STATUS OF KLOE

F. Bossi,

CSN1

Frascati, May 13 2002

KLOE-LNF

KLOE SUBMITTED PAPERS

Study of the decay with April 24 hep-ex0204013 the KLOE detector Study of the decay with April 24 hep-ex0204012 the KLOE detector

Measurement of May 9 hep-ex0204024 (Ks +-()) / (Ks 00)

Measurement of the b.r for the April 10 PLB 535, 37 decay Ks e hep-ph0203232

Accepted Reference

Based on year 2000 data : 17 pb-1 analyzed / 23 collected

KS SEMILEPTONIC DECAYS

Motivation: If (CPT ok) .AND. (S=Q at work): (KS e ) = (KL e ) BR(KS e ) = BR(KL e ) x (L/S) = ( 6.704 ± 0.071 ) x 10-4

(using all PDG information). Only one measurement 75 events (CMD-2 1999): = ( 7.2 ± 1.4 ) x 10-4

Selection procedure Vertex with two tracks from I.P. kinematics (against huge “background”) time of flight ( electron vs pion) final signal variable = Emiss-|pmiss|

ToF selection illustrated for MC events

2. KS e

1. KS + Paper dedicated to the memory of L. Paoluzi

BR(KS e ) = (6.91 ± 0.34stat ± 0.15syst) x 10-4

2000

Motivations: First part of double ratio Extractions of Isospin Amplitudes and Phases A0 A2 and 0-2 consistent treatment of soft in KS +- () (PDG data contain ambiguities)

[Cirigliano, Donoghue, Golowich 2000]

3.KS 00

neutral prompt cluster (E>20 MeV and (T-R/c) < 5t ) at least 3 neutral prompt clusters (0 e+e- included)

(KS +-) / (KS 00)

Selection procedure: 1. KS tagging 2. KS +-() two tracks from I.P +

acceptance cuts: fully inclusive measurement (E*) from MC folded to theoretical spectrum

Contribution to systematic error

%

KS /KS tag 0.55

photon counting 0.20trigger and t0 0.23tracking 0.26Overall systematic error

0.68

KLOE 2000 data 2.236 0.003stat 0.015syst fully inclusivePDG 2000 2.197 0.026 ( without clear indication of E

cut )

(KS +-) / (KS 00)

Motivations: f0, a0, not easily interpreted as qq states; other interpretations suggested: qqqq states (lower mass) [Jaffe 1977]; KK molecule (m(f0,a0)~2m(K)) [Weinstein, Isgur 1990]; f0(980) , a0(980) and lowest mass scalar qq nonet [Tornqvist 1999] f0 , a0 sensitive to f0,a0 nature [Achasov, Ivanchenko 1989]: phenomenological framework (kaon loop model) coupling constants

g(KK) from (K+K-) g(f0KK) g(a0KK) f0, a0 model g(f0) g(a0) M() M() spectra

f0,a0

Kaon loop final state

radiative

Scalar Meson + [f0(980) I=0, a0(980) I=1]

f0 momentum depends on structure

Main background sources (5 final states): e+e 0 Other background sources (not 5 final states): or

Selection procedure: 5 prompt E > 7 MeV kinematic fit (without mass const.) Result: Nev = 2438 61 BR()=(1.09 0.03stat 0.05syst)x10-4

CMD-2 (0.92 0.08 0.06)x10-4

SND (1.14 0.10 0.12)x10-4

Fit to the M spectrum (kaon loop): contributions from f0 + “strong” negative interference negligible contribution

Fit results: M(f0) = 973 1 MeV g2(f0KK)/4 = 2.79 0.12 GeV2

g(f0) /g(f0KK) = 0.50 0.01

g() = 0.060 0.008

BR( f0) = (1.49 0.07)x10-4

Measured in 2 final states: (Sample 1) (5) is the main background 5 selection (see ) + kinem. fit (Sample 2) (2t + 5) Negligible bckg with the same topology: e+e 0 2t + 4KSKL (KL prompt decay) 2t + 4/6 2t + 5 selection + kinem.fit

Results: (Sample1) Nev = 916 Nbck = 309 20 BR() = (8.5 0.5stat 0.6syst)x10-5

(Sample2) Nev = 197 Nbck = 4 4 BR() = (8.0 0.6stat 0.5syst)x10-5 CMD-2 (9.0 2.4 1.0) x 10-5

