Extracting bb Higgs Decay Signals using Multivariate Techniques
Description/Abstract
For low-mass Higgs boson production at ATLAS at {radical}s = 7 TeV, the hard subprocess gg {yields} h{sup 0} {yields} b{bar b} dominates but is in turn drowned out by background. We seek to exploit the intrinsic few-MeV mass width of the Higgs boson to observe it above the background in b{bar b}-dijet mass plots. The mass resolution of existing mass-reconstruction algorithms is insufficient for this purpose due to jet combinatorics, that is, the algorithms cannot identify every jet that results from b{bar b} Higgs decay. We combine these algorithms using the neural net (NN) and boosted regression tree (BDT) multivariate methods in attempt to improve the mass resolution. Events involving gg {yields} h{sup 0} {yields} b{bar b} are generated using Monte Carlo methods with Pythia and then the Toolkit for Multivariate Analysis (TMVA) is used to train and test NNs and BDTs. For a 120 GeV Standard Model Higgs boson, the m{sub h{sup 0}}-reconstruction width is reduced from 8.6 to 6.5 GeV. Most importantly, however, the methods used here allow for more advanced m{sub h{sup 0}}-reconstructions to be created in the future using multivariate methods.
| DOI | 10.2172/1049738 |
|---|---|
| Creator/Author: | Smith, W Clarke ; /George Washington U. /SLAC |
| Publication Date: | 2012 Aug 28 |
| OSTI Identifier: | OSTI ID: 1049738 |
| Report Number(s): | SLAC-TN-12-015 |
| DOE Contract Number: | AC02-76SF00515 |
| DOI: | 10.2172/1049738 |
| Other Number(s): | TRN: US1204576 |
| Resource Type: | Technical Report |
| Research Org: | SLAC National Accelerator Laboratory (SLAC) |
| Sponsoring Org: | US DOE Office of Science (DOE SC) |
| Subject: | 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ALGORITHMS; DECAY; HIGGS BOSONS; MASS RESOLUTION; MONTE CARLO METHOD; MULTIVARIATE ANALYSIS; PRODUCTION; STANDARD MODEL |
| Related Subject: | Experiment-HEP,OTHER |
| Country of Publication: | United States |
| Language: | English |
| Format: | Size: 21 pages |
| Availability: | http://www.slac.stanford.edu/cgi-wrap/pubpage?slac-tn-12-015.html |
| Update Date: | 2012 Dec 05 |
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