Overview of KEK-PS
Experiments

K. Nakamura
IPNS, KEK
June 7, 2004
KEK-PS Extrenal Review

KEK-PS Experiments:
From Proposal to Execution•Proposals are submitted to the director of IPNS.

•PS-PAC (Program Advisory Committee) investigates– Scientific merit– Technical feasibility– Size and experience of the experimental group– Demands on the experimental program and resources•

If a proposal is approved, the experiment is fully
supported by KEK. (In a few cases, however,experimenters directly apply for a grant-in-aid from MEXT
or JSPS.)•EPPC (Experimental Planning and Program Coordination)
Office of Physics Division III deals with– Scheduling– FundingBrief History of KEK-PS• 1971 April• 1976 March
completed

KEK established
Construction of the KEK-PS

Proton beam accelerated to 8 GeV• 1976 December
Proton beam accelerated to 12 GeV• 1977 May
Physics experiments started
fast extracted beam for bubble ch.
exp’tsinternal target for counter experiments• 1978 April
Slow extracted beams for counter
exp’ts• 1981 June
External Review• 1987 February
Polarized proton beam acceleratedandextracted• 1990 February
New experimental hall (North Hall)
completed• 1990 November
External Review• 1994 December
External Review

Brief History of KEK-PS,cont’ed• 1996 September Construction of a neutrino beam linestarted• 1998 December
Neutrino beam line completed• 1999 February 3 Fast extraction succeeded• 1999 February
Commissioning of the neutrino beamline• 1999 June 19
Detection of the first K2K neutrino
event inSuper-K• 2000 December
External Review• 2001 November 12 Super-Kamiokande accident, End ofK2K-I• 2002 December
Super-Kamiokande rebuilt, Start ofK2K-IITrend of KEK-PS Experiments•

1977 - 1984 (Before TRISTAN)– KEK-PS was the only high-energy machine in Japan.
– Particle and hadron physics experiments were dominant.

•1984 - 1998 (After start of TRISTAN and before K2K)
– Nuclear and hadron physics experiments were dominant.
– Particle physics experiments mainly focused on KL and K+decays.
– Nuclear physics experiments mainly focused onhypernuclear physics.
– Demands for test beams for detector R&D increased
considerably.

•1999 (After start of K2K) ∼– As a strategy to provide 1020 POT to K2K as early as
possible, PS-PAC authorized to allocate• 2/3 of available beam time for K2K (fast extracted beam)• 1/3 for other experiments (slow extracted beam)≒ Before TRISTAN≒ After TRISTAN
and before K2K

≒ Before TRISTAN≒ After TRISTAN
and after K2K

KEK-PS Experiments in 2000 2004•

Neutrino physics•

K Decay Experiments•

Hadron and Neutron Physics (Other than Hypernuclear Physics)••–E362 Long Baseline Neutrino Oscillation Experiment–––

E246 Search for T-Violating Muon Polarization in K+ → π0µ+ν Decay
E470 Branching Ratio Measurement of K+ → π+π0γ Direct Emission
E391a Study of the KL→π0νν Decay–

E325 Chiral Property of Dense Nuclear Matter Through Measurement of Meson Mass
Modification inMedium
E443 Neutron-Production Differential Cross Sections in the (p,xn) Reaction at Forward Angle–Hypernuclear Physics–

E373 Study of S=−2 Nuclei by Emulsion-Scintillating Fiber Hybrid Method
E419 High-Precision Gamma Spectroscopy of Λ7Li Hypernucleus )E438 Study of Σ-Nucleus Potential by the (π-, K+) ReactionE452 Study of the Spin-Dependent Interaction in Σ+P Scattering
E462 Exclusive Measurement of Nonmesonic Weak Decay of Λ5He Hypernucleus
E508 Coincidence Measurement of the Weak Decay of Λ12C
E471 Search for Strongly Bound Kaonic System
E509 Gamma-ray Spectroscopy of Hyperfragments with Stopped KE518 High-Precision Gamma Spectroscopy of Λ11B
E521 Production of Neutron-Rich Λ Hypernuclei by the (π-,K+) Double Charge-Exchange
Reaction
E522 Enhancement of the ΛΛ Near the Threshold in the 12C(K-,K+ΛΛ) Reactions–E546 Measurement of Electronic X Rays Correlated with Pionic X Rays––––––––––

Kaonic Hydrogen X-Ray Experiment

Accelerator Operation Mode for Each Fiscal Year
Shifts

600

Slow
Fast

500

Long PS shutdown to construct
the fast extraction
system

400

K2K-II started inDecember.

