China 2006

Homepage of Volker Friese

Presentations

Proposal for flow of arguments

• Introduction
  • Fluctuations as signature for critical phenomena
  • FAIR/SPS energy regime promising
  • Measurement of K/pi and p/pi fluctuations by NA49
  • Need to check hadronic origin of fluctuations before stating new physics
• UrQMD results (sum kaons/sum pions, sum protons/sum pions)
  • Results in 4pi and midrapidity. Not much difference; energy dependence small.
  • Positive for kaons, negative for protons. Probable source: resonance decays.
  • Check: Results for K+/pi+, K-/pi+ and so on. All negative. Proofs resonance influence (Kstar).
  • Results with Kstar set stable. Correlations diminuish.
• Influence of acceptance
  • UrQmd results with acceptance cuts (rapidity, momentum, azimuth). Discuss influence on fluctuations.
  • Compare with NA49 after proper cuts.
• sum kaons/sum pions is positive -> antocorrelation. Explanation: phi decay.
  • Toy model including strong decay channels
  • Toy model including also weak decay of phi->K0sK0l ->pi+pi-K0l.
  • Discuss probability for pions from V0 to be accepted as primary in the experiment. Possible energy dependence (boost of K0s)
• Predictions for CBM (10 - 35 AGeV) with realistic detector acceptance
• Conclusions
  • ???

Required data / plots

• UrQMD (K+=K-)/(pi+=pi-) and (p+ap/pi+=pi-), 4pi and midrapidity (delta y small) -> Stephane
• same with proper cuts for NA49 acceptance -> Stephane
• UrQMD K+/pi+, K-/pi+, K+/pi-, K-/pi-, 4 pi and midrapidity -> Stephane
• UrQMD without phi, Kstar and both -> Dima

Information requested

• Kinematic cuts applied in the NA49 data analysis (C. Roland)

First paper draft, September 2, 2006

Homepage of Volker Friese

Dielectron Working Group

Meeting 21. September 2006, EuropCafe Strasbourg

• Tracking
  • Improve tracking for low-momentum, short tracks (track segments). This most probably requires a second, dedicated tracking algorithm, maybe running after the main track finder in the chain. The various tracking groups (Heidelberg, LIT, LHE) have to be contacted whether they can work on this task.
  • Look for signatures of closeby tracks of RICH-identified electrons. Such signatures are e.g. a nearby hit in the first or second VTS station. Again, tracking experts should be contacted.
  • Tracking in an odd field. The field required for the LM dielectron analysis is probably different from that used in the standard setup (minimal field between target and first VTS station, minimal field in RICH, still keep the field integral of about 1 Tm). Tracking in such a field may be more difficult and require dedicated efforts.
  • Also needed is the extrapolation of tracks through the RICH mirror, which thus should be appropriately implemented in the Kalman filter.

• RICH
  • Study the influence of noise hits in the PMs on ring finding in the inner part
  • Can secondary electrons, with odd incident angles, can be discriminated by their ring shape or quality?
  • Improve the ring-track matching by
    • not only selecting the track closest to the ring centre, but all within a certain range (2 sigma or so),
    • introduce momentum dependent matching cuts.
  • Check for matching of pions with the rings of their delta electrons

• TRD
  • Include the TRD PID (as already applied by Alla) for RICH-identified electrons to discriminate misidentied pions

• TOF
  • Use TOF information for RICH-identified electrons to suppress misidentified pions.