Sven Kreiss in front of Freedom Tower.

I am a Data Scientist at Wildcard in New York City. I recently earned a PhD in Particle Physics from New York University (NYU) where I worked with Kyle Cranmer. At the end of 2012, I returned to New York from a year at CERN, Switzerland. Originally, I am from Germany, then studied for my bachelor’s and master’s degree in Mathematical Physics at the University of Edinburgh, Scotland, and then went to New York University for my PhD.

During my PhD, I wrote code for the statistical analysis tool RooStats which is part of CERN’s Root Data Analysis tool. My ATLAS work was focused on the the H→ZZ*→4l analysis, the Higgs Combination and I was involved in the discovery (see New York Times article), the first mass measurement, the first evidence for VBF production and property measurements related to the coupling strengths of the Higgs Boson.

Here is a list of my side projects, my fairly empty blog and my outdated CV. Selected talks and papers are at the bottom of the page. My social media profiles are Twitter, LinkedIn and GitHub and my email address is me@svenkreiss.com.

Chasing the Higgs - The New York Times

My part of the Higgs discovery story in the New York Times.

Science Times section front page Chasing the Higgs, my part

That “joyful expletive” was “Holly shit” (not correcting the typo) sent from his phone.
Read the full story on the New York Times website from March 5, 2013.
The New Yorker also had a piece about our Nobel Prize Party.

A Novel Approach to Higgs Coupling Measurements (arXiv:1401.0080)

Kyle Cranmer, David Lopez-Val, Tilman Plehn and I are putting a very cool paper on arXiv:1401.0080 today.

We develop a technique to present Higgs coupling measurements, which decouple the poorly defined theoretical uncertainties associated to inclusive and exclusive cross section predictions. The technique simplifies the combination of multiple measurements and can be used in a more general setting. We illustrate the approach with toy LHC Higgs coupling measurements and a collection of new physics models.

We share all the software that was involved. That includes that we published the model files and a Mathematica notebook on figshare. We put all the code on github which can be used for new models or to reproduce all plots in the paper simply by typing make. We even have a little demo project that pulls three pre-made decoupled models from a webpage and recouples them and produces two plots of combined benchmark coupling models.

MorphDemo using d3.js

Preview of kd-tree based morphing algorithm This is an interactive demo for a new morphing algorithm with special properties that are motivated from Physics. It uses KD trees and kernel density estimates that are calculated in real time in this demo. All visualization is done using d3.js and custom code for KD trees and kernel densities in JavaScript.

Link: morphDemo.html, blog post

Selected Publications

I had major contributions to the discovery of the Higgs Boson at CERN, Switzerland, in 2012 and I am a co-author of the statistics software used for Higgs Boson studies, RooStats. Analyses that I worked on and plots that I made are part of publications in the journal Science, Physics Letters B and the Particle Data Group among others.

  • 01/2014: Cranmer, Kreiss, Lopez-Val, Plehn. A Novel Approach to Higgs Coupling Measurements. arXiv:1401.0080.
  • 07/2013: ATLAS collaboration. Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC. I was an editor. Inspire. Phys.Lett. B726 (2013) 88-119.
  • 07/2013: ATLAS collaboration. Evidence for the spin-0 nature of the Higgs boson using ATLAS data. Inspire. Phys.Lett. B726 (2013) 120-144.
  • 03/2013: ATLAS collaboration. Combined coupling measurements of the Higgs-like boson with the ATLAS detector using up to 25 fb−1 of proton-proton collision data. I was an editor for the main supporting document. Inspire.
  • 03/2013: ATLAS collaboration. Study of the spin of the new boson with up to 25 fb−1 of ATLAS data. Inspire.
  • 12/2012: ATLAS Collaboration. A Particle Consistent with the Higgs Boson Observed with the ATLAS Detector at the Large Hadron Collider. Science, vol 338, issue 6114, 1576-1582.
  • 07/2012: ATLAS Collaboration. Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC. CERN-PH-EP-2012-218, Phys.Lett. B716 (2012) 1-29, arXiv:1207.7214.
  • 07/2012: ATLAS Collaboration. Combined search for the Standard Model Higgs boson in pp collisions at √s = 7 TeV with the ATLAS detector. Phys.Rev. D86 (2012) 032003.
  • 02/2012: ATLAS collaboration. Combined search for the Standard Model Higgs boson using up to 4.9 fb⁻¹ of pp collision data at √s = 7 TeV with the ATLAS detector at the LHC. Phys.Lett. B710 (2012) 49-66, arXiv:1202.1408.
  • 12/2010: ATLAS collaboration. Measurement of the top quark pair production cross-section with ATLAS in pp collisions at √s = 7 TeV. Eur.Phys.J.C71:1577,2011, arXiv:1012.1792.
  • 10/2010: L. Moneta, K. Belasco, K.S. Cranmer, S. Kreiss, A. Lazzaro, et al. The RooStats Project. PoS (ACAT2010) 057.
  • 03/2008: M.M. Nojiri et al. Physics Beyond the Standard Model: Supersymmetry. SUSY working group report: Les Houches 2007. arXiv:0802.3672.
  • 01/2008: B.C. Allanach et al. SUSY Les Houches Accord 2. CPC 180 (2009) 1, arXiv:0801.0045.

On Inspire: Paper list, Author page.

Selected Talks

During my PhD studies, I gave talks in Hamburg, Goettingen and Dresden (Germany), Split (Croatia), Geneva (Switzerland), Rome (Italy), Cambridge (UK), Raleigh (NC, USA) and New York (NY, USA).

  • 01/2014: Factorizing Theoretical Uncertainties from LHC Higgs Coupling Measurements, Seminar, University of Cambridge, UK
  • 07/2013: Modeling and Statistical Analysis for Higgs Physics at the Large Hadron Collider, Knowledge Extraction via Comparison of Complex Computational Models to Massive Data Sets, Durham, NC, USA, Conference page, PDF
  • 01/2013: H→ZZ*→4l Likelihood in ATLAS, Likelihoods for the LHC Searches, CERN, Conference Indico, PDF
  • 10/2012: Standard Model Higgs Combination and Properties, LHC Days 2012, Split, Croatia, ATL-PHYS-SLIDE-2012-609
  • 05/2012: RooStats: Statistical Tools for the LHC, CHEP 2012, New York, Slides