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Constraining Gluon nPDFs
Strong indications of low-x shadowing/saturation physics with d+Au J/, e- correlations, h-h correlations, single muons, electrons, …
And yet, all have final state interactions.
Golden channel direct photon
Using full statistical / systematic constraint method on EPS09 nPDFs, blue bands indicate
projected measurement (1, 2 level)
MPC-EX Direct Photon
Gluon nPDFAu Nucleus
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p+Au with transversely polarized proton
Completely unique RHIC access to saturation physics
p+Au measurement with projected uncertainties in
190 nb-1 |z|<40cm
Testing geometric scaling with Si target nuclei
Comparable uncertainties with 2 week runs
New theory developments… Transverse polarization AN in p+A scales with the saturation scale for pT < Qs
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MPC-EX UpgradeThe PHENIX MPC Crystal Calorimeter (||=3.1-3.8) has played a critical
role in our forward (low-x) and transverse spin physics program
MPC-EX upgrade adds novel silicon tracking / preshower detector to enable direct photon identification and 0 to higher momentum
Beam test in fall, and section installed for
integration tests in Run 14
Full detector available for physics in Run-15
0 rejection (prompt photons)Charged track identification0 reconstruction out to >80GeV
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Other MPC-EX measurements• Forward single-track π0
out to higher pT
• Correlations for forward-forward and mid-forward– with single-track π0’s,
prompt photons?
• Jet cluster reconstruction using MPC-EX MIPs– Assume pMIPs ~ 1 GeV/c
• Reaction plane determination with MPC and MIPs in MPC-EX
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QCD Weak Case
RHIC Perfect Fluid
Surprise: The Quark Gluon Plasma (QGP) created at RHIC is strongly coupled (sQGP) and behaves like aliquid close to the quantum mechanicallimit, not like a gas
The expected weak coupling value for/s is 1-2 orders of magnitude larger
RHIC probes the QGP near 1-2 TC
The Perfect Fluid@RHIC
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Surprise: The Quark Gluon Plasma (QGP) created at RHIC is strongly coupled (sQGP) and behaves like aliquid close to the quantum mechanicallimit, not like a gas
The theory of the QGP is not well constrained but at high T we have to move to the weakly coupled regime
The Perfect Fluid@RHIC
?
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Surprise: The Quark Gluon Plasma (QGP) created at RHIC is strongly coupled (sQGP) and behaves like aliquid close to the quantum mechanicallimit, not like a gas
The theory of the QGP is not well constrained but at high T we have to move to the weakly coupled regime
How does the Quark-Gluon Plasma transition from Strong to Weak?
Is this transition associated with changes in quasi-particles, excitations, strong fields?
The Perfect Fluid@RHIC
?
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Relating shear viscosity/entropy to the transport coefficient q
^“Small Shear Viscosity Implies
Strong Jet Quenching”A. Majumder, B. Muller, X.N. Wang, PRL (2007)
(derived for weak coupling)
s
Tq
/
25.1ˆ
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“Jet Quenching is a few times stronger near Tc relative to the
QGP at T > Tc.”Liao and Shuryak, PRL (2009)
The surprisingly transparent sQGPat the LHC [compared to RHIC]
Horowitz and Gyulassy NPA(2011)
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Stronger Coupling at RHIC?
Flow data indicate that/s is smaller at RHICThe QGP created at RHIC is more strongly coupled
What are the underlyingchanges in QGP propertiesnear the transition?
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Advantage of Hadronic Calorimetry
ATLAS and CMS heavy ion jetobservables come from
calorimeter measurements
Ability to try different methods(using tracking information)
is a big advantage
Critical to have large acceptance calorimetry with continuous coverage(no gaps,spokes, holes) to see both jets and -jet at very high rate.
Tracking information provides key additional handle for systematic studies
For measurement of fragmentation functions: hadron pT and jet energymeasures are independent
Enables triggering in p+p, p+A without jet bias
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Surface Bias EngineeringThorsten Renk has explored the ability to engineer the surface and
energy loss bias to gain more information
sPHENIX can measure these jets with no minimum pT selection and noonline trigger bias. Thus, one can explore the full range of engineered
geometries. Systematic measurements enabled “tomography”
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Surface Bias Engineering
sPHENIX can measure these jets with no minimum pT selection and noonline trigger bias. Thus, one can explore the full range of engineered
geometries. Systematic measurements enabled “tomography”
sPHENIX
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Au+Au(central 20%)
p+p d+Au
>20GeV 107 jets104 photons
106 jets103 photons
107 jets104 photons
>30GeV 106 jets103 photons
105 jets102 photons
106 jets103 photons
>40GeV 105 jets 104 jets 105 jets
>50GeV 104 jets 103 jets 104 jets
RHIC Jet RatesRHIC Jet Rates
20 weeks of running would yield 50B events, high speed daq on tape80% of dijets within || < 1
NEWSFLASH: The above numbers assume Run 11 performance. Just repeating the RHIC performance of Run14 we can sample 200 B events
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sPHENIX detectorCoverage || < 1.1
6 layer silicon tracking 3 layers refurbished from
PHENIX vtx detector
hermetic electromagnetic and hadron calorimetry
Common Silicon Photomultiplier readout and electronics for CalorimetersFull clock speed digitizers, digital information for triggering available
High data acquisition rate capability (~10kHz)
BaBar magnet 1.5 Touter HCAL provides
flux return
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Calorimeter design
HCAL: Novel tilted plate design!
