Supersymmetry Generators Research Articles

Inclusive search for squarks and gluinos inppcollisions ats=7 TeV

A search is performed for heavy particle pairs produced in sqrt(s) = 7 TeV proton-proton collisions with 35 inverse picobarns of data collected by the CMS experiment at the LHC. The search is sensitive to squarks and gluinos of generic supersymmetry models, provided they are kinematically accessible, with minimal assumptions on properties of the lightest superpartner particle. The kinematic consistency of the selected events is tested against the hypothesis of heavy particle pair production using the dimensionless razor variable R, related to the missing transverse energy. The new physics signal is characterized by a broad peak in the distribution of MR, an event-by-event indicator of the heavy particle mass scale. This new approach is complementary to missing transverse energy-based searches. After background modeling based on data, and background rejection based on R and MR, no significant excess of events is found beyond the standard model expectations. The results are interpreted in the context of the constrained minimal supersymmetric standard model as well as two simplified supersymmetry models.

Supersymmetric aether

It has been suggested by Groot Nibbelink and Pospelov that Lorentz invariance can be an emergent symmetry of low-energy physics provided the theory enjoys a non-relativistic version of supersymmetry. We construct a model that realizes the latter symmetry dynamically: it breaks Lorentz invariance but leaves the supersymmetry generators intact. The model is a supersymmetric extension of the dynamical aether theory of Jacobson and Mattingly. It shows rich dynamics and possesses a family of inequivalent vacua realizing different symmetry breaking patterns. In particular, we find stable vacua that break spontaneously spatial isotropy. Supersymmetry breaking terms give masses to fermionic and bosonic partners of the aether field. We comment on the coupling of the model to supergravity and on the implications for Horava gravity.

Discovery reach for generic supersymmetry at the LHC: M T2 versus missing transverse momentum selections for pMSSM searches

Different search strategies for supersymmetry have been employed by the LHC general-purpose experiments using early data. As proven by their early results, these strategies are promising, but raise the question of how well they will generalize for the future. We address this question by studying two thousand phenomenological minimal supersymmetric standard model parameter space points that come from a fit to indirect and cosmological data. We examine the 5σ discoverability of the points employing a typical ATLAS-type search based on missing transverse momentum (MET), a search based on an optimised M T2 cut and a combination of the two, taking into account standard model backgrounds. The discovery reach of the strategies can depend strongly on the systematic uncertainty in the background, subject to the stringency of the cuts and the details of the background simulation. By combining the MET and M T2 based strategies, with an integrated luminosity of 1 fb−1 (10 fb−1) at 7 TeV, 4-8%(42%) of the points are discoverable, depending on the systematic uncertainty on the background. At 14TeVand with10fb−1, 96% of the points are discoverable. While the majority of points can be discovered by both strategies at \( \sqrt {s} = 14 \) TeV and with 1fb−1, there are some that are left undiscovered by a MET search strategy, but which are discovered by the M T2 strategy, and vice versa, therefore it is essential that one performs both in parallel. We discuss some of the factors that can make points more difficult to observe.

Supersymmetric Runge–Lenz–Pauli vector for Dirac vortex in topological insulators and graphene

The Dirac mass-vortex at the surface of a topological insulator or in graphene is considered. Within the linear approximation for the vortex amplitude's radial dependence, the spectrum is a series of degenerate bound states, which can be classified by a set of accidental SU(2) and supersymmetry generators (Herbut and Lu 2011 Phys. Rev. B 83 125412). Here we discuss further the properties and manifestations of the supersymmetry of the vortex Hamiltonian, and point out some interesting analogies with the Runge–Lenz–Pauli vector in the non-relativistic hydrogen atom. Symmetry-breaking effects due to a finite chemical potential and the Zeeman field are also analyzed. We find that a residual accidental degeneracy remains only in the special case of equal magnitudes of both terms; otherwise it is removed entirely.

Twist deformations of the supersymmetric quantum mechanics

Abstract The $$ \mathcal{N} $$-extended Supersymmetric Quantum Mechanics is deformed via an abelian twist which preserves the super-Hopf algebra structure of its Universal Enveloping Superalgebra. Two constructions are possible. For even $$ \mathcal{N} $$ one can identify the 1D $$ \mathcal{N} $$-extended superalgebra with the fermionic Heisenberg algebra. Alternatively, supersymmetry generators can be realized as operators belonging to the Universal Enveloping Superalgebra of one bosonic and several fermionic oscillators. The deformed system is described in terms of twisted operators satisfying twist-deformed (anti)commutators. The main differences between an abelian twist defined in terms of fermionic operators and an abelian twist defined in terms of bosonic operators are discussed.

