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Two issues w/ respect to simulation readiness

Updated on Wed, 2009-12-02 11:38. Originally created by jwebb on 2009-12-02 11:19.

There are two issues being discussed within several groups (emc, phana, W) which may impact our readiness to run simulations for y2009.  The issues are (1) the EEMC sampling fraction is nonlinear at high energy, and (2) the BEMC (and EEMC) sampling fractions exhibit a dependence on pseudorapidity which depends on the geant cuts being utilized.

I asked a few questions (both publicly on simu and behind the scenes) to get a better idea where we are on these issues.

Issue 1 was discussed in the EMC phone this week, and the observed nonlinearities are likely consistent with saturation of the 12-bit ADCs at ET=60 GeV in the fast simulator.  Hal will update his blog entry to show this explicitly.
 
Issue 2 has been discussed on emc2 and simu hypernews forums, in the emc and W phone meetings, and likely a few hallways.  It is an open issue whether to use:
 
(a) the default geant cuts in simulation (cutele=1 MeV, cutgam=80keV), or
(b) lower thresholds via the geometry LOW_EM option.  

No strong evidence has been presented showing that the LOW_EM option improves agreement between data and MC.  

  • Either option requires modification to the slow simulator(s) in the barrel (and likely endcap) to better match the simulated sampling fractions.
  • Once a decision has been reached on geant cuts (Matt Walker thinks a final decision will be made during Monday's EMC phone)
    • BEMC slow simulator code is ready to be checked into CVS.  
    • No timeframe from EEMC group, ... but my impression from following Ilya's studies is that the studies have already been done (or can be done quickly) and the slow simulator updated early next week.  (??)
  • There may be a need for a test sample with LOW_EM option, presumably to help resolve whether the LOW_EM option improves agreement between data and Monte Carlo or not.

 

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