spin physics at rhic - kek · 2004. 3. 5. · • origin of the proton spin 1/2 ? – ∆Σ=...
TRANSCRIPT
Spin Physics at RHIC
“Particle Physics Phenomenology” at KEKMarch 2, 2004
Yuji Goto (RIKEN/RBRC)
March 2, 2004 Yuji Goto (RIKEN/RBRC) 2
Spin physics at RHIC• Longitudinal polarized proton collision
– helicity structure of the proton• gluon polarization
– parity violating asymmetries• Transverse polarized proton collision
– transverse structure/motion = orbital angular momentum– transversity distribution
• last unmeasured leading-twist distribution
– single transverse-spin asymmetries• transversity, higher twist, T-odd structure and fragmentation
functions, …
• Small-angle pp elastic scattering– unpolarized & polarized measurements
March 2, 2004 Yuji Goto (RIKEN/RBRC) 3
Longitudinal polarized proton collision
• Origin of the proton spin 1/2 ?
– ∆Σ = 0.1-0.3: quark contribution by polarized DIS experiments
– gluon contribution• known poorly from scaling violations in pol. DIS experiments,
spanning a small range of Q2
Lg +∆+∆Σ=21
21
)1GeV(
(th)(sys)(stat)0.1 :SMC22
4.15.0
4.02.0
0.13.0
=
=∆ +−
+−
+−
Q
g
nucleon target
γ*
or
or
quark
lepton beampolarized DIS
March 2, 2004 Yuji Goto (RIKEN/RBRC) 4
Gluon polarization
• Polarized semi-inclusive DIS– COMPASS/SMC/HERMES
• Polarized hadron collision– Fermilab E704 π0/multi-photon– RHIC polarized proton collision
lepton beamor
or nucleon target
γ*
gluonheavy flavor
proton beam
proton beam
or
or
gluon
photon
proton beam
proton beam
or
or gluon
gluonheavy flavor
March 2, 2004 Yuji Goto (RIKEN/RBRC) 5
RHIC (Relativistic Heavy-Ion Collider)
March 2, 2004 Yuji Goto (RIKEN/RBRC) 6
RHIC polarized proton collision
BRAHMS & PP2PP
STARPHENIX
AGS
LINACBOOSTER
Pol. Proton Source500 µA, 300 µs
Spin Rotators Siberian Snakes
200 MeV Polarimeter AGS Quasi-Elastic PolarimeterRf Dipoles
RHIC pC CNI PolarimetersAbsolute Polarimeter (H jet)
PHOBOS
AGS pC CNI Polarimeter
Partial Helical Snake
RHIC√s = 50 - 500 GeV
Partial Solenoid Snake
2001 - 2002
2003
2004 −
√s = 200 GeV transverse polarized proton collisions
√s = 200 GeV transverse+longitudinal polarized proton collisions
√s = 200 GeV longitudinal polarized proton collisions
March 2, 2004 Yuji Goto (RIKEN/RBRC) 7
RHIC polarized proton collision• High √s and high Q2
– √s = 200 GeV and 500 GeV in the future– perturbative QCD applicable
• scale dependence of the NLO pQCD calculation in the cross section measurement
• scale dependence is expected to largely cancel in the asymmetry measurement
M. Stratmann and W. Vogelsang
March 2, 2004 Yuji Goto (RIKEN/RBRC) 8
RHIC polarized proton collision
• Cancellation of systematic uncertainty– flexible combination of spin
direction every crossing
STAR and IP12
PHENIX and PP2PP
IP4 and IP10
March 2, 2004 Yuji Goto (RIKEN/RBRC) 9
RHIC polarized proton runs• Run2: 2001-2002
– transverse polarized collision 150 nb-1
– polarization ~15%• Run3: 2003
– transverse+longitudinal polarized collision 600 nb-1
– polarization ~27%• Run4: 2004 March-April (5 weeks)
– polarized proton commissioning run to develop more luminosity and more polarization
