Physics at JParc Seonho Choi Seoul National University

Physics at JParc Seonho Choi Seoul National University

Main Goal u Construction of a beam line at JParc with Korean funding u Operation of the beam line under Korean flag u New physics program lead by Korean physicists u Cornerstone for a Korean lab similar to KEK u Revitalization of nuclear physics in Korea

History so far u April 2005 n n n Initiation at KPS meeting About 10 physicists (theory+experiment) Start of Hadron Physics group meeting u July – October n n n Visits by KEK physicists (S. Sawada, K. Tanaka, T. Nagae, J. Imazato) Presentation of the status of JParc and physics programs (Korean and Japanese) Discussion with Korean physicists

Brief Summary u Four projects of beam line for physics n n K 1. 8: Double strangeness (S=-2) K 1. 1: Single strangeness, KN system K 0. 8: Stopped K-beam High-p: Proton beam of 30 Ge. V/c n Exotic meson search with secondary meson beam n Meson-Nucleon Drell-Yann process to probe structure functions of mesons

K 1. 8 Beamline u The only beam line fully (almost) funded for the moment u Kaon beams upto 1. 8 Ge. V/c u Beam delivery scheduled on September 2008 u Mainly focused on the production and study of S=-2 and S=-1 system u Hyperon-proton scattering experiment

Recent Development u Hadron beam facility ranked “B” by Council for Science and Technology Policy (CSTP) of Japan u Call for help from international physics community u In worst case, possible delay of construction plan u Wait and see…

K 1. 1 Beamline u Next to K 1. 8 beam line, two possibilities of “next” one n n K 1. 1/K 0. 8 beam line High-p beam line u Physics with K 1. 1 beam line n n n S=-2, S=-1 hypernuclei Hyperon-proton scattering High resolution spectroscopy of S=-1 hypernuclei Neutron rich lambda hypernuclei Dense K-nucleus system Non-mesonic weak decay

K 1. 1 Beamline u My personal impression from K. Tanaka n n n Supported by large strangeness physics community of Japan (T. Nagae, K. Tanaka etc) All the available resources are being invested (other than those for K 1. 8 beam line) Probably easier option for a possible Korean participation

K 1. 1 Beamline u Pros n n Proven technology, almost guaranteed physics results (bread-n-butter experiment) Large manpower/know-how from Japanese side u Cons n n Most of the physics program already defined by Japanese group Not easy to start a completely new physics program (almost confined to strangeness physics)

K 0. 8 Beamline u Stopped K beam experiments n n n Rare decay K＋→ ＋ K 0 L→ Branching Ratio Kaon decay physics T-violation in K+ decays K＋→ 0 e＋ (Ke 3) branching ratio u Possibility of branch option from K 1. 1 beam line u Supported by J. Imazato

High-p Beamline u Use of 30 Ge. V/c (or 50 in the 2 nd phase) proton beam u Drell-Yann process with nuclear targets u Spin physics with polarized targets (proton or neutron) u Meson beams of various energy as a secondary beam n n Search for exotic baryons Meson-nucleus Drell-Yann process

High-p Beamline u Pros n n Relatively new territory – easy to promote Korean physics programs n Exotic baryon search n Meson-nucleus Drell-Yann n Spin physics with polarized neutron target Easy to expand to other new physics programs u Cons n n Relatively small hadron physics group in Japan – limited resources Untested physics programs – risk of no good results

Hadron Physics Workshop u An attempt to gather force of hadron physics group in Japan u Organized by S. Sawada u At KEK, Nov. 30 – Dec. 2 u Quite impressive list of invited talks n R. Jaffe, X. Ji, S. Brodsky etc

Our Options u Whole hadron physics program at JPARC maybe in jeopardy n n Possible Korean collaboration (money, resources etc) can put the Korean flag on the hadron facility. Price tag would be quite high u K 1. 1 beamline with 50% of construction budget n n Korean flag on one beamline May not be a leading role in physics programs

Our Options (cont. ) u High-p beamline n n n Comparable price tag as K 1. 1 beamline Possible leading role driving physics programs Limited help from Japanese side n Easy to find matching fund for our 50%? n Relatively small number of manpower n Korean manpower need to be invested for beamline design, construction etc.

What will happen immediately? u First call for proposal very near n n n At the latest, by the end of December Deadline by March 2006 4 proposals in preparation n Non-mesonic weak decay of L hypernuclei (K 1. 1) n Search for exotic baryons (High-p) n Study of meson structure functions using meson-nucleus Drell-Yann process (Highp) n Beam line proposal for secondary meson beams using High-p beam

Our resources u Faculty Members n n n J. -K. Ahn, H. -C. Bhang, Seonho Choi (ABC) HC Kim, SH Lee Anyone else? u Postdocs n n B. -H. Kang (new) Theorists?

Approach to the goal u 정책과제신청 n n 과학재단 (2006년 2월) 또는 학진 (2005년 11월 ) 빔라인 디자인, 가능한 실험프로그램 연구 u Then, what? n n n Not yet clearly defined path Approach via MOST? Need more manpower to convince the government

References u All the presentation files are available from the web n n http: //phya. snu. ac. kr/~choi/jparc Talks by n S. Sawada n K. Tanaka n T. Nagae n J. Imazato n ABC team