Supergravity provides the natural supersymmetric framework for early universe cosmology. A broad class of inflationary models in no-scale supergravity yields tree-level predictions for cosmic microwave background (CMB) observables that closely resemble those of the Starobinsky $\textit{R}$ + $\textit{R}$ model. Using results from global supersymmetry and supergravity, we analyze radiative corrections in models with canonical and non-canonical kinetic terms, focusing particularly on Starobinsky-like no-scale supergravity models. We derive conditions on the superpotential that keep the gravitino mass finite during inflation and ensure that loop-induced corrections to the Kähler potential remain either finite or subdominant relative to the tree-level potential. We show that in some models, most notably the original no-scale supergravity model with a Wess-Zumino superpotential, radiative corrections grow at large inflaton field values and can dominate the inflationary dynamics, rendering unreliable the model predictions for CMB data. However, we identify a class of no-scale Starobinsky-like models, including the Cecotti model, in which radiative corrections remain very small for inflaton field values ≲ 8 (in Planck units), preserving the agreement of the tree-level predictions with Planck CMB data.

United Kingdom

Switzerland

John Ellis

United States

Tony Gherghetta

Japan

Kunio Kaneta

Wenqi Ke

Keith Olive

Radiative corrections in supergravity models of inflation

The recently proposed swampland cobordism conjecture predicts the existence of new nonsupersymmetric objects which supplement the spectrum of low-energy gravitational effective field theories. In this paper, we study a subset of these defects related to the Gliozzi-Scherk-Olive projection on the string worldsheet. These include the predicted domain wall between type IIA and IIB superstring theories and the newly discovered R7-brane. We study these defects in two different ways: via long-string probes and target-space effective field theory. We find that the R7-brane can be identified with a collapsed cylindrical configuration of the IIA/IIB wall, and further, that the R7-brane is stable, in contrast to previous expectations. Moreover, we argue that BPS D-branes pulled across the IIA/IIB wall become non-BPS D-branes, which we identify with fluxbrane configurations. We show that the non-BPS D-branes of either type II theory are charged under a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi mathvariant="double-struck">Z</mi><mn>2</mn></msub></math> remnant of the Ramond-Ramond potentials of the other, which we identify with the mod 2 reduction of the Ramond-Ramond fluxes. Similar considerations provide a complementary perspective on the heterotic <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="fraktur">so</mi><mo stretchy="false">(</mo><mn>32</mn><mo stretchy="false">)</mo></math> S-duals of known non-BPS 7- and 8-branes in type I string theory.

