Precision Beam Position Measurements for Drell-Yan TSSA Studies

Beam position and angular direction measurements 4/1/2015 Two sets of position-sensitive diamond detector ~2cm apart, better than 1mm spatial resolution Quadrant Pattern (X,Y) and sigma MC PYTHIA Sim MB to check rates Optimal detector locations 4/12/2025 Ming Liu 1

E906 Beam Line Layout Dave K. 4/12/2025 Ming Liu 2

How to Measure Drell-Yan TSSA Raw Asymmetry at 10^-3 Level with a polarized proton target? 3/2015 The challenges of precision TSSA measurements Detector acceptance * efficiency varies >>1% level over a few hours of operation under a given target polarization configuration Very difficult to measure the relative beam on target(NH3) luminosity at ~10^-3 level Large beam x-y profile small target size Beam position/direction jitter (dX ~ 1-2mm), see https://p25ext.lanl.gov/elog/Hardware/12 non-uniform DC responses to large beam intensity fluctuations (~O(10%)) NH3 packing factor variation >~1% from target to target Target polarization known to ~O(3-4%) level through NMR Other variations, including target changes etc, ~O(1%) Frequent spin flip is hard/impossible can t do what we are doing at RHIC and Jlab Takes time to reach a stable polarization We must be able to measure raw TSSA at 10^-3 level for a given target polarization configuration A new approach needed 4/12/2025 Ming Liu 3

The Normal Approach in collider-mode: RHIC, JLab etc. Spin UP(1) and DOWN(2): A = <pol>*physics asymmetry, ~O(1%) Relative luminosity, for E1039, this is the luminosity of beam on target, which is very hard to measure to <<(0.1%)! Need precision measurements of relative luminosity, better than ~O(0.1%) 4/12/2025 Ming Liu 4

Reality: Not So Perfect Detector and Beam Controls Not so perfect detectors (dt ~ minutes) without fast spin flip (dT << minutes) Polarized target spin-flip period ~ several hours Acceptance varies within the time of a fixed target spin config. Time dependence Dead and hot space points Impossible to get to << O(0.1%) If target is not a pure proton, for e.g. NH3, another background fraction fB , including all other supporting materials, Target and time- dependent Background fraction: Varies target to target Target variation DY events produced in Target (space,time ) variation 4/12/2025 Ming Liu 5

False Detector Asymmetry Study Run-2 data dimuons (Roadset 57) Event selection: 4< mass < 7 Target events: -250 < z0 < -50cm Beam dump events: -50 < z0 < 200 cm Track quality cuts Detector (relative) acceptance for DY events Raw spin asymmetries MC study need to correct target/beam dump acceptance difference Trigger road bias Detector acceptance corrections Further reduce raw asymmetry via target spin-flip and Fmag/kMag field directions Keep the same target dipole field , only change RF frequency to flip the direction of target polarization Change the FMag and kMag field directions Impact of Relative beam on target beam luminosity 4/12/2025 Ming Liu 6

Run-2: Close Look of DY Phi Distributions We need to get the false asymmetry << 0.1% ~ expected raw spin asymmetry A = 0.171 +/- 0.013 -- 100x too large! Huge false asymmetry: >> X10 sigma 4/12/2025 Ming Liu 7

A New Approach Using the same DY events from beam dump to normalize the detector acceptance effects Beam dump events, 100x statistics, similar muon acceptance the stat_err from reference << signal stat_err the beam dump asymmetry = 0 Known physics normalize the beam intensity Can achieve O(1%) on relative luminosity of beam on target, with dedicated telescopes Identical timing and spatial variation of detector acceptance and efficiency for signal and background Can achieve O(0.1%) on raw asymmetry False asymmetry after normalization: ~ 1 sigma, good! Need to run ~100x more MC or data to prove we can reach 0.001 level! 4/12/2025 Ming Liu 8

If we use the same DY dimuon events (mass, pT,xF etc) from Target and Dump: How it works? - the time-dependent detector acceptance variations are mostly canceled out The small difference can be corrected with MC and data by using the muons measured in the same phase space Much reduced requirements on relative lumi, background fraction, target polarization measurements - sufficient at O(1%) level. dNT arget(f)= N1+N2(1+P A cos(f)) = NT arget (fB+(1- fB)(1+P A cos(f))) e(f,t) 0 - dNDump(f)= NDump e(f,t) 0 - N1 fB N1+ N2 4/12/2025 Ming Liu 9