SND (8.8 1.4 0.9) x 10-5

Combined fit to the M spectra: dominated by a0 negligible

Fit results: M(a0) = 984.8 MeV (PDG) g2(a0KK)/4 = 0.40 0.04 GeV2

g(a0) /g(a0KK) = 1.35 0.09

BR( a0) = (7.4 0.7)x10-5

A PAPER TO COME:

Measurement of BR(’)/BR( ) gives most accurate determination of pseudoscalar mixing angle to date:

7151

7.15.1

714

0.40..P

P

.θ

(flavor basis)

(octet-singlet basis)

gluonium content for the ’ < 10%

KLOE 2000 data

BR()

hep-ex 0107022, KLOE coll.

(flavor basis)(octet-singlet basis)

BR(’)/BR( ) = (5.3 0.5stat 0.3syst) ·10-3

using PDG value for BR() we obtain:

BR(’) = (6.0.6stat 0.5syst) ·10-5

Preliminary

KLOE 2001 DATA TAKING CAMPAIGN

Successful in terms of Ldt

About 175 pb-1 collected 110 days of run Best day: 3 pb-1 / 24 h

Painful in terms of backgrounds

Online bckg counter rates > by factor 2-5 wrt 2000 data

How much of this can we really use ?

LPEAK = 5 1031 cm-2 s-1

LAVG = 3.5 1031 cm-2 s-1

2001 DATA ANALYSIS

Repeat previous

Charged kaon decays

Determine KL BRs :

KS

KS

Under way (see next)

Feasibility study

Measurement of HAD to 1%

e.g. KL

IMPROVE 2000 ANALYSIS

KS +– / KS 00 :

As a part of double ratio, goal in accuracy is 1‰ ( 7‰ now)

Most of efficiencies determined by data

(KL +–0 , …) system. scale ~ statistics

KS e

Together with KL e tests S = Q and CPT

Also we can start looking at leptonic asymmetry

This can last forever…

KL

Goal : improve present accuracy of 2.5%

Strategy : determine BR from (KL (KL

known to 1.3% acc. (PDG)

Motivation : Useful in computations of rare KL decays

(KL +– …)

( PDG: dominated by NA31 (KL (KL

Status : Analyzed ~ 100 pb-1

Selected 5648 ± 85 KL events(good agreement with MC efficiencies)

No big problems from machine background due to highly kinematically constrained events

Final result expected by summer 2002

KL

Signature : Neutral vertex with 2 () or > 4 (30)‘s attached in KS +– tagged events

KL

M(MeV/c) KL(ns)

30 cm 150 cm

Preliminary

Preliminary

CHARGED KAON DECAYS

Together with KL decays determine sinC to a fraction of 1%

Many channels remain poorly known

Also remeasure all BRs for all channels Measure (e+e- ) ( BR( K+K–) ~ 50% )

KLOE profits of the unique feature of tagging

By looking at K+

or K+ 6 x 105 tags/pb-1

Preliminary results expected by summer 2002

Can verify validity of hadronic corrections

Tagging

Tag

Machine background

M

P

2001 DATA REPROCESSING CAMPAIGN

Reasons for reprocessing:

Updated calorimeter calibration

Revised physics filter algorithms

Bugs fixes

Production of compressed format DST’s for physics analysis ( factor ~ 6 data reduction)

18.1 GTriggers 52825 Files 49 TB Raw Data

First time we try a massive reprocessing !

(charged kaons, neutral kaons, luminosity)

3.5

2.5

1.5

Feb. 15 May 7

Processed luminosity(pb-1/day)

Processed triggers( kHz)

Day by day Y2001 Data Reprocessing

Started end January, completed beginning of May

Almost all DST produced, but charged kaon stream

2001 DATA REPROCESSING STATUS

Y2001 Data set -CPU power cost and data volumes stored for different data taking conditions

Data Taking Period

Dafne luminosity

(cm-2 s-1)

Sample Luminosity

( pb-1)

Maximum reconstructable

luminosity

(pb-1/day)

Data volume

(Gbytes/pb-1)

Nov-Dec 01 4 1031 51 3.5 400

Sep-Oct 01 2 1031 51 2.5 480

Jun-Jul 01 0.8-1.0 1031 58 0.9 600

00- Apr 01 0.5 1031 22 0.5 1200

The entire data amounts to about 105 Tbytes, i.e. 2650 filled cassettes, corresponding to 54% of the Tape Library storage space.

