PROSPETTIVE DI FISICA A DA?NE FASE 2

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PROSPETTIVE DI FISICA A DA?NE FASE 2

• Fabio Bossi, LNF
• Padova
• 20/11/03

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KLOE Data taking 2000-2002
Total ? L dt 400 pb?1
2002
Particles collection
2001
7?108 K K? pairs
2000
5?108 KS KL pairs
2?107 ?
2003 run started in October on FINUDA. Goal
deliver 200 pb?1, then switch back to KLOE
for a long run to deliver ?1 fb?1 .
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DAFNE PERSPECTIVES FOR AN UPGRADE
Two option under consideration
? High energy (up to ? 2.4 GeV c.m.)
? Minor modification to the machine
? Physics case baryons form factors, high
precision spectroscopy
? High luminosity ( 1034 cm-2s-1)
? Major modification to the machine and/or
radically new ideas
? Physics case CPT tests, K rare decays,
quantum interferometry, hypernuclear physics
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High Energy
DAFNE 2
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NUCLEON FORM FACTORS IN THE TIME LIKE REGION
Differential x-section
GE, GM complex numbers, need polarization of
final state to measure the relative phase needed
to obtain FPauli and FDirac (i.e. what theorists
calculate!)
GE GM only at threshold, need to know angular
distribution
At large Q2, G(Q2) G(-Q2)
If only valence quarks GM(n) GM(p) / 2
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PROTON FORM FACTOR
pQCD fit
G(Q2) G(-Q2)
factor 2 from naive prediction!
rapid fall just above threshold
A. De Falco
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NEUTRON FORM FACTOR
Data from FENICE only,
74 events ?Ldt 0.4 pb-1
GM(p)/2
GM(n) gt GM(p) !
A. De Falco
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? FORM FACTOR
Only one existing measurement (DM2) based on
4 events _at_ 2.4 GeV
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EVENT YIELDS
?(ee? ? NN) 0.1 ? 1 nb
400 ? 4000 events/day _at_ present luminosity
?(ee? ? ??) 0.1 nb
400 events/day _at_ present luminosity
FINUDA estimates efficiencies ranging between
(5 ? 40) for nucleons (no idea for ?s)
Major limitation of FINUDA present setup is
limited angular acceptance (KLOE has full solid
angle coverage)
FINUDA might measure p polarization!
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MY CONCLUSIONS ON BARYON F.F.

NUCLEON F.F. CAN BE MEASURED WITH UNPRECEDENTED
PRECISION AT D2 AS LONG AS L gt 1031
DISCRIMINATION BETWEEN nn AND ?? EVENTS (B/S
4) BASED ON TIMING MIGHT RESULT VERY DIFFICULT
DUE TO HIGH BUNCH X-ING RATE IN DA?NE
SOME RD WORK HAS TO BE ENCOURAGED ON NEUTRON
EFFICIENCY WITH PRESENT DETECTORS
LAMBDA F.F. MEASUREMENT SHOULD BE PURSUED ? S gt
2.4 GeV
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Muon - Anomaly

• Motivation Determination of Hadronic Vacuum
  Polarization High Precision Test
  of the Standard Model
• Anomalous magnetic moment of the muon am
  (g-2)m
• Running Fine Structure Constant at Z0-mass
  aQED (MZ)

Dirac-Theory (g - 2 ) 0 Quantum
Corrections (g - 2 ) ? 0 due to corrections
of - electromagnetic Interaction - weak
Interaction - strong Interaction (and
maybe NEW PHYSICS ???)
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Status Muon - Anomaly
How to test the Standard Model?
Compare experimental Value with Theory -
Prediction for Muon-Anomaly
New Data Input from
a) CMD-2 (Novosibirsk) in p p-
Channel 0.6 Precision lt 1 GeV
reanalysis of their data publ.
08/03 b) t-Data from ALEPH,
OPAL, CLEO
Experiment E821 (BNL 02) dam(exp.) 0.7 ppm
THEORY 08 2003

THEORY 03
Theory Evaluation using only e e- - Data 2 s -
Deviation

Theory Evaluation using only t Data Agreement
with Exp.
PRESENT KLOE DATA CONFIRM CMD-2
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A. Denig
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A. Denig (Alghero Workshop)
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WHAT CAN BE USED FROM DAFNE

• DAFNE2 can exploit DAFNE hardware
• vacuum chamber
• all quads and sexts
• RF cavity
• Feedback, vacuum system...
• But needs new
• stronger bending dipoles
• 4 SC quads in IR2

