DY at STARfor decadal plan (run15-20)

Akio Ogawa

1

DY

2

DY : ~7 x 10-5 mb @ 500GeV

Hadronic : ~30mb 106

Hadron & photon backgroundsCharm & bottom backgrounds

Need >100 Billion hadronic events to simulate backgrounds

PHENIX Muon ArmEta = 1-2

DY Charm Bottom

http://spin.riken.bnl.gov/rsc/write-up/dy_final.pdf

STAR forward detectors

3

≈ 6 Lint spaghetti calorimeter10cm x 10cm x 120 cm “cells”

DX shell R ~ 60cm

Proposed FHC(for jet & lambda)

FMSIn open position

x~50cm from beam

No space for FHC near beamNo space in front of FMS neither

FTPC (to be removed next year)

DY signal

Everything >2

FMS closed(FHC cannot be placed dueTo DX magnet)

FMS open (x=50cm)+ FHC (x=60cm)

pythia6.222, p+p @ sqrts=500DY process, 4M events/6.7E-05mb ~ 60/pbe+/e- energy>10GeV & >2xF>0.1 (25GeV)4GeV < invariant mass < 10GeV

Inv Mass E pT

14799 events

6512 events

1436 events(1/5 from closed)

4

(direct) b backgroundpythia6.222, p+p @ sqrts=500DY process, 4M events / 6.7E-05mb ~ 60/pbB production, 300M events / 5.2E-03mb ~ 58/pb(Fragmentation b need 180B events / 30mb ~ 60/pb)

FMS closed : small at high xF & high eta & mostly unlike sign

Inv Mass E pT

DYDirect B Direct B unlikeDirect B like

FMS closed

e+/e- energy>10GeV & >2xF>0.1 (25GeV)4GeV < invariant mass < 10GeV

5

(direct) b background

Everything >2 FMS closedFMS open (x=50cm)+ FHC (x=60cm)

Electron/position radius from beam at FMS

DYDirect B

e+/e- energy>10GeV & >2xF>0.1 (25GeV)4GeV < invariant mass < 10GeV

pythia6.222, p+p @ sqrts=500DY process, 4M events / 6.7E-05mb ~ 60/pbB production, 300M events / 5.2E-03mb ~ 58/pb(Fragmentation b need 180B events / 30mb ~ 60/pb)

FMS closed : small at high xF & high eta & mostly unlike sign FMS opened + FHC : significant @ low xF & small eta(even smaller eta/phenix muon arm : b > DY) 6

High xF DY @ STAR needs• High > 4 coverage• Additional e/Hadron separation

– hadron suppression > 1/1000 per hadron

• Additional e/Gamma separation (incl gamma->e+e-) – gamma suppression > 1/1000 per gamma

• Forward tracking for charge like/unlike sign (?)• Significant trigger upgrades

– FMS with localized hadron & neutral veto

• Extension of west platform

7

DY @ STAR for decadal planrun15-20

1) FFGT + Pre-Showers/Tracker/SMD + Shorter Ecal (PbW) + Hcal + removal of west platform

2) FFGT + Pre-showers/TRD/Tracker/SMD + FMS (fill 20cm x 20cm hole around beam pipe?) + extension of west platform

8

e/Hadron separation

• Trigger & offline– FMS (rarely measure full hadron energy)– FMS + FHC veto (1/10 – 1/1000 depends on energy)

No space for ecal + hcal at eta=4 between DX & poletip holder– Pb Converter + Early-shower detector (~1/10) – Electron-ID like TRD or TR-Tracker (1/10 – 1/100)

• Offline– E(FMS)/p(tracking) Hard to measure p well at high xF with STAR magnet– FMS (or FMS-SMD) shower shape analysis (Need study)

9

EM calorimeter…

• 2500 PbWO crystals

• APD readout

• 1264 lead glass

• PMT readout

hadron calorimeter…

• 1400 towers (Atlas)

wheel/spoke support for DX and hadron calorimeter

DX

Wide Angle Hall Floor

Concept for forward

EM+hadron calorimeter at

STAR

Existing west side of Wide Angle Hall

3/27/1010

HjC - STAR@BNL

H. Crawford/L. Bland

• Cherenkov – Beta(pion) @ 1GeV 0.99– Beta(pion) @ 3GeV 0.999– air 1/n 0.99970 – hydrogen 1/n 0.99986– Beta(pion) @ 10GeV 0.9999– Beta(pion) @ 30GeV 0.99999– Beta(electron) @ 1GeV 0.9999999

• Transition Radiation Detector (TRD)– ALICE http://www-alice.gsi.de/trd/transp/andronic07.pdf– AMS http://cyclo.mit.edu/~bmonreal/trd.html– HERMES http://hermes.desy.de/notes/pub/96-LIB/thiessen.96.028.ps.gz

Electron PID (hadron rejection)

