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P erspectives o n charged K physics in KLOE 2 nd KLOE Physics Workshop , 10 th -12 th june 2002 Otranto (LE) M. Primavera for the Charged K Group : P. Branchini, V. Casavola, E. De Lucia, P. De Simone, - PowerPoint PPT Presentation
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M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
1
Perspectives on charged K physics in KLOE
2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
M. Primavera for the Charged K Group:
P. Branchini, V. Casavola, E. De Lucia, P. De Simone, E. Gorini, V. Kulikov, M. Martemianov, L. Passalacqua,
V. Patera, M. Primavera, G. Saracino, B. Sciascia, A. Ventura
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
2
Some Initial Remarks
Nothing concerning systematics
Just a “statistical exercise” based on preliminary results of all the analysis performed up to now extrapolating it to 500 pb-1 where KLOE can give significative impr.s in the present “K± scenario?”
No description about details of the analysis
Not all analysis at the same stage! Some numbers could change if new inputs
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
3
Ke3 and K3 decays, Vus
“Shopping list”
K masses and lifetimes
BR’s : K , K 0, K 3, Kl4
Conclusions
Cross Section (see Maxim’s talk)
Dalitz plots of K 0 0 , K + -
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
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K± Mass
World Data (in MeV)• 493.677 0.016 (fit) (PDG2001)
• 493.677 0.013 (average)
CPT measurement :
€
(MK + − M
K − )
World data (in MeV)• -0.032 0.090 (Ford,’72,1.5M)
Limited by the knowledge of m + - m - ( 70keV)
DataMC
=493.6 MeV/c2
=0.9 MeV/c2
=494.2 MeV/c2
=1.2 MeV/c2
Invariant mass of selected secondary particles triplets
K +-
Stat.:M ~ 2keV….but we are limited by DC calib.(p/p~10-4)
We can do better by using
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
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K± Life Time
World Data (in ns)• 12.385 0.024 (fit), 12.385 0.025 (average) (PDG)
• 12.451 0.030 (KOPTEV - 1995) K at rest
• 12.368 0.041 (KOPTEV - 1995) K at rest
• 12.380 0.016 (OTT - 1971) K at rest
• 12.272 0.036 (LOBKOWICZ - 1969) K in flight
• 12.443 0.038 (FITCH - 1965) K at rest
CPT measurement : averageKKτττ /)( −+ −
World data (%)
0.11 0.09 (Average) (PDG2001)
0.090 0.078 (best meas., ‘69)
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
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Normalized K time distribution
# Data / (t)
(ns)=12.400.08(stat)+(?)(sys)
500 pb-1 stat 0.015 ns
t (ns)
17.5 pb–1
(end 2000)
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
7
Branching ratios
Two body decays in K+K- stream
Main BR for K+K- decays
± 63.51%
±0 21.16%
±+− 5.59%
e±0 4.82%
±0 3.18%
±00 1.73%
K+
K
+
1
2
For 500 pb-1 we have (rec.) approx. 300*106 K+K
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
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Ratio o/
Zeller
Auerbach
Weissenberg
(ITEP) Usher(CERN)
KLOEPDG 2001
World data
0.3334 0.0028 (fit)
0.3316 0.0032 (Average) (PDG)
• 0.3329 0.0047 (USHER - 1992) (45k)
• 0.3355 0.0057 (WEISSENBERG - 1976)
• 0.305 0.018 (ZELLER - 1969)
• 0.3277 0.0065 (AERBACH - 1967)
0.3306 0.0012 (stat.)+(?)(sys.) (KLOE preliminary, 11.2pb-1)
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
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Ratio o/Exp. ratio (o/)
2 ndf = 0.532 for 16 points
R/R ≈ 1% (world average) 0.5‰ (500 pb-1 only stat!)
+ – , e±0± 0, 0 0
o
CMSmomentum spectrum for +K decay
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
10
Branching ratio o
Preliminary estimation for total statistics: 2.6 pb–1
(end 2000)
Exp. BR(o)
20.560.26(stat.)+(?)(sys)
World Data, PDG2001 (10 -2 )
• 21.17 0.14 (fit)
• 21.18 0.28 (best exp.,16k)
KLOE can measure absolute BR’s
BR/BR ≈ 1.3% (best meas.) 1‰ (500 pb-1 only stat!)
