close

Вход

Забыли?

вход по аккаунту

?

Презентация PowerPoint - Bogoliubov Laboratory of Theoretical

код для вставкиСкачать
STAR
10-th Workshop on High Energy Spin Physics
September 16-21, 2003, Dubna, Russia
The STAR Spin Physics Program
Sandibek B. Nurushev
Institute for High Energy Physics, Protvino,
Russia
(On behalf of the STAR Collaboration)
STAR
Contents
Introduction
The polarized RHIC Complex
STAR detector
Lessons of the first polarized beam runs
Main goals of the STAR Spin Physics Program
Hyperon polarizations
Summary
STAR
Brazil:
Universidade de Sao
Paulo
China:
IHEP - Beijing
IMP - Lanzhou
IPP - Wuhan
USTC
INR - Shanghai
Tsinghua University
Grotia:
University of Zagreb
Czech Republic:
NPI - AS CR Rez
Great Britain:
University of Birmingham
France:
IReS Strasbourg
SUBATECH - Nantes
Germany:
MPI – Munich
University of Frankfurt
India:
IOP - Bhubaneswar
Panjab University
University of Rajasthan
Jammu University
IIT - Bombay
VECC - Kolcata
Netherlands:
NIKHEF
The STAR Collaboration
~ 500 Collaborators
12 Countries
48 Institutions
Poland:
Warsaw Univ. of Tech.
Russia:
MEPHI - Moscow
LPP/LHE JINR - Dubna
IHEP - Protvino
U.S. Laboratories:
Argonne
Berkeley
Brookhaven
U.S. Universities:
Arkansas University
UC Berkeley
UC Davis
UC Los Angeles
Carnegie Mellon University
Creighton University
Indiana University
Kent State University
Michigan State University
City College of New York
Ohio State University
Penn. State University
Purdue University
Rice University
Texas A&M
UT Austin
Valparasio University
Washington University
Wayne State University
Yale University
STAR
Polarized RHIC Complex
Equipment
to be
installed
after FY03
STAR
STAR – Solenoid Tracker At RHIC
Spin
Run0
Run1
Run2 and beyond
Time Projection
Chamber |h|<1.5
Silicon Vertex
Tracker
Magnet
Coils
B=0.25T
0.5T
Forward TPCs
2.4 < |h| < 4.0
2m
Endcap EMC
1< h <2 Df = 2p
Barrel EMC
0< h< 1 Df =2p/5
4.2 m
Central Trigger
Barrel |h| < 1
|h| < 1 Df = 2p
Forward Pion Detector
(FPD) 3.1 < h < 4.4
+ upgrade
RICH: |h|<0.3, Df = p/6
О· пЂЅ пЂ­ ln[tan( Оё/2)]
18 papers in NIM A499 (2003)
Beam-Beam Counters
2 .4< |h| < 5.0
STAR
EMC
(Half)
Barrel
BBC
West
STAR upgrades for Spin
STAR
BBC
East
TPC
Forward
Pion Dets.
(L,R,U,D on
E; L,D on W)
EndCap
EMC (1/3)
STAR adding lots of EM calorimetry to detect high-energy пЃ§,
eп‚±, p0 plus Beam-Beam
Counters for relative luminosity
and polarization monitoring.
EMC’s and FPD’s partially
implemented for 2003 run, will
be completed before 2005.
BBC - luminosity monitoring detector
STAR uses observed asymmetry (AN
~0.006) in inclusive forward charged
at STAR
particle production in Beam-Beam
Fast, highly-segmented
Counters:
Top
Interaction
scintillation counter serves
Vertex
Left
many purposes in STAR:
Right
Bottom
• Minimum Bias Trigger
• Absolute Luminosity
BBC East
• Relative Luminosity
3.3<|h|< 5.0
• Measurement of Transverse
BBC West
Asymmetries
See L. Bland talk
*
STAR
Lessons of the first polarized beam runs
at пѓ– s=200 GeV
1. BBC detector. It revealed the asymmetry of
charged particles on the level ANп‚»(1В±0.2)10-3 for
each run. This is comparable to AN(CNI)
п‚»(3В±0.3)10-3 .
2. TPC. The asymmetry of the Leading Charged
Particles (LCP) is close to zero on the level
ANп‚»(1В±1)10-2 up to pT п‚»4 GeV/c for charged
particles of both signs.
3. FPD. It detected inclusive p0 asymmetry on the
level ANп‚»(0.2В±0.07) at xFп‚»0.5.
STAR
The Leading Charged Particle Asymmetry
The asymptotic quark asymmetry
