scholarly journals Reheating after inflation by supersymmetry breaking

2021 ◽  
Vol 81 (12) ◽  
Author(s):  
Yermek Aldabergenov ◽  
Ignatios Antoniadis ◽  
Auttakit Chatrabhuti ◽  
Hiroshi Isono
Keyword(s):  
Dark Matter ◽  
Mass Spectrum ◽  
Standard Model ◽  
Supersymmetry Breaking ◽  
The Other ◽  
Large Field ◽  
Small Field ◽  
Parameter Choice ◽  
Decay Modes ◽  
R Symmetry

AbstractWe study reheating after the end of inflation in models where the inflaton is the superpartner of goldstino and is charged under a gauged U(1) R-symmetry. We consider two classes of models – one is small field characterized by an almost flat Kähler space, and the other large field characterized by a hyperbolic Kähler space SU(1, 1)/U(1), while in both cases the inflaton superpotential is linear due to the R-symmetry. The inflationary observables of our models fit within 2$$\sigma $$ σ CMB values. Upon coupling the inflaton sector to the (supersymmetric) Standard Model, we compute the MSSM parameters, mass spectrum, and decay modes of the inflaton, with the resulting reheating temperature around $$10^8$$ 10 8 GeV. We also find that both models can accommodate superheavy LSP dark matter, depending on the parameter choice.

scholarly journals Collider signatures of coannihilating dark matter in light of the B-physics anomalies

2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
Michael J. Baker ◽  
Darius A. Faroughy ◽  
Sokratis Trifinopoulos
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Bound States ◽  
B Physics ◽  
Search Strategy ◽  
Dark Matter Candidate ◽  
Final States ◽  
Dark Sector ◽  
Decay Modes ◽  
The Standard Model

Abstract Motivated by UV explanations of the B-physics anomalies, we study a dark sector containing a Majorana dark matter candidate and a coloured coannihilation partner, connected to the Standard Model predominantly via a U1 vector leptoquark. A TeV scale U1 leptoquark, which couples mostly to third generation fermions, is the only successful single-mediator description of the B-physics anomalies. After calculating the dark matter relic surface, we focus on the most promising experimental avenue: LHC searches for the coloured coannihilation partner. We find that the coloured partner hadronizes and forms meson-like bound states leading to resonant signatures at colliders reminiscent of the quarkonia decay modes in the Standard Model. By recasting existing dilepton and monojet searches we exclude coannihilation partner masses less than 280 GeV and 400 GeV, respectively. Since other existing collider searches do not significantly probe the parameter space, we propose a new dedicated search strategy for pair production of the coloured partner decaying into bbττ final states and dark matter particles. This search is expected to probe the model up to dark matter masses around 600 GeV with current luminosity.

scholarly journals Higgs portal to dark matter and $$B\rightarrow K^{(*)}$$ decays

2020 ◽  
Vol 80 (7) ◽  
Author(s):  
Aliaksei Kachanovich ◽  
Ulrich Nierste ◽  
Ivan Nišandžić
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Decay Rates ◽  
Dark Sector ◽  
Mixing Angle ◽  
Decay Modes ◽  
Simultaneous Study ◽  
Belle Ii ◽  
Displaced Vertex ◽  
Higgs Portal

Abstract We consider a Higgs portal model in which the 125-GeV Higgs boson mixes with a light singlet mediator $$h_2$$h2 coupling to particles of a Dark Sector and study potential $$b\rightarrow s h_2$$b→sh2 decays in the Belle II experiment. Multiplying the gauge-dependent off-shell Standard-Model b-s-Higgs vertex with the sine of the Higgs mixing angle does not give the correct b-s-$$h_2$$h2 vertex. We clarify this issue by calculating the b-s-$$h_2$$h2 vertex in an arbitrary $$R_\xi $$Rξ gauge and demonstrate how the $$\xi $$ξ dependence cancels from physical decay rates involving an on-shell or off-shell $$h_2$$h2. Then we revisit the $$b\rightarrow s h_2$$b→sh2 phenomenology and point out that a simultaneous study of $$B\rightarrow K^* h_2$$B→K∗h2 and $$B\rightarrow K h_2$$B→Kh2 helps to discriminate between the Higgs portal and alternative models of the Dark Sector. We further advocate for the use of the $$h_2$$h2 lifetime information contained in displaced-vertex data with $$h_2$$h2 decaying back to Standard-Model particles to better constrain the $$h_2$$h2 mass or to reveal additional $$h_2$$h2 decay modes into long-lived particles.

