Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012 11 Heavy Flavor and Spin Program at Xiaorong Wang New Mexico State University Heavy Flavor workshop

Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012 11

Heavy Flavor and Spin Program

at

Xiaorong WangNew Mexico State University

Heavy Flavor workshop at UIC June 17-18, 2012


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

2 central arms: electrons

• charmonium J/, ’ ee• open charm, beauty (D,Be)

2 muon arms: muons

• “onium” J/, ’, • open charm, beauty

(D,B)

Heavy Flavor Measurement at PHENIX

e+(e-)

+(-)

GeVpT 5.0,35.0||

GeVpT 5.0,4.2||2.1

3


Silicon Vertex Detector at PHENIX

VTX (2011) and FVTX (2012)• Displaced vertex tagging of D, B decay products• Direct D reconstruction, BJ/• ’, upsilons

Silicon Tracker

D


Two Arms, Four tracking stations with full azimuthal coverage• 75 m 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


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.

Track fitting with MuTr Alignment

New trigger for open heavy flavor physics FVTX simulation and data analysis

9

FVTX Commissioning and Current Status

Radiographs from reconstructed tracks pp510U+U 200 GeV event display


Heavy Flavor SG3 trigger Development

North SG3 &&MuID South SG3 &&MuID

CuAu CuAu

SG1 Trigger: p > 15GeV for W analysisSG3 Trigger: p > 5 GeV for heavy flavorAdd 3-5 more rejection power on top of current MuID trigger


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.

8


S/B improvement for B and D with FVTX



• Drell-Yan ALL (Heavy Flavor Related) Future Forward Physics Program at PHENIX


DIS pQCD e+e-?

Study difference in particle production rates for same-helicity vs. opposite-

helicity proton collisions

-- Parton distribution functions -- Partonic hard scattering rates -- Fragmentation functions

Probing the Helicity Structure of the Nucleon

W. Vogelsang

NLO sub-process in π production

LNLN

LNLN

PPALL //

//

||

1

21

)...()ˆ(ˆ)()()(0

210 zDsxgxqXpp q

qgqg


Major impact of program Strong indication for a small gluon polarization! Next steps: Map x-dependence and extension of x-coverage

PRL 101, (2008)072001 DSSV 08

Impact of RHIC-Spin Program on Δg

best fit has a zero-crossing at x ≈ 0.1

S. Wolin DIS2012


Heavy-flavor production is leading-order gluon interactions

Heavy Flavor ALL at PHENIX

QQggLLLL a

xg

xg

xg

xgA

)(

)(

)(

)(

2

2

1

1

W. Vogelsang

NLO sub-process in π production

QQqgLLLL a

xg

xg

xq

xqA

)(

)(

)(

)(

2

2

1

1


M. StratmannK. Nakamura, PHENIX



Heavy Flavor ALL with FVTX

Heavy flavor with FVTX will allow us access small x.





Theoretical Models of TSSA (I) Transverse momentum dependent (TMD) function approach

Assuming TMD factorization….

TMD factorization is not valid for process involving more than two hadrons. T.Rogers, P Mulders, PRD81, 094006(2010)

-- Sivers mechanismD. Sivers, PR D41 (1990) 83; D43 (1991) 261

-- Collins mechanismJohn Collins, Nucl Phys B396 (1993) 161

),()( 221

kzHxqAN )(),( 2 zDkxfA hq

qTN

18


Collinear factorization approach

Twist-3 factorization works at Q >>ΛQCD,

-- 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)

Ji, Qiu, Vogelsang and Yuan

PRL 97, 082002 (2006)PRL 97, 082002 (2006)PRL 97, 082002 (2006)PRL 97, 082002 (2006)Collinear

19


Sensitive to gluon Sivers function (if it is well defined) * heavy flavor production dominated by gluon gluon fusion at RHIC * gluon has zero transversity

Sensitive to tri-gluon correlation functions

Also sensitive to J/ψ production mechanisms

Gluon Sivers function – Heavy Flavor AN


Anselmino et al, PRD 70, 074025 (2004)

Gluon Sivers=0

Gluon Sivers=Max

Calculations for D mesons

21

AN measured for muons from D decay

Not favor maximum gluon silvers.

Open Charm AN

Measurement for -

H Liu, X Wang and M Liu

V. Dharmawardane, S. Dairaku


Kang, Qiu, Yuan, Vogelsang, Phys. Rev. D 78,114013(2008)

BUP12, PHENIX





Drell-Yan simulations with FVTX

Z. You, X. Wang

Dominate background for4 < 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


BUP 12, K. Lee, X. Jiangarxive:1108.4974 (Lu, Ma, Zhu)

)(

)(

)(

)(

2

2

1

1

xu

xu

xu

xu

Sea Quark Spin TMD Functions





MuID

RICH

HCalEMCal

Tracker

EMcal

Hcal

2T Magnet

*Not to scale

27


Measurements:• Jets Energy (Sivers, CNM)• Lepton ID (DY, heavy flavor)• , K ID (Collins)• Charge ID (DY, heavy flavor,

pion and kaon asyms)• Momentum

Detector needs:• Calorimtery• Calorimetry, preshower• RICH• Tracker

• Barrel Magnetic, additional(?)

28

K. Boyle


Testing QCD: Drell-Yan AN

DIS: attractive Drell-Yan: repulsive

0.1 0.2 0.3 x

Siv

ers

Am

plitu

de

0

HERMES Sivers Results

M. DiefenthalerarXiv:0706.2242

Z. Kang and J. Qiu. Phys. Rev., D81:054020, 2010

Estimated DY AN from global Sivers fit


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.

30



Sensitive to gluon Sivers function (if it is well defined) * heavy flavor production dominated by gluon gluon fusion at RHIC

* gluon has zero transversity

Sensitive to tri-gluon correlation functions

Also sensitive to J/ψ production mechanisms

Gluon Sivers function – Heavy Flavor AN

One color-singlet diagramOne color-singlet diagram— no cancellation,

Two color-octet diagramsTwo color-octet diagrams— cancellation no asymmetry

F Yuan, PRD78, 014024(2008)


Gluon Fusion dominates at LO

PYTHIA:

Gluon polarization and ALL

Gluon Sivers function and AN

- eliminate Collions effect

33

(gg QQ ) : (qq QQ )

QQggLLLL a

xg

xg

xg

xgA

)(

)(

)(

)(

2

2

1

1


October 24, 2008

DNP2008, Xiaorong Wang

34

• very different from Light hadrons Carry most of initial quark’s energy,

pi, K, D, B..

EB ~ 80%Eb jet

From PDG


Documents

Xiaorong Wang, Heavy Flavor Workshop at UIC, June, 2012 11 Heavy Flavor and Spin Program at Xiaorong Wang New Mexico State University Heavy Flavor workshop