Hadronic Decays of the Meson Lena Heijkenskj old Uppsala - PowerPoint PPT Presentation

Part II: WASA ω → π + π − signal Introduction Part I: WASA Dalitz plot Part II: KLOE simulation study Hadronic Decays of the ω Meson Lena Heijkenskj¨ old Uppsala University L. Heijkenskj¨ old (Uppsala University) Hadronic Decays of the ω Meson 1 / 31

Part II: WASA ω → π + π − signal Introduction Part I: WASA Dalitz plot Part II: KLOE simulation study Standard Model Three fundamental forces Electro- Strong Weak Magnetism Quantum Chromo Electro-Weak Dynamics theory Prevailed a multitude of test L. Heijkenskj¨ old (Uppsala University) Hadronic Decays of the ω Meson 2 / 31

Part II: WASA ω → π + π − signal Introduction Part I: WASA Dalitz plot Part II: KLOE simulation study Standard Model Three fundamental forces Electro- Strong Weak Magnetism Quantum Chromo Electro-Weak Dynamics theory Prevailed a multitude of test Hint of physics beyond SM: · = g µ − 2 anomalous magnetic moment of the muon a µ · 2 =116592091(54)(33) × 10 − 11 a exp µ a SM = a QED + a EW + a Had =116591803(1)(42)(26) × 10 − 11 µ µ µ µ 3.6 σ discrepancy → physics beyond the standard model L. Heijkenskj¨ old (Uppsala University) Hadronic Decays of the ω Meson 2 / 31

Part II: WASA ω → π + π − signal Introduction Part I: WASA Dalitz plot Part II: KLOE simulation study Hadron Physics Calculations in the lower energy (Q) regime Q October 2015 τ decays (N 3 LO) α s (Q 2 ) DIS jets (NLO) Heavy Quarkonia (NLO) Elementary particles Perturbative QCD applicable e + e – jets & shapes (res. NNLO) 0.3 e.w. precision fits (NNLO) ( – ) pp –> jets (NLO ) pp –> tt (NNLO) 0.2 Phenomenological models and Effective Field Theories Hadrons 0.1 QCD α s (M z ) = 0.1181 ± 0.0013 or Lattice QCD 1 10 100 1000 Q [GeV] L. Heijkenskj¨ old (Uppsala University) Hadronic Decays of the ω Meson 3 / 31

Part II: WASA ω → π + π − signal Introduction Part I: WASA Dalitz plot Part II: KLOE simulation study Hadron Physics Calculations in the lower energy (Q) regime Q October 2015 τ decays (N 3 LO) α s (Q 2 ) DIS jets (NLO) Heavy Quarkonia (NLO) Elementary particles Perturbative QCD applicable e + e – jets & shapes (res. NNLO) 0.3 e.w. precision fits (NNLO) ( – ) pp –> jets (NLO ) pp –> tt (NNLO) 0.2 Phenomenological models and Effective Field Theories Hadrons 0.1 QCD α s (M z ) = 0.1181 ± 0.0013 or Lattice QCD 1 10 100 1000 Q [GeV] Quark Model J P = 0 − J P = 1 − Y K ∗ 0 K ∗ + K 0 K + Composite objects: 1 Baryons - qqq η π 0 ω ρ 0 Mesons - q ¯ q ρ − ρ + π − π + 0 η ’ φ Classification in Y and I 3 -1 K − ¯ K ∗− K ∗ 0 ¯ K 0 I 3 I 3 -1 0 1 -1 0 1 L. Heijkenskj¨ old (Uppsala University) Hadronic Decays of the ω Meson 3 / 31

Part II: WASA ω → π + π − signal Introduction Part I: WASA Dalitz plot Part II: KLOE simulation study This thesis The ω meson I G ( J PC ) = 0 − (1 −− ) σ ( e + e − → Hadrons ) -2 10 m ω = 782.65(12) MeV, Γ ω = 8.49(8) MeV ω φ J / ψ -3 10 ψ (2S) Υ ρ ′ ρ -4 Z ω → Γ i / Γ ω 10 σ [mb] -5 10 π + π − π 0 89.2(7)% -6 10 π 0 γ 8.28(28)% -7 10 π + π − 1 . 53 +0 . 11 − 0 . 13 % -8 10 √ s [GeV] 2 1 10 10 L. Heijkenskj¨ old (Uppsala University) Hadronic Decays of the ω Meson 4 / 31

