Physics at COSY-Jülich

1. Baryons´10, Osaka (Japan), December 7-11, 2010 Physics at COSY-Jülich December 2010 | Hans Ströher (Forschungszentrum Jülich, Univ. Cologne)

2. COSY – COoler SYnchrotron Cooler and storage ring for (polarized) protons and deuterons p = 0.3 – 3.7 GeV/c Phase space cooled internal & extracted beams COSY … the machine for hadron spin physics Injector cyclotron

3. COSY – Experimental Facilities • Hadron physics with hadronic probes • Experimental set-ups: • ANKE • WASA • EDM • TOF • NEW: • PAX WASA ANKE EDM PAX TOF … the machine for hadron spin physics

4. Overview • Recentresults: • Nucleon-nucleonprogram • Di-proton final states S. Dymov (Friday, Dec. 10) • Strangenessprogram • L und S(+,0,-)production • Symmetriesprogram • p0, h, h´ decays  S. Schadmand (Friday, Dec. 10) • ABC effect • Nuclearprogram • fproduction • Polarized (Anti-)protons • Spin transfer • Spin filtering (at COSY, AD/CERN) • Future Plans: • Electric Dipole Moment (EDM) search

5. Recent Results – Di-protons (ANKE) • Di-proton: {pp}in 1S0state (Epp < 3 MeV) • Inverse photodisintegration: pp  {pp}sg • Deuteron breakup: dp  {pp}s n (polarized beam) • Deuteron breakup: dp  {pp}sD0 (polarized beam) • Pion production: pN  {pp}sp (polarized beamandtarget) • Deuteron breakup: dp  {pp}s n (polarized beam andtarget) p0New! p-New! LEC

6. Recent Results – Strangeness (ANKE) • Hyperon production in nucleon-nucleoncollisions • Lproduction: pp  K+ p L • S0production: pp  K+ p S0 • Y*production: pp  K+ p L(1405)/S0(1385) • S+production: pp  K+ n S+ • S-production: pn  K+ p S- Eur. Phys. J. A 46 (2010) Phys. Rev. C 81 (2010) s (mb) New! L S+ S0

7. Recent Results – Nuclear (ANKE) • Nuclearf-production: p A  f X  (K+K-) X • Transparencyratio R  massdependence: A(0.58 +- 0.03) • Momentumdependenceof R • Models indicatein-medium f-width an order-of-magnitude larger thanfreeG Phys. Lett. B (2010) in print Model-dependent analyses (Paryev; Oset et al.) New! New! < pf> = 1.1 GeV/c R

8. Recent Results – Symmetries (WASA) • Symmetry in p0, handh´decays: • Isospinsymmetryh  3p • Box anomalyh  p+p- g • Transition form factorh  e+e-gande+e- e+e- • CPV h  e+e- p+p- • Standard Model p0  e+e- Phys. Lett. B 677 (2009) New! New!

9. Recent Results – ABC (WASA) • ABC-effect (-puzzle): • low2p-massenhancement in isoscalarchannel • connectedwithisoscalar NN-pair • correlatedwithDDexcitation ? • pn  d p0p0 ; dd  ap0p0 --- Resonant structure: Whatisit? … also havedata on pd, dd  3He pp n, pp  {pp}spp, pd  pdpp New! New!

10. Recent Results – Polarization (PAX) • Howtoproduce a beam ofpolarized anti-protons ? • Test ofspin-flip (spintransferlepton hadron) • COSY experiment: depolarizationof a polarizedproton beam byunpolarizedelectrons (ofdetuned e-cooler)  crosssectionmuchtoosmalltoprovide a viabletoolforpolarizing anti-protons  methodofchoice: spin-filtering s < 107 b !! Phys. Lett. B 674 (2009) 99 (90)% CL

11. Plans – Polarized Antiprotons (PAX) Spin-filtering: repeated interaction of the beam with a polarized target „low-ß section“ Protons (FILTEX  COSY), anti-protons (CERN/AD) ABS, BRP ANKE PAX

12. COSY – COoler SYnchrotron Cooler and storage ring for (polarized) protons and deuterons p = 0.3 – 3.7 GeV/c Phase space cooled internal & extracted beams COSY … an ideal starting point for a srEDM search Injector cyclotron

13. Future plans – EDM • Upper limits for eEDM, µEDM, nEDM, …; new measurements … • NEW: Search for hadronic EDMs of charged particles (p, d,3He) with • polarized beams in a storage ring • Why another EDM-experiment ? • New approach • Potentially highly competitive sensitivity (<10-29 e cm) • Neutron and proton: complementarity (CQM) dn = 4/3 dd – 1/3 du dp = 4/3 du – 1/3 dd • (If finite dn was found  what is dp ?) • Deuteron is more than proton and neutron dd = dn + dp + dpNN

14. EDM at COSY – Method (I) Spin precession in an electromagnetic field Particles in storage ring with spin along momentum (frozen spin)  Observation of a transversal spin- component in a radial E-field ( d x E ): Impuls Spin

15. EDM at COSY – Method (II) Proton: (a = 1.79) B = 0: „Magic“ momentum:  purely electrostatic ring !

16. EDM at COSY – Method (II) • Proton: (a = 1.79) • magic momentum: pp = 0.701 GeV/c • no magnetic field: BV = 0 T • radial E-field: ER ~ 17 MV/m • ring bending radius : RB ~ 25 m • BNL proposal: two beams, • (approved) simultaneously • rotating in the same • radial electric field: • cw and ccw • ring circumference: • ~ 240 m Courtesy: Storage Ring EDM Collaboration http://www.bnl.gov/edm

17. EDM at COSY – Method (III) Deuteron: (a = - 0.14) No „magic“ momentum!  combination of a dipole B-Feld and a radial E-Feld such, that the increased orbit compensates the trailing spin relative to the momentum:

18. EDM at COSY – Options Magic pEDM Ring with RB = 25 m  the size of such a ring would be larger than COSY ! No magic pEDM  the size of such a ring would be similar to COSY

19. EDM at COSY – Options 3.  the size of such a ring would easily fit into center of COSY

20. EDM at COSY – Options 3.  size of ring fits into center of COSY or into existing building Furthermore: use COSY as injector and cooler

21. EDM at COSY – Precursor Experiment • First idea: use COSY-ring with a SibirianSnake: • SibirianSnake: • Spin alignmentalongmomentumdirection in opposite ring section • 1) RF fields in-front-ofandbehindthesnakegenerate M = dp x E • 2) Change of RF per turn changes • stablespinaxisby 2a • 3) A large numberofturnsleads • to a (non-) observable lossof • beam polarisation (upper • limitfor) pEDM • BUT: non-competitivelevel Sibirian Snake RF Snake RF RF Snake RF

22. EDM at COSY – Workshop

23. Summary • COSY-Jülich • … has an excitingsymmetriesandspinphysicsprogram • … preparesforwaystoproducepolarizedantiprotonbeams • … providestestbeamsfor FAIR/HESR/PANDA • … istheplacefor a (p,d3He)-EDM search • Thankyouforyourattention !