The Fermi-Lab Collaboration has announced the results for the measurement of muon anomalous magnetic moment. Combining with the previous results by the BNL experiment, we have $4.2 σ$ deviation from the Standard Model (SM), which strongly implies the new physics around 1 TeV. To explain the muon anomalous magnetic moment naturally, we analyze the corresponding five Feynman diagrams in the Supersymetric SMs (SSMs), and show that the Electroweak Supersymmetry (EWSUSY) is definitely needed. We realize the EWSUSY in the Minimal SSM (MSSM) with Genernalized Mininal Supergravity (GmSUGRA). We find large viable parameter space, which is consistent with all the current experimental constraints. In particular, the Lightest Supersymmetric Particle (LSP) neutralino can be at least as heavy as 550 GeV. Most of the viable parameter space can be probed at the future HL-LHC, while we do need the future HE-LHC to probe some viable parameter space. However, it might still be challenge if R-parity is violated.
Considering the Generalized Minimal Supergravity Model (GmSUGRA) in the Minimal Supersymmetric Standard Model (MSSM), we study the Electroweak Supersymmetry (EWSUSY), where the squarks and/or gluino are heavy around a few TeVs while the sleptons, sneutrinos, Bino, Winos, and/or Higgsinos are light within one TeV. We resolves the $(g_μ-2)/2$ discrepancy for the muon anomalous magnetic moment in the Standard Model (SM) successfully and identifies a parameter space where such solutions also have the electroweak fine-tuning measures $Δ_{EW}~16.5$ (6$\%$) and $Δ_{EW}~25$ (4$\%$) without and with th…
We study natural supersymmetry in the Generalized Minimal Supergravity (GmSUGRA). For the parameter space with low energy electroweak fine-tuning measures less than 50, we are left with only the $Z$-pole, Higgs-pole and Higgsino LSP scenarios for dark matter (DM). We perform the focused scans for such parameter space and find that it satisfies various phenomenological constraints and is compatible with the current direct detection bound on neutralino DM reported by the LUX experiment. Such parameter space also has solutions with correct DM relic density besides the solutions with DM relic dens…
In the GmSUGRA scenario with the high-dimensional operators containing the GUT Higgs fields, we systematically studied the supersymmetry breaking scalar masses, SM fermion Yukawa coupling terms, and trilinear soft terms in the E_6 SUSY GUT model where the gauge symmetry is broken down to the SO(10)\tm U(1) gauge symmetry, SU(3)_C\times SU(3)_L \times SU(3)_R gauge symmetry, SU(6)\times SU(2)_a (a={\rm L,R,X}) gauge symmetry, flipped SU(5) gauge symmetry etc. In addition, we considered the scalar and gaugino mass relations, which can be preserved from the GUT scale to the electroweak scale unde…
Inspired by the phenomenological constraints, LHC supersymmetry and Higgs searches, dark matter search as well as string model building, we propose the electroweak supersymmetry around the electroweak scale: the squarks and/or gluinos are around a few TeV while the sleptons, sneutrinos, bino and winos are within one TeV. The Higgsinos can be either heavy or light. We consider bino as the dominant component of dark matter candidate, and the observed dark matter relic density is achieved via the neutralino-stau coannihilations. Considering the Generalized Minimal Supergravity (GmSUGRA), we show …
We present the two-loop $β$-functions for non-standard soft supersymmetry-breaking couplings including non-standard R-parity violating soft terms in the Minimal Supersymmetric Standard Model
In the generalized minimal supergravity (GmSUGRA) scenario, we systematically study the supersymmetry breaking scalar masses, Standard Model fermion Yukawa coupling terms, and trilinear soft terms in SU(5) models with the Higgs fields in the {\bf 24} and {\bf 75} representations, and in SO(10) models where the gauge symmetry is broken down to the Pati-Salam SU(4)_C X SU(2)_L X SU(2)_R gauge symmetry, SU(3)_C X SU(2)_L X SU(2)_R X U(1)_{B-L} gauge symmetry, George-Glashow SU(5) X U(1)' gauge symmetry, flipped SU(5) X U(1)_X gauge symmetry, and SU(3)_C X SU(2)_L X U(1)_1 X U(1)_2 gauge symmetry.…
Supersymmetric models with broken R-parity provide mechanisms that allow to generate Majorana neutrino masses and magnetic moments through virtual particle-sparticle loops. This constitutes an attractive alternative to the see-saw mechanism. In this paper we present a detailed calculation of the transition magnetic moments of a Majorana neutrino in gauge mediated supersymmetry breaking MSSM without R-parity. We base our analysis on the renormalization group evolution of the MSSM parameters, which are unified at the GUT scale.
