Post on 11-Jan-2016
description
Decays Working Group Activities
1. systematics studies concerning the had
measurement
2. first results in Dalitz plot parameters
3. background and a new upper
limit
GENERAL MEETING
Federico Nguyen - October 10th 2002
GENERAL MEETING
Trackmass, Acceptance and
Filfo studies for the had
measurement
Trackmass, Acceptance and
Filfo studies for the had
measurement
Federico Nguyen
October 10th 2002 General Meeting
Mtr
ack (M
eV)
Trackmass Systematics (I)
M2 (GeV2)
m
0)(M||M||M 2γ
221
22trk
22
2trk
21φ qpppp
some sources of background can be seen in the Mtrk - distribution:
- :at high values of Mtrk
which is M2 dependent
- :at Mtrk 104 MeV
MeV220M.AND1.MeV105
MeV250M
GeV0.85
M.AND.MeV120M trk
2
trk
2
2
2ππ
trk
Federico Nguyen
October 10th 2002 General Meeting
Trackmass Systematics (II)
2 MC samples differingonly for Fvalues
β1
βBWα1
)αBW(1BW
Fρ'
ωρ
π
0.145β
101.85α
MeV150.7Γ
MeV768.5M
FZK
3
ρ
ρ
0.1473β
101.48α
MeV143.7Γ
MeV772.6M
LNF
3
ρ
ρ
FZK(M) LNF(M)
at the level 2% Switched OFF PPGTAG and PPFILTSwitched OFF PPGTAG and PPFILT
Federico Nguyen
October 10th 2002 General Meeting
Geometrical Cuts Systematics (I)
our acceptance selection:
400 < +,-<1400 and
(pt>160 MeV or |pz| >90 MeV)
00 < < 150 or 1650 < < 1800
E > 10 MeV
we studied acceptance
cuts dependence on F
parameters by generating
stand alone MC samples
(NTOT=106 events) with
different M orvalues
covering the
whole phase space
there is no significant dependence on F
parameters in acceptance studies
there is no significant dependence on F
parameters in acceptance studies
Federico Nguyen
October 10th 2002 General Meeting
Geometrical Cuts Systematics (II)
[(772.6)-(770)]/(772.6)
[(772.6)-(780)]/(772.6)
geomgeom
MM2 2 (GeV(GeV22))
MM2 2 (GeV(GeV22))
MM2 2 (GeV(GeV22))
dependence on M - we fixed the other parameters
Federico Nguyen
October 10th 2002 General Meeting
Geometrical Cuts Systematics (III)
[(143.7)-(140)]/(143.7)
[(143.7)-(150)]/(143.7)
Q2
Q2
geomgeom
MM2 2 (GeV(GeV22))
MM2 2 (GeV(GeV22))
MM2 2 (GeV(GeV22))
dependence on - we fixed the other parameters
Federico Nguyen
October 10th 2002 General Meeting
Filfo Systematics (I)
o Filfo efficiency is evaluated from
DATA by reprocessing RAW
without using Filfo as a filter
o to overcome the long
reconstruction time, a prefilter,
based on CALORIMETER and
PATTERN RECOGNITION, is used,
then TRACK, VERTEX modules are
called...
FILFO/par=5: FILFO/par=5: ~ 2000 refiltered files~ 2000 refiltered files 6 pb-1 6 pb-1from different periods of 2001 DATA takingfrom different periods of 2001 DATA taking
Overall efficiency:Overall efficiency:DATADATA FILFO, SMAFILFO, SMA= (94.82±0.07) %= (94.82±0.07) %
errors errors ~~ 0.5-1% per bin0.5-1% per bin
MM2 2 (GeV(GeV22))
MM2 2 (GeV(GeV22))
Federico Nguyen
October 10th 2002 General Meeting
Filfo Systematics (II)
MB[205 events]
COS[659 events]
BHABHA[3955events]
4734 events
MM2 2 (GeV(GeV22))
signal events vetoed by FILFO/par=5
by the following:• Bhabha-filter (83.5%)• Cosmic-filter (13.9%)• Machine Background
filter (4.3%)
Federico Nguyen
October 10th 2002 General Meeting
Filfo Systematics (III)
o we wanted to know the
difference in applying Filfo at the
beginning or at the end of our
analysis chain
o resulting systematic correction:
= (-0.71 ± 0.07)%
FILFO/par=5: FILFO/par=5: 2 2 10 105 5 stand alone MC eventsstand alone MC events
Overall efficiency (Filfo at the end):Overall efficiency (Filfo at the end):MCMC FILFO, SMAFILFO, SMA= (97.37±0.07) %= (97.37±0.07) %
Overall efficiency (Filfo at first):Overall efficiency (Filfo at first):MCMC FILFO, SMAFILFO, SMA= (96.66±0.07) %= (96.66±0.07) %
MM2 2 (GeV(GeV22))
MM2 2 (GeV(GeV22))
systematic Filfo checks havebeen performed
we plan to study Filfo changesin different periods
