AFTER@LHC - LPSC · ZEUS 96–97 e+ p incl. jets 30 / 30 ZEUS 98–00 e± p incl. jets 17 / 30 DØ...

AFTER@LHCECT* Workshop, Feb 4-13, 2013

Summary 1 of WG3:Quarkonia, Heavy-flavour, pA, AA & (n)PDF

I. Schienbein (LPSC Grenoble)E. Ferreiro (USDC, Spain)

Tuesday, February 12, 13

Topics(see Physics Reports 522(2013)239; Stan’s talk)

• Nucleon partonic structure

• Nuclear matter

• nuclear PDFs

• cold nuclear matter effects; A-dependance

• Heavy flavour phyics

• Open and hidden heavy-flavours better go together!

• Vector boson production (W,Z) close to threshold

• Heavy ion physics

• QGP in rest frame of target nucleus

• Spin physics

• Diffractive physics on nucleons and nuclei

• Production of ccq to ccc to bbb states

• Ultra-peripheral collisions

• D and B physics?

• Secondary beams

• high-energy, high-lumi neutrinos?

• pion, kaon beams

• Cosmic ray simulations

��

7 TeV proton beam collisions on a proton or nuclear target --




• Nuclear matter

• nuclear PDFs







• Spin physics





• Secondary beams




��





• Nuclear matter

• nuclear PDFs







• Spin physics





• Secondary beams




��



Iterative procedure(we are in the first round)

• Huge list of possible topics/observables(see Physics Reports 522(2013)239; Stan’s talks)

• Identify possible Key Observables

• Taking into account the competition from other current and future approved experiments

• Ignoring any constraints from budget, available space for detector

• Identify experimental signatures and resulting detector requirements

• Many constraints: Budget, available space for detector, political issues

• Even for a multi-purpose detector: not everything can be measured and one has to make choices

• Need dedicated numerical studies and simulations

• Da Capo al Fine (until EOI as a first milestone!?)


Partonic structure of nucleons


Where can AFTER contribute?• PDFs at large-x poorly known

• gluon

• sea quark distributions

• intrinsic charm/bottom

• Questions

• Which processes at AFTER allow to constrain some of these distributions?

• Large-x PDFs will also be measured at JLAB in DIS. Complementary?Probably yes. Global analyses require different observables for flavour-decomposition!

• Intrinsic charm/bottom will likely also be constrained at the LHC.More refined studies with AFTER possible?

• Where is the tiny large-x gluon relevant? Need parton-parton luminosities; decomposition in subprocesses

• What is the contribution of the gluon at 0.5<x<1to the momentum sum?


16

Data:

● Deep inelastic scattering data● H1 ,ZEUS (ep)● BCDMS,NMC (µp,µd)● CCFR (u-Fe)

● p+pbar -> jet +X : D0, CDF

● DY pp: E605

● DY pd/pp: NA51, E866 (updated)

● W-lepton asymmetry: CDF

● u-DIS dimuon data: Nutev

Backbone: 10^-5 < x < 0.1up > down, evolution of F2 -> gluon

large-x gluon: 0.01 < x <0.5dominated by systematics

d /u

s , s

d/u

info on sea

Asymmetry: info on

at large-x

FL ! gluon

Data used in global analyses of PDFs


Status of MSTW PDF analysis Benchmark W and Z production Higgs, top and jet production !S from DIS Summary

Data sets fitted in MSTW 2008 NLO analysis [arXiv:0901.0002]

Data set !2 / Npts.

