ICHEP04 Beijing 16-22 aug 2004 Rare Kaon Decays and CP, TCP Violation Vincenzo Patera* LNF/INFN...
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Transcript of ICHEP04 Beijing 16-22 aug 2004 Rare Kaon Decays and CP, TCP Violation Vincenzo Patera* LNF/INFN...
ICHEP04 Beijing 16-22 aug 2004
Rare Kaon Decays and CP, TCP ViolationRare Kaon Decays and CP, TCP Violation
Vincenzo Patera*LNF/INFN
*From KLOE collaboration
ICHEP04 Beijing 16-22 aug 2004
CP Violation and SM tests TCP Violation tests Detour to Vus
Outlook & Conclusions
CP Violation and SM tests TCP Violation tests Detour to Vus
Outlook & Conclusions
Foreword and outlineForeword and outline
The talk focuses on the experimental results of the last 2 years
Caveat: from an experimentalist point of view…!
Foreword: kaons again?In spite of a long history the K system is still a laboratory for the flavour physics, an interferometry system, a repository of all kinds of CP violation and can be a sensitive probe for NP.. Then:
YES, kaons again!
Notice: all the limits are at 90% C.L.
Blind analysis everywhere
ICHEP04 Beijing 16-22 aug 2004
Kaon and CP: classificationKaon and CP: classification
CP violation in the decay amplitute
CP violation in the decay amplitute
CP eigenstates ≠ mass eigenstates
CP eigenstates ≠ mass eigenstates
CP violation from interference of “DIRECT and MIXING”
CP violation from interference of “DIRECT and MIXING”
DIRECT MIXING or INDIRECT
INTERFERENCE
Ceccucci LP03
DIRECT CP firmly established after more than 30 yearsRe(’/) = (16.7±2.3)x10-4
KRe(’/)
ICHEP04 Beijing 16-22 aug 2004
Kaons, Unitarity Triangle(s) & CPKaons, Unitarity Triangle(s) & CP
11
21
21
23
22
32
AλiηρAλ
Aλ/λλ
iηρAλλ/λ
VVV
VVV
VVV
tbtstd
cbcscd
ubusud
The CP violation found its niche in the CKM mixing matrix and in its Wolfenstain parametrization. Up to O(4) the CKM is given by:
004.0)(
04.0
2.0
223
2
A
A
)1(52* AVV ttdts
A Unitarity Triangle stems from any complex unitarity costraint, but the unique measure of the CP in the CKM = 2xarea of any UT
JCP = Im(Vud*VusVts
*Vtd) ~ VusVud Im t
Unique CP parameter t probed by K or B sector differently: SM
test and/or NP sensitivity
If V*tdVts is complex CP is violated.. In shorthand:
ICHEP04 Beijing 16-22 aug 2004
The Unitarity Triangle and K rare decaysThe Unitarity Triangle and K rare decays
UnfortunatelyBR ranges from
10-8 to 10-11
KL→0e+e-
KL→0+-
KL→
KL→+-
KL→+-
KL→
KLee
KS→0e+e-
KS→0+-
KL→0
)0,1()0,0( )0,( 0
),(
K+→+-
Im t = A23 Re t= A23
The rare Kaon decays BR directly measure the UT, someone by itself, someone by the aid of ancillary K decays measurement.
ICHEP04 Beijing 16-22 aug 2004
Rare Kaon decays and SM test Rare Kaon decays and SM test
Yet, in spite of the experimental difficulty, the
rare K system:
Is theoretically clean (almost..)
Is highly sensitive to NP
Has different sensivity to NP wrt the B sector
Not only K ! NP sensitivity of KL0ll
system :Buras,Fleisher,Recksiegel,Schwab : hep-ph/0402112
SM test:sin2J/KS)
vssin2(K)
ICHEP04 Beijing 16-22 aug 2004
t and K++ t and K++
*1122
0411 10)1.17.7()(109.8)( AKBR SM
Negligible long distance effects 10-13
Hadronic matrix element via isospin rotation
K+e+0Reliable th. estimate from SM
Charm loop contribution = 0 1.4
*Isidori hep-ph/0307014
GOOD from a theorist point of view!!
)0,1()0,0( )0,( 0
K+→+),(
Im t = A23 Re t= A23
ICHEP04 Beijing 16-22 aug 2004
K++: E787/E949@BNLK++: E787/E949@BNL
end view
side view
KE949 wrt E787 improvement:
•Photon veto hermeticity•Tracking & energy resolution
•DAQ and trigger•Protons/sec from AGS
1210daccumulate
ratio
%factorduty
Tpintensity beam
KN
K 9.5
4
52
4025
8.1
3
41
70
E787 E949
Not optimal in 2002 run:•Spill duty factor
•Proton momentum•K/ electrostatic separators
ICHEP04 Beijing 16-22 aug 2004
K++@E949: detectionstrategy K++@E949: detectionstrategy
+ momentum in K+ frame (MeV)process Rate x 1010
K++ 0.77
K++ 2113000000
K++ 6343000000
K++0 327000000
+ from beam 25000000
Signal: a + from K+. No kinematic closure and
overwhelming bck.
