| 1. |
- Boucenna, Sofiane M., et al.
(författare)
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A minimal non-supersymmetric SO(10) model with Peccei-Quinn symmetry
- 2019
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Ingår i: Physics Letters B. - : Elsevier. - 0370-2693 .- 1873-2445. ; 792, s. 251-257
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Tidskriftsartikel (refereegranskat)abstract
- We present a minimal non-supersymmetric SO(10) GUT breaking directly to the Standard Model gauge group. Precise gauge coupling unification is achieved due to the presence of two color-octet scalars, one of which is accessible to LHC searches. Proton lifetime is predicted to be below 4.5 x 10(34) years, which is within the projected five-year sensitivity of the proposed Hyper-Kamiokande experiment. We find that the Standard Model observables are reproduced to a reasonable accuracy in a numerical fit, which also predicts the unknown neutrino parameters. Finally, the two scalar representations stabilize the electroweak vacuum and the dark matter is comprised of axions.
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| 2. |
- Lindestam, Malte, et al.
(författare)
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Flavor symmetries in an SU(5) model of grand unification
- 2022
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Ingår i: Journal of High Energy Physics (JHEP). - : Springer Nature. - 1126-6708 .- 1029-8479. ; :1
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the options for imposing flavor symmetries on a minimal renormalizable non-supersymmetric SU(5) grand unified theory, without introducing additional flavor-related fields. Such symmetries reduce the number of free parameters in the model and therefore lead to more predictive models. We consider the Yukawa sector of the Lagrangian, and search for all possible flavor symmetries. As a result, we find 25 distinct realistic flavor symmetry cases, with DOUBLE-STRUCK CAPITAL Z(2), DOUBLE-STRUCK CAPITAL Z(3), DOUBLE-STRUCK CAPITAL Z(4), and U(1) symmetries, and no non-Abelian cases.
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| 3. |
- Mahdi, A., et al.
(författare)
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The red blood cell as a mediator of endothelial dysfunction in patients with familial hypercholesterolemia and dyslipidemia
- 2023
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Ingår i: Journal of Internal Medicine. - : Wiley. - 0954-6820 .- 1365-2796. ; 293:2, s. 228-245
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Tidskriftsartikel (refereegranskat)abstract
- Background Patients with familial hypercholesterolemia (FH) display high levels of low-density lipoprotein cholesterol (LDL-c), endothelial dysfunction, and increased risk of premature atherosclerosis. We have previously shown that red blood cells (RBCs) from patients with type 2 diabetes induce endothelial dysfunction through increased arginase 1 and reactive oxygen species (ROS). Objective To test the hypothesis that RBCs from patients with FH (FH-RBCs) and elevated LDL-c induce endothelial dysfunction. Methods and results FH-RBCs and LDL-c >5.0 mM induced endothelial dysfunction following 18-h incubation with isolated aortic rings from healthy rats compared to FH-RBCs and LDL-c <2.5 mM or RBCs from healthy subjects (H-RBCs). Inhibition of vascular but not RBC arginase attenuated the degree of endothelial dysfunction induced by FH-RBCs and LDL-c >5.0 mM. Furthermore, arginase 1 but not arginase 2 was elevated in the vasculature of aortic segments after incubation with FH-RBCs and LDL-c >5.0 mM. A superoxide scavenger, present throughout the 18-h incubation, attenuated the degree of endothelial dysfunction induced by FH-RBCs and LDL-c >5.0 mM. ROS production was elevated in these RBCs in comparison with H-RBCs. Scavenging of vascular ROS through various antioxidants also attenuated the degree of endothelial dysfunction induced by FH-RBCs and LDL-c >5.0 mM. This was corroborated by an increase in the lipid peroxidation product 4-hydroxynonenal. Lipidomic analysis of RBC lysates did not reveal any significant changes across the groups. Conclusion FH-RBCs induce endothelial dysfunction dependent on LDL-c levels via arginase 1 and ROS-dependent mechanisms.
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| 4. |
- Meloni, Davide, et al.
(författare)
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Threshold effects in SO(10) models with one intermediate breaking scale
- 2020
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Ingår i: European Physical Journal C. - : SPRINGER. - 1434-6044 .- 1434-6052. ; 80:9
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Tidskriftsartikel (refereegranskat)abstract
- Despite the successes of the Standard Model of particle physics, it is known to suffer from a number of deficiencies. Several of these can be addressed within non-supersymmetric theories of grand unification based on SO(10). However, achieving gauge coupling unification in such theories is known to require additional physics below the unification scale, such as symmetry breaking in multiple steps. Many such models are disfavored due to bounds on the proton lifetime. Corrections arising from threshold effects can, however, modify these conclusions. We analyze all seven relevant breaking chains with one intermediate symmetry breaking scale, assuming the "survival hypothesis" for the scalar masses. Two are allowed by proton lifetime and two are disfavored by a failure to unify the gauge couplings. The remaining three unify at a too low scale, but can be salvaged by various amounts of threshold corrections. We parametrize this and thereby rank the models by the size of the threshold corrections required to save them.