Part II: WASA ω → π + π − signal Introduction Part I: WASA Dalitz plot Part II: KLOE simulation study This thesis The ω meson I G ( J PC ) = 0 − (1 −− ) σ ( e + e − → Hadrons ) -2 10 m ω = 782.65(12) MeV, Γ ω = 8.49(8) MeV ω φ J / ψ -3 10 ψ (2S) Υ ρ ′ ρ -4 Z ω → Γ i / Γ ω 10 σ [mb] -5 10 π + π − π 0 89.2(7)% -6 10 π 0 γ 8.28(28)% -7 10 π + π − 1 . 53 +0 . 11 − 0 . 13 % -8 10 √ s [GeV] 2 1 10 10 Thesis outline Part I: Part II: ω → π + π − π 0 Dalitz plot study with Additional ω studies WASA-at-COSY – Search for ω → π + π − signal with Theory, WASA experiment, Analysis, Results WASA-at-COSY – Simulation study of π 0 π 0 interference for ω Dalitz plot measurement using KLOE data L. Heijkenskj¨ old (Uppsala University) Hadronic Decays of the ω Meson 4 / 31

Part II: WASA ω → π + π − signal Introduction Part I: WASA Dalitz plot Part II: KLOE simulation study Part I: ω → π + π − π 0 Dalitz plot study with WASA-at-COSY × -6 10 0.1 0.08 0.06 0.04 0.02 0 00.1 3 0.20.30.40.50.60.70.80.9 2 1 0 Φ -1 Z -2 -3 1 L. Heijkenskj¨ old (Uppsala University) Hadronic Decays of the ω Meson 5 / 31

Part II: WASA ω → π + π − signal Introduction Part I: WASA Dalitz plot Part II: KLOE simulation study What is a Dalitz plot? 3-body decay s ij = | P i + P j | 2 0.5 1 0.45 0 0.4 ] 0.35 2 2 [GeV 0.3 3 0.25 23 0.2 s 0.15 0.1 M given by two independent variables 0.05 → 2D representation, e.g. M ( s 12 , s 23 ) 0 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 d 2 Γ 1 1 2 32 m 3 |M| 2 ds 12 ds 23 = s [GeV ] (2 π ) 3 12 L. Heijkenskj¨ old (Uppsala University) Hadronic Decays of the ω Meson 6 / 31

Part II: WASA ω → π + π − signal Introduction Part I: WASA Dalitz plot Part II: KLOE simulation study What is a Dalitz plot? 3-body decay s ij = | P i + P j | 2 0.5 1 0.45 0 0.4 ] 0.35 2 2 [GeV 0.3 3 0.25 23 0.2 s 0.15 0.1 M given by two independent variables 0.05 → 2D representation, e.g. M ( s 12 , s 23 ) 0 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 d 2 Γ 1 1 2 32 m 3 |M| 2 ds 12 ds 23 = s [GeV ] (2 π ) 3 12 Common choice of variables when m 1 = m 2 3 1 2 0.5 √ 3 T ∗ 1 − T ∗ Z = X 2 + Y 2 2 1 X = Q Y Φ Φ = tan − 1 X 0 0 Y = (2 m 1 + m 3 ) T ∗ 3 Y − 1 -1 -0.5 ( m 1 Q ) -2 -1 -3 -1 -0.5 0 0.5 1 0 0.2 0.4 0.6 0.8 1 X Z L. Heijkenskj¨ old (Uppsala University) Hadronic Decays of the ω Meson 6 / 31

