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Decays and transition form factors of 0 , and ' mesons: status at KLOE/KLOE-2 and other experiments Andrzej Kupsc Uppsala University for the KLOE/KLOE-2 and for the WASA-at-COSY Collaborations Amherst, March 7th, 2014 Outline ,'

SLIDE 1

Amherst, March 7th, 2014

Decays and transition form factors

f π0, and η' mesons: status at

KLOE/KLOE-2 and other experiments

Andrzej Kupsc Uppsala University

for the KLOE/KLOE-2 and for the WASA-at-COSY Collaborations

SLIDE 2

Outline

η,η' factories/data samples (pd, pp, e+e-)
Selected results KLOE/WASA:

Transition Form Factors /Anomalous processes

γ∗γ

η → (Γγγ)

e+e-

→ ηγ

η → e+e-e+e- / e+e-

φ η/π → →

0e+e- (TFF)

π →

+π−γ

Even P processes

π →

+π−π0

SLIDE 3

Ben Nefkens Juliet Lee-Franzini Sven Kullander WASA CBall

π-p, γp

KLOE Saclay

pd pd, pp

SLIDE 4

CELSIUS <2005 COSY 2007 – 2014 WASA Proposal 1987: key experiments: π0,η e →

+e-

SLIDE 5

Meson tagging pp pp → π0 pd→3Heη pp→ppη

>5x108 1010

SLIDE 6

BEPC II DAΦNE VEPP 2000

e+e- colliders

BEPCII L=6x1032 cm-2s-1 at J/Ψ DAΦNE L= 1032 cm-2s-1 at φ VEPP2000 L= 1032 cm-2s-1 at 2GeV BESIII KLOE/KLOE-2 CMD-3,SND

SLIDE 7

φ (1020) a0(980) f0(980) η(550) η'(960) γ ρ(770) KK π

0- 0- 1- 1- 0+ 0+

π0

BR = 83%

BR = 15% BR = 1.3%

BR = 6.2×10−5

BR = 1.3×10−3 BR ~ O(10−4)

+ scan ±20 MeV ∼ Ο(10 pb−1)

γ* →(φ) → Hadrons (KLOE)

σT (1GeV) 80 nb

KLOE 2001-2005 data √s

1x108 η 0.5x106 η′

SLIDE 8

ISR γγ

T a g g e r s

KLOE: Fv(W) in e+e-→π+π-(γ)

L u m i n

i t y

W<√s

√s

SLIDE 9

DAΦNE luminosity upgrade

Frascati φ-factory

e+e- collider √s = Mφ

PRL104 (2010) 174801

Luminosity vs currents product LNEW=3xLOLD

Novel interaction scheme: large angle beam crossing + crabbed waist sextupoles

KLOE-2 IP collisions: from 2010 Commissioning for KLOE-2 Status:L=1.5 x 1032 cm-2s-1 with 1.3 A + 700/800 mA, 7pb-1/day

KLOE-2: Extension of the KLOE physics program at upgraded DAΦNE

SLIDE 10

KLOE KLOE-2 →

Inner Tracker: cyl. GEM

Small angle EMC

Upgrades

2+2 taggers for: e+e−→e+e−γ∗γ∗→e+e−X

R e a d y l a s t J u l y

Drift Chamber

δpT~0.4% (θ<45o)

EM Calorimeter

δE/E=5.7/√E % δt=57/√E⊕100 ps

SLIDE 11

SLIDE 12

Low Energy QCD processes

Even # pseudoscalars PPPP Anomalous: odd # pseudoscalars: PVV(Pγγ), PPPV u-d quark masses π-π,π-η scattering

Vector Meson Dominance: V0 ↔ γ

V PV →

SLIDE 13

Structure of light mesons L/H energy QDC LAB l+l- spectra in HIon

Pseudoscalar Transition Form Factors (TFF)

MesonNet(HP3) Workshop on Meson Transition Form Factors May 29-30,2012 Kraków

g-2 LbL Dark photon P l+l- → Fπ0 q2→∞ puzzle η: Γγγ mu/md

SLIDE 14

Radiative widths of η,π0 η, π0 : narrow and short lived => Гtot=Гγγ/BRγγ Two exp. techniques: γZ → η,π0 Primakoff e+e-: γγ η,π →

δΓ(η γγ) → ~5% δΓ(π 0 γγ) → ~2.8%

PrimEx PRL 106,162303(2011) [KLOE JHEP1301 (2013) 119]

Γγγ=520±20stat±13syst eV

KLOE-2 Taggers  5fb-1 => δГ(π0

γγ) →

~1%

SLIDE 15

TFF kinematic regions: π0,η

γγ→P γγ→P P→γγ γ→Pγ γ→Pγ γ * → P γ * γ→Pγ

π0 η

SLIDE 16

η,π0 single off shell TFF

Data:CELLO,NA60,CB-MAMI,CMD-2,SND

γγ*→π0

ISR ISR

VEPP 2000 0.3-2GeV KLOE-2 ISR, BESIII

BESIII
Belle
KLOE-2

Dalitz decays: KLOE, WASA,CBall,BESIII CLAS,NA48

γ→Pγ P→γγ

GlueX

SLIDE 17

SLIDE 18

Dalitz decays

η → e+e-γ FF=1 η → e+e-γ π0 → e+e-γ

SLIDE 19

Vertex r 20 mm + PID MC MC Data

Analysis: π0 → γe+e-

Vertex r (cyl)