Discovering the constrained NMSSM with tau leptons at the LHC

The constrained Next-to-Minimal Supersymmetric StandardModel (cNMSSM) with mSugra-like boundary conditions at the GUT scale implies a singlino-like LSP with a mass just a few GeV below a stau NLSP. Hence, most of the squark/gluino decay cascades contain two τ leptons. The gluino mass ≳ 1.2 TeV is somewhat larger than the squark masses of ≳ 1 TeV. We simulate signal and background events for such a scenario at the LHC, and propose cuts on the transverse momenta of two jets, the missing transverse energy and the transverse momentum of a hadronically decaying τ lepton. This dedicated analysis allows to improve on the results of generic supersymmetry searches for a large part of the parameter space of the cNMSSM. The distribution of the effective mass and the signal rate provide sensitivity to distinguish the cNMSSM from the constrained Minimal Supersymmetric Standard Model in the stau-coannihilation region.

Formula omitted]-invariant decomposition of ten-dimensional Yang–Mills supersymmetry

The N=1, d=10 super Yang–Mills action is constructed in a twisted form, using SU(5) invariant decomposition of spinors in 10 dimensions. The action and its off-shell closed twisted scalar supersymmetry operator Q is derived from a Chern–Simons term. The action can be decomposed as the sum of a term in the cohomology of Q and of a term that is Q-exact. The first term is a fermionic Chern–Simons term for a twisted component of the Majorana–Weyl gluino and it is related to the second one by a twisted vector supersymmetry with 5 parameters. The cohomology of Q and some topological observables are defined from descent equations. In this SU(5)⊂SO(10) invariant decomposition, the N=1, d=10 theory is determined by only 6 supersymmetry generators, as in the twisted N=4, d=4 theory. There is a superspace with 6 twisted fermionic directions, with solvable constraints.

Supersymmetry algebra cohomology. I. Definition and general structure

This paper concerns standard supersymmetry algebras in diverse dimensions, involving bosonic translational generators and fermionic supersymmetry generators. A cohomology related to these supersymmetry algebras, termed supersymmetry algebra cohomology, and corresponding “primitive elements” are defined by means of a BRST (Becchi-Rouet-Stora-Tyutin)-type coboundary operator. A method to systematically compute this cohomology is outlined and illustrated by simple examples.

Self-isospectrality, mirror symmetry, and exotic nonlinear supersymmetry

We study supersymmetry of a self-isospectral one-gap Poschl-Teller system in the light of a mirror symmetry that is based on spatial and shift reflections. The revealed exotic, partially broken nonlinear supersymmetry admits seven alternatives for a grading operator. One of its local, first order supercharges may be identified as a Hamiltonian of an associated one-gap, non-periodic Bogoliubov-de Gennes system. The latter possesses a nonlinear supersymmetric structure, in which any of the three non-local generators of a Clifford algebra may be chosen as the grading operator. We find that the supersymmetry generators for the both systems are the Darboux-dressed integrals of a free spin-1/2 particle in the Schrodinger picture, or of a free massive Dirac particle. Nonlocal Foldy- Wouthuysen transformations are shown to be involved in the supersymmetric structure.

Mass-deformed BLG theory in light-cone superspace

Maximally supersymmetric mass deformation of the Bagger–Lambert–Gustavsson (BLG) theory corresponds to a non-central extension of the d = 3 N = 8 Poincaré superalgebra (allowed in three dimensions). We obtain its light-cone superspace formulation which has a novel feature of the dynamical supersymmetry generators being cubic in the kinematical ones. The mass deformation picks a quaternionic direction, described by Ωmn, which breaks the SO(8) R-symmetry down to SO(4) × SO(4). The Hamiltonian of the theory is shown to be a quadratic form of the dynamical supersymmetry transformations to all orders in the mass parameter, M, and the structure constants, fabcd.

Flavor violation in supersymmetricQ6model

We investigate flavor violation mediated by Higgs bosons and supersymmetric particles in a predictive class of models based on the non-Abelian flavor symmetry ${Q}_{6}$. These models, which aim to reduce the number of parameters of the fermion sector and to solve the flavor changing problems of generic supersymmetry (SUSY) setup, assume three families of Higgs bosons and spontaneous or soft violation of $CP$ symmetry. Tree-level contributions to meson-antimeson mixings mediated by Higgs bosons are shown to be within experimental limits for Higgs masses in the (1--5) TeV range. Calculable flavor violation induced by SUSY loops are analyzed for meson mixing and lepton decays and found to be consistent with data. Significant new SUSY contributions arise in ${B}_{s}--{\overline{B}}_{s}$ mixing, but nonstandard $CP$ violation is suppressed. A simple solution to the SUSY $CP$ problem is found, which requires light Higgsinos.

