Camilla Di donato

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Hadron Physics at KLOE and KLOE-2

• Camilla Di donato
• Sez. infn napoli
• On behalf of kloe and kloe-2 collaborations

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Outline

• Hadron Physics _at_ KLOE/2
• U-boson Search ???ee-/?U
• Light Meson Spectroscopy ? and ?? physics
• Other KLOE/2 results not discussed here
• PS Transition FF
• ?? Physics
• ?/f0(600)
• Study of ?(S/PS ???)
• Pion FF from ee-? ???/???

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KLOE and KLOE-2 _at_ DAFNE
e.m. calorimeter resolution
d.c. performances
DAFNE ee- collider _at_ ?s ?1020 MeV
?peak?3.1 ?b
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U-Boson Search

• ???U

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Low Energy Dark Forces
Several unexpected astrophysical observations
(PAMELA, ATIC, INTEGRAL, DAMA/LIBRA, CoGent...)
could be explained with the existence of a hidden
gauge sector weakly coupled with SM through a
mixing mechanism of a new GAUGE BOSON (U, A?, V)
with the photon
Arkani-Hamed et al. PRD79 015014 (2009) Essig
et al. PRD80 015003 (2009)

• U mass range 1 MeV few GeV
• Coupling constant of electric charge to U ? ?
  10-3
• U production/decay through photon mixing

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Search for U boson _at_ KLOE

• Meson Decays ???U, ??U?, ?0? U?
• Peculiar of a light meson factory
• ee- collisions ee-? U?
• x-sec ? 1/s 100 times higher at DAFNE w.r.t.
  b-factories/ compensate lower luminosity
• h?-strahlung ee-? U ? Uh?
• If the hidden simmetry is spontaneously broken by
  a Higgs-like mechanism, the existence of at least
  one other scalar particle , can be postulated ?
  h?

Meson can decay to a U boson with
for
Irreducible background ? Dalitz decay
???????ll- , (? 0.7 nb)
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??? e e- , with ????-?0
PLB706 (2012) 251-255
L 1.5 fb-1
BR(???ee-)1.15 ? 10-4 produced events ? 106
???ee-
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??? e e- , with ????-?0
PLB706 (2012) 251-255

• We have ?14000 candidates ???ee- with ??? ?-
  ?0
• Very small residual contamination from ????
• MC Mee shape from VMD with FF slope from SND (213
  events) PLB504 (2001) 275
• Background extracted directly from data

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Fit to Mee Shape
Using decay parametrization from Landsberg85 and
F(q2) approx. from Achasov, Kozhevnikov, Sov.
J. Nucl. Phys. 55 (1992) 449
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Exclusion plot for ????
PLB706 (2012) 251-255
Evaluation of ???? ? ? UL takes into account

• Kinematic factors Reece-Wang, JHEP0907051
  (200)
• Opening of U???- threshold

PLB706 (2012)
???? ? 2 ? 10-5 _at_ 90 C.L. for 50 lt MU lt 420 MeV
PRL107 (2011)
PRL106 (2011)
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??? e e- , with ?? ??/?0?0?0
Preliminary studies on ???? and ???0?0?0 decay
channels produce encouraging results
U.L. can be improved by a factor 2
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Light Meson spectroscopy

• ????-?
• decay

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Light Mesons ????- ?

• Box Anomaly ????????????are expected to get
  contribution from anomaly, Wess Zumino Witten
  term in ChPT Lagrangian
• According to Effective Theory (HLS Benayoun,
  Eur. Phys. J. C31 (2003) 525), they could be
  described by VMD a direct term

• Studies of final state interaction by unitarized
  extensions
• Picciotto, Phys. Rev. D45 (1992) 1569
• Benayoun, Eur. Phys. J. C31 (2003) 525
• Holstein, Phys. Scripta, T99 (2002) 55
• Borasoy, Nissler, Nucl. Phys. A740 (2004) 362

?
?
?-

?/??
?
VMD
CT

• Model independent method based on ChPT and
  dispersive analysis do not fix relative strength
  between tree level contribution and resonance
  contribution
• (Stollenwerk, Hanhart, Kupsc, Mei?ner and Wirzba
  PLB707 (2012) 184-190)

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??????- ??????????0 ?

