Searching for heavy photons in the HPS experiment
Abstract/Contents
- Abstract
- The Heavy Photon Search (HPS) is a new experiment at Jefferson Lab that searches for a massive U(1) vector boson (known as a heavy photon or A') in the MeV-GeV mass range and coupling weakly to ordinary matter through a kinetic mixing interaction. The HPS experiment seeks to produce heavy photons by electron bremsstrahlung on a fixed target, is sensitive to heavy photon decays to electron-positron pairs, and targets the range in heavy photon mass from 20 to 600 MeV, and kinetic mixing strength epsilon^2 from 1E-5 to 1E-10. HPS searches for heavy photons using two signatures: a narrow mass resonance and displaced vertices. This dissertation presents the theoretical and experimental motivations for a heavy photon, the design and operation of the HPS experiment, and the displaced vertex search. The data used in this dissertation is the unblinded fraction of the 2015 HPS run, for the period of operation where the HPS silicon vertex tracker (SVT) was operated at its nominal position. This data was recorded from May 13 to May 18, 2015, at a beam energy of 1.056 GeV and a nominal beam current of 50 nA. The integrated luminosity is 119 inverse nanobarns, which is equivalent to 0.172 days of ideal running at the nominal beam current. This dissertation presents results (signal significance and upper limits) from the displaced vertex search in the mass range from 20 to 60 MeV, and kinetic mixing strength epsilon^2 from 2E-8 to 1E-10. This search does not have sufficient sensitivity to exclude a canonical heavy photon at any combination of mass and mixing strength. The strictest limit achieved in this analysis on the production of a particle that decays like a heavy photon is 115 times the expected production cross-section for a heavy photon. Factors limiting the sensitivity of this analysis are discussed. Projections of HPS performance with the full 2015 data set, and with planned improvements to the analysis, are presented. Comparisons are also made to earlier reach estimates.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2016 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Uemura, Sho | |
|---|---|---|
| Associated with | Stanford University, Department of Physics. | |
| Primary advisor | Jaros, John | |
| Thesis advisor | Jaros, John | |
| Thesis advisor | Burchat, P. (Patricia) | |
| Thesis advisor | Peskin, Michael Edward, 1951- | |
| Advisor | Burchat, P. (Patricia) | |
| Advisor | Peskin, Michael Edward, 1951- |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Sho Uemura. |
|---|---|
| Note | Submitted to the Department of Physics. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2016. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2016 by Sho Uemura
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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