SLIDE 20

σ(e+e- → π0γ,ηγ)

Data: CMD-2,SND

SLIDE 21

e+e- → ηγ at 1 GeV

KLOE JHEP1301 (2013) 119

SLIDE 22

ω→π0γ* γ*→φ→π0γ* e+e-→π0ω γ*→φ→ηγ*

γ*γ*→π0 γ*γ*→η

KLOE prel result bη(m2

φ)

φ→ηγ* BR 10-4 Naive VMD: Black: bπ Red: bη bπ0(m2

φ) φ→π0γ* BR 10-5

slopes bπ, bη

TH: Bastian talk → Relation to ω/φ→π+π-π0

V P → γ* and e+e- PV processes →

SLIDE 23

Double off shell TFF

γ→φ→ηγ

First observation!

L=1.7 fb-1

η

SLIDE 24

η meson radiative decay width η π →

+π−π0

η π →

0π0π0

Insensitive to TFF

Γγγ=520±20±13 eV L=240 pb-1

32.0±1.5 ±0.9 pb 34.5±2.5 ±1.0 pb

SLIDE 25

Form factor/BR: U boson limits

η π →

0π0π0

31k events

φ e →

+e-η

η π →

+π−π0

13k events PRL106 PRL107

SLIDE 26

9k events Background radiative Bhabha andφ π0γ → efficiency: 15% 2% → low high q → Analysis in progress: background subtraction + global efficiency

φ e →

+e-π0

SLIDE 27

SLIDE 28

Dorokhov,PLB667,145 3σ diff

π0/η η'/η

e+ e+ e- e-

HADES WASA CBall NA48/NA62 Decay Formation Searches using formation: e+e- → η' , L=0.5pb-1 => B< 2.1·10-7 90% CL Vorobev SJNP 48(1988)273

SLIDE 29

η π →

+π−γ/η

π →

+π−π0

No kin fit:use DC resolution
Not use EMC Energy

205 k events eff=21% S/B=10

Normalization

Φ ηγ → L = 558 pb-1

η π →

+π−π0

η π →

+π−γ

Consistent with CLEO

SLIDE 30

η π →

+π−γ

Fit data [WASA PLB707 (2012) 243]

67 83

= Ndf χ

α=1.31±0.08stat±0.40systv GeV-2

PLB707 (2012) 184

e+e-→π+π-

Mππ=√s

[KLOE PLB718 (2013) 910]

α=1.89±0.25stat±0.59syst GeV-2

SLIDE 31

From η π →

+π−γ to η

→ e+e−γ

sππ [GeV2] WASA,KLOE: A+α => bη(0)=2.05+0.22 GeV-2

0.10

EPJC73(13)2668

Mππ=√s

η' π →

+π-γ

BESIII CLAS

DATA: C Barrel PLB 402,195 ('97); KLOE PL B718, 910 ('13)

SLIDE 32

BESIII PRD87, 092001('13)

158916±425

BESIII data sample on η' π →

+π−γ

SLIDE 33

Dominant VMD contribution BRx104 VMD Exp η π →

0γγ 2.1 2.7 ± 0.5 PDG

η′ → ω[π0γ]γ 52 η′ π →

0γγ 3 <8 (90% CL) GAMS(87)

η′ ηγγ 2.5 — →

η/η′ π →

0γγ

η′ π →

0γγ 80% ω 4.6% ρ (+15% ρω interf? and φ)

Escribano (arXiv:1207.5400)

SLIDE 34

ω+ρ ρ

SLIDE 35

Three body decays, Dalitz plot

3 body decay: 0 1 + 2 + 3 → si ( ≡ p0−pi)2 = (m0−mi)2-2Tim0

|A(X,Y)|2=N(1+aY+bY2+dX2+fY3+gX2Y) η´ π+π-η →

EXP: CBall, KLOE,WASA, VES, BESIII

BESIII PRD83, 012003('11)

SLIDE 36

KLOE2008 analysis (JHEP 0805,006) 0.45 fb-1 1.34·10 ⇒

6 events in DP

large syst. uncertainty due to Event classification New analysis: 1.7 fb-1 4.48·10 ⇒

6 events in DP

new analysis scheme improved MC new cross checks

New analysis PRELIMINARY (no syst. ): f≠0 confirmed fits with g...

|A(X,Y)|2=N(1+aY+bY2+dX2+fY3+gX2Y)

a b d f JHEP0805,006 1.090(5)( ‐

+8) 0.124(6)(10)

0.057(6)( +7 ) 0.140(10)(20) preliminary, 1.103(3)(?) ‐ 0.142(3)(?) 0.073(3)(?) 0.154( 6)(?) 2013

