MENU2004, Bejing, August 29- September 5, 2004 Raimondo Bertini Dipartimento di Fisica ``A. Avogadro'' and INFN - Torino, Italy Λ POLARISATION TO PROBE N STRUCTURE

 polarisation in inclusive hadron production strong p T dependence: increase with p T up to ~1GeV/c, then constant strong x F dependence: near with x F linear increase of Transverse polarisation, normal to the production plane [1] [1] L. G. Pondrom, Phys. Rep. 122(1985)57

polarisation magnitude indipendent of beam energy  polarisation in inclusive hadron production Transverse polarisation, normal to the production plane [1] [1] L. G. Pondrom, Phys. Rep. 122(1985)57

polarisation transfer: TFR CFR

Hyperon production Spin Asymmetries  production in unpolarised pp-collision: Several theoretical models: Static SU(6) + spin dependence in parton fragmentation/recombination [1-3] pQCD spin and transverse momentum of hadrons in fragmentation [4] [1] T.A.DeGrand et al.,Phys. Rev D23 (1981) [2] B. Andersoon et al., Phys. Lett. B85 (1979) 417. [3] W.G.D.Dharmaratna, Phys. Rev. D41 (1990) [4] M. Anselmino et al.,Phys. Rev. D63 (2001) Analysing power Depolarisation Key to distinguish between these models Data available for D NN : 3.67 GeV/c D NN < GeV/c D NN ~ GeV/c D NN > 0 D 40 GeV/c MISSING

f 1, g 1 studied for decades: h 1 essentially unknown Twist-2 PDFs κ T -dependent Parton Distributions Distribution functions Chirality even odd Twist-2 ULTULT f 1 g 1,h1,h1,

Λ polarisation with longitudinally polarised lepton beam along ê³

Unpolarised beam and longitudinally pol. target Transverselly polarised target

Assuming u-quark dominance R. L. Jaffe Phys. Rev. D54 (1996) R6581

Semi-inclusive deep inelastic scattering

Hyperon production Spin Asymmetries Polarised target:. Transverse target polarisation Existing data: PS185 (LEAR) [2] [1] K.D. Paschke et al., Phys. Lett. B495 (2000) 49. [2] PS185 Collaboration, K.D: Paschke et al., Nucl. Phys. A692 (2001) 55. [1] complete determination of the spin structure of reaction Models account correctly for cross sections. Models do not account for or. NEW DATA NEEDED

Open charm from production and subsequent weak decay low branching ratio: B.R. = 0.9% huge self-analysing asymmetry: [1] Smith Vogt Z. Phys. C75 (1997)271 Open Charm ΔG longitudinally polarised

Beam and Target SIS 100 Tm SIS 300 Tm U: 35 AGeV p: 90 GeV Key features: Generation of intense, high-quality secondary beams of rare isotopes and antiprotons. Two rings: simultaneous beams.

Scaling: Full x 1,x 2 range. needed [1] Anassontzis et al., Phys. Rew. D38 (1988) 1377 Drell-Yan Di-Lepton Production

Kinematics Why Drell-Yan? Asymmetries depend on PD only (SIDIS→convolution with QFF) Why ? Each valence quark can contribuite to the diagram Drell-Yan Di-Lepton Production

Uncorrelated quark helicities access chirally-odd functions TRANSVERSITY Drell-Yan Asymmetries — Polarised beam and target Ideal because: h 1 not to be unfolded with fragmentation functions chirally odd functions not suppressed (like in DIS)

Drell-Yan Asymmetries — Polarised beam and target

Drell-Yan Asymmetries — Unpolarised beam, polarised target λ  1,   0 Even unpolarised beam is a powerful tool to investigate к T dependence of QDF D. Boer et al., Phys. Rev. D60(1999)

Phase space for Drell-Yan processes 30 GeV/c 15 GeV/c 40 GeV/c  = const: hyperbolae x F = const: diagonal PANDA ASSIA

Drell-Yan Asymmetries — Unpolarised beam, polarised target λ  1,   0 Even unpolarised beam is a powerful tool to investigate к T dependence of QDF D. Boer et al., Phys. Rev. D60(1999)

A. Bianconi (ASSIA col.)