H1 MB 99 e+p NC 9 / 8H1 MB 97 e+p NC 42 / 64H1 low Q2 96–97 e+p NC 44 / 80H1 high Q2 98–99 e!p NC 122 / 126H1 high Q2 99–00 e+p NC 131 / 147ZEUS SVX 95 e+p NC 35 / 30ZEUS 96–97 e+p NC 86 / 144ZEUS 98–99 e!p NC 54 / 92ZEUS 99–00 e+p NC 63 / 90H1 99–00 e+p CC 29 / 28ZEUS 99–00 e+p CC 38 / 30H1/ZEUS e±p F charm

2 107 / 83H1 99–00 e+p incl. jets 19 / 24ZEUS 96–97 e+p incl. jets 30 / 30ZEUS 98–00 e±p incl. jets 17 / 30DØ II pp̄ incl. jets 114 / 110CDF II pp̄ incl. jets 56 / 76CDF II W ! l" asym. 29 / 22DØ II W ! l" asym. 25 / 10DØ II Z rap. 19 / 28CDF II Z rap. 49 / 29

Data set !2 / Npts.

BCDMS µp F2 182 / 163BCDMS µd F2 190 / 151NMC µp F2 121 / 123NMC µd F2 102 / 123NMC µn/µp 130 / 148E665 µp F2 57 / 53E665 µd F2 53 / 53SLAC ep F2 30 / 37SLAC ed F2 30 / 38NMC/BCDMS/SLAC FL 38 / 31E866/NuSea pp DY 228 / 184E866/NuSea pd/pp DY 14 / 15NuTeV "N F2 49 / 53CHORUS "N F2 26 / 42NuTeV "N xF3 40 / 45CHORUS "N xF3 31 / 33CCFR "N ! µµX 66 / 86NuTeV "N ! µµX 39 / 40

All data sets 2543 / 2699

• Red = New w.r.t. MRST 2006 fit.

G. Watt 5/60



Data sets fitted in MSTW 2008 NLO analysis [arXiv:0901.0002]

Data set !2 / Npts.

H1 MB 99 e+p NC 9 / 8H1 MB 97 e+p NC 42 / 64H1 low Q2 96–97 e+p NC 44 / 80H1 high Q2 98–99 e!p NC 122 / 126H1 high Q2 99–00 e+p NC 131 / 147ZEUS SVX 95 e+p NC 35 / 30ZEUS 96–97 e+p NC 86 / 144ZEUS 98–99 e!p NC 54 / 92ZEUS 99–00 e+p NC 63 / 90H1 99–00 e+p CC 29 / 28ZEUS 99–00 e+p CC 38 / 30H1/ZEUS e±p F charm

2 107 / 83H1 99–00 e+p incl. jets 19 / 24ZEUS 96–97 e+p incl. jets 30 / 30ZEUS 98–00 e±p incl. jets 17 / 30DØ II pp̄ incl. jets 114 / 110CDF II pp̄ incl. jets 56 / 76CDF II W ! l" asym. 29 / 22DØ II W ! l" asym. 25 / 10DØ II Z rap. 19 / 28CDF II Z rap. 49 / 29

Data set !2 / Npts.

BCDMS µp F2 182 / 163BCDMS µd F2 190 / 151NMC µp F2 121 / 123NMC µd F2 102 / 123NMC µn/µp 130 / 148E665 µp F2 57 / 53E665 µd F2 53 / 53SLAC ep F2 30 / 37SLAC ed F2 30 / 38NMC/BCDMS/SLAC FL 38 / 31E866/NuSea pp DY 228 / 184E866/NuSea pd/pp DY 14 / 15NuTeV "N F2 49 / 53CHORUS "N F2 26 / 42NuTeV "N xF3 40 / 45CHORUS "N xF3 31 / 33CCFR "N ! µµX 66 / 86NuTeV "N ! µµX 39 / 40

All data sets 2543 / 2699

• Red = New w.r.t. MRST 2006 fit.

G. Watt 5/60


Large-x gluon

• Need to constrain gluon at x > 0.4

• Gluon sensitive processes:

• prompt photon production very promising(see David D’Enterria’s talk)

• jet production at AFTER?

• quarkonia production IF theoretical uncertainty due to different “models” < PDF uncertainty(ToDo!)

• open heavy flavour production? (ToDo: need predictions)


Large-x gluon50% at x =0.6

>200% at x=0.7

x=0.6

x=0.6

Naturally, the uncertainties get large where the gluon distribution is very small

Need: gluon sensitive subprocesses split into contributions from gg-channel and qqbar-channel to see where the qqbar-channel takes over; parton-parton-luminosities also useful!