ONE-DIMENSIONAL σ-MODELS WITH N = 5, 6, 7, 8 OFF-SHELL SUPERSYMMETRIES

We computed the actions for the one-dimensional (1D)N = 5 σ-models with respect to the two inequivalent (2, 8, 6) multiplets. Four supersymmetry generators are manifest, while the constraint originated by imposing the fifth supersymmetry automatically induces a full N = 8 off-shell invariance. The resulting action coincides in the two cases and corresponds to a conformally flat 2D target satisfying a special geometry of rigid type. To obtain these results we developed a computational method (for Maple 11) which does not require the notion of superfields and is instead based on the nowadays available list of the inequivalent representations of the 1DN-extended supersymmetry. Its application to systematically analyze the σ-models off-shell invariant actions for the remaining N = 5, 6, 7, 8(k, 8, 8-k) multiplets, as well as for the N>8 representations, only requires more cumbersome computations.

Second Hopf map and supersymmetric mechanics with a Yang monopole

We propose to use the second Hopf map for the reduction [via $SU(2)$ group action] of the eight-dimensional $\mathcal{N}=8$ supersymmetric mechanics to five-dimensional supersymmetric systems specified by the presence of an $SU(2)$ Yang monopole. For our purpose we develop the relevant reduction procedure. The reduced system is characterized by its invariance under the $\mathcal{N}=5$ or $\mathcal{N}=4$ supersymmetry generators (with or without an additional conserved Becchi-Rouet-Stora-Tyutin charge operator) which commute with the $su(2)$ generators.

Matrix reduction and thesu(2∣2)superalgebra in AdS/CFT correspondence

We study the supersymmetry generators $Q$, $S$ on the 1-loop vectorless sector of $\mathcal{N}=4$ super Yang-Mills theory, by reduction to the plane-wave matrix model. Using a coherent basis in the $\mathfrak{s}\mathfrak{u}(2\ensuremath{\mid}2)$ sector, a comparison with the algebra given by Beisert is presented, and some parameters (up to one loop) are determined. We make a final comparison of these supercharges with the results that can be obtained from the string action by working in the light-cone gauge and discretizing the string.

CERN LHC signals for a neutrino mass model with bilinear R-parity violating minimal anomaly mediated supersymmetry

We investigate a neutrino mass model in which the neutrino data is accounted for by bilinear R-parity violating supersymmetry with anomaly mediated supersymmetry breaking. We focus on the CERN Large Hadron Collider (LHC) phenomenology, studying the reach of generic supersymmetry search channels with leptons, missing energy and jets. A special feature of this model is the existence of long-lived neutralinos and charginos which decay inside the detector leading to detached vertices. We demonstrate that the largest reach is obtained in the displaced vertices channel and that practically all of the reasonable parameter space will be covered with an integrated luminosity of $10\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$. We also compare the displaced vertex reaches of the LHC and Tevatron.

One-loop divergences in the two-dimensional non-anticommutative supersymmetric σ-model

We discuss the structure of the non-anticommutative = 2 non-linear σ-model in two dimensions, constructing differential operators which implement the deformed supersymmetry generators and using them to reproduce the classical action. We then compute the one-loop quantum corrections and express them in a more compact form using the differential operators.

Topological Membranes

Introducing membranes as fundamental object in topological M-theory, we explore the global supersymmetry as well as the local κ-symmetry of the theory. Promoting the supersymmetry generators to be BRST operators, it is shown that the action can be chosen to be BRST exact. The presentation is given along the lines of [L. Bao, V. Bengtsson, M. Cederwall and B. E. W. Nilsson, JHEP 0601, 150 (2006) [arXiv:hep-th/0507077]].

Ten-dimensional super-Yang–Mills with nine off-shell supersymmetries

After adding 7 auxiliary scalars to the d=10 super-Yang–Mills action, 9 of the 16 supersymmetries close off-shell. In this Letter, these 9 supersymmetry generators are related by dimensional reduction to scalar and vector topological symmetry in N=2, d=8 twisted super-Yang–Mills. Furthermore, a gauge-invariant superspace action is constructed for d=10 super-Yang–Mills where the superfields depend on 9 anticommuting θ variables.

Three-dimensional nonanticommutative superspace

We propose two alternative formulations for a three-dimensional non-anticommutative superspace in which some of the fermionic coordinates obey Clifford anticommutation relations. For this superspace, we construct the supersymmetry generators satisfying standard anticommutation relations and the corresponding supercovariant derivatives. We formulate a scalar superfield theory in such a superspace and calculate its propagator. We also suggest a prescription for the introduction of interactions in such theories.

New supersymmetric solutions inN= 2 matter coupledAdS3supergravities

We construct new 1/2 supersymmetric solutions in D=3, N=2, matter coupled, U(1) gauged supergravities and study some of their properties. We do this by employing a quite general supersymmetry breaking condition, from which we also redrive some of the already known solutions. Among the new solutions, we have an explicit non-topological soliton for the non-compact sigma model, a locally flat solution for the compact sigma model and a string-like solution for both types of sigma models. The last one is smooth for the compact scalar manifold.