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CAMILLA DI DONATO SEZ. INFN NAPOLI ON BEHALF OF KLOE AND KLOE-2 COLLABORATIONS Hadron Physics at KLOE and KLOE-2

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Outline C. Di Donato - Rencontres de Moriond QCD 2 Hadron KLOE/2 U-boson Search: e + e - / U Light Meson Spectroscopy: and physics Other KLOE/2 results not discussed here PS Transition FF Physics: /f 0 (600) Study of (S/PS ) Pion FF from e + e - /

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

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

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

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Search for U KLOE C. Di Donato - Rencontres de Moriond QCD 6 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)

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e + e -, with BR( e + e - )= : produced events 10 6 e + e - L = 1.5 fb -1 PLB706 (2012) C. Di Donato - Rencontres de Moriond QCD 7

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e + e -, with We have candidates: e + e - with 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 8 PLB706 (2012)

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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 C. Di Donato - Rencontres de Moriond QCD 9

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Exclusion plot for Kinematic factors [Reece- Wang, JHEP0907:051 (200)] Opening of U + - threshold % C.L. for 50 < M U < 420 MeV Evaluation of UL takes into account: C. Di Donato - Rencontres de Moriond QCD 10 PLB706 (2012) PRL107 (2011) PRL106 (2011) PLB706 (2012)

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e + e -, with / Preliminary studies on and decay channels produce encouraging results U.L. can be improved by a factor 2 C. Di Donato - Rencontres de Moriond QCD 11

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+ - DECAY Light Meson spectroscopy C. Di Donato - Rencontres de Moriond QCD 12

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Light Mesons: + - C. Di Donato - Rencontres de Moriond QCD 13 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 / + - / - + VMDCT + 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 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) )

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C. Di Donato - Rencontres de Moriond QCD This analysis: L = 558 pb mesons (4.6% Theory HLS-Model: ( w = ( ) eV ( wo = ( ) eV ( = (60 4) eV [PDG] provide strong evidence in favour of BOX Anomaly 14

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

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+ - C. Di Donato - Rencontres de Moriond QCD 16 Data sample L = 558 pb -1 N = =( )%; B/S=10% Signal counting from fit to E-P

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Composition Normalization Sample: C. Di Donato - Rencontres de Moriond QCD 17 L = 558 pb -1 N =1 ´ =( )%; B/S=0.65% e + e - = nb BR( ) = ( )% (systematics include: 0.5% (lumy) 1%(x-sec.) 1% (evcl) 0,43% (cut analysis) = 1.56% ) PDG10:BR( ) = ( )%

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C. Di Donato - Rencontres de Moriond QCD 18 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 = ( ) eV ( wo = ( ) eV ( = (60 4) eV [PDG]

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

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

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

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DAFNE-Upgrade New scheme Old scheme C. Di Donato - Rencontres de Moriond QCD DA NE upgrade -New interaction scheme: large beam crossing angle + sextupoles for crab waist Luminosity increase: factor ~ 3; Ldt 1 pb -1 /hour 22

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KLOE Upgrade C. Di Donato - Rencontres de Moriond QCD 23 Minimal detector upgrade for first KLOE-2 run (5 fb -1 in 1 year): taggers to detect momentum of leptons in e + ee + ee + e X Inner Tracker: 4 layers of cylindrical triple GEM Q-CALT/C-CALT: Increase acceptance for s from IP (21° 10°)

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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: U, [PLB706 (2012) ] [Preliminary in arXiv: hep-ex] [arXiv: hep-ex] e+e- taggers in KLOE-2 New data in 2012: not stable running yet C. Di Donato - Rencontres de Moriond QCD 24

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SPARE C. Di Donato - Rencontres de Moriond QCD 25

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e + e -, with BR( e + e - )= : produced events 10 6 e + e - PLB706 (2012) C. Di Donato - Rencontres de Moriond QCD 26 peak K s K L

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e + e -, with We have candidates: e + e - with 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 27 PLB706 (2012)

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2011/06/14 28 Physics: X Weizsäcker-Williams approx, |q 2 | << W 2 Tagger is essential to reduce bckg from and to close kinematics KLOE-2 L int = 1 fb

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Fusion C. Di Donato - Rencontres de Moriond QCD without tagger

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Fusion C. Di Donato - Rencontres de Moriond QCD 30

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C. Di Donato - Rencontres de Moriond QCD 31 Fusion

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Fusion: 2011/06/14 32

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33 Fusion: without tagger KSKLKSKL ωπ 0 f0γf0γ 240 pb s = 1 GeV 8090 events after selections Bkg normalized using x-sections

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