Jonathan J. Heckman

Jacob McNamara

France

Julio Parra-Martinez

CERN

Ethan Torres

Gliozzi-Scherk-Olive defects: IIA/IIB walls and the surprisingly stable R7-brane

In many models of inflation, reheating is realized through a coupling between the inflaton and the Higgs boson. Often, the mass of the inflaton is of order <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mn>10</mn><mn>13</mn></msup><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math> determined by the amplitude of the scalar fluctuation spectrum. However, in models where the inflaton potential is of the form <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>V</mi><mo>∼</mo><msup><mi>ϕ</mi><mi>k</mi></msup></math> about its minimum, the inflaton is massless for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>k</mi><mo>≥</mo><mn>4</mn></math> unless a bare mass term, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mfrac><mn>1</mn><mn>2</mn></mfrac><msubsup><mi>m</mi><mi>ϕ</mi><mn>2</mn></msubsup><msup><mi>ϕ</mi><mn>2</mn></msup></math>, is present. In this case, the inflaton mass may be of order the electroweak scale and may be subject to existing collider constraints. In particular, we investigate the constraints on the inflaton mass and reheating temperature <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>T</mi><mrow><mi>rh</mi></mrow></msub></math> arising from the decay of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ϕ</mi></math> into <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">H</mi></math> through an interaction term <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>μ</mi><mi>ϕ</mi><mo stretchy="false">|</mo><mi mathvariant="script">H</mi><msup><mo stretchy="false">|</mo><mn>2</mn></msup></math>. We perform a renormalization group analysis to determine the relative values of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>μ</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>ϕ</mi></msub></math> such that the Higgs potential remains stable (and perturbative) at high energy. Taking into account the running of the Higgs quartic self-coupling and the experimental constraints from the LHC via the higgstools public code, we find that <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>3.4</mn><mo>×</mo><msup><mn>10</mn><mn>6</mn></msup><mtext> </mtext><mtext> </mtext><mrow><mi>GeV</mi></mrow><mo>≲</mo><msub><mi>T</mi><mrow><mi>rh</mi></mrow></msub><mo>≲</mo><mn>3.9</mn><mo>×</mo><msup><mn>10</mn><mn>12</mn></msup><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math> with a corresponding constraint on the inflaton bare mass <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>260</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi><mo>≲</mo><msub><mi>m</mi><mi>ϕ</mi></msub><mo>≲</mo><mn>3.8</mn><mo>×</mo><msup><mn>10</mn><mn>10</mn></msup><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math>. The dependencies between <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>T</mi><mrow><mi>rh</mi></mrow></msub></math> and the inflaton bare mass <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>ϕ</mi></msub></math> as well as between <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>μ</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>ϕ</mi></msub></math> are provided.

Yann Cado

Mathieu Gross

Yann Mambrini

Phenomenological constraints on Higgs reheating

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 $\textit{R}$ -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. This is a generic property of a large class of Starobinsky type models within the framework of no-scale supergravity. We then present an explicit example of a string derived inflaton potential where the large values of the inflaton field during inflation imply a decompactification of two extra dimensions, while the scale of inflation is generated by higher order $\textit{α}$ -corrections via expectation values that cancel the D-term of an anomalous U(1) symmetry and break the modular symmetry of the scalar potential. As a result, the scale of inflation is much lower than the compactification scale which at the end of inflation is fixed at the free-fermionic self-dual point at an (approximate) supersymmetric minimum.

Thailand

Ignatios Antoniadis

Greece

Dimitri Nanopoulos

We study the anomalous magnetic moment of the muon, $$g_\mu - 2 \equiv 2 a_\mu $$ <math> <mrow> <msub> <mi>g</mi> <mi>μ</mi> </msub> <mo>-</mo> <mn>2</mn> <mo>≡</mo> <mn>2</mn> <msub> <mi>a</mi> <mi>μ</mi> </msub> </mrow> </math> , in the context of supersymmetric models beyond the CMSSM, where the unification of either the gaugino masses $$M_{1,2,3}$$ <math> <msub> <mi>M</mi> <mrow> <mn>1</mn> <mo>,</mo> <mn>2</mn> <mo>,</mo> <mn>3</mn> </mrow> </msub> </math> or sfermion and Higgs masses is relaxed, taking into account the measured mass of the Higgs boson, $$m_H$$ <math> <msub> <mi>m</mi> <mi>H</mi> </msub> </math> , the cosmological dark matter density and the direct detection rate. We find that the model with non-unified gaugino masses can make a contribution $$\Delta a_\mu \sim 20 \times 10^{-10}$$ <math> <mrow> <mi>Δ</mi> <msub> <mi>a</mi> <mi>μ</mi> </msub> <mo>∼</mo> <mn>20</mn> <mo>×</mo> <msup> <mn>10</mn> <mrow> <mo>-</mo> <mn>10</mn> </mrow> </msup> </mrow> </math> to the anomalous magnetic moment of the muon, for example if $$M_{1,2} \sim 600\; \textrm{GeV}$$ <math> <mrow> <msub> <mi>M</mi> <mrow> <mn>1</mn> <mo>,</mo> <mn>2</mn> </mrow> </msub> <mo>∼</mo> <mn>600</mn> <mspace width="0.277778em"></mspace> <mtext>GeV</mtext> </mrow> </math> and $$M_3\sim 8 \; \textrm{TeV}$$ <math> <mrow> <msub> <mi>M</mi> <mn>3</mn> </msub> <mo>∼</mo> <mn>8</mn> <mspace width="0.277778em"></mspace> <mtext>TeV</mtext> </mrow> </math> . The model with non-universal sfermion and Higgs masses can provide even larger $$\Delta a_\mu \sim 24 \times 10^{-10}$$ <math> <mrow> <mi>Δ</mi> <msub> <mi>a</mi> <mi>μ</mi> </msub> <mo>∼</mo> <mn>24</mn> <mo>×</mo> <msup> <mn>10</mn> <mrow> <mo>-</mo> <mn>10</mn> </mrow> </msup> </mrow> </math> if the sfermion masses for the first and the second generations are $$ \sim 400 \; \textrm{GeV}$$ <math> <mrow> <mo>∼</mo> <mn>400</mn> <mspace width="0.277778em"></mspace> <mtext>GeV</mtext> </mrow> </math> and that of the third is $$ \sim 8 \; \textrm{TeV}$$ <math> <mrow> <mo>∼</mo> <mn>8</mn> <mspace width="0.277778em"></mspace> <mtext>TeV</mtext> </mrow> </math> . We discuss the prospects for collider searches for supersymmetric particles in specific benchmark scenarios illustrating these possibilities, focusing in particular on the prospects for detecting the lighter smuon and the lightest neutralino.

