Diapositiva 1

1
Report from
A. Passeri

• Expression of Interest
• Physics goals
• Detector developments
• Collaboration setup

2
http//www.lnf.infn.it/lnfadmin/direzione/KLOE2-Lo
I.pdf
72 physicists
12 institutions
3
Expression of Interest

• Vast physics program both at the f peak and in
  the range 1lt ?s lt 2.5 GeV
• Require ?Ldt ? 50 fb-1 in a 3?4 years running
  period at the f peak
• (i.e. 5 x 1010 KSKL events and 7.5 x1010
  KK- events),
• in order to reach significant sensitivities for
  the study of neutral kaon
• interferometry, KS rare decays, lepton
  universality test and h, h program.
• Require to run also at higher energies to
  accomplish the multihadronic cross
• section measurement and the gg program. Energy
  scan highly recommended,
• with average L1032cm-2s-1 .
• Expect to start experimental program in 2011
• Plan to use the KLOE detector with some
  important upgrades

4
Physics goals at the f peak
Kaon physics KS rare decays ? pen, pmn, 3p0,
pp-p0, p0ll-
Study neutral kaon interference search for CPT
violation,
quantum decoherence, EPR phenomena, test Bells
inequality.
Improve, where possible, all KLOE BR measurements
? Vus Search for
LFV effects in Ke2 decays
h, h physics extensive cPT tests, very
sensitive to hadron structure,
light quark masses and couplings
h(h)?3p , h?hpp
Radiative decays h(h)?gg, pp-g, pp-ee- ,
h?p0gg C,CP
violation h?pp, ggg, p0p0g, p0ll- h?ll-h

• Light scalars Investigate the nature of the
  established scalars f0(980), a0(980)
• measure their
  s-quark couplings via f?(f0a0)g?KKg
• Search for the
  controversial lighter scalars s(600) and K(800)
• via gg process.

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Physics goals in the region 1?s 2.5 GeV
Hadronic cross section Provide R measurement
for am and aem determination.
Perform an accurate energy scan. Improve
by a factor of 10 the
present BABAR exclusive cross section
measurements. Afford
the only inclusive shad measurement since 80s.
Vector meson spectroscopy
study r, ?, f recurrencies and their place
in hadron multiplets.
Understand the nature of r(1900) (glueball?).
gg physics Study h, f0, a0 production and
their gg width (related to the
quark structure of the hadron).
The program is wide and spread over many topics.
All together they offer a rich experimental
field.
In the following I will briefly discuss mainly
the kaon part. The rest will be addressed in
C.Binis talk.
6
The KLOE heritage Vus
CKM matrix unitarity test can be refined by 1
order of magnitude.
Vud2 Vus2 Vub2 Vud2 Vus2 ? 1
D 0.9997 0.0013
Presently
Vud from superallowed Fermi transition Vus
dominated by KLOE measurements of K semileptonic
decays
Precision limited by hadronic corrections
KLOE does also extract Vus from
?(K????(?))/?(?????(?)) ratio. Precision
limited by the theoretical uncertainity on the
fK/f? evaluation.
Recent progress in lattice QCD seems to open the
possibility of lowering the theoretical
uncertainty to 0.1
Considering the actual KLOE performances and
assuming that systematics will scale with
statistics, a factor of 100 more statistics is
needed to match the theoretical precision, i.e.
40 fb-1
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Lepton universality test
In extended SUSY models large contributions to
Ke2 decay are expected from LFV terms
First studies are going on in KLOE need to fully
exploit calorimeter for e/m separation. A
reasonable guess, based on present detector, is
that 50 fb-1 would push relative error around
0.5. But efficiency could improve dramatically
with an increased calo granularity and
with a better inner tracking stage.
8
CPT violation tests
Violation expected in QG models. No obvious scale
predictions.