24/31AFTER-LHC, ECT* Trento, Feb'13 David d'Enterria (CERN)

Uncertainties in proton PDFs at high-xUncertainties in proton PDFs at high-x

■ Isolated-g at “low”-√s & high-pT are sentitive to high-x gluons & sea:

Very large uncertainties above x~0.3, also at large Q² !

ubar

ubar

Ratio P

DF

s

MSTW08MSTW08

CT10CT10

NNPDF2.3NNPDF2.3

xG

(x,Q

2=

100G

eV

2)

gluon

gluon

MSTW08MSTW08

CT10CT10

NNPDF2.3NNPDF2.3



(x,Q(x,Q22) map of AFTER isolated-) map of AFTER isolated- gg

■ p-p kinematics at fixed-target LHC:

To access x > 0.3 one needs isolated-g with: pT = x

T√s/2 > 10-20 GeV/c

[D.d'E & J.Rojo, NPB 860 (2012) 311]

AFTER region: pp → g X

x > 0.3 (p,Pb)

x >1 (Pb)



Isolated-Isolated-gg in p(7 TeV)-p(rest): in p(7 TeV)-p(rest): √√s ~ 115 GeVs ~ 115 GeV

■ p-p photon kinematics at fixed-target LHC (backwards rapidities):

To access x > 0.3 one needs isolated-g at: pT = x

T√s/2e-y > 10 GeV/c

■ JETPHOX NLO

pQCD calculations:

p-p at √s=115 GeV

0<y<-3., pT>20 GeV/c

Isolation: R=0.4, ET

had<5 GeV

PDF: CT10 52 eigenval. (90% CL)

Scales: µi = p

T

FF = BFG-II

x-section uncertainties(*) of ±170%

~1 count

(*) (68%CL)/(90% CL) ~ 1.65

L (10 cm H2-target) ~ 2∙103 pb-1/year

(preliminary)


Large-x sea quarks


Large-x sea quarks

• Important for new physics searches at LHC(very heavy states, very large pT)

• Can be constrained by Drell-Yan process

• Benchmark against E906/SeaQuest!

• Question: What can LHC do to constrain large-x PDFs?

• Together with DIS data improves flavour-separation in a global analysis


2

Dilepton production in hadron-hadron collision

p + p(d) → μ+μ- x at 800 GeV/c

(a) Continuum: Drell-Yan process

(b) Vector mesons: J/ψ, Υ FNAL E866

Two components in the dilepton mass spectrum

onannihilatiantiquark -Quark process neticElectromag

on)annihilatiantiquark -(quark fusiongluon -Gluon

ninteractio Strong

Talk by J.-C. Peng


3

Fermilab Dimuon Spectrometer (E605 / 772 / 789 / 866 / 906)

"Nuclear Dependence of Drell-Yan and Quark

1) Fermilab E772

2) Fermilab E789

(proposed in 1986 and completed in 1988)

(proposed in 1989 and completed in 199

onium Production"

"Search for Two-Bo

1)

dy Decays of Heavy Quark Mesons"

"Determination of / Ratio of the Proton via Drell-Ya

(proposed in 1993 and completed in 13) Fermilab E866

4) Fermilab E906

996)

(proposed in 1999, run started in 2012

n

"

)

d u

"Drell-Yan with the FNAL Main Injector"


Experiment Beam energy [GeV] CMS energy [GeV] Luminosity

E866/Nusea

800 38.8 ?

E906/SeaQuest

120 15.5 ?

AFTER 7000 115 ?

... ... ... ...

ToDo: Table of fixed target experiments


5

/ flavor asymmetry from Drell-Yand u

2 21/ 2 ~ (1 ( ) / ( ))2

Drell-Yan: pd pp d x u x

2 2

21 2 1 2

1 2 1 2. .

