1. AliRoot survey: Generators
P.Hristov
11/06/2013

2. Are you involved in activities related to particle generation. (37
Are you involved in activities related to particle generation? (37.4% Yes, 62.6% No)

3. Particle generators in use

4. Requests for additional generators
New NLO generators
New interface development wrt PYTHIA & HERWIG already on- going
Pythia 8 may become our default pp MC generator (maintained and developped version of Pythia)
EPOS could become an interesting option (description of pp, pPb, PbPb with one model), though I am not sure the code is public...
JEWEL once it is available in public
UrQMD
STARLIGHT for generating ultra-peripheral interactions
In other experiments I saw events could be read out from ascii files produced by event generators. A standard event format like OSCAR can be used for such input. In this case there will be no limitations in generators used in aliroot.
CORSIKA: to perform cosmic ray studies in Alice

5. Code of generators as part of AliRoot

6. Code of generators as part of AliRoot
Advantages
Disadvantages
Code version/settings are known
No need for revision management. Assured to get "correct" version.
Works great/easy to use/easy access, install & process
Better integration into the AliRoot software, very important for stability
The virtual MC allows simulations regardless the input generators
No need to compile yourself, self- contained
Immediate availability, no need of external code
Source code is often needed to understand any problems with generators. Availability of the generators in AliRoot ensures that results are reproducible.
Very user friendly
Separate library of generators should make the code more flexible
Too much external code; not always up-to- date.
Physics wise, the simulations are stuck at generator versions that may be not that good, deprecated, etc... while the work of maintenance must be heavy for the offline team (?)
AliRoot installation crashes very often
A potential bug in the interface to AliRoot would be very hard to spot (differences wrt standalone generator)?
Not easy to plug in a new generator.
Greatly increases size of AliRoot, links too closely AliRoot with Generator, makes it difficult to use a different version.