| DATE: |
2012-10-30 16:00 - 17:00 |
| PLACE: |
Building 4, room 345 |
| TITLE: |
Physics seminar / New Theta+ results from LEPS |
| CONTACT: |
Hiroyuki Nakayama |
| SPEAKER: |
Takashi Nakano (RCNP) |
| LANGUAGE: |
Japanese |
| ABSTRACT: |
New results of the penta-quark Theta+ study in the gamma d -> K+K- p n
reactions from LEPS will be presented.
First, in order to check the validity of the 5-sigma evidence which we
obtained by analyzing the data taken in 2002-2003, the same analysis
method (inclusive analysis where proton and neutron contributions were
not separated) was applied to the new data taken in 2006-2007. A
strong narrow peak in the Fermi-motion corrected K- missing mass was
not reproduced in the new data set.
To investigate the reason for the inconsistency, we applied an
exclusive analysis to the both data sets, where background processes
due to gamma p reactions were identified by energy loss information in
a trigger plastic counter which was placed just after the
liquid-deuterium target. A clear signal enhancement was seen in the
gamma n contributions of the both data sets, and a part of the
inconsistency was tuned out to be due to fluctuations in the proton
contribution of the previous data set. The signal enhancement was also
confirmed by a Monte-Carlo based exclusive analysis.
This talk will be given in Japanese. |
|
