Supersymmetry Breaking Models Research Articles

HL-LHC sensitivity to higgsinos from natural SUSY with gravitino LSP

In the realm of natural supersymmetric models, higgsinos are typically the lightest electroweakinos. In gauge-mediated supersymmetry breaking models, the lightest higgsino-dominated particles decay into a Z-boson or a Higgs boson (h), along with an ultra-light gravitino (G~\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ ilde{G}$$\\end{document}) serving as the lightest supersymmetric particle (LSP). This scenario suggests a significant non-resonant hh production. Basing on the recent global fitting results of the G~\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ ilde{G}$$\\end{document}-EWMSSM (MSSM with light electroweakinos and an eV-scale gravitino as the LSP) performed by the GAMBIT collaboration, which support a higgsino-dominated electroweakino as light as 140 GeV, we develop two simplified models to evaluate their detection potential at the high-luminosity LHC (HL-LHC) with s=14TeV\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\sqrt{s} = 14~\ extrm{TeV}$$\\end{document} and an integrated luminosity of 3000fb-1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$3000~\ extrm{fb}^{-1}$$\\end{document}. The first model examines the processes where heavier higgsino-dominated states decay into soft W/Z bosons, while the second focuses on direct decays of all three higgsino-dominated electroweakinos into W/Z/h plus a G~\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ ilde{G}$$\\end{document}. Our study, incorporating both models and their distinct decay channels, utilizes detailed Monte Carlo simulations for signals and standard model backgrounds. We find that the HL-LHC can probe higgsinos up to 575 GeV, potentially discovering or excluding the natural SUSY scenario in the context of a gravitino LSP. Further, we reinterpret this discovery potential using the GAMBIT global fit samples, and find that the entire parameter space of |μ|≤500GeV\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$|\\mu | \\le 500~\ extrm{GeV}$$\\end{document} with an electroweak fine-tuning measure (ΔEW\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Delta _{\ extrm{EW}}$$\\end{document}) under 100 in G~\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ ilde{G}$$\\end{document}-EWMSSM is accessible at the HL-LHC.

Electroweak loop contributions to the direct detection of wino dark matter

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 < 0, and in PGM-like models for both signs of mu , 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.

Spontaneous supersymmetry breaking in inhomogeneous supersymmetric field theories and BPS vacua

We study spontaneous supersymmetry breaking in inhomogeneous extensions of N\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\mathcal{N} $$\\end{document} = 1 supersymmetric field theory models in 4-dimensions. The N\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\mathcal{N} $$\\end{document} = 1 Abelian Higgs model with the inhomogeneous mass parameter and the FI coefficient that are dependent on spatial coordinates, as well as the O’Raifeartaigh model with all its parameters being dependent on spatial coordinates, are studied in detail. In the presence of inhomogeneous parameters, half supersymmetry can be preserved by adding appropriate inhomogeneous deformations to the original Lagrangians. The inhomogeneous deformations often break the R-symmetry explicitly. In cases where the inhomogeneous deformations do not break the R-symmetry explicitly, we demonstrate that spontaneous breaking of the R-symmetry is infeasible. We argue that those models can not be spontaneous supersymmetry breaking models, according to the Nelson-Seiberg argument. We comment on this issue in the context of a generic N\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\mathcal{N} $$\\end{document} = 1 supersymmetric model as well.

SuSpect3: A C++ code for the supersymmetric and Higgs particle spectrum of the MSSM

We present the program SuSpect3 that calculates the masses and couplings of the Higgs and supersymmetric particles predicted by the Minimal Supersymmetric Standard Model (MSSM). The model is implemented in both its non-constrained version, the MSSM, and its constrained versions, such as the minimal supergravity and the gauge or anomaly mediated supersymmetry breaking models, in which the soft supersymmetry–breaking parameters obey certain universal boundary conditions at the high energy scale. The low energy parameters are then obtained using renormalization group equations and electroweak symmetry breaking, and all the dominant radiative corrections have been consistently implemented. SuSpect3 is a major rewrite, in C++ object oriented programming, of the FORTRAN code SuSpect. It includes all the features of the earlier code in an improved and updated manner, and involves new options such as compressed SUSY scenarios, an MSSM-inflation model and the possibility of using the observed Higgs mass as an input. The main features and the use of the program are explained. Program summaryProgram Title:SuSpect3CPC Library link to program files:https://doi.org/10.17632/55jv4kdrm8.1Developer's repository link:http://suspect.in2p3.frLicensing provisions: GPLv3Programming language:C++, compatible C++98, C++11, C++14, C++17Nature of problem: Supersymmetric models such as the MSSM, mSUGRA, GMSB, AMSB and others have specific parameter sets and boundary conditions. SuSpect3 translates the parameter sets of the models into predictions of the Higgs and supersymmetric particles masses. The mixing matrices of the physical states as well as the mixing angles are calculated in addition to the scale dependent parameters.Solution method: The spectrum of the Higgs and supersymmetric particles depends on the model, its supersymmetric parameter set and the Standard Model parameters. The evolution of the parameters as function of the energy scale is calculated by solving numerically the Renormalization Group Equations. Model dependent boundary conditions are applied at the appropriate scale. Electroweak symmetry breaking is calculated iteratively at the electroweak scale. The application of radiative corrections translate the scale dependent particle masses into the physical pole masses.Additional comments including restrictions and unusual features: The parameters and physical masses are defined to be real. Warnings are issued if intermediate results are unphysical.Compiles with gcc-4.8.5 and later (checked with gcc-8.1.0).

