1/27/2016 R.Seidl: status of simulation1 W muon analysis in PHENIX Status of the background understanding, signal, smearing and asymmetries R.Seidl (RBRC)

PHENIX Muon Trigger Upgrade Project 2 MuID trigger (existing) selecting muon momentum > 2GeV/c MuTR FEE upgrade ( installed) fast selection of high-momentum-tracks RPC (N installed) provide timing information and rough position information μμ MuID MuTR RPC absorber PHENIX status of upgrades for run /10/2

New muon trigger system necessary 3PHENIX status of upgrades for run /10/2 simulated muons into Muon Arm (2000pb-1, with PYTHIA5.7) W dominant region current trigger (MuID) threshold σ(tot)=60mb, L=3x10 32 cm -2 s -1 (500GeV) collision rate = 18MHz (after luminosity upgrade) DAQ rate limit < 2kHz (for muon Arm) Therefore, required rejection ratio > 9000 But, MuID-trigger rejection ratio (500GeV) < 100 We need momentum dependent trigger !

RPC Upgraded Muon Trigger System 4 digitalized hit signal Level-1 trigger PHENIX status of upgrades for run /10/2 digitalized hit signal digitalized hit signal B MuTr timing information rough position information sagittaLevel-1 trigger board Level-1 RPC project MuTRG project

MuTRG installation status South Arm Completed installation during this shutdown North Arm already finished installation 2008 Summer commissioning with run9 500GeV pp data 2009/10/2 PHENIX status of upgrades for run115

RPC installation status RPC 3S module and half- octant production ramping up, installation next shutdown  Full W trigger ready for run 11 For further redundancy and offline background reduction: RPC1 and/or Absorber for run 11 or 12 1/27/2016 R.Seidl: status of simulation 6 RPC3 North: Done (thanks to PHENIX techs and BNL Riggers)!

Muon signal efficiencies and smearing 1/27/2016 R.Seidl: status of simulation 7 Wrong charge Correct charge Reconstructed Pt Pseudorapidity Momentum smearing matrix Efficiencies

Backgrounds Dominant background: low Pt hadrons decaying in muon arm W signal to background 3/1 requires rejection of 1000 Other backgrounds Punch through hadrons Other decay muons cosmics 1/27/2016 R.Seidl: status of simulation 8

Background reduction with better use of current position information Fake high Pt background reduction by Factor 10 through absorber At least Factor 100 reduction by tight cuts  Signal to background 3/1 1/27/2016 9R.Seidl: status of simulation K GeV K GeV

Run9 “W   ” analysis This run still old muon trigger, heavily prescaled Goals: confirm background yields at high momentum, check hadronic cross section in muon arms Confirm cosmics rate  Sampled muon trigger luminosity : ~0.7 pb -1  7 muons each from W decays expected Analysis is ongoing, framework for longer 500 GeV runs will be set 1/27/2016 R.Seidl: status of simulation 10

Potential improvements >run11: Forward Vertex detector Slide taken from Xiaorong Wang

Predicted RHICBOS asymmetries Large sensitivity in m - sample, Some in m + sample For real impact on sea polarization generated fake W data and perform global analysis 1/27/2016 R.Seidl: status of simulation 12

Fake data for DSSV impact analysis 1/27/2016 R.Seidl: status of simulation 13 Fake reconstructed RB asymmetries for 50 and 150 pb -1 recorded as function of eta with 40 and 50 % polarization respectively, Signal to Background ratio fixed to 3/1, no polarization uncertainty Forward  + Forward  - Backward  + Backward  - Forward  + Forward  - Backward  + Backward  -

Backward plots Luminosity, pol pdf parameterizations, polarization up for discussion Curves and data for reconstructed Pt (smearing applied to curves as well) 1/27/2016 R.Seidl: status of simulation 14

Forward plots 1/27/2016 R.Seidl: status of simulation 15

Outlook PHENIX is well prepared for the W  muon measurements in the rapidity range 1.2 < |  | < 2.2(2.4) from run11 and afterwards: Trigger capabilities ready for run 11 Additional redundancy after run 11 and Additional background reduction with FVTX 1/27/2016 R.Seidl: status of simulation 16

