Transcript Slide 1

Heavy Flavor and Spin Program
at
Xiaorong Wang
New Mexico State University
Heavy Flavor workshop at UIC
June 17-18, 2012
Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012
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Heavy Flavor measurement at PHENIX
 Gluon Spin in the Proton (ΔG)
 Transverse Spin Physics
 Flavor Separated Sea Quark Spin
• Drell-Yan ALL (heavy flavor related)
 Future Forward Physics Program at PHENIX

Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012
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Heavy Flavor Measurement at PHENIX
e+(e-)
2 central arms: electrons
|  |0.35, pT > 0.5GeV
• charmonium J/, ’ -> e+e
• open charm, beauty (D,Be)
m+(m-)
2 muon arms: muons
1.2 |  | 2.4, pT > 0.5GeV
• “onium” J/, ’,  -> m+m• open charm, beauty
(D,Bm)
Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012
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Silicon Vertex Detector at PHENIX
VTX (2011) and FVTX (2012)
• Displaced vertex tagging of D, B decay products
• Direct D reconstruction, BJ/
• ’, upsilons
Dm
m
Silicon Tracker
m

Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012
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Two Arms, Four tracking stations with full azimuthal coverage
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•
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75 mm pitch strips in radial direction, 3.75° staggered phi strips
Radiation length < 2.4%/wedge to minimize multiple scattering
Outer Support and Cooling outside active area
Kapton cable plant primarily outside active area
Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012
FVTX Commissioning and Current Status
Summary of FVTX Status in 2012
Over 90% of Detector is operational and Detector
performance design specifications have been met.
 Software are tuning with real data.
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 Track fitting with MuTr
 Alignment
New trigger for open heavy flavor physics
 FVTX simulation and data analysis
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Radiographs from reconstructed tracks pp510
U+U 200 GeV event display
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Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012
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Heavy Flavor SG3 trigger Development
SG1 Trigger: p > 15GeV for W analysis
SG3 Trigger: p > 5 GeV for heavy flavor
Add 3-5 more rejection power on top of current MuID trigger
North SG3 &&MuID
South SG3 &&MuID
CuAu
Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012
CuAu
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The challenge: backgrounds ( ->μ and K-> μ) overwhelm the signal.
 Flying distance and decay angle are different. Get DCA components in r
(higher resolution) and phi (moderate resolution).
 Significant improvement in angular resolution of track leading to dimuons
mass resolution
 Track isolation cut will suppress hadrons from jet for W measurement
 Joint tracking with MuTr. Track χ2 cut will discriminate muon from hadron
background.
Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012
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S/B improvement for B and D with FVTX
Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012
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Heavy Flavor measurement at PHENIX
 Gluon Spin in the Proton (ΔG)
 Transverse Spin Physics
 Flavor Separated Sea Quark Spin
• Drell-Yan ALL (Heavy Flavor Related)
 Future Forward Physics Program at PHENIX

Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012
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Probing the Helicity Structure of the Nucleon
ALL 

1 N + + / L+ + - N + - / L+ 
 | P1 P2 | N + + / L+ + + N + - / L+ -
Study difference in particle production
rates for same-helicity vs. oppositehelicity proton collisions
  ( pp   X )   q ( x1 )   g ( x 2 )   ˆ
0
?
DIS
qg  qg
0
q
( sˆ )  D ( z )...
pQCD
e+e-
NLO sub-process in π production
-- Parton distribution functions
-- Partonic hard scattering rates
-- Fragmentation functions
W. VogelsangXiaorong Wang,
Heavy Flavor Workshop at UIC, June, 2012
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Impact of RHIC-Spin Program on Δg
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Major impact of program
Strong indication for a small gluon polarization!
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Next steps:
Map x-dependence and extension of x-coverage
PRL 101, (2008)072001 DSSV 08
S. Wolin DIS2012
best fit has a zero-crossing at x ≈ 0.1
Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012
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Heavy Flavor ALL at PHENIX
Heavy-flavor production is leading-order gluon interactions
NLO sub-process in π production
W. Vogelsang
g ( x1 ) g ( x2 ) gg QQ
ALL 
aLL
g ( x1 ) g ( x2 )
q( x1 ) g ( x2 ) qg QQ
ALL 
aLL
q( x1 ) g ( x2 )
Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012
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K. Nakamura, PHENIX
M. Stratmann
Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012
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Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012
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Heavy Flavor ALL with FVTX
Heavy flavor with FVTX will allow us access small x.
Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012
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Heavy Flavor measurement at PHENIX
 Gluon Spin in the Proton (ΔG)
 Transverse Spin Physics
 Flavor Separated Sea Quark Spin
• Drell-Yan ALL (Heavy Flavor Related)
 Future Forward Physics Program at PHENIX
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Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012
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Theoretical Models of TSSA (I)
 Transverse momentum dependent (TMD) function approach
Assuming TMD factorization….
-- Sivers mechanism
D. Sivers, PR D41 (1990) 83; D43 (1991) 261
AN  fTq ( x, k2 )  Dqh ( z)
-- Collins mechanism
John Collins, Nucl Phys B396 (1993) 161
AN  q( x)  H1 ( z2 , k 2 )
TMD factorization is not valid for process involving more than two hadrons.
T.Rogers, P Mulders, PRD81, 094006(2010)
Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012
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Collinear factorization approach
Twist-3 factorization works at Q >>ΛQCD,
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-- Twist-3 quark-gluon correlation function TqF
-- Two independent tri-gluon correlation functions TG( f ) and TG( d )
 TMDs and Collinear Twist-3 Functions
In the overlap region both approaches give the same physics (Drell-Yan)
PRL 97, 082002 (2006)
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Q2, qT2 >> LQCD
Collinear
Ji, Qiu, Vogelsang and Yuan
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Q2 >> qT2 >> LQCD
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Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012
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Gluon Sivers function – Heavy Flavor AN
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Sensitive to gluon Sivers function (if it is well defined)
* heavy flavor production dominated
by gluon gluon fusion at RHIC
* gluon has zero transversity
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Sensitive to tri-gluon correlation functions
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Also sensitive to J/ψ production mechanisms
Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012
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Open Charm AN
Gluon Sivers=Max
 AN measured for muons from D decay
 Not favor maximum gluon silvers.
Gluon Sivers=0
V. Dharmawardane, S. Dairaku
Calculations for D mesons
Anselmino et al, PRD 70, 074025 (2004)
H Liu, X Wang and M Liu
Measurement for m-
Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012
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Kang, Qiu, Yuan, Vogelsang, Phys. Rev. D 78,114013(2008)
D0 ® m + + X
D0 ® m - + X
BUP12, PHENIX
Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012
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Heavy Flavor measurement at PHENIX
 Gluon Spin in the Proton (ΔG)
 Transverse Spin Physics
 Flavor Separated Sea Quark Spin
• Drell-Yan ALL (Heavy Flavor Related)
 Future Forward Physics Program at PHENIX

Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012
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Drell-Yan simulations with FVTX
Z. You, X. Wang
 Dominate background for
4 < mass 10 GeV is b-bbar
 Full PYTHIA+PISA
simulations for bbar and
Drell-Yan with FVTX
 Study background rejection
with FVTX In Drell-Yan
process
Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012
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Sea Quark Spin
BUP 12, K. Lee, X. Jiang
-
TMD Functions
arxive:1108.4974 (Lu, Ma, Zhu)
u ( x1 ) u ( x2 )

u ( x1 )
u ( x2 )
Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012
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Heavy Flavor measurement at PHENIX
 Gluon Spin in the Proton (ΔG)
 Transverse Spin Physics
 Flavor Separated Sea Quark Spin
• Drell-Yan ALL (Heavy Flavor Related)
 Future Forward Physics Program at PHENIX

Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012
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Tracker
EMcal
Hcal
2T Magnet
RICH
EMCal
*Not
to scale
Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012
HCal MuID
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K. Boyle
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Measurements:
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Jets Energy (Sivers, CNM)
Lepton ID (DY, heavy flavor)
, K ID (Collins)
Charge ID (DY, heavy flavor,
pion and kaon asyms)
• Momentum
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Detector needs:
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Calorimtery
Calorimetry, preshower
RICH
Tracker
• Barrel Magnetic, additional(?)
Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012
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Testing QCD: Drell-Yan AN
Sivers Amplitude
DIS: attractive
HERMES Sivers Results
Drell-Yan: repulsive
Estimated DY AN from global Sivers fit
M. Diefenthaler
arXiv:0706.2242
0
0.1 0.2 0.3 x
Z. Kang and J. Qiu. Phys. Rev., D81:054020, 2010
Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012
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Heavy flavor is unique channel to understand gluon polarization
and gluon Sivers.
PHENIX has measured single electron longitudinal double spin
asymmetry to understand ΔG.
PHENIX has measured heavy flavor transverse single spin
asymmetry to understand gluon Sivers.
Newly installed FVTX detector has successfully commissioned
into PHENIX data taking. New heavy flavor trigger (SG3) is
implemented. Good efficiency and rejection achieved low p > 5
GeV single muons.
Heavy flavor spin physics are coming soon.
Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012
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Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012
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Gluon Sivers function – Heavy Flavor AN
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Sensitive to gluon Sivers function (if it is well defined)
* heavy flavor production dominated by gluon gluon fusion at RHIC
* gluon has zero transversity
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Sensitive to tri-gluon correlation functions
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Also sensitive to J/ψ production mechanisms
F Yuan, PRD78, 014024(2008)
One color-singlet diagram
— no cancellation,
Two color-octet diagrams
— cancellation no asymmetry
Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012
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
Gluon Fusion dominates at LO
PYTHIA:
 (gg  QQ ) :  (qq  QQ )

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Gluon polarization and ALL
g ( x1 ) g ( x2 ) gg QQ
ALL 
aLL
g ( x1 ) g ( x2 )
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Gluon Sivers function and AN
- eliminate Collions effect
Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012
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October 24, 2008
From PDG
• very different from Light hadrons
Carry most of initial quark’s energy,
E B ~ 80% E b- jet
pi, K, D, B..

DNP2008, Xiaorong Wang
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Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012
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Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012
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