Flavor-dependent U(1) extension inspired by lepton, baryon and color numbers by Duong Van Loi, Phung Van Dong

“…Abstract There is no reason why the gauge symmetry extension is family universal as in the standard model and the most well-motivated models, e.g. left-right symmetry and grand unification. Hence, we propose a simplest extension of the standard model – a flavor-dependent U(1) gauge symmetry – and find the new physics insight. …”
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String Axiverse by Arvanitaki, A, Dimopoulos, S, Dubovsky, S, Kaloper, N, March-Russell, J

“…This reach can be improved down to the grand unification scale f_a<2*10^16GeV, by observing smaller stellar mass black holes.…”

Baryogenesis: A Symmetry Breaking in the Primordial Universe Revisited by David S. Pereira, João Ferraz, Francisco S. N. Lobo, José P. Mimoso

“…Throughout the years, various mechanisms have been proposed to address this issue, and here we review two of the most important, namely, electroweak baryogenesis (EWB) and Grand Unification Theories (GUTs) baryogenesis. Furthermore, we briefly explore how a change in the theory of gravity affects the EWB and GUT baryogenesis by considering Scalar–Tensor Theories (STT), where the inclusion of a scalar field mediates the gravitational interaction, in addition to the metric tensor field. …”
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Non-supersymmetric SO(10) models with Gauge and Yukawa coupling unification by Abdelhak Djouadi, Renato Fonseca, Ruiwen Ouyang, Martti Raidal

“…Abstract We study a non-supersymmetric SO(10) Grand Unification Theory with a very high energy intermediate symmetry breaking scale in which not only gauge but also Yukawa coupling unification are enforced via suitable threshold corrections and matching conditions. …”
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Using C++ to Calculate SO(10) Tensor Couplings by Azadan Bhagwagar, Raza M. Syed

“…Model building in <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi mathvariant="sans-serif">SO</mi><mo>(</mo><mn mathvariant="sans-serif">10</mn><mo>)</mo></mrow></semantics></math></inline-formula>, which is the leading grand unification framework, often involves large Higgs representations and their couplings. …”
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Supersymmetry and electroweak fine tuning by Hardy, E

“…If stops are very light, the coupling of the singlet to the Higgs needs to be so large that it becomes nonperturbative before the scale of grand unification, raising the concern that precision gauge coupling unification may be upset. …”

The early universe from CMB B-modes: observational challenges by Azzoni, A

“…The potential of primordial B-modes to help identify what prompted inflation, whilst also investigating physics at grand unification energy scales, makes the search for this faint CMB polarization signal one of the most compelling goals of modern cosmology.…”

A New Route to Symmetries through the Extended Dirac Equation by Eckart Marsch, Yasuhito Narita

“…This new notion does not need the idea of grand unification. However, by still combining them in the product group <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>S</mi><mi>U</mi><mo>(</mo><mn>4</mn><mo>)</mo><mo>=</mo><mi>S</mi><mi>U</mi><mo>(</mo><mn>3</mn><mo>)</mo><mo>⊗</mo><mi>U</mi><mo>(</mo><mn>1</mn><mo>)</mo></mrow></semantics></math></inline-formula> and then further combining all groups into <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>S</mi><mi>U</mi><mo>(</mo><mn>2</mn><mo>)</mo><mo>⊗</mo><mi>S</mi><mi>U</mi><mo>(</mo><mn>4</mn><mo>)</mo></mrow></semantics></math></inline-formula>, one may get a symmetry scheme that perhaps supports the notion of unification by the group <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>S</mi><mi>U</mi><mo>(</mo><mn>8</mn><mo>)</mo></mrow></semantics></math></inline-formula>. …”
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Hadronic Isospin Helicity and the Consequent <i>SU</i>(4) Gauge Theory by Eckart Marsch, Yasuhito Narita

“…While our approach does not require the a priori concept of grand unification, such a notion arises naturally from the formulation with the isospin helicity. …”
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