Physics at JParc Seonho Choi Seoul National University

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

History so far  April 2005 Initiation at KPS meeting About 10 physicists (theory+experiment) Start of Hadron Physics group meeting  July – October 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  Four projects of beam line for physics K1.8: Double strangeness (S=-2) K1.1: Single strangeness, KN system K0.8: Stopped K-beam High-p: Proton beam of 30 GeV/c Exotic meson search with secondary meson beam Meson-Nucleon Drell-Yann process to probe structure functions of mesons

K1.8 Beamline  The only beam line fully (almost) funded for the moment  Kaon beams upto 1.8 GeV/c  Beam delivery scheduled on September 2008  Mainly focused on the production and study of S=-2 and S=-1 system  Hyperon-proton scattering experiment

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

K1.1 Beamline  Next to K1.8 beam line, two possibilities of “next” one K1.1/K0.8 beam line High-p beam line  Physics with K1.1 beam line 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

K1.1 Beamline  My personal impression from K. Tanaka Supported by large strangeness physics community of Japan (T. Nagae, K. Tanaka etc) All the available resources are being invested (other than those for K1.8 beam line) Probably easier option for a possible Korean participation

K1.1 Beamline  Pros Proven technology, almost guaranteed physics results (bread-n-butter experiment) Large manpower/know-how from Japanese side  Cons Most of the physics program already defined by Japanese group Not easy to start a completely new physics program (almost confined to strangeness physics)

K0.8 Beamline  Stopped K beam experiments Rare decay K ＋ →  ＋  K 0 L →   Branching Ratio Kaon decay physics T-violation in K + decays K ＋ →  0 e ＋ (Ke3) branching ratio  Possibility of branch option from K1.1 beam line  Supported by J. Imazato

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

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

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

Our Options  Whole hadron physics program at JPARC maybe in jeopardy Possible Korean collaboration (money, resources etc) can put the Korean flag on the hadron facility. Price tag would be quite high  K1.1 beamline with 50% of construction budget Korean flag on one beamline May not be a leading role in physics programs

Our Options (cont.)  High-p beamline Comparable price tag as K1.1 beamline Possible leading role driving physics programs Limited help from Japanese side Easy to find matching fund for our 50%? Relatively small number of manpower Korean manpower need to be invested for beamline design, construction etc.

What will happen immediately?  First call for proposal very near At the latest, by the end of December Deadline by March proposals in preparation Non-mesonic weak decay of L hypernuclei (K1.1) Search for exotic baryons (High-p) Study of meson structure functions using meson-nucleus Drell-Yann process (High- p) Beam line proposal for secondary meson beams using High-p beam

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

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

References  All the presentation files are available from the web Talks by S. Sawada K. Tanaka T. Nagae J. Imazato ABC team