– longitudinal polarized collision data expected• Run5: 2005
– physics run again
March 2, 2004 Yuji Goto (RIKEN/RBRC) 10
Longitudinal polarized proton collision
• Double longitudinal-spin asymmetry
– P: polarization• AGS/RHIC proton-carbon CNI polarimeter• polarized hydrogen gas-jet (absolute polarimeter)• local polarimeters at experiments
– N: yield– R: relative luminosity
++
−+
−+++
−+++
−+++
−+++
=
⋅+⋅−
⋅⋅
=
+−
=
LLR
NRNNRN
PP
ddddALL
21
1σσσσ parallel
anti-parallel
March 2, 2004 Yuji Goto (RIKEN/RBRC) 11
STAR
March 2, 2004 Yuji Goto (RIKEN/RBRC) 12
PHENIX
March 2, 2004 Yuji Goto (RIKEN/RBRC) 13
PHENIX
March 2, 2004 Yuji Goto (RIKEN/RBRC) 14
PHENIX π0 cross section– data covers over 8 orders of
magnitude• pT = 1 – 13 GeV/c
– NLO pQCD calculation is consistent with our data
• within the scale µ = pT/2 - 2pT
– confidence in understanding subprocesses
– input to the fragmentation-function uncertainty
9.6% normalization error not shown
Run2 resulthep-ex/0304038PRL 91, 241803 (2003)
March 2, 2004 Yuji Goto (RIKEN/RBRC) 15
(GeV/c)Tp0 1 2 3 4 5 6
LL
A
-0.15
-0.1
-0.05
0
0.05
0.1=200 GeVs from pp at LL A0π
PHENIX Preliminary
Polarization scaling error~30% is not included
GRSV-max
GRSV-std
GRSV-max:∆G = 1.84
GRSV-std:∆G = 0.42
(at Q2 = 1 GeV2)
PHENIX ALL(π0)
Polarization scaling error δP/P ~30% is not included:
- Analyzing power AN (100 GeV) = AN (22 GeV) is assumed
- δP/P ~ 30%: combined stat. and syst. error for AN (22 GeV) [AGS-E950]
B. Jäger et al.,PRD 67 (2003) 054005NLO pQCD calculations
March 2, 2004 Yuji Goto (RIKEN/RBRC) 16
Gluon polarization
• SMC– semi-inclusive hadron-pair measurement– photon-gluon fusion
• COMPASS– 2004: δ(∆G/G)stat ~ 0.15 ??
lepton beamor
or nucleon target
γ*
gluonheavy flavor
March 2, 2004 Yuji Goto (RIKEN/RBRC) 17
Gluon polarization
• B. Jäger et al., hep-ph/0310197– NLO pQCD calculation– cannot make sizable negative ALL(π0) in this kinematic
range
gg
gq
Fraction of π0s produced
March 2, 2004 Yuji Goto (RIKEN/RBRC) 18
Transversity– last unmeasured leading-twist distribution
• Near future– π+π- interference fragmentation function
• J. Collins, S. Heppelmann, and G. Ladinsky, Nucl.Phys. B420 (1994)565
• R. Jaffe, X.Jin, J. Tang Phys. Rev. D57 (1999)5920
– Collins effect in jets• J.C. Collins, Nucl. Phys. B396, 161(1993)
– inclusive jet production• W. Vogelsang and M. Stratmann, RBRC Workshop on
Transversity (2000)
)( XJetppAT ++→⊥ π
( )XppAT +→ −+⊥ ),( ππ
March 2, 2004 Yuji Goto (RIKEN/RBRC) 19
Transversity at PHENIX
• Transversity throught π+π-
interference FF– non-vanishing “support”
only in the ρ mass region
2P
)( 1xqiδ
)( 2xqi
11Px
22Pxijσ∆
1psv
+π−π
Jet
Jet
ProtonStructure
Hard ScatteringProcess
InterferenceFragmentation
[ ][ ]{ } [ ])(ˆsin)(ˆsin...ˆ)()(
...ˆ)(ˆ)()()cos()sin(sinsin
461
112
002
21
211010 zqzqxGxG
zqxGxqNNNN
PA qq
gg
qgqgI
beam δδσδσδδδ
φδδδδπ+⋅+⋅
+⋅⋅⋅⋅−−=
+−
= ←→
←→
⊥
200 GeV
500 GeV
][GeVp jetT
qqqqqq
m
I ∆+≤=
===
δδ
φη σρ
2,3/ˆˆ4ˆ
1cos83.0,0
102
,
GeV,
Maximum Asymmetry
ρ,σ
March 2, 2004 Yuji Goto (RIKEN/RBRC) 20
Transversity throught π+π- interference FF• Projected asymmetry
pair vs TT pXpA )( +→ −+⊥ ππ
Small aymmetry below5% but good rate!
