Silicon Vertex Upgrade for PHENIX

1
Silicon Vertex Upgrade for PHENIX

• AA from discovery to characterizing properties
  dense phase
• Need broad range of early probes charm, beauty
• pp what carries the proton spin
• DG(x) from polarized pp, over broad range in x

2
VTX Group within PHENIX
65 people, 14 Groups From USA and
Japan Brookhaven National Laboratory, Chemistry
Department,   Brookhaven National Laboratory,
Instrumentation Division,   Brookhaven National
Laboratory, Physics Department,   Florida State
University,  Iowa State University,   High Energy
Accelerator Research Organization (KEK),   Kyoto
University, Los Alamos National Laboratory,
 Niigata University,   Oak Ridge National
Laboratory, RIKEN, RIKEN BNL Research
Center  Stony Brook University,  University of
New Mexico   Proposal submitted to BNL
3
Sketch of VTX
Terms used in following physics plots
Barrel Two layers of pixels (2.5, 5cm) Two
layers of strips (10, 14cm) Endcap Four sets of
mini-strip lampshades
4
Probing Properties of Dense Matter (AuAu)
Hard-scattered partons radiate gluons gt lose
energy

• Density of color in medium
• Interference of radiated gluons from multiple
  scattering

Balance between these effects depends on mass of
quark stronger interference for heavy-quarks gt
dead-cone
Measure 1) suppression of high-pt charm 2)
Elliptic flow of charm
5
Spin Structure Function Broad Range in x (pp)
Multiple channels sensitive to gluon structure
function photonjet charm beauty Overlap,
broad range x gt Robust Dg(x)
6
Endcap extends x-range (pp)
7
VTX Enables Measurement of Displaced Vertices
B gt J/ygtmm-
D gt e
Other channels, DgtKp, Bgte
8
Additional Key Physics

• Open charm in AA is vital baseline for J/y
  suppression
• Upsilon predicted not to be suppressed gt control
  expt.
• Gluon structure function via dA
• Use knowledge of charm gt isolate thermal ee- gt
  T?
• Extend PHENIXs high-pt reach by confirming
  tracks

9
Physics Reach AuAu (514 week uptime)
RHIC-II needed for quality B measurement,
feasible U
10
Figure of Merits Baseline vs UpgradeNSAC Request

• AuAu open charm
• Current e measurement 40 systematic
• Reduce to 10 systematic
• Necessary precision for e-loss physics
• Current charm pt lt 2.5 GeV/c
• DCA c,b and DgtKp , pt to several GeV/c
• AuAu open beauty
• Not possible without upgrade
• pp spin
• Current x-range, 0.02 lt x lt 0.3, extend to 0.01 lt
  x lt 0.3
• Current one or two observables per x-range
• Extend overlap, three to four observables per
  x-range

11
VTX

• Joint Project between DOE and RIKEN-BNL, staged
  approach
• Japanese funding in place, construction started
  pixel layers
• DOE RD for outer strip layers, endcaps
• Barrel strip layers DOE proposal, submitted to
  BNL
• Endcap DOE proposal, submit in 1-2 years

12
Barrel Inner Two Pixel Layers
Japanese construction started!! ALICE1
Readout-chips bump-bonded to Pixel sensors 50x425
mm Sensors, chips summer 04 Bump-bonding
2004-2005
Validation of bump-bonding (VTT) 2D map, good
pixels
13
Barrel Outer Two Strip Layers

• Stripixel single sided, two dimensional
  read-out (Z. Li BNL Inst. Division)
• Ionization collected by two spirals
• Each spiral connects to either U or X strip
• Readout chip SVX4
• Current RD
• S/N
• board containing SVX4

14
Endcap Ministrips

• Mini-strip detectors
• 50 x 2000 to 11000 mm
• Readout chip (PHX) adapted from FPIX2 (FNAL)
• Bump bonded assemblies
• RD
• FY05 PHX design/test

PHX
15
Schedule
Calendar Years
2004 2005 2006 2007 2008 2009
Run 8
Run 9
Run 10
RD Barrel
RIKEN Construction
BNL
Proposed DOE Barrel
16
DOE Costs Per Year
17
Summary

• Heavy quark probes of early stage of AuAu
• Stronger gluon interference gt smaller
  energy-loss
• Baseline for suppression (J/y) / (open charm)
• Gluon spin-structure function in pp
• Broad-coverage in x
• Overlap in x gt robust global fits
• Japan construction of pixel layers underway
• RD finishing for strip layers
• RD in progress for endcaps

18
Backups
19
Direct Observation of Open Charm and Beauty
e,m
X
Detection of decay vertex will allow a clean
identifications of charm and bottom decays
D
Au
Au
m ct GeV mm D0
1865 125 D 1869 317 B0
5279 464 B 5279 496

D
B
J/?
p
K
X
e
e

• Detection options (PHENIX)
• Beauty and low pT charm via displaced e and/or m
  -2.7lthlt-1.2 , hlt0.35 , 2.7lthlt1.2
• Beauty through displaced J/? ? ee (mm)
  -2.7lthlt-1.2 , hlt0.35 , 2.7lthlt1.2
• High pT charm through D ? ? K hlt0.35

20
Rate Assumptions

• AuAu zlt10cm, 514 week, RHIC 60, PHENIX 60
• RHIC I, Integrated DAQ 0.76 pb 1
• RHIC II, Integrated DAQ 7.6 pb 1
• 50 MB, 50 LVL1 triggers
• Trigger electron threshold increased for RHIC-II

21
(J/y) / charm
22
pA Physics with VTX

• Extracting gluon structure function in nuclei,
  shadowing

23
Spectra
24
Upsilon Spectroscopy with RHIC II Luminosity

• Muon arms
• Central arms

total of 400 ? ? µµ reconstructed
decays north muon arm sm 190 MeV south
muon arm sm 240 MeV
total of 150 ? ? ee decays reconstructed
original setup sm 170 MeV upgraded setup
sm 60 MeV
25
Low-Mass ee- Pairs Prospects at RHIC
Sensitive to chiral symmetry restoration
R. Rapp nucl-th/0204003
Strong enhancement of low-mass pairs persists
at RHIC
Need Dalitz rejection accurate charm
measurement
Significant contribution from open charm