700 MeV/c K+ stopped decay Detect pion from e decay chainMeasure everithing you can: range, momentum , energy, time
Signal: a + from K+. No kinematic closure and
overwhelming bck.
700 MeV/c K+ stopped decay Detect pion from e decay chainMeasure everithing you can: range, momentum , energy, time
12 weeks of data taking.Bck shapes modeled on data.
Each bck rejected by at least 2 independent cuts.
ICHEP04 Beijing 16-22 aug 2004
K++@E949the signalK++@E949the signal
E787 E949
NK+ 5.9x1012 1.8x1012
Accept.(20±2)x10-
3
(22±2)x10-
3
N. events 2 1
Total bck 0.14±0.05 0.30±0.03
K+ 0.064 0.068
K+ 0.032 0.216
Beam bck 0.050 0.014
E949
E787
Opening the box a new event is found
Background check: compare events predicted vs observed loosening one cut vs the other. Acceptance from MC verified
on K+ +0
ICHEP04 Beijing 16-22 aug 2004
K++@E949results K++@E949results
1096.0)( 1009.447.0
KBr
1030.189.0 1047.1)(
KBr
E949(02) = combined E787&E949.E949 projection with full running
E949 result (12 weeks of run)
E949 & E787 combined result
Analysis of the low momentum region (PNN2) in progress
Efforts to achieve on PNN2 a S/N 1 and sensitivity similar to PNN1
E949 was approved for 60 weeks of data taking more
stat?? (bad news…)
ICHEP04 Beijing 16-22 aug 2004
CP: Imt and KL0 CP: Imt and KL0
*11
2
4
3.2
110 10)5.06.2(10
Im
166
)(1048.1)(
ttt
SML GeV
mmKBR
Direct measure of Imt JCP
No long distance effects Only top loop contributionVery small theoretical error on SM
prediction Grossmann-Nir bound :
BR(KL0vv) < 4.4 x BR(K++)
< 1.4 x 10-9
*Isidori hep-ph/0307014
A dream for a theorist, a nightmare for an experimentalist. All neutral, 2/3 invisible final state: “Nothing to nothing”
)0,1()0,0(
KL→
Im t = A23
),(
ICHEP04 Beijing 16-22 aug 2004
KL0e+e-(+-) : KTeV @ TevatronKL0e+e-(+-) : KTeV @ Tevatron
• Charged particle momentumresolution < 1% for p>8 GeV/c;Momentum scale known to 0.01% from K.
• CsI energy resolution < 1% for E > 3 GeV; energy scale known to 0.1% from Ke.
•TRD system pion/electron ID
•KD with 0De+e- used
to normalize flux and acceptance.
KTeVMore than 20 years history..
ICHEP04 Beijing 16-22 aug 2004
KL0 @KTeV: the limitKL0 @KTeV: the limit
DataMC BG Sumn MC MCSignal MC
•1997 ’/ Data.•Analysis of events with Dalitz 0 decay.•Bck limited•4 order of magnitude higher wrt SM prediction
BR (KL)< 5.9x 10-7 (0ee)
PRD61(2000)
ICHEP04 Beijing 16-22 aug 2004
KL0 : E391a@KEK-PSKL0 : E391a@KEK-PS
Detector system
Pencil beam Detector with complete
veto systemo 4 coverage with thick
calorimetero Wide acceptance o Double decay chambero Operation in high vacuum
High PT + nothing selection
Step by step approach KEK-PS E391a JPARC
Pencil Beam
Firs detector designed for KL0veto, veto, veto..
