Searching for heavy photons in the HPS Experiment
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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 e +e -, and targets the range in heavy photon mass m A' ~ 20 - 600 MeV, and kinetic mixing strength epsilon 2 ~ 10 -5 - 10 -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 nbmore »
- Authors:
-
- SLAC National Accelerator Lab., Menlo Park, CA (United States)
- Publication Date:
- Research Org.:
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26)
- OSTI Identifier:
- 1431175
- Report Number(s):
- JLAB-PHY-16-2462; DOE/OR/23177-4392
- DOE Contract Number:
- AC05-06OR23177
- Resource Type:
- Thesis/Dissertation
- Country of Publication:
- United States
- Language:
- English
Citation Formats
Uemura, Sho. Searching for heavy photons in the HPS Experiment. United States: N. p., 2016.
Web. doi:10.2172/1431175.
Uemura, Sho. Searching for heavy photons in the HPS Experiment. United States. doi:10.2172/1431175.
Uemura, Sho. Tue .
"Searching for heavy photons in the HPS Experiment". United States. doi:10.2172/1431175. https://www.osti.gov/servlets/purl/1431175.
@article{osti_1431175,
title = {Searching for heavy photons in the HPS Experiment},
author = {Uemura, Sho},
abstractNote = {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 e+e-, and targets the range in heavy photon mass mA' ~ 20 - 600 MeV, and kinetic mixing strength epsilon2 ~ 10-5 - 10-10. 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 nb-1, 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 mA' ~ 20 - 60 MeV, and kinetic mixing strength epsilon2 ~ 2 × 10-8 - 10-10. This search does not have sufficient sensitivity to exclude a canonical heavy photon at any combination of mA' and epsilon2. 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.},
doi = {10.2172/1431175},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Nov 01 00:00:00 EDT 2016},
month = {Tue Nov 01 00:00:00 EDT 2016}
}