The PAX Project and HEPI TSU Contribution 06 August, GGSWBS’12, Tbilisi. Mirian Tabidze High Energy Physic Institute of TSU

Hadron Physics Understanding of all matter comprised of quarks and gluons Understanding of all matter comprised of quarks and gluons

Mirian Tabidze HEPI TSU3 Introduction: Quark distributions Very well known q(x) = q + (x) + q-(x) Well known Δ q(x) = q + (x) - q-(x) Largely unknown Chirality Odd nature Mirian Tabidze HEPI TSU Soffer inequality: q(x) + Δq(x) ≥ 2|δq(x)|

Mirian Tabidze HEPI TSU4 Proton Spin

Mirian Tabidze HEPI TSU5 Introduction: Drell Yan Double transverse spin asymmetry Interaction between quark and antiquark Direct access to “transversity“ in Drell Yan Mirian Tabidze HEPI TSU

PAX DETECTOR: Artists view Mirian Tabidze HEPI TSU6

Drell-Yan signal and background * Mirian Tabidze HEPI TSU7

8 Polarisation For an ensemble of spin ½ particles with projections + () and – () Mirian Tabidze HEPI TSU σ(↑↑) ≠ σ(↑↓)

Mirian Tabidze HEPI TSU9 Spin Flip Polarised positron beam Un-polarised anti-proton beam Polarised anti- proton beam Spin transfer Velocity mismatch  v/c ~ Idea: How to check this idea with the existing experimental facilities? Do polarised electrons (positrons) polarise a proton (anti-proton) beam ? Mirian Tabidze HEPI TSU

10 Spin Flip: Depolarisation study at COSY p T p = 49 MeV COSY e-cooler ANKE cluster target & STT Use (transversely) polarised proton beam circulating in COSY Switch on electron cooler to depolarise proton beam Analyze proton polarisation with internal D 2 -cluster target of ANKE circumference 184 m Mirian Tabidze HEPI TSU

11 Spin Flip: Depolarisation study at COSY pd elastic scattering: detection in two (L-R) symmetric Silicon Tracking Telescopes Deuteron identification d p Mirian Tabidze HEPI TSU

12 Spin Flip: Depolarisation study at COSY Ratio of beam polarisations with and without electron beam during interaction cycles: Upper limit for longitudinal and transverse spin-flip cross section: Cross section much too small to be a useful method ! D.Oellers et al., Physics Letters B 674 (2009) 269 Mirian Tabidze HEPI TSU b

Mirian Tabidze HEPI TSU13 Spin Filtering Unpolarised anti-p beam Polarised target P beam polarization Q target polarization k || beam direction σ tot = σ 0 + σ 1 ·P·Q + σ 2 ·(P·k)(Q·k) Transverse case: Longitudinal case: For initially equally populated spin states:  (m=+½) and  (m=-½) Mirian Tabidze HEPI TSU

14 Spin Filtering Unpolarised anti-p beam Polarised target P beam polarization Q target polarization k || beam direction σ tot = σ 0 + σ 1 ·P·Q + σ 2 ·(P·k)(Q·k) Transverse case: Longitudinal case: For initially equally populated spin states:  (m=+½) and  (m=-½) Mirian Tabidze HEPI TSU

15 Spin Filtering Polarised anti-p beam Polarised target P beam polarization Q target polarization k || beam direction σ tot = σ 0 + σ 1 ·P·Q + σ 2 ·(P·k)(Q·k) Transverse case: Longitudinal case: For initially equally populated spin states:  (m=+½) and  (m=-½) Mirian Tabidze HEPI TSU

16 ANKE TOF WASA PAX COSY e-cooler Spin Filtering: PAX at COSY Low-ß section: - Quadrupoles - ABS (SC, BRP) Mirian Tabidze HEPI TSU

Skeleton view of new detector setup for SF Mirian Tabidze HEPI TSU17

Mirian Tabidze HEPI TSU18

Mirian Tabidze HEPI TSU19Mirian Tabidze HEPI TSU PAX Georgian Participants HEPI TSU Bagdasarian Zara (PhD), Lomidze Nodar, Mchedlishvili David (PhD), Nioradze Mikheil, Tabidze Mirian. IKP Jülich Kacharava Andro, Chiladze David (PosDoc). JINR Dubna Macharashvili Gogi.

Mirian Tabidze HEPI TSU20 Summary Outstanding physics potential of polarized antiprotons Very small cross-section for Spin Flip Spin Filtering seems to be the only way Investigations on Spin Filtering at COSY with transversely polarized target was done successfully (August 2011). Next step spin filtering at COSY with longitudinally polarized target (2014/2015). Next: Design of Antiproton Polariser Ring (APR?). Finally: asymmetric p-pbar collider ( GeV/c) at FAIR.

Simulation results of SF Mirian Tabidze HEPI TSU21