11

TRD

12

1 layer (out of 20 layers) AMS TRDhttp://cyclo.mit.edu/~bmonreal/trd.html

HERMES TRD Performance http://hermes.desy.de/notes/pub/96-LIB/thiessen.96.028.ps.gz

Electrons/positrons emit X-raysWhich are detected in Xe/CO2 gasdetector, in addition to normal ionization

13http://www-alice.gsi.de/trd/transp/andronic07.pdf

e/Gamma separation • Trigger & offline

– Neutral veto in Pre-Shower detector (~1/100)– Gamma->e+e- conversion in beam pipe

• Pre-shower with 2MIP/e+e- conversion pair veto (~1/100?)– Gamma->e+e- conversion in preshower (~1/2)

• Small radiation length in preshower (or 1st tracking station) desired

– Thin Pre-Shower detector with good resolution to do 0mip - 1mip - 2mip separation

• Offline – Reconstructing pi0 (and eta) and removing them in FMS ( ~ 1/10)– Tracking to resolve single electron to pair (? Need study)

14

Red foils: H/V traces

Blue foils: Diag traces

GEM based Pre-shower & Early-shower detectors

Pre-shower 0.3mm – 0.9mm pitch 55k channels

~2RL Pb Converter

Early-shower 2mm -3mm pitch 11k channel

Total 66k channels

Carl Gagliardi

Charge like/unlike sign

• Charge like/unlike sign separation needed?• If so, STAR solenoid enough?• Or need forward dipole magnet? • Tracking

– FGT with small R + a couple more rings ?– Another tracker at FMS (pre-shower or SMD) ?

• Momentum resolution for E/p ?• c/b tag ?

16

STAR Magnetic Field

• Radial and Azimuthal fields impart impulses in the Φ direction and partially cancel

Chris QM09 talk : http://drupal.star.bnl.gov/STAR/files/QM2009_Perkins_v5_0.ppt

€

Δϕ =c( Bz∫ dr − Br∫ dz)

Pr

≈c

Pr

(0.5T⋅Pr

Pz

4m −3.5

0.4

Pr

Pz

0.1T⋅1m)

≈0.6 − 0.26[radian]

Pz[GeV ]≈

0.34[radian]

Pz[GeV ]17

Run8 FMS-FTPC (Jim Drachenberg)http://www.star.bnl.gov/protected/spin/drach/Run8FMS/FMS-FTPC_correlation/

ΔΦ = 0.1 Δz/pz (Δz=2.5m) = 0.25 radian / GeV For 10GeV at y=0 @ FMSΔy @ x=20cm = 0.5cmΔy @ x=40cm = 1.0cmΔy @ x=80cm = 2.0cm

For 50GeV at y=0 @ FMS Δy @ x=20cm = 0.1cmΔy @ x=40cm = 0.2cmΔy @ x=80cm = 0.4cm

FTPC+FMS have done chargeseparation with STAR magnet at 2.8<<3.8 E ~ 10GeV

18

19

(FTPC)

FGT extension?

20

4

3

2

J. Balewski/MIT

Dipole Analysis Magnet ConceptPresent RHIC Interaction Regions

Conceptual Plan to Allow DXA

• reduce field strengths in D0,DX

• move DX towards IP

Forward DY Interaction Region

if charge sign required

• DXA used for beams and for DY daughters

3/27/1021

HjC - STAR@BNL

H. Crawford/L. Bland

DY @ STAR for decadal planrun15-20

1) FFGT + Pre-Showers/Tracker/SMD + Shorter Ecal (PbW) + Hcal + removal of west platfrom ~ 10 M$ ??

2) FFGT + Pre-showers/TRD/Tracker/SMD + FMS (fill 20cm x 20cm hole around beam pipe?) + extension of west platform ~ 5M$ ??

22

backup

23

Some documents

• Updated FHC proposalhttp://hena.lbl.gov/FMS/docs/hcal_proposal_update_091001.pdf

• Hank's FHC talk at STAR upgrade meetinghttp://drupal.star.bnl.gov/STAR/system/files/FHC_091217.pdf

• DY paper (2007)http://spin.riken.bnl.gov/rsc/write-up/dy_final.pdf

24

25

Simple QEDexample:

DIS: attractive Drell-Yan: repulsiveSame in QCD:

As a result:

Attractive vs Repulsive Sivers EffectsUnique Prediction of Gauge Theory !

26 0.1 0.2 0.3 x

Siv

ers

Am

plitu

de

0

0

HERMES Sivers Results RHIC II Drell Yan Projections

Markus DiefenthalerDIS WorkshopMűnchen, April 2007

DOE HP13 milestone“Test unique QCD predictions for relations between single-transverse spin phenomena

in p+p scattering and those observed in deep-inelastic lepton scattering” with an estimated completion of 2015”

Attractive vs Repulsive Sivers Effects

27

28