Among the many complicated theoretical formulae the pQCD
prediction for asymptotic quark asymmetry (polarization) is very
simple, namely
AN пЂЅ
О±s mq pT
p пЂ«m
2
T
2
Here mq is the quark mass, m is the final hadronic mass,
pT is the transverse momentum and
О±s ( Ој ) пЂЅ
2
4ПЂ
2
ОІ 0 ln( Ој /О›
2
)
, ОІ 0 пЂЅ 11 пЂ­
2
3
n f , О› пЂЅ 0.234 GeV
where nf is the number of flavors.
STAR
The spin-orbital interaction
The soft scattering regime. It is well known from the
dawn of the Spin Physics, that the spin orbital
interaction (much smaller than the central potential)
leads to the shift of the angular distribution of the
scattered particles, so
AN пЂЅ
п‚­
п‚Ї
п‚­
п‚Ї
Пѓ (Оё)пЂ­Пѓ (Оё)
Пѓ (Оё)пЂ«Пѓ (Оё)
пЂЅ
d
(ln Пѓ ( Оё )) О” Оё
dОё
F.Halzen, Phys.Rev. 1962
STAR
The model of the quark polarization
This above expression was modified by M.G. Ryskin
(Sov. Jour. Nucl. Phys. 48 (1988) 1114).
He assumed that two quarks in the colored string
interact through the potential
VОјH
A
q
N
пЂЅ
п‚­
п‚Ї
п‚­
п‚Ї
Пѓ (Оё)пЂ­Пѓ (Оё)
Пѓ (Оё)пЂ«Пѓ (Оё)
пЂЅ
Оґp T
пЃ¶ пЃІ
пЂЅ Ој пѓ— H,
d
dОё
(ln Пѓ ( Оё ) ) пЂЅ Оґp T
пЃІ пЃІ
пЂЅ Ој пѓ— H п‚» 0.1 GeV
d
dp T
(ln Пѓ (p T ))
STAR
The inclusive pion versus quark asymmetry
A
R пЂЅ
P
q
ПЂ
N
пЂЅ Pq пѓ— A
s0
3
s(1 пЂ­ x) пЂ« s 0
пЂЅ x, the initial
p T пЂЅ 4 GeV/c,
, s
0
q
N
пѓ—R
п‚» 6 GeV
quark
2
polarizati
x T пЂЅ 0.04, m q п‚» 100 MeV, s
A N п‚» 8 пѓ— 10
1/2
on
пЂЅ 200 GeV
пЂ­3
The prediction can be verified at STAR
STAR
Global NLO QCD analysis of DIS data
SLAC (E142, E143, E154, E155)
CERN (EMC, SMC)
DESY (HERMES)
185 exp. points
A
p, n, d
1
, g
p, d
1
First moments at
Spin-dependent PDFs
Q пЂЅ 1 GeV
2
NLO QCD (JET),
P D (g 1
P D (g 1
p, d
1
N LO
N LO
2
+ HT)
/F 1
N LO
)
/F
Q2
=1
GeV2
0 .4
x ( D u + D u- )
0 .4
0 .3
0 .3
О”ОЈ пЂЅ
0.32 п‚± 0.06
О”u пЂЅ
0.84 п‚± 0.03
x D G (x )
0 .2
0 .2
0 .1
О”d пЂЅ - 0.43 п‚± 0.04
О”s пЂЅ - 0.09 п‚± 0.03
О”G пЂЅ
0.80 п‚± 0.43
0 .1
0 .0
0 .0
0 .0 1
0 .1
0 .0
О”u, О” d
not extracted
0 .1
x1
0 .0
-0 .1
-0 .2
-0 .1
x(D d + D d )
-0 .3
DG not well constrained
0 .0 1
x 1
x(D s + D s )
-0 .2
-0 .4
0 .0 1
0 .1
x
1
0 .0 1
E. Leader, A. Sidorov, D. Stamenov
Phys. Rev. D67 (2003) 074017
0 .1
x
1
STAR
Spin Physics Program at STAR
Gluon Polarization
Direct Photon + jet qg п‚® q пЃ§ QCD Compton scattering
qg п‚® Jet пЂ« Jet or gg п‚® Jet пЂ«
Jet and DiJets
Heavy flavor production (?) gg п‚® Q Q
п‚ / Anti-Quark
п‚ Quark
W п‚± production
Jet
Polarization
& Flavor Decomposition
_
qq п‚®W
п‚±
п‚® e
п‚±
Transversity & Transverse Spin Effects
Single transverse spin asymmetries
Transversity via Jet fragmentation
Transversity via Dijet or Drell-Yan pairs
New Physics ?
Parity violating asymmetries
STAR
Where is the spin
of the proton?
At present, the gluon contribution to the proton spin (DG) is known
only poorly from scaling violation in polarized deep inelastic scattering
STAR Spin goals:
determine the gluon contribution to the proton’s spin
determine the flavor decomposition of the quark (antiquark)
polarization
probe transversity: the unknown, remaining leading-twist
structure function
STAR
Parton distributions in proton
Quark chirality is conserved at all QCD and electroweak vertices, however quark
chirality can flip in distribution function because they probe the soft regime
where chiral symmetry is dynamically broken in QCD.
Helicity average probes quark-gluon mixing q & G
q &G
Probability density to find quarks in nucleon moving in the z direction
qпЂЅq
п‚®
п‚®
пЂ«q

