html5-img
1 / 33

a FO rward CAL orimeter

a FO rward CAL orimeter. Overview. Richard Seto Winter Workshop on Nuclear Dynamics Feb 7, 2009. NSAC milestones – Physics Goals. pA physics – nuclear gluon pdf.  G. -Jet AuAu. transverse spin phenomena. Look for saturation effects at low x

sarai
Télécharger la présentation

a FO rward CAL orimeter

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. a FOrward CALorimeter Overview Richard Seto Winter Workshop on Nuclear Dynamics Feb 7, 2009

  2. NSAC milestones – Physics Goals pA physics – nuclear gluon pdf  G -Jet AuAu transverse spin phenomena

  3. Look for saturation effects at low x Measure initial state of Heavy Ion Collision measure gluon PDF’s in nuclei! (DM8) x pA physics – nuclear gluon pdf Saturation at low x Nuclear Gluon PDF’s : DM8 xG(x) direct  jets –x resolution forward η(low-x)

  4. Longitudinal Spin G, g(x) : HP12 • What is the gluon contribution to the proton spin. Is it at low-x? • Phenix and STAR have put constraints on G

  5. x Longitudinal Spin G, g(x) : HP12 DSSV finds • g(x) very small at medium x (even compared to GRSV or DNS) • best fit has a node at x ~ 0.1 • huge uncertainties at small x Current data is sensitive to G for xgluon= 0.020.3 EXTEND MEASUREMENTS TO LOW x! Forward Measure x RHIC range 0.05· x · 0.2 small-x 0.001· x · 0.05 direct  jets –x resolution forward η(low-x) 0 0

  6. use -jet to measure Sivers Use 0 in jet to measure Collins determination of the process dependence of the Sivers effect in g+jet events So what does Sivers tell us about orbital angular momentum? Major new Thrust Transverse Spin Phenomena: HP13 Sivers direct  -jet 0 forward η(low-x) large η coverage

  7. Study the medium via long range correlations with jets are these correlations from a response by the medium? “jet” “ridge” STAR Preliminary Correlations with jets in heavy Ion collisions: DM10 for example ? leading EM shower EM - shower large η coverage Jet correlations in AuAu

  8. direct  and electromagnetic showers jet angles to obtain x2 0 s forward  to reach low-x has large  coverage To meet these goals we must have a detector that measures: now what do we build?

  9. Central Arms ||<0.3 Tracking PbSc/PbGl(EMC) PID VTX to come Muon arms 1.1<||<2.4 magnet tracking -ID FVTX to come Schematic of PHENIX central magnet MPC 3<||<4 calorimetry

  10. Perfect space for FOCAL! (but tight!) 40 cm from Vertex FOCAL • EM bricks • 14 HAD bricks • HAD behind EM 20 cm of space nosecone

  11. FOCAL Requirements • Ability to measure photons and π0’s to 30 GeV • Energy resolution < 25%/E • Compact (20 cm depth) • Ability to identify EM/hadronic activity • Jet angular measurement • High granularity ~ similar to central arms • small mollier radius ~1.4 cm • large acceptance – rapidity coverage x2 ~ 0.001 • Densest calorimeter -> Si W We wanted large  coverage what sort of coverage if we put a detector where the nosecones are?

  12. FOCAL FOCAL Muon tracking Muon tracking VTX & FVTX FOCAL a large acceptance calorimeter tracking EMC 0 f coverage 2p tracking EMC MPC MPC -3 -2 -1 0 1 2 3 rapidity What’s missing? FORward CALorimetery

  13. reach in x2 for g(x) and GA(x) log(x2) EMC+VTX EMC+VTX+FOCAL EMC+VTX+FOCAL+MPC X2  10-3

  14. FOCAL Design

  15. Overall Detector – stack the bricks “brick” supertower 6cm 17 cm 6cm 85 cm Note this ledge may not be in the final design

  16. Pads Silicon Design Design Tungsten-Silicon Pads: 21 layers • 535 m silicon • 16 cells: 15.5mmx15.5mm X and Y Strips: 4 layers • x-y high resolution strip planes • 128 strips: 6.2cmx0.5mm γ/π0 Discriminator=EM0 segments= EM1 EM2 Supertower Particle Direction 6cm 4 planes of x-y “strips” (8 physical planes) 4 mm W Silicon “pads”

  17. Vital statistics • EM0= /0, EM1, EM2 segments • ~17 cm in length • 22 X0 ~ 0.9 • Strips – read out by SVX-4 • 8 layer *128 strips=1024 strips/super-tower • 1024 strips/super-tower*160 super-towers/side = 163,840 strips/side • 163840 strips/side (1detector/128 strips) = 1280 Strip Detectors/side • 163,840 strips /(128 channels/chip)= 1280 chips/side • Pads – read out by ADC– 3 longitudinal readouts • 160 supertowers/side*21 detectors/supertower= • 3360 Si pad detectors/side • 3360 detector*16channels/detector= 53760 pads/side • readout channels (pads) • 160 supe-rtowers/side *16 pads/tower*3 towers =7680 readouts/side • Bricks • 2x4 supertowers: 4 • 2x6 supertowers: 6 • 2x7 supertowers: 4