• The f-factory environment provides a unique
  opportunity to test the
• existence of such effect, in 3 different ways
• The comparison of KS and KL semileptonic decay
  charge asymmetries
• Via the Bell-Steinberger relation
• By studying the quantum interference between
  entangled kaon pairs
• produced in f decays. This is also allow to
  perform tests of quantum
• coherence, EPR paradox and Bells
  inequality.

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CPTV I KS semileptonic decay asymmetry
AS ? AL ? 0 implies CPT
AS 2(Re ?K ?Re ?K ?Re b/a ?Re d/a)
AL 2(Re ?K ?Re ?K ?Re b/a ?Re d/a)
Present results
AL
KTeV-02
AS
KLOE 400pb-1
With a 50 fb-1 sample s(AS)10-3 But
acceptance can be increased up to a
factor of 2 just by lowering the B field
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CPTV II Bell-Steinberger relation
From unitarity conditions
Im(d) ? 0 can be only due to CPTV, unitarity
violation or exotic states.
After KLOE measurement of BR(KS?3p0) Im(d)
(1.2 3.0) 10-5
The next limiting inputs to B.S. are h- and h00
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CPTV III Quantum interference

• interference pattern I(Dt) for different final
• states f1,f2 give access to different
  parameters
• a good vtx resolution is required s(Dt)lttS
• ? quest for an improvement of inner tracking!
• several QG models predict CPTV terms in the
• interference time evolution

I(Dt)
f1,f2 pln
large Dt
Semileptonic decays give access to dK
small Dt
Dt/tS
12

• Generic quantum decoherence (which can also
  signal CPTV) is introduced via
• a parameter z . KLOE already measured
• 50fb-1 more would reduce error by 10.

• In the EHNS model the interference pattern
  contains 3 CPTV parameters
• a, b, g o (MK2/MPlanck) 10-20 GeV
  KLOE measurements still worse than CPLEAR

KLOE2 figure of merit constant line is CPLEAR
VDET means svtxtS/4

• in BMP model CPTV modifies the concept
• of antiparticle and KSKL state deviates from
• Bose statistics via a parameter ?

Preliminary KLOE measurement is already at
10-4 level. KLOE2 can go up to 10-5
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Rare KS decays
BR(KS?pen) is still the limiting factor in the
test of DSDQ rule by 3
error reduction on Re(x) provided systematics
scales with stat BR(KS?pmn) same as the above,
but more difficult. Expected error at
0.4. BR(KS?gg) test of cPT at o(p4). NA48
measurement 30 apart from calculations.
Current error is 2.7. KLOE2 can go
below 1 BR(KS?pp-p0) another test of cPT,
predictions around 10-7. KLOE2 expected
precision around 15. Would benefit
from B field reduction. BR(KS?3p0) CP and CPT
test. Expected at 10-9, present limit at 10-7.
KLOE2 can aim to observe
the signal. BR(KS?p0ll-) very important to
evaluate the CPV via mixing contribution to the
rare analogous decay of KL.
Present NA48 measurement based on
76 events. With conservative efficiency
estimate KLOE2 expects to
perform a measurement at the same level.
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R measurement and energy scan
Hadronic contribution to aem(MZ) is very
important in the region 1lt?slt2.5 GeV If not
measured at few level is going to be the
limiting factor for future precision
calculation (linear collider physics). B
factories are already doing it !
Radiative return with 2 fb-1 at 2.4 GeV
Energy scan 20 pb-1 per point
BABAR now
BABAR full stat
KLOE2
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The KLOE detector
EmC
DC
Lead/scintillating fiber 4880 PMTs 98 coverage
of solid angle
4 m diameter 3.75 m length 90 helium, 10
isobutane 12582/52140 sense/total
wires All-stereo geometry
?E/E 5.7 / ?E(GeV) ? t 54 ps / ?E(GeV) ? 50
ps (finite bunch-length contribution subtracted)
?p/p 0.4 (tracks with ? gt 45) ??? 150 ?m ?z
2 mm
solenoidal 0.5 T magnetic field
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The KLOE concept
Excellent e/? separation based on t.o.f.
Good ?0 reconstruction capabilities
Full kinematical reconstruction of events
The focus in KLOE design was mainly on efficiency
for long-lived particles (K ,KL), but the
detector provides as well acceptable efficiency
and resolution for prompt particles.
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KLOE detector weaknesses for DAFNE2 physics