The R-parity non-conservation phenomenology within the minimal supersymmetric standard model with gauge mediated supersymmetry breaking has been studied. New constraints on the lepton number violating constant $λ_{111}^\prime$ were imposed by non-observability of the neutrinoless double beta decay. We find that $λ_{111}^\prime$ depends strongly on the effective supersymmetry breaking scale $Λ$ only and deduce limits which are much stronger than those previously found in literature.
The possibility of generating a large trilinear $A_t$ soft supersymmetry breaking coupling at low energies through renormalisation group evolution in the 5D MSSM is investigated. Using the power law running in five dimensions and a compactification scale in the 10-$10^3$ TeV range, to show that gluino mass may drive a large enough $A_t$ to reproduce the measured Higgs mass and have a light stop superpartner below $\sim 1$ TeV as preferred by the fine tuning argument for the Higgs mass.
An introduction to the minimal supersymmetric Standard Model (MSSM) is given. The motivation for ``low-energy'' supersymmetry is reviewed, and the structure of the MSSM is outlined. In its most general form, the MSSM can be viewed as a low-energy effective theory parametrized by a set of arbitrary soft-supersymmetry-breaking parameters. A variety of techniques for reducing the parameter freedom of the MSSM are surveyed. The search for supersymmetry below and above the threshold for supersymmetric particle production presents a challenging task for experimentalists at present and future collide…
A fairly elementary introduction to supersymmetric field theories in general and the minimal supersymmetric Standard Model (MSSM) in particular is given. Topics covered include the cancellation of quadratic divergencies, the construction of the supersymmetric Lagrangian using superfields, the field content of the MSSM, electroweak symmetry breaking in the MSSM, mixing between different superparticles (current eigenstates) to produce mass eigenstates, and the embedding of the MSSM in so--called minimal supergravity.
Collisions of non-topological solitons, Q-balls, are studied in a typical potential in the Minimal Supersymmetric Standard Model where supersymmetry has been broken by a gravitationally coupled hidden sector. Q-ball collisions are studied numerically on a two dimensional lattice for a range of Q-ball charges. Total cross-sections, as well as cross-sections for fusion and charge-exchange are calculated. The average percentage increase in charge carried by the largest Q-ball after a collision is found to be weakly dependent on the initial charge.
Collisions of non-topological solitons, Q-balls, are considered in the Minimal Supersymmetric Standard Model where supersymmetry has been broken at a low energy scale via a gauge mediated mechanism. Q-ball collisions are studied numerically on a two dimensional lattice for a range of Q-ball charges. Total cross-sections, as well as fusion and geometrical cross-sections are calculated. The total and geometrical cross-sections appear to converge with increasing charge. The fusion cross-section has been estimated to be larger than 60% of the geometrical cross-section for large balls.
These lecture notes are from a first course on the Minimal Supersymmetric Standard Model. The level of the notes is introductory and pedagogical. Standard Model, basic supersymmetry algebra and its representations are considered as prerequisites. The topics covered include particle content, structure of the lagrangian, supersymmetry breaking soft terms, electroweak symmetry breaking and the sparticle mass spectrum. Popular supersymmetry breaking models like minimal supergravity and gauge mediation are also introduced.
The Minimal Supersymmetric Standard Model (MSSM) can include two soft breaking terms which are often neglected: a non-analytic scalar trilinear coupling and a Higgsino bilinear term. A set of high-scale boundary conditions consistent with the reparameterisation invariance which the model possesses is obtained. The three-family renormalisation group equations for the MSSM with these terms are presented. The ranges of the universal high-scale values of these couplings which lead to an acceptable TeV-scale theory are obtained, as is the supersymmetric particle spectrum at this scale. The effect o…
Excited Q-balls are studied by numerical simulations in the Minimal Supersymmetric Standard Model with supersymmetry broken by a gravity mediated mechanism. It is found that there is a suppression factor of $\cO(10^{-2})$ in the rate at which a Q-ball can emit their excess energy compared to the rate set by the dynamical scale of the field, $m$. Furthermore, it is noted that a Q-ball can withstand a large amount of excess energy without losing a significant amount of its charge. The cosmological importance of these properties are considered for Q-balls in the thermal bath of the early universe…
These lectures, presented at the 2006 TASI summer school, give a general introduction to supersymmetry, emphasizing its application to models of elementary particle physics at the 100 GeV energy scale. I discuss the following topics: the construction of supersymmetric Lagrangians with scalars, fermions, and gauge bosons, the structure and mass spectrum of the Minimal Supersymmetric Standard Model (MSSM), the measurement of the parameters of the MSSM at high-energy colliders, and the solutions that the MSSM gives to the problems of electroweak symmetry breaking and dark matter.