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| 5. |
- Ohlsson, Tommy, 1973-, et al.
(författare)
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Fits to non-supersymmetric SO(10) models with type I and II seesaw mechanisms using renormalization group evolution
- 2019
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Ingår i: Journal of High Energy Physics (JHEP). - : SPRINGER. - 1126-6708 .- 1029-8479. ; :6
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Tidskriftsartikel (refereegranskat)abstract
- We consider numerical fits to non-supersymmetric SO(10)-based models in which neutrino mass is generated by the type-I or type-II seesaw mechanism or a combination of both. The fits are performed with a sophisticated top-down procedure, taking into account the renormalization group equations of the gauge and Yukawa couplings, integrating out relevant degrees of freedom at their corresponding mass scales, and using recent data for the Standard Model observables. We find acceptable fits for normal neutrino mass ordering only and with neutrino mass generated by either type-I seesaw only or a combination of types I and II seesaw in which type-I seesaw is dominant. Furthermore, we find predictions from the best fit regarding the small neutrino masses, the effective neutrinoless double beta decay mass, and the leptonic CP-violating phase. Finally, we show that the fits are rather insensitive to the chosen value of the unification scale.
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| 6. |
- Ohlsson, Tommy, Professor, 1973-, et al.
(författare)
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Flavor symmetries in the Yukawa sector of non-supersymmetric SO(10) : numerical fits using renormalization group running
- 2021
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Ingår i: Journal of High Energy Physics (JHEP). - : Springer Nature. - 1126-6708 .- 1029-8479. ; :9
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Tidskriftsartikel (refereegranskat)abstract
- We consider a class of SO(10) models with flavor symmetries in the Yukawa sector and investigate their viability by performing numerical fits to the fermion masses and mixing parameters. The fitting procedure involves a top-down approach in which we solve the renormalization group equations from the scale of grand unification down to the electroweak scale. This allows the intermediate scale right-handed neutrinos and scalar triplet, involved in the type I and II seesaw mechanisms, to be integrated out at their corresponding mass scales, leading to a correct renormalization group running. The result is that, of the 14 models considered, only two are able to fit the known data well. Both these two models correspond to Z(2) symmetries. In addition to being able to fit the fermion masses and mixing parameters, they provide predictions for the sum of light neutrino masses and the effective neutrinoless double beta decay mass parameter, which are both within current observational bounds.
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| 7. |
- Ohlsson, Tommy, Professor, 1973-, et al.
(författare)
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One-loop matching conditions in neutrino effective theory
- 2022
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Ingår i: Nuclear Physics B. - : Elsevier BV. - 0550-3213 .- 1873-1562. ; 978
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Tidskriftsartikel (refereegranskat)abstract
- We investigate matching conditions and threshold corrections between full and effective theories based on the type I seesaw mechanism. In general, using an intuitive Feynman diagrammatical approach, we compute the amplitudes before and after integrating out heavy right-handed neutrinos at the matching scale. In particular, we derive the one-loop matching conditions between the full and the effective theories. The matching conditions of the parameters are influenced by one-loop corrections to the corresponding vertices as well as wave function corrections for the Higgs and the lepton fields. Our results are comparable to earlier results based on a functional approach.
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| 8. |
- Ohlsson, Tommy, Professor, 1973-, et al.
(författare)
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Realizing unification in two different SO(10) models with one intermediate breaking scale
- 2020
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Ingår i: European Physical Journal C. - : Springer Science and Business Media Deutschland GmbH. - 1434-6044 .- 1434-6052. ; 80:11
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Tidskriftsartikel (refereegranskat)abstract
- We derive the threshold corrections in SO (10) grand unified models with the intermediate symmetry being flipped SU(5)×U(1) or SU(3)×SU(2)×U(1)×U(1), with the masses of the scalar fields set by the survival hypothesis. These models do not achieve gauge coupling unification if the matching conditions do not take threshold corrections into account. We present results showing the required size of threshold corrections for any value of the intermediate and unification scales. In particular, our results demonstrate that both of these models are disfavored since they require large threshold corrections to allow for unification with a predicted proton lifetime above current experimental bounds.
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| 9. |
- Ohlsson, Tommy, 1973-, et al.
(författare)
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Running of fermion observables in non-supersymmetric SO(10) models
- 2018
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Ingår i: Journal of High Energy Physics (JHEP). - : SPRINGER. - 1126-6708 .- 1029-8479. ; :11
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the complete renormalization group running of fermion observables in two different realistic non-supersymmetric models based on the gauge group SO(10) with intermediate symmetry breaking for both normal and inverted neutrino mass orderings. Contrary to results of previous works, we find that the model with the more minimal Yukawa sector of the Lagrangian fails to reproduce the measured values of observables at the electroweak scale, whereas the model with the more extended Yukawa sector can do so if the neutrino masses have normal ordering. The difficulty in finding acceptable fits to measured data is a result of the added complexity from the effect of an intermediate symmetry breaking as well as tension in the value of the leptonic mixing angle theta 23
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| 10. |
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