Run-2 DY Dimuon (Roadset 57): all targets 10000 12000 2000 4000 6000 8000 1000 1200 1000 1200 200 400 600 800 100 200 300 400 500 200 400 600 800 100 150 200 250 300 350 400 50 -300 -2 0 0 -4 0 0 0 0 2 -1.5 0.5 -3 3 -250 -1 1 vtxZ -2 4 -0.5 1.5 -200 target: dimuon mass target: dimuon phi target: dimuon pT -1 target: dimuon z0 5 0 2 target: flag p1 p1 p0 p0 c c / ndf 2 RMS RMS Mean Mean Entries Entries 2 / ndf -150 0.5 2.5 0 6 1 3 ht_3 ht_3 1 7 0.1707 0.1707 -100 1.5 3.5 383.9 383.9 410.6 / 30 410.6 / 30 0.0127 0.0127 0.1998 0.1998 2 1.735 1.735 12658 12658 8 3.5 3.5 2 4 -50 RMS RMS Mean Mean Entries 12658 Entries 12658 RMS 0.4846 RMS 0.4846 Mean 0.83 Mean 0.83 Entries 12658 Entries 12658 RMS 0.6866 RMS 0.6866 Mean 4.887 Mean 4.887 Entries 12658 Entries 12658 RMS 39.36 RMS 39.36 Mean -159.7 Mean -159.7 Entries 12658 Entries 12658 3 9 2.5 4.5 ht_5 ht_5 ht_4 ht_4 ht_2 ht_2 ht_1 ht_1 4 < m <7 10 3 5 4 0 0 0 1 1 10000 15000 20000 25000 30000 35000 10000 12000 14000 16000 10000 15000 20000 25000 30000 35000 40000 10000 12000 14000 16000 18000 5000 2000 4000 6000 8000 5000 2000 4000 6000 8000 100 150 200 250 300 350 400 50 -2 0 0 -4 0 0 -100 0 0 2 10 3 -1.5 0.5 -3 3 -50 -1 1 -2 4 -0.5 1.5 0 dump: dimuon mass p1 p1 p0 p0 c / ndf c 2 RMS RMS Mean Mean Entries Entries 2 / ndf dump: dimuon phi dump: dimuon pT -1 dump: dimuon z0 5 0 2 dump: flag phi 0.5 2.5 50 0 6 1.15e+04 1.15e+04 hd_3 hd_3 0.1727 0.1727 1.728e+04 / 30 1.728e+04 / 30 1 3 1 7 1.90e+01 1.90e+01 100 0.0023 384068 384068 0.0023 0.2797 0.2797 1.723 1.723 1.5 3.5 2 8 2 4 150 RMS RMS Mean Mean Entries 384068 Entries 384068 RMS RMS Mean Mean Entries 384068 Entries 384068 RMS RMS Mean Mean Entries 384068 Entries 384068 RMS RMS Mean Mean Entries 384068 Entries 384068 3 9 2.5 4.5 hd_5 hd_5 hd_4 hd_4 hd_2 hd_2 hd_1 hd_1 200 0.4836 0.4836 0.8542 0.8542 10 0.6663 0.6663 3 5 4 4.813 4.813 28.08 28.08 42.59 42.59 0 0 2 2 10000 12000 14000 16000 pT 2000 4000 6000 8000 0.5 1.5 2.5 3.5 100 150 200 250 300 350 50 -100 -4 0 1 2 3 4 0 0 1 2 3 4 5 0 1 2 3 4 5 6 0 0 2 0 10 3 -80 0.5 1 -3 3 -60 1 2 -2 4 100x target/dump: dimuon mass 100x target/dump: dimuon pT 100x target/dump: dimuon phi -40 1.5 p1 p1 p0 p0 c / ndf c 2 RMS RMS Mean Mean Entries Entries 2 3 / ndf dimuon: z1_vtx - z2_vtx -1 5 -20 2 4 targetPos hr_3 hr_3 0.01475 0.01475 2.5 0 0 6 5 3.272 3.272 p1 p1 p0 p0 c / ndf c 2 RMS RMS Mean Mean Entries Entries 2 74.59 / 30 74.59 / 30 / ndf 0.01300 20 target 3 0.01300 6 -0.0785 -0.0785 0.030 1.853 1.853 1 11516 11516 7 0.030 p1 p1 p0 p0 c / ndf c RMS RMS Mean Mean Entries Entries dump 2 2 3.5 / ndf 40 7 hr_2 hr_2 2 8 0.5399 0.5399 0.6819 0.6819 60 4 8 hr_4 hr_4 53.02 / 28 53.02 / 28 RMS RMS Mean Mean Entries 396726 Entries 396726 RMS RMS Mean Mean Entries 736262 Entries 736262 3 9 0.0462 0.2211 4.5 -0.3553 -0.3553 0.0462 0.2211 0.8362 0.8362 80 9 5.57 5.57 5002 5002 4/12/2025 Ming Liu 10 3.587 3.587 h4 h4 h2 h2 45.68 / 28 45.68 / 28 0.0613 100 10 10 42.92 42.92 -2.617 -2.617 5 0.0613 0.062 0.8814 0.8814 4 2.127 2.127 2.835 2.835 1.478 1.478 0.062 1459 1459

