# MadMiner

Particle physics processes are usually modelled with complex Monte-Carlo simulations of the hard process, parton shower, and detector interactions. These simulators typically do not admit a tractable likelihood function: given a (potentially high-dimensional) set of observables, it is usually not possible to calculate the probability of these observables for some model parameters. Particle physicisists usually tackle this problem of “likelihood-free inference” by hand-picking a few “good” observables or summary statistics and filling histograms of them. But this conventional approach discards the information in all other observables and often does not scale well to high-dimensional problems.

In the three publications “Constraining Effective Field Theories With Machine Learning”, “A Guide to Constraining Effective Field Theories With Machine Learning”, and “Mining gold from implicit models to improve likelihood-free inference”, a new approach has been developed. In a nut shell, additional information is extracted from the simulators. This “augmented data” can be used to train neural networks to efficiently approximate arbitrary likelihood ratios. We playfully call this process “mining gold” from the simulator, since this information may be hard to get, but turns out to be very valuable for inference.

### Team

- Kyle Cranmer
- Johann Brehmer
- Irina Espejo

- Felix Kling

### Presentations

- 'Mining gold' from simulators to improve likelihood-free inference (Johann Brehmer, 18 Mar 2019) at Likelihood-free inference workshop
- Keynote: Constraining effective field theories with machine learning (Johann Brehmer, 14 Mar 2019) at International Workshop on Advanced Computing and Analysis Techniques in Physics Research
- Bringing together simulations, physics insight, and machine learning to constrain new physics (Johann Brehmer, 28 Feb 2019) at Dark universe seminar
- Meticulous measurements with matrix elements and machine learning (Johann Brehmer, 14 Jan 2019) at ITS/CHEP joint seminar
- Improving inference with matrix elements and machine learning (Johann Brehmer, 11 Jan 2019) at HK IAS Program on High Energy Physics
- Learning to constrain new physics (Johann Brehmer, 20 Sep 2018) at IPPP seminar
- Learning to constrain new physics (Johann Brehmer, 13 Sep 2018) at Pheno & Vino Seminar
- Learning to constrain new physics (Johann Brehmer, 27 Aug 2018) at Elementary particle seminar
- Machine Learning to Probe a BSM Higgs Sector (Johann Brehmer, 23 Jul 2018) at Higgs Hunting
- Constraining Effective Theories with Machine Learning (Johann Brehmer, 27 Jun 2018) at Theory seminar