scholarly journals Flipped $$\mathbf {g_\mu - 2}$$

2021 ◽  
Vol 81 (12) ◽  
Author(s):  
John Ellis ◽  
Jason L. Evans ◽  
Natsumi Nagata ◽  
Dimitri V. Nanopoulos ◽  
Keith A. Olive
Keyword(s):  
Standard Model ◽  
Supersymmetry Breaking ◽  
Model Calculation ◽  
Experimental Measurement ◽  
The Other ◽  
Gaugino Mass ◽  
The Standard Model ◽  
Soft Supersymmetry Breaking ◽  
The Right

AbstractWe analyze the possible magnitude of the supersymmetric contribution to $$g_\mu - 2$$ g μ - 2 in a flipped SU(5) GUT model. Unlike other GUT models which are severely constrained by universality relations, in flipped SU(5) the U(1) gaugino mass and the soft supersymmetry-breaking masses of right-handed sleptons are unrelated to the other gaugino, slepton and squark masses. Consequently, the lightest neutralino and the right-handed smuon may be light enough to mitigate the discrepancy between the experimental measurement of $$g_\mu - 2$$ g μ - 2 and the Standard Model calculation, in which case they may be detectable at the LHC and/or a 250 GeV $$e^+ e^-$$ e + e - collider, whereas the other gauginos and sfermions are heavy enough to escape detection at the LHC.

scholarly journals Nearly Supersymmetric Dark Atoms

2011 ◽  
Vol 2011 ◽  
pp. 1-34 ◽  
Author(s):  
Siavosh R. Behbahani ◽  
Martin Jankowiak ◽  
Tomas Rube ◽  
Jay G. Wacker
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Supersymmetry Breaking ◽  
Bound States ◽  
Dark Sector ◽  
Missing Mass ◽  
The Standard Model ◽  
The Universe

Theories of dark matter that support bound states are an intriguing possibility for the identity of the missing mass of the Universe. This article proposes a class of models of supersymmetric composite dark matter where the interactions with the Standard Model communicate supersymmetry breaking to the dark sector. In these models, supersymmetry breaking can be treated as a perturbation on the spectrum of bound states. Using a general formalism, the spectrum with leading supersymmetry effects is computed without specifying the details of the binding dynamics. The interactions of the composite states with the Standard Model are computed, and several benchmark models are described. General features of nonrelativistic supersymmetric bound states are emphasized.

scholarly journals Inflation from Supersymmetry Breaking

Universe ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. 30 ◽  
Author(s):  
Ignatios Antoniadis
Keyword(s):  
Supersymmetry Breaking ◽  
Vacuum Energy ◽  
Scalar Potential ◽  
Small Field ◽  
Slow Roll ◽  
Cosmological Observations ◽  
Interesting Class ◽  
The Universe ◽  
R Symmetry

I discuss the possibility that inflation is driven by supersymmetry breaking, with the superpartner of the goldstino (sgoldstino) playing the role of the inflaton. Imposing an R-symmetry to satisfy the slow-roll conditions, avoiding the so-called η -problem, leads to an interesting class of small field inflation models, characterised by an inflationary plateau around the maximum of scalar potential near the origin, where R-symmetry is restored with the inflaton rolling down to a minimum, describing the present phase of the Universe. Inflation can be driven by either an F- or a D-term, while the minimum has a positive tuneable vacuum energy. The models agree with cosmological observations and, in the simplest case, predict a rather small tensor-to-scalar ratio of primordial perturbations. This talk is an extended version of an earlier review (Antoniadis, 2018).

scholarly journals Doublet–singlet model and unitarity

2016 ◽  
Vol 31 (01) ◽  
pp. 1650013 ◽  
Author(s):  
G. Cynolter ◽  
J. Kovács ◽  
E. Lendvai
Keyword(s):  
Dark Matter ◽  
Mass Spectrum ◽  
Scattering Amplitudes ◽  
Standard Model ◽  
Dark Matter Candidate ◽  
Particle Scattering ◽  
Gauge Bosons ◽  
Yukawa Couplings ◽  
The Standard Model ◽  
Blind Spots

We study the renormalizable singlet–doublet fermionic extension of the Standard Model (SM). In this model, the new vector-like fermions couple to the gauge bosons and to the Higgs via new Yukawa couplings that allow for nontrivial mixing in the new sector, providing a stable, neutral dark matter candidate. Approximate analytic formulae are given for the mass spectrum around the blind spots, where the dark matter candidate coupling to h or Z vanishes. We calculate the two particle scattering amplitudes in the model, impose the perturbative unitarity constraints and establish bounds on the Yukawa couplings.