  18. Detection – how it works Some detector performance examples

  19. Status of simulations • Stand alone done w/ GEANT3/G4 to study • /0 separation, single track 0 (G4) • EM shower energy/angle resolutions (G4) • Full PISA • jet resolution (G3/PISA) • 2 track 0 (G3/PISA) • Several levels • Statistical errors, backgrounds, resolutions folded into Pythia level calculations • Full PISA simulation using old configuration • Transverse spin physics – task force formed – simulations in progress (early step is to put models etc into simulations) *PISA – PHENIX Geant3 simulation

  20. vertex It’s a tracking device A 10 GeV photon “track” EM2 EM0 EM1 Pixel-like tracking: 3 layers + vertex Each “hit” is the center of gravity of the cluster in the segment Iterative pattern recognition algorithm uses a parameterization of the shower shape for energy sharing among clusters in a segment and among tracks in the calorimeter.

  21. Energy Resolution (Geant4) New Geometry Excludes Strips no sampling fraction correction 0.00+0.20/√E adequate: we wanted ~ 0.25/√E

  22. /0 identification: pp 2 track 0 pT<5 GeV E=6-10 GeV pt=2.-2.5 y=1-1.5 pt=1.-1.5 y=1-1.5 pt=4.-4.5 y=1-1.5 pt=1.5-2.0 y=1.5-2.0 pt=0.5-1.0 y=2-2.5 pt=0.5-1.0 y=1.5-2.0

  23. /0 identification:Single track /0 50 GeV pi0 • for pt>5 GeV • showers overlap • use x/y + vertex to get opening angle • Energy from Calorimeter • Energy Asymmetry – assume 50-50 split as a first algorithm X-view 4-x, 2x Y-view 4-y, 3y invariant mass

  24. 10 GeV h~1.65 (Geant4-pp events) Assumed g region Assumed p0 region  0 • /0 identification: single track /0 • tested at various energies and angles, so far at pp multiplicities Fake g reconstruction: 20% Real p0 reconstruction: 50-60% Real g reconstruction: ~ 60% Fake p0 reconstruction ~ 5%

  25. Longitudinal Spin G, g(x) : HP12 GSC, Response + Background ALL 150/pb, P=0.7 RHIC region FOCAL Direct Gamma ALL next step: use -jet to constrain x

  26. GSC DSSV Selecting x with rapidity cuts 0 0 • Use 0 as a stand in for jets and do a correlation • require 1st 0 pT>2.5 GeV, =1-3 (into focal) • Choose 2nd 0 to be opposite side in  and  to go to low x2 log(x2) (2nd 0) Longitudinal Spin Goal

  27. q Compton g q  q Annihilation g q unknown “Direct” Constraint of G(x) in Nuclei:DM8 Valence Gluon Sea Eskola et al, JHEP0807:102,2008 hep-ph/0802.0139 • G(x) in nuclei almost unconstrained at low x • Proposal: Measure -jet in d+Au collisions to extract G(x) in nuclei

  28. x2~ resolution 15% Resolutions • EM shower • energy – 20%/E • angular – 6mr • Jet angular resolution • 60 mr @ pt=20 GeV jet angular resolution pT Full PISA simulation

  29. Expected Error for GA(x)/Gp(x) :DM8 pT jet>4 GeV, ptgamma>2 d+Au: Ldt = 0.45 pb -1 x 0.25 eff p+p: Ldt = 240 pb-1 x 0.25 eff G(x)Au/G(x)p Current uncertainty Log(x2) • Possibility for a dramatic improvement in understanding of G(x) in nuclei • Impact is widespread • Errors are statistical only

  30. “jet” leading particle hadrons leading particle suppressed “ridge” hadrons q q q q STAR Preliminary hadrons hadrons leading particle leading particle suppressed Studying the medium through jet “tomography”DM10 pTtrig>2.5 GeV/c, pTassoc > 20 MeV/c, Au+Au 0-30% jet ridge E. Wenger (PHOBOS), QM2008

  31. Jet correlation studies with the FoCalDM10 • Need • higher-pT triggers, • Extended  reach • large  • How: • trigger on high-energy g in FoCal • study associated particles in central and muon arms • What: • Extended h reach and Dh range (~6) • Study particle composition of correlated particles using central/muon arm PID detectors including photons • Heavy-quark studies via leptons in central/muon arms

  32. Parameterize background by studying average energy deposited in the detector (E) and its fluctuations (RMS) Study efficiency and contamination for set values of Nσ E ERMS Strategy: /0 trigger eff, AuAu b=3.2 fm =[1.,1.5] Ecut> ~15 GeV background assuming pp high pt rates S:B~10:1 /0 trigger eff high pT em shower embedded in hijing

  33. Conclusion • We want to address the following NSAC milestones • measure G at low-x to see if the gluon contributes to the proton spin • measure the nuclear gluon pdf’s • to study the effects of transverse spin and its connection to the orbital angular momentum of the constituents of the proton • Study long range correlations between jets and secondary particles as a means to understand the medium created in heavy ion collisions at RHIC • These goals can addressed by calorimeter which • can identify and measure s and 0 • can measure the jet angular resolution and together with the information from the  can lead to a reasonable measurement of x2 • has large rapidity coverage and can probe x2  10-3 • We now have a have design • Prototype in April

More Related