1. Collider Physics and QCD Phenomenology Mike Seymour (based at CERN) HERWIG Monte Carlo event generator –Current version ~ frozen (bug fixes and minor new features only) –HERWIG++ completely new framework (integrated with PYTHIA7) completely new parton shower algorithms (initial-state and final-state) revised hadronization model available now for e + e – annihilation and “real soon now” for hadron–hadron NLO calculations and NLO MCs –Higgs + 2 jets at NLO Collider phenomenology –W/Z production and mass measurement ! Emily Nurse –jet algorithms and top mass measurement ! Chris Tevlin –underlying event effects at Tevatron and LHC Resummation of large logarithms –‘gaps between jets’ ! Albrecht Kyrieleis and JRF matching with BFKL a new source of ‘non-global’ logarithms?

2. Hadron Emission Reactions With Interfering Gluons Physics overview –Angular ordered parton showers –Cluster hadronization model

3. HERWIG – Hadron Emission Reactions With Interfering Gluons Physics overview –Angular ordered parton showers –Cluster hadronization model –Soft underlying event Current development –Parton shower/matrix element matching Hardest emission Multijet matching MC@NLO –Multiple scattering model Jimmy –HERWIG++

4. HERWIG++ –Class structure –New parton shower algorithm –Improved cluster fragmentation model –New underlying event model “Jimmy+Ivan” –e+e– version available now –Basic hadronic processes (Drell–Yan, QCD 2!2) “this year” –Full HERWIG functionality “next year” –Work on Fortran HERWIG rapidly ramping down

6. HERWIG-related phenomenology Underlying events: HERA ! Tevatron ! LHC ? –Four new models! W/Z pt distributions and the W mass measurement –Emily Nurse (DØ student)

7. Tuning HERWIG on W/Z pt distributions E.Nurse, MHS PTRMSQCDLAMVQCUT DEFAULT0.00.180.48 HERWIG TUNE 1.60.140.19 MC@NLO TUNE 1.350.190.50

8. NLO Jet Calculations S.Catani, MHS: Nucl.Phys.B485(1997)291; SC, S.Dittmaier, MHS & Z.Trocsanyi NPB627(2002)189 –Subtraction method, based on –Universal (dipole) factorization theorem Implemented in –EVENT2, DISENT, ORIENT (MHS) –NLOJET++ (Zoltan Nagy) –MCFM (John Campbell and Keith Ellis) Single framework for NLO implementations of all ‘femtobarn’ processes at Tevatron Ideal starting point for universal implementation of MC@NLO?

9. Jet Algorithms Cone vs cluster algorithm MHS, Z.Phys.C62(1994)127 Top mass reconstruction as a test case Update in progress (Chris Tevlin, ATLAS student) Cluster Cone

10. Resummation of Large Logarithms Event shape cross sections »  s n log 2n Non-global event shapes and non-global logs (Dasgupta and Salam, Phys.Lett.B512(2001)323; JHEP0203(2002)017) Interjet observables, rapidity gaps (R.B.Appleby and MHS, JHEP0309(2003)056) Work in progress –More non-global contributions? –Resummation of non-global logs? –Application to exclusive diffractive Higgs production…