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
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Branching ratio
Exp. BR()
Preliminary estimation for total statistics: 2.6 pb–1
(end 2000)
World Data, PDG2001 (10 -2 )
• 63.51 0.18 (fit)
• 63.24 0.44 (best exp.,62k)
61.260.50(stat.)+(?)(sys)
BR/BR ≈ 0.7% (best meas.) 0.6‰ (500 pb-1 only stat!)
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
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K±±+– (τ±) and K±±00 (τ’±) decays
Extremely interesting decays from direct CP point of view,by measuring
€
Aτ (τ ')
= τ (τ ' )Γ (K +) −τ (τ ' )Γ (K−)
τ (τ ' )Γ (K +) +τ (τ ' )Γ (K−)
World Data, PDG2001• (0.7 1.2) 10 -3 (Aτ world average)
• (0 6 ) 10 -3 (At’ world average)
… unfortunately theory provides O(10-8) and KLOE could have sensitivities down to ~ 10-5 with statistics comparable to CP to 10-4 in neutral kaons! with 500 pb-1 and present ττ’) we cannot do better than PDG on Aτ’, Aτ
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
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K±±+– branching ratio
World Data ( 10 -2 )• 5.59 0.05 (fit), 5.52 0.10 (average) (PDG2001)
• 5.34 0.21 (PANDOULAS - 1970)
• 5.71 0.15 (DEMARCO - 1965)
• 6.0 0.4 (YOUNG - 1965)
• 5.54 0.12 (CALLAHAN - 1964, 2332 ev.)
• 5.1 0.2 (SHAKLEE - 1964)
• 5.7 0.3 (ROE - 1961)
€
K ± → π ±π +π − yield
≈ 300 pb−1
⇒ 150000 (500 pb−1)
⇒ ΔBR /BR ≈ 0.2%
(only stat.)
(2% best meas.)
€
K3π~ 0.5%
Without tagging!
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
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K±±+– decay
DataMC
DataMC
Momentum of selected secondary particles
Invariant mass of selected secondary particles triplets
85MeV/c
85MeV/c=493.6 MeV/c2
=0.9 MeV/c2
=494.2 MeV/c2
=1.2 MeV/c2
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
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World Data ( 10 -2 )• 1.73 0.04 (fit)
•1.77 0.07 (average) (PDG)
• 1.84 0.06 (CHIANG - 1972)
• 1.53 0.11 (PANDOULAS - 1970)
• 1.8 0.2 (SHAKLEE - 1964)
• 1.7 0.2 (ROE - 1961)
K±±00 branching ratio
Best measur. has 3.5% error,And it’s based on only 1307 events
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
16K±±00 measuring branching ratio and Dalitz plot parameters
K±±00 branching ratio Preliminary on 6.33 pb-1(December 2001)
€
K ± → π ±π 0π 0 yield ≈115 pb−1
⇒ ≈ 6 ×104 (500 pb−1)
⇒ ΔBR /BR ≈ 0.5% (only stat.)
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
17
Kl4 Decays
Good place to study hadronic physics and to test PT but low BR (~10 -5) :K+ +-e+e 3.910-5
K+ +-+ 1.410-5
K+ 00e+e 2.110-5
KL0 0ee 5.210-5
Form factors can be extracted from the decay rate as partial wave expansions containing the elastic scattering phase shifts (I
l)
K+e4 studied at CERN SPS (1977) by using 30000 rec. ev.
KLOE needs at least 10stat. to be significative, but
€
Ke4± yield ≈ 0.3 pb−1 ⇒ 150 (500 pb−1)
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
18Study on K±00e±e
Highest statistics in: (00e±e)/(0e±e) = (4.2±1.0)10–4 (BOLOTOV 86, 25 evts)
K±e±00 e studies World Data ( 10 -5 )• 2.1 0.4 (fit)
•2.54 0.89 (average) (Barmin 88,10 ev.)
