Marco Maggiora Dip. “A. Avogadro” – Università e INFN - Torino Commissione I — Roma, 17-18 Maggio 2004 ASSIA LOI v Laboratory of Nuclear Problems, JINR - Dubna, Russia ento di Fisica “A. Avogadro” e INFN – Torino, Italy ento di Fisica Teorica e INFN – Torino, Italy tà e INFN – Brescia, Italy tà del Piemonte Orientale – Italy chnical University – Prague, Czech Republic CEN – Saclay, France Scientific Instruments Academy of Sciences – Brno, Czech Republic kov Physical Technical Institute – Kharkov, Ukraine ri Nazionali Frascati, INFN – Frascati, Italy tà dell’Insubria e INFN – Como, Italy tà e INFN – Trieste, Italy
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Marco Maggiora Dip. “A. Avogadro” – Università e INFN - Torino
Commissione I — Roma, 17-18 Maggio 2004. ASSIA LOI. Marco Maggiora Dip. “A. Avogadro” – Università e INFN - Torino. Dzhelepov Laboratory of Nuclear Problems, JINR - Dubna, Russia Dipartimento di Fisica “A. Avogadro” e INFN – Torino, Italy - PowerPoint PPT Presentation
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Marco MaggioraDip. “A. Avogadro” – Università e INFN -
Torino
Commissione I — Roma, 17-18 Maggio 2004
ASSIA LOI
Dzhelepov Laboratory of Nuclear Problems, JINR - Dubna, RussiaDipartimento di Fisica “A. Avogadro” e INFN – Torino, ItalyDipartimento di Fisica Teorica e INFN – Torino, ItalyUniversità e INFN – Brescia, ItalyUniversità del Piemonte Orientale – ItalyCzech Technical University – Prague, Czech RepublicDAPNIA, CEN – Saclay, FranceInst. of Scientific Instruments Academy of Sciences – Brno, Czech RepublicNSC Kharkov Physical Technical Institute – Kharkov, UkraineLaboratori Nazionali Frascati, INFN – Frascati, ItalyUniversità dell’Insubria e INFN – Como, ItalyUniversità e INFN – Trieste, Italy
Introduction
• SIS300 @ GSI:
• A complete description of nucleonic structure requires:
@ leading twist and @ NLO
• Physics objectives:
Drell-Yan di-lepton production
spin observables in hadron production
electromagnetic form factors
proton and gluon distribution functions
quark fragmentation functions
fm104λGeV/c40,p 2
pP
f1, g1 studied for decades: h1 essentially unknown
)kx,(fkd)x(f T1T2
1
Twist-2 PDFs
κT-dependent Parton Distributions
Distribution functions
Chirality
even odd
Twist-2
U
L
T
f1
g1
, h1,
h1
h1L
h1T
f 1T
g1T
Kinematics
Why Drell-Yan?
Asymmetries depend on PD only (SIDIS→convolution with QFF)
Why ?
Each valence quark can contribuite to the diagram
Drell-Yan Di-Lepton Production Xμμpp
p
q2P
Mx
1
2
1
xxx 21F
q2P
Mx
2
2
2
s
Mτ
2
21xx
0QM 22μμ
Scaling:
Full x1,x2 range .
needed
[1] Anassontzis et al., Phys. Rew. D38 (1988) 1377
NH3 10g/cm3 : 2 x 10cm cells with opposite polarisation
GSI modifications:• extraction SIS100 → SIS300 or injection CR → SIS300 • slow extraction SIS300 → beamline adapted to • experimental area adapted to handle expected radiation from
GeV40Ep
17
3f 85.0PT
1231723 sm105.1105.11061017
3L
sp102 7
Beam and Target
TARGET COMPASS likeTransverse and longitudinal polarisation
BEAM high luminosity and intensity Eventually polarised -beam from SIS300
UNIQUE TOOL TO INVESTIGATENUCLEON STRUCTURE
pp
Alternative GSI solution
• Luminosity comparable to external target → KEY IUSSUE • dilution factor f~1• difficult to achieve polarisation Pp ~ 0.85• required achievable with present HESR performances (15 GeV/c)• only transverse asymmetries can be measured• p↑-beam required polarisation proton source and acceleration scheme preserving polarisation• no additional beam extraction lines needed• EXPERIMENTAL SETUP COMPLETELY DIFFERENT
HESR collider polarised p and beams p
s
GeV/c15 Pp
Experimental setup
Possible setup scheme similar to the COMPASS first spectrometer
• SM1 magnet ( 1Tm, stands )
• GEM,MICROMEGA detetors smaller angle
• MWPC, STRAW detectors larger angle
• expected resolution
• vertex resolution
• HODOSCOPEs → Trigger
• sandwiches iron plates, Iarocci tubes, scintillator slabs → Id
• beam vacuum pipe along the apparatus
/sp101.5 7
μm 70σ
mm 1.5σ , 2MeV/c 2.5σ
cm 1 mm 2σ
Main goal: spin physics nucleon structure DY di-lepton production distribution functions Spin observables in hadron production fragmentation Electromagnetic form factors