SM Benchmarks/PDF Uncertainties Webpage

This webpage was started at Les Houches 2005 in order to establish/summarize some of the Standard Model

benchmarks needed for the LHC. It will be continued with Les Houches 2007 which will take place June 4-22.

The writeup for the Les Houches SM/Higgs working group can be found here.

The review article "Hard Interactions of Quarks and Gluons: a Primer for LHC Physics", written with John Campbell and

James Stirling can be found here.

The current (Dec 2006) version of the jet subroutine can be found here. If you use it, please send an email to huston@msu.edu so we can keep you updated.

SM benchmarks for the first year(s) of the LHC

- expected cross sections for useful processes
- inclusive jet
production

- simulated jet events at the LHC
- jet production at
the Tevatron

- a link to a CDF thesis on inclusive jet production in Run 2
- CDF results
from Run II using the kT algorithm

- photon/diphoton
- Drell-Yan cross sections

- W/Z/Drell Yan rapidity distributions
- W/Z as luminosity benchmarks
- impact of LHC W measurements on pdf uncertainties (from Mandy Cooper-Sarkar)
- pdf version available here

- W/Z+jets,
especially the Zeppenfeld
plots (see discover_sm talk below)

- top pairs
- ongoing
work, list of topics (pdf file)

- what are the uncertainties? what are the limitations
of the

theoretical predictions?

- indicate scale dependence of cross sections as well as pdf uncertainties
- to what extent are the predictions validated by current data?
- what measurements could be made at the Tevatron and
HERA

before then to add further information?

- technical benchmarks
- jet algorithm comparisons
- midpoint vs simple iterative cone vs kT
- top studies at the LHC
- an interesting data event at the Tevatron that
examines different algorithms

- Building Better Cone Jet Algorithms
- one of the key aspects for a jet
algorithm is how well it can match to perturbative calculations; here
is a 2-D plot for example that shows some
results for the midpoint algorithm and the CDF Run 1 algorithm (JetClu)

- here is a link to Fortran/C++ versions
of the CDF jet code

- fits to underlying event for 200 540, 630, 1800, 1960 GeV data
- interplay with
ISR in Pythia 6.3

- establish lower/upper variations
- extrapolate to LHC
- effect on target analyses (central jet veto, lepton/photon isolation, top mass?)
- variation of ISR/FSR a la CDF
(study performed by Un-Ki Yang)

- power showers versus wimpy showers

- number of additional jets expected due to ISR
effects (see also Sudakov form factors)

- impact on top analyses
- effect on benchmarks such as Drell-Yan and diphoton production
- goal is
to produce a range for ISR predictions that can then be compared at the
LHC to Drell-Yan and to diphoton data

- Sudakov form factor compilation
- probability for emission of 10, 20, 30 GeV gluon in initial state for hard scales of 100, 200, 500, 1000, 5000 GeV for quark and gluon initial legs
- see for example, similar plots for quarks and gluons for the Tevatron from Stefan Gieseke
- predictions for W/Z pT and rapidity at the LHC
- compare ResBos(-A), joint-resummation and Berger-Qiu for W and Z pT distributions
- impact of final state QED corrections
- predictions for Higgs pT and rapidity at the LHC
- comparisons of parton shower Monte Carlo, fixed order, MC@NLO, and resummation calculations
- see
Peter's precision SM shapes talk below

- now/after HERAII + Tevatron Run II/after 1 year of LHC running
- differences between CTEQ and MRST predictions/uncertainties
- reliability of NLO QCD/progress towards NNLO

- here is a list of priortrized higher order calculations to be finished before or soon after the LHC turn-on
- Stefan Dittmaier
has solemnly promised to calculate at these one of these before the LHC
turns on

- is it possible to guesstimate the size of uncalculated higher order corrections based on past experience for related processes
- for example, gg initial states tend to produce large higher order corrections
- tT at the Tevatron
- gamma gamma at the Tevatron
- can any similar generalizations be performed at the
LHC

Many of these issues are also in common with the TeV4LHC

workshop. See www.pa.msu.edu/~huston/tev4lhc/wg.htm .

First meeting Tuesday May 4 14:00-18:00 Auditorium

Discovering the SM at the LHC J. Huston

a more complete version presented at Aspen is shown here

Higgs production at the LHC M. Grazzini

Bottom fragmentation in Higgs and top decays G. Corcella

Second meeting Saturday May 14

Sudakov resummation effects for parton distributions L. Magnea

Weak corrections to hadronic observables S. Moretti

Dedicated and generic searches at the LHC M. Krasny

Generic Analysis and Optimal Observables L. Dudko

Precision SM shapes P. Skands

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