PS REVIEW 080122 1

Overview of Particle Physics Experiments In the-35-year History of KEK-PS

Yorikiyo NagashimaOsaka UniversityJan. 22, 2008

PS REVIEW 080122 2

Historical Background of PS construction.

Pre-history of PS1937: 1st Cyclotron at RIKEN , Osaka U.1943: 60 inch Cyclotron (2nd to Berkeley)1941-45: World War II1945: Destruction of the cyclotron.

Reconstruction banned by the Occupation Army1952: Peace Treaty ; the end of Occupation1956: Electron Synchrotron started (0.75 1.3 GeV)

History of PS Construction1958: Discussion started1962: Proposal of PS 1964: Preliminary approval 1966: 12GeV 40 GeV

Big debate in HEP community.1970: 40GeV 8 GeV, ¼ budget , ¼ manpower

Big debate in the academic community 1971: Construction started.1977: Beam commissioning (812 GeV)

Dumping the cyclotron in Tokyo bay

Options discussed• 12GeV; high intensity• 40GeV; conventional• 80GeV; cascade

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Infancy 　　　　　 Youth 　　　　　 Maturity

Discovery of the Electro-weak Theory　　 The Standard Model Established

Progress of Particle Physics in Japan

PSI ：　 Training Period. 　　　　　　　　　　　　　　　 +International CollaborationsPSII ：　 Frontier for NP, Survival for Particle Physics +TRISTANPSIII ：　 A New Frontier and World Leading Expts. (-oscillation, K-decays) +KEKB, SK

JPARC

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1m Bubble Chamber

E19: K.Miyake: -p Charge Exchange Scattering

R.Kajikawa:E21: p Elastic Scattering

BEAM

Polarized Tgt.

MAGNET

1st Experiments: N ReactionsCounter Experiments; E19, E21 Bubble Chamber; E6 , E12

TARGET

BEAM

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Summary Talk by Y.Nambu

The Standard Model was firmly established in this conference.

ICHEP78, Tokyo, Japanese Debut in HEP club.

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Significance

Purpose

Problem

PS Review ’81 after 4 years of Operation By Nambu, Kitagaki, Yamaguchi

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Polarized Target

Horizontal TypeHe3-He4 Dilution Refrigerated

Special Features circa 1975that were hoped to make the late comer PS competitive.

K2

High Quality Low Energy Separated BeamsFor Precision Data and Decays

1978

K3

Pol. Tgt. aimed at performing Precision Hadron Dynamics

And also Bubble Chamber Later

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PS-Ia: 1977-78 Significance: Training and Obtaining Self-confidence

Debut in HEP Society at ICHEP’78 in TokyoStrategy to make PS competitive:

Pre-construction emphasis: • Resonance Hunting and Precision Hadron Dynamics 40’’ Bubble Chamber and Polarized Target Obsolete after SM was established during the construction

After Beam Commissioning : Emphasis on SM test Exotic Resonances, Weak Decays• High Quality Low Energy Separated Beam

10-12

Did the Strategy work ? See the Achievement in the first 10 years

in advance.

A Track of PS from Particle Physics Point of View (1a)

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PS 　 achievement in the 1st 10 years reviewed in 1990

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The following sample are picked up entirely with my personal prejudice. My apology for not covering many works that achieved important contributions.

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List of Bubble Chamber Expriments in PSI (1977-80)Exp. #

AliasSpokesman

Organization Title

E06 RESR. Sugawara

KEK/Osaka City U. Study of Pion Nucleon Inelastic Scattering in the Intermediate Energy Region

E12 DD T. Hirose TMU, TAIT Study of π-p Three-Body Reaction with Emphasis on Diffraction

E50 DLBC T.Kitagaki Tohoku u. Tohoku Gakuin U. Nara Women's U. Direct Electrons in pp Interaction at 8 GeV/c

E53 A S.Kaneko Hiroshima U. Studies of π-- Nucleus Interaction at 4 GeV/c in Bubble Chamber

E57 ppBC S.Yamamoto Tokyo U. Studies of pp Interaction in the Range of 0.8-2.0 GeV/c

E62 pbar-p Y.Yoshimura

KEK/Tokyo U. Nara Women's U. Hiroshima U. Niigata U.

Study of Exotic States in p-bar p Reaction at 3-5 GeV/c

E80 DPBC H.Sai Tokyo U. Measurements of dp Reaction in 2.0-4.0 GeV/c• Note: The Bubble Chamber was very productive during 1960’s. So it was one of special-feature projects in the construction stage.• However, most basic resonances that contributed to the discovery of the Quark Model were already found and the emphasis shifted to exotics by the time PS started operation.• The BC without external trigger was no match against counter experiments in the field of high statistics battle, and was shut down in 1982.• Nevertheless, there were some experiments that did well.