4 ( ) ( ) ( ) ( )9 a a a a a

aD Y

d e q x q x q x q xdx dx sx x

1 2 :at x x

800 GeV proton beamon hydrogen and deuterium

mass spectrum

Fermilab E866


6

Gluon distributions in proton versus neutron?

E866data: ( ) / 2 ( )p d X p p X

Lingyan Zhu et al., PRL, 100 (2008) 062301 (arXiv: 0710.2344)

If gluon distributions in proton and neutron are different, then charge-symmetry is violated at the partonic level

s


Discussion

• Charge symmetry violation in PDF? (u_p ≠ d_n?)

• Yes, already due to QED radiation since photon couples differently to up and down quarks; but also non-perturbative mechanisms

• See also review of CSV in arXiv:0906.3563

• Origin of ubar ≠dbar?

• SeaQuest is adressing these questions. Where can AFTER contribute? Higher energy, higher lumi!

• Higher invariant masses of lepton pairSuppress higher twist contributions!

• Extended x-range

• Different nuclear targets! (Which ones?)

• ToDo: Make plot of kinematic plane!


Intrinsic charm/bottom

• Has to be there if QCD is right! Question: what is the normalization?

• Need to “measure” heavy quark PDFs:

• Essential for new physics searches, electroweak observables and backgrounds!

• Many important b-quark initiated processes

• Processes at AFTER sensitive to IC/IB

• Gamma+Q production (see talk by T. Stavreva)

• Probably inclusive D meson (B meson) production

• LHC will likely provide constraints on IC/IB

• Question: What can AFTER do better?

• Probe extended x-region? (probe entire BHPS x-shape?)

• Distinguish between intrinsic charm and anti-charm?

• Better precision?

• Disentangle gluon PDF at large-x from intrinsic charm Should be doable using different processes: prompt photons, jets, gamma+c, open/hidden charm


11

Blue band corresponds to CTEQ6 best fit, including uncertainty

Red curves include intrinsic charm of 1% and 3% (χ2 changes only slightly)

A global fit by CTEQ to extract intrinsic-charm

No conclusive evidence for intrinsic-charm 11


Probing IC with γ+Q at AFTERSee talk by T. Stavreva


9

RHIC-PHENIX Direct photon in association with charm / bottom quark jets @ RHIC

- smaller c.m.s energy @ RHIC probes higher x - very sensitive to intrinsic charm

pT min Rapidity Isolation

Photon 7 GeV |yγ|<0.35 R=0.5, pT = 0.7GeV

Heavy Jet 5 GeV |yQ|<0.8 ---

10 15 20 25pTγ(GeV)

0.01

0.1

1

10

100

dσ/d

p Tγ(p

b/Ge

V)

NLOLOBHPSsea-like

pp-> γ +c +X √$ S = 200GeV, CTEQ6.6M

p�T

d�/d

p� T(p

b/G

eV)

p�T

d�B

HP

S

dp� T

/d�

CT

EQ

dp� T

10 15 20 25pTγ

0

1

2

3

4

(dσBHPS;sea-like;LO/dp T

γ)/(dσCTEQ6.6M/dp T

γ)

BHPSsea-likeLO


LHC-CMS

11

50 100 150pTγ(GeV)

0.001

0.01

0.1

1

10

100

dσ/d

p Tγ(p

b/G

eV)

NLOLOBHPSsea-like

pp-> γ +c +X √$ S = 7 TeV, CTEQ6.6M

1.566<|yγ|<2.5

1.5<|yQ|<2

p�T

d�/d

p� T(p

b/G

eV)

