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Title: The HPS experiment

Abstract

With the experimental discovery of the Higgs boson, the Standard Model has been considered veri ed in all its previsions. The Standard Model, though, is still considered an incomplete theory, because it fails to address many theoretical and phenomenological issues. Among those, it doesn't provide any viable Dark Matter candidate. Many Beyond-Standard Model theories, such as the Supersymmetric Standard Model, provide possible solutions. In this work we have reported the experimental observations that led to considerate the existence of a new Force, mediated by a new massive vector boson, that could address all the observed phenomenology. This new dark Force could open an observational channel between the Standard Model and a new Dark Sector, convey by the interaction of the Standard Model photon with the massive dark photon, also called the A'. Purpose of this work was to develop an independent study of the background processes and the implementation of an independent event generator, to better understand the kinematics of the produced particles in the process e - +W → e - +W' + e + + e - and validate, or invalidate, the o cial event generator.

Authors:
 [1]
  1. National Inst. of Nuclear Physics (INFN), Rome (Italy)
Publication Date:
Research Org.:
Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26)
OSTI Identifier:
1408896
Report Number(s):
JLAB-PHY-17-2597; DOE/OR/23177-4264
DOE Contract Number:
AC05-06OR23177
Resource Type:
Thesis/Dissertation
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS

Citation Formats

Colaneri, Luca. The HPS experiment. United States: N. p., 2017. Web. doi:10.2172/1408896.
Colaneri, Luca. The HPS experiment. United States. doi:10.2172/1408896.
Colaneri, Luca. Sat . "The HPS experiment". United States. doi:10.2172/1408896. https://www.osti.gov/servlets/purl/1408896.
@article{osti_1408896,
title = {The HPS experiment},
author = {Colaneri, Luca},
abstractNote = {With the experimental discovery of the Higgs boson, the Standard Model has been considered veri ed in all its previsions. The Standard Model, though, is still considered an incomplete theory, because it fails to address many theoretical and phenomenological issues. Among those, it doesn't provide any viable Dark Matter candidate. Many Beyond-Standard Model theories, such as the Supersymmetric Standard Model, provide possible solutions. In this work we have reported the experimental observations that led to considerate the existence of a new Force, mediated by a new massive vector boson, that could address all the observed phenomenology. This new dark Force could open an observational channel between the Standard Model and a new Dark Sector, convey by the interaction of the Standard Model photon with the massive dark photon, also called the A'. Purpose of this work was to develop an independent study of the background processes and the implementation of an independent event generator, to better understand the kinematics of the produced particles in the process e- +W → e- +W' + e+ + e- and validate, or invalidate, the o cial event generator.},
doi = {10.2172/1408896},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sat Apr 01 00:00:00 EDT 2017},
month = {Sat Apr 01 00:00:00 EDT 2017}
}

Thesis/Dissertation:
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  • 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 massmore » 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 m_A' ~ 20 - 60 MeV, and kinetic mixing strength epsilon^2 ~ 2 × 10^-8 - 10^-10. This search does not have sufficient sensitivity to exclude a canonical heavy photon at any combination of m_A' and epsilon^2. 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 HPSperformance with the full 2015 data set, and with planned improvements to theanalysis, are presented. Comparisons are also made to earlier reach estimates.« less
  • This thesis presents a neural network search for combined as well as separate s- and t-channel single top-quark production with the CDF II experiment at the Tevatron using 3.2 fb -1 of collision data. It is the twelfth thesis dealing with single top-quark production performed within the CDF Collaboration, whereas three have been done in Run I [53–55] and eight in Run II [23, 25, 28, 39, 56–59].
  • Aus was besteht die Welt? Die Frage nach den fundamentalen Bausteinen der Materie beschaftigte Wissenschaftler und Gelehrte zu allen Zeiten. Ausgehend von abstrakten philosophischen Uberlegungen wurde das Konzept von kleinsten, nicht weiter zerteilbaren Grundbausteinen der Materie bereits einige Jahrhunderte vor Christus von indischen und griechischen Philosophieschulen entwickelt. Etwa 450 v. Chr. pragte Demokrit den Begriff ´atomos, das “Unzerschneidbare”, fur die diskreten Grundbausteine der Materie. Doch erst in der jungeren Vergangenheit konnte dieses philosophische Konzept auch experimentell uberpruft werden.
  • This dissertation describes two different projects from two different experiments. We have performed a search for CPT violation in neutral charm meson oscillations using data from the FOCUS Experiment. While flavor mixing in the charm sector is predicted to be small in the Standard Model, it is still possible to investigate CPT violation through a study of the proper time dependence of a CPT asymmetry in right-sign decay rates for D 0 → K - π + andmore » $$\bar{D}$$ 0 → K +π -. This asymmetry is related to the CPT violating complex parameter ξ and the mixing parameters x and y: A CPT ∞ Reξy - Imξx. We determine a 95% confidence level limit of -0.0068 < Reξy - Imξx < 0.0234. Within the framework of the Standard Model Extension incorporating general CPT violation, we also find 95% confidence level limits for the expressions involving coefficients of Lorentz violation of (-2.8 < N(x,y,δ))(Δa 0 + 0.6 Δa Z< 4.8) x 10 -16 GeV, (-7.0 < N(x,y,δ)Δa x < 3.8) x 10 -16 GeV, and (-7.0 < N(x,y,δ)Δa y < 3.8) x 10 -16 GeV, where N(x,y,δ) is a normalization factor that incorporates mixing parameters x, y and the doubly Cabibbo suppressed to Cabibbo favored relative strong phase δ.« less