п‚®
G пЂЅG
п‚®
п‚®
пЂ«G

п‚®
x
helicity average
z
y
Helicity probes quark-gluon mixing Dq & DG
Dq & DG Probability to find longitudinal (z direction) polarized quarks & gluons
in longitudinal polarized nucleon moving in the z direction.
п‚®

О”q пЂЅ q п‚® пЂ­ q п‚®
п‚®

О”G пЂЅ G п‚® пЂ­ G п‚®
helicity difference
Transversity probes dynamical chiral symmetry breaking
dq Probability to find transversely (x direction) polarized quarks in transversely
polarized nucleon moving in the z direction.
п‚­
п‚Ї
Оґq пЂЅ q п‚­ пЂ­ q п‚­
helicity flip
STAR
ALL(ПЂ0) Measurements at E704
A.Bazilevsky
ПЂ0 ALL from pp at s 1/2 =20 GeV
E704
The two-spin parameter ALL in inclusive ПЂ0 production by longitudinally-polarized
protons and antiprotons on a longitudinally-polarized proton target has been measured
at 200 GeV Fermilab spin physics facility, for π0�s at xF =0 with 1 ≤ pt ≤ 3 GeV/c. The
results exclude, at 95% confidence level, values of ALL(pp)>0.1 and < − 0.1, for π0�s
produced by protons, and values of ALL(pp)>0.1 and < в€’ 0.2 for incident antiprotons.
The data are in good agreement with “conventional”, small or zero, gluon polarization.
STAR
ALL(nОі) Measurements at E704
The double-spin asymmetry, ALL, for inclusive multi-Оі pair production was
measured with a 200 GeV/c longitudinally-polarized proton beam and a
longitudinally-polarized proton target. The ALL values were found to be
consistent with zero. The ALL values have been compared with theoretical
predictions of gluon polarization, О”G/G. The results put restrictions on the
size of О”G/G in the region of 0.05<x<0.35.
STAR
STAR spin goals
пЃІ пЃІ
p пЂ« p п‚® jet пЂ« X
Measure of double-spin asymmetry ALL
with longitudinally polarized protons
Jet, di-jet production
A LL пЂЅ
1
N
P1 P2 N
п‚Їп‚­
п‚Їп‚­
пЂ­ RN
п‚­п‚­
пЂ« RN
п‚­п‚­
пЃІ пЃІ
p пЂ« p п‚® jet пЂ« jet пЂ« X
R пЂЅ
L
L
п‚Їп‚­
п‚­п‚­
N – spin dep.yields of process
L – yields of luminosity
monitoring process
R – relative luminosity
P – beam polarization
Gluon spin-dependent distribution
function
Gluon contribution to proton spin
Sign of DG
A LL пЂЅ
Пѓ
п‚Їп‚­
Пѓ
п‚Їп‚­
пЂ­Пѓ
п‚­п‚­
пЂ«Пѓ
п‚­п‚­
п‚µ
О”G(x 1 )
G(x 1 )