1515 selected Ke4 events over 102600 MC generated
MC1.48% ~0.9 Ke4/pb–1 are expected on data
Only 2 Ke4 found in 6.33 pb–1 ~150 ev in 500pb–1
me
m
Data
m
me
MC rec
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
19
Vus from Kl3 decays
While theory provides the knowledge of form factors at q2=0:+ measured in Ke3 and K3, 0 only in K3 (suppressed in Ke3 by the
factor (me/MK)2 )
Assuming a linear expansion of the evolution of form factors f+
Kand f0K
( )
%2.0
sec100024.02386.1 8
=Δ
⋅±=
+
+
−+
τ
τ
τK
%8.0
sec1004.015.5 8
=Δ
⋅±= −
L
L
KL
τ
τ
τ
400 k
3 M
)0(+fVus
€
fx (0)
obtained by the measurement of
( ) ( ) Kll KBRK τ33 =Γ
€
fxKπ q2
( ) = fxKπ 0( ) ⋅ 1+
λ xKπ
mπ2
q2 ⎛
⎝ ⎜
⎞
⎠ ⎟
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
20
Experimental status of K+e3 and K+
3 decays
€
BRKe 3
+ = 4.85 ± 0.09( )%
ΔBR
BR=1.8%
€
+Ke 3
+
= 0.0278 ± 0.0019
Δλ
λ= 6.8%
3516, ‘72
( )%06.008.086.4 syststat ±±
syststat 002.00015.00293.0 ±±
€
0.0278 ± 0.0017stat ± 0.0015syst (KEK-E246)
(ISTRA+)
≥100 k, 2001 41 k, 2001-2002
€
+Kμ 3
+
= 0.031± 0.008 Δλ
λ= 25%
€
0Kμ 3
+
= 0.006 ± 0.007 Δλ
λ= 24%
syststat 002.0004.00321.0 ±±
( )%14.007.033.3 syststat ±± 2345,’72
syststat 002.0004.00209.0 ±±
statstat 004.0005.0022.0 ±±
(ISTRA+)
112 k
€
BRKμ 3
+ = 3.18 ± 0.08( )% ΔBR
BR= 2.5%
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
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€
Vus
Vus
= 0.59% ± 0.37% ± 0.86%
Vus with K+e3 decays
( )( )0
005.05.0
3
3
+
+
+
+
+
+ Δ±
Δ±⎟⎟⎠
⎞⎜⎜⎝
⎛ Δ±
Δ=
Δ
f
f
BR
BR
V
V
e
e
K
K
us
us
λ
λ
τ
τ
( ) 0084.09874.00 ±=+fContributions to the total error
0.22%(from the most recent measur.of
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
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K+
e3 yield in KLOE
€
NKe 3
± ≈ 2000 pb−1
⇒ 106 (500 pb−1)
⇒ ΔV /V ≈ 0.3%
20 pb-1
Preliminary
(stat. only)
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
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CP ASYMM. (g+- g-) / (g++ g-) Theory provides Ag,Ag
0 ~10-6 up to 10-4 (more effordable than Aτ(τ’))
K±±00 measuring branching ratio and Dalitz plot parameters
si = ( PK – Pi )2 i = 1,2,3
s0 = isi/3 = (mK2 + m
2 + 2m°2)/3 X = (s1 – s2)/m
2
Y = (s3 – s0)/m2
F(X,Y;g,h,k) = 1+gY+hY2+kX2
Dalitz plots parameters in τ(τ’) decays
Ag measured (-7±5) 10-3 with ~ 106 ev.(KLOE is out), Ag
0 never measured
1 year of data taking @NA48’ (~ 109 τ decays and ~ 108 τ’) Ag,Ag
0 ~ 10-4
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
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QUADRATIC COEFFICIENT k 0.0197±0.0045±0.0029 (BATUSOV 98)
ASYMMETRY (g+- g-) / (g++ g-)NEVER MEASURED
6.33 pb-1
~15500 K°°
(MC normalized)
KLOE 6.33 pb–
1 PDG
g 0.607±0.026 0.652±0.031
h 0.026±0.027 0.057±0.018
k0.0080±0.0037
0.0197±0.0054
VERY
PRELIMINARY
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
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Conclusions
We can improve life times, absolute BR’s and Vus knowledge, keeping well under control systematics
We cannot do much more on charged K masses
CP viol. in partial decay rates (Aτ(τ’) is out
We can measure Ag0 (but should be done before
NA48 !)