MeV MeV GeV
GeV
9508004
4
32
22
21
,
1
21
<<
>+
>
=∫ −
mpp
E
pbLdt
TT
ππGeV) Tang 85.0,1(cos == mA φ
)1010Tang sin(sinsincos δδδδφ −⋅⋅⋅⋅A
For 32pb-1 (1 week of running)
5.2 Million events in 32 pb-1
15% with pair after cuts
March 2, 2004 Yuji Goto (RIKEN/RBRC) 21
Fragmentation function at BELLE
• Collins fragmentation function– e+e- → π+
jet1π-jet2X
– reaction plane defined with beam (z-axis) and jet axis
– product (π) plane defined with π and jet axis
– φ: angle between the planes
A ∝ Η1⊥(z1)Η1
⊥(z2)cos(φ1+φ2)– can analyze with/without
using jet axisA ∝ Η1
⊥(z1)Η1⊥(z2)cos(2φ)
S. Lange, A.Ogawa (STAR)K. Hatsuko, M.G-Perdekamp (PHENIX)
March 2, 2004 Yuji Goto (RIKEN/RBRC) 22
Fragmentation function at BELLE
• π+π- interference fragmentation function– e+e- → (π+π-)jet1(π-π+)jet2X– stay in the mass region around ρ−mass– find pion pairs in opposite hemispheres– observe angles φ1+φ2 between the event-plane (beam,
jet-axis) and the two pion planes.A ∝ δqΙ(z1, m1) δqΙ(z2, m2)cos(φ1+φ2)
March 2, 2004 Yuji Goto (RIKEN/RBRC) 23
HERMES
• Polarized semi-inclusive DIS
longitudinalpolarized target
transversepolarized target
ULA CollinsUTA
Aπ+~Aπ0>0Aπ-<0 and smaller
Aπ+>0Aπ0~Aπ-<0 and larger
March 2, 2004 Yuji Goto (RIKEN/RBRC) 24
Single transverse-spin asymmetries
• Left-right asymmetry
• Fermilab E704– √s = 20 GeV– unexpected large
asymmetry at large-xF
– 0.2 < pT < 2.0 GeV/c
left
right
Fermilab-E704LRRL
LRRLN NNNN
NNNNP
A↓↑↓↑
↓↑↓↑
⋅+⋅
⋅−⋅⋅=
1
↓
↑
↓↑
↓↑ =⋅+⋅−
⋅=LL
RNRNNRN
PA
LL
LLN 1
square-root formula
luminosity formula
March 2, 2004 Yuji Goto (RIKEN/RBRC) 25
STAR forward π0
• FPD (Forward Pion Detector)– EM calorimeters to cover large-
xF region
FPDEastBBC West BBC East
March 2, 2004 Yuji Goto (RIKEN/RBRC) 26
STAR forward π0
• Cross section– consistent with NLO pQCD calculations
• AN– large spin effects observed for √s = 200 GeV pp
collisionshep-ex/0310058
March 2, 2004 Yuji Goto (RIKEN/RBRC) 27
Neutron asymmetry at IP12• PHENIX local polarimeter R&D
EM Cal Base
PbWO4
Charge Veto
Neutron VetoHadron Cal Base
Pb
Scintillator
W+Fiber Cal
Post-shower
March 2, 2004 Yuji Goto (RIKEN/RBRC) 28
Neutron asymmetry at IP12Hadron Cal EM Cal
AN = −0.126±0.008±0.041AN = −0.116±0.018±0.020
preliminary preliminary
preliminaryvery forward neutronAN ~ -12%xF > 0.2pT < 0.3 GeV/c
March 2, 2004 Yuji Goto (RIKEN/RBRC) 29
PHENIX local polarimeter
• ZDC + SMD– ZDC: Zero-Degree Calorimeter
• hadron calorimeters at the most forward location (~18m from IP)
– SMD: Shower-Maximum Detector• plastic scintillator array• X: 7 array, Y: 8 array
1 ZDC
SMD
March 2, 2004 Yuji Goto (RIKEN/RBRC) 30
Blue Yellow
Blue Yellow
Blue Yellow
PB=35.5% PB=37%
PHENIX local polarimeterSpin Rotators OFF
Spin Rotators ONCorrect Current !