ICHEP04 Beijing 16-22 aug 2004
Detector integration: Jan 22, 2004
Start of Run I data taking :Feb 18 2004
End Run I data takingJun 30 2004
KL0 : E391a detectorKL0 : E391a detector
ICHEP04 Beijing 16-22 aug 2004
KL0@E391a:Run I (2004)KL0@E391a:Run I (2004)
6- invariant mass (GeV/c2)
KL000
4- invariant mass (GeV/c2)
KL00
Expected
sensitivity by Run I:
4÷9x10-10
Results from Run I in fall 2004
Requesting Run II in 2005
ICHEP04 Beijing 16-22 aug 2004
CP : Imt from KL0e+e-(+-)CP : Imt from KL0e+e-(+-)
KL→0e+e-
KL→0+-
KS→0e+e-
KS→0+-
KL→0
Im t = A23
)0,1()0,0(
),(
The connection of the KL0e+e-() decays to t is not straightforward, but substantial
improvement of theory and experimental results have been in the last 2-3 years, expecially related
to ancillary modes
ICHEP04 Beijing 16-22 aug 2004
CP : Imt from KL0e+e-(+-)CP : Imt from KL0e+e-(+-)
KL0e+e-(+-) phenomenology:the decay amplitude has 3 ingredients:
3) CP conserving term via intermediate state
e+(+)
e-(-)
e+(+)
e-(-)
e+(+)
e-(-)
*Isidori,Smith,Underdorfer hep-ph/0404127Buchalla, D’Ambrosio,Isidori Nucl.Phys.B672(2003)
1) Direct CP term Im t , dominated by short distance
dynamics
2) Indirect CP term due to KL-KS mixing
Amplitude 2) can be extracted via from KS0e+e-(+-) decay while 3) can
be derived from KL0 data Direct and Indirect CP amplitudes can
interfere. In the past 2 years both precise
calculation for 1)* and new data for
KS 0e+e-(+) and KL0 appeared on the market
ICHEP04 Beijing 16-22 aug 2004
From KL0l+l- to Imt : KS0l+l-From KL0l+l- to Imt : KS0l+l-
330
)()()(
0020
llKBRllKBRllKBR S
SS
LmixCPVL
330
)()()(
0020
llKBRllKBRllKBR S
SS
LmixCPVL
e+(+)
e-(-)
Assuming the VMD the KS BR can be predicted of the
order:
*Buchalla,D’Ambrosio,Isidori Nucl.Phys. B(2003)
BR(KS0e+e-) 5 x10-9
BR(KS0+-) 1 x10-9
KL0l+l- CP mixing contribution ( and
interference) can be evaluated via and the corresponding KS0l+l- amplitude*.
ICHEP04 Beijing 16-22 aug 2004
LKr Calorimeter:(E)/E (E)/E 3.2%/√E 3.2%/√E 9%/E 9%/E 0.42%0.42%(t) (t) 265 ps for 50 GeV e 265 ps for 50 GeV e
Spectrometer:pT kick ~250 MeV/c(P)/P (P)/P 0.48% 0.48% 0.009 P[GeV/c] 0.009 P[GeV/c]%%
Muon system:Muon system:(t) (t) 350 ps 350 ps
M(00) ~ M(+-) ~ 2.5 MeV
KS0e+e-(+-) : NA48/1 @CERN KS0e+e-(+-) : NA48/1 @CERN
KS beam : 2000 (only s) and 2002
run
More than 20 years history..
ICHEP04 Beijing 16-22 aug 2004
From KL0l+l- to Imt : KS0l+l-From KL0l+l- to Imt : KS0l+l-
Dataset: 3.51 x1010 KS decays with < 2.5S and 40<EK<240
GeVMain Backgrounds
For e channel: KS00D with a
lost:rejected by mee> 0.165 GeV/c2
cut
time accidentals , mainly from lv + 00(0): studied from time side bands
KL,Se+e- Greenlee background
due to double radiation:
estimated from 2001 KL run
(statistics x10). Negligible for the channel
Bck source Events
KL,Se+e- 0.08+0.03-0.02
Accidentals 0.07+0.07-0.03
Total bck 0.15+0.10-0.04
Bck source Events
KL,S+- 0.04+0.04-0.03
Accidentals 0.18+0.18-0.11
Total bck 0.22+0.18-0.11
KS0e+e-
KS0+-
ICHEP04 Beijing 16-22 aug 2004
From KL0e+e- to Imt : KS0l+l-From KL0e+e- to Imt : KS0l+l-
BR(KS ee) = 2.8 92.3(5.8 0.8 ) x 10syststat
[PLB576 (2003)]
Assuming vector interaction and unity form factor for electron channel to recover the mee>0.165 GeV/c2
MK(G
eV
)
M(GeV)
7 signal events
M(GeV)
M
(GeV
)
6 signal events
BR(KS 1.4 91.2(2.9 0.2 ) x 10syststat
KS0e+e- KS0+-
CERN-PH-EP/2004-025
ICHEP04 Beijing 16-22 aug 2004
KL0e+e-(+-) : SM predictionKL0e+e-(+-) : SM prediction
The last ingredient is the CP conserving amplitude of KL0l+l- . It can be parametrized
in term of :
BR(KL0) =(1.36±0.03stat±0.03sys±0.03nor)x10-6 *
=(1.68±0.07stat±0.08sys)x10-6 **
e+(+)
e-(-)
0++,2+
+
*Isidori,Smith,Unterdorfer hep-ph/0404127
**Friot,Greynat,de Raphael hep-ph/0404136
2
4,
4,
int,,0
10
Im
10
Im)(
tedir
teemix
ecpcSML CCCCllKBR
