Supersymmetric grand unified models based on the SO(10) gauge group are especially
attractive in light of recent data on neutrino masses. The simplest SO(10) SUSY GUT
models predict unification of third generation Yukawa couplings (t –b – Ƭ) in addition
to the usual gauge coupling unification. An assessment of the viability of such Yukawa
unified models is presented. For the superpotential Higgs mass parameter μ>0, it is
found that unification to less than 1% is possible, but only for GUT scale scalar mass
parameter m16 ~ 8 – 20 TeV, and small values of gaugino mass m1/2 ≤ 150 GeV. Such models
require tha a GUT scale mass splitting exists amongst Higgs scalars with m2Hu < m2Hd.
Viable solutions lead to a radiatively generated inverted scalar mass hierarchy, with
third generation and Higgs scalars being lighter than other sfermions. These models have
a very heavy sfermions, so that unwanted flavor changing and CP violating SUSY processes
are suppressed, but may suffer from some fine-tuning requirements. While the generated
spectra satisify b → sγ and (g – 2)μ constraints, there exists tension with the dark
matter relic density unless m16 ≤ 3TeV. These models offer prospects for SUSY discovery
at the Fermilab Tevatron collider via the search for W1Z2 → 3l events, or via gluino
pair production. If μ < 0, Yujawa coupling unification to less than 5% can occur for
m16 and m 1/2≥ 1 – 2 TeV. Consistency of negative μ Yukawa unified models with b → sγ,
(g – 2)μ, and relic density Ωh2 all imply very large values of m1/2 typically greater
than about 2.5 TeV, in which case direct dection of sparticles may be a challenge even
at the LHC. To address the tension between Yukawa unification and the excess of dark
matter that the μ>0 models tend to predict, a couple of possible improvements are
surveyed. One solution- lowering the GUT scale mass value of first and second generation
scalars, leads to uR and cR squark masses in the 90 – 120 GeV regime, which should be
accessible to Fermilab Tavatron experiments. Another possibility is relaxing gaugino
mass universality which may solve the relic density problem by having neutralino
annihilations via the Z or h resonances, or by having a wino-like LSP. / A Dissertation submitted to the Department of Physics in partial fulfillment of the
requirements for the degree of Doctor of Philosophy. / Degree Awarded: Fall Semester, 2004. / Date of Defense: August 31, 2004. / SUSY, GUT, Supersymmetry Phenomenology, Supersymmetric Standard Model, Yukawa Unification, SO(10) Symmetry / Includes bibliographical references. / Howard Baer, Professor Directing Dissertation; Christopher Hunter, Outside Committee Member; Laura Reina, Committee Member; Harrison Prosper, Committee Member; Jorge Piekarewicz, Committee Member.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_168079 |
| Contributors | Auto, Daniel M. (authoraut), Baer, Howard (professor directing dissertation), Hunter, Christopher (outside committee member), Reina, Laura (committee member), Prosper, Harrison (committee member), Piekarewicz, Jorge (committee member), Department of Physics (degree granting department), Florida State University (degree granting institution) |
| Publisher | Florida State University |
| Source Sets | Florida State University |
| Language | English, English |
| Detected Language | English |
| Type | Text, text |
| Format | 1 online resource, computer, application/pdf |
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