Activity log

Activities are grouped by week, starting on the given date.

12/05/2014

• Preparing talk for UCL's institutional review of ATLAS EXOT-2013-19 (draft of paper to be published in journal). Document: http://cds.cern.ch/record/1701155 [ATLAS internal].
• Meeting with Emily. Discussed three possible ATLAS analyses that I could work on:
  1. Higgs production via VBF, measuring differential cross section in four-lepton channel. (Most promising for MC studies.)
  2. Dark matter search using monojet events. New approach to reducing systematic uncertainties. (MC challenges are not expected.)
  3. "X -> H H -> b bbar tau+ tau-" analysis. Katherine and others are already working on this. (MC challenges are expected to be negligible compared to experimental ones.)
• Writing reports (First year review, ATLAS qualification task)
• Signed up for STFC HEP summer school (31.8.–12.9. in Warwick)

10/03/2014

• More studying of Pythia's main31 and ttbar modelling

• Configuring my own stand-alone HEP software (generators, Rivet, and auxiliary software) on LXPlus and writing scripts for generating events and running Rivet
• Following up on the curious behaviours in Pythia's main31

• First interesting findings on functioning of Pythia's main31
• Reading:
  • Buckley et al.: "General-purpose event generators for LHC physics" [arXiv:1101.2599]

• Working on understanding Pythia's main31

• Exams on Monday and Tuesday
• Now I can:
  • Generate ttbar events with Powheg
  • Process Powheg events with Pythia 8 (i.e. using LHE file input) in main31
  • Process LHE files containing NLO process with Pythia without the additional functionality of main31
• Currently learning to:
  • Save Pythia output (as HepMC files or ROOT files?) and process it with Rivet
  • Generate and process events on my own computer with the same settings as I do in Athena on-the-fly (this is the 'ultimate goal')
• Seminar "QCD resummation for jet and hadron production" by Werner Vogelsang (Universität Tübingen)
• Reading:
  • Sjöstrand, Mrenna, Skands: "A Brief Introduction to PYTHIA 8.1" [arXiv:0710.3820]

• Nothing but revising for exams next week many hours a day

• Revising for exams

• Installed a heap of HEP software
• Work on understanding Main31 (the version that ships with Pythia 8)
• Mini-workshop about the future of HepMC
• ATLAS MC generator meeting, discussed coordination of top modelling work with others (Thorsten Kuhl, Dominic Hirschbühl, Liron Barak, James Monk)

• ATLAS UK meeting in Edinburgh, including ATLAS software workshop (Monday to Wednesday)
• Work on understanding Main 31 in detail and writing notes about it (part of which could later enter my thesis as well as ATLAS instructions)
• Got a new laptop (MacBook Pro)

23/12/2013 (on holiday)

16/12/2013

• Prepared talk for UCL HEP group Christmas meeting (First presentation of work to UCL HEP group)
• Leaving on vacation 19/12/2013

• (I was designated an MCnet advisor: Torbjörn Sjöstrand)
• Got Main31 user hook to work with Powheg+Pythia8. Generated 50k events and produced Rivet plots
• Tried to turn off all Pythia parton-level activities except hard process. Pythia complains about these events, after 499 failed events throws exception. Disable Pythia's (and TestHEPMC's) self-checks for running
• Presented first plots and ideas about ATLAS ttbar service task to James Monk, Stefano Camarda and Stephen Bieniek (slides)
• Gave a similar presentation at the UCL weekly ATLAS meeting (slides)
• TTbar TODO (not exhaustive):
  • Use leading-order PDFs for Pythia (recommended, since no negative gluon contributions as in NLO PDFs). Eg. HERAPDF, CTEQ6.1
  • Continue using NLO PDFs for Powheg (CT10 is fine)
  • alphaS is quite high in the Pythia showers. Lowering its value (eg matching to the value in the PDF) might reduce jet activity as desired.