2001 DATA SET

2002 RUN SCHEDULE

February : Machine startup

March 11 – April 28 : DEAR run

April 29 : Start of KLOE run

Very encouraging results !

…

From last SC recommendations:

…to be revised on April 23/24

Expectations for the Kloe Run

From DANE team

Following DEAR experience:

Improvements can be obtained both in L and backgrounds:

• from sextupoles optimization• from octupoles insertion• from lattice changes• from better orbits• from new scrapers

Hopefully improvement of L by a factor of ~ 4 within ~ 5 weeks

START OF YEAR 2002 KLOE RUN

Smooth run start:

Detector 100% working (including DC ADCs)

DANE delivering ~ 1.5 pb-1/d

Backgrounds lowered by factor ~ 2

Present acquisition rate : 1.5 kHz

Computing & Data Storage 2002

0.04 nb-1 s-1 300 Bhabha s -1

1200 Bck s-1

1.5 KHz Trigger Rate 2.6 Kbytes/trigger 4 Mbytes s-1 Raw Datakrunc

Run Control &DFC

Online farm fibm05

.... fibm10

Offline farm

22 IBM H80 88 CPU 2.7 KHz : total farm power

10 SunOS 40 CPU MonteCarlo DSTs

2 IBM + 2 Sun Users

Reconstruction output 560 GB Job control areas 200 GBRecalled Data from Tape 2200 GB

Magstar 5,500 Cassettes 12 Tape Units

fibm01DB2 Server

2 IBM B80 I/O Servers

2 IBM B80 AFS Servers 1 TByte

Dafne luminosity

(cm-2 s-1)

Maximum reconstructable

luminosity

(pb-1/day)

Data volume

(Gbytes/pb-1)

Raw volume

(GB/pb-1)

Filtered

volume

(GB/pb-1)

Reconstructed volume

(GB/pb-1)

Bhabhas volume

(GB/pb-1)

4 1031 4 390 200 85 35 70

From the first 8 pb-1

Total capacity of the Library inclusive of the Y2001 data set, assuming present running conditions, is 400 pb-1 corresponding to 100 full days of data taking, and if we scratch the filtered sample, is 570 pb-1 corresponding to 177 full days of data taking.

2002 DATA TAKING CONDITIONS

End of 2002 : new Magstar tape drives available Old cassettes written at higher density 50% increase in the Library capacity.

STORAGE FOR DST’s

DST’s are produced immediately after data reconstruction to take advantage of the availability of files on disk

To allow an efficient multi user access to these files they should be kept on disk as much as possible

Present DST volume: 6 GB/pb-1, excluding charged kaons

Estimated DST volume: 25 GB/pb-1, charged kaons included

13 Tbytes by the end of 2002 data taking

~ 3 Tbytes additional disk volume needed (1.6 presently in use)

Disk space : Multi-user access to DSTs (13 Tbytes expected by the end of the year ) requires additional 3 TBytes of disk space

Library : Full by the end of the year. As soon as they will be available on the market, and according to the data taking status we expect to update the tape drivers to increase the total capacity by 50% New storage solutions are under study for the year 2003 data taking.

Computing Power : Less than 50% of the approved total computing power acquired so far. Marginal for any reprocessing campaign, as the 4-full-months needed to reconstruct 180 pb-1 demonstrated.Any new reprocessing campaign will require more .

CONCLUDING REMARKS ON KLOE COMPUTING

LONG TERM PLANS AND PERSPECTIVES

December 2002 : Start long shutdown ~ 6 months

New interaction region : quad triplet doublet(helped a lot in DEAR )

Goal peak luminosity : 5 x 1032

Here comes CP !!

CONCLUSIONS

KLOE has started producing physics results and papers

All of the milestones for 2002 have been (up to now) achieved

We are analyzing year 2001 data for the next round of papers

DANE performances this year look promising for more and better data…