Spin Physics with Antiprotons Project X Workshop INFN-Trieste Fermilab, Nov. 07 INFN Istituto Nazionale di Fisica Nucleare Sezione di Trieste Aldo Penzo (In collaboration with Y.Onel et al., U.of Iowa) 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 Studies of basic symmetries ( CP, CPT ) Spin dependence  Polarized { gas target p beam (!?)

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/ v1 (Feb 1993) - Antiproton induced reactions, arXiv:nucl-th/ v2 (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/ v1 (Jan 2007) QCD tests Flavour, pp →  Symmetries Spectroscopy p ↑ p ↑ → l + l - X (Drell-Yan) Transversity New Physics ?

(Polarized) gas target in p Accumulator Target Density Thickness Luminosity Type [at./cm 3 ][cm; at./cm 2 ] [cm -2 s -1 ] Mol. Cluster 4x ; 3x x Atomic Beam 6x ; 6x x Storage Cell 5x ; 1x x GeV p in AP2 line 120 GeV p (8x10 12 ) on target

Polarized antiprotons?... WHY? Sharper spectroscopy selection rules Stronger QCD tests Nucleon transversity via Drell-Yan: p↑p↑→ l + l - X - q – q annihilation in ⇈ / ⇅ spin states Many theory/phenomenology papers, see: S. Brodsky, E. Leader, J. Ellis, J-M. Richard, … Polarized target – single spin A N measurements - spin correlations in pp →  Impressive effort (PAX at FAIR, GSI) for pol. p : huge investment (>10 2 M€ ), long-range project (> 2014)

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 ??? Experimental proof Technical tests AHWD: p → (  o ) → p ↑ (2 x 10 5 p ↑ / prim. p) APES: p → p (p) → p ↑ (p) (2 x 10 3 p ↑ / prim. p) Workshop (29-31 Aug 2007) at Cockcroft Institute, Daresbury Lab, UK (mainly spin filter)

AHWD vs APES p → p2x p → (  o ) → p ↑ 2x10 -7 ~ 0.45 p → p (p) → p ↑ (p) 4x10 -9 ~ 0.30 p/p FM = I * P 2 Spin Filter – Spin Splitter More speculative methods to produce p↑: Spin filter: differential absorption of p spin states ( IF  ⇈ ≠  ⇅ ); polarized storage cell Spin splitter: Stern–Gerlach separation of p spin states; spin rotator+2 quadrupoles SF tested with protons (P ~ 0.04, I/I o ~ 0.1); but p ??? If SS tested with protons, p OK Spin Filter – baseline for GSI

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)

Benchmark processes ** q q e+e+ e-e- q q s s g ≈ cm 2 (4 ≤ M ≤ 9 GeV) ≈ cm 2  A DY ≈ ± 0.10 (T= 10 7 s)  A  ≈ ± 0.04 (T= 10 7 s) From MI (40GeV) to p accumulator (8GeV)+(pol.)H target [L ≈ x10 10 x ≈ 6x10 29 cm -2 s -1, P B ≈ 0.45, P T ≈0.8]

Throw in numbers… Consider p → (  o ) → p ↑ in 2 cases: - From MI (40GeV) to p accumulator (8GeV)+(pol.)H gas target [L ≈ x10 10 x ≈ 6x10 29 cm -2 s -1, P B ≈ 0.45, P T ≈0.8] - From SY (120 GeV) to sec. line (30GeV p)+pol. target (NH 3 ) [L ≈ 2x10 6 x3x6x10 23 ≈ 6x10 30 cm -2 s -1, P B ≈ 0.45, P T ≈0.2] Asymmetry error is  A ≈ 1/(P B P T  Nev) For p↑p↑→ l + l - X (D-Y), ≈ cm 2 (4 ≤ M ≤ 9 GeV) In a period of 10 7 s,  A DY ≈ 1/(0.45x0.8x25) ≈ ± 0.10 and  A DY ≈ 1/(0.45x0.2x77) ≈ ± 0.14 for the 2 cases respectively. For p↑p↑→  o  o X, ≈ cm 2 ; in a period of 10 5 s  A  ≈ 1/(0.45x0.8x230) ≈ ± 0.01 and  A  ≈ ± If the hyperons’ spin are analyzed,  C  ≈ 1/(0.45x0.2x0.36x230) ≈ ± 0.04, and the same for the second case. … close to ballpark…?! Back-up slide