We study the most general extension of the MSSM Lagrangian that includes scenarios in which supersymmetry is spontaneously broken at a low scale f. The spurion that parametrizes supersymmetry breaking in the MSSM is promoted to a dynamical superfield involving the goldstino, with (and without) its scalar superpartner, the sgoldstino. The low energy effective Lagrangian is written as an expansion in terms of m_{SUSY}/sqrt{f}, where m_{SUSY} is the induced supersymmetry breaking scale, and contains, in addition to the usual MSSM Lagrangian with the soft terms, couplings involving the component f…
We study the Minimal Supersymmetric Standard Model (MSSM) with large gluino mass m_{\tilde{g}} >> 1 TeV. In particular, we discuss the LHC supersymmetry discovery signatures with n leptons + jets + E^{miss}_T, n >= 0 for the MSSM with large gluino mass. We show that for some relations among squark and neutralino masses leptonic signatures with n leptons + jets + E^{miss}_T, n >= 1 do not allow to discover supersymmetry at the LHC and the only supersymmetry discovery signature remains the signature with no leptons + jets + E^{miss}_T. Moreover, for LSP mass close to squark masses the LHC discov…
We present a five-dimensional model compactified on an interval where supersymmetry is broken by the Scherk-Schwarz mechanism. The gauge sector propagates in the bulk, two Higgs hypermultiplets are quasilocalized, and quark and lepton multiplets localized, in one of the boundaries. The effective four-dimensional theory is the MSSM with very heavy gauginos, heavy squarks and light sleptons and Higgsinos. The soft tree-level squared masses of the Higgs sector can be negative and they can (partially) cancel the positive one-loop contributions from the gauge sector. Electroweak symmetry breaking c…
We present here the results for Higgs and Supersymmetry prospective searches at the Large Hadron Collider. We show that for one year at high luminosity, Standard Model and MSSM Higgs should be observed within the theoretically expected mass range. MSUGRA and restricted phenomenological MSSM searches lead to discovery of up to 2.5 TeV squarks and gluinos.
We investigate the muon anomalous magnetic dipole moment (MDM), the muon electric dipole moment (EDM) and the lepton-flavour-violating decays of the $τ-$lepton, $τ\to μγ$ and $τ\to 3μ$, in the CP-violating Minimal Supersymmetric Standard Model (MSSM) with nonuniversal soft-supersymmetry breaking. We evaluate numerically the muon EDM and the branching ratios $B(τ\to μγ)$ and $B(τ\to 3μ)$, after taking into account the experimental constraints from the electron EDM and muon MDM. Upon imposition of the experimental limits on our theoretical predictions for the aforementioned branching ratios and …
In the framework of the MSSM the non-universal boundary conditions of soft SUSY breaking parameters are considered. Taking as input the top, bottom and Z-boson masses, the values of the gauge couplings at the EW scale and the infrared quasi-fixed points for Yukawa couplings and the soft parameters the mass of the lightest CP-even Higgs boson is found to be m_h=92.7^{+10}_{-4.9} +- 5 +- 0.4 GeV/c^2 for the low \tanβcase and m_h=125.7^{+6.4}_{-9.0} +- 5 +- 0.4 GeV/c^2 (μ> 0) or m_h =125.4^{+6.6}_{-9.0} +-5 +- 0.4 GeV/c^2 (μ< 0) in the case of large $\tanβ$.
Possible realistic scenarios are investigated in the minimal supersymmetric standard model (MSSM) Higgs sector extended by dimension-six effective operators. The CP-odd Higgs boson with low mass around 30--90 GeV could be consistently introduced in the regime of large threshold corrections to the effective MSSM two-doublet Higgs potential.
