4,026 research outputs found

### New Formulas and Predictions for Running Masses at Higher Scales in MSSM

Including contributions of scale-dependent vacuum expectation values of Higgs
scalars, we derive new one-loop formulas analytically for running quark-lepton
masses at higher scales in MSSM. Apart from the gauge-coupling dependence being
different from earlier formulas, the third-generation- Yukawa-coupling effects
are absent in the masses of the first two generations. While predicting the
masses and $\tan\beta$ numerically, we also include two-loop effects.Comment: 9 pages Latex.Typos correcte

### Vanishing corrections on the intermediate scale and implications for unification of forces

In two-step breaking of a class of grand unified theories including SO(10),we
prove a theorem showing that the scale $M_I$ where the Pati-Salam gauge
symmetry with parity breaks down to the standard gauge group,has vanishing
corrections due to all sources emerging from higher scales $\mu >M_I$ such as
the one-loop and all higher loop effects,the GUT-threshold,gravitational
smearing,and string threshold effects. Implications of such a scale for the
unification of gauge couplings with small Majorana neutrino masses are
discussed.In string inspired SO(10) we show that $M_I \simeq 5\times
10^{12}$,needed for neutrino masses,with the GUT scale $M_U \simeq M_{str}$ can
be realized provided certain particle states in the predicted spectum are
light.Comment: 21 pages, Late

### New Formulas and Predictions for Running Fermion Masses at Higher Scales in SM, 2HDM, and MSSM

Including contributions of scale-dependent vacuum expectation values, we
derive new analytic formulas and obtain substantially different numerical
predictions for the running masses of quarks and charged-leptons at higher
scales in the SM, 2HDM and MSSM. These formulas exhibit significantly different
behaviours with respect to their dependence on gauge and Yukawa couplings than
those derived earlier. At one-loop level the masses of the first two
generations are found to be independent of Yukawa couplings of the third
generation in all the three effective theories in the small mixing limit.
Analytic formulas are also obtained for running $\tan\beta(\mu)$ in 2HDM and
MSSM. Other numerical analyses include study of the third generation masses at
high scales as functions of low-energy values of $\tan\beta$ and SUSY scale
$M_S=M_Z-10^4$ GeV.Comment: 42 pages RevTeX, including 16 figures. Typos corrected and one
reference adde

### Neutrino Mass, Coupling Unification, Verifiable Proton Decay, Vacuum Stability and WIMP Dark Matter in SU(5)

Nonsupersymmetric minimal SU(5) with Higgs representations ${24}_H$ and $5_H$
and standard fermions in ${\bar 5}_F\oplus {10}_F$ is well known for its
failure in unification of gauge couplings and lack of predicting neutrino
masses. Like standard model, it is also affected by the instability of the
Higgs scalar potential. We note that extending the Higgs sector by ${75}_H$ and
${15}_H$ not only leads to the popular type-II seesaw ansatz for neutrino
masses with a lower bound on the triplet mass $M_{\Delta} > 2\times 10^9$ GeV,
but also achieves precision unification of gauge couplings without
proliferation of non-standard light Higgs scalars or fermions near the TeV
scale. Consistent with recent LUX-2016 lower bound, the model easily
accommodates a singlet scalar WIMP dark matter near the TeV scale which
resolves the vacuum stability issue even after inclusion of heavy triplet
threshold effect. We estimate proton lifetime predictions for $p\to e^+\pi^0$
including uncertainties due to input parameters and threshold effects due to
superheavy Higgs scalars and superheavy $X^{\pm 4/3},Y^{\pm 1/3}$ gauge bosons.
The predicted lifetime is noted to be verifiable at Super Kamiokande and Hyper
Kamiokande experiments.Comment: 36 pages, 9 figures (Accepted for publication in Advances in High
Energy Physics

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