Lectures on Monte Carlo methods for high energy physics

21 Sept 2009, 08:00 → 25 Sept 2009, 18:00 Europe/Rome

Auditorium B. Touschek (INFN - Laboratori Nazionali di Frascati)

In the following lectures Prof. Zbigniew Was will present main ideas of Monte Carlo methods as used in simulations of physics processes for high energy physics experiments.
In the presentation Prof. Was will use QED distributions because there, in principle, everything can be calculated with arbitrary precision and simulation of tau decays, because in this case input from models to be validated by data is essential.

Principles of Monte Carlo method

• Rejection
  
• Importance Sampling
  
• Branches of the Generation
  
• Crude Distribution Overall Normalization and Rejection again
  
• What is Markovian and non-Markovian algorithm
  

Phase space

• Parametrization of Exact n-body Phase Space
  
• Multichannel Generation
  
• Phase Space Semi-Factorization
  

Matrix element, case when it is calculable

• Convergence and Theoretical Errors in case of Experimental Cuts
  
• Soft Photons can be ignored
  
• QED Infrared Singularities and Negative Weights
  
• Useful Properties of Matrix Elements, factorization and exclusive exponentiation
  

Matrix element, case when it must be deduced from data

• Matrix Element for Tau Decay
  
• Hadronic current constraints from Lorentz and (hints?) from chiral and isospin symmetry
  
• Relation to Measurable Distributions
  

Special Monte carlo techniques

• Correlated Samples
  
• Applications to remove unwanted (known) physics such as bremsstrahlung in decays
  
• Event weighted with alternative models for fits
  

Bibliography (incomplete):
1) Notes of my lectures on similar topic http://cern.ch/~wasm/public/zakopane.ps.gz
2) References on TAUOLA and PHOTOS which I will use as source of examples. In particular:
3) ``PHOTOS: A Universal Monte Carlo for QED radiative corrections. Version 2.0'' E. Barberio and Z. Was Comput. Phys. Commun. 79, 291 (1994)
4) ``The Tau Decay Library Tauola: Version 2.4''S. Jadach, Z. Was, R. Decker and J. H. Kuhn Comput. Phys. Commun.76, 361 (1993)
5) ``Scalar QED, NLO and PHOTOS Monte Carlo'' G. Nanava and Z. Was Eur. Phys. J. C51, 569 (2007)
6) ``Library of SM and anomalous W W gamma couplings for the e+ e- --> f anti-f (n)gamma Monte Carlo programs'', A. Jacholkowska, J. Kalinowski and Z. Was Comput. Phys. Commun. 124, 238 (2000)

Monday, 21 September

15:00 → 16:30 Principles of Monte Carlo Method

Rejection

Importance Sampling

Branches of the Generation

Crude Distribution Overall Normalization and Rejection again

What is Markovian and non-Markovian algorithm

16:30 → 17:00 Coffee Break

Tuesday, 22 September

15:00 → 16:30 Phase Space

Parametrization of Exact n-body Phase Space

Multichannel Generation

Phase Space Semi-Factorization

16:30 → 17:00 Coffee Break

Wednesday, 23 September

10:00 → 11:30 Matrix Element, case when it is calculable

Convergence and Theoretical Errors in case of Experimental Cuts

Soft Photons can be ignored

QED Infrared Singularities and Negative Weights

Useful Properties of Matrix Elements, factorization and exclusive exponentiation

11:30 → 12:00 Coffee Break

Thursday, 24 September

10:00 → 11:30 Matrix Element, case when it must be deduced from data

Matrix Element for Tau Decay

Hadronic current constraints from Lorentz and (hints?) from chiral and isospin symmetry

Relation to Measurable Distributions

11:30 → 12:00 Coffee Break

Friday, 25 September

10:00 → 11:30 Special Monte Carlo Techniques

Correlated Samples

Applications to remove unwanted (known) physics such as bremsstrahlung in decays

Event weighted with alternative models for fits

11:30 → 12:00 Coffee Break