C. Biscari
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Dipole Section
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Magnetisation curve
1100 MeV
1050 MeV
1020 MeV
510 MeV
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Injection - Full Energy
Linac upgrade up to 1.1 GeV injecting directly
in rings transfer lines septa
DOUBLING THE DAFNE-LINAC ENERGY IS FEASIBLE AT
MODERATE COST (6 MEuros)
C. Biscari
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or Injection - Ramping

• there is no problem implementing energy ramping
  for DAFNE II
• Inject and ramp time ltlt beam lifetime at 1.1GeV
• All of the PS can be reused
• It simply requires
• High Level Software development
• careful hardware configuration.

C. Biscari
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Conclusions of High E option
Energy upgrade to 1.02 GeV/beam straightforward
and at moderate cost Exploit most of existing
hardware Preliminary design for dipoles with
some questions about - maximum achievable field
(-gt Emax 1.1 GeV) - current
dependence of field quality Parameters of
superconducting IR quadrupoles are well
within the range of existing designs
C. Biscari
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High Luminosity
DA?NE x 100
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Ideas for Luminosity increase
Some will be tested in near future
Others

• collisions with neutralized beams
• (four beams) feedback system
• ring against linac
• Monochromators
• Collisions with large crossing angle
• Ecm 2Ebeamcos(qc/2),
• e.g. qc/2 60,Ebeam1GeV

• Crab cavities (KEK-B)
• Collisions with round beams (VEPP2000)
• Negative aC (KEK-B, DAFNE)

C. Biscari
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A novel approach large crossing angle
If we want to collide at the F-pole, we could
increase the ring Energy by greatly increasing
the crossing angle 2a, such as Ecm
2Ebeamcos(a)
detector
Ecm 1 GeV
E 1 GeV
E - 1 GeV
For example a60 corresponds to Ebeam1GeV
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Main guidelines for the designL 10 34 at F
energy
Double ring Multibunch operation

• Powerful damping
• Negative momentum compaction
• Very short bunch at IP

C. Biscari
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Luminosity 1034set of consistent parameters
new
challenges
C. Biscari
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ZOOM OF THE RINGS SECTION
QUADRUPOLES
SEXTUPOLES
1m
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KLOE AT DA?NE

1. Nature of scalar mesons
2. KS semileptonic decay
3. KS decay into 2?

Yesterday (20 pb-1)

1. More a), b), c)
2. Charge asymmetry in KS semileptonic
3. Main and medium-rare decays of KL and K?
4. Vus measurement
5. Hadronic cross section
6. Limits on KS ? 3?

Today (400 pb-1)

1. More 2), 6) and part of 3)
2. Quantum interferometry

Tomorrow (2000 pb-1)
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Kaons _at_ DA?NE
The ? decay at rest provides monochromatic and
pure beams of Kaons

• K rare decays
• Absolute branching ratios
• K lifetimes

KK- 1.5? 106 /pb-1 p 120 MeV/c KLKS
106 /pb-1 p 110 MeV/c
The variety of K decay channels and the
possibility for a complete closure of the
kinematics allow the selection of many samples
for measuring the efficiencies directly from data.

• The ? decays at rest allow us to select
  monochromatic (p 110 MeV/c) pure beams of
  Kaons
• K rare decays.
• Absolute branching ratios
• K life times
• The variety of K decay channels and the
  possibility for a complete closure of the
  kinematics allow the selection of many samples
  for measuring the efficiencies directly from
  data.

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Tagged KL and KS beams
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KS SEMILEPTONIC DECAYS
170 pb-1
BR(KS ? ?e?) (6.8 ?0.15) 10-4
ASL (19 ?18) 10-3
KL ?B/B 0.7 ?AL 0.007
Preliminary result using all data to be
presented at next SC
?B/B 1.6 ?AS 1.3
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KS SEMILEPTONIC DECAYS AND THE ?S ?Q RULE
The relevant parameter is
lte??? Hwk K0 gt
Re (x)
10?6 S.M.
lte??? Hwk K0 gt
?S
1 4 Re(x)