The t parameter dependence is embedded also in the interference term. The positive sign of the interference term seems to be theoretically preferred*,**
BR(KL0) BR(KS0ll)
*NA48 PLB2002 **KTeV PRL1999
Finally:
theory
ICHEP04 Beijing 16-22 aug 2004
KL0e+e-(+-) : SM predictionKL0e+e-(+-) : SM prediction
BR(KL0 e+ e-)SM x 1011 = (3.1 or 1.3)
±1.0
BR(KL0 + -)SM x 1011 = (1.8 or 1.2)
±0.3
Taking Im(t) = (1.36±0.12)x10-4 a prediction can be done for BRs:
Interf (-)
Interf (+)
Contribution to BR
BRs vs Imt
Main uncertainties come from experimental inputs and (less)
from CPC contribution theoretical evaluation (
channel)
x10-12
ICHEP04 Beijing 16-22 aug 2004
KL0e+e- @KTeV: backgrounds KL0e+e- @KTeV: backgrounds
Background due to KL0 ,
KLDKLev is removed
using TRD and cut on charged momenta and event pt
2
•Irriducible background with same final state of the signal from Greenlee double radiation: KLe+e-
with a BR=(6.31 ± 0.14 ± 0.42)x10-7
•The background has radiative s collimated with e±. Discrimination via minimum angle between and e
•The signal has almost isotropic s in the 0 frame. Discrimination via angle between and KL in 0 frame
1997+1999 dataset: 6.7x1011 KL
Mee (GeV/c2)
M
(G
eV
/c2)
1999data
Signal: two s and two opposite tracks with e IDs
ICHEP04 Beijing 16-22 aug 2004
KL0e+e- @KTeV:resultsKL0e+e- @KTeV:results
Opening the box after these cuts 1 events is found out of 1 ±1/3
background events expected. The limit obtained is:
BR(KL → 0 ee ) < 2.8 × 10-10 @90%CL
Mee (GeV/c2)
M
(G
eV
/c2)
1999data
Phys. Rev. Lett. 93, 021805 (2004) 1997+1999 data
2 order of magnitude lower than the previous limit but 1 order of magnitude higher then the SM prediction. Future
measurement will need improvement both in KL statistic and in background rejection
ICHEP04 Beijing 16-22 aug 2004
KL0+- @KTeV: backgroundsKL0+- @KTeV: backgrounds
A similar analysis has been made for KL0+- on the 1997
dataset: 2.7x1011 KL
Signal: two s and two opposite tracks with IDs Background mainly due to KL0,KLv +2acc and to
double radiative KL+-.
the Greenlee bck is less severe than for e+e- case ( the radiates less):
BR(KL+-) = (10.4+7.5-5.9
±0.7)x10-9
M (GeV/c2)
Pt2 (
GeV
/c)2
Kinematic costraint on inv. mass and pt of total event
single out the signal
ICHEP04 Beijing 16-22 aug 2004
KL0+- @KTeV: resultsKL0+- @KTeV: results
BCK mode Expected ev
total 0.87±0.15
KL+- 0.373±0.032
KL0+- 0.268±0.096
KLacc 0.161±0.093
Even
ts/1
MeV
M (GeV/c2)
Opening the box 2 events were found in the signal region with 0.87
expected
The limit obtained is:
BR(KL→ 0 ) < 3.8 × 10-10
@90%CL
Phys. Rev. Lett. 84, 5279-5282 (2000)1997 data
Also the KL0+- exp. limit
has been pushed down by orders of magnitude but is still ~1 order of magnitude above SM
ICHEP04 Beijing 16-22 aug 2004
Kaon rare decays and Re(t) Kaon rare decays and Re(t)
)0,1(
•The BR(KL) is almost saturated by the absortive amplitude, computed from measured BR(KL) with small error. •The (tiny) short distance contribution of dispersive amplitude is related to :
),(
9
255.1
2 10040.0170
)()2.1()(
cbtt
SDL
V
GeV
mmKBR
The long distance contribution to dispersive amplitude, via KL*, KL**, must be
extracted from KLl+l- and
KLe+e-l+l-dataKL→+-
KL→
KL→ee)
KLeeee(
KL→
KL→ee)
KLeeee(
Ret= A23
ICHEP04 Beijing 16-22 aug 2004
Re(t):KL and E871@BNLRe(t):KL and E871@BNL
Accuracy limited by the error (th. & exp.) on dispersive amplitude evaluation
BR(KL) = (7.18 ±0.17)x10-9
< 0.33 @90% C.L. PRL84(2000)
signal
bck
E871Muon hodoscope
Lead GlassCalorimeter
CerenkovTrigger
Scintillator
NeutralBeam Dump
Drift Chamber 5 & 6
Straw Chamber 1 & 2
Drift Chamber 3 & 4
ICHEP04 Beijing 16-22 aug 2004
UT and CP from K: status summaryUT and CP from K: status summary
K++ : BR twice of SM prediction but within statistical error. (new run?)
KL0 : exp. limit far
away from SM, but E391a is getting closer.
KL0ll : experimental
limits a factor 10 above SM. New exp. needed (may be KL0 easier?)