Experiments in the first Period PSI (1977-84):

OthersDecaysResonance HuntingReaction ｓHadron

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Models including Di-Baryon

-dominance Model

E57 　 S.S.Yamamoto:“An Experiment that provided a basic set of data and also excluded the existence of I=1 dibaryons(2240), (2320)”

An Example of Bubble Chamber Experiments

(pp0)(pn+)

Spires2008

13

Hadron Reaction Resonance Hunting Decays Other

List of Counter Experiments (PS-I ; 1977-84)Exp. #

AliasSpokesman

Organization

Title

E10 Kdecay Y.Nagashima KEK Study of Rare Decay K+→ π+ννbar, axion

E19 CEX K.Miyake Kyoto U. Measurements of Differential Cross Section and Polarization for π -p →π0 n in 1.8-3.0 GeV/c

E21 N R.Kajikawa Nagoya U.

Measurements of Differential Cross Section and Polarization for π -p Elastic Scattering at 2-4 GeV/c

E33 YN T.Kamae Tokyo U. Study of Narrow Resonance in pbar-p Reaction below 1 GeV/c

E34 KN F.Takasaki KEK Study of K+n↑→K+n, K0p and K-p↑→K0n Reaction

E45 DLC S.Mikamo KEK Direct Lepton Production by Proton

E49 K.Takikawa Tsukuba U.

Study of Asymmetry in Λ→ peν, pμν Decay by Hyperon Beam

E63 CEXH K.Miyake Kyoto U. Measurements of Differential Cross Section and Polarization for π -p →π0 n in 1.8-3.0 GeV/c

E64 I T.Tsuru KEK Studies of 2π, 3π States in π-p Charge Exchange Reaction

E68 PbarPC S.Kobayashi KEK Detection of Discrete γ and π0 from p-bar p System

E74 PbarPR K.Nakamura Tokyo U. Baryonium in p-bar p Reaction below 1.0 GeV/c

E75 PN K.Ogawa KEK Measurement of P-parameter in pn Elastic Scattering

E81 KDEL G.Igo UCLA/KEK

Asymmetry in K+d and π+d Elastic Scattering around 1.5 GeV/c

E83 D Y.Sumi Hiroshima U.

Dibaryon Resonance in πD Scattering

E89 K T.Yamazaki Tokyo U. Detection of Monochromatic μ+, e+ Associated with Heavy Neutrinos in K+ → μ+v and e+ν Decay

E92 K.Miyake Kyoto U. Measurements of Asymmetry in Σ+ → pγ Decay

E99 Kp R.Hayano Tokyo U. Polarization of μ+ in K+ → μ+ν Decay

E104

KII T.Yamazaki Tokyo U. Search for Heavy Neutrinos by Kμ2 DecayOthersDecaysResonance HuntingReaction ｓHadron

2/3 Hadronic, very little interest in Weak Decays in the beginning

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C-type Magnet

Beam

Polarized Target

Beam

A Flagship Experiment during the early PSI period.

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Phase Shift Analysis of the Reaction K+NKN below 1.6 GeV/c PLB112(1982)80

E34 results

A kind of perfect experiment, but this one also looked for possible S=1 exotic baryons And found none.

Note: Emphasis before construction was on the “Perfect Experiment”• To determine the complex scattering amplitudes precisely,

• 2 Complex Amplitudes in N Scattering • Need Cross sections, Polarized target Data and Polarization of scattered particles.

• To determine exact locations of the resonances, with hope to elucidate the underlying dynamics.• However, QCD was established ~1973.

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“ Disproof of S-resonance(1936) claimed by several groups”

E33 T.Kamae, 　 E74 K.Nakamura:

E68 M.Kobayashi

Dotted lines observed by B.Richter et al., PRLB126(1983)284

“Disproof of other barioniums”

Many experiments targeted specific Resonances

Spires

Spires2008

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E10 Y.Nagashima:

A Table–top experiment : An extinct species of HEP apparatus

An Example of Deacay Experiments

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KEK/PS:E10

BR(K):“World’s best limit for nearly 10 years.”

BR(K++axion): “An experiment that killed the original axion.”