Vassilis Spanos

Non-universal SUSY models, $$g_\mu -2$$ <math> <mrow> <msub> <mi>g</mi> <mi>μ</mi> </msub> <mo>-</mo> <mn>2</mn> </mrow> </math> , $$m_H$$ <math> <msub> <mi>m</mi> <mi>H</mi> </msub> </math> and dark matter

We explore possible extensions of the Weak Gravity Conjecture (WGC) to scalar field theories. To avoid charged black hole remnants, the WGC requires the existence of a particle with a mass m ≤ gqM  P , with charge q and U(1) gauge coupling g, allowing the decay to shed the black hole charge. Although there is no obvious problem that arises in the absence of a U(1) charge, it has been postulated that gravity must remain the weakest force even when extended to scalar interactions. Quantifying this conjecture may be done by comparing scalar and gravitational amplitudes, or as we advocate here by comparing scattering cross sections. In theories with non-trivial field space geometries, by working out examples with perturbation theory around arbitrary field values and performing tadpole resummations, we argue that the conjecture must be applied only at extrema of the scalar potential (when expressed in locally canonical coordinates). We consider several toy models in the context of no-scale supergravity and also consider examples of inflationary models.

Emilian Dudas

Sarunas Verner

Testing the scalar weak gravity conjecture in no-scale supergravity

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. An important example occurs when the dark matter particle is a wino, e.g., in anomaly-mediated supersymmetry breaking (AMSB) and pure gravity mediation (PGM) models. We find that the one-loop electroweak corrections to the spin-independent wino LSP scattering cross section generally interfere constructively with the tree-level contribution for AMSB models with negative Higgsino mixing, $$\mu &lt; 0$$ <math> <mrow> <mi>μ</mi> <mo>&lt;</mo> <mn>0</mn> </mrow> </math> , and in PGM-like models for both signs of $$\mu $$ <math> <mi>μ</mi> </math> , lifting the cross section out of the neutrino fog and into a range that is potentially detectable in the next generation of direct searches for cold dark matter scattering.

Natsumi Nagata

China

Jiaming Zheng

Electroweak loop contributions to the direct detection of wino dark matter

We revisit the calculation of the electron, neutron, and proton electric dipole moments (EDMs) in the constrained minimal supersymmetric standard model (CMSSM). The relatively large mass of the Higgs boson, m  H  ≃ 125 GeV coupled with the (as yet) lack of discovery of any supersymmetric particle at the LHC, has pushed the supersymmetry breaking scale to several TeV or higher. Though one might expect this decoupling to have relaxed completely any bounds on the two CP violating phases in the CMSSM (θ  μ  and θ  A ), the impressive experimental improvements in the limits on the EDMs (particularly the electron EDM) still allow us to set constraints of order (0.01−0.1)π on θ  A  and (0.001−0.1)π on θ  μ . We also discuss the impact of future improvements in the experimental limits on supersymmetric models.