KL : sensitivity to limited both by theory and by exp. error on KL→ f.f.
Courtesy of G.Isidori
New generation of dedicated
experiments (& beams) needed.
ICHEP04 Beijing 16-22 aug 2004
OutlineOutline
CP Violation and SM tests TCP Violation Detour to Vus Outlook & Conclusions
CP Violation and SM tests TCP Violation Detour to Vus Outlook & Conclusions
ICHEP04 Beijing 16-22 aug 2004
Main uncertainty on CPT violating parameter is due to the
error on A(KS30) and on |000|=A(KS30)/A(KL30)
contribution to :
Rare Kaon decays and TCPRare Kaon decays and TCP
ff
LS
LS im
i )Im()Re()(
21 ,
A TCP test typical of the Kaon system can be derived from the KL,S amplitudes imposing unitarity via the Bell-Steinberger
relation:
*1f S L
S
A K f A K f
The experimental limit on BR and in literature are:
BR(KS30) < 1.4x10-5 (SND, PL B459 1999)
Im = (2.4 ± 5.0) × 10-5 CPLEAR ’99
0000
000 3Im
L
SLKBR
ICHEP04 Beijing 16-22 aug 2004
KS30 : KLOE@DANEKS30 : KLOE@DANE
KLOE run 2001-20020.45 fb-1 1.4x109 decays
Foreseen 2 fb-1 2005
KLKS 106 /pb-1 p* = 110 MeV/cS = 6 mm L = 3.4 m
•The decay at rest provides pure, monochromatic, back to back kaon beams in 1-- quantum state •Tagging: observation of KS,L signals presence of KL,S
•KL,S beams in the same detector at the same time
K+K- 1.5 106 /pb-1 p* = 127 MeV/c ±= 95 cm
KKLL tag tagByByTOFTOF
KKSS ee
m=1019.4 MeVThe KS→30 is a CP violating
decay, with a BR in the SM ~1.9x10-9. The -factory provides
an abundant pure KS beam
ICHEP04 Beijing 16-22 aug 2004
KS30 : KLOE@DANE KS30 : KLOE@DANE
p/p = 0.4 % (tracks with > 45°)
vertex ~ 1 mm
(M) ~ 1 MeV
E/E = 5.7% E(GeV)
t = 54 ps /E(GeV) 50 ps (relative time between clusters)
L() = 2 cm ( from KL )
Drift chamber (4 m 3.3 m)90% He + 10% IsoB, CF frame12582 stereo sense wires
Electromagnetic calorimeterLead/scintillating fibers 4880 PMT’s
Superconducting coil (5 m bore)B = 0.52 T ( B dl = 2 T· m)
ICHEP04 Beijing 16-22 aug 2004
KS30 @KLOE: results KS30 @KLOE: results
4 candidates in signal box with 3.2±1.4±0.2 expected by bck (MC)
BR(KS30 ) < 2.1x10-7 @90% CL (KLOE04 PRELIMINARY)*
BR(KS30) < 7.4×10-7 @90%C.L. (NA48 ’04 hep-ex/0408053)
KS tagged by KL which
interacts on EMC (~30%). The KL interaction are
identified by energy and . KS signal selected by 6 sMain bck from KS20 + acc.Event fitted in 30 and 20 hyphothesis
6
000Im 6.34 10 @90% . .C L
Im() = (-0.2±2.0)x10-5
Accuracy limited by A(KL,S→+-)
23
• Data• MC 2
22
*This conference
ICHEP04 Beijing 16-22 aug 2004
OutlineOutline
CP Violation and SM tests TCP Violation Detour to Vus Outlook & Conclusions
CP Violation and SM tests TCP Violation Detour to Vus Outlook & Conclusions
ICHEP04 Beijing 16-22 aug 2004
Detour: a look at the Vus sagaDetour: a look at the Vus saga
BUT (in 2002) ... BRs obtained from fit to ratios of BRs. Errors and
central values to be checked 3/e3 disagreement with measured ff slopes, 4% or
3 Unknown inclusion of radiative processes
222
3
5
3(
191 (0)
2)EW K us K
KK
F S fV IG M
No theory ! No ’s ! No hyperons ! Only K measurements !
2002: after a huge revision of the Vud determination (th. & exp.)
according to PDG: |Vud|2+|Vus|2+|Vub|2 |Vud|2+|Vus|2 = 1-2.4The preferencial source of Vus being Kl3 decay (Ko & K+):
theory
From experiment: BRs, lifetimes and form factors to compute and IlK
ICHEP04 Beijing 16-22 aug 2004
Vus after 2002: new measurementsVus after 2002: new measurements
2003 – E865: BR(K+ e2004 – KTeV: main 6 KL BRs and Kl3 f.f.
