2016 pPb run preparation by Rice heavy ion group

Physics cases (what are the big questions? what physics measurements? what triggers? how many events?)

• High Multiplicity (8TeV 100nb-1 projection: pPb_mult_scale_8p16TeV.pdf, pPb_mult_scale_8p16TeV_ratio_to_5p02TeV.pdf)
  

• Can we establish connection between v_n and initial spatial eccentricity in pp and pPb?
  • v3{4}/v3{2} = v2{4}/v2{2} ? (hydro prediction) Can we measure v3{4}?
  • v2{8}/v2{6}, v2{6}/v2{4} vs v2{4}/v2{2} follow hydro curve?
  • pT and eta dependent factorization breaking and PCA: can we use 4-p cumulant to do it in pp?; p_T1 vs p_T2 correlation
  • Does v2{2} decrease at very high Noff?
    • v2,3{2} can reach N=(380,410) with same precision as the last bin in HIN-13-002 with N=(320,350)
    • v2,3{2} vs pT measurable at N=(260,300) with same precision as N=(220,260) in HIN-13-002
  • Event shape engineering: to what extent can we do this? v2 vs v3 correlations and SC correlator

• Can we observe evidence of jet quenching?
  • How to measure high pT (~ 10 GeV/c) v2? Have to do at least 4-particle ...
    • Can we implement a gap?
    • Assuming nonflow is independent of v2{2}, measure v2{2} vs c2{4} using event engineering and fit with v2{2} = a * (-v2{4})^4+C. Need to trigger on HM+Q2

• Does collectivity persist down to very low multiplicities? If so, what is it?
  • What is the transition from low to high N_trk for collectivity?
    • multi-particle correlation with eta gap
      • at low N, might need large amount of MB events?
  • v2 in pp with different leading pT cut
  • v2{2} with even larger eta gap

• What is the origin of quark number scaling?
  • v2(Ks, Lambda) vs v2(hadron)

• Does heavy flavor quarks flow in small systems?
  • D (and phi) meson v2 (dE/dx to reach low pT)
  • v2(D, phi, Ks, Lambda) vs v2(charged hadron)
  • Lambda_c -> Lambda + pion; Lambda_c -> Ks + proton; D0 -> Ks + pion(zero? or Kspipi) reconstruction
  • D v2 from 4-particle cumulant

• Ridge in photon-nucleus collisions

• Evidence of saturation: rapidity dependence of dihadron correlations

Priority analysis (TBD)

• D meson v2 (Zhenyu, Aobo)
• v3{m} and v2{m} vs N_trk (Maxime)
• v2 vs v3 correlation, SC(m,n) correlator (Maxime)
• Baryon number separation or CVE (Kong)
• CMW (Sang Eon)
• V0/Xi v_n (Ben)
• Lambda_c or UPC ridge or eta dependence of dihadron correlations (Johann)
• 2p-corr (Wei)
• Lambda polarization (Wei)

Data format:

• V0 related analyses: skim of new V0 collection + parent file (?)
• D0 related analyses:
  • skim of new D0 collection + parent file (?)
  • forest without tracks using HF SP method (?)
  • forest with track Q vectors in eta slices (?)
• azimuthal correlation related:
  • two-particle correlations on AOD/skims
  • Maxime's Q vector trees for all cumulants

Trigger ideas

• HM (v3{m}, v2{m}, factorization)
• HM+D meson (D v2)
• HM+V0 (CME with baryon separation, Lambda polarization)
• HM+high pT track, HM+Q2 (v2{2} vs c2{4})

Brain Storming

• Wei
• Zhenyu
• Kong
• Maxime
• Aobo
• Sang Eon
• Benjamin Tran
• Johann Gan
• New PD

Triggers