• KLOE ( K LONG Experiment ) was not fully
  optimized to detect low momentum tracks coming
  from IP (KS, h? decay products)
• Tracking starts at 25 cm from IP both tracking
  and vertex efficiency affected
• Calorimeter readout granularity does not prevent
  cluster merging and is not sufficient for a a
  shower-shape pid.
• at f peak, gg physics impossible without small
  angle e tagger
• Physics and background rate could be an issue for
  DAQ and trigger

Proposed upgrades

• Lower B field from 0.5 T to 0.3 T (at least at
  f peak)
• Add an inner tracker at 10lt R lt 25 cm
• refine calorimeter readout granularity
• Small Angle Tagger for gg events placed
  downstream
• Trigger and DAQ upgrades

18
B field from 5 ? 3 KGauss ?

• Increase acceptance for low momentum tracks
• coming from I.P.
• Reduction of spiralizing tracks ? less tails in
  
• momentum resolution

KS?pp-p0
Simulated Km2 events
Drawback sp worsening for tracks at higher pT
(gt150 MeV/c)

• However other effects, depending on the
• channel, may partially compensate
• According to simulation 40 B field
• reduction produce only a 15 sp increase
• in Km2 events

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Inner tracker requirements

• It must start at R 20 tS , to avoid spoiling
  the KSKL interference path
• To maximize acceptance it must extend up to q30o
  
• It must be able to provide independent tracking,
  i.e. must measure at least
• 4 or 5 3D-spatial points.
• It must be very light, not to spoil sP a total
  material 1 X0 is acceptable
• hit resolution lS is only upper limit from
  physics but for independent
• tracking we must ensure that contribution to
  sP is better than M.S.
• ? shit 200 mm is enough for 10 cm track
  length
• it must sustain a very high rate extrapolation
  from KLOE machine
• background monitors yields a pessimistic
  figure od 30?40 hits /plane/ms

• easy using straw tubes layers. Very light.
• Electronics and mechanics
  standard.
• challenging cylindrical GEM. Expertise exists
  at LNF,
• but detector shape is totally new.

considered solutions
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Courtesy of G.Bencivenni
Principle of operation of a GEM detector

• The GEM (Gas Electron Multiplier) (F.Sauli, NIM
  A386 (1997) 531) is a thin (50 mm) metal coated
  kapton foil, perforated by a high density of
  holes (70 mm diameter, pitch of 140 mm) ?
  standard photo-lithographic technology.
• By applying 400-500 V between the two copper
  sides, an electric field as high as 100 kV/cm is
  produced into the holes which act as
  multiplication channels for electrons produced in
  the gas by a ionizing particle.
• Gains up to 1000 can be easily reached with a
  single GEM foil. Higher gains (and/or safer
  working conditions) are usually obtained by
  cascading two or three GEM foils.

LHCb GEM configuration
A Triple-GEM detector is built by inserting three
GEM foils between two planar electrodes, which
act as the cathode and the anode.
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LNF Detector Development Group F.Anulli,
G.Bencivenni, D.Domenici, G.Felici, F.Murtas
Cylindrical GEM development

• The basic cylindrical structure can be realized
  with the straw-tube technology
• The cylinder is obtained winding a
  parallelogram-shaped kapton foil. A helicoidal
• joint line (3 mm wide) is left
• Two consecutive cylindrical electrodes have
  opposite
• helicity in order to reduce the overlap of
  joint lines
• to only one point (3x3 mm2).