Spin Rotators ONCurrent Reversed
transversely-polarizedproton collisions
radially-polarizedproton collisions
longitudinally-polarizedproton collisions
March 2, 2004 Yuji Goto (RIKEN/RBRC) 31
PHENIX local polarimeter
ST is measured with PHENIX local polarimeter
001.013.009.032.974.)( ++
−−=yellowSL
up-down asymmetryleft-right asymmetry
222 ,1 radialTverticalTTTL SSSSS −− +=−=
000.005.009.014.993.)( ++
−−=blueSL
March 2, 2004 Yuji Goto (RIKEN/RBRC) 32
STAR local polarimeter
• BBC (Beam-Beam Counter)– η = 2 ~ 5– AN ~ +0.5%
Blue beam, BBC West310−×
310−×
Run# Run#Rotators ONOFF
ε CNI (ON-LINE)
εLR BBC = 0.13(2)
εTB BBC = -0.24(2)
Mea
sure
d as
ymm
etry
Yellow beam, BBC Eastε CNI (ON-LINE)
εLR BBC = - 0.07(2)
εTB BBC = - 0.04(2)
drop drop
CNI CNI
BBCBBC
Rotators ONOFF
March 2, 2004 Yuji Goto (RIKEN/RBRC) 33
Summary• We are giving first results of spin physics at RHIC
– gluon polarization in longitudinal polarized proton collisions (ALL)– single transverse-spin asymmetries (AN)
• Many developments have been done and are ongoing– polarimetry
• AGS/RHIC, polarized hydrogen gas-jet• local polarimeter: application of the AN results
– more luminosity and polarization• AGS snakes
– detector upgrades• Many future topics
– more gluon polarization data– transversity (with fragmentation functions)– parity-violating asymmetries– small-angle pp elastic scattering
March 2, 2004 Yuji Goto (RIKEN/RBRC) 34
Backup slides
March 2, 2004 Yuji Goto (RIKEN/RBRC) 35
STAR
RICH: |η|<0.3, ∆φ = π/6
Central Trigger Barrel |η| < 1
Time Projection Chamber |η|< 1.5
Silicon VertexTracker
Forward TPCs2.4 < |η| < 4.0
Barrel EMC0< η< 1 ∆φ =2π/5
Endcap EMC1< η <2 ∆φ = 2π
Forward Pion Detector (FPD) 3.1 < η < 4.4
+ upgradeBeam-Beam Counters
2 .4< |η| < 5.0
+ patch
Magnet Coils
0.5T
4.2 m
2 m
|η| < 1 ∆φ = 2π
Run0Run1Run2 and beyond
B=0.25T
~
Spin2001-2002
2003-
March 2, 2004 Yuji Goto (RIKEN/RBRC) 36
Relative luminosity– achieved relative luminosity precision δR = 2.5×10-4 → δALL =
0.2%• pessimistic estimation limited by ZDC statistics (30 times less than
BBC statistics used in relative luminocity measurements)– ALL of BBC relative to ZDC consistent with zero (<0.2%)
• strong indication that both ALLs are zero (very different kinematical regions, different physics signals)
BBC
ZDC
March 2, 2004 Yuji Goto (RIKEN/RBRC) 37
Zero-Degree Calorimeter (ZDC)– tungsten + scintillating fiber hadron calorimeter– 5.1 λI, 149 X0 (3 modules)
beam
beam
March 2, 2004 Yuji Goto (RIKEN/RBRC) 38
High-pT trigger
• √s=200 GeV data collected with high-pT photon trigger– Based on EMCal; Threshold
~1.4 GeV/c– Rejection factor ~110– Analyzed data sample: – 42.7M events (~0.215 pb-1)– √⟨PbPy⟩ ~ 26%
• Minimum Bias data – To obtain “unbiased” π0 cross
section at low pT
– For high-pT photon trigger efficiency study
Pi0 efficiency plateaus for pT>4 GeV/cLimited efficiency at pT<4 GeV/c:
1-2 GeV/c: 6%2-3 GeV/c: 60%3-4 GeV/c: 90%4-5 GeV/c: 95%
Monte Carlo reproduces Data well
Trigger efficiency for π0
March 2, 2004 Yuji Goto (RIKEN/RBRC) 39
π0 reconstruction
– results obtained for four pT bins from 1 to 5 GeV/c
– π0 peak width varies from 12 to 9.5 MeV/c2
