1 / 23

Perturbation Theory and Mixture Models: Application to Particle Physics ACAS 21 Oct 2004

Perturbation Theory and Mixture Models: Application to Particle Physics ACAS 21 Oct 2004. Cyrus Taylor Dept. of Physics Case Western Reserve University cct@case.edu (work joint with C. Loader and R. Pilla). Outline.

zlhna
Download Presentation

Perturbation Theory and Mixture Models: Application to Particle Physics ACAS 21 Oct 2004

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Perturbation Theory and Mixture Models: Application to Particle Physics ACAS21 Oct 2004 Cyrus Taylor Dept. of Physics Case Western Reserve University cct@case.edu (work joint with C. Loader and R. Pilla)

  2. Outline • Review of score + formula for asymptotic distribution – do we need additional parameters to describe the data? • Applications to particle physics • Ex: search for new particle resonances • Ex: energy spectrum of highest energy cosmic rays

  3. Mixture models, score statistic and its asymptotic distribution • Mixture models: • Score statistic • where

  4. Asymptotic distribution • described by d-dimensional volume of manifold expressible through covariance function

  5. Ex: search for new resonances • What are physicists searching for? • Why are we searching for it? • How do we search for it?

  6. Ex: Pentaquarks • QCD – nobel prize • Q q-bar, 3 q states • Pentaquark discovered • Charmed pentaquarks • H1 claims discovery; Zeus doesn’t see it

  7. H1 detector

  8. Pentaquark in H1 setup e 27,6 GeV p 820/920 GeV K p

  9. Ex: pentaquarks

  10. Mixture models in particle physics • Background : power law • Perturbation (resonance): Breit-Wigner (Cauchy):

  11. Application of score analysis (MC) • 10% mixture • 50% mixture • Model parameters:

  12. T:

  13. Surface of normalized score process

  14. Power of and normalized score

  15. Search for Higgs Search for SUSY Search for the unexpected Next: LHC

  16. Cosmic Rays • spectrum

  17. High End of spectrum

  18. Greissen cutoff • Shouldn’t be any very high energy cosmic rays – interactions with microwave background radiation • Where are they coming from? New sources? • Auger project: $50 million air shower array

  19. Auger…New component?

  20. Score sensitivity for power-law mix • Ex: slightly softer (~2.7 added in at 20% level); cut off at region where disagreement begins

  21. Sensitivity

  22. Conclusions • Score test statistic + asymptotic distribution represents a powerful new tool for the search for new physics in high energy physics and particle astrophysics

More Related