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It is notorious that, contrary to all other precision electroweak data, the forward-backward asymmetry for b quarks $A_{FB}^b$ measured in Z decays at LEP1 is nearly three standard deviations away from the predicted value in the Standard…

High Energy Physics - Phenomenology · Physics 2008-11-26 Abdelhak Djouadi , Gregory Moreau , Francois Richard

We present selected results of our program to determine the masses, gauge couplings, and Yukawa couplings of the minimal supersymmetric model in a full one-loop calculation. We focus on the precise prediction of the strong coupling…

High Energy Physics - Phenomenology · Physics 2007-05-23 Jonathan Bagger , Konstantin Matchev , Damien Pierce

This report is a review of the present status of GUT, especially renormalizable minimal SO(10) GUT, and its future prospect. It consists of two parts. In part I, I review how the minimal renormalizable supersymmetric SO(10) GUT, an SO(10)…

High Energy Physics - Phenomenology · Physics 2009-03-20 Takeshi Fukuyama

Grand unified theories often predict unification of Yukawa couplings (e.g., $h_{b} = h_{\tau}$), and thus certain relations among fermion masses. The latter can distinguish these from models that predict only coupling constant unification.…

High Energy Physics - Phenomenology · Physics 2009-10-22 Paul Langacker , Nir Polonsky

Grand unification of gauge couplings and fermionic representations remains an appealing proposal to explain the seemingly coincidental structure of the Standard Model. However, to realise the Standard Model at low energies, the unified…

High Energy Physics - Phenomenology · Physics 2022-08-16 Aaron Held , Jan Kwapisz , Lohan Sartore

The requirement of t-b-\tau Yukawa coupling unification is common in simple grand unified models based on the gauge group SO(10), and it also places a severe constraint on the expected spectrum of superpartners. For Yukawa-unified models…

High Energy Physics - Phenomenology · Physics 2009-05-08 Howard Baer , Sabine Kraml , Sezen Sekmen , Heaya Summy

We discuss the low energy implications of gauge coupling unification at the string scale, taking into account string threshold corrections in the $SU(4) {\times} O(4)$ model. We express $sin^2\theta_W$ and $a_3$ as functions of the…

High Energy Physics - Phenomenology · Physics 2009-10-28 G. K. Leontaris , N. D. Tracas

We present a measurement of the forward-backward charge asymmetry ($A_{FB}$) in $p\bar{p} \to Z/\gamma^{*}+X \to e^+e^-+X$ events at a center-of-mass energy of 1.96 TeV using 1.1 fb$^{-1}$ of data collected with the D0 detector at the…

High Energy Physics - Experiment · Physics 2008-12-18 D0 Collaboration , V. M. Abazov

Forward-backward asymmetry $A_{\rm FB}$ is an essential observable to study the nature of coupling in the standard model and physics beyond the standard model, as shown at LEP and Tevatron. As a proton-proton collider, the LHC does not have…

High Energy Physics - Phenomenology · Physics 2011-02-01 You-kai Wang , Bo Xiao , Shou-hua Zhu

The presence of a colored scalar that is a weak doublet with fractional electric charges of $|Q|=2/3$ and $|Q|=5/3$ with mass below 1,TeV can provide an explanation of the observed branching ratios in $B \to D^{(*)} \tau \bar \nu$ decays.…

High Energy Physics - Phenomenology · Physics 2015-06-16 Ilja Dorsner , Svjetlana Fajfer , Nejc Kosnik , Ivan Nisandzic

We find that the tree-level predictions of the forward-backward production asymmetries on the Z resonance for b and c quarks, A_FB, in an SO(5) x U(1) gauge-Higgs unification model are markedly close to the central values of the Particle…

High Energy Physics - Phenomenology · Physics 2010-07-30 Nobuhiro Uekusa

The objective of this study is to correlate the scaling factor of the Standard Model (SM) like Higgs boson and the cross section ratio of the process $e^+ e^- \rightarrow hhf\overline{f}$ where $f\neq t$, normalized to SM predictions in the…

High Energy Physics - Phenomenology · Physics 2021-06-15 Ijaz Ahmed , Sehrish Gul , Taimoor Khurshid

Supersymmetric grand unified models based on the gauge group SU(5) often require in addition to gauge coupling unification, the unification of b-quark and $\tau$-lepton Yukawa couplings. We examine SU(5) SUSY GUT parameter space under the…

High Energy Physics - Phenomenology · Physics 2015-06-03 Howard Baer , Ilia Gogoladze , Azar Mustafayev , Shabbar Raza , Qaisar Shafi

We study the properties and production mechanisms of color-octet scalars at the LHC. We focus on the single production of both charged and neutral members of an (8,2)_1/2 doublet through bottom quark initial states. These channels provide a…

High Energy Physics - Phenomenology · Physics 2009-01-08 Pavel Fileviez Pérez , Ryan Gavin , Thomas McElmurry , Frank Petriello

We consider the scenario in which the mass matrices of the charged fermions in the SO(10) Grand Unified Theory are generated exclusively by renormalizable Yukawa couplings to one $\mathbf{10} \oplus \mathbf{120}$ representation of scalars.…

High Energy Physics - Phenomenology · Physics 2011-01-27 L. Lavoura , H. Kuhbock , W. Grimus

The W-mass anomaly has yet to be established, but a huge proliferation of articles on the subject established the rich potential of such event. We investigate the SO(10) GUT constraints from the recently reported W-mass anomaly. We consider…

High Energy Physics - Phenomenology · Physics 2023-09-26 Purushottam Sahu , Hiranmaya Mishra , Prasanta K. Panigrahi , Sudhanwa Patra , Utpal Sarkar

I analyze the predictions for the strong gauge coupling, $\alpha_3(M_Z) $, and the top quark and light Higgs masses in the framework of gauge and bottom-tau Yukawa coupling unification in the minimal supersymmetric standard model. These…

High Energy Physics - Phenomenology · Physics 2007-05-23 M. Carena

We make a comprehensive analysis of an extended supersymmetric model(ESSM) obtained by adding a pair of vector-like families to the minimal supersymmetric standard model and having specific forms of 5 x 5 fermion mass matrices. The singlet…

High Energy Physics - Phenomenology · Physics 2009-10-31 Mar Bastero-Gil , Biswajoy Brahmachari

We show that in the CMSSM with the non-holomorphic soft SUSY breaking terms, the Yukawa coupling unification of the third family fermions at the GUT scale, called $ t-b-\tau $ Yukawa unification (YU), is possible under the recent collider…

High Energy Physics - Phenomenology · Physics 2021-05-12 Yaşar Hiçyılmaz

We consider $b$-$\tau$ unification in supersymmetric $SU(5)$ grand unified theories (GUTs) with extra matters. The renormalization group runnings of $b$ and $\tau$ Yukawa coupling constants may be significantly affected by the existence of…

High Energy Physics - Phenomenology · Physics 2018-03-13 So Chigusa , Takeo Moroi