e
2
e i О”q i (x 2 )
2
i
q i (x 2 )
a LL (gq п‚® gq)
“ ..A priori not even the sign of Г is known, and it may be negative.”
R.L.Jaffe
STAR
STAR spin goals
пЃІ пЃІ
p пЂ« p п‚® Оі пЂ« jet пЂ« X
пЃІ пЃІ
pпЂ«pп‚® ОіпЂ«X
Measure of double-spin asymmetry ALL
with longitudinally polarized protons
Direct пЃ§ production
пЃ§ пЂ«jet correlation
A LL пЂЅ
1
N
P1 P2 N
п‚Їп‚­
п‚Їп‚­
пЂ­ RN
п‚­п‚­
пЂ« RN
п‚­п‚­
L
R пЂЅ
L
п‚Їп‚­
п‚­п‚­
N – spin dep.yields of process
L – yields of luminosity
monitoring process
R – relative luminosity
P – beam polarization
Gluon spin-dependent distribution
function
Gluon contribution to proton spin
Sign of DG
1
пЂЅ
2
О”ОЈ пЂј 1
О”s пЂј 0
A LL пЂЅ
1
2
Пѓ
п‚Їп‚­
Пѓ
п‚Їп‚­
О”ОЈ пЂЅ О”u пЂ« О”d пЂ« О”s
О”ОЈ пЂ« О”G пЂ« L z пЂ« L z
q
пЂ­Пѓ
п‚­п‚­
пЂ«Пѓ
п‚­п‚­
п‚µ
О”G(x 1 )
G(x 1 )
g

e
2
e i О”q i (x 2 )
2
i
q i (x 2 )
a LL (gq п‚® Оіq)
STAR
STAR Spin Goals
пЃІ
п‚±
pпЂ«pп‚®W пЂ«X
Measure of parity violating asymmetry AL
with longitudinally polarized protons
W
п‚±
AL пЂЅ
selects spin and flavour
п‚­
п‚Ї
п‚­
п‚Ї
1 N пЂ­ RN
P N пЂ« RN
R пЂЅ
L
L
п‚­
п‚Ї
N – spin dep.yelds of process
L – yields of luminosity
monitoring process
R – relative luminosity
P – beam polarization
Separate quark - Du, Dd , antiquark
Du,
d helicity distribution functions
ВЇ DВЇ
пЂў
пЂў
A
A
W
L
W
L
пЂ«
пЂ­
пЂЅ
пЂЅ
О”u(x 1 ) d (x 2 ) пЂ­ О” d (x 1 )u(x 2 )
u(x 1 ) d (x 2 ) пЂ« d (x 1 )u(x 2 )
О”d(x 1 ) u (x 2 ) пЂ­ О” u (x 1 )d(x 2 )
d(x 1 ) u (x 2 ) пЂ« u (x 1 )d(x 2 )
x 1 пЂѕпЂѕ x 2
x 1 пЂјпЂј x 2
x 1 пЂѕпЂѕ x 2
x 1 пЂјпЂј x 2
О”u(x 1 )
u(x 1 )
пЂ­
О” d (x 1 )
d (x 1 )
О”d(x 1 )
пЂ­
d(x 1 )
О” u (x 1 )
u (x 1 )
STAR
STAR Spin Goals
Transverse single pion asymmetry AN
from E704 to STAR
0.5 пЂј p T пЂј 2.0 GeV/c
FNAL
AN пЂЅ
p пЂ«pп‚®ПЂ
п‚­
п‚± ,0
пЂ«X
ПѓL пЂ­ ПѓR
ПѓL пЂ« ПѓR
пЂ­
s пЂЅ 20 GeV
p
AN increases with xF and reaches 40%
AN ≈ 0 at xF ≈ 0
sign(AN) – charge(p) correlation
AN (pp) ≈ – AN (pp)
_
AN пЂЅ
в—Џ
в—Џ
p0 - D.L. Adams, et al., Phys. Lett. B261(1991)201.
p+/- - D.L. Adams, et al., Phys. Lett. B264(1991)462.
1
PB
пѓ—
п‚­
п‚Ї
п‚­
п‚Ї
p
R L пЂ­
R L пЂ«
п‚Ї
п‚­
п‚Ї
п‚­
R L
R L
STAR
STAR Spin Goals
Measure of double-spin
longitudinal ALL and transverse ATT
asymmetry for Drell-Yan pair production
пЃІ пЃІ
пЂ« пЂ­
pпЂ«pп‚®l l пЂ«X
Longitudinally polarized density Dq
A LL пЂЅ
Пѓ
п‚Їп‚­
Пѓ
п‚Їп‚­
пЂ­Пѓ
п‚­п‚­
пЂ«Пѓ
п‚­п‚­

