Shaikh Saad

Predictive Non-Minimal SU(5) GUT

Ilja Doršner, Mijo Matković, Shaikh Saad

Breaking of $S U (5)$ down to the Standard Model gauge group can be implemented by any non-trivial self-conjugate scalar representation with a suitable vacuum expectation value. The…

Large Language Model-Assisted Framework for BSM Model Building

Shaikh Saad

Recent advances in artificial intelligence (AI), particularly large language models (LLMs), have created new opportunities for natural-language interaction with scientific software…

Weak Triplet Models of Neutrino Magnetic Moments

Svjetlana Fajfer, Shaikh Saad

Experimental limits on neutrino magnetic moments remain several orders of magnitude above the predictions of the Standard Model; therefore, any future detection would provide unamb…

Towards Precision Neutrino Fits in GUTs: Relevance of One-Loop Finite Corrections

Chee Sheng Fong, Shaikh Saad

In this work, we perform a dedicated analysis of fermion mass fits in the minimal $S O (10)$ grand unified theory (GUT), going beyond the tree-level approximation by incorporating on…

Reality-constrained Minimal Yukawa Structure in SO(10) GUT

Shaikh Saad, Vasja Susič

We investigate the minimal Yukawa sector of $SO (10)$ grand unified theories with Higgs representations $\mathbf{10}_{\mathbb{R}}\oplus\mathbf{120}_{\mathbb{R}}\oplus\mathb…

TeV Scale Quark-Lepton Unification

K. S. Babu, Sumit Biswas, Shaikh Saad

We propose a quark-lepton symmetric Pati-Salam (PS) model based on the gauge group $S U (2)_{L} \times S U (2)_{R} \times S U (4)_{C}$ with an $E_{6}$ -inspired particle spectrum which naturally…

Neutrino masses, $δ_{PMNS}$ , and $m_{β β}$ in SO(10)

Shaikh Saad, Qaisar Shafi

We explore the leptonic sector of a recently proposed supersymmetric SO(10) model with supersymmetry breaking in the 3-10 TeV range. A new ingredient in this work is the requiremen…

hep-ph2025★ 1 cited

Neutrino Mass Induced $n$ - $n$ Oscillation

Ilja Dorsner, Svjetlana Fajfer, Shaikh Saad

The Georgi-Glashow model is the simplest possible attempt at grand unification. However, due to its particle content, the model preserves a global $U (1)_{B - L}$ symmetry, where $B$ …

Updated Running Quark and Lepton Parameters at Various Scales

Stefan Antusch, Kevin Hinze, Shaikh Saad

In the light of the recent Particle Data Group (PDG) release, we revisit the running quark and lepton Yukawa couplings, together with the quark mixing parameters, across a range of…

Beyond Neutrino Mass: Observable $n$ - $n$ Oscillations in UV Complete Seesaw Models

Ilja Dorsner, Svjetlana Fajfer, Shaikh Saad

Next-generation experiments, such as the Deep Underground Neutrino Experiment and the European Spallation Source, are set to improve sensitivity to neutron-antineutron oscillation,…

A new perspective on the CMSSM: Yukawa Unification, DM and the SUSY scale

Stefan Antusch, Shaikh Saad, Vasja Susič

What does third family ( $t$ - $b$ - $τ$ ) Yukawa unification, a typical prediction from embedding the Standard Model (SM) fermions in 16-plets of a $SO (10)$ GUT, imply for the…

One Phase to Rule Them All: Spontaneous CP Violation and Leptogenesis in SO(10)

K. S. Babu, Chee Sheng Fong, Shaikh Saad

We present a renormalizable $S O (10)$ grand unified theory with a minimal Yukawa sector consisting of a $12 6_{H}$ , a real $1 0_{H}$ and a real $12 0_{H}$ , where $C P$ violation has a spontan…

Fermion masses and mixings in supersymmetric SO(10) with third-generation quasi-Yukawa unification

Shaikh Saad, Qaisar Shafi

We discuss the charged and neutral fermion masses and mixings in a supersymmetric SO(10) model with a minimal Higgs sector consisting of the multiplets $1 0_{H}$ , $4 5_{H}$ , and $16_H +…

Non-Renormalizable SU(5) GUTs: Leptoquark-Induced Neutrino Masses

Ilja Doršner, Mijo Matković, Shaikh Saad

We revisit the doublet-triplet splitting problem within the $S U (5)$ gauge group framework to advocate a viable regime with the light scalar leptoquark of the doublet-triplet splitt…

Metastable Cosmic Strings and Gravitational Waves from Flavour Symmetry Breaking

Stefan Antusch, Kevin Hinze, Shaikh Saad

Metastable cosmic strings (MSCSs) are among the best-fitting explanations of the 2023 pulsar timing array (PTA) signal for gravitational waves at nanohertz frequencies. We propose…

Ultraviolet Completion of a Two-loop Neutrino Mass Model

K. S. Babu, Shaikh Saad

The Zee-Babu model is an economical framework for neutrino mass generation as two-loop quantum corrections. In this work, we present a UV completion of this model by embedding it i…

Leptogenesis in SO(10) with Minimal Yukawa sector

K. S. Babu, Pasquale Di Bari, Chee Sheng Fong +1

In prior studies, a very minimal Yukawa sector within the $S O (10)$ Grand Unified Theory framework has been identified, comprising of Higgs fields belonging to a real $1 0_{H}$ , a real…

Unified Origin of Inflation, Baryon Asymmetry, and Neutrino Mass

Ajay Kaladharan, Shaikh Saad

In this work, we present a unified theoretical framework that simultaneously addresses some of the most intriguing puzzles in particle physics and cosmology, namely the origins of…

Explaining PTA Results by Metastable Cosmic Strings from SO(10) GUT

Stefan Antusch, Kevin Hinze, Shaikh Saad

In a recent paper (see https://doi.org/10.1103/PhysRevD.108.095053), we have demonstrated that the 2023 PTA results, which hint at a stochastic gravitational wave (GW) background a…

Probing SUSY at Gravitational Wave Observatories

Stefan Antusch, Kevin Hinze, Shaikh Saad +1

Under the assumption that the recent pulsar timing array evidence for a stochastic gravitational wave (GW) background at nanohertz frequencies is generated by metastable cosmic str…

Is Doublet-Triplet Splitting Necessary?

Ilja Doršner, Shaikh Saad

We demonstrate that it is not necessary to substantially break the mass degeneracy between the Standard Model Higgs boson doublet and the corresponding scalar leptoquark, where the…

Leptoquark-Mediated Two-Loop Neutrino Mass in Unified Theory

Kevin Hinze, Shaikh Saad

Scalar leptoquarks naturally arise within unified theories, offering a promising avenue for addressing one of the most significant challenges of the Standard Model--the existence o…