1. POFPA 17/3/06 A. Ceccucci
K & B: Theory vs. Experiments
LFV: further motivation to study rare kaon decays
Report from my visit to Japan

2. K & B: Theory vs Experiment
SM Observable
Theoretical error
Experimental error
B(K0Lp0 n n)
~3% ??
B(K+p+ n n)
~6%
~75%
AFB(B  Xsl+l-)
~8%
B(B  Xsg)
~10%
~9%
B(B  Xsl+l-)
~13%
~20%
AFB(B  K(*)l+l-)
~15%
~30%
B(B  (K(*),r,w)g)
~25%
~40%
B(Bs  m+m-)
< 2 x 10-7
B(B  K*l+l-)
~35%
Adapted from U. Flavour in the LHC era, 6-8 Feb 06, CERN

3. hep-ph/

4. : Physics Motivation [1] Helicity suppressed decay [2] Decay Form of
: left-handed (in SM)
: spin 0
p0 copiously collected from K+  p+p0
[1] Helicity suppressed decay
(A) Neutrino mass : implies
(B) Neutrino type : Majorana neutrino  x2 larger branching ratio.
[2] Decay Form of
(B) Decay into different neutrino flavors :
(A) Sensitive to any hypothetical weakly-interacting neutrals.
[3] Cosmological Interests
Neutron star cooling model through pion pole mechanism :

5. Branching Ratio New upper limit (E949) :
2/3 sample Saturation at 3.5x106
1/3 sample
Conservative upper limit
# signal < 113 (90%CL) subtracting the non-Kp2 bkgnds;
New upper limit (E949) :
A factor of 3 improvement from the previous best result.

6. Ceccucci visit to Japan CERN, March 16, 2006
Workshop poster
Summary of
Ceccucci visit to Japan
CERN, March 16, 2006

7. “Mass Origin and Supersymmetry Physics” Grant in Aid for Scientific Research in Priority Areas Research period: April 2001 ～ March 2006
Purpose of this Research Program
Pursue the answers to the following questions:
Why does the matter have its mass ?
What kind of physics law gives the mass of the matter ?
〇 Search for the Higgs particle, the mass origin.
　　 Proton Antiproton collision experiment at highest energy
（ CDF experiment）
〇 Search for deviation from the Standard Model prediction,
New Physics such as SUSY.
　 Precise measurement with factory accelerators
　　　 （ top, B, tau, K factories） 〇 Research and development for next-generation accelerator experiments.　
　　　 （ LHC, ILC，J-PARC，SuperB)
〇 Theoretical studies closely related to these experimental studies.

10. E391a Collaboration
High Energy Accelerator Research Organization, KEK, Japan
Joint Institute for Nuclear Research (Dubna), Russia
Department of Physics, Kyoto University, Japan
National Defense Academy of Japan, Japan
Department of Physics, National Taiwan University, Taiwan
Department of Physics, Osaka University, Japan
Department of Physics, Pusan National University, Korea
Research Center for Nuclear Physics, Osaka University, Japan
Faculty of Science and Engineering, Saga University, Japan
Department of Physics, University of Chicago, USA
Department of Physics, Yamagata University, Japan

11. E391a method to detect KL  ponn
(along the beam axis)

12. E391a result at the KAON2005

13. Direct comparison Run-I and Run-II
5evts
1evts
0evts
4evts
With the same data processing and cuts

14. Expected sensitivity Single Event Sensitivity G-N Limit
KTeV Limit
(Current Exp. Limit)
Single Event Sensitivity
G-N Limit
1-day week Run-I Run-II Run-III

16. Summary Our Japanese Kaon Colleagues are using a step-by-step approach
E391a hopes to reach the Grossman-Nir bound with the accumulated data (still two orders of magnitude from SM)
E391a made some progress w.r.t. KAON2005
Neutron background must be handled
In the longer term:
Aim to measure ~100 SM K0L  p0 nn at J-PARC Phase II by 2015 if Phase I is successful
Proposal for J-PARC Phase I due by end of April 2006
No firm plans for K+
E949 detector may be used for penta-quark searches)
They are looking for collaborators (as P-326 do!)