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
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%86.0%22.0%59.0 ±±=
us
us
VV
Vus with K+e3 decays (new)
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
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Present statistics
Experimental Data
Selection: 1099682 K± , 1075 K±3
MC stream1 K3p
Generated K±all 980k 800k
Generated K±±+– 54.8k 422k
Selection: 299880 K± , 352 K±3
3.16 pb-1 (July 2000, DBV4)
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
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Selected Kaons on MC
€
K3π≡
N(K ± → π ±π +π −)selected
N(K ± → π ±π +π −)generated
= (0.635 ± 0.012)%
)%05.050.30()(
)(±=
→→
≡ ±
±
generated
selected
allKNallKN
K
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
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±±+– Branching Ratio
=→
→= ±
−+±±
3
K
K
selectedallK
selectedKBR
(stat.) )%17.071.4( ±=
* Background contamination negligible (<0.3% from MC)
** 0.34% subtraction KPMFILT selecting nonK+K– events (MC)
(preliminary estimation)
*
**
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
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Statistics analized
3.16 pb-1 (July 2000, DBV4)Experimental Data
Selection: 1099682 K± , 869 K±±00
MC stream1 K3p0
Generated K±all 980k 560k
Generated K±±00 16.9k 285k
Selection: 299880 K± , 347 K±±00
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
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Selected Kaons on MC
€
K ≡N(K ± → all)selected
N(K ± → all)generated
= (30.50 ± 0.05)%
)%025.0826.1()(
)(00
00
3±=
→→
≡ ±±
±±
generated
selected
KNKN
K
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
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±±00 Branching Ratio
=→
→= ±
±±
3 )(
)( 00
K
K
data
data
allKN
KNBR
(stat.) )%03.032.1( ±=
* Background contamination subtracted (~0.3% in MC preliminary)** 0.34% subtraction KPMFILT selecting nonK+K– events (MC)
(very preliminary estimation)
*
**
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
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Filter algorithm (I)Preliminary requirements
Cosmic Veto (DC+EMC) Trigger
Any of the 5 EvCl algorithms
a 2-tracks vertex in the DC involving a K± track
Distance between the two tracks’ first/last hit < 50 cm
Angle at vertex between the two tracks > 2°
K±±00 measuring branching ratio and Dalitz plot parameters
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
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Filter algorithm (II)Further requirements
4 “ontime” non-associated clusters coming from the charged vertex: |ti–tj–(Li–Lj)/c|<3t(Ei,Ej) i,j=1,..,4
Considered the best possible quartet of clusters: 80 MeV < m12,m34 < 190 MeV ( 3m cut )
Charged product track momentum: |pdau| < 135 MeV in K± frame
K±±00 measuring branching ratio and Dalitz plot parameters
all contamination ~0.4% (MC)
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
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Tagging strategies
1) K±±0
2) K±±
K±±00 measuring branching ratio and Dalitz plot parameters
Daughter momentum: 199 MeV < |pdau| < 211 MeV in K frame Missing mass at K vertex: 90 MeV < mm < 180 MeV 2 ontime non-associated clusters: 120 MeV < m < 150 MeV
all contamination ~0.35% (MC)
all contamination ~0.3% (MC)
Daughter momentum: 226 MeV < |pdau| < 245 MeV in K frame Missing mass at K vertex: |mm|< 5 MeV
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
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BR measurement method
BR(K±00) = 1Ntag
[Nobs ]tag
[ ]tag
±00
±00 tag = 0,
[ ]tag does not depend on FILFO , EvCl , tag
independence from trig to be tested
±00
K±±00 measuring branching ratio and Dalitz plot parameters
= K(pK) vtx(pK,p) 4clu(E) 2
pairing(E)
WORK IN
PROGRESS
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
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Efficiencies (Data and MC )
K±±00 measuring branching ratio and Dalitz plot parameters
K vs # of non-associated clusters
(non-tag, E > 20 MeV)All tag events sample
vtx (p)
00 events subsample
clu (E)
0 events subsample
WORK IN
PROGRESS
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
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Ratio o/
Ratio tagging
• peak window 225 MeV/c < PCM < 245 MeV/c
• peak window 195 MeV/c < PCM < 215 MeV/c
• Decay vertex with Rxy > 40 cm
• For good trigger efficiency : one kaon track has a decay o
• Cut for secondary vertex and secondary momentum 20 MeV/c <Psec < 400 MeV/c
• Cut for kaon momentum at decay
point 80 MeV/c < PK < 120 MeV/c
CMSmomentum spectrum for +K decay
+ – , e±0± 0, 0 0
o
M. Primavera2nd KLOE Physics Workshop, 10th-12th june 2002 Otranto (LE)
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Branching ratio of o,
Branching ratio cuts
• Number of K all caluclated as number of decays
in secondary monentum window from 20 to
400 MeV/c• Decay vertex with Rxy > 40 cm
• peak window and peak window
• Using only drift chamber information
MCKKN
MCallKN
dataallKN
dataKKN
BR),0(
)(
)(
),0(
υ
υ±→±±→±
→±
→±
±→±±→±
=
υ ±→±±→ KKPDG
,0