The predictions of the \sm and the minimal supersymmetric standard model (MSSM) for the electroweak precision parameters are discussed in the light of the recent precision data. The results from global fits yield lower $χ^2$ values in the MSSM than in the Standard model. The fits prefer regions in the MSSM parameter space with $M_2 \simeq |μ| $ and allow chargino masses higher than the present exclusion limits of LEP 1.5.
The prospects for discovering neutral Higgs bosons in the minimal supersymmetric model (MSSM) and in the minimal supergravity model at the LHC are investigated. Two special discovery channels are discussed: (i) the decay mode of the MSSM CP-odd Higgs boson into photon pairs, and (ii) the decays of neutral Higgs bosons into muon pairs in the MSSM as well as in the minimal supergravity model.
Up until now a complete scan in all phenomenologically relevant directions of the MSSM at the TeV scale for performing global fit has not been done. Given the imminent start of operation of the LHC, this is a major gap on our quest to discovering and understanding the physical implications of low energy supersymmetry. The main reason for this is the large number of parameters involved that makes it computationally extremely expensive using the traditional methods. In this talk I demonstrate that with advanced sampling techniques the problem is solvable. The results from the explored 24-paramet…
We study the dependence of the Higgs boson mass on the supersymmetry breaking scale in the minimal supersymmetric extension of the standard Weinberg-Salam model. In particular, we find that for supersymmetry breaking scale $10^8$ GeV $\leq M_s \leq 10^{16}$ GeV and for $m^{pole}_{top} = 175 \pm 5 $ GeV the Higgs boson mass is 120 GeV $ \leq m_h \leq 160 $ GeV
We study the predictions for M_top, tan(beta) and V_cb in a popular texture ansatze for the fermion mass matrices. We do this both for the Minimal Supersymmetric Standard Model (MSSM) and for the simplest model (MSSM-BRpV) where a bilinear R-Parity violating term is added to the superpotential. We find that taking the experimental values for M_top and V_cb at 99 % C.L. and the GUT relations h_b=h_tau and (V_cb)^2=h_c/h_t within 5 %, the large tan(beta) solution, characteristic in the MSSM with bottom--tau unification, becomes disallowed. In contrast the corresponding allowed region for the MSS…
In the framework of the effective field theory approach to heavy supersymmetry radiative corrections in the Higgs sector of the Minimal Supersymmetric Standard Model (MSSM) for the effective potential decomposition up to the dimension-six operators are calculated. Symbolic expressions for the threshold corrections induced by $F$- and $D$- soft supersymmetry breaking terms are derived and the Higgs boson mass spectrum respecting the condition $m_h=$125 GeV for the lightest $CP$-even scalar is evaluated.
We have recently completed a detailed scan of the 19-dimensional parameter space of the phenomenological MSSM, i.e., the CP-conserving MSSM assuming Minimal Flavor Violation(MFV) with the first two sfermion generations degenerate. We found a large set of parameter space points that satisfied all of the existing experimental and theoretical constraints. This analysis allows us to examine the general features of the MSSM without reference to any particular SUSY breaking scenario or any other assumptions about physics at higher scales. This study opens up new possibilities for SUSY phenomenology …
We consider a supersymmetric realization of the MSSM Higgs sector, where the soft terms are promoted to supersymmetric operators and a minimal weakly coupled hidden sector is included. The model exhibits long-lived meta-stable vacua in which supersymmetry and electroweak symmetry are spontaneously broken. The spectrum contains, in addition to the usual MSSM particles and the goldstino fermion, a CP-even and a CP-odd scalar in the neutral Higgs sector corresponding to the complex sgoldstino scalar. By treating all the components of the goldstino supermultiplet dynamically and taking into accoun…
Supersymmetric extensions of the standard model generically contain additional sources of CP violation. We discuss how at one loop a potentially large CP violating coupling of the lightest Higgs, h^0, to leptons is induced in the minimal supersymmetric standard model (MSSM). The CP violating couplings of h^0 in extensions of the MSSM, such as the next-to-minimal supersymmetric standard model (NMSSM) are also considered. We indicate how this CP violation might be observed; in particular a polarization-dependent production asymmetry, in the context of a muon collider, provides a means to access …
We present an overview of direct and indirect constraints in the MSSM, in CP-conserving and CP-violating MSSM scenarios, with some emphasis on the importance of combining the constraints from different sectors, namely SUSY and Higgs direct searches at the LHC, flavour physics, dark matter and electric dipole moments.
