06 August GGSWBS12 Tbilisi Mirian Tabidze High Energy Physic Institute of TSU Hadron Physics Understanding of all matter comprised of quarks and gluons Mirian Tabidze HEPI TSU ID: 368635
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Slide1
The PAX Project and HEPI TSU Contribution
06 August, GGSWBS’12, Tbilisi.
Mirian
Tabidze High Energy Physic Institute of TSU Slide2
Hadron Physics
Understanding of all matter
comprised of quarks and gluonsSlide3
Mirian Tabidze HEPI TSU
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Introduction:
Quark distributions
Very well known
q(x) = q
+
(x) + q-(x)
Well known
Δ
q(x) = q
+
(x) - q-(x)
Largely unknown
Chirality Odd nature
Mirian Tabidze HEPI TSU
Soffer inequality: q(x) +
Δ
q(x) ≥ 2|
δ
q(x)|Slide4
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Mirian Tabidze HEPI TSU
Proton SpinSlide5
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Introduction:
Drell YanDouble transverse spin asymmetry
Interaction between
quark and antiquark
Direct access to
“transversity“
in Drell Yan
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PAX DETECTOR: Artists view
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6Slide7
Drell-Yan signal and background
*Mirian Tabidze HEPI TSU
7Slide8
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Polarisation
For an ensemble of spin ½
particles
with projections
+
() and – ()
Mirian Tabidze HEPI TSU
σ
(↑↑) ≠
σ
(↑↓)Slide9
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Spin Flip
Polarised
positron beam
Un-polarised
anti-proton beam
Polarised
anti-proton beam
Spin transfer
Velocity mismatch
D
v/c ~ 0.002
Idea:
How to check this idea with the
existing
experimental facilities?
Do polarised electrons (
positrons
) polarise a proton (
anti-proton
) beam ?
Mirian Tabidze HEPI TSUSlide10
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Spin Flip:
Depolarisation study at COSY
p
T
p
= 49 MeV
COSY
e-cooler
ANKE cluster target & STT
Use
(transversely) polarised
proton beam circulating in COSY
Switch on
electron cooler
to depolarise proton beam
Analyze
proton polarisation
with internal D
2
-cluster target of ANKE
circumference 184 m
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Spin Flip:
Depolarisation study at COSY
pd elastic
scattering:
detection in two (L-R) symmetric Silicon Tracking Telescopes
Deuteron identification
d
p
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Spin Flip:
Depolarisation study at COSY
Ratio of beam polarisations with
and without electron beam during
interaction cycles:
Upper limit for
longitudinal and transverse
spin-flip cross section:
Cross section
much too small
to be a useful method !
D.Oellers et al., Physics Letters B 674 (2009) 269
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10
13
bSlide13
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Spin Filtering
Unpolarised anti-p beam
Polarised target
P beam polarization
Q target polarization
k || beam direction
σ
tot
=
σ
0
+
σ
1
·
P
·
Q
+
σ
2
·(
P
·k)(
Q
·k)
Transverse
case:
Longitudinal
case:
For initially equally populated spin states:
(
m=+½) and
(m=-½)
Mirian Tabidze HEPI TSUSlide14
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Spin Filtering
Unpolarised anti-p beam
Polarised target
P beam polarization
Q target polarization
k || beam direction
σ
tot
=
σ
0
+
σ
1
·
P
·
Q
+
σ
2
·(
P
·k)(
Q
·k)
Transverse
case:
Longitudinal
case:
For initially equally populated spin states:
(
m=+½) and
(m=-½)
Mirian Tabidze HEPI TSUSlide15
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Spin Filtering
Polarised anti-p beam
Polarised target
P beam polarization
Q target polarization
k || beam direction
σ
tot
=
σ
0
+
σ
1
·
P
·
Q
+
σ
2
·(
P
·k)(
Q
·k)
Transverse
case:
Longitudinal
case:
For initially equally populated spin states:
(
m=+½) and
(m=-½)
Mirian Tabidze HEPI TSUSlide16
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ANKE
TOF
WASA
PAX
COSY
e-cooler
Spin Filtering:
PAX at COSY
Low-ß section:
Quadrupoles
ABS (SC, BRP)
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Skeleton view of new detector setup for SF
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17Slide18
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18Slide19
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Mirian Tabidze HEPI TSU
PAX Georgian Participants
HEPI TSU
Bagdasarian
Zara (PhD),
Lomidze
Nodar
,
Mchedlishvili
David (PhD), Nioradze Mikheil, Tabidze Mirian.IKP Jülich Kacharava Andro, Chiladze
David (PosDoc).JINR Dubna Macharashvili Gogi. Slide20
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Summary
Outstanding physics potential of polarized antiprotonsVery small cross-section for Spin FlipSpin Filtering seems to be the only wayInvestigations on Spin Filtering at COSY with transversely polarized target was done successfully (August 2011). Next step spin filtering at COSY with longitudinally polarized target (2014/2015).Next: Design of Antiproton Polariser Ring (APR?).Finally: asymmetric p-
pbar
collider (3.5-15
GeV
/c) at FAIR.Slide21
Simulation results of SF
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