Same as previous slide Excess 2013/10/30 e+e- invariant mass Hadron Experiment, K. Ozawa

33 Hadron Experiment, K. Ozawa
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<ss>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 2013/10/30 Hadron Experiment, K. Ozawa

34 Hadron Experiment, K. Ozawa
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 2013/10/30 Hadron Experiment, K. Ozawa

35 Hadron Experiment, K. Ozawa
J-PARCでの実験の目標 A clear shifted peak needs to be identified to establish QCD-originated effects Momentum Dependence Pb E325 results Extrapolate Proton 凝縮量の評価を可能にする高統計測定 2013/10/30 Hadron Experiment, K. Ozawa

36 Hadron Experiment, K. Ozawa
さらに、 Pb f Modified f [GeV/c2] f p dep. f from Proton Invariant mass in medium Dispersion relation 2013/10/30 Hadron Experiment, K. Ozawa

37 Hadron Experiment, K. Ozawa
Experimental set up Construct a new beam line and new spectrometer Cope with 1010 per spill beam intensity (x10) Extended acceptance (90 in vertical) (x5) Increase cross section (x2) Deliver 1010 per spill proton beam Primary proton (30GeV) beam New high momentum beam line 2013/10/30 Hadron Experiment, K. Ozawa

38 Hadron Experiment, K. Ozawa
Detector components HBD (Hadron-Blind Cherenkov detector ) GEM Tracker 100x x x300 Key Technology: CsI evaporated GEM as a photo cathode Q.E. of 40% is achieved Position resolution of 100m is achieved 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. 2013/10/30 Hadron Experiment, K. Ozawa

39 Hadron Experiment, K. Ozawa
E29: f bound state? Mass shift of f in nucleus can produce a bound state? Production pp -> ff Detection fp -> K+L s u d K+ Λ Φ p J. Yamagata-Sekihara, D. Cabrera, M. J. Vicednte-Vacas, S. Hirenzaki; 'Formation of Φ mesic nuclei'; Progress of Theoretical Physics 124, (2010).  2013/10/30 Hadron Experiment, K. Ozawa

40 Hadron Experiment, K. Ozawa
E26: Omega in nucleus Measurements of w meson in nucleus Production of w is also measured Focus on low momentum w meson g p w p0 n p-A   + n+X  p0g H. Nagahiro et al, Calculation for 12C(p-, n)11Bw Missing Mass (Bound state?) 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 Invariant Mass 2013/10/30 Hadron Experiment, K. Ozawa

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

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 Baryon 但、クォークの数を3つとする原理的理由はない。 p+p, p-p反応の断面積 Particle Data Book, Phys. Let. B667(2008), 1 2013/10/30 Hadron Experiment, K. Ozawa

43 E19:Penta quark - results
2010 data Search for the Θ+ via the p+π-→K-+X Reaction at 1.97GeV/c No peak of Q+ was observed. U.L. (90%CL) 0.26mb/sr (2-14°) in 1.51-1.55GeV/c2 U.L.(90%CL) of GQ 0.72 MeV (1/2+) 3.1 MeV (1/2-) PRL 109 (2012) PRL published Updated data with higher beam momentum exists. See Dr. Naruki’s talk. 2013/10/30 Hadron Experiment, K. Ozawa

44 Hadron Experiment, K. Ozawa
H dibaryon search (E42) The observation of several double-L hypernuclear events in nuclear emulsion suggests that the H-dibaryon is very closely bound or unbound relative to 2mL . Some experimental results show an enhancement just above 2mL mass (~ 2250 MeV/c2). J.K. Ahn et al., PLB 444 (1998) 267 C.J. Yoon et al., PRC 75 (2007) (R) Weakly-bound : H -> Lpp Virtual state : LL threshold effect Precise measurements of LL and Lpp productions in 12C(K-, K+) reactions are proposed. Forward K spectrometer and a time projection chamber around the target is used. Experimental setups Expected spectrum for a virtual state 2013/10/30 Hadron Experiment, K. Ozawa

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

46 Diquarks Baryons as well as Mesons seem to be well described by a Rotating String Configuration with a universal string tension. Baryons Mesons L M2 (GeV2) M2∝1.1L The data are well fit on Regge trajectories with a universal string tension in both baryons and mesons. The configuration assumed in the model seems work well.

47 Emergent Diquarks “diquark” in low-lying modes qq q
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 A diquark-q picture of baryons seems valid in low-lying modes mq/mqqの効果が見えるときたいされる。 Udsのせかいだと、すべてのqqpairの効果が働いて、見にくくなる。 で、チャームバリオン。

48 Hadron Experiment, K. Ozawa
Heavy quark baryon l: orbital motion r: di-quark correlation 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 l is lowered due to the collectivity of the di-quark motion. Spin correlations between light quarks give additional level separations. Level pattern tell us: Mass of di-quark Strength of di-quark correlation Spin dependent correlation between light quarks 2013/10/30 Hadron Experiment, K. Ozawa Measurements of all levels are important

49 Missing mass Spectroscopy
2.3 Tm Dipole K+ DC PID Use forward D mesons production No Bias measurements up to 3GeV/c2 of Charmed Baryon mass H2 TGT PID Beam p- High rate Trackers (Fiber, SSD) DC p- TOF p- LAMPS Large Acceptance, Multi-Particle K, p from D0 decays Soft p from D*- decays (Decay products from Yc*) High Resolution High Rate SFT/SSD op. >10M/spill at K1.8 2013/10/30 Hadron Experiment, K. Ozawa

50 Expected Spectrum in the (p,D*-) reaction
Lc 1/2+ Sc(2455) 1/2+ Sc(2520) 3/2+ Sc(2800) ?? Lc(2595) 1/2- Lc(2625) 3/2- Lc(2880) 5/2+ Lc(2940) ?? DN pLc (GeV/c2) D*N 2.3 2.4 2.7 2.9 2.6 pSc 2.8 Signal: 1 nb/Yc* :~1000 events BG: 1.8 mb (JAM) Lc Sc(2455) Sc(2520) Lc(2625) Lc(2765) Lc(2880) Lc + 0.8GeV Missing Mass (GeV/c2) pSc DN D*N Lc(2595) Sc(2800) Lc(2940)

51 Hadron Experiment, K. Ozawa
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. 2013/10/30 Hadron Experiment, K. Ozawa


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