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Spin Physics with Antiprotons

FNAL Antiproton Accumulator • world record p stacking rate ( ≈ 2 ×10 11 /hr ) • jet target experiments E760/E835 (<2000) L ≈ 2 ×10 31 cm - 2 s - 1 ( → 2 ×10 32 cm -2 s -1 ) • Precision QCD tests and spectroscopy • Physics of Flavour Studies

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Spin Physics with Antiprotons

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  1. FNAL Antiproton Accumulator • world record pstacking rate (≈ 2 ×1011/hr) • jet target experiments E760/E835 (<2000) L ≈ 2 ×1031cm-2 s-1 (→ 2 ×1032cm-2 s-1 ) • PrecisionQCDtests and spectroscopy • Physics ofFlavourStudies • Studies of basic symmetries (CP, CPT) • Spindependence  Polarized { gas target p beam (!?) (In collaboration with Y.Onel et al., U.of Iowa) Aldo Penzo Project X WorkshopINFN-Trieste Istituto Nazionale di Fisica Nucleare INFN Fermilab, Nov. 07 Sezione di Trieste Spin Physics with Antiprotons

  2. QCD tests Flavour, pp → LL Symmetries Spectroscopy p↑p↑→ l+ l- X (Drell-Yan) Transversity New Physics ? Spin Physics with p(Some References) • S. Brodsky -Testing QCD in Antiproton Reactions, SLAC-PUB-4451 (Oct 1987) • J-M. Richard -Spin and Flavour, arXiv:nucl-th/9302003v1 (Feb 1993) - Antiproton induced reactions, arXiv:nucl-th/9406025v2 (Jul 1994) • W.A. Mok, K.J. Sebastian -Charmonium states in polarized p-pbar collisions, N. Cim. A110, 429 (1997) • V. Barone, A. Drago and P. Ratcliffe – Phys. Rep. 359, 1 (2002) • M.Anselmino et al. - Phys.Lett. B594, 97 (2004) • R. Jaffe -Open questions in high-energy spin physics, MIT-CTP-3230 (Jan 2002) • J. Ellis -Polarization puts a New Spin on Physics, arXiv:hep-ph/0701049v1 (Jan 2007)

  3. (Polarized) gas target in p Accumulator • 8 GeV p in AP2 line • 120 GeV p (8x1012) on target • Target Density Thickness Luminosity < P > Type [at./cm3] [cm; at./cm2] [cm-2 s-1] • Mol. Cluster 4x1014 0.7; 3x1014 2x1032 0.0 • Atomic Beam 6x10111.0; 6x10114x1029 0.9 • Storage Cell 5x1012 20.; 1x10147x1031 0.8

  4. Polarized target – single spin AN measurements - spin correlations in pp → LL -q – qannihilation in⇈/⇅spin states Impressive effort (PAX at FAIR, GSI) for pol. p : huge investment (>102 M€ ), long-range project (> 2014) Polarized antiprotons? ... WHY? • Sharper spectroscopy selection rules • Stronger QCD tests • Nucleon transversity via Drell-Yan:p↑p↑→ l+ l- X Many theory/phenomenology papers, see: S. Brodsky, E. Leader, J. Ellis, J-M. Richard, …

  5. Experimental proof Technical tests AHWD:p → (Lo) → p↑ (2 x 105 p↑/ 1012 prim. p) APES:p → p (p) → p↑(p) (2 x 103 p↑/ 1012 prim. p) Polarized Antiprotons: HOW? Workshop on Polarized Antiproton Sources Bodega Bay CA, April 1985; O. Chamberlain, A. Krisch, A. Lin • Antihyperon Decay • Spin Filter • Stochastic Tecniques • Dynamic Nuclear Polarization • Syncrotron Radiation emission • Antiproton Scattering • Repeated Stern-Gerlach • Antihydrogen formation • Penning trap • Channeling • ...........??? Workshop (29-31 Aug 2007) at Cockcroft Institute, Daresbury Lab, UK (mainly spin filter)

  6. p/p <P> More speculative methods to produce p↑: • Spin filter:differential absorption of p spin states (IF s⇈≠s⇅); polarized storage cell • Spin splitter:Stern–Gerlach separation of p spin states; spin rotator+2 quadrupoles SF tested with protons (P ~ 0.04, I/Io ~ 0.1); but p ??? If SS tested with protons, p OK FM = I*P2 AHWD vs APES • p → p 2x10-5 0.0 • p → (Lo) → p↑ 2x10-7 ~ 0.45 • p → p (p) → p↑(p) 4x10-9 ~ 0.30 Spin Filter – Spin Splitter Spin Filter – baseline for GSI

  7. Prospects for p spin physics Medium term: • FNAL Antiproton Source survive collider era: • Challenging, fresh physics! • Moderate cost upgrades? • Polarized gas target to complement E835 jet • AHWD secondary beam (~ 8 GeV) from Main Injector (40 GeV) to antiproton accumulator? Longer term: • Tests of Spin Filter/Splitter in Accumulator Ring (+ gas target)

  8. g* q e+ s q g e- q s q dADY ≈ ± 0.10 (T= 107 s) dALL ≈ ± 0.04 (T= 107 s) From MI (40GeV) to p accumulator (8GeV)+(pol.)H target [L ≈ 1014x1010x6.105 ≈ 6x1029 cm-2 s-1, PB ≈ 0.45, PT ≈0.8] Benchmark processes <sA> ≈ 10-34 cm2 (4 ≤ M ≤ 9 GeV) <sA> ≈ 10-30 cm2

  9. Back-up slide Throw in numbers… Consider p → (Lo) → p↑in 2 cases: - From MI (40GeV) to p accumulator (8GeV)+(pol.)H gas target [L ≈ 1014x1010x6.105 ≈ 6x1029 cm-2 s-1, PB ≈ 0.45, PT ≈0.8] - From SY (120 GeV) to sec. line (30GeV p)+pol. target (NH3) [L ≈ 2x106x3x6x1023 ≈ 6x1030 cm-2 s-1, PB ≈ 0.45, PT ≈0.2] Asymmetry error is dA ≈ 1/(PB PTNev) For p↑p↑→ l+ l- X (D-Y), <sA> ≈ 10-34 cm2 (4 ≤ M ≤ 9 GeV) In a period of 107 s, dADY ≈ 1/(0.45x0.8x25) ≈ ± 0.10 and dADY ≈ 1/(0.45x0.2x77) ≈ ± 0.14 for the 2 cases respectively. For p↑p↑→ LoLo X,<sA> ≈ 10-30 cm2 ; in a period of 105 s dALL ≈ 1/(0.45x0.8x230) ≈ ± 0.01 and dALL ≈ ± 0.02. If the hyperons’ spin are analyzed, dCLL ≈ 1/(0.45x0.2x0.36x230) ≈ ± 0.04, and the same for the second case. … close to ballpark…?! Back-up slide

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