|
1.
|
|
|
2.
|
How Accidental was Inflation?
/ Antoniadis, Ignatios (Chulalongkorn U. ; Paris, LPTHE) ; Ellis, John (King's Coll. London ; CERN) ; Ke, Wenqi (Minnesota U.) ; Nanopoulos, Dimitri V. (CERN ; Athens Academy ; Texas A-M) ; Olive, Keith A. (Minnesota U.)
Data on the cosmic microwave background (CMB) are discriminating between different models of inflation, disfavoring simple monomial potentials whilst being consistent with models whose predictions resemble those of the Starobinsky $R + R^2$ cosmological model. However, this model may suffer from theoretical problems, since it requires a large initial field value, threatening the validity of the effective field theory. [...]
arXiv:2504.12283; UMN-TH-4418/25; FTPI-MINN-25/03; KCL-PH-TH/2025-09; CERN-TH-2025-076.-
2025 - 31 p.
- Published in : JCAP 2508 (2025) 090
Fulltext: 2504.12283 - PDF; document - PDF;
|
|
|
3.
|
R$^{2}$-inflation derived from 4d strings, the role of the dilaton, and turning the Swampland into a mirage
/ Antoniadis, Ignatios (Chulalongkorn U. ; Paris, LPTHE) ; Nanopoulos, Dimitri V. (Athens Academy ; Texas A-M ; Athens U. ; HARC, Woodlands ; CERN) ; Olive, Keith A. (Minnesota U.)
Based on a previously derived superstring model possessing a cosmological sector that mimics Starobinsky inflation, we analyze several questions addressed in the recent literature: the generation of an effective $R^2$-term, the stability of the sgoldstino , the modular symmetry of the inflaton potential and the large distance swampland conjecture. We first show that the presence of the string dilaton stabilizes the sgoldstino direction in the supersymmetric case and no modification of the Kähler potential is needed. [...]
arXiv:2410.16541; UMN--TH--4402/24; FTPI--MINN--24/22; CERN-TH-2024-175.-
2025-06-17 - 24 p.
- Published in : JHEP 2506 (2025) 155
Fulltext: 2410.16541 - PDF; document - PDF;
|
|
|
4.
|
Non-universal SUSY models, $g_\mu -2$, $m_H$ and dark matter
/ Ellis, John (King's Coll. London ; CERN) ; Olive, Keith A. (Minnesota U.) ; Spanos, Vassilis C. (Minnesota U. ; Athens U.)
We study the anomalous magnetic moment of the muon, $g_\mu - 2 \equiv 2 a_\mu$, in the context of supersymmetric models beyond the CMSSM, where the unification of either the gaugino masses $M_{1,2,3}$ or sfermion and Higgs masses is relaxed, taking into account the measured mass of the Higgs boson, $m_H$, the cosmological dark matter density and the direct detection rate. We find that the model with non-unified gaugino masses can make a contribution $\Delta a_\mu\sim 20 \times 10^{-10}$ to the anomalous magnetic moment of the muon, for example if $M_{1,2} \sim 600$ GeV and $M_3\sim 8$ TeV. [...]
arXiv:2407.08679; KCL-PH-TH/2024-41; CERN-TH-2024-109; UMN-TH-4325/24; FTPI-MINN-24/16.-
2024-10-28 - 22 p.
- Published in : Eur. Phys. J. C 84 (2024) 1121
Fulltext: 2407.08679 - PDF; document - PDF;
|
|
|
5.
|
Electroweak Loop Contributions to the Direct Detection of Wino Dark Matter
/ Ellis, John (King's Coll. London ; CERN) ; Nagata, Natsumi (Tokyo U.) ; Olive, Keith A. (Minnesota U.) ; Zheng, Jiaming (Shanghai Jiaotong U., INPAC)
Electroweak loop corrections to the matrix elements for the spin-independent scattering of cold dark matter particles on nuclei are generally small, typically below the uncertainty in the local density of cold dark matter. However, as shown in this paper, there are instances in which the electroweak loop corrections are relatively large, and change significantly the spin-independent dark matter scattering rate. [...]
arXiv:2305.13837; KCL-PH-TH/2023-27; CERN-PH-TH-2023-083; FTPI-MINN-23/08; UMN-TH-4214/23.-
2024-01-04 - 27 p.
- Published in : Eur. Phys. J. C 84 (2024) 4
Fulltext: 2305.13837 - PDF; document - PDF;
|
|
|
6.
|
The CMSSM Survives Planck, the LHC, LUX-ZEPLIN, Fermi-LAT, H.E.S.S. and IceCube
/ Ellis, John (King's Coll. London ; CERN ; NICPB, Tallinn) ; Olive, Keith A. (Minnesota U.) ; Spanos, Vassilis C. (Athens Natl. Capodistrian U.) ; Stamou, Ioanna D. (Brussels U.)