Maxim Pospelov

South Korea

Liliana Velasco-Sevilla

Quantifying limits on CP violating phases from EDMs in supersymmetry

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. For representative values of $$\tan \beta $$ <math> <mrow> <mo>tan</mo> <mi>β</mi> </mrow> </math> and $$A_0$$ <math> <msub> <mi>A</mi> <mn>0</mn> </msub> </math> we map in detail the Planck-compatible strips in CMSSM parameter planes, which exhibit multiple distinctive features for large $$\tan \beta $$ <math> <mrow> <mo>tan</mo> <mi>β</mi> </mrow> </math> , $$A_0 = 0$$ <math> <mrow> <msub> <mi>A</mi> <mn>0</mn> </msub> <mo>=</mo> <mn>0</mn> </mrow> </math> and $$\mu &gt; 0$$ <math> <mrow> <mi>μ</mi> <mo>&gt;</mo> <mn>0</mn> </mrow> </math> , and identify portions of the strips that survive all the phenomenological constraints. We find that the most powerful constraint is that from $$m_h$$ <math> <msub> <mi>m</mi> <mi>h</mi> </msub> </math> , followed by the LZ limit on spin-independent scattering, whereas sparticle searches at the LHC and indirect dark matter searches are less restrictive. Most of the surviving CMSSM parameter space features a Higgsino-like dark matter particle with a mass $$\sim 1000{-}1100$$ <math> <mrow> <mo>∼</mo> <mn>1000</mn> <mo>-</mo> <mn>1100</mn> </mrow> </math> GeV, which could best be probed with future direct searches for dark matter scattering.

Estonia

Belgium

Ioanna Stamou

The CMSSM survives Planck, the LHC, LUX-ZEPLIN, Fermi-LAT, H.E.S.S. and IceCube

We show that a minimal scenario, utilizing only the graviton as an intermediate messenger between the inflaton, the dark sector and the Standard Model (SM), is able to generate simultaneously the observed relic density of dark matter (DM), the baryon asymmetry through leptogenesis, as well as a sufficiently hot thermal bath after inflation. We assume an inflaton potential of the form V(ϕ) ∝ ϕ k about the minimum at the end of inflation. The possibility of reheating via minimal gravitational interactions has been excluded by constraints on dark radiation for excessive gravitational waves produced from inflation. We thus extend the minimal model in several ways: i) we consider non-minimal gravitational couplings — this points to the parameter range of DM masses <math> <msub> <mi>M</mi> <msub> <mi>N</mi> <mn>1</mn> </msub> </msub> </math> $$ {M}_{N_1} $$ ≃ 2–10 PeV, and right-handed neutrino masses <math> <msub> <mi>M</mi> <msub> <mi>N</mi> <mn>2</mn> </msub> </msub> </math> $$ {M}_{N_2} $$ ≃ (5–20) × 1011 GeV, and T RH ≲ 3 × 105 GeV (for k ≤ 20); ii) we propose an explanation for the PeV excess observed by IceCube when the DM has a direct but small Yukawa coupling to the SM; and iii) we also propose a novel scenario, where the gravitational production of DM is a two-step process, first through the production of two scalars, which then decay to fermionic DM final states. In this case, the absence of a helicity suppression enhances the production of DM and baryon asymmetry, and allows a great range for the parameters including a dark matter mass below an MeV where dark matter warmness can be observable by cosmic 21-cm lines, even when gravitational interactions are responsible for reheating. We also show that detectable primordial gravitational wave signals provide the opportunity to probe this scenario for T RH ≲ 5 × 106 GeV in future experiments, such as BBO, DECIGO, CE and ET.