Priority Data Set for MC Validation
Lots of data exist. Some of them are more important than others for MC validation and tuning for the LHC, which is our current priority task. This page contains current thoughts on priorities, compiled in discussion with experiment and generator authors and various meeting and by email.
The numbers in (brackets) are the current priority as assigned by the JetWeb team on that basis. This does not necessarily mean "how important are these items" but also reflects the fact that we are well supplied with some data types (mainly HERA) and less well with others. We will work ourselves on the data in priority order, but all offers of help are gratefully received. If you want to edit this page and don't know how, please mail jetweb @ cedar.ac.uk
A more complete list of routines missing from HZTool is being compiled here. A similar list for Rivet should appear when rivet works. These don't reflect such specific priorities - there are other reasons for wanting data in there than "just" LHC validation.
LEP Data
- Z-> hadrons: charged particle multiplicity, event shapes, jet rates. Validation of matrix elements; final state parton showers; hadronisation (1).
- Charm and beauty rates would also be useful for validating heavy flavour production. However, much of the particle composition can be taken from experiment-averaged tables in PDG, and therefore is not urgently needed in JetWeb. (4)
- Light and heavy particle composition, x distributions, correlations, for checking fragemation, baryon production, secondary heavy flavour production (3)
- Gamma-gamma data. May be useful for checking jet and underlying event models, but primarily useful for photon physics, so of more interest to ILC than LHC and therfore lower priority at present. See the tasks and people associated with this JetWeb milestone.
What's in JetWeb at present
Nothing yet from 45 GeV e- 45 GeV e+ collisions - needed urgently.
HERA Data
Assume all parton densities used are validated by the fitting group with the latest HERA data. Next most important data sets might be;
- DIS event shapes for initial state parton shower and matrix element, as well as proton remnant. This should be the best and simplest way of testing/tuning these aspects of models. Problems are that ep processes may not be implemented in new generators in time. Also PYTHIA has a particular problem in that the parton shower used in DIS is not the same as that used in pp(bar). (3)
- Heavy flavour in DIS and photoproduction for QCD heavy flavour production. (3)
- Jet shapes and jet rates in DIS and photoproduction for validating initial and final state radiation. (3)
- Particle and energy flows, multijets and rapidity gaps for underlying event, diffraction and absorption corrections. Underying event models in PYTHIA cannot be tuned using this, since only the simple model is implemented for photoproduction. (4)
What's in JetWeb at present
Tevatron Data
- Minimum bias and underlying event data, including long range f/b correlations and pT spectra (1)
- gamma*/Z drell-yan pT spectra for checking initial state radiation. (1)
- Inclusive and multi-jet rates (2)
- Jet shapes and subjet multiplicities (2)
- Heavy flavour production (3)
- Exclusive dijets for diffraction and absorption corrections. (4)
What's in JetWeb at present
Others
- Min bias data from SPS experiments and RHIC pp. Needed to study energy dependence of minbias and underlying event. Min bias cannot be used to tune JIMMY since JIMMY has a hard PTMIN cut-off. (2)
- e+e- jets and event shapes from PETRA. Similar motivation to the LEP hadronic data, but lower energy so less parton showering. (2)
Links and Resources
- CMS note on tuning (from Paulo Bartalini)
- MC4LHC slides from Torbjorn Sjostrand.