We revisit the viability of the CMSSM, searching for regions of parameter space that yield a neutralino dark matter density compatible with Planck measurements, as well as LHC constraints including sparticle searches and the mass of the Higgs boson, recent direct limits on spin-independent and -dependent dark matter scattering from the LUX-ZEPLIN (LZ) experiment, the indirect constraints from Fermi-LAT and H.E.S.S. on dark matter annihilations to photons in dwarf spheroidal galaxies and the Galactic Centre, and the IceCube limits on muons from annihilations to neutrinos in the Sun. [...]
arXiv:2210.16337; KCL-PH-TH/2022-52; CERN-TH-2022-172; UMN-TH-4204/22; FTPI-MINN-22/29.-
2023-03-23 - 41 p.
- Published in : Eur. Phys. J. C 83 (2023) 246
Fulltext: document - PDF; 2210.16337 - PDF;
|
|
|
7.
|
Inflationary Gravitational Leptogenesis
/ Co, Raymond T. (Minnesota U., Theor. Phys. Inst.) ; Mambrini, Yann (IJCLab, Orsay ; CERN) ; Olive, Keith A. (Minnesota U., Theor. Phys. Inst.)
We consider the generation of the baryon asymmetry in models with right-handed neutrinos produced through gravitational scattering of the inflaton during reheating. The right-handed neutrinos later decay and generate a lepton asymmetry, which is partially converted to a baryon asymmetry by Standard Model sphaleron processes. [...]
arXiv:2205.01689; CERN-TH-2022-071; UMN-TH-4121/22; FTPI-MINN-22/12.-
2022-10-01 - 6 p.
- Published in : Phys. Rev. D 106 (2022) 075006
Fulltext: 2205.01689 - PDF; Publication - PDF;
|
|
|
8.
|
Gravitational portals with nonminimal couplings
/ Clery, Simon (IJCLab, Orsay) ; Mambrini, Yann (IJCLab, Orsay ; CERN) ; Olive, Keith A. (Minnesota U., Theor. Phys. Inst.) ; Shkerin, Andrey (Minnesota U., Theor. Phys. Inst.) ; Verner, Sarunas (Minnesota U., Theor. Phys. Inst.)
We consider the effects of non-minimal couplings to curvature of the form $\xi_S S^2 R$, for three types of scalars: the Higgs boson, the inflaton, and a scalar dark matter candidate. We compute the abundance of dark matter produced by these non-minimal couplings to gravity and compare to similar results with minimal couplings. [...]
arXiv:2203.02004; UMN--TH--4116/22; FTPI--MINN--22/07; CERN-TH-2022-025.-
2022-05-01 - 14 p.
- Published in : Phys. Rev. D 105 (2022) 095042
Fulltext: PhysRevD.105.095042 - PDF; 2203.02004 - PDF;
|
|
|
9.
|
Gravitational portals in the early Universe
/ Clery, Simon (IJCLab, Orsay) ; Mambrini, Yann (IJCLab, Orsay ; CERN) ; Olive, Keith A. (Minnesota U., Theor. Phys. Inst.) ; Verner, Sarunas (Minnesota U., Theor. Phys. Inst.)
We consider the production of matter and radiation during reheating after inflation, restricting our attention solely to gravitational interactions. Processes considered are the exchange of a graviton, $h_{\mu \nu}$, involved in the scattering of the inflaton or particles in the newly created radiation bath. [...]
arXiv:2112.15214; UMN-TH-4110/22; FTPI-MINN-22/02; CERN-TH-2021-222.-
2022-04-01 - 15 p.
- Published in : Phys. Rev. D 105 (2022) 075005
Fulltext: PDF;
|
|
|
10.
|
BICEP/Keck Constraints on Attractor Models of Inflation and Reheating
/ Ellis, John (King's Coll. London ; CERN ; NICPB, Tallinn) ; Garcia, Marcos A.G. (Mexico U.) ; Nanopoulos, Dimitri V. (Texas A-M ; HARC, Woodlands ; Athens Academy) ; Olive, Keith A. (Minnesota U., Theor. Phys. Inst.) ; Verner, Sarunas (Minnesota U., Theor. Phys. Inst.)
Recent BICEP/Keck data on the cosmic microwave background, in combination with previous WMAP and Planck data, impose strong new constraints on the tilt in the scalar perturbation spectrum, $n_s$, as well as the tensor-to-scalar ratio, $r$. These constrain the number of e-folds of inflation, $N_*$, the magnitude of the inflaton coupling to matter, $y$, and the reheating temperature, $T_{\rm reh}$, which we evaluate in attractor models of inflation as formulated in no-scale supergravity. [...]
arXiv:2112.04466; KCL-PH-TH/2021-90; CERN-TH-2021-199; ACT-06-21; MI-HET-769,
UMN-TH-4107/21; FTPI-MINN-21/26.-
2022-02-03 - 9 p.
- Published in : Phys. Rev. D 105 (2022) 043504
Fulltext: 2112.04466 - PDF; PhysRevD.105.043504 - PDF;
|
|
email alert
or subscribe to the 
RSS feed.