50 100 150pTγ

1

1.5

2

2.5

(dσ

BHPS

/dp Tγ

)/(dσ

CTEQ

6.6M

/dp Tγ

)

|yγ|<1.4442, |yQ|<0.5

|yγ|<1.4442, 1.5<|yQ|<2

1.566<|yγ|<2.5, |yQ|<0.5

1.566<|yγ|<2.5, 1.5<|yQ|<2

p�T

d�B

HP

S

dp� T

/d�

CT

EQ

dp� T

Direct photon in association with charm / bottom quark jets @ CMS- CMS cuts on photon & HQ transverse momentum, rapidity & isolation cuts

pT min Rapidity Isolation

Photon 20 GeV |yγ|<1.4442 R=0.4, pT = 4.2GeV

1.56<|yγ|<2.5

Heavy Jet 18 GeV |yQ|<2.0 ---

[CMS notes: CMS PAS EGM-10-005, CMS PAS BPH-10-009]


INTRINSIC CHARM: LHCB

CTEQ6.6c1/CTEQ6.6p p � D0 XGM-VFNS�S = 7 TeV

2.0 � y � 2.52.5 � y � 3.03.0 � y � 3.53.5 � y � 4.04.0 � y � 4.54.5 � y � 5.0

pT (GeV)

1

2

3

4

5

6

7

4 6 8 10 12 14 16 18 20

CTEQ6.6c3/CTEQ6.6p p � D0 X

GM-VFNS

�S = 7 TeV

2.0 � y � 2.5

2.5 � y � 3.0

3.0 � y � 3.5

3.5 � y � 4.0

4.0 � y � 4.5

4.5 � y � 5.0

pT (GeV)

1

1.5

2

2.5

3

3.5

4

4.5

5

4 6 8 10 12 14 16 18 20

CTEQ6.6 updated:BHPS, 3.5 % (c + c̄) at µ = 1.3 GeV high-strength sea-like charm

‹ large effects expected at large rapidities

H. Spiesberger (Mainz) DIS, 27. 3. 2012 30 / 37

arXiv:1202.0439, arXiv:0901.4130


INTRINSIC CHARM: TEVATRON AND RHIC

CTEC6.5cx/CTEC6.5c0p p

– � D0 X

pT (GeV)0.7

0.8

0.9

1

1.1

1.2

1.3

1.4

5 7.5 10 12.5 15 17.5 20 22.5 25

TevatronCTEC6.5cx/CTEC6.5c0

p p � D0 XGM-VFNS

�S = 200 GeV

-1 � y � 1

pT (GeV)0.5

0.75

1

1.25

1.5

1.75

2

2.25

2.5

2.75

3

4 6 8 10 12 14 16 18 20

RHIC

PRD79, 2009

H. Spiesberger (Mainz) DIS, 27. 3. 2012 29 / 37Tuesday, February 12, 13

Partonic structure of nuclei


Where can AFTER contribute?

• nPDFs at large-x very(!) poorly known

• gluon

• sea quark distributions

• intrinsic charm/bottom (will probably not be constrained at LHC!?)

• no need to model A-dependence if sufficient data for a single nucleus (A,Z) available!

• Questions (similar as in proton case)

• Which processes at AFTER allow to constrain some of these distributions?Likely the same as in the proton case.

• Large-x PDFs will also be measured in eA at JLAB in DIS. Complementary?

• Where is the tiny large-x gluon relevant? Same question as for proton case.


EXPERIMENTAL INPUT

Use same data as HKN’07 (up to cuts)

• DIS FA2 /FD

2 data sets: 862 points(before cuts)

• DIS FA2 /FA!

2 data sets: 297 points(before cuts)

• DY data sets !pADY/!pA!

DY : 92 points(before cuts)

Table from Hirai et al.,arXiv:0909.2329

I. Schienbein (LPSC Grenoble) Nuclear PDFs April 2, 2012 18 / 55Tuesday, February 12, 13

23

Modification of Parton Distributions in Nuclei EMC effect observed in DIS

How are the antiquark distributions modified in nuclei?