PeV-scale leptogenesis, gravitational waves, and black holes from a SUSY-breaking phase transition

Supersymmetry is a highly motivated theoretical framework, whose scale of breaking may be at PeV energies, to explain null searches at the Large Hadron Collider. SUSY breaking through a first order phase transition may have occurred in the early universe, leading to potential gravitational wave signals. Constructing a realistic model for gauge-mediated supersymmetry breaking, we show that such a transition can also induce masses for heavy right-handed neutrinos and sneutrinos, whose CP-violating decays give leptogenesis at the PeV scale, and a novel mechanism of neutrino mass generation at one loop. For the same models we predict the possible gravity wave signals, and we study the possibility of production of primordial black holes during the phase transition.

Higgsino dark matter in pure gravity mediated supersymmetry

We consider the prospects for the direct detection of dark matter in pure gravity meditation (PGM) models of supersymmetry breaking. Minimal PGM models require only two parameters, the gravitino mass, $m_{3/2}$, which sets the UV mass for all scalar masses, and $\tan\beta$. Gaugino masses are generated through anomaly mediation. Typically the lightest supersymmetric state (the dark matter candidate) is a wino. Here, we consider a one-parameter extension of the minimal model by allowing the Higgs soft masses to deviate from universality. For simplicity, we take these to be equal and use the $\mu$-term as a surrogate. We also consider non-universal stop masses. When $|\mu| \sim 1$ TeV, the Higgsino is a viable dark matter candidate when the gravitino mass is of order $\sim 1$ PeV and $\tan\beta \simeq 2$. We calculate the spin-dependent and spin-independent cross sections for dark matter scattering on protons. For spin-independent scattering, existing experimental limits place constraints on the PGM parameter space. Much of the currently allowed parameter space lies above the irreducible neutrino background. Thus, future direct detection experiments will be able to probe much of the remaining PGM parameter space.

Gravitational waves in metastable supersymmetry breaking

If supersymmetry is broken in metastable vacua, it is not clear why we are now in there rather than supersymmetric vacua. Moreover, it is natural to expect that we were in supersymmetric vacua, which have higher symmetry than metastable vacua, in the early universe. In this paper, we reexamine and improve the previous analysis on the cosmological evolution of the vacuum structure in the ISS model of metastable supersymmetry breaking by taking into account constraints on the reheating temperature, which is needed to avoid the overproduction of gravitinos. It turns out that the desired phase transition from a supersymmetric vacuum to a metastable vacuum is allowed only in the light gravitino mass region $m_{3/2} < 4.7$ eV. This is achieved by either rolling down potential or tunneling processes depending on the reheating temperature. We show that when the tunneling processes are realized, abundant gravitational waves could be produced from collisions of runaway bubbles. The resulting gravitational waves are detectable with the future gravitational wave interferometers like LISA and DECIGO.

Flavored gauge-mediated supersymmetry breaking models with discrete non-Abelian symmetries

We investigate flavored gauge mediation models in which the Higgs and messenger doublets are embedded in multiplets of the discrete non-Abelian symmetry ${\mathcal{S}}_{3}$. In these theories, the ${\mathcal{S}}_{3}$ symmetry correlates the flavor structure of the quark and lepton Yukawa couplings with the structure of the messenger Yukawa couplings that contribute to the soft supersymmetry breaking mass parameters. We provide a systematic exploration of possible scenarios within this framework that can accommodate hierarchical quark and charged lepton masses, and examine the resulting phenomenological implications in each case. We find a heavier spectrum for the superpartner masses compared to flavored gauge mediation models controlled by Abelian symmetries, which can be directly traced back to the need in our scenarios for two vectorlike pairs of messenger fields for viable electroweak symmetry breaking.