• (Working from Helsinki November 27–29)

• Work on gg -> H calculation:
  • Learned about Veltman-Passarino reduction
  • Here's a slightly updated version of the report. Still ugly and work-in-progress.
• Gerard 't Hooft's lecture at King's College: "Conformal symmetry in black holes and quantum gravity" (Was awesome!)
• Reading
  • Corke, Sjöstrand: "Improved Parton Showers at Large Transverse Momenta" [arXiv:1003.2384v1]
  • Seymour, Marx: "Monte Carlo Event Generators" [arXiv:1304.6677v1]

• Tried this: 2 days lectures, 1 day NLO calculation, 1 day ATLAS service work, 1 day course homework
• Ran Rivet within the ATLAS software (Athena) with help from Stephen B.
• Got organised with service task and Athena: created TODOs, directories, setup scripts, git repositories, etc.
• Produced more samples
• More work with FORM, progress but no perfection so far
• Reading
  • Ellis, Stirling, Webber: "QCD and Collider Physics" (started)

• Started working on ATLAS service task
  • Skype talk with James Monk, Stephen Bieniek, Keith Hamilton
  • Set up Athena and generated some events (ttbar, POWHEG + PYTHIA 6/8)
• Compiled and installed a heap of software on my laptop
  • ROOT 5.34/11
  • GNU Scientific Library (GSL)
  • HepMC, FastJet, yaml-cpp, YODA
  • Working on installing Rivet, not yet successful (make error: library not found for -lSISConePlugin)
• Wednesday and Thursday: Software Carpentry workshop (description, lessons)
• Seminar "H -> bb in ATLAS" by Gabriel Facini (CERN)
• First edit of the (compulsory) PhD student e-log

• Monday and Tuesday: MCnet meeting in Manchester (MCnet meeting slides)
• Writing up some personal notes of general sessions and private conversations at the MCnet meeting (iff they turn out to be good enough, I will upload them here)
• Properly started work on gg -> H @ NLO calculation
• Installed updated versions of GNU autoconf and automake. These will enable easier installation of HEP software.
• Installed and started learning to use FORM, which I need for the NLO calculation

• Prepared a short presentation for the MCnet meeting in Manchester next week (MCnet meeting slides)
• Seminar "FTK: A hardware-based track finder for the ATLAS trigger" by Lauren Tompkins (University of Chicago)
• Reading
  • Bentvelsen, Laenen, Motylinski: "Higgs production through gluon fusion at leading order" [NIKHEF preprint 2005 - 007]
  • Dawson: "Radiative corrections to Higgs boson production" [Nucl. Phys. B359 (1991) 283-300]

• First week with a non-negligible amount of course homework…
• Worked on notes on gg -> H @ LO calculation

• Finished calculation of gg -> H @ LO (notes, work in progress)
• John Ellis' lecture on Higgs physics (2/3) at King's College
• Seminar "Heavy Neutrino Searches at the LHC" by Bhupal Dev (University of Manchester)
• First time at UCL ATLAS group meeting

  <-- Talks:  (Eric Jansen),  (Stephen Bienik). ??? presented herself and her previous work (some interesting points about 3-prong tau lepton "recovery" when only two tracks are detected/resolved) -->

• Lectures started (Monday and Tuesday)
• Continued calculation of gg -> H @ LO
• Got a desk PC and a UCL HEP computing account
• John Ellis' lecture on Higgs physics (1/3) at King's College
• Registered for MCnet meeting in Manchester & booked trains

• Started calculation of gg -> H cross section at leading order
• Read PhD student post-1st-year reports and sent feedback
• Post-1st-year PhD student talks
• HEP group annual meeting
• Registered at UCL
• Start of PhD!

• Feasibility-of-VBF-Higgs-study-2.pdf: Feasibility-of-VBF-Higgs-study-2.pdf

• Feasibility_of_VBF_Higgs_study.pdf: Feasibility_of_VBF_Higgs_study.pdf

• Feasibility-of-VBF-Higgs-study-3.pdf: Feasibility-of-VBF-Higgs-study-3.pdf

• More studying of Pythia's main31 and ttbar modelling

• (Working from Helsinki November 27–29)

• Work on gg -> H calculation:

• Seminar "H -> bb in ATLAS" by Gabriel Facini (CERN)

• Properly started work on gg -> H @ NLO calculation

• First week with a non-negligible amount of course homework…
• Worked on notes on gg -> H @ LO calculation

• Finished calculation of gg -> H @ LO (notes, work in progress)

• Continued calculation of gg -> H @ LO

• Started calculation of gg -> H cross section at leading order

stefan.richter@cern.ch

+358 50 4952406

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