progress in pdfslss.fnal.gov/conf/c0605043/olness_f.pdfj. morfin, c. keppel, v. radescu, d. mason...
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Progress in PDFs
Conspirators: P. Nadolsky, S. Berge, I Schienbein,
J.-Y. Yu, W. Tung, S. Kretzer, J. Owens, S. Kuhlmann, J. Pumplin, H. LaiJ. Morfin, C. Keppel, V. Radescu, D. Mason
Fred Olness
SMU
Workshop on Intersections of
Nuclear Physics with
Neutrinos and Electrons
4 May 2006
Special thanks to Jeff Owens for his APS 2005 material
PDF StatusEvolutionNuclear CorrectionsTarget Mass Corrections
Strange Quark PDFDrell-YanHeavy Quark Effects
PDF STATUS
Many different experiments are required for Global Fit to proton structure
Data points used for global PDF fit
QCUT
1 / (Momentum Fraction)
Ener
gy S
cale
(GeV
)
Q > 2 GeVW > 3.5 GeV
Kinematics&
Evolution
Low Q & Hi-x: Feeds down to Hi Q & intermediate x
Tevatronx range for LHCborrowed from R. Thorne, et al., hep-ph/0507015
Nuclear Corrections
| eη|0 0.5 1 1.5 2 2.5
Cor
rect
ed A
sym
met
ry
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5 < 35 GeV T25 < E
Run II data from CDF (170pb-1)
Run II improved statistics
Nuclear Corrections at Large-x
�Tevatron W-Asymmetry data constrains d/u out to x ≈0.3�DIS data extends to higher x, but Nuclear Corrections important�Time to revisit
Large x parton distributions.S. Kuhlmann, et al.,Phys.Lett.B476:291-296,2000
0.1
1
1 10 100 1000
F 2(x
,Q2 )
Q2 (GeV/c)2
x=0.015 (X3)
x=0.045 (X1.8)
x=0.080 (X1.3)
x=0.125x=0.175x=0.225
x=0.275
x=0.35
x=0.45
x=0.55
x=0.65
x=0.75NuTeVCCFR
CDHSWNuTeV fit
0.1
1
10
1 10 100
xF3(
x,Q
2 )
Q2 (GeV/c)2
x=0.08
(x40)x=0.015
x=0.045
(x1.2)
(x2)
(x3.5)
(x1.5)
(x12)
(x6)
x=0.125
x=0.175
x=0.225
x=0.275
x=0.35
x=0.45
x=0.55
x=0.65
x=0.75NuTeV
CCFR 97CDHSW
NuTeV fit
NuTeV Structure Functions
NuTeV higher at large-xImplications for valence PDF
Nuclear Corrections important at large-x
Parton X0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
Mea
n D
ata/
Th
eory
0.6
0.7
0.8
0.9
1
1.1
1.2
1.3
1.4No Nuclear Correction
NMC Nuclear Correction
Kulagin/Petti Nuclear Correction
No Nuclear Correction
NMC Nuclear Correction
Kulagin/Petti Nuclear Correction
NuTeV Neutrino Data, NLO QCD, CTEQ6.1M
Nuclear Corrections for Neutrino Data
NMC too large at both small & large-x
K/P does better
Shape not ideal
Large-x not too bad
Small-x: what to do??
K/P depends on F123
Should correction depend on NC/CC???In progress: NuTeV Cross section data analysis
TargetMass
Corrections
1) Nachtmann variable ξ
2)p- ≠ ξP- results in mixing partonic & hadronic F's
(diagonal in helicity basis)
3) Transverse momentum (kT) effects
4) Threshold effects as x → 1
�=2x
1��1�4M2 x2
Q2
Sources of Target Mass Corrections
F.M. Steffens, W. Melnitchouk, nucl-th/0603014
Target Mass Corrections:
Size of TMC vs. Q and X
Strange
Quark PDF
What is relative uncertainty on PDFs' ???
u-quark
x
Gluon
x
Previously, s(x) was tied to u-bar and d-bar via kappa:
s�x�= �s�x�= ��u �x ���d �x �
2
Question: Do we really know the s-quark PDF to 5%???
0.01 0.03 0.1 0.3 0.70.6
0.8
0.9
1.
1.1
1.2
1.4
s-quark
x
40 CTEQ6M PDF sets
5% uncertainty???
Ratio
to C
TEQ
6
40 PDF Sets explore parameter space
Gluon important for Higgs production
Hi-x behavior constrained by DIS data
CTEQ6: Pumplin, Stump, Huston, Lai, Nadolsky, Tung, JHEP 0207, 012 (2002)
PDF Uncertainty band compared to
CTEQ6M
What is true uncertainty on s-quark PDF???
0.01 0.03 0.1 0.3 0.70.6
0.8
0.9
1.
1.1
1.2
1.4
s-quark
x
5% uncertainty???
Warning: The Director General has determined the band of PDF's can greatly
underestimate the true uncertainty
0.01 0.03 0.1 0.3 0.70.6
0.8
0.9
1.