Magnet 1X0
Inner HCAL 1EMCAL 18X0 1
Outer HCAL 4
Total HCal depth 5 (plus EMCAL 1)leads to few percent energy leakage for
hadrons above 50GeV comparable toother contributions to energy resolution
constant term
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EMCAL SPACAL Option
• Scintillating fiber embedded into tungsten epoxy •18 X0 deep• Moliere Radius 2.3cm cell size• Sampling fraction 2%• Resolution 12%/E• 256x96 = 24576 channels• 500pe/GeV
FNAL T-1018
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HCal:Tilted plates
sideview
• HCal absorber serves as flux return for the BaBar magnet • Straight line from vertex crosses 4 scintillators• Towersize in / 0.1 x 0.1• Prototype build and tested at FNAL• modest energy resolution requirement of 100%/E
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HCal
Tilted PlateEMCal
FNAL Test Beam Exp T-1044
Energy resolution is good enoughfor jet measurements at RHIC
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Jet studies: Fake Jet Rates
fake jets
True jets
For R=0.2 jets> 20 GeV real jetsdominate HIJING
Details in PRC86 (2012) 024908
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Jet studies: Fake Jet Rates
fake jets
True jets
for R=0.2 jets> 20 GeV real jetsdominate HIJING
Details in PRC86 (2012) 024908
for R=0.4 the lowerlimit is > 35 GeV
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Different bias for quark or gluon jets?
Quark and gluon jets have very different fragmentation functionsIntroducing pT cutoffs in the jetreconstruction (or trigger) will affect quark and gluon jets differently
sPHENIX calorimetric measurementgives the same energy scale and resolution for quark and gluon jets
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Beauty tagged jets
Substantial rate, tagged withlarge displaced vertex identifiedby inner silicon detector
Key tests of mass dependenceof radiative energy loss
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Direct photons
sPHENIX has excellent directphoton capabilities
Nature favors RHIC, in centralAu+Au collisions direct photonsdominate for pT > 20GeV/c
Simple isolation cuts with fullcalorimetry give additionalhandle and enable p+p andp+A comparison measurements
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Upsilons
Quarkonia become unbound at different temperatures depending on their radius –they are sensitive to different colorscreening lengths
Charmonium production becomes large at LHC, making directRHIC/LHC comparisons problematic
The Y(1S), Y(2S) and Y(3S) span a broad range of sizes, accessiblevia e+e- or + - and have similar cold nuclear matter effects. TheyWill not have a large coalescence contribution at RHIC or LHC.Underlying bottom production at LHC similar to charm at RHIC
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Upsilons
Quarkonia become unbound at different temperatures depending on their radius –they are sensitive to different colorscreening lengths
Charmonium production becomes large at LHC, making directRHIC/LHC comparisons problematic
The Y(1S), Y(2S) and Y(3S) span a broad range of sizes, accessiblevia e+e- or + - and have similar cold nuclear matter effects. TheyWill not have a large coalescence contribution at RHIC or LHC.Underlying bottom production at LHC similar to charm at RHIC
The points show the projectedstatistical accuracy for sPHENIX
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Summary
• RHIC probes the QGP at TC where the coupling is strongest
• sPHENIX will measure unbiased jets with full calorimetry, direct photons and upsilons
• We are on track to make this happen by 2021• The acquisition of the BaBar magnet was a game
changer – opening up the possibility to evolve into an EIC detector
2021 2025
PHENIX sPHENIX TBN@EIC
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The BaBar Solenoid Magnet The BaBar Solenoid Magnet
Ownership officially transferred to BNLBeing prepared for shipping
Dimensions:•Rinner = 140 cm
•Router – 173 cm•L = 385 cm
Field•1.5 Tesla (Nominal)•Homogeneous in center •Higher field at ends Better forward tracking
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