Studies of the eta meson decays with the

Studies of the eta meson decays with the WASA detector at COSY Paweł Moskal Jagiellonian University, Cracow, Poland on behalf and for the WASA-at-COSY Collaboration MESON 2012 12 th International Workshop on Meson Production, Properties and Interaction, Cracow, Poland, 31 May - 5 June 2012

WASA-at-COSY searches for the phenomena beyond the applicability of Standard Model of Particle Physics Since nothing is more pleasurable than to falsify theory !! I thought… the scientific theories were not the digest of observation, but that they were inventions-conjectures boldly put forward for trial to be eliminated if they clashed with observation … David Hume

production and decay of the meson Decays: • • • test of discrete symmetries search for dark matter boson contributing to the study of aμ test of QCD anomalies test of CHPT … Production: • • test of charge symmetry search for the eta-mesic nuclei studies of ABC effect – new resonance? hadronic interactions …

production and decay of the meson Decays: • • • test of discrete symmetries search for dark matter boson contributing to the study of aμ test of QCD anomalies test of CHPT … Production: • • test of charge symmetry search for the eta-mesic nuclei studies of ABC effect – new resonance? hadronic interactions …

decay: meson C P CP +1 -1 -1 All strong and electromagentic decays are forbidden in a first order In SM weak decays are expected to occur at 10 -13 PRECISE TESTS OF DISCRETE SYMMETRIES

C( ) = +1 , P( ) =-1; C( 0) = +1 , P( 0) =-1 violates P and CP violates G and ( I or C ) 0γ , 0 0γ violates C Second order EM γγ is forbidden in a massless quarks limits γγγ violates C etc…

WASA-at-COSY 9 10 mesons on discs this presentation is based on 7 ~ 3 · 10

WASA

WASA-at-COSY pp pp pd • polarised and unpolarised proton and deuteron beams • stochastic and electron cooling • momentum range: 600 – 3700 Me. V/c • meson production up to (1020) 3 He

WASA-at-COSY pp pp pd 3 He

WASA-at-COSY pp pp pd 3 He

WASA-at-COSY pp pp pd Today charged modes 3 He

0 0γ violates C - γ does not if L( + - ) = 1

γ L( - ) = 1 Phys. Lett. B 707 (2012) 243 - Christoph Redmer, Ph. D thesis

γ F. Stollenwerk, C. Hanhart, A. Kupść, U. G, Meissner, A. Wirzba, Phys. Lett. B 707 (2012) 184 α = 1. 89 ± 0. 25± 0. 59 Phys. Lett. B 707 (2012) 243 Christoph Redmer, Ph. D thesis factor of 100 more mesons collected by WASA-at-COSY

- γ γ* - e+e- suppresed by α - γ* -e+e-

+ e e flavour conserving CP violation 180ᵒ - φ e+ φ π+ eπ- π+ e- e+ π- CP conservation implies N(φ) = N(180 – φ)

+ e e IN PREPARATION ….

+ e e Daniel Coderre Ph. D thesis 2012

+ e e factor of 30 more mesons collected by WASA-at-COSY

γγ e+e. Suppressed by α 2 and by (me/m )2 10 -9 Sensitive to hypothetical interactions from beyond the Standard Model

e+e. HADES Collaboration: < 5. 6· 10 -6 at CL=90% ) Eur. J. Phys. A 48 (2012) 64 Poster by Marcin Berłowski Background: pp→pp + -, →e+e- , pp→p∆(1232)→pp[ *→e+e-] based on 4. 4 107 η mesons BRlimit = 4. 6× 10− 6 at CL 90% (preliminary) MMpp for →e+e- event candidates factor of 20 more mesons collected by WASA-at-COSY

γγ* γe+e. Suppressed by α

γ γ* γ + ee Meson transition Form Factors The anomalous muon magnetic moment a = (g - 2)/2 = (116592080 ± 60) 10 -11 from E 821 at BNL FNAL experiment plans to improve this accuaracy to 0. 14 ppm theory : a = a QED + a weak + a had M. Hodana, Ph. D thesis, ar. Xiv: 1203. 5756 hadronic light-by-light scattering Particle's charge radius: η π p based on 107 eta mesons factor of 100 more mesons collected by WASA-at-COSY

γγ* γe+e γ*γ* e+e- Suppressed by α Suppressed by next factor of α 7 10 -3 / 137 = 5 10 -5

γ*γ* e+e- e+e. KLOE: Neeee = 52 ± 13 WASA-at-COSY analysis: L. Yurev, P. Wurm factor of 30 more eta mesons on discs factor of 30 more mesons collected by WASA-at-COSY

π+π-π0 s 2 s 3 VI I V s 1 II IV III Poster by M. Zieliński factor of 30 more mesons collected by WASA-at-COSY

CP dark matter C …

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ABC effect in double pionic fusion - a new resonance? Cross section for pn → dπ0π0 Phys. Rev. Lett. 106 (2011) 242302 Plenary talk by Anette Pricking: Monaday, June 4 th, 13: 00 -13: 30 Posters by Mikhail Bashkanov and Tatiana Skorodko

Search for THE ETA-MESIC NUCLEUS η meson bound with nucleus via STRONG INTERACTION + + N* N* N* + η π Talk by Wojciech Krzemień, Session B 17: 30, 31. 05 Thursday Poster by Magdalena Skurzok

Dalitz decay ω→π0 e+e− Missing Mass of pd → 3 He X after π0 e+e− selection Talk by 17: 10 -17: 30 Farha Anjum Khan, Friday, June 1 -st, Session B 2

THANK YOU FOR YOUR ATTENTION

+ e e 10 -12 -10 -15 10 -3 13. 6 ± 2. 5 (stat) ± 1. 2 (syst)% KTe. V PRL 84 (2000) 408