2004* – NA48: BR(KLe), BR(K±0e±) and
f.f.2004* – KLOE: BR(KSev) , BR(KLl) and
(KL)
fully inclusive measurements: Ke(),
*this conference
**Czarnecki,Marciano,Sirlin hep-ph/0406324
The new Vus seem to amazingly agree with unitarity in spite of
a bit of “entropy”.. For example in the KL(e) case:
L(10-7s) f+(0) f.f.
KTeV 51.50 0.961quadraticmeasured
NA48 51.50 0.981linear
measured
KLOE 51.35 0.961 as KTeV
KSe3 KL3 KLe3 KLe3 KLe3 K+e3 K+e3
**|Vus|
KLOENA48KTeVE865
ICHEP04 Beijing 16-22 aug 2004
Vus saga: BRs vs form factorsVus saga: BRs vs form factors
BUT agreement of new Vuss gets even better if the same ingredients (but the BRs) are used for Vus*→BRs seem ok!
Less agreement on new measured form factors. Notice: linear vs quadratic f.f. can account as much as 1% on Vus.
*F.Mescia,A.Antonelli, this conference
from PDG04f.f. by KTeV.
Vu
s x f
+(0
)
KTeV NA48 ISTRA**
+’ x10-
3
20.64 1.75
28.81.2 23.24 ± 1.52
+’’ x10-3
3.20 0.69 0 1.62 0.79**2”ISTRA=”KTeV
2004 results
•PDG02
ICHEP04 Beijing 16-22 aug 2004
Vus and Kaons: something newVus and Kaons: something new
Alternative method to extract Vus from K±±: given fK/fp
computed on lattice, then:
(K2) is from a 1972 measurement and PDG fit. It is not known
what radiative contribution is retained. Adding contribution of radiation |Vus| goes up! New measure? (KLOE,NA48,ISTRA)
♦ ffKK/f/f-1=0.210(4)(13)-1=0.210(4)(13) |V|Vusus| =(0.2219| =(0.2219((MarcianoMarciano hep-ph/0406324) hep-ph/0406324)((MILCMILC hep-lat/0407028) hep-lat/0407028)
lattice theoryexp
ICHEP04 Beijing 16-22 aug 2004
OutlineOutline
CP Violation and SM tests TCP Violation Detour to Vus
Outlook & Conclusions
CP Violation and SM tests TCP Violation Detour to Vus
Outlook & Conclusions
ICHEP04 Beijing 16-22 aug 2004
Outlook: KOPIO@BNLOutlook: KOPIO@BNL
•Microbunched flat beam: measure velocity (momentum 800 MeV/c) of KL
•Hermetic high efficiency veto•Measure time, position and energy •High vacuum decay region
Aim to collect 60 KL→0 events with S/B~2
(Im t to 15%)
Approved & fundedAdvanced R&D
Construction start 2005 (?)
KL→0
ICHEP04 Beijing 16-22 aug 2004
Outlook: E391@JPARKOutlook: E391@JPARK
Evolution of the E391a@KEKPencil beam conceptTarget sensitivity well beyond SM prediction for
KL0Start in 2009(?)KEK-PS AGS JPARK-1
E(Gev) 12 24 30
Duty cycle(s)
4.0 6.4 3.4
I(A) 0.1 1.63 9.5
spill(s) 2 4.1 0.7
Duty factor 0.50 0.64 0.20
Rate (1012/s) 1.3 16 286
JPARK
KL0
ICHEP04 Beijing 16-22 aug 2004
Outlook: NA48/3@CERNOutlook: NA48/3@CERN
Based on upgrade of NA48/2 detector
Unseparated, positive beam of 75 GeV/c with P/P~1%
Upstream detector to identify kaons and measure K momentum
Hermetic photon vetoes Finely segmented Hadron
Calorimeter/Muon veto• EoI exists• Intense R&D activity in 2004 • time schedule Villars Workshop in fall 2004
Goal: About 50 Events with a Goal: About 50 Events with a S/B of 10:1 in 2 years of data S/B of 10:1 in 2 years of data
takingtaking
K+ +
ICHEP04 Beijing 16-22 aug 2004
Outlook: further initiatives/projectsOutlook: further initiatives/projects
K+ physics at the JPARK charged beam (2009)
Pure KS beam – factories (schedule?)
Four LOI presented addressing K++ , T violation in K+
3 , rare K+ decays , K+e3 BR with high
statistic
Clean environment to study KS decay: CP, TCP violation and KS0l+l- . DAFNE-2 (?) project, dedicated workshop
in Alghero in 2003
OKA@Protvino: RF-separated K± beam project (schedule?)
Rare K± decays physics, direct CP violation in K± ±± and K±±
ICHEP04 Beijing 16-22 aug 2004
ConclusionsConclusions
The field of rare kaon decays is quite active. A generation of detectors is now mature (’/, LFV, T violation) and a new
round of initiatives is approaching.
Projects are addressing both neutral and charged K. Despite of the experimental difficulty this item will be on the spot in the next years.