Muon g \u2212 2 in gauge mediation without SUSY CP problem

We discuss gauge mediated supersymmetry breaking models which explain the observed muon anomalous magnetic moment and the Higgs boson mass simultaneously. The successful explanation requires the messenger sector which violates the relation motivated by the grand unification theory (GUT). The naive violation of the GUT relation, however, ends up with the CP problem. We propose a model in which the phases of the gaugino masses are aligned despite the violation of the GUT relation. We also consider a model which generates the μ-term and the additional Higgs soft masses squared without causing CP violation. As a result, we find a successful model which explains the muon anomalous magnetic moment and the Higgs boson mass. The model is also free from the CP, flavor-changing neutral current and the lepton flavor violation problems caused by the subdominant gravity mediation effects. The lightest supersymmetric particles are gravitino/goldstini and the next-to-lightest ones are the Wino/Higgsinos in the typical parameter space. We also study the LHC constraints.

Alpha -attractors from supersymmetry breaking

We construct new models of inflation and spontaneous supersymmetry breaking in de Sitter vacuum, with a single chiral superfield, where inflaton is the superpartner of the goldstino. Our approach is based on hyperbolic Kähler geometry, and a gauged (non-axionic) U(1)_R symmetry rotating the chiral scalar field by a phase. The U(1)_R gauge field combines with the angular component of the chiral scalar to form a massive vector, and single-field inflation is driven by the radial part of the scalar. We find that in a certain parameter range they can be approximated by simplest Starobinsky-like (E-model) alpha -attractors, thus predicting n_s and r within 1sigma CMB constraints. Supersymmetry (and R-symmetry) is broken at a high scale with the gravitino mass m_{3/2} > rsim 10^{14} GeV, and the fermionic sector also includes a heavy spin-1/2 field. In all the considered cases the inflaton is the lightest field of the model.

Phenomenology and cosmology of no-scale attractor models of inflation

We have recently proposed attractor models for modulus fixing, inflation, supersymmetry breaking and dark energy based on no-scale supergravity. In this paper we develop phenomenological and cosmological aspects of these no-scale attractor models that underpin their physical applications. We consider models in which inflation is driven by a modulus field (T-type) with supersymmetry broken by a Polonyi field, or a matter field (ϕ-type) with supersymmetry broken by the modulus field. We derive the possible patterns of soft supersymmetry-breaking terms, which depend in T-type models whether the Polonyi and/or matter fields are twisted or not, and in ϕ-type models on whether the inflaton and/or other matter fields are twisted or not. In ϕ-type models, we are able to directly relate the scale of supersymmetry breaking to the inflaton mass. We also discuss cosmological constraints from entropy considerations and the density of dark matter on the mechanism for stabilizing the modulus field via higher-order terms in the no-scale Kähler potential.

The Nelson-Seiberg Theorem Generalized with Nonpolynomial Superpotentials

The Nelson-Seiberg theorem relates R-symmetries to F-term supersymmetry breaking and provides a guiding rule for new physics model building beyond the Standard Model. A revision of the theorem gives a necessary and sufficient condition to supersymmetry breaking in models with polynomial superpotentials. This work revisits the theorem to include models with nonpolynomial superpotentials. With a generic R-symmetric superpotential, a singularity at the origin of the field space implies both R-symmetry breaking and supersymmetry breaking. We give a generalized necessary and sufficient condition for supersymmetry breaking which applies to both perturbative and nonperturbative models.

Generating the Cabibbo angle in flavored gauge mediation models with discrete non-Abelian symmetries

We explore the generation of fermion masses and quark mixing angles within flavored gauge mediation models of supersymmetry breaking in which the Higgs and messenger doublets are connected by a discrete non-Abelian symmetry. In this framework, the Higgs-messenger symmetry, which we take for concreteness to be the discrete group $\mathcal{S}_3$, also plays the role of a (partial) family symmetry. We investigate mechanisms for generating mass hierarchies for the lighter quark generations and generating the Cabibbo angle within this class of models. While perturbations of the couplings at the renormalizable level do not lead to phenomenologically viable quark mixing parameters, we show that the Cabibbo angle can be generated via couplings at the nonrenormalizable level and explore the phenomenological implications of this scenario.

Search for disappearing tracks in proton-proton collisions at [formula omitted

A search is presented for long-lived charged particles that decay within the volume of the silicon tracker of the CMS experiment. Such particles can produce events with an isolated track that is missing hits in the outermost layers of the silicon tracker, and is also associated with little energy deposited in the calorimeters and no hits in the muon detectors. The search for events with this “disappearing track” signature is performed in a sample of proton-proton collisions recorded by the CMS experiment at the LHC with a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 101fb−1 recorded in 2017 and 2018. The observation of 48 events is consistent with the estimated background of 47.8−2.3+2.7(stat)±8.1(syst) events. Upper limits are set on chargino production in the context of an anomaly-mediated supersymmetry breaking model for purely wino and higgsino neutralino scenarios. At 95% confidence level, the first constraint is placed on chargino masses in the higgsino case, excluding below 750 (175) GeV for a lifetime of 3 (0.05)ns. In the wino case, the results of this search are combined with a previous CMS search to produce a result representing the complete LHC data set recorded in 2015–2018, the most stringent constraints to date. At 95% confidence level, chargino masses in the wino case are excluded below 884 (474) GeV for a lifetime of 3 (0.2)ns.

