SPIN PHYISICS at FAIR
F. Bradamante
J-PARC WORKSHOP, KEK
November 30, 2005
Generalized Parton Distributions
F. Bradamante
J-PARC Workshop
Sincrotrone a doppio
FAIR
anello per
• accelerare p a 28 GeV
per targhetta di
produzione
SIS18 booster per
protoni - 1 GeV
50 MeV
Proton Linac
• accelerare antip da 3
GeV per trasferirli a
HERS
• con SIS300 (anti)p a
piu’ di 40 GeV
High Energy
Sorage Ring
Collector Ring
NERS
F. Bradamante
raffreddamento
J-PARC Workshop
stocastico antip
Physics with Polarized Antiprotons at GSI
ASSIA LoI
• SIS300 @ GSI: ppbar > 40 GeV
• Physics objectives:
• Drell-Yan di-lepton production  transversity
• spin observables in hadron production
• electromagnetic form factors
PAX LoI
F. Bradamante
J-PARC Workshop
Drell-Yan Di-Lepton Production


pp  μ μ X
cinematica
M2
2P1  q
x1 
M Q 0
2
μμ
2
x  x x
F
1
x2 
M2
2P2  q
2
M2
τ  x1 x 2 
s
Drell-Yan: the asimmetries depend only on the PDF’s
in SIDIS they are convoluted with spin dependent fragmentation functions (*)
antiprotons: only valence quark contribute
in proton-proton sea quarks also
(*) only SIDIS allows for flavour separation
F. Bradamante
J-PARC Workshop
Drell-Yan Asymmetries
Beam and target polarized
g (x ) g (x )

e
A 
 e f (x ) f (x )
a
LL
a
2
a
a
a
1
2
1
a
a
1
1
1
a
2
1
2
sin θcos2φ a ea h1 ( x1) h1 ( x 2)

1  cos 2θ  2 a ( ) a ( )
2
2
A
TT
a
a
a
ef x f x
a
1
1
1
2
a
a
a
 a ( )

(
)
(
)
(
)
g
g
h

e
x
x
x
x
x
1
2
2
1
2
x
a
h
a
1
1 L
2sin2 θ cosφ M
T
 1


a
ALT 1  cos 2θ Q2
2 a
a ea f 1 (x1) f 1 (x2)
2
F. Bradamante
J-PARC Workshop
Spin Physics at FAIR
ASSIA Collaboration + Novosibirsk (Y. Shatunov et al.)
investigations of possible machine options to have polarized
proton - antiproton collisions at sufficiently high energies
• symmetric collider (15 GeV + 15 GeV)
• asymmetric collider (3.5 GeV + 3.5 GeV)
• feasibility study of part of the program at PANDA
• simulations studies for the Drell-Yan process
PAX
• apparatus studies
• studies on the polarizability of the antiprotons:
proposed measurements at COSY and at AD
work in progress towards a
Spin Experiment with AntiProtons (SEAP)
in parallelo a PANDA
F. Bradamante
J-PARC Workshop
SEAP IP
F. Bradamante
J-PARC Workshop
F. Bradamante
J-PARC Workshop
Transverse Structure Functions (Drell-Yan)
Phase space
 = const: hyperbolae
xF = const: diagonal
15 GeV/c
PANDA (GSI)
30 GeV/c
40 GeV/c
ASSIA (GSI)
COMPASS
F. Bradamante
J-PARC Workshop