New (coherently on KS & KL) projects/ideas are needed to explore the KL,S0ll system. Interference with mixing CP amplitude enhance both direct CP signal and sensitivity to NP. Mostly exp. limited..Why not? (expecially the mode..)
The Vus saga seems to have an happy end. New results in better agreement with unitarity. Focus now on f.f. and K0, K+ lifetimes
ICHEP04 Beijing 16-22 aug 2004
Further results on rare K decays and TFurther results on rare K decays and T
T violation: E246@KEK-PS. Final results (2004) from K+0:PT = (- 1.7 ± 2.3stat ± 1.1syst)x10-3
Lepton Flavor Violation: KLe E871@BNL.
BR(KL→ e) < 4.7 10-12 90% CL
Lepton Flavor Violation: K++e- E865@BNLBR(K+++e- ) < 1.2 x 10-11
Dalitz decay @ KTeV : BR(KL→ee) = (2.69± 0.24± 0.12) x 10-9
BR(KL→eeee) = (4.16 ± 0.13 ± 0.13 ± 0.17) x 10-8
And many more……..
TCP violation: KS semileptonic asymmetries @KLOEAS = (2 ± 9stat ± 6syst) x 10-3 KLOE2004 (preliminary)
ICHEP04 Beijing 16-22 aug 2004
OutlineOutline
CP Violation TCP Violation T Violation Lepton Flavour Violation Outlook & Conclusions
CP Violation TCP Violation T Violation Lepton Flavour Violation Outlook & Conclusions
Caveat: all that from an experimentalist point of view…!
Notice: all the limits are at 90% C.L.
ICHEP04 Beijing 16-22 aug 2004
K decays and T violation: E246@KEK-PSK decays and T violation: E246@KEK-PS
SM expectation: PT 10-7
Final results (2004) from K+:PT = (- 1.7 ± 2.3stat ± 1.1syst)x10-3
Side product from K+→ : PT = (-6.4 ± 18.5stat ± 1.0syst)x10-3 *
transverse polarization in K+
3
Stopped K+ experiment with a SC toroidal spectrometer Measurement of all decay kinematics directions+ separation from e+ by TOFEvents selected by +,0 coincidence
*Phys.Lett. B562 (2003) 166]
ICHEP04 Beijing 16-22 aug 2004
OutlineOutline
CP Violation TCP Violation T Violation Lepton Flavour Violation Outlook & Conclusions
CP Violation TCP Violation T Violation Lepton Flavour Violation Outlook & Conclusions
Caveat: all that from an experimentalist point of view…!
Notice: all the limits are at 90% C.L.
ICHEP04 Beijing 16-22 aug 2004
LFV: KLe E871@BNLLFV: KLe E871@BNL
BR(KL→ e) < 4.7 10-12 90% CL Signal region
Control region0.1 bck event expectedin the 1995-96 data sample , no events observed :
Main background from K0L→ e with → decay in
flight and e scattered on vacuum window and first tracking station. Rejection by cut in M(e) vs pt
2 plane
ICHEP04 Beijing 16-22 aug 2004
LFV: K+e- E865@BNLLFV: K+e- E865@BNL
Dataset 1995-96-98
Main background from time accidentals, estimated by time sidebands = 8.2±1.9 events expectedLikelihood analysis built on beam parameters, PID, timing and three-track invariant mass
BR(K+++e- ) < 1.2 x 10-11
E865
Far away from SM expectationsHard competition by experiment
ICHEP04 Beijing 16-22 aug 2004
TCP test : KSe0 asymmetry@KLOETCP test : KSe0 asymmetry@KLOE
e e
Emiss–cPmiss(MeV) Emiss–cPmiss(MeV)
AS = (2 9stat 6syst) x 10-3 KLOE2004 (preliminary)
AL = (3.322 ± 0.058 ± 0.047) x 10-3 KTeV 2002
Efficiency evaluated using KL edecaying close to IP: e+) = (24.10.1 0.2)% e-) = (23.60.1 0.2)%
PID from TOF
)()(
)()(
,,
,,,
eKeK
eKeKA
LSLS
LSLSLS
AS -AL= 0 if TCP holds
TCP test is also made using the KL,KS semileptonic asymmetries:
First measuremen
t
ICHEP04 Beijing 16-22 aug 2004
Vus & BRs: what is actually measured?Vus & BRs: what is actually measured?