from lowest to highest pT bins
– background contribution under π0
peak for ±25 MeV/c2
mass cut varies from 45% to 5% from lowest to highest pTbins
2-3 GeV/cBckgr=17%
3-4 GeV/cBckgr=7%
4-5 GeV/cBckgr=5%
1-2 GeV/cBckgr=45%
March 2, 2004 Yuji Goto (RIKEN/RBRC) 40
π0 counting for ALL
Nπ0: ±25 MeV/c2 around π0 peak (and also ±15 and ±35 MeV/c2 for cross checks)
Nbck1: Two 50 MeV/c2 wide areas adjacent to π0 peak
Nbck2: 250 MeV/c2 wide area between π0 and η peaks
12k3.9k39k38k34k4-5
83k27k208k201k176k3-4
989k335k1146k1059k874k2-3
3478k1470k2129k1777k1278k1-2
Nbck2Nbck1Nπ035 MeV/c2
Nπ025 MeV/c2
Nπ015 MeV/c2
ptGeV/c
Nπ0 and Nbck accumulated statistics
March 2, 2004 Yuji Goto (RIKEN/RBRC) 41
ALL Calculations
ALL averaged over fills
3-4 GeV/c
1-2 GeV/c
4-5 GeV/c
2-3 GeV/c 1-2 GeV/cALL= -2.8%±1.2%χ2/ndf = 64/48
2-3 GeV/cALL= -2.2%±1.5%χ2/ndf = 34/48
3-4 GeV/cALL= -0.2%±3.3%χ2/ndf = 49/48
4-5 GeV/cALL= -2.3%±7.4%χ2/ndf = 39/48
March 2, 2004 Yuji Goto (RIKEN/RBRC) 42
Bunch shuffling
• Systematic error evaluation– randomly shuffle the bunch
combination to calculate false asymmetries
-0.2 -0.1 0 0.1 0.20
20
40
60
80
100
120
140
hasym_set0_pt0Nent = 1000 Mean = 0.000224RMS = 0.01168
hasym_set0_pt0Nent = 1000 Mean = 0.000224RMS = 0.01168
-0.2 -0.1 0 0.1 0.20
20
40
60
80
100
120
hasym_set0_pt1
Nent = 1000 Mean = 0.000916RMS = 0.01407
hasym_set0_pt1
Nent = 1000 Mean = 0.000916RMS = 0.01407
-0.2 -0.1 0 0.1 0.20
20
40
60
80
100
hasym_set0_pt2
Nent = 1000
Mean = 0.000248
RMS = 0.03221
hasym_set0_pt2
Nent = 1000
Mean = 0.000248
RMS = 0.03221
-0.3 -0.2 -0.1 0 0.1 0.2 0.30
20
40
60
80
100
hasym_set0_pt3
Nent = 1000
Mean = -0.004048
RMS = 0.06958
hasym_set0_pt3
Nent = 1000
Mean = -0.004048
RMS = 0.06958
2-3 GeV/c
3-4 GeV/c 4-5 GeV/c
1-2 GeV/c
0 0.5 1 1.5 2 2.50
10
20
30
40
50
60
70
80
90
hchi2_set0_pt0Nent = 1000 Mean = 1.043RMS = 0.2103
hchi2_set0_pt0Nent = 1000 Mean = 1.043RMS = 0.2103
0.5 1 1.5 2 2.50
10
20
30
40
50
60
70
80
90
hchi2_set0_pt1Nent = 1000 Mean = 1.001RMS = 0.2157
hchi2_set0_pt1Nent = 1000 Mean = 1.001RMS = 0.2157
0 0.5 1 1.5 2 2.50
10
20
30
40
50
60
70
80
hchi2_set0_pt2Nent = 1000 Mean = 1.069RMS = 0.2155
hchi2_set0_pt2Nent = 1000 Mean = 1.069RMS = 0.2155
0.5 1 1.5 2 2.50
10
20
30
40
50
60
70
80
90
hchi2_set0_pt3Nent = 1000 Mean = 0.9279RMS = 0.1961
hchi2_set0_pt3Nent = 1000 Mean = 0.9279RMS = 0.1961
2-3 GeV/c
3-4 GeV/c 4-5 GeV/c
1-2 GeV/c
⟨χ2/ndf⟩ ~ 1 ALL: consistent with statistical error
March 2, 2004 Yuji Goto (RIKEN/RBRC) 43
ALL results
0.10±0.140.38±0.24-0.013±0.073-0.023±0.074-0.014±0.0794-5
0.019±0.0550.094±0.092-0.001±0.032-0.002±0.033-0.017±0.0353-4
-0.022±0.017-0.035±0.027-0.022±0.014-0.022±0.015-0.027±0.0162-3
0.004±0.010-0.006±0.014-0.024±0.011-0.028±0.012-0.023±0.0141-2
35 MeV/c225 MeV/c215 MeV/c2
ptGeV/c
bckLLA +0π bck
LLA +0π 1bckLLA 2bck
LLAbckLLA +0π
March 2, 2004 Yuji Goto (RIKEN/RBRC) 44
ALL results: plots
π0+bck 35 MeV/c2
π0+bck15 MeV/c2
Bck2
π0+bck 25 MeV/c2
Bck1
March 2, 2004 Yuji Goto (RIKEN/RBRC) 45
Gluon polarization
• Fermilab E704– fixed target experiment– √s = 19.4 GeV
ALL(π0) PLB 261 (1991) 197. ALL(multi-γ) PLB 336 (1994) 269.
