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Paweł Moskal

MESON2012 12th International Workshop on Meson Production, Properties

and Interaction, Cracow, Poland, 31 May - 5 June 2012

Jagiellonian University, Cracow, Poland on behalf and for the WASA-at-COSY Collaboration

Studies of the eta meson decays with the WASA detector at COSY

WASA-at-COSY

searches for the phenomena beyond the applicability of

Standard Model of Particle Physics

Since nothing is more pleasurable than to falsify the theory !!

I thought… the scientific theories were not the digest of observation,but that they were inventions-conjectures boldly put forward for trialto be eliminated if they clashed with observation … David Hume

production and decay of the meson

Production:• test of charge symmetry • search for the eta-mesic nuclei• studies of ABC effect – new resonance?• hadronic interactions …

Decays: • test of discrete symmetries• search for dark matter boson• contributing to the study of aμ

• test of QCD anomalies• test of CHPT …

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

violates P and CP

violates G and ( I or C )

0γ , 00γ violates C

γγγ violates C etc…

Second order EM γγ is forbidden in a massless quarks limits

C() = +1 , P() =-1; C(0) = +1 , P(0) =-1

WASA-at-COSY

109 mesons on discs

this presentation is based on

~ 3 · 107

• polarised and unpolarised proton and deuteron beams

• stochastic and electron cooling

• momentum range: 600 – 3700 MeV/c

• meson production up to (1020)

WASA-at-COSY pp pp pd 3He


Today charged modes

- γ does not if L(+- ) = 1

00γ violates C

Phys. Lett. B707 (2012) 243 - Christoph Redmer, PhD thesis

- γ

L(- ) = 1

- γ

F. Stollenwerk, C. Hanhart, A. Kupść, U.G, Meissner, A. Wirzba,

Phys. Lett. B707 (2012) 184

factor of 100 more mesons collected by WASA-at-COSY

α = 1.89 ± 0.25± 0.59

Phys. Lett. B707 (2012) 243 Christoph Redmer, PhD thesis

suppresed by α- γ* -e+e-

- γ - γ* - e+e- - γ*

-e+e-flavour conserving CP violation

CP conservation implies N(φ) = N(180 – φ)

π+

π-

e+

e-

φ

π+

π-

e+e-

180ᵒ - φ

IN PREPARATION ….

-e+e-

-e+e-

-γ

-e+e-Daniel Coderre PhD thesis 2012

-e+e-


γγ e+e-

Suppressed by α2 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. A48 (2012) 64

Background: pp→pp+-, →e+e-, pp→p∆(1232)→pp[*→e+e-]based on 4.4 107 η mesonsBRlimit = 4.6×10−6 at CL 90% (preliminary)

factor of 20 more mesons collected by WASA-at-COSY MMpp for →e+e- event candidates

Poster by Marcin Berłowski

γγ* γe+e-

Suppressed by α

The anomalous muon magnetic moment a = (g - 2)/2 = (116592080 ± 60) 10-11

from E821 at BNL

theory : a = aQED + a

weak + a

had

γ γ* γ e+e-

Meson transition Form Factors

FNAL experiment plans to improve this accuaracy to 0.14 ppm M. Hodana, PhD thesis, arXiv:1203.5756

η π p

Particle's charge radius:

based on 107 eta mesons

hadronic light-by-light scattering


Suppressed by α

Suppressed by next factor of α 7 10-3 / 137 = 5 10-5

γγ* γe+e- γ*γ* e+e- e+e-

Oraz może pokazac e+e-e+e- wstepne na podstawie ….XXX* 10^7

KLOE

WASA-at-COSY

Neeee = 52 ± 13

factor of 30 more eta mesons on discs

γ*γ* e+e- e+e-

analysis: L. Yurev, P. Wurm

KLOE:


π+π-π0

π+π-π0


s1s2

s3

III

II

I

IV

VI

V

Poster by M. Zieliński


CP

darkmatter

C

…

THANK YOU FOR YOUR ATTENTION

ABC effect in double pionic fusion - a new resonance?

Phys. Rev. Lett. 106 (2011) 242302

Plenary talk by Anette Pricking: Monaday, June 4th, 13:00-13:30 Posters by Mikhail Bashkanov and Tatiana Skorodko

Cross section for pn → dπ0π0

++

Search for THE ETA-MESIC NUCLEUS

η meson bound with nucleus via STRONG INTERACTION

ηN*

N*N* π+

Talk by Wojciech Krzemień, Session B 17:30, 31.05 Thursday Poster by Magdalena Skurzok

Dalitz decay ω→π0e+e−

Talk by 17:10-17:30 Farha Anjum Khan, Friday, June 1-st, Session B2

Missing Mass of pd → 3He X after π0e+e− selection

THANK YOU FOR YOUR ATTENTION

13.6 ± 2.5 (stat) ± 1.2 (syst)%KTeV PRL 84 (2000) 408

-e+e-

10-310-12-10-15