Part II: WASA ω → π + π − signal Introduction Part I: WASA Dalitz plot Part II: KLOE simulation study ω → π + π − π 0 dynamics - 1 |M| 2 = 1 Dalitz plot density distribution ∼ |M ( s 12 , s 23 ) | 2 , : Phase space Restrictions from quantum numbers P - wave phase space ω : I ( J P ) = 0(1 − ) J 3 π = 1 and J 2 π = 1 |M| 2 = P ∝ | ¯ p j | 2 p i × ¯ × -6 10 × -6 10 0.1 0.1 0.08 0.08 0.06 0.04 0.06 0.02 0.04 0 1 0.02 0.5 0 00.1 3 1 0 0.20.30.40.50.60.70.80.9 2 Y 0.5 1 0 -0.5 0 -1 Φ Z -0.5 X -2 -1 -1 1 -3 L. Heijkenskj¨ old (Uppsala University) Hadronic Decays of the ω Meson 7 / 31

Part II: WASA ω → π + π − signal Introduction Part I: WASA Dalitz plot Part II: KLOE simulation study ω → π + π − π 0 dynamics - 2 |M| 2 / P π − π interactions π Intermediate ρ ω π π − π rescattering ρ π 1 Lagrangian approach 1 2 Dispersion approach 2 π π V → ππ ω ↓ π V → πππ ρ π d 2 Γ Predictions of ds 12 ds 23 1C. Terschl¨ usen, B. Strandberg, S. Leupold, F. Eichst¨ adt Eur.Phys.J. A49 (2013) 116 2S.P. Schneider, et al., Eur.Phys.J. C72 (2014) 2012 and Danilkin, et al. Phys. Rev. D91 (2015) 094029 L. Heijkenskj¨ old (Uppsala University) Hadronic Decays of the ω Meson 8 / 31

Part II: WASA ω → π + π − signal Introduction Part I: WASA Dalitz plot Part II: KLOE simulation study ω → π + π − π 0 dynamics - 2 |M| 2 / P π − π interactions π Intermediate ρ ω π π − π rescattering ρ π 1 Lagrangian approach 1 2 Dispersion approach 2 π π V → ππ ω ↓ π V → πππ ρ π d 2 Γ Predictions of ds 12 ds 23 Experiment - Theory comparison Parametrisation F ( Z , Φ) × P F ( Z , Φ) = 1 + 2 α Z + 2 β Z 3 / 2 sin(3Φ) + 2 γ Z 2 + 2 δ Z 5 / 2 sin(3Φ) + O ( Z 3 ) Fits are performed on theory predictions. 1C. Terschl¨ usen, B. Strandberg, S. Leupold, F. Eichst¨ adt Eur.Phys.J. A49 (2013) 116 2S.P. Schneider, et al., Eur.Phys.J. C72 (2014) 2012 and Danilkin, et al. Phys. Rev. D91 (2015) 094029 L. Heijkenskj¨ old (Uppsala University) Hadronic Decays of the ω Meson 8 / 31

Part II: WASA ω → π + π − signal Introduction Part I: WASA Dalitz plot Part II: KLOE simulation study Why study ω → π + π − π 0 dynamics? Previous measurement Largest previous statistics for study of the dynamics - 4200 events. Unable to distinguish ρ onset. L. Heijkenskj¨ old (Uppsala University) Hadronic Decays of the ω Meson 9 / 31

Part II: WASA ω → π + π − signal Introduction Part I: WASA Dalitz plot Part II: KLOE simulation study Why study ω → π + π − π 0 dynamics? Previous measurement Largest previous statistics for study of the dynamics - 4200 events. Unable to distinguish ρ onset. Benchmark for meson transition form factors γ ∗ γ ∗ ω Probe of hadron structure π 0 π 0 a part of Contribution to HLbL (muon g-2) ρ γ ∗ γ ∗ L. Heijkenskj¨ old (Uppsala University) Hadronic Decays of the ω Meson 9 / 31

Part II: WASA ω → π + π − signal Introduction Part I: WASA Dalitz plot Part II: KLOE simulation study Experimental setup Wide Angle Shower Apparatus Ex t rac t ion ANK E RF c avit y J ESSICA ooling JULIC PAX TOF icc hast Elec ron t c ooler oc St EDDA WASA Quadrupole Barrier buc k et c avit y COSY at Forschungszentrum Dipole J¨ ulich, Germany L. Heijkenskj¨ old (Uppsala University) Hadronic Decays of the ω Meson 10 / 31