We calculate the leading contribution to the left-right asymmetry in polarized Møller scattering from the superpartners in the Minimal Supersymmetric Standard Model (MSSM), using an effective lagrangian approach. We determine the maximum asymmetry that can result from the superpartners in the MSSM under different scenarios, and discuss the feasibility of a high-precision, low-energy ($\sqrt{s}\approx 200~{\rm MeV}$) Møller scattering experiment to see supersymmetry.
These notes are an expanded version of a short course of lectures given for graduate students in particle physics at Oxford. The level was intended to be appropriate for students in both experimental and theoretical particle physics.The purpose is to present an elementary and self-contained introduction to SUSY that follows on, relatively straightforwardly, from graduate-level courses in relativistic quantum mechanics and introductory quantum field theory. The notation adopted, at least initially, is one widely used in RQM courses, rather than the `spinor calculus' (dotted and undotted indices…
We study the correlation of quantum effects on the ratios R_b and R_c within the framework of the MSSM. While in the SM the quantity R_b is in discrepancy with experiment at the 2 σlevel from below, and R_c differs from the experimental result at the 1.5 σlevel from above, the theoretical prediction for both observables could simultaneously improve in the MSSM, provided that \tanβis large enough (\tanβ\sim m_t/m_b) and there exists a light supersymmetric pseudoscalar Higgs, and also a light stop and a light chargino, all of them in the 50 GeV ballpark. In view of the masses predicted for these…
We consider the minimal supersymmetric extension of the Standard Model (MSSM) with varying amounts of non-universality in the soft supersymmetry-breaking contributions to the Higgs scalar masses. In addition to the constrained MSSM (CMSSM) in which these are universal with the soft supersymmetry-breaking contributions to the squark and slepton masses at the input GUT scale, we consider scenarios in which both the Higgs scalar masses are non-universal by the same amount (NUHM1), and scenarios in which they are independently non-universal (NUHM2). We show how the NUHM1 scenarios generalize the (…
Low-energy supersymmetry is a theoretical extension of the Standard Model of particle physics in which supersymmetry is invoked to explain the origin of the electroweak scale. In this approach, the energy scale of supersymmetry breaking can be no larger than about 1 TeV. In these lectures, a pedagogical account of softly broken supersymmetric gauge theories is presented. The minimal supersymmetric extension of the Standard Model (MSSM) is defined and constraints on its parameters are explored. The implications of supersymmetric tree-level interactions and its one-loop corrections are discussed…
The solution to fine tuning is one of the principal motivations for supersymmetry. However constraints on the parameter space of the Minimal Supersymmetric Standard Model (MSSM) suggest it may also require fine tuning (although to a much lesser extent). To compare this tuning with different extensions of the Standard Model (including other supersymmetric models) it is essential that we have a reliable, quantitative measure of tuning. We review the measures of tuning used in the literature and propose an alternative measure. We apply this measure to several toy models and the MSSM with some int…
Gauge coupling unification is studied in the MSSM with non-universal soft supersymmetry breaking terms. If gaugino masses are sufficiently smaller than scalar soft masses and the scalar soft masses have also certain types of non-universality, gauge coupling unification scale can be larger than $3\times 10^{16}$~GeV even within the MSSM contents. String unification may not need a large threshold correction or a large modulus value. We also discuss the relation to the string model building.
We discuss the phenomenology of charged Higgs bosons in the MSSM with minimal flavor violation. In addition to the constrained MSSM (CMSSM) with universal soft supersymmetry breaking mass parameters at the GUT scale, we explore non-universal Higgs mass models (NUHM) where this universality condition is relaxed. To identify the allowed parameter space regions, we apply constraints from direct searches, low energy observables, and cosmology. We find that values of the charged Higgs mass as low as $m_{H^+}\simeq~135$ GeV can be accommodated in the NUHM models, but that several flavor physics obse…
We study a supersymmetry breaking mechanism in the context of a minimal anomalous extension of the MSSM. The anomaly cancellation mechanism is achieved through suitable counterterms in the effective action, i.e. Green-Schwarz terms. We assume that the standard MSSM superpotential is perturbatively realized, i.e. all terms allowed by gauge symmetries, except for the $μ$-term which has a non-perturbative origin. The presence of this term is expected in many intersecting D-brane models which can be considered as the ultraviolet completion of our model. We show how soft supersymmetry breaking term…
Within the MSSM framework and with purely anomaly mediated supersymmetry breaking the slepton masses turn out to be tachyonic. We resolve this problem by introducing an anomaly free U(1) gauge symmetry which provides positive $D$-term contributions to sparticle masses squared that are flavor conserving at one loop. Two realistic examples based on SU(5) are presented. With U(1) spontaneously broken at a scale $\sim 10^{16}$ GeV, the right handed neutrinos acquire masses $\stackrel{<}{_\sim}10^{14}$ GeV. This breaking scale of U(1) also plays an important role in the proposed resolution of the M…
These lectures provide a phenomenological introduction to supersymmetry, concentrating on the minimal supersymmetric extension of the Standard Model (MSSM). In the first lecture, motivations are provided for thinking that supersymmetry might appear at the TeV scale, including the naturalness of the mass hierarchy, gauge unification and the probable mass of the Higgs boson. In the second lecture, simple globally supersymmetric field theories are introduced, with the emphasis on features important for model-building. Supersymmetry breaking and local supersymmetry (supergravity) are introduced in…
We show that all CP violation in the MSSM could originate in the supersymmetry breaking sector rather than the CKM matrix, and discuss the important consequences for $B$-physics.
