Spin Physics with Antiprotons

1
Spin Physics with Antiprotons
2
Spin Physics with p(Some References)

• S. Brodsky - Testing QCD in Antiproton Reactions,
• SLAC-PUB-4451 (Oct
  1987)
• J-M. Richard - Spin and Flavour,
• arXivnucl-th/93020
  03v1 (Feb 1993)
• - Antiproton induced
  reactions,
• 
  arXivnucl-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,
• arXivhep-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 lt P
  gt
• Type at./cm3 cm at./cm2 cm-2 s-1
• Mol. Cluster 4x1014 0.7 3x1014
  2x1032 0.0
• Atomic Beam 6x1011 1.0 6x1011 4x1029
  0.9
• Storage Cell 5x1012 20. 1x1014
  7x1031 0.8

4
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
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
AHWD vs APES
FM I P2

• 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
Benchmark processes
ltsAgt 10-34 cm2 (4 M 9 GeV)
ltsAgt 10-30 cm2
9
Throw in numbers
Back-up slide

• 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), ltsAgt 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?? Lo Lo X, ltsAgt 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