Status Report on
f  hg  p+p- 7g
Status Report
• The branching ratio measurement is ready
– R=BR(fhg)/BR(fhg);
– Filfo-EVCL efficiency measured on data;
– Systematics related to TRK-VTX on the
control sample f p+ p- p0 ;
– MC’04 studied;
– Discussion with referee  work in progress.
• Mixing angle evaluation
2
BR(fhg) measurement
BR(fhg) with p+p-7g :
• crg h hp+p- and h p0p0p0
• ntr h hp0p0 and h p+p-p0
BR(fhg) measurement and P evaluation
on 2001-2002 data, run 17874-26965;
Lint =427 pb-1
We look at the fhg with hp0p0p0
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EVCL-Filfo
Using 40pb-1 selected with a minimum bias
procedure and without EVCL and Filfo (see
kloe memo 365) we measure eEVCL-Filfo on data
and we use the results directly in the ratio R
e
hg
e
h g
FE
FE
 97.88%

BR

e e
crg
e crg + BRntr e ntr
BR
crg
MC
 e FE
+ BRntr

  96.72%
Nev
 300
•With ktagVeto(EVCL)
•With Ep++Ep-<500MeV
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TRK-VTX efficiency
We use fp+p-p0 as control sample for track-vertex
efficiency
run 21524-22745; Lint =9 pb-1
mc
mc
fp+p-p0
Pp MeV
fhg
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Pp MeV
TRK-VTX efficiency
We ask for:
• one track with 200 < Ptrk < 400 MeV, associated
to a cluster in the calorimeter;
• two prompt neutral clusters over 25º with
87 < Mgg < 183 MeV
TRK and VTX efficiency as function of
missing momentum
p

miss
pf - p
trk
pg - pg
1
2
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TRK efficiency
MC
DATA
• we look for a track
in a cone (20º)
around the
direction of
missing momentum
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TRK efficiency
A0=0.6±1.3%
(50:250)MeV
emc-erd/ emc 1.3%
A0=0.5±0.8%
(10:500)MeV
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VTX efficiency
MC
DATA
• We look for a
vertex connected
between the tracks
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VTX efficiency
10
VTX efficiency
A0=-1.3±1.4%
(50:250)MeV
emc-erd/ emc 1.4%
A0=-0.7±0.9%
(10:500)MeV
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Accidentals h
Signal: we compare MC efficiency with and
without validate cluters procedure, using
dtr_stream_code = ‘mrc’ AND mc_card_code
= ‘rad04’ and we found difference at the
level of 0.5% on the selection efficiency
Validate cluters: we use efficiency table from S.
Miscetti to solve the clusters background problem
in rad04 (by Paolo Massarotti)
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Background h
Possible background can be produced by
f  Ks Kl:
1. Ks p+ p- ; Kl p0 p0 p0
2. Ks p0p0 ; Kl p+ p- p0
3. Ks p+ p- g; Kl p0 p0 p0
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Background subtraction h
We observed Nob.ev.= (3750 ± 61) no background subtracted.
From MC study the expected background is
Nbg = Nbg1 +Nbg2+Nbg3 = 59+155+131
it’s at level of 9.2% on Nob.ev.; from MC’04 with right
machine background simulation, but low statistic, the
expected Nbg is at level of 8.5% on Nob.ev..
We use the discrepancy as systematics, it’s at level of 7.5%
on Nbg, so Nbg=34528
Nh’g = Nob.ev. - Nbg= 3405 ± 61stat ± 28syst
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fhg with hp0p0p0
We observed Nev.=(1665000±1300) f
with 7g, with a selection efficiency of
(28.170.04%)
eMC*eFE=28.78%*97.88%
From MC study we estimated a background at
level of 1•10-7 Nf @90% C.L.
(F.Perfetto Degree Thesis)
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We measure the ratio R
e FE RD
e MC  BR h  3p 
BR f  h g  N
R 
 hg
 hg  K 
BR f  hg  N BRcrg e crgMC + BRntr e ntrMC e FE RD
h g
where
hg
0

hg

BRcrg  BR h   p +p -h   BR h  p 0p 0p 0 
BRnrt  BR h   p 0p 0h   BR h  p +p -p 0 
R  (4.76  0.08  0.20)  10
-3
1%  1.3%  1.4%  0.8%  0.4%  1.5%  3%
Filfo-EVCL
TRK
VTX
bg
eh/eh'
c2/Ndf
BR" 16
BR(fhg) measurement
BR f  h g   R  BR f  hg 
BR f  hg PDG  1.295  0.025%
BR f  h g   6.16  0.10 stat  0.28sys 10
17
-5
Conclusions (I)
• We look at the full 2001-2002 KLOE statistic;
• EVCL-Filfo systematics using 10% of the
analysed data;
• MC’04 systematics on background subtraction;
• VTX –TRK efficiency with f p+p-p0
• BR(fhg) measurement completed, using fhg
with h p0 p0 p0: we measured the ratio
R=BR(fhg)/ BR(fhg)
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Conclusions (II)
We found
• BR(fhg) =(6.16±0.10stat±0.28sys)•10-5
to be compared with BR(fhg) = (6.10±0.61±0.43)•10-5
measured with p+p-3g (our Phys. Lett. B541 (2002))
• Mixing angle P  40°
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