We investigate a modification of anomaly-mediated supersymmetry breaking (AMSB) with an exotic U(1)_x gauge sector that can solve the tachyonic slepton problem of minimal AMSB scenarios. The new U(1)_x multiplet is assumed to couple directly to the source of supersymmetry breaking, but only indirectly to the minimal supersymmetric Standard Model (MSSM) through kinetic mixing with hypercharge. If the MSSM sector is also sequestered from the source of supersymmetry breaking, the contributions to the MSSM soft terms come from both AMSB and the U(1)_x kinetic coupling. We find that this arrangemen…
The connection between the scales of $ {\rm SU} (2)\times {\rm U} (1) $ gauge symmetry breaking and supersymmetry breaking is didactically displayed in the framework of a T.O.Y. (Theory Overestimating Yukawas) model, a version of the $ (M+1)SSM $ (supersymmetric extension of the standard model with a gauge singlet) in which the relevant parameters are determined in the fixed point regime. Some conspicuous features of supersymmetric particle physics are reviewed in the light of this simplified model. An alternative theory corresponding to lim $ (M+1)SSM \longrightarrow MSSM, $ leads to interest…
In the Minimal Supersymmetric Standard Model (MSSM), the masses of the charged Higgs boson ($H^\pm$) and the CP-odd scalar ($A$) are related by $M_{H^+}^2=M_A^2+m_W^2$. Furthermore, because the coupling of $W^-$-$A$-$H^+$ is fixed by gauge interaction, the tree level production rate of $q \bar q' \to W^{\pm \ast} \to A H^\pm$ depends only on one supersymmetry parameter --the mass ($M_A$) of $A$. We show that to a good approximation this conclusion also holds at the one-loop level. Consequently, this process can be used to distinguish MSSM from its alternatives (such as a general two-Higgs-doub…
We introduce a new confining force (μ-color) at TeV scale to dynamically generate a supersymmetry preserving mass scale which would replace the μparameter in the minimal supersymmetric standard model (MSSM). We discuss the Higgs phenomenology and also the pattern of soft supersymmetry breaking parameters allowing the correct electroweak symmetry breaking within the μ-color model, which have quite distinctive features from the MSSM and also from other generalizations of the MSSM.
We study the $e^{\pm}μ^{\mp} + E^{miss}_T$ and $l^+l^- + E^{miss}_T$ signatures $(l = e, μ)$ for different values of $\tanβ$ in the mSUGRA model. With $\tanβ$ rising, we observe a characteristic change in the shape of dilepton mass spectra in $l^+l^- + E^{miss}_T $ versus $e^{\pm}μ^{\mp}$ final states reflecting the decrease of $\tildeχ^0_2 \to l^+l^- \tilde{χ^0_1}$ branching ratio. We also study the non mSUGRA modifications of the CMS test point LM1 with arbitrary relations among gaugino and higgsino masses. For such modifications of the mSUGRA test point LM1 the number of lepton events depen…
We examine charge/colour breaking along directions in supersymmetric field space which are F and D-flat. We catalogue the dangerous directions and include some new ones which have not previously been considered. Analytic expressions for the resulting constraints are provided which are valid for all patterns of supersymmetry breaking. As an example we consider a recently proposed pattern of supersymmetry breaking derived in Horava-Witten M-theory, and show that there is no choice of parameters for which the physical vacