The above results are obtained after hot-block suppression.
In order to do that, events with clusters that consist of
just one LGD block are eliminated from the sample.
Although we can see clear and
production there are several problems that have to be resolved.
First, the
mass is close to its right value (782 MeV)
for the low energy threshold, but it increases with increasing energy
threshold in the LGD. For the last energy cut, it is higher than expected
by
40 MeV.
Second, the
mass also increases with energy,
but contrary to the
, the value from the fit is lower than expected (1020 MeV).
The difference varies with energy from 90 to 50 Mev.
Finally, the ratio of
is less then expected: about 20
times as many
's as
's, independent of the energy cut.
The production cross section is in favour of
by a factor of
4.
The ratio of branching ratios
Br(
-
)/Br(
-
)
is
6.5 and an additional factor of 2.5 comes from the ratio of
/
decays to 2
.
Putting it all together, we expect
60 times more
than
, but we see only 20.
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3.5 | 0.791 | 0.060 | 8.98 ![]() |
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4.0 | 0.798 | 0.065 | 8.30 ![]() |
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4.5 | 0.805 | 0.064 | 4.83 ![]() |
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5.0 | 0.819 | 0.061 | 1.95 ![]() |