e
e i [ О”q i (x 1 , Q ) D q i (x 2 , Q ) пЂ« (1 п‚« 2)]
2
п‚µ
2
2
i
2
[q i (x 1 , Q ) q i (x 2 , Q ) пЂ« (1 п‚« 2)]
2
2
a LL
Transverse polarized density dq
A TT пЂЅ
Пѓ
п‚Їп‚­
Пѓ
п‚Їп‚­
пЂ­Пѓ
п‚­п‚­
пЂ«Пѓ
п‚­п‚­
п‚µ
 e [ δq
 e [q
2
i
2
i
i
(x 1 , Q )Оґ q i (x 2 , Q ) пЂ« (1 п‚« 2)]
i
(x 1 , Q ) q i (x 2 , Q ) пЂ« (1 п‚« 2)]
2
2
2
2
пЂ« пЂ­
pп‚­ пЂ« pп‚­ п‚® l l пЂ« X
a TT
Transversity distributions can not be measured in conventional DIS,
semi-inclusive DIS is required. Transversity distributions are prime
candidates for experiments at polarized proton collider.
STAR
STAR Spin Goals
Measure of spin-transfer asymmetry A
О›
A пЂЅ
О›( пЂ« )
пЂ« ПѓпЂ­
О›( пЂ« )
пЂ« ПѓпЂ­
(Пѓ пЂ«
(Пѓ пЂ«
О›( пЂ­ )
) пЂ­ (Пѓ пЂ«
О›( пЂ­ )
) пЂ« (Пѓ пЂ«
Spin-dependent fragmentation function
О”D
О›
i
О›( пЂ« )
О›( пЂ­ )
(z) п‚є D i( пЂ« ) (z) пЂ­ D i( пЂ« ) (z)
О›( пЂ­ )
пЂ« ПѓпЂ­
О›( пЂ« )
О›( пЂ­ )
пЂ« ПѓпЂ­
О›( пЂ« )
О›
пЃІ
пЃІ
pпЂ«pп‚®О›пЂ«X
)
)
describes the transformation of
a longitudinal polarized parton into
a longitudinal polarized L
Sensitivity to flavour
Phenomena exist but
polarization transfer.
Negative s (1), (u+d) (2), are not understandable
(s+u+d)(3) transmission
of polarization to L.
hadronisation
expected errors
polarization transfer
for STAR
D. de Florian, M.Stratmann, W.Vogelsang
PRL 81 (1998) 530; PR D57 (1998) 5811
STAR
Hyperon Polarization at STAR
STAR will be able after some upgrades to study
a full set of the hyperon polarization parameters:
I-diff. cross-section, P-polarization, ANasymmetry, R, R’ -spin rotation parameters, A,
A’ -longitudinal spin parameters, DNN -normal
spin transfer parameters and Aij (i,j=n,s,l)-double
spin parameters.
Hyperon polarization as a probe of the QGP.
STAR
STAR Spin Goals
Measure of parity-violating spin asymmetry
for one jet production
пЃІ пЃІ
p пЂ« p п‚® jet пЂ« X
Standard Model test
A LL пЂЅ
PV
(Пѓ пЂ« пЂ« пЂ« Пѓ пЂ­ пЂ­ ) пЂ­ (Пѓ пЂ« пЂ­ пЂ« Пѓ пЂ­ пЂ« )
(Пѓ пЂ« пЂ« пЂ« Пѓ пЂ­ пЂ­ ) пЂ« (Пѓ пЂ« пЂ­ пЂ« Пѓ пЂ­ пЂ« )
Asymmetry is nonzero due to electroweak QCD interference (g & Z0)
New parity-violating interactions could lead
to large modifications of the SM predictions
Search for
quark compositeness
new short-range interaction
STAR
пЃІ пЃІ
p пЂ« p п‚® Оі пЂ« jet пЂ« X
Double spin asymmetry:
DG (x) determination via ALL
п‚® п‚®
in p + p п‚® пЃ§ + jet + X
Compton
A LL пЂЅ
ОґA LL пЂЅ
BEMC
N пЂ« пЂ­ RN
пЂ­
P1 P2 N пЂ« пЂ« RN
пЂ­
1
1
1 пЂ­ (P1 P2 A LL )
P1 P2
N пЂ« пЂ« RN
2
пЂ­
N+(-) : Spin dependent event yield
R: Relative luminosity
P: Beam polarization
annihilation
BEMC+EEMC
О”G пЂѕ 0
О”G пЂј 0
ALL is sensitive to DG
G.Skoro, M.T., hep-ph/0009028; E2-2001-40,JINR
STAR
Sensitivity to Gluon Polarization at RHIC
DG reconstruction
пЃ¬
пЃ¬
пЃ¬
пЃ¬
пЃ¬
пЃ¬
Simulation based on Pythia