1.1
1.2
1.4
Additional sets with more general parameterization
s-quark
x
Ratio
to C
TEQ
6
Ratio
to C
TEQ
6
Curves shown are examples; this is not an exhaustive set
40 CTEQ6M PDF sets Closer to the true error
Dimuons are ideal signal of s(x)
di-muon NuTeV CCFR CombinedNeutrino 5012 5030 10042Anti-Nu 1458 1060 2518
∗ High stats & high precision data* Best constraints on strange quark
M. Goncharov et al., NuTeV Collaboration PRD 64:110226 (2001)
NuTeV Collaboration (D. Mason for the collaboration). Moriond 2004, hep-ex/0405037
FragmentationFunction
DecayDistribution
Charm Production
cross-section
Di-muon cross-section
d±�
�
dx dy= � d d�
d� c
dx dy d � Dc� � � �c ����E
±�5 GeV
Global Fit: vary s(x) distribution
CTEQ6M Constrained Mixed FreeCCFR Nu 1.02 0.85 0.79 0.72
CCFR Nu-bar 0.58 0.54 0.59 0.59NuTeV Nu 1.81 1.70 1.55 1.44
NuTeV Nu-bar 1.48 1.30 1.15 1.13BCDMS F2p 1.11 1.11 1.11 1.11BCDMS F2d 1.10 1.10 1.10 1.11
H1 96/97 0.94 0.95 0.94 0.94H1 98/99 1.02 1.03 1.03 1.03
ZEUS 96/97 1.14 1.14 1.14 1.15NMC F2p 1.52 1.50 1.51 1.49
NMC F2d/F2p 0.91 0.91 0.91 0.91
1.05 1.07 1.06 1.03CCFR F2 1.70 1.71 1.81 1.88CCFR F3 0.42 0.42 0.44 0.42
E605 0.82 0.82 0.82 0.83NA51 0.62 0.61 0.52 0.52
0.82 0.83 0.82 0.82E866 0.39 0.40 0.39 0.38
D0 Jets 0.71 0.65 0.70 0.67CDF Jets 1.48 1.48 1.48 1.47TOTAL 2173 2144 2142 2133
χ2 / DOF
NMC F2d/F2p <Q2>
CDF � Asym
CTEQ6: J. Pumplin, et al., JHEP 0207:012,2002
Reasonable χ2 values(CTEQ6 did not fit di-muon data)
More parameters, lower value of χ2
Only di-muon data is sensitive to s(x) !!!
∴Idea: ν and ν-bar data separately determine
s and s-bar distributionsTotal of 1991 data points
Only di-muon data is sensitive
to s(x) !!!
What does the ∆s(x) strange PDF look like?
10-5 .001 0.01 0.05 0.1 .2 .3 .4 .5 .6 .7
x
-2×10-3
0
2×10-3
4×10-3
6×10-3
8×10-3
S- (
= x
s- (x,Q
)) d
x/dz
Momentum Asymmetry
(scale: linear in z = x1/3
)
x [s(x) - s(x)]ν
NX
sc
µ
W
[S�]��0
1
x {s �x���s �x �}
�0.0040�[S�]��0.0010
General range of the asymmetry
Olness, Pumplin, Stump, Huston, Nadolsky, Lai, Kretzer, Owens, Tung, Eur.Phys.J.C40:145-156,2005Kretzer, Olness, Pumplin, Stump, Tung, Reno, PRL 93,041802 (2004)
∆s(x): large uncertainty affected by: � charm fragmentation� charm mass� PDF set
�0
1{s� x ���s � x �}=0
• Tremendous new information on BOTH s+s and s-s
• Work is ongoing: extend to higher orders
• Include this information in next generation PDF sets
Does this solve the SinθW problem???
D. Mason for the NuTeV Collaboration; AIP Conf.Proc.792:851-854,2005 S. Catani, D. de Florian, G. Rodrigo, W. Vogelsang; Phys.Rev.Lett. 93 (2004) 152003
� x �s��s ����5×10�4
Three-loop kernel generates asymmetry@ Q2 20GeV2
Kretzer, Mason, Olness PRD 65:074010 (2002)
Fixed Target Drell-Yan
FNAL-E866/NuSea Collaboration (J.C. Webb et al.) AIP Conf.Proc.549:532-535,2002 Al
The radiative corrections change both the normalization of the data w/respect to the theory, and the slope vs x1. The pp data are consistent with MRST w/in errors. The pd aren't.
Fixed Target Drell-Yan
Theory is uncomfortably high at large-x
Implications for valence...
Radiative Corrections in progress
Heavy Quark Effects
NuTeV F2, evaluated with S-ACOT heavy quark scheme, CTEQ6.1M PDFs, and EMC nuclear correction
NuTeV F2, evaluated with zero mass NLO QCD, CTEQ6.1M PDFs, and EMC nuclear correction
Preliminary:generated by Steve Kuhlmann
Preliminary:generated by Steve Kuhlmann
Effect of Fully Massive Calculation
Parton X0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
Mea
n D
ata/
Th
eory
0.6
0.7
0.8
0.9
1
1.1
1.2
1.3
1.4Quark Masses Neglected
Quark Masses Included
NuTeV Neutrino Data, NLO QCD with no Nuclear Correction, CTEQ6.1M
Effect of Fully Massive Calculation
Minimal effect for this kinematic range with inclusive quantityDoes make a difference for specific observables
Progress in PDFs
Conspirators: P. Nadolsky, S. Berge, I Schienbein,
J.-Y. Yu, W. Tung, S. Kretzer, J. Owens, S. Kuhlmann, J. Pumplin, H. LaiJ. Morfin, C. Keppel, V. Radescu, D. Mason
Fred Olness
SMU
Workshop on Intersections of
Nuclear Physics with
Neutrinos and Electrons
4 May 2006
Special thanks to Jeff Owens for his APS 2005 material
PDF StatusEvolutionNuclear CorrectionsTarget Mass Corrections
Strange Quark PDFDrell-YanHeavy Quark Effects