• Theory HLS-Model
• ?(???????)w (56.3?1.7) eV
• ?(???????)wo (100.9?2.8) eV
• ?(???????) (60?4) eV PDG provide strong
  evidence in favour of BOX Anomaly

This analysis L 558 pb-1 ? 2?107 ?
mesons (4.6 ???????)
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????, ????- ?

• ? 2 ? clusters tcl-lcl/clt5?
• 2 Tracks closest to IP
• 1 ? clusters E? gt250 MeV
• Two body ? decays constrain E??
• Kinematic from ? decays constrain ??
• Main background ????-?0
• BKG feature in the ?0 rest frame ?????? are back
  to back (???????? lt 165)
• TOF to reject ee- background

Events/4 MeV
M???

• Signal in M ??-? window (539.5554.5) MeV

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????- ?
Data sample L 558 pb-1 N???????g 204
950 ?(21.31?0.04) B/S10 Signal counting
from fit to E-P
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Normalization Sample ????- ?0

• ????????
• L 558 pb-1
• N????????? 1190?103
• ?(22.77?0.02)
• B/S0.65
• ??ee-??????
• 41.8 ?0.2 nb

BR(????????) (22.41 ?0.03 ?0.35) (systematics
include 0.5 (lumy)?1(x-sec.)? 1 (evcl)?
0,43 (cut analysis) 1.56 )
PDG10BR(????????) (22.74 ?0.28)
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??????- ??????????0 ?

• Measurement has been performed on L558pb-1
• N???????204950 and N???????? 1190000
• Systematics at level of 1.5

• Theory HLS-Model
• ?(???????)w (56.3?1.7) eV
• ?(???????)wo (100.9?2.8) eV
• ?(???????) (60?4) eV PDG

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????- ?
d?/dM??

• Fit with Model independent method based on ChPT
  and dispersive analysis (Stollenwerk, Hanhart,
  Kupsc, Mei?ner and Wirzba PLB707 (2012) 184-190)

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Dipion Invariant Mass
PLB707 (2012)
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Dipion Invariant Mass
NTeo (taking into account efficiency and
smearing)
Ndata
PRELIMINARY
WASA Coll. PLB707 (2012) 243-249
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DAFNE-Upgrade

• DA?NE upgrade -New interaction scheme
• large beam crossing angle sextupoles for crab
  waist
• Luminosity increase factor 3 ? Ldt ? 1
  pb-1/hour

New scheme
Old scheme
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KLOE Upgrade
Inner Tracker 4 layers of cylindrical triple GEM
Minimal detector upgrade for first KLOE-2 run (5
fb-1 in 1 year) taggers to detect momentum of
leptons in ee-?ee-gg?ee-X
Q-CALT/C-CALT Increase acceptance for ?s from
IP (21?10)
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Conclusions

• High statistic samples of light mesons produced
  _at_KLOE allowed to perform precision measurement
  and to look for very rare decays
• Analysis on full KLOE data set
• f ? hU, h ? pp-p0 PLB706 (2012) 251-255
• h ? pp-g Preliminary in arXiv 1107.5733
  hep-ex
• gg ? h/gg ? p0p0 arXiv 1107.3782 hep-ex
• ? ee- taggers in KLOE-2
• pp-g/mm-g
• New data taking_at_KLOE-2 in 2012 not stable
  running yet

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SPARE
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??? e e- , with ????-?0
PLB706 (2012) 251-255
BR(???ee-)1.15 ? 10-4 produced events ? ?106
???ee-
?? Ks KL
? peak
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??? e e- , with ????-?0
PLB706 (2012) 251-255

• We have ?14000 candidates ???ee- with ??? ?-
  ?0
• Very small residual contamination from ????
• MC Mee shape from VMD with FF slope from SND (213
  events) PLB504 (2001) 275
• Background extracted directly from data

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?? Physics
Weizsäcker-Williams approx, q?2 ltlt W2
Tagger is essential to reduce bckg from f and to
close kinematics ? KLOE-2
Lint 1 fb-1
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?? Fusion
_at_KLOE without tagger
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?? Fusion
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?? Fusion
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?? Fusion
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?? Fusion
_at_KLOE without tagger
PRELIMINARY

• 240 pb-1 _at_ ?s 1 GeV
• 8090 events after selections
• Bkg normalized using x-sections

KSKL
?p0
f0?