Super-K accident
on November 12700

300
200
1000
Slow
Fast

FY98
25642

FY99
163362

FY00242300

FY99−FY04(plan) total

FY01322222

FY02354
209

Slow
Fast

FY03
135
485

1406 shifts
2012 shifts[FY04]
190
434
Fiscal Year

Number of Experiments for Each Category

11Neutrino
3Kdecay
Hadron211StrangenessAtomicTotal Executed Shifts from FY1999 to FY2003 [%]132

Neutrino
40Kdecay
HadronStrangeness

1116Atomic

Shifts

Allocated Machine Time for Each Category of Experiments
900
800
700

AtomicStrangeness
HadronKdecay600

Neutrino

500
400
300
200
1000

FY98

FY99

FY00

FY01

FY02

FY03
Fiscal Year

KEK-PS Experiments in JFY2004 - JFY2005•

Neutrino physics•K Decay•Hadron and Nuclear Physics•Constraints– E362 Long Baseline Neutrino Oscillation Experiment: currently
scheduled until end of March 2005
– E391a Study of the KL→π0νν Decay: 200 shifts extension requested– E548 Study of Kaonic Nuclei by the (K-,p) Reactions: 30+3 shifts
approved– E549 Confirmation of Nuclear Kaonic State and Search for its Excited
State: conditionally approved (90 shifts requested)– E559 High-Resolution Spectroscopy of Penta-Quark Θ+ : conditionallyapproved (80 shifts requested)– No experiments can run simultaneously with K2K.
– Slow extracted protons cannot be shared between the East and NorthHalls– K5 and K6 (SKS) can be operated simultaneously.
– April - June: ~10 weeks, 180 shifts physics run– October - December: ~12 weeks, 215 shifts physics run– January - March: ~11 weeks, 195 shifts physics run

KEK-PS schedule (JFY2004)
October
２００４
November

DecemberJanuary
２００５
FebruaryMarchPS Schedule for JFY 2004
Cycle.................Term............................User
04-1 :: Apr. 1 - Apr. 28, 2004 ::(slow extraction)
04-2 :: May. 18 - June 30, 2004 ::(slowextraction)04-3 :: June 30 - Jul. 23, 2004::(Booster)
04-4-1 :: Sep. 30 - Oct. 25, 2004 ::(fastextraction)
04-4-2 :: Oct. 25 - Nov. 22, 2004 ::(fastextraction)
04-4-3 :: Nov. 22 - Dec. 22, 2004 ::(fastextraction)
04-5-1 :: Jan. 13 - Feb. 14, 2005 ::(fastextraction)
04-5-2 :: Feb. 14 - Mar. 7, 2005 ::(fast extraction)
04-5-3 :: Mar. 7 - Mar. 31, 2005 ::(fast extraction).

KEK-PS External Review 1990
• Critical comments:– Particle physics experiments at KEK-PS in the 80’s
were topical but “one-shot” type rather thansystematic and programmatic. Follow-up efforts
needed.
– Limited use of new detection technologies.
– Low international visibility.

• Recommendations– Maintain flexibility to pursue topical experiments.
– Develop a small number of well focused and selectedprojects. Pursue them with the necessary
implementation of detector systems taking fulladvantage of new technology.

KEK-PS External Review 1994
: respected or achieved at least partly: not respected or achieved•

Recommendations: Encourage the neutrino oscillation experiment to start in1998 and complete data taking with 1020 protons hopefullyin 1-2 year run.
 Higher priority for E246 (T-violation) ; lower priority forE162 (CP-violation)
 Among strangeness experiments at KEK-PS, the SKS workon hypernuclei likely to have the highest priority.
Experiments with d and α beams generally encouraged.
 Many groups move too quickly from one uncompleted
experiment to the next new experiment which requires
substantial equipment construction. KEK management andPAC must provide a guide to conduct thorough studies of“hints” explored in one experiment before that group moves
on to the next.
Encourage the formation of a strong user’s association.

KEK-PS External Review 2000
: achieved or will be achieved•

Recommendations: Give the first priority to the K2K experiment. The proposed
detector upgrade and beam time of 1 1020 pot (protonson target) should be approved.
 Give a reasonable amount of time (about 25%) to slow
extracted beam allowing timely completion of on-goingexperiments and additional beam time for programs
including hypernuclei experiments using SKS. Availability oftest beams is also an important factor.
 Give E391 a priority assuming it successfully passes thelaboratory review on the feasibility of the proposed
detector construction in a timely manner. Then thelaboratory should make an effort to deliver beam time of 50days to E391.

KEK-PS External Review 2004
• Evaluation of the achievements of KEK-PS
experiments in 2000 – 2004
• Evaluation of the achievements of the KEK-PS
operation and service for experiments.
• Evaluation of the plan to convert both theexperimental activities and resources at theKEK-PS to those at J-PARC.
• Recommendations on– how the current activities at the 12-GeV PS should becompleted– how these activities should be maintained andcontinued to experiments at the J-PARC 50 GeV PS.