Spires2008

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Another Example of Weak Decays during PSI period

Measurements of Asymmetry in Σ+ → pγ Decay“QCD Effect”

PDG2006

E92 K.Miyake:

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Summary of PSIb: 1979-84 Making efforts to catch up with the world level .Emphasis on intense K beams and Polarized target

Hunt for exotic resonances: •

Test of SM or looking for a clue BSM in weak decays: •

Caveat: As the only national HE machine, the demand for PS was big. Beam delivery was not enough and approval criteria was somewhat lenient to satisfy the need of usersImportant Events outside KEK/PS:

In 1972: Prof. Koshiba initiated U. Tokyo-DESY collaboration.In 1978: Prof. Koshiba began to construct Kamiokande.In 1979: Japan-US collaboration program started (all major universities).In 1981: TRISTAN was approved.

A Track of PS from Particle Physics Point of View (1b)

16-19

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Features in PSII Period: 1985-1998 The Main Force TRISTAN+Overseas CollaborationsPS : Frontier for Nuclear Physics ( Talk by Nakai)

: Survival War for Particle PhysicsStill behind BNL and CERN,

Groped the way of Uniqueness and OriginalityStrategy: Ample Machine Time for a small number of Groups Systematic Approach in series of experiments High Statistics and Precision Tests of and beyond SM

Managed to produce some world competitive Results

A Track of PS from Particle Physics Point of View (2)

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List of Counter Experiments in PSII (1985-98) 　

Exp. #

AliasSpokesman

Organization

Title comment

E119

pn N.Horikawa Nagoya U.

Spin Correlation Parameter Ann in pn Elastic Scattering 　

E121

I-II T.Inagaki KEK Study of a Few Pion States in π-p Charge Exchange Reaction setup as I-I

E125

DDS.Yamamoto Tokyo U. Studies of dd Interaction in the Range of 2-4 GeV/c 　

E131

Pbar-PR T.Fujii Tokyo U.Confirmation of Mesonic Resonance (1935) in p-bar p → K+K- Reaction 　

E135

I-III T.Tsuru KEK Meson Spectroscopy in π-p Charge Exchange Reaction setup as I-I, II

E136

Z2 N.Sasao Kyoto U. Search for Long Lived Hadrons with Charge 2 　

E137

KL T.Inagaki KEK Search for Rare Decay KL → μe 　

E159

pDEL N.Horikawa Nagoya U.

Analyzing Power in the p↑d →pd Reaction at 3.5 GeV setup as p n

E162

CP N.Sasao Kyoto U. Experimental Study of Rare KL Decays 　

E174

RING L.Northcliff Texas A&M

Ay Measurements for NN Reaction 　

E179

T.Tsuru KEK Search for the ηπ Resonance with I = 1, J PC = 1-+ setup as I-I, II, III

E195

P J. Imazato KEKPrecise Measurement of μ+ Longitudinal Polarization in the Decay K+ → μ+ν 　

OthersDecaysResonance HuntingReaction ｓHadron

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An Example of series of Experiment :

Studies of 2p, 3p States in -p Charge Exchange Reactions. Search for the ηπ Resonance with I=1, JPC=1-+

“Exotic Resonance Search in p channel”

PS I Era E64 (I-I) T.TsuruPS II Era E121 I-II, E135 I-III, E179 p: T.Tsuru and T.Inagaki

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Contributions in the glueball-hybrid-4q sector.

•Confirmation of IG(JPC)=0+0-+ Resonances in system known today as (1295) and (1405) PRL57(1986)1296, PLB267(1991)293

•Indication of 1-1-+ Resonance in - system known today as 1(1400) PLB267(1991)293

•Note:• (1295) is probably a radial excitation of .•Old (1460) in KK is now (1405).

•It does not fit in quark model levels and has a large gluon component. •An excellent candidate for the 0-+ glueball in the flux tube model.•However, lattice QCD *does not favor the interpretation.

• 1(1400), having I=1 cannot be a glueball, but a possible candidate for a hybrid or 4q state.

f1(1285)

Spires2008

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“Search for a Heavy Neutrino in K++e+”

Another Systematic Approach: K2 Decay Experiments

PSI Era

E89

E89, E104: T.Yamazaki:

Spires2008

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E195 setup

E99 R.Hayano, E195 J.Imazato:

“Lower Limit on the Mass of WR

As a function of mixing angle”

E195

TRIUMF

K2 Decay Experiments : PS II Era

PDG2006

Search for Right-Handed Currents in the Decay Chain K+++e+

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Search for Rare Decays KLe and KLee“Lepton Flavor Violation”

Other Competitive Decay Experiments

Observation of the decay mode KL → π+π-e+e-

“CP Violating Effect + Higher Order Effect QCD”

PDG2006

PDG2006

E162 N.Sasao:

E137 T.Inagaki:

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PSII Period: 1985-1998 The Main Force TRISTAN+Overseas CollaborationsPS : Frontier for Nuclear Physics