including trigger and and jet
reconstruction efficiencies
Coverage of EMC (barrel) +
EEMC (endcap)
пѓ° 0 < О¦ < 2ПЂ and -1 < О· < 2
Jet reconstruction: Cone
algorithm
(seed = 1.5 GeV, R = 0.7)
Luminosity: 320 pb-1
Polarization: 0.7
пѓ–s = 200GeV
xg , xq reconstruction
Comparison with other
experiments
STAR scans a wide range of xg=0.01-0.3
STAR
Double spin asymmetry ALL: Inclusive jet production
DG (x) determination via ALL in
пЂў
p+пЂў
p п‚® jet+ jet + X
Sign of О”G ?
1
2
пЃ¬
пЃ¬
пЃ¬
пЃ¬
пЃ¬
пЂЅ
1
2
О”G пЂѕ 0
О”ОЈ пЂ« О”G пЂ« L z пЂ« L z
q
пЃІ пЃІ
p пЂ« p п‚® jet пЂ« X
g
Simulation based on Pythia including jet
reconstruction efficiencies
Coverage of EMC(barrel)+EMC(endcap)
пѓ° 0 < О¦ < 2ПЂ and -1 < О· < 2
Jet reconstruction: Cone algorithm
(seed = 1.5 GeV, R = 0.7)
Luminosity: 8.1031 cm-2 s-1 пѓ–s = 200 GeV
Polarization: 0.7
ALL is sensitive to sign of DG
G.Skoro, M.T., M.Zupan
Nuovo Cim. A111(1998)353
Nuovo Cim. A112(1999)809
О”G пЂј 0
пЃІ пЃІ
p пЂ« p п‚® dijet пЂ« X
О”G пЂѕ 0
О”G пЂј 0
STAR
Flavor Decomposition of the proton’s spin
Spin parity-violated asymmetry
–
–
Du , Dd determination via ALPV in
п‚®
p+п‚®
p п‚® W В± + X @ пѓ– s = 500 GeV
p ( p)
п‚ п‚ p ( p)
Forward (backward) lepton measurement
eпЂ«
A L ( p p) п‚® D d / d
eпЂ«
A L ( pp ) п‚® D u / u
eпЂ­
A L ( p p) п‚® D u / u
eпЂ­
A L ( pp ) п‚® D d / d
Blue beam
toward endcap
Yellow beam
away from endcap
Detect W В± in STAR via isolated high-pT
daughter lepton, without away-side jet
STAR
Summary
Single spin asymmetry AN is measured by BBC. Precision is <10-3 allowing to
control the transversal components of the beam polarization.
Significant single spin asymmetry in the inclusive p0 production is revealed
by FPD in the polarized proton beam large xF region at s1/2 =200 GeV.
First single and double spin measurements in inclusive LCP production are
made at STAR with transversally polarized protons. Measurements were done
in the level of precision <10-2. Asymmetries are compatible with zero.
New measurements were done in this year with longitudinally polarized
protons.
STAR at RHIC started a new generation of proton spin structure studies
gluon contribution to the proton’s spin
spin/flavor decomposition of the sea
double-spin asymmetries
polarization transfer
transversity
STAR
STAR Spin Results:
Forward Pion Asymmetry and Cross Section
p + p  “p0”+ X , s = 200 GeV
• Measured cross sections consistent with pQCD calculations.
• Large spin effects observed for s = 200 GeV pp collisions, qualitatively
consistent with models extrapolating from FNAL E704 data at пѓ–s = 20 GeV.
• Large normalization uncertainty on measured AN is reduced when Pbeam
calibration exp’t is done.
Документ
Категория
Презентации
Просмотров
6
Размер файла
2 996 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа