PS REVIEW 080122 1

Overview of Particle Physics ExperimentsIn the-35-year History of KEK-PS

Yorikiyo NagashimaOsaka University

Jan. 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 PS1964: Preliminary approval1966: 12GeV 40 GeV

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

Big debate in the academic community1971: Construction started.1977: Beam commissioning (812 GeV)

Dumping the cyclotron in Tokyo bay

Options discussd12GeV; high intensity40GeV; conventional80GeV; cascade

PS REVIEW 080122 3

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. (ν-oscillation, K-decays) +KEKB, SK

JPARC

PS REVIEW 080122 4

1m Bubble Chamber

E19: K.Miyake:π-p Charge Exchange Scattering

R.Kajikawa:E21: πp Elastic Scattering

BEAM

Polarized Tgt.

MAGNET

1st Experiments: πN ReactionsCounter Experiments; E19, E21Bubble Chamber; E6 , E12

TARGET

BEAM

PS REVIEW 080122 5

Summary Talk by Nambu

SM was firmly established in this conference.

ICHEP78, Tokyo, Japanese Debut in HEP club.

PS REVIEW 080122 6

Significance

Purpose

Problem

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

PS REVIEW 080122 7

Polarized Target

Horizontal TypeHe3-He4 Dilution Refrigerated

Special Features circa 1975that were hoped to makelate 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

PS REVIEW 080122 8

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

Debut in HEP Society at ICHEP’78 in Tokyo

Strategy 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 PSfrom Particle Physics Point of View (1a)

PS REVIEW 080122 9

PS　achievement in the 1st 10 years reviewed in 1990

PS REVIEW 080122 10

The following sample are picked up entirelywith my personal prejudice.My apology for not covering many worksthat achieved important conributions.

PS REVIEW 080122 11

Measurements of dp Reaction in 2.0-4.0 GeV/cTokyo U.H.SaiDPBCE80

Study of Exotic States in p-bar p Reaction at 3-5 GeV/cKEK/Tokyo U. NaraWomen's U. Hiroshima U.Niigata U.

Y.Yoshimurapbar-pE62

Studies of pp Interaction in the Range of 0.8-2.0 GeV/cTokyo U.S.YamamotoppBCE57

Studies of π-- Nucleus Interaction at 4 GeV/c in Bubble ChamberHiroshima U.S.KanekoπAE53

Direct Electrons in pp Interaction at 8 GeV/cTohoku u. Tohoku Gakuin U.Nara Women's U.

T.KitagakiDLBCE50

Study of π-p Three-Body Reaction with Emphasis on DiffractionTMU, TAITT. HiroseπDDE12

Study of Pion Nucleon Inelastic Scattering in the Intermediate Energy RegionKEK/Osaka City U.R. SugawaraRESE06

TitleOrganizationSpokesmanAliasExp.#

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

• 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 HuntingReactionｓHadron

PS REVIEW 080122 12

Models including Di-Baryon

Δ-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

σ(ppπ0)σ(pnπ+)

Spires2008

13

OtherDecaysResonance HuntingReactionHadron

Search for Heavy Neutrinos by Kμ2 DecayTokyo U.T.YamazakiKµIIE104

Polarization of μ+ in K+ → μ+ν DecayTokyo U.R.HayanoKµpE99

Measurements of Asymmetry in Σ+ → pγ DecayKyoto U.K.MiyakeΣE92

Detection of Monochromatic μ+, e+ Associated with Heavy Neutrinos in K+ → μ+v and e+ν DecayTokyo U.T.YamazakiKµE89

Dibaryon Resonance in πD ScatteringHiroshima U.Y.SumiπDE83

Asymmetry in K+d and π+d Elastic Scattering around 1.5 GeV/cUCLA/KEKG.IgoKDELE81

Measurement of P-parameter in pn Elastic ScatteringKEKK.OgawaPNE75

Baryonium in p-bar p Reaction below 1.0 GeV/cTokyo U.K.NakamuraPbarPRE74

Detection of Discrete γ and π0 from p-bar p SystemKEKS.KobayashiPbarPC

E68

Studies of 2π, 3π States in π-p Charge Exchange ReactionKEKT.TsuruπIE64

Measurements of Differential Cross Section and Polarization for π-p →π0 n in 1.8-3.0 GeV/cKyoto U.K.MiyakeCEXHE63