‐19 ‐16

KLOE new prel. DP η π →

+π−π0

SLIDE 37

WASA-at-COSY new prel. DP η π →

+π−π0

a b d f preliminary, 1.144(18) ‐ 0.219(19)(37) 0.086(18)(18) 0.115(37) 2013

1.5·105 events

SLIDE 38

U(3) CHPT, Borasoy, Nißler 2005: BR(η π →

+π−π0) ≈ 1.8% large ρ±π0

η´ πππ →

SLIDE 39

The data 20±5 ev. BR= 3.7±1.0 10-3 CLEO: PRL 102, 061801 (2009) Z=x2+y2 GAMS PAN71,2124('08) 235 ± 45 (1.8 ± 0.4) × 10−3 Z=x2+y2

η´ πππ →

SLIDE 40

1014±39 309±19 BESIII, PRL 108,182001 (2012) BR=(3.83± 0.15± 0.39)x10-3 BR=(3.56± 0.22± 0.34)x10-3

η´ π+π-π → η´ π →

0π0π0

Amherst, March 7th, 2014

Decays and transition form factors

KLOE/KLOE-2 and other experiments

Andrzej Kupsc Uppsala University

for the KLOE/KLOE-2 and for the WASA-at-COSY Collaborations

Outline

Transition Form Factors /Anomalous processes

η → (Γγγ)

→ ηγ

φ η/π → →

π →

Even P processes

π →

Ben Nefkens Juliet Lee-Franzini Sven Kullander WASA CBall

π-p, γp

KLOE Saclay

pd pd, pp

Meson tagging pp pp → π0 pd→3Heη pp→ppη

>5x108 1010

e+e- colliders

BEPCII L=6x1032 cm-2s-1 at J/Ψ DAΦNE L= 1032 cm-2s-1 at φ VEPP2000 L= 1032 cm-2s-1 at 2GeV BESIII KLOE/KLOE-2 CMD-3,SND

φ (1020) a0(980) f0(980) η(550) η'(960) γ ρ(770) KK π

π0

+ scan ±20 MeV ∼ Ο(10 pb−1)

γ* →(φ) → Hadrons (KLOE)

σT (1GeV) 80 nb

KLOE 2001-2005 data √s

1x108 η 0.5x106 η′

ISR γγ

T a g g e r s

KLOE: Fv(W) in e+e-→π+π-(γ)

L u m i n

i t y

W<√s

√s

DAΦNE luminosity upgrade

Frascati φ-factory

e+e- collider √s = Mφ

Novel interaction scheme: large angle beam crossing + crabbed waist sextupoles

KLOE-2: Extension of the KLOE physics program at upgraded DAΦNE

KLOE KLOE-2 →

Inner Tracker: cyl. GEM

Small angle EMC

Upgrades

2+2 taggers for: e+e−→e+e−γ∗γ∗→e+e−X

R e a d y l a s t J u l y

Drift Chamber

δpT~0.4% (θ<45o)

EM Calorimeter

δE/E=5.7/√E % δt=57/√E⊕100 ps

Low Energy QCD processes

Even # pseudoscalars PPPP Anomalous: odd # pseudoscalars: PVV(Pγγ), PPPV u-d quark masses π-π,π-η scattering

Vector Meson Dominance: V0 ↔ γ

V PV →

Structure of light mesons L/H energy QDC LAB l+l- spectra in HIon

Pseudoscalar Transition Form Factors (TFF)

g-2 LbL Dark photon P l+l- → Fπ0 q2→∞ puzzle η: Γγγ mu/md

Radiative widths of η,π0 η, π0 : narrow and short lived => Гtot=Гγγ/BRγγ Two exp. techniques: γZ → η,π0 Primakoff e+e-: γγ η,π →

δΓ(η γγ) → ~5% δΓ(π 0 γγ) → ~2.8%

Γγγ=520±20stat±13syst eV

KLOE-2 Taggers  5fb-1 => δГ(π0

γγ) →

~1%

TFF kinematic regions: π0,η

γ*γ*→P γ*γ*→P P→γ*γ* γ*→Pγ* γ*→Pγ* γ * → P γ * γ*→Pγ*

π0 η

η,π0 single off shell TFF

γγ*→π0

VEPP 2000 0.3-2GeV KLOE-2 ISR, BESIII

Dalitz decays: KLOE, WASA,CBall,BESIII CLAS,NA48

γ*→Pγ P→γ*γ

Dalitz decays

η → e+e-γ FF=1 η → e+e-γ π0 → e+e-γ

Analysis: π0 → γe+e-

σ(e+e- → π0γ,ηγ)

e+e- → ηγ at 1 GeV

KLOE prel result bη(m2

slopes bπ, bη

TH: Bastian talk → Relation to ω/φ→π+π-π0

V P → γ* and e+e- PV processes →

γγ→P γγ→P P→γγ γ→Pγ γ→Pγ γ * → P γ * γ→Pγ

γ→Pγ P→γγ

γ→φ→ηγ