: Survival War for Particle PhysicsStill behind BNL and CERN,

Groped the way of Uniqueness and OriginalityStrategy: Ample Machine Time for a small number of Groups A series of Experiments for Systematic Research High Statistics and Precision Tests of and beyond SM

Managed to produce some world competitive Results

PSII Summary

24-27

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A Track of PS from Particle Physics Point of View (3)

3rd Period: 1999-2005International CollaborationFrontier and World Leading Experiments

(Parallel activities: BELLE and SK)Some Experiments will be continued at JPARC

K2KT2K (E11), E391aE14, E246 E06

List of Counter Experiments in PSIII (1999-2005) 　

Exp. #

AliasSpokesman

Organization

Title 　

E246

　 J. Imazato KEK Search for T violation in the K+ → π0µ+ν decay 　

E362

K2K K.Nishikawa Kyoto U. Long Baseline Neutrino Oscillation Experiment 　

E391a

　 T.Inagaki KEK Measurement of the KL → π0νν-bar Decay 　

E470

　 T.Baker IPNS Measurement of direct photon emission in K+ → π+π0γ setup as E 246

OthersDecays

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PS is a Front Runner in the Internationalization A Historical Event in the Japanese Culture.

Genuine International Collaborative Researches==================== ==============•E246 (Imazato)

•Japan-Russia(INR)-Canada-Korea-Taiwan•MOU between KEK-INR in 1992•The Majority Members are from Abroad

•K2K (Nishikawa)•K2K-I: Japan-US-Korea (1995)•K2K-II: Japan-US-Korea-Italy-France-Spain -Russia-Switzerland-Poland-Canada (2002)•The Majority Members are from abroad.

•E391a(Inagaki)•PAC advised to strengthen the group•Japan-US-JINR-Korea-Taiwan

•K.Nakamura: Jan. 14, 2006

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PDG2006

E246

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KL

E391a Detector

Experimental challenge; meager positive signal Use Pencil beamDetector with complete veto systemHigh PT selectionStep by step approach

KEK-PS E391a JPARC

E391a

PS REVIEW 080122 34ADOPTED FROM T.SUMIDA; 070316

PS REVIEW 080122 35

• E326 (K2K): World’s 1st Long Baseline Oscillation Experiment.• Confirmed the oscillation discovered by SuperKAMIOKANDE.

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KEK

SuperKAMIOKANDE

250km

ニュ

ート

リノ

ビー

ム

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T2K REACH

K2K T2K T2KK?

The Success of K2Kenabled us to draw a definite

future plan.Neutrino Physics

K2K

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~1GeV beam

Kamioka JPARK 1 MW 50 GeV PS

Ｔ２Ｋ

T2KK　　　　

Super-K: 50 kton

Water Cherenkov

Hyper-K: 1 Mton

4 MW

K2K

A Future PlanK2KT2KT2KKBeam: 1MW4MWDetector: Super-KHyper-K (50 kton 1 Mton)Split it into 2 and place one in Korea

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Summary IA Track of PS from Particle Physics Point of

ViewPre PS : 1952-1976:

Long Hard Labor for HEP Accelerator Re-construction1st Period: 1977-84

Training Period: Debut in HEP Society at ICHEP’78 in TokyoPre-construction emphasis: Resonance Hunting and Precision Hadron Dynamics a 40’’ Bubble Chamber and a Polarized Target

Out-of-date after SM was established during the constructionAfter Beam Commissioning : Emphasis on SM test Exotic Resonances, Weak Decays Pbar pbarionium, K+axion

2nd Period: 1985-1998 The Main Force TRISTAN+Overseas CollaborationsPS : Groping the way of Uniqueness and Originality Systematic Approach and Precision Tests: 0 Nuclear Experiments

3rd Period: 1999-2005Frontier and World Leading Experiments (in parallel with BELLE and SK) T in K0, K2K (LBL oscillation), CP in K00 International Collaborations

PS REVIEW 080122 41

Summary IIKEK/PS, 15 years behind the world fronts like CERN/PS, BNL/AGS, could not expect a bright future. However, it fulfilled its primary purpose to become a partner in the world HEP society, and to educate young people who are working actively at today’s frontier.As a bonus it provided a new frontier for nuclear physics.As the second bonus, KEK/PS even produced some forefront particle physics results, including the renowned long baseline neutrino oscillation experiment.Waves of Internationalization have reached KEK/PS.The PS Experiments owe their Success to the stable operation of the Accelerator throughout its Life.The success of late time PS activities paved a road to JPARC and other future projects.

32-35

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