Presentation is loading. Please wait.

Presentation is loading. Please wait.

Introduction to the workshop LHCb Generators Tuning Mini Workshop Bucharest 22 nd & 23 rd November 2012 LHCb Generators Tuning Mini Workshop Bucharest.

Similar presentations


Presentation on theme: "Introduction to the workshop LHCb Generators Tuning Mini Workshop Bucharest 22 nd & 23 rd November 2012 LHCb Generators Tuning Mini Workshop Bucharest."— Presentation transcript:

1 Introduction to the workshop LHCb Generators Tuning Mini Workshop Bucharest 22 nd & 23 rd November 2012 LHCb Generators Tuning Mini Workshop Bucharest 22 nd & 23 rd November 2012 Gloria Corti, CERN

2 Workshops aim Providing a forum for discussion between MC and LHCb on exchange of views and requirements How LHCb uses the MC MC requirements for the LHCb program Tuning to the LHCb data How the LHCb measurements can be used for general tuning Provide information on the latest and planned development in the main MC general purpose generators Pythia8 Sherpa Herwig++ and in EvtGen, the LHCb reference for the decays LHCb Generators Tuning mini workshop - Bucharest - 22 Nov. 2012 Page 2 Introduction, G.Corti

3 Tuning Status of the general purpose generator tuning What data has been used Tuning in the forward region Issues of interest for LHCb Fragmentation bb correlations Heavy flavor production correlations, b&s,b&c Production asymmetries Diffractive events … Rivet and making the published LHCb data available for reference How do the PDF choice influence the tuning LHCb Generators Tuning mini workshop - Bucharest - 22 Nov. 2012 Page 3 Introduction, G.Corti

4 LHCb Designed to search for New Physics through precision measurement of CP violation and Rare Decays of heavy flavors at the LHC Initial aim of LHCb was b-physics but demonstrated it can also do Charm physics (oscillations, CP violation) QCD physics (Ks and Lambda production, PDFs via Z/W production, Central Exclusive Production,...) Trigger and reconstruct many different decay modes to make independent and complementary measurements LHCb Generators Tuning mini workshop - Bucharest - 22 Nov. 2012 Page 4 Introduction, G.Corti

5 Page 5 LHCb LHCb is a single arm forward spectrometer Forward production of bb, correlated LHCb Generators Tuning mini workshop - Bucharest - 22 Nov. 2012 Introduction, G.Corti Covers ~4% of the solid angle, but captures ~40% of the heavy quark production cross-section

6 MC samples in LHCb In LHCb the majority of MC samples are proton-proton collisions with specific decay of b or c hadrons, but not only. Pythia6 has been used so far for the production of the events for the analysis But also Pythia8 for diffractive production We have extensions to Pythia6 for B c and Chi bc, cc production Recently we have been put in place an AlpGen + Pythia production all wrapped in our simulation framework with intermediate LHA temporary files produced Also interest expressed by some analysts for MC@NLO and POWHEG EvtGen is used to model the decay of all particles Default behavior is governed by a general DECAY.DEC table with all known decay modes for all particles User decay files are used to force a specific decay for a signal particle via specific models

7 MC Productions MC productions are very time consuming Detector simulation is slow (~1-2 min/event) The MC productions hare handled centrally and in a transparent way following implemented conventions and procedures Experts concentrate on their task Massive and efficient production on a world-wide distributed system But this puts constrains on how generators can be integrated in the LHCb simulation framework to allow for production in this distributed system MC samples need to be produced with a well defined production configuration with conditions (beam, detector and trigger) and processing (trigger, reconstruction and stripping) consistent with data Cannot introduce new generators versions too often although we want to do it when new interesting features become available it also requires testing and validation LHCb Week - 23 October 2012 Simulation for 2012, G.Corti

8 Page 8 Mjobs Size of Monte Carlo productions ~ 500 events/job Production for analysis of 2011 full data sample and early analysis of 2012 data is ongoing since December 2011 ~ 1.7 billion events produced Different running conditions (beam & trigger) Different reconstruction processing to match the data Wide variety of signal and background samples for different analysis 655 up to last week (~ of 170 in each previous years MC Data Challenges) Samples from 50k to 10M event Some samples are shared between physics analysis Essential to keep samples consistent for a given configuration Ensure samples are available to the whole LHCb collaboration

9 New generation generators In the process of replacing Pythia6 with Pythia8 as default generator In production to start early next year generate 50% of all signal events Can be used to generate minimum bias, inclusive and « normal » B signal events Working version with latest version 170 in Gauss (Aurélien Martens, Alex Grecu): Commissioning for production in final phases  What tune? Interfacing POWHEG BOX to PYTHIA8 (Philip Ilten) Moving to new version of EvtGen With delegations to Pythia8, Photos++ and Tauola++ Integration in Gauss simulation framework of other generators in different stages of work Herwig++ (Philip Ilten) Sherpa (Julian Wishahi) LHCb Week - 23 October 2012 Simulation for 2012, G.Corti

10 Page 10 Timetable LHCb Generators Tuning mini workshop - Bucharest - 22 Nov. 2012 Introduction, G.Corti https://indico.cern.ch/conferenceOtherViews.py?view=standard&confId=214491 Page 10 Thursday 9:30-11:00 How generators are used in LHCb 11:00-13:00 Pythia8 14:30-15:30 EvtGen 15:30-17:30 Sherpa Friday 9:30-11:00 Herwig++ 11:00-13:00 Tuning and Tuning tools 14:00-14:30 Influence of PDFs 14:30-15:30 Tuning needs in and input to tuning by LHCb

11 Page 11 Timetable LHCb Generators Tuning mini workshop - Bucharest - 22 Nov. 2012 Introduction, G.Corti https://indico.cern.ch/conferenceOtherViews.py?view=standard&confId=214491 Page 11 Thursday 9:30-11:00 How generators are used in LHCb 11:00-13:00 Pythia8 14:30-15:30 EvtGen 15:30-17:30 Sherpa Friday 9:30-11:00 Herwig++ 11:00-13:00 Tuning and Tuning tools 14:00-14:30 Influence of PDFs 14:30-15:30 Tuning needs in and input to tuning by LHCb Aim to define how we can work together on some of the issues that will be discussed


Download ppt "Introduction to the workshop LHCb Generators Tuning Mini Workshop Bucharest 22 nd & 23 rd November 2012 LHCb Generators Tuning Mini Workshop Bucharest."

Similar presentations


Ads by Google