• A detector layer is composed by five concentric
  cylindrical structures
• the cathode, the 3 GEM foils, the readout anode.
• Anode and GEM3-down (where only electron fast
  signals are
• present) are equipped with U-V strip readout
  for stereo view.
• Strip pitch is 400 mm.
• The cylindrical electrodes are glued at the ends
  on circular
• frames, by which the detector can be hung to
  the beam
• pipe, avoiding any internal support frame

First prototype for mechanical test successfully
produced
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GEM vs KLOE2 requirements

• Cylindrical GEM can be assembled in 5 detector
  layers at 10ltRlt25 cm
• providing 3D spatial measurements for a total
  surface of 33000 cm2 and
• 27000 readout channels (for a 400 mm pitch).
• Hit resolution around 170 mm.
• Thickness grand total for 5 layers between
  0.92 and 1.57 X0
• (depending on copper coat thickness).
• Sustainable rate up to 50 MHz/cm2 (measured in
  planar GEM).
• Time resolution 4?5 ns.

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Calorimeter readout granularity why refine it ?
Avoid cluster splitting.
and merging
and on top of that..
Improve e/m/p separation via cluster
shape variables
6 g events
After kinematic fit c2 cut
Started a detailed calorimeter simulation based
on FLUKA mc

• lead foils, including 5 Bi
• glue Bicron BC-600ML, in all components
• individual fibers
• polystirene core PMMA cladding

24
Standard KLOE calorimeter behaviour well
reproduced for photons
sE/E
sz
Energy and spatial resolutions compared to
measured ones
FLUKA
..
Data resol
Eg (MeV)
Eg (MeV)
Cluster depth and rms compared to pp- g events
centroid rms (cm)
centroid depth (cm)
Eg (MeV)
Eg (MeV)
25
Granularity tests with 1000 events with two 200
MeV electrons
preliminary
4.4x4.4cm2
Digitized cells KLOE granularity
Generated energy release
Energy
1x1cm2
2x2cm2
KLOE granularity x 16
KLOE granularity x 4
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Granularity tests with 1000 events with two 200
MeV muons
Digitized cells KLOE granularity
4.4x4.4cm2
preliminary
Generated energy release
Energy
1x1cm2
2x2cm2
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Calorimeter granularity refinement how to
implement it ?

• Still a lot of work to do with simulation and
  comparison to KLOE data
• Light readout could be performed with
  multi-anode PM tubes, like
• Hamamatsu R7600-00M4 or 00M16, having very
  good risetime and
• QE similar to present PMs. Sample of such
  devices already purchased,
• to be tested very soon.
• Light guides should be replaced with smaller
  ones not an easy job !
• Prototyping and testing is mandatory
• Granularity could be refined only on first 1 or
  2 planes, and eventually only
• in the barrel region.
• FEE should be redesigned for the new cells,
  while old cells FEE boards can
• be used as spares for the remaining ones.

28
Trigger considerations
Simple rate scaling shows that KLOE2 Must work
well above 10 KHz total rate, depending on
machine bckg

• DAFNE
  DANAE
• ? events 300 Hz
  2500 Hz
• Good Bhabhas 600 Hz 5000 Hz
• Residual cosmics 600 Hz 600 Hz
• Machine backgr. 500 Hz ?
  

• If machine bckg does not increase dramatically,
  present minimum bias
• trigger strategy (2 hw lvls 1 sw) can be
  mantained, with Bhabha prescaling ON.
• The 3rd level filter must become more selective,
  to minimize the fraction of
• non-interesting events on tape.
• Most of the present trigger custom boards (11
  diferent types) need to be
• designed, for lack of spares and components
  obsolescence
• DC trigger need to be reconsidered actual
  thresholds are not easily under
• control, and may change trigger conditions
  unexpectedly.
• A gg physics trigger must be included
• At high energy multiplicity will increase
  trigger should be even more efficient.
• However threshold tuning will be necessary.