Dynamics of revolving D-branes at short distances

We study the behavior of the effective potential between revolving Dp-branes at all ranges of the distance r, interpolating r » ls and r « ls (ls is the string length). Since the one-loop open string amplitude cannot be calculated exactly, we instead employ an efficient method of partial modular transformation. The method is to perform the modular transformation partially in the moduli parameter and rewrite the amplitude into a sum of contributions from both of the open and closed string massless modes. It is nevertheless free from the double counting and can approximate the open string amplitudes with less than 3% accuracy. From the D-brane effective field theory point of view, this amounts to calculating the one-loop threshold corrections of infinitely many open string massive modes. We show that threshold corrections to the ω2r2 term of the moduli field r cancel among them, where ω is the angular frequency of the revolution and sets the scale of supersymmetry breaking. This cancellation suggests a possibility to solve the hierarchy problem of the Higgs mass in high scale supersymmetry breaking models.

Combined search for supersymmetry with photons in proton-proton collisions at [formula omitted] TeV

A combination of four searches for new physics involving signatures with at least one photon and large missing transverse momentum, motivated by generalized models of gauge-mediated supersymmetry (SUSY) breaking, is presented. All searches make use of proton-proton collision data at s=13 TeV, which were recorded with the CMS detector at the LHC in 2016, and correspond to an integrated luminosity of 35.9 fb−1. Signatures with at least one photon and large missing transverse momentum are categorized into events with two isolated photons, events with a lepton and a photon, events with additional jets, and events with at least one high-energy photon. No excess of events is observed beyond expectations from standard model processes, and limits are set in the context of gauge-mediated SUSY. Compared to the individual searches, the combination extends the sensitivity to gauge-mediated SUSY in both electroweak and strong production scenarios by up to 100 GeV in neutralino and chargino masses, and yields the first CMS result combining various SUSY searches in events with photons at s=13 TeV.

On supersymmetry breaking vacua from D-branes at orientifold singularities

We present a large class of models of D-branes at (orientifold) Calabi-Yau sin- gularities which enjoy dynamical supersymmetry breaking at low energy, by means of either the SU(5) or 3–2 supersymmetry breaking models. Once embedded in a warped throat or, equivalently, in a large N theory, all models display an instability along a Coulomb branch direction towards supersymmetry preserving vacua. Interestingly, the nature of the run- away mechanism is model-independent and has a precise geometrical interpretation. This naturally suggests the properties a Calabi-Yau singularity should have in order for such instability not to occur.

Unified no-scale model of modulus fixing, inflation, supersymmetry breaking, and dark energy

We present a minimal SU(2,1)/SU(2) x U(1) no-scale model that incorporates in an economical way modulus fixing, Starobinsky-like inflation, an adjustable scale for supersymmetry breaking and the possibility of a small cosmological constant, a.k.a. dark energy.

Search for supersymmetry in final states with photons and missing transverse momentum in proton-proton collisions at 13 TeV

Results are reported of a search for supersymmetry in final states with photons and missing transverse momentum in proton-proton collisions at the LHC. The data sample corresponds to an integrated luminosity of 35.9 fb−1 collected at a center-of-mass energy of 13 TeV using the CMS detector. The results are interpreted in the context of models of gauge-mediated supersymmetry breaking. Production cross section limits are set on gluino and squark pair production in this framework. Gluino masses below 1.86 TeV and squark masses below 1.59 TeV are excluded at 95% confidence level.

Enhancing Long-Lived Particles Searches at the LHC with Precision Timing Information.

We explore the physics potential of using precision timing information at the LHC in searches for long-lived particles (LLPs). In comparison with the light standard model particles, the decay products of massive LLPs arrive at detectors with time delays around the nanosecond scale. We propose new strategies to take advantage of this time delay feature by using initial state radiation to time stamp the collision event and require at least one LLP to decay within the detector. This search strategy is effective for a broad range of models. In addition to outlining this general approach, we demonstrate its effectiveness with the projected reach for two benchmark scenarios: a Higgs boson decaying into a pair of LLPs, and pair production of long-lived neutralinos in the gauge mediated supersymmetry breaking models. Our strategy increases the sensitivity to the lifetime of the LLP by two orders of magnitude or more and particularly exhibits a better behavior with a linear dependence on the lifetime in the large lifetime region compared to traditional LLP searches. The timing information significantly reduces the standard model background and provides a powerful new dimension for LLP searches.