Study of Asymmetry in Λ→ peν, pμν Decay by Hyperon BeamTsukuba U.K.TakikawaΛE49

Direct Lepton Production by ProtonKEKS.MikamoDLCE45

Study of K+n↑→K+n, K0p and K-p↑→K0n ReactionKEKF.TakasakiKNE34

Study of Narrow Resonance in pbar-p Reaction below 1 GeV/cTokyo U.T.KamaeYNE33

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

Nagoya U.R.KajikawaπNE21

Measurements of Differential Cross Section and Polarization for π-p →π0 n in 1.8-3.0 GeV/cKyoto U.K.MiyakeCEXE19

Study of Rare Decay K+→ π+ννbar, π+axionKEKY.NagashimaKdecayE10

TitleOrganizationSpokesmanAliasExp.#

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

OthersDecaysResonance HuntingReactionｓHadron

2/3 Hadronic, very little interest in WeakDecays in the beginning

PS REVIEW 080122 14

C-type Magnet

Beam

Polarized Target

Beam

An Example of Experiments with Polarized Target

PS REVIEW 080122 15

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

E34 results

Looked for possible S=1exotic BaryonsAnd found none.

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

• 2 Complex Amplitudes in π(Κ)N Scattering• Need Cross sections, Polarized target Data and Polarization ofscattered particles.

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

PS REVIEW 080122 16

“ 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”

Experiments that targeted specific Resonances

Spires

Spires2008

PS REVIEW 080122 17

E10 Y.Nagashima:

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

An Example of Deacay Experiments

PS REVIEW 080122 18

KEK/PS:E10

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

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

Spires2008

PS REVIEW 080122 19

Another Example of Weak Decays during PSI period

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

PDG2006

E92 K.Miyake:

PS REVIEW 080122 20

Summary of PSIb: 1979-84Making 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: beam delivery not enough and approval criteriasomewhat 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 PSfrom Particle Physics Point of View (1b)

16-19

PS REVIEW 080122 21

Features in PSII Period: 1985-1998The 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 PSfrom Particle Physics Point of View (2)

PS REVIEW 080122 22

Precise Measurement of μ+ Longitudinal Polarization in the DecayK+ → μ+ν

KEKJ. ImazatoPµE195

setup as π I-I, II, IIISearch for the ηπ Resonance with I = 1, J PC = 1-+KEKT.TsuruηπE179

Ay Measurements for NN ReactionTexas A&ML.NorthcliffRINGE174

Experimental Study of Rare KL DecaysKyoto U.N.SasaoCPE162

setup as p nAnalyzing Power in the p↑d →pd Reaction at 3.5 GeVNagoya U.N.HorikawapDELE159

Search for Rare Decay KL → μeKEKT.InagakiKLE137

Search for Long Lived Hadrons with Charge 2Kyoto U.N.SasaoZ2E136

setup as π I-I, IIMeson Spectroscopy in π-p Charge Exchange ReactionKEKT.TsuruπI-IIIE135

Confirmation of Mesonic Resonance (1935) in p-bar p → K+K- ReactionTokyo U.T.FujiiPbar-PRE131

Studies of dd Interaction in the Range of 2-4 GeV/cTokyo U.S.YamamotoDDE125

setup as π I-IStudy of a Few Pion States in π-p Charge Exchange ReactionKEKT.InagakiπI-IIE121

Spin Correlation Parameter Ann in pn Elastic ScatteringNagoya U.N.HorikawapnE119

commentTitleOrganizationSpokesmanAliasExp.#

List of Counter Experiments in PSII (1985-98)

OthersDecaysResonance HuntingReactionｓHadron

PS REVIEW 080122 23

An Example of series of Experiment :

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

“Exotic Resonance Search in πp channel”

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

PS REVIEW 080122 24

Contributions in the glueball-hybrid-4q sector.