Challenges in string and supersymmetric cosmology

2021 ◽  
pp. 2044030
Author(s):  
Ignatios Antoniadis ◽  
Auttakit Chatrabhuti
Keyword(s):  
Supersymmetry Breaking ◽  
Vacuum Energy ◽  
Scalar Potential ◽  
Small Field ◽  
Slow Roll ◽  
Cosmological Observations ◽  
Interesting Class ◽  
The Universe ◽  
R Symmetry

We discuss the possibility that inflation is driven by supersymmetry breaking with the superpartner of the goldstino (sgoldstino) playing the role of the inflaton. Imposing an R-symmetry allows to satisfy easily the slow-roll conditions, avoiding the so-called [Formula: see text]-problem, and leads to an interesting class of small field inflation models, characterized by an inflationary plateau around the maximum of the scalar potential near the origin, where R-symmetry is restored with the inflaton rolling down to a minimum describing the present phase of the Universe. Inflation can be driven by either an [Formula: see text]- or a [Formula: see text]-term, while the minimum has a positive tuneable vacuum energy. The models agree with cosmological observations and in the simplest case predict a rather small tensor-to-scalar ratio of primordial perturbations.

scholarly journals New Physics Beryond the SM at BESIII

2019 ◽  
Vol 212 ◽  
pp. 06004
Author(s):  
Minggang Zhao
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
New Physics ◽  
Dark Sector ◽  
Decay Modes ◽  
The Standard Model ◽  
The Masses

Numerous astrophysical observations strongly suggest the existence of Dark Matter, which provides a hint of dark sector physics. There could exist many dark candidates predicted by theories BSM, such as dark photons and invisible things, that communicate with the Standard Model sector. The masses and decay modes of these particles are expected to be accessible at the BESIII experiment which is the only currently running tau-charm factory with the largest threshold charm samples and some other unique datasets. We have recently performed searches of dark photons and invisible things in several decay modes. Besides, FCNC processes, BNV/LNV processes are also investigated. This talk will summarize the recent results at BESIII on these searches for new physics BSM.

scholarly journals SINGLET FERMION DARK MATTER AND ELECTROWEAK BARYOGENESIS WITH RADIATIVE NEUTRINO MASS

2008 ◽  
Vol 23 (12) ◽  
pp. 1813-1819 ◽  
Author(s):  
K. S. BABU ◽  
ERNEST MA
Keyword(s):  
Dark Matter ◽  
Scalar Field ◽  
Standard Model ◽  
Neutrino Mass ◽  
The Other ◽  
Higgs Potential ◽  
Neutral Component ◽  
The Standard Model ◽  
Realistic Possibility ◽  
The Universe

The model of radiative neutrino mass with dark matter proposed by one of us is extended to include a real singlet scalar field. There are then two important new consequences. One is the realistic possibility of having the lightest neutral singlet fermion (instead of the lightest neutral component of the dark scalar doublet) as the dark matter of the universe. The other is a modification of the effective Higgs potential of the Standard Model, consistent with electroweak baryogenesis.

scholarly journals Scale hierarchies, supersymmetry and cosmology

2018 ◽  
Vol 33 (34) ◽  
pp. 1845003
Author(s):  
Ignatios Antoniadis
Keyword(s):  
Supersymmetry Breaking ◽  
General Class ◽  
Vacuum Energy ◽  
Scalar Potential ◽  
Small Field ◽  
Slow Roll ◽  
Cosmological Observations ◽  
R Symmetry

I discuss a general class of models where the inflation is driven by supersymmetry breaking with the superpartner of the goldstino (sgoldstino) playing the role of the inflaton. Imposing an R-symmetry allows to satisfy easily the slow-roll conditions, avoiding the so-called [Formula: see text]-problem, and leads to two different classes of small field inflation models; they are characterized by an inflationary plateau around the maximum of the scalar potential, where R-symmetry is either restored or spontaneously broken, with the inflaton rolling down to a minimum describing the present phase of our universe. Inflation can be driven by either an F- or a D-term, while the minimum has a positive tuneable vacuum energy. The models agree with cosmological observations and in the simplest case predict a tensor-to-scalar ratio of primordial perturbations [Formula: see text] and an inflation scale [Formula: see text].

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