of DATA taking
systematic Filfo checks havebeen performed
we plan to study Filfo changesin different periods
of DATA taking
GENERAL MEETING
resolutio
n, fit procedure and results
resolutio
n, fit procedure and results
Federico Nguyen
October 10th 2002 General Meeting
Dalitz Plot Parameters: Definition
1Q
T3Y
Q
TT3X
0
-
1;0.895Y
1;1X
Ti kinetic energy of the i
Q m - 2m - m
usual decay rate in termsof slope parameters:
() |M(X,Y)|2
|M(X,Y)|2 1 + aY + bY2 + cX2
Federico Nguyen
October 10th 2002 General Meeting
Dalitz Plot Parameters: Resolution (I)
corecore = 0.042 = 0.042corecore = 0.034 = 0.034
Y resolution has been obtained by using 1.3105 MC events
it can be estimated either from or from from0
0πππηπ0 mEEmT
0
0
πγγπ0 mET
Federico Nguyen
October 10th 2002 General Meeting
Dalitz Plot Parameters: Resolution (II)
corecore = 0.028 = 0.028
Federico Nguyen
October 10th 2002 General Meeting
Fit Procedure and Results (I)
as a 1st approximation b c 0, , that
has
to be fitted on:
aY1|(Y)M| 2 the
PS(Y)X
2dX
Y)ε(X,
Y)N(X,(Y)M /obs
where:
N(X,Y) = # of events in the Dalitz plot
(X,Y) = efficiency (from an independent MC sample)
PS(Y) = phase space as a function of Y bins
Federico Nguyen
October 10th 2002 General Meeting
Fit Procedure and Results (II)
dN/dY dN/dY ~ 1 ~ 1 + aY+ aY
YY
16 pb-1 from 2000 DATAhave been studied (the same selection for the mixing angle analysis, Kloe Memo 266)
Federico Nguyen
October 10th 2002 General Meeting
Fit Procedure and Results (III)
dN/dY dN/dY ~ 1 ~ 1 + aY + bY+ aY + bY22
YY
resolution studies have been optimized,1st glance at DATA shows sensitivity to the quadraticslope parameter
resolution studies have been optimized,1st glance at DATA shows sensitivity to the quadraticslope parameter
GENERAL MEETING
selection cuts, possible background and
preliminary limit
selection cuts, possible background and
preliminary limit
Federico Nguyen
October 10th 2002 General Meeting
Analysis Requirements
Pre-selection:4 prompt clustersAngle between two clusters > 15°
Etot(clusters) > 900 MeV; Ptot < 110 MeV
Final Selection:
• Pkin-fit() > 0.01
• |M - 140| > 30 MeV
• E vs. cos plane cut
• |M – 550| < 45 MeV
after kin. fitafter kin. fit
before kin. fitbefore kin. fit
kinematic fit has been
studied on MC
(Ntot=3104 events)
EE (MeV) (MeV) EE (MeV) (MeV)
Federico Nguyen
October 10th 2002 General Meeting
Background Problem
Data2001 (59.933 pb-1) Cut Type
tot (
Pre-cuts 1345779
Pre-selection 4499 (0.3%)
Final Selection 179 (4 %)
All. 179 (0.013%)
inconsistent with MC estimated
background 59 events
perhaps a missing background:
4 e+ e-
0 2
MMrecoilrecoil of of 1 1 (MeV)(MeV)
MMMeVMeV
1 non 0 least energetic
can be rejected by can be rejected by 00 cut, cut,still we must know the tailsstill we must know the tails
peak peak
Federico Nguyen
October 10th 2002 General Meeting
Preliminary Results on 2001 DATA
MM (MeV) (MeV) MM (MeV) (MeV)
PAW raw fPAW raw fit:it:a+bx+cxa+bx+cx22+N+Nsignalsignal*Gauss*Gauss
Nsignal = 9 26, corresponding to 616 events out of 142 pb-1
Nupper (90% C.L.) = Nsignal + 1.28*Nsignal = 42, TOT = 21%
BR() < Nupper/(L**BR()*TOT) = 3.5 10-5
Nsignal = 9 26, corresponding to 616 events out of 142 pb-1
Nupper (90% C.L.) = Nsignal + 1.28*Nsignal = 42, TOT = 21%
BR() < Nupper/(L**BR()*TOT) = 3.5 10-5
from MC:from MC:GaussGauss = 13 MeV = 13 MeV
Federico Nguyen
October 10th 2002 General Meeting
Summary and Outlook
had:NO significant Fparameters dependence both in acceptance and trackmass,filfo efficiency has been studied,we started evaluating trackmass efficiency from DATA.
:resolution and fit procedure have been checked,work ahead: genuine 2D fit, 2001-2002 DATA analysis.
: background has been studied, but a MC code is needed,reachable limit (~ 500 pb-1): BR() < 2 10-5 .