… also shows negative ALL …
March 2, 2004 Yuji Goto (RIKEN/RBRC) 46
Gluon polarization• Direct photon production
– Gluon Compton process dominant• factorization
LLqp
g
gTLL axA
xgxg
pA ˆ)()()(
)( 1 ⋅⋅∆
=
)(/)( gg xgxg∆)(1 q
p xALLa
GS95 NLO (A)
√s=200GeV320pb-1
√s=500GeV800pb-1
inclusive photon measurementphoton + jet measurement
: gluon polarization: measured in pol. DIS: calculable
March 2, 2004 Yuji Goto (RIKEN/RBRC) 47
PP2PP
to IR2
Roman Pot Station with Detectors ( used in 2002 )
RP Station not used in 2002
Roman Pot above beam
Roman Pot below beam
RHIC Intersection Region with PP2PP Basic CB Setup
0. 100. m -100. m
D0
RP Stations
IRDXD0
RP Stations
-50. m 50. m
Inelastic Detectors
Accelerator magnets ensure that scattered protons have beam momentum
• Spin physics at PP2PP– single transverse-spin
asymmetry measurement in CNI region
• Setup– silicon microstrip detectors
to measure (x,y) coordinates with 100 µm pitch
– Need special tune of accelerator and detectors to approach the proton beams
March 2, 2004 Yuji Goto (RIKEN/RBRC) 48
PP2PP
• 2002 engineering run– collected ~300,000 elastic
scattering events– expected results of 2002 data
analysis• extraction of diffraction cone slope b• calculation of single spin asymmetry
AN
– preliminary |t |-distribution for elastically scattered protons with
• for all azimuthal angles and• for a limited range of azimuth,
resulting in full acceptance in |t |0
500
1000
1500
2000
2500
3000
3500
4000
4500
0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04-t [ GeV2/c2 ]
Arm A
Full φ Acceptance
45° < φ < 135°
Preliminary
March 2, 2004 Yuji Goto (RIKEN/RBRC) 49
Quark polarization flavor decomposition
• W production– parity-violating asymmetry AL
– PHENIX Muon Arms– AL~∆u/u(x)~0.7-0.9 at large-x– no fragmentation ambiguity– x-range limited– complementary to HERMES
semi-inclusive DIS• wide x-range• limited sensitivity to sea flavors
)()()()()()()()(
baba
babaWL xuxdxdxu
xuxdxdxuA+
∆−∆=
+
March 2, 2004 Yuji Goto (RIKEN/RBRC) 50
Transversity throught π+π- interference FF• Invariant mass resolution at PHENIX
accep. into GeV, 0.3
accep. into GeV,
1
2
21 >>
>
,ppz
Eγ
RMS=12 MeVrecpythia mm −
mmm recpythia vs −
GeV GeV
40.21.0
5.0
><<
>
Tpm
z
March 2, 2004 Yuji Goto (RIKEN/RBRC) 51
Parity violating asymmetries
• Jet production• W/Z production
J. -M. Virey, hep-ph/9707470ALL(jet)
J. Murata