29
DAQ at KLOE2

• KLOE DAQ was designed to sustain 50 Mbyte/s and
  was tested up to
• 80 Mbyte/s , divided between 10 similar
  acquisition chains.
• Its architecture can be kept, provided we
  overcome 3 bottlenecks
• VME block transfer from 2nd lvl concentrator to
  CPU, limited at 20 Mbyte/s
• ? VME64x protocol, together with the new
  2eSST block transfer (Double-edge
• Source Syncronous Block Transfer) can
  transmit up to 320 Mbyte/s !
• FDDI data transfer from 2nd lvl CPUs to
  onlinefarm, limited at 12.5 Mbyte/s
• ? can be replaced by Gigabit Ethernet
• 2nd lvl CPUs (old DEC) data framing, limited
  around 8 Mbyte/s
• ? Motorola MVME6100 implements both VME64
  and Gigabit Ethernet

A tester board has been realized to test the full
environment. MVME6100 running Linux with a
custom vme driver and the KLOE online sw.
Measured sustained rate is 180 Mbyte/s
Aloisio,Branchini,Cevenini,Izzo,Loffredo,Lomoro
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Setup of the collaboration
For the moment 72 physicists in
12 institutions Out of which 44 are
italians 4 are italians
41 are also in KLOE 7
are also in KLOE Doors are
open to newcomers who share the same
physics program

• By end of june a KLOE2 full meeting is planned
  to
• start giving the collaboration a governing
  structure
• define together the next milestones and start
  sharing working items

31
Conclusions
A sizeable group of experimental physicists has
expresses interest in a wide physics program to
be performed at the next Frascati ee- collider,
both at the f peak and at higher energy
We plan to use the KLOE detector with some
important upgrades, for which we have already
started developments.
32
Spare Slides
33
Vus from KLOE results (BRs and tL)
KL e3 KL m3 KS e3 K ? e3 K ? m3
BR 0.4007(15) 0.2698(15) 7.046(91)10-4 0.05047(46) 0.03310(40)
t 50.84(23) ns 50.84(23) ns 89.58(6) ps 12.384(24) ns 12.384(24) ns
c2/dof 1.9/4
34
Vus and Unitarity

• tL 50.99(20) ns,
• average KLOE-PDG
• Including all new measurements
• for semileptonic kaon decays
• (KTeV, NA48, E865, and KLOE)

ltVusf(0)gtWORLD AV. 0.2164(4)
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The Vus- Vud plane
unitarity
Fit results, P(c2) 0.66 Vus 0.2246 ?
0.0016 Vud 0.97377 ? 0.00027 Fit result
assuming unitarity, P(c2) 0.23 Vus 0.2264
? 0.0009
36
Ke2 Momentum distribution
Red MC blu ke2 black data
Lab momentum

• We use as starting point a sample of 80000 Ke2
  corresponding to 2fb statistic. (IBSD)
• MC 2005 was used with the new charged kaon noise
  inserted
• The K decay must be reconstructed with vertex
  in FV
• The electron momentun ranges in 200-300 MeV/c
  region. Same as the muons from K?2

SD
Mev/c
37
Multiple scattering vs thickness
Comparison between MS induced by 2 reference
value of silicon thickness (1mm and 1.5 mm) wrt a
KLOE-like 700??m of carbon fiber. A thickness
larger than 1mm of silicon equivalent ( 1 of
X0) can be a limiting factor for the momentum
mesurement of low momentum particle coming from
IP . Problem can also be given by the conversion
of photons from machine
38
DATA CONCENTRATOR
Level 2
Level 1
16 DAQ FEE boards
Trigger
V I C
AUX bus
C P U
TSFIO
C-bus
Trigger lines
VIC
VME bus
VME bus
Vic bus
R O C K M
V I C

F D D I
C P U
V I C
Trigger lines
DAQ Chain
AUX bus
39
In KLOE the link and the switch between fee and
farm is based on FDDI IT MUST BE CHANGED
40
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