F2 contains contributions from quarks and antiquarks

(Ann. Rev. Nucl. Part. Phys., Geesaman, Sato and Thomas)


RESULTS: DECUT3 FITDRELL–YAN DATA

0.750.8

0.850.9

0.951

1.051.1

1.15

(#,chi2) = (9,6.68)

C/D

FNAL−E772

DDYσ/A

DYσ

−110 1

0.750.8

0.850.9

0.951

1.051.1

1.15

(#,chi2) = (9,8.31)

Fe/D

FNAL−E772

2x

0.75

0.8

0.85

0.9

0.95

1

1.05

1.1

1.15

(#,chi2) = (9,9.7)

Ca/D

FNAL−E772

−110 1

0.75

0.8

0.85

0.9

0.95

1

1.05

1.1

1.15

(#,chi2) = (9,9.25)

W/D

FNAL−E772

2x


RESULTS: DECUT3 FITDRELL–YAN DATA

0.6

0.8

1

1.2

1.4 Fe/Be

FNAL−E866(99)Q=4.5 GeV

’ADYσ/A

DYσ

(#,chi2) = (28,19.91)

−110 1

0.6

0.8

1

1.2

1.4 W/Be

Q=4.5 GeV

1x

(#,chi2) = (28,36.65)

0.6

0.8

1

1.2

1.4 Fe/Be

Q=5.5 GeV

−110 1

0.6

0.8

1

1.2

1.4 W/Be

Q=5.5 GeV

1x

0.6

0.8

1

1.2

1.4 Fe/Be

Q=6.5 GeV

−110 1

0.6

0.8

1

1.2

1.4 W/Be

Q=6.5 GeV

1x

0.6

0.8

1

1.2

1.4 Fe/Be

Q=7.5 GeV

−110 1

0.6

0.8

1

1.2

1.4 W/Be

Q=7.5 GeV

1x


26 26

Cloet, Bentz, and Thomas, arXiv:0901.355 (see also Kumano et al.)

Isovector mean-field generated in Z≠N nuclei can modify nucleon’s u and d PDFs in nuclei

How can one check this prediction?

Flavor dependence of the EMC effects ?

• SIDIS (Semi-inlusive DIS) and PVDIS (Parity-violating DIS)

• Pion-induced Drell-Yan Tuesday, February 12, 13

Summary: used hadronic processes

• Proton case:

• DY: FNAL E605 (pCu) →info on quark sea

• DY: FNAL E866=NuSea (pd/pp) → info on dbar(x)/ubar(x)

• W-asymmetry (D0 II, CDF II) →info on d(x)/u(x) at large x

• Z-rapidity (CDF II)

• Inclusive jet production (D0 II, CDF II) → info on gluon at large x

• Nuclear case:

• DY: FNAL E772 (C/D, Ca/D, Fe/D, W/D) → info on quark sea

• DY: FNAL E866 (Fe/Be, W/Be) → info on quark sea

• Inclusive pion production: RHIC PHENIX (dAu/pp) → info on gluon

• Note: NO inclusive jet production data available so far;AFTER could measure this with pT = 20 ... 40 GeV →large-x gluon nPDF



Uncertainties in nuclear PDFs at high-xUncertainties in nuclear PDFs at high-x

■ Isolated-g at “low”-√s & high-pT are sentitive to high-x gluons & sea:

Very large uncertainties above x~0.3, also at large Q² !

ubar

Ratio P

DF

s

EPS09 NLOEPS09 NLO

nDSGg NLOnDSGg NLO

nCTEQ NLOnCTEQ NLOgluon

dbar



Isolated-Isolated-gg in Pb(2.76 TeV)-Pb(rest): in Pb(2.76 TeV)-Pb(rest): √√ssNNNN

~72 GeV~72 GeV

■ Pb-Pb photon kinematics at fixed-target LHC:

To access x > 0.3 one needs isolated-g at: pT = x

T√s/2 > 10 GeV/c

■ JETPHOX NLO

pQCD calculations:

Pb-Pb at √sNN

=72 GeV

|y|<0.5, pT>20 GeV/c

Isolation: R=0.4, ET

had<5 GeV

PDF: EPS09

Scales: µi = p

T

FF = BFG-II

(Ongoing determination of uncertainties

with 40 EPS09 eigenvalues ...)

x-section uncertainties of ±270%

~1 count

(very preliminary)

L ~ 7 nb-1/year


W and Z boson production at AFTER


Discussion

• Production of W,Z close to threshold!Test lab. for production of heavy resonances W’,Z’(Maybe too late?)