J/Psi MC at Production: Phi 1000 2000 3000 4000 5000 0 -3 -2 atan2(py0,px0) -1 0 1 2 atan2(py0,px0) RMS RMS Mean -0.002368 Mean -0.002368 Entries Entries 3 htemp htemp 448231 448231 1.814 1.814 4/12/2025 Ming Liu 11

Drell-Yan MC: H and Dump symmetric distributions 10000 20000 30000 40000 50000 60000 1000 1500 2000 2500 3000 3500 4000 4500 1000 1200 1400 1600 1800 2000 2200 1000 1500 2000 2500 1000 1200 1400 1600 1800 2000 2200 2400 500 200 400 600 800 500 200 400 600 800 -300 0 0 0 2 0 0 -2 -4 0 -1.5 0.5 -3 3 -250 -1 1 -2 4 -0.5 1.5 p1 p1 p0 p0 c / ndf c 2 RMS RMS Mean Mean Entries Entries 2 -200 / ndf target: dimuon mass -1 5 target: dimuon phi target: dimuon pT target: dimuon z0 0 2 target: flag -150 ht_3 ht_3 0.5 2.5 0 6 0.0847 0.0847 1796 1796 1 3 975.7 / 30 975.7 / 30 -0.005068 -0.005068 1 0.0056 7 0.0056 1.782 1.782 58365 58365 -100 7.5 7.5 1.5 3.5 2 8 2 4 -50 RMS RMS Mean Mean Entries Entries RMS RMS Mean Mean Entries Entries RMS RMS Mean Mean Entries Entries RMS RMS Mean Mean Entries Entries 3 9 2.5 4.5 ht_5 ht_5 ht_4 ht_4 ht_2 ht_2 ht_1 ht_1 10 3 5 4 0 0.5592 0.5592 0.7981 0.7981 58365 58365 1.018 1.018 58365 58365 5.685 5.685 58365 58365 30.56 30.56 -132.8 -132.8 58365 58365 0 0 1 1 10000 20000 30000 40000 50000 60000 70000 80000 90000 1000 2000 3000 4000 5000 6000 7000 1000 1500 2000 2500 3000 3500 1000 1500 2000 2500 3000 3500 4000 1000 2000 3000 4000 5000 500 500 -100 0 0 0 2 0 0 -2 -4 0 -1.5 0.5 -3 3 -50 -1 1 -2 4 -0.5 1.5 p1 p1 p0 p0 c / ndf c 2 RMS RMS Mean Mean Entries Entries 0 2 / ndf dump: dimuon mass -1 5 dump: dimuon phi dump: dimuon pT dump: dimuon z0 0 2 dump: flag 0.5 2.5 50 0 6 hd_3 hd_3 0.08809 0.08809 1 3 2929 2929 1 1640 / 30 1640 / 30 -0.008588 -0.008588 7 0.00438 0.00438 100 1.779 1.779 95223 95223 1.5 3.5 9.6 9.6 2 8 2 4 150 RMS RMS Mean Mean Entries Entries RMS RMS Mean Mean Entries Entries RMS RMS Mean Mean Entries Entries RMS RMS Mean Mean Entries Entries 3 9 2.5 4.5 hd_5 hd_5 hd_4 hd_4 hd_2 hd_2 hd_1 hd_1 200 10 3 5 4 0.5605 0.5605 0.7986 0.7986 95223 95223 1.026 1.026 95223 95223 5.686 5.686 95223 95223 24.44 24.44 46.28 46.28 95223 95223 0 0 2 2 1000 2000 3000 4000 5000 6000 7000 100 120 140 160 180 10 20 30 40 50 60 70 10 20 30 40 50 60 70 20 40 60 80 10 20 30 40 50 60 70 -100 0 2 0 0 -4 0 0 0 10 3 -80 0.5 1 -3 3 -60 1 2 -2 4 p1 p1 p0 p0 c / ndf c 2 RMS RMS Mean Mean Entries Entries 2 / ndf 100x target/dump: dimuon mass -40 p1 p1 c p0 c p0 RMS RMS Mean Mean Entries Entries p1 p1 p0 p0 c c / ndf 2 RMS RMS Mean Mean Entries Entries 1.5 2 2 2 100x target/dump: dimuon phi 3 100x target/dump: dimuon pT / ndf / ndf / ndf dimuon: z1_vtx - z2_vtx -1 5 -20 2 4 targetPos hr_2 hr_2 -0.03642 -0.03642 -0.004938 -0.004938 hr_4 hr_4 hr_3 hr_3 2.5 0 6 5 0 61.43 61.43 -1.656 -1.656 31.71 / 28 31.71 / 28 62.93 62.93 61.22 61.22 0.40272 0.40272 0.007697 32.82 / 30 32.82 / 30 20 24.9 / 28 24.9 / 28 0.007697 0.004315 0.004315 0.866 0.866 5.497 5.497 33009 33009 3 2.31 6 2.31 0.571 0.8657 0.8657 7 1.487 1.487 10355 10355 1 35378 35378 0.67 0.32 0.571 1.85 1.85 0.67 0.32 40 3.5 7 8 2 60 4 8 RMS RMS Mean Mean Entries Entries RMS RMS Mean Mean Entries Entries 9 3 Ming Liu 80 4.5 9 4/12/2025 h2 h2 12 h4 h4 100 10 10 -0.1183 -0.1183 153588 153588 181439 181439 5 4 41.94 41.94 0 0 1 1

