Prospecting for new physics in the Higgs and flavor sectors

Thesis/Dissertation · Fri May 01 00:00:00 EDT 2015

DOI:https://doi.org/10.2172/1212175· OSTI ID:1212175

Bishara, Fady ^[1]

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1. Univ. of Cincinnati, OH (United States)

We explore two directions in beyond the standard model physics: dark matter model building and probing new sources of CP violation. In dark matter model building, we consider two scenarios where the stability of dark matter derives from the flavor symmetries of the standard model. The first model contains a flavor singlet dark matter candidate whose couplings to the visible sector are proportional to the flavor breaking parameters. This leads to a metastable dark matter with TeV scale mediators. In the second model, we consider a fully gauged SU(3)³ flavor model with a flavor triplet dark matter. Consequently, the dark matter multiplet is charged while the standard model fields are neutral under a remnant Z₃ which ensures dark matter stability. We show that a Dirac fermion dark matter with radiative splitting in the multiplet must have a mass in the range [0:5; 5] TeV in order to satisfy all experimental constraints. We then turn our attention to Higgs portal dark matter and investigate the possibility of obtaining bounds on the up, down, and strange quark Yukawa couplings. If Higgs portal dark matter is discovered, we find that direct detection rates are insensitive to vanishing light quark Yukawa couplings. We then review flavor models and give the expected enhancement or suppression of the Yukawa couplings in those models. Finally, in the last two chapters, we develop techniques for probing CP violation in the Higgs coupling to photons and in rare radiative decays of B mesons. While theoretically clean, we find that these methods are not practical with current and planned detectors. However, these techniques can be useful with a dedicated detector (e.g., a gaseous TPC). In the case of radiative B meson decay B⁰ → (K* → Kππ) γ, the techniques we develop also allow the extraction of the photon polarization fraction which is sensitive to new physics contributions since, in the standard model, the right(left) handed polarization fraction is of O( Λ_QCD=m_b) for $$\bar{B}^{0}$$(B⁰) meson decays.

• Research Organization: Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
• Sponsoring Organization: USDOE Office of Science (SC), High Energy Physics (HEP)
• DOE Contract Number: AC02-07CH11359
• OSTI ID: 1212175
• Report Number(s): FERMILAB-THESIS-2015-10; TRN: US1601302
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
B NEUTRAL MESONS
FLAVOR MODEL
RADIATIVE DECAY
NONLUMINOUS MATTER
HIGGS MODEL
C QUARKS
D QUARKS
S QUARKS
U QUARKS
HIGGS BOSONS
CP INVARIANCE
KAONS
PIONS
PHOTONS
TEV RANGE
COUPLINGS
SYMMETRY BREAKING
POLARIZATION
PROBES
STABILITY
TRIPLETS
LIMITING VALUES
DETECTION
INHIBITION
MASS
SYMMETRY
SU-3 GROUPS
YUKAWA NONLOCAL THEORY