•Confirmation of IG(JPC)=0+0-+ Resonances in ηππ system known today as η(1295) and η(1405) PRL57(1986)1296, PLB267(1991)293•Indication of 1-1-+ Resonance in ηπ- system known today as π1(1400) PLB267(1991)293

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

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

• π1(1400), having I=1 cannot be a glueball, but a possible candidate for a hybrid or 4q state.

f1(1285)

Spires2008

PS REVIEW 080122 25

“Search for a Heavy Neutrino in K+µ+ν, µe+νν”

Another Systematic Approach: Kµ2 Decay Experiment

PSI Era

E89

E89, E104: T.Yamazaki:

Spires2008

PS REVIEW 080122 26

E195 setup

E99 R.Hayano, E195 J.Imazato:

“Upper Limit on the Mass of WR As a function of mixing angle”

E195

TRIUMF

Kµ2 Decay Experiment : PS II Era

PDG2006

Search for Right-Handed Currents in the Decay Chain K+µ+ν, µ+e+νν

PS REVIEW 080122 27

Search for Rare Decays KLµe 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:

PS REVIEW 080122 28

PSII Period: 1985-1998The 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

PS REVIEW 080122 29

A Track of PSfrom 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 JPARCK2KT2K (E11), E391aE14, E246 E06

setup as E 246Measurement of direct photon emission in K+ → π+π0γIPNST.BakerE470

Measurement of the KL → π0νν-bar DecayKEKT.InagakiE391a

Long Baseline Neutrino Oscillation ExperimentKyoto U.K.NishikawaK2KE362

Search for T violation in the K+ → π0µ+ν decayKEKJ. ImazatoE246

TitleOrganizationSpokesmanAliasExp. #

List of Counter Experiments in PSIII (1999-2005)

OthersDecays

PS REVIEW 080122 30

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

PS REVIEW 080122 31

PDG2006

E246

PS REVIEW 080122 32

ν1

ν2

γ1

γ2KL

E391a Detector

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

KEK-PS E391a JPARC

E391a

PS REVIEW 080122 33ADOPTED FROM T.SUMIDA; 070316

PS REVIEW 080122 34

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

PS REVIEW 080122 35

KEK

SuperKAMIOKANDE

250km

ニュートリノビーム

PS REVIEW 080122 36

PS REVIEW 080122 37

T2K REACH

K2K T2K T2KK?

The Success of K2Kenabled us to draw a definite future plan.

Neutrino Physics

K2K

PS REVIEW 080122 38

~1GeV ν 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 onein Korea

PS REVIEW 080122 39

Summary IA Track of PS from Particle Physics Point of View

Pre PS : 1952-1976:Long Hard Labor for HEP Accelerator Re-construction

1st Period: 1977-84Training Period: Debut in HEP Society at ICHEP’78 in TokyoPre-construction emphasis: Resonance Hunting and Precision HadronDynamics 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+π+νν, π+axion, µν

2nd Period: 1985-1998The Main Force TRISTAN+Overseas CollaborationsPS : Groping the way of Uniqueness and Originality Systematic Approach and Precision Tests: Κ0πµ, Κ+µ+ν Nuclear Experiments

3rd Period: 1999-2005Frontier and World Leading Experiments (in parallel with BELLE and SK) T in K0πµν, K2K (LBL ν oscillation), CP in K0π0ννInternational Collaborations

PS REVIEW 080122 40

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 apartner in the world HEP society, and to educate youngpeople 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 someforefront particle physics results, including the renownedlong baseline neutrino oscillation experiment.Waves of Internationalization have reached KEK/PS.The PS Experiments owe their Success to the stableoperation of the Accelerator throughout its Life.The success of late time PS activities paved a road toJPARC and other future projects.

32-35

PS REVIEW 080122 41

PS REVIEW 080122 42

PhDTheses

Published papers

PhD取得者　(PS初期実験)泡箱実験E06　KEK/市大　福井E12　都立大/農工大　福永E53　広大　中村E57　東大　小磯、佐井

カウンター実験E19　京大　鈴木(洋)、箕輪、安達E21　名大/広大/KEK　下村、松井、寺田、門田、尼子E34/75　KEK/東大　金、中島、京大 作田E33/74　東大　福間、高田、岩崎E10　KEK　新川、菊谷E45　KEK/市大/京大　内藤E65　東大 小林