Future Work for improvements Detailed MC simulation with the new polarized target position Prove the systematic error can be controlled to O(0.1%) Target/Dump DY acceptance correction study 100x more MC events to reach O(0.1%) level precision Run2 and Run3 data analysis to understand and correct the large asymmetry Beam axis, directions Detector response to instant beam fluctuations Systematic reduction of the false asymmetry New beam position/direction monitoring instruments? Summer shutdown work 2015? Beam on target luminosity telescope Summer shutdown work 2015? 4/12/2025 Ming Liu 13

4/12/2025 Ming Liu 14

Mings T&E on Pol. DY LDRD T&E @20% level (for budget purpose) Joint effort of (Kun + Ming) Focused efforts Integration and transition from E906 to E1039 Simulations and optimization Polarized target related work Progress 2015 summer shutdown work plan New relative luminosity telescopes etc. Possible electrical and mechanical work in target area Identify and develop experimental approach to do high precision spin asymmetry measurements Simulations with optimal target positions Using E906 data and MC to test and confirm new approaches Future work Target test and installation Pump and cryo NMR Calibration Design and build the target actuator Development of the target control and monitoring software Trigger/DAQ optimization 4/12/2025 Ming Liu 15

Xiaodongs talk at LDRD meeting 3/12/2015 The Measured Asymmetry: PT=0.8 target polarization ~0.1 for pure NH3 dilution factor: In reality, need count all unpolarized material in beam s path, f=0.12~0.14. In JLab Hall B, deep-inelastic scattering data, f=0.14 (eg1-dvcs). Need to control systematic uncertainty on measured asymmetry to (A)meas 0.1% Extremely Challenging !!! 4/12/2025 Ming Liu 16

Xiaodongs talk @LDRD meeting Over two years of data collection, need to carefully monitor the changes of: Beam pulse intensity, duty factor, charge profile, halo Target contents, Helium level, polarization Trigger Eff. detector responses, DAQ dead time Background. Track reconstruction Eff. Control raw false asymmetry: 4/12/2025 Ming Liu 17

Note from Andi and Pat Dilution factor Packing fraction Empty target (what is it) Study of background with distributed vs single target in E906 Study e906 empty vs hole target (david task) background contributions relative luminosity beam monitoring (90 degree monitor) luminosity measurement (measure intensity * target mass) synchronize beam spill with NMR measurements (random or regular) help us determine depol during spill beam asymmetry on target determined by spectrometer: However: assumes symmetric response. Need to measure this. E906 data analyzed. (david kleinjan) beam profile during spill time sync between DAQ and pol target (fast control vs Slow control) What do we need to record on spill by spill from target system. Design Labview for target system. Design interface between labview and DAQ; responsible for recording history influence of changing beam profile; as an example go from symmetric profile to asymmetric. What would be the limits we could see. Also matters for non homogeneous polarization. Rate dependence in spectrometer efficiency as a function of geometry. Does not cancel in 2nd order polarization and intensity connected. Over time pol decreases so need to find a way to have same intensity * p product. beam angle: 4/12/2025 Ming Liu 18