1/27/2016 R.Seidl: status of simulation17

So where do the MuTRG upgrades come in? Triggering: So far only 1D, in run9 prescaled by factor : 10 pb -1 become ~0.1 W yield in muon arms: a handful No prescale for MuTRG, high MuTRG efficiency (not included in plots) RPC timing: Cosmics reduction: Small time window (factor 5) Early opposite site arm veto (requires RPC1) Spin crossing information (also important for non W muon arm spin measruements, BBCs will always fire) even MuTrgFee upgrade samples over several crossings W  mu track isolation/road quality RPCs highly efficient, sampling only over one clock tick allows to reject other muon tracks  potential for isolation cuts Addition RPC3 point for muon Road, Kalman fitter improves signal quality (currently being implemented/studied by Richard Hollis) 1/27/2016 R.Seidl: status of simulation18

What do we need for the w   analaysis? Signal: Momentum Smearing, charge reconstruction Efficiencies Polarized yields (Rhicbos, Pythia, DSSV?) (offline) Backgrounds: Contributions Cut optimization Muon system Internal and relative alignment Real position resolution Reconstruction including new detectores (FVTX, MuTrg, RPC ), new variables Muon Trigger Efficiencies, turn-on curve Beam backgrounds 1/27/2016 R.Seidl: status of simulation 19

Backward plots Luminosity, pol pdf parameterizations, polarization up for discussion Curves and data for reconstructed Pt (smearing applied to curves as well) 1/27/2016 R.Seidl: status of simulation 20

Forward plots 1/27/2016 R.Seidl: status of simulation 21

Overall reconstruction efficiency and fake rate Closed symbols: correct charge efficiencies Open symbols: wrong charge Cut -1 : no cuts any charge Cut -2: no cuts right charge Cut 0: basic cuts, right charge Cut 5 : tightest cuts 1/27/ R.Seidl: status of simulation

Overall effies with cuts: absorber does not affect effies but resolution does 1/27/2016 R.Seidl: status of simulation23 Efficiencies reduced at low Pt with standard cuts (contains a 15 GeV minimal cut) Tightest cuts is severely affecting the signal have to be checked

Backgrounds: Low Pt muons from decays (abundant, reason for Trigger) High Pt muons: Fall off relatively fast High Pt punch-through hadrons: Sufficiently reduced by absorbers Fake high Pt muons (mostly low Pt kaons) Cosmic hight Pt muons Z background small, possibly nonzero asymmetry, will be included in global analysis 1/27/2016 R.Seidl: status of simulation 24

Real muon backgrounds Large amounts of decay muons from light processes as well as heavy flavor dominating at low Pt  Triggering required Yields below W yields above ~15 GeV  offline not a problem 1/27/2016 R.Seidl: status of simulation 25

High Pt Punch-through hadrons Get reconstructed at roughly at right momenta Initial yield terrifying Absorbers reduce the yield substantially Some effect of muon cuts 1/27/2016 R.Seidl: status of simulation 26

Fake high Pt background: Origin Most hadrons decay in central region or first absorbers Those surviving basic cuts decay within MuTr volume Overall and cut decay muons in Muon arms reduced by absorber (no  10cm  35 cm) 1/27/2016 R.Seidl: status of simulation 27

Cosmics (performed by GSU) Rate sounds low, but depending on RHIC luminosity this can be a substantial background Matching cosmics with other side will be important Additional timing cuts through RPCs can reduce rate further (time window and RPC1 before collision hit) Background likely to be ok 1/27/2016 R.Seidl: status of simulation 28 “ one arm cut ” Vertex cutpT cut Single muon survive cuts Rate (Hz) Yes|z|<30 cm, r<25 cmNo Yes|z|<30 cm, r<5 cmNo Yes|z|<30 cm, r<25 cm>20 GeV/c, <40 GeV/c Yes|z|<30 cm, r<5 cm>20 GeV/c, <40 GeV/c ±0.0001

Describe in detail what is and is not included in A_L simulation results Data points: Events from RHICBOS + full detector simulation + reconstruction 1.2 <  < 2.2 both arms combined Efficiencies of acceptance and reconstruction (70-80%, including charge reconstruction) Smearing of the reconstructed momentum (through simulation and reconstruction) Fixed 3 / 1 Signal to background ratio (requires absorber + tighter cuts) 70 % beam polarization 300 (1300) pb -1 on tape corresponding roughly to RHIC projections until 2013 (and RHIC-II) Generated asymmetries Events RHICBOS, 1.2 <  < 2.2 Smearing of the reconstructed momentum (performed accd. to smearing matrix in finer binning on polarized and unpolarized yields separately)