Exp Quantity measured channel
KTeVR(e3/3), Re3/00), Re3/000),
Re3/0-+), R(00/000)
KLe
KL
KLOE
Absolute BR(K3) using KS tag KL
Absolute BR(Ke3) using KS tag KLe
BR(KSe)/BR(KS) KSe
E865 BR(K±e±0D)/BR(K±( ±0
D+ ± 0D+ ±0
D))*K+e+
NA48BR(K±e±0
D)/BR(K±( ±0D+ ± 0
D+ ±0D))*
K+e+
BR(Ke3)/BR(k 2 tracks)BRe3/BR KLe
*BR(±0) PDG=21.13±0.14 dominated by 1 exp: CHIANG (1972) 21.18±0.28
R(a/b) = BR(a)/BR(b)
A lot of diffferent normalizations to PDG fit, PDG average, WA, etc. etc. are around
0Dee
ICHEP04 Beijing 16-22 aug 2004
Rare Kaon decays and TCP: KS30 Rare Kaon decays and TCP: KS30
20 0 93 3 1.9 10SS L
L
BR K BR K
BR(KS30) < 7.4 × 10-6 @90%C.L. (NA48 ’04hep-ex/0408053)
Within SM the KS30 violates CP and can be computed as:
NA48 searched for this decay exploiting the interference of KL-KS beams to enhance the rare KS30 decay with the much more abundant KL 30. The decay intensity is then
given by:
2
)(
000000
2
000
)sin()Im()cos()Re()(
)(LS
SL
emtmtpD
eetI tt
D(p) is the dilution factor to the KS to KL beam. Using he 2000 data the limit on the BR(KS→30) obtained is:
ICHEP04 Beijing 16-22 aug 2004
Improved photon veto
detectors γline beam New
2.3 add
region barrelin r calorimete New
0
X
rejection π0
E949
E787 2
Rejection to background as a function of acceptance for E787 and E949. better rejection at 80% of nominal acceptance.
2~
2K
γNew detectors in blue.
ICHEP04 Beijing 16-22 aug 2004
Trianglety on Unitari )(K ofImpact B
By courtesy of G. Isidori
Central value [dashed], 68% interval [dot-dashed], 90% interval [solid](including theoretical uncertainties)
3352 1008110240:)1(
0271000550
.λ.iλAVV λ
.V.
t-
td*
ts
td
ICHEP04 Beijing 16-22 aug 2004
From KL0+- to Imt : KS0+-From KL0+- to Imt : KS0+-
Main backgrounds from accidentals and radiative KL decay
The Greenlee background in the signal acceptance is reduced wrt the KLee case. Can be safely evaluated from KTeV
measurement:In the signal box 0.18+0.18
-0.11 events are expected
The 2 main source of accidentals are
KL→ + KS→
KS→ + KS→Contribution to signal estimated from time side band : 6 events in ~125 ns. In signal time window (3 ns) are
expected 0.18+0.18-0.11 of background
M(GeV)
M
(GeV
)
Out of time ev. (125 ns)
ICHEP04 Beijing 16-22 aug 2004
NA48 Detector & Data Taking NA48 Detector & Data Taking
1997
1998
1999
2000
2001
2002
2003
NA48: ’/
’/
’/
’/ lower inst. intensity
NA48/1 KS
NA48/1: KS
KL
no spectrometer
NA48/2: K
1996Total: 5.3M KL00
Magnetic spectrometer
Liquid krypton EM calorimeter2004NA48/2: K
ICHEP04 Beijing 16-22 aug 2004
KL0e+e- @KTeV: backgrounds KL0e+e- @KTeV: backgrounds
Rejection of the bck can be achieved exploiting the different kinematics:
•The background has radiative s collimated with e±. Discrimination via minimum angle between and e min
•The signal has almost isotropic s in the 0 frame. Discrimination via angle between and KL in 0 frame |cos()|The region where the bck is
concentrated is cut away.
KL0e+e-
min
|cos()|
KLe+e-
min
|cos()|
ICHEP04 Beijing 16-22 aug 2004
Re(t):KL and KL Dalitz decayRe(t):KL and KL Dalitz decay
2 2 2 22 2 1 2 1 21 2 2 2 2 2 2 2 2 2
1 2 1 2
( , ) 1( )( )DIP
q q q qf q q
q m q m q m q m
Two LD dispersive amplitude parametrizations:
BMS**: pseudoscalar/vector contributions: K
*
DIP*: general parametrization compatible with CHPT expansion: DIPDIP
DIP=-1+(3.1±0.5)K*
*D’Ambrosio,Isidori,Portoles PLB(1998) **Bergström, Massó, Singer, 1983
KL→ee) K*, DIP KLeeee(
DIP
Measures dominated by KTeV and NA48, no enough statistic for DIP
K
*
ICHEP04 Beijing 16-22 aug 2004
Unitarity Triangle(s): B vs K sectorUnitarity Triangle(s): B vs K sector
UT from K
UT from B
UT from K
UT from B
Not yet on scale!
Kaon UT is extremely squeezed due to t=V*tdVts .
Unique measure of the CP in the CKM = 2xarea of
all UT JCP = Im(Vud*VusVts
*Vtd) ~ VusVud Im t
Unique CP parameter t probed from K or B sector
with different loops: SM test and/or NP sensitivity