Present Uncertainties
?L
8 10?3
BR(KS ? ?e?) ?L

BR(KL ? ?e?) ?S
1 10?3
7 10?3
KLOE can improve a lot on this with
present data
10 fb?1 would give 2 10?3 on BR(KS )
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KS SEMILEPTONIC DECAYS AND TESTS OF CPT
In the SM bd0 if CPT holds Suppressed by
DSDQ rule (cd0)
AS 2(Re eK Re dK Re b/a - Re d/a) AL
2(Re eK - Re dK Re b/a Re d/a)
4 Re ? AS - AL
CPT
CP
Test if AS consistent with 2 Re ?
2 fb-1
Next run
Measurement of AS to 30
20 fb-1
DA?NE 2
100 fb-1
Competitive measurement of Re ?
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The numbers above assume present detection
efficiency for signal ?TOT 6
One can recover some acceptance by the use of a
vertex detector and a lower magnetic field
One can improve e/? separation increasing
calorimeter granularity
RD work needed !
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KS ? 3?0
This CP violating decay has a predicted B.R.
of 1.9 10?9 with a relative error of 2.4
KLOE will present at next SC its preliminary
limit with present statistics (O(10?7) )
efficiency after all fiducial cuts 10
NOBS 20 events in 100 fb?1
At this level some more work on background
rejection needed!
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Kaon interferometry what can be measured
A . Di Domenico
Double differential time distribution
where t1(t2) is the time of one (the other) kaon
decay into f1 (f2) final state and
characteristic interference term at a f-factory
gt interferometry
fi pp-, p0p0, pln, pp-p0, 3p0, pp-g ..etc
Integrating in (t1t2) we get the time difference
(Dtt1-t2) distribution (1-dim plot)
From these distributions for various final states
fi we can measure the following quantities
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Kaon interferometry main observables
A . Di Domenico
mode
measured quantity
parameters
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KLOE preliminary
340 pb?1
Dm (5.64 ? 0.37) ? 1011 ? s-1 PDG 02 (5.301 ?
0.016) ? 1011 ? s-1
FIRST EXAMPLE OF QUANTUM INTERFERENCE WITH KAONS
At a new f-factory with 100 fb-1 dDm
0.018 ? 10-11 ? s-1
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KLOE has just started attacking its main
original program i.e. measuring all the
parameters of the neutral K system ( among which
Re (?/?) ), for which it were originally
estimated to be needed 5?10 fb?1
With present efficiencies one may think to need
20?50 fb?1 i.e. DA?NE 2
Again, KLOE experience (phase 1) can be a
guidance to possible hardware interventions on
the detector to improve its performace (better
QCAL?, vertex detector?)
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AN INTERLUDE KL ? 2?
G(KL ? gg) / G(KL ? p0p0p0)
NA48 e KLOE have measured R
R(2.790.02stat0.02syst)?10-3
(370 pb?1 )
KLOE
R(2.810.01stat0.02syst)?10-3
NA48
The value of BR(KL ? 2?) is presently limited
by BR(KL ? p0p0p0 ) that is know to 1.3
KLOE will measure this BR to ltlt 1 with present
data
A new measurement of R to a better precision
(both statistical and systematical) will soon be
needed
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G. Isidori
Theoretical error lt 10
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KL ??0?? at a ? factory?

• Kaons are tagged
• Kaons 4-momentum is known (reconstruction
  of decay kinematics allowed)
• Beam free of neutral baryons backg.

A ?-factory is naturally suited for this
search since
Production rate 106 KS-KL pairs / pb-1
1 year _at_ 1035 cm-2s-1 1012 KL produced
observed decays 30 ? ?tot / year (SM)
must be ?tot ?? 10
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but still remember
G. Isidori, Alghero Workshop
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HYPERNUCLEAR SPECTROSCOPY
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OPEN QUESTIONS
A. Feliciello
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FINUDA IS COMING!
A. Feliciello
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ONE STEP BEYOND ? SPECTROSCOPY
NEED HIGH LUMINOSITY DUE TO LOW EVENT RATES
(AND LOW DETECTOR EFFICIENCIES)
A. Feliciello
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FINUDA WITH GERMANIUM DETECTOR
SLIGHTLY REDUCED DETECTOR ACCEPTANCE
A. Feliciello
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PRODUCTION OF NEUTRON RICH HYPERNUCLEI
V. Paticchio
Typical counting rate with FINUDA _at_ 1034 130
ev/h
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DAFNE status and outlook

• Adiabatic changes on DAFNE approaching to an
  end.
• DAFNE performances expected to reach the
  original design goals (L 5 10 32), within the
  next 2 years.
• 3- 4 years of physics program fully booked with
  current (or slightly upgraded) detectors.
• After that, only radical changes possible

S. Bertolucci, closing Alghero workshop