1. Hadron Physics at KLOE and KLOE-2
Camilla Di donato
Sez. infn napoli
On behalf of kloe and kloe-2 collaborations

2. Outline Hadron Physics @ KLOE/2 U-boson Search: e+e-/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 e+e- /
C. Di Donato - Rencontres de Moriond QCD

3. KLOE and KLOE-2 @ DAFNE e.m. calorimeter resolution d.c. performances
DAFNE: e+e- collider
@ s 1020 MeV ;
peak3.1 b
C. Di Donato - Rencontres de Moriond QCD

4. U-Boson Search
U
C. Di Donato - Rencontres de Moriond QCD

5. [Arkani-Hamed et al. PRD79 015014 (2009)]
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. PRD (2009)]
[Essig et al. PRD (2009)]
U mass range: 1 MeV – few GeV
Coupling constant of electric charge to U:   10-3
U production/decay through photon mixing
C. Di Donato - Rencontres de Moriond QCD

6. Search for U boson @ KLOE
Meson Decays: U, U, 0 U …
Peculiar of a light meson factory
e+e- collisions: e+e- U
x-sec  1/s : 100 times higher at DAFNE w.r.t. b-factories/ compensate lower luminosity
h-strahlung: e+e- 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 l+l- , ( = 0.7 nb)
C. Di Donato - Rencontres de Moriond QCD

7.  e+ e- , with +-0 L = 1.5 fb-1 BR(e+e-)=1.15  10-4 :
PLB706 (2012)
 e+ e- , with +-0
L = 1.5 fb-1
BR(e+e-)=1.15  10-4 :
produced events
 106 e+e-
C. Di Donato - Rencontres de Moriond QCD

8. PLB706 (2012)
 e+ e- , with +-0
We have 14000 candidates: e+e- 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
C. Di Donato - Rencontres de Moriond QCD

9. Fit to Mee Shape Using decay parametrization
from Landsberg85 and F(q2)
approx. from Achasov,
Kozhevnikov, Sov. J. Nucl.
Phys. 55 (1992) 449
C. Di Donato - Rencontres de Moriond QCD

10. Exclusion plot for 
PLB706 (2012)
Exclusion plot for 
Evaluation of   
UL takes into account:
Kinematic factors [Reece-Wang, JHEP0907:051 (200)]
Opening of U+- threshold
PLB706 (2012)
  2  90% C.L.
for 50 < MU < 420 MeV
PRL107 (2011)
PRL106 (2011)
C. Di Donato - Rencontres de Moriond QCD

11. U.L. can be improved by a factor 2
 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
C. Di Donato - Rencontres de Moriond QCD

12. Light Meson spectroscopy
+-
decay
C. Di Donato - Rencontres de Moriond QCD

13. 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) )
C. Di Donato - Rencontres de Moriond QCD

14. +- ++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% ) 14
C. Di Donato - Rencontres de Moriond QCD

15. , +-   2  clusters: |tcl-lcl/c|<5
2 Tracks closest to IP
1  clusters: E >250 MeV
Two body  decays constrain E
Kinematic from  decays constrain 
Main background +-0
BKG feature: in the 0 rest frame  are back to back ( < 165°)
TOF to reject e+e- background
Events/4 MeV
M
Signal in M +- window (539.5÷554.5) MeV
C. Di Donato - Rencontres de Moriond QCD

16. +-  Data sample L = 558 pb-1 Ng =204 950 =(21.310.04)%;
B/S=10%
Signal counting from
fit to E-P
C. Di Donato - Rencontres de Moriond QCD

17. Normalization Sample: +- 0

L = 558 pb-1
N =1´190103
=(22.770.02)%;
B/S=0.65%
e+e-
=41.8 0.2 nb
Composition
BR() =
(22.41 0.03 0.35)%
(systematics include: 0.5% (lumy)1%(x-sec.) 1% (evcl) 0,43% (cut analysis) = 1.56% )
PDG’10:BR()
= (22.74 0.28)%
C. Di Donato - Rencontres de Moriond QCD

18. +- ++0 
Measurement has been performed on L=558pb-1
N=204´950 and N = 1´190´000
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]
C. Di Donato - Rencontres de Moriond QCD

19. +- 
d/dM
Fit with Model independent method based on ChPT and dispersive analysis: (Stollenwerk, Hanhart, Kupsc, Meiner and Wirzba PLB707 (2012) )
C. Di Donato - Rencontres de Moriond QCD

20. Dipion Invariant Mass PLB707 (2012)
C. Di Donato - Rencontres de Moriond QCD

21. PRELIMINARY Dipion Invariant Mass
NTeo (taking into account efficiency and smearing)
Ndata
PRELIMINARY
[WASA Coll. PLB707 (2012) ]
C. Di Donato - Rencontres de Moriond QCD

22. 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
C. Di Donato - Rencontres de Moriond QCD

23. 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 e+e-→e+e-g*g*→e+e-X
Q-CALT/C-CALT: Increase acceptance for ’s from IP (21°→10°)
C. Di Donato - Rencontres de Moriond QCD

24. Conclusions
High statistic samples of light mesons allowed to perform precision measurement and to look for very rare decays
Analysis on full KLOE data set:
f → hU, h → p+p-p0 [PLB706 (2012) ]
h → p+p-g [Preliminary in arXiv: hep-ex]
gg → h/gg → p0p0 [arXiv: hep-ex]
 e+e- taggers in KLOE-2
p+p-g/m+m-g
New data in 2012: not stable running yet
C. Di Donato - Rencontres de Moriond QCD

25. SPARE
C. Di Donato - Rencontres de Moriond QCD

26. PLB706 (2012)
 e+ e- , with +-0
BR(e+e-)=1.15  10-4 : produced events  106 e+e-
 Ks KL
 peak
C. Di Donato - Rencontres de Moriond QCD

27. PLB706 (2012)
 e+ e- , with +-0
We have 14000 candidates: e+e- 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
C. Di Donato - Rencontres de Moriond QCD

28. Weizsäcker-Williams approx, |q2| << W2
 Physics:
Weizsäcker-Williams approx, |q2| << W2
Tagger is essential to reduce bckg
from f and to close kinematics  KLOE-2 X
Lint = 1 fb-1
2011/06/14

29.  Fusion @KLOE without tagger
C. Di Donato - Rencontres de Moriond QCD

30.  Fusion
C. Di Donato - Rencontres de Moriond QCD

31.  Fusion
C. Di Donato - Rencontres de Moriond QCD

32.  Fusion:
2011/06/14

33.  Fusion: PRELIMINARY @KLOE without tagger 240 pb-1 @ s = 1 GeV
8090 events after selections
Bkg normalized using x-sections
KSKL
ωπ0
f0γ