• Test lab. for QCD calculations of threshold resummation

• ToDo (IS): prediction for W,Z production at NLO at AFTER (VRAP)

• There exist calculations including threshold resummation for W, Z production: invite speakers

• Statistics probably not high enough for PDF studies[measurement of d(x)/u(x)]


Where do the W's and Z's come from ???

u(xa)

W+

d(xb)

For anti-proton:

ddy

W23

GF

2u xa d xb

ddy

W23

GF

2d xa u xb

ddy

W23

GF

2 q q

V q q2 q xa q xb q xb q xa

proton anti-proton

1 100.1

1

10

100

W+

W-

_

_

_

_

__

_

_sc

flavour decomposition of W cross sections

cd

dcsu

us

cs

duud

pp pp

% o

f to

tal

! LO(W

+ ,W- )

"s (TeV)

Therefore

u x u x d x d x

A. D. Martin, R. G. Roberts, W. J. Stirling and R. S. Thorne,Eur. Phys. J. C23, 73 (2002); Eur. Phys. J. C4, 463 (1998)


Au xa d xb d xa u xbu xa d xb d xa u xb

Rdu xb Rdu xaRdu xb Rdu xa

A y

ddy

Wddy

W

ddy

Wddy

W

A bit of calculation

u(xa)

W+

d(xb)

With the previous approximation,

proton anti-proton

Rdu xd xu x

x1,2 x0ey x0 1 y

Rdu x1,2 Rdu x0 y x0R' du

A y y x0R' du x0

Rdu x0

where

Thus, the asymmetry is:

We can make Taylor expansions:

EXERCISE: Verify the above.


A y

ddy l

ddy l

ddy

lddy

l

-0.2-0.15

-0.1-0.05

00.05

0.10.15

0.20.25

0 0.5 1 1.5 2!Lepton Rapidity!

Char

ge A

sym

met

ry CDF 1992-1995 (110 pb-1 e+µ)CTEQ-3MRESBOS

CTEQ-3MDYRAD

MRS-R2 (DYRAD)MRS-R2 (DYRAD)(d/u Modified)

MRST (DYRAD)

F. Abe, et al. [CDF Collaboration], PRL 81, 5754 (1998)Measurement of the lepton charge asymmetry in W boson decays produced in p anti-p collisions,

Charged Lepton Asymmetry

Unfortunately, we don't measure the W directly since W"e#.

Still the lepton contains important information

d u

# e-

W-

1 cos 2


S. Kuhlmann, et al., Large-x parton distributions, PL B476, 291 (2000)

d/u Ratio at High-x

The form of the d/u ratio at large x as a function of

1) Parameterization

2) Nuclear Corrections



W ± ! !±" charge asymmetry at the LHC

AW (yW ) =d!(W+)/dyW " d!(W!)/dyWd!(W+)/dyW + d!(W!)/dyW

#uv (x1)" dv (x1)

u(x1) + d(x1)

A!("!) =d!(#+)/d"! " d!(#!)/d"!d!(#+)/d"! + d!(#!)/d"!

$ AW (yW )% (W± ! #±$)

! η !

0 0.5 1 1.5 2 2.5 3 3.5 4

Lept

on c

harg

e as

ymm

etry

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

-1) 35 pbν l→ATLAS (extrapolated data, W-1) 36 pbνµ →CMS (W-1) 36 pbνµ →LHCb (W

MSTW08 prediction (MC@NLO, 90% C.L.)CTEQ66 prediction (MC@NLO, 90% C.L.)HERA1.0 prediction (MC@NLO, 90% C.L.)

ATLAS+CMS+LHCbPreliminary

=7 TeVs

> 20 GeVlTp

x-410 -310 -210 -110

)2 G

eV4

= 1

02

)(x, Q

v -

dv

x(u

0

0.05

0.1

0.15

0.2

0.25

0.32 GeV4 = 102 distribution at Qv - dvu

MSTW 2008 NLO (90% C.L.)MRST04CTEQ6.6CT10CT10WNNPDF2.1

x-410 -310 -210 -110

)2 G

eV4

= 1

02

)(x, Q

v -

dv

x(u

0

0.05

0.1

0.15

0.2

0.25

0.3

• First PDF constraint from LHC data (! NNPDF2.2).• MSTW08 has input xuv & x0.29±0.02 and xdv & x0.97±0.11.Many other groups assume equal powers ' potential bias.

G. Watt 33/60


Open/hidden heavy-flavour production in pA collisions


Heavy-flavour production in pA collisions: Discussions

• Want J/Psi, Psi(2S), Υ, Χc, Χb(Χc production in AA very difficult; one has to reconstruct forward photons)

• Χc measurement key point (was not possible at NA60 although simultations said it’s possible)needs very accurate MC; very challenging in particular in pA;Bottomonia interesting, relevant and easier than Χc

• Χc relation to CHIC?

• Open and hidden heavy-flavour have to be measured together! (also in AA collisions, see talk by H. Satz)

• Measuring open charm requires particle ID.Consequences for the detector design!

• pA vs Ap mode: detectors would be very different

• A-dependence: Aα

(see talk by Nora)

• ToDo (Ramona): prediction for AFTER: α vs xF


IntroductionAnalysisResults

Summary

Hadro-Production of CharmNuclear Dependence (!)

!: All beams all particles

0.6

0.65

0.7

0.75

0.8

0.85

0.9

0.95

1

1.05

1.1

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

▲

xF

αAveraged over all particles and beams

(a)

Nora Patricia Estrada Tristán alpha 32/40Tuesday, February 12, 13

IntroductionAnalysisResults

Summary

Hadro-Production of CharmNuclear Dependence (!)

!: Charm / Anti-Charm

0.6

0.65

0.7

0.75

0.8

0.85

0.9

0.95

1

1.05

1.1

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

▲

▼

xF

αCharm

AntiCharm

(b)

No difference when separating in charm and anti-charm finalstates Nora Patricia Estrada Tristán alpha 33/40


E866 Measured Open Charm and J/! vs xF

E866 also measured open charm pA dependence using single muons with pµT > 1

GeV/c (unpublished)

Di!erent from J/! for y < 0.7 but similar for higher y, suggests that dominante!ects are in the initial state

0 0.5 1 1.5 2yc.m.0.8

0.9

1

1.1

α

Open Charm - E866/NuSea (Preliminary)J/Ψ - E866/NuSeaD0 - E789

α(xF) = 0.960 ( 1-0.0519 xF - 0.338 x2F )

Figure 2: The J/! and open charm A dependence as a function of xF (Mike Leitch).

Talk by Ramona Vogt


Medium E!ects Important with Nuclear Target

Nuclear e!ects often parameterized as

!pA = !ppA! "(xF , pT )

For!

sNN " 40 GeV and xF > 0.25, " decreases strongly with xF – only low xF e!ectsprobed by SPS and RHIC rapidity coverage

Possible cold matter e!ects

• Nuclear Shadowing — initial-state e!ect on the partondistributions a!ecting total rate, important as a function of y/xF

• Energy Loss — initial-state e!ect, elastic scatterings of projectile parton beforehard scattering creating quarkonium state, need to study Drell-Yan productionto get a handle on the strength when shadowing included

• Intrinsic Charm — initial-state e!ect, if light-cone models correct, should onlycontribute to forward production, assumed to have di!erent A dependence thannormal J/# production

• Absorption — final-state e!ect, after cc that forms the J/# has been produced,pair breaks up in matter due to interactions with nucleons


Other discussions


Other discussions

• pA collisions: test region x>1

• Multiple heavy quarks; Double-charm baryonsccq, ccc, bbq, bbb

• Experimental questions


END


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