HzTool, JetWeb and CEDAR

Tools for validating and tuning MC models

Ben Waugh, UCL

Workshop on “HERA and the LHC”

Working group 5: MC Tools

CERN, 2004-03-27

HzTool, JetWeb, CEDAR

Physics goals

Available tools: status and plans

HzTool

JetWeb

HEPDATA

The next step: CEDAR

References

Physics goals

Test, validate, tune and compare MC models (inc. NLO)

Make best use of existing data

tuning to one data set can spoil agreement with others

different measurements may be sensitive to same effects

want to use many different distributions simultaneously

Non-trivial task since measurements

from variety of colliding beams

different regions of phase space

many complex observables

HzTool

Product of HERA “Future Physics” workshop, with contributions from many authors

Reproduce experimental distributions

Produce comparable plots from MC events

Library of Fortran routines

typically one per paper

generally written by paper authors

Use event data from HEPEVT common block

(almost) independent of generator used

HzTool: status

Many new analysis routines since first release

HERA, Tevatron, LEP, SPS

Were two (known) active versions: JetWeb and Hannes Jung

Now merged in JetWeb repository

Interfaces to Cascade and RapGap as well as Pythia and Herwig

Some extra analysis routines

Soon working with Herwig 6.505 (with Jimmy)

JetWeb

Developed at UCL

Database of data and MC plots

Fits (varying normalization) between different MC models and selected data

Web interface:

find fits using required model

submit request for MC if model not in database

Currently limited to a few MC generators and PDFs

Need to extend this to make it more useful

JetWeb: behind the scenes

Java object model:

data: papers, plots, data points

MC: models, logfiles etc.

fits

Java servlets running in Tomcat servlet container within Apache web server

Data stored in MySQL relational database

Plots produced using JAS (Java Analysis Studio)

Data input via XML (using subset of JAS plotML)

Writes job scripts to run MC on batch farm or grid

JetWeb: components

JetWeb home page

JetWeb search form

JetWeb search form (2)

JetWeb search results

JetWeb fit

JetWeb plots

JetWeb compare fits

JetWeb: status and ongoing work

Database frozen: can search but not submit jobs

Existing framework not flexible enough

Need to “factor out” generator-specific details

Need to combine different runs into appropriate models

minimum bias, high-pt jets, beauty production

some parameters vary between run types

e.g. ptmin must be large for jets, 0 for min bias

Use list of “irrelevant parameters” for each run type

already used for ee, ep, pp runs

extend to different run types

must be done for each generator

HEPDATA

Durham HEP Databases

reaction data

parton distribution functions

also literature, names, experiments...

Very comprehensive!

Reaction data provided as “flat” text files

Good for humans, but not for automated tools

A relational database (RDB) would be better

CEDAR

Combined E-science Data Analysis Resource

Collaboration between UCL (JetWeb) and Durham (HEPDATA)

UCL: J M Butterworth, S Butterworth, B M Waugh

Durham: W J Stirling, M R Whalley, A N Other

Funded from PPARC e-Science budget 2004–08

first full release in time for LHC start-up

Three areas:

Reaction data: start with HEPDATA

Model validation: start with JetWeb

Code repository

CEDAR: Reaction data

Migrate HEPDATA to a relational database (work started)

Enable direct input of data by collaborations using Grid authentication tools

Define standard XML format for data exchange

Access via Web and Grid tools

CEDAR: Model validation

Make JetWeb more modular, using object-oriented design principles

Extend to more models (currently still two Herwig versions + one Pythia)

Access HEPDATA directly rather than maintaining separate database

Replace HzTool with OO framework

CEDAR: Code repository

Model validation requires well defined versioning of generators, PDF fitting codes, jet algorithms...

Propose to establish repository with Web and Grid access

Can obtain JetWeb-validated version here

Could be used as official version by authors

References

HzTool

http://www.desy.de/~carli/hztool.html

http://jetweb.hep.ucl.ac.uk/Doc/cvs.html

J Bromley et al., Future Physics at HERA, vol 1, pp 611-612

JetWeb

http://jetweb.hep.ucl.ac.uk/

J M Butterworth & S Butterworth, Comp. Phys. Commun. 152 (2003) 164-178

HEPDATA

http://www-spires.dur.ac.uk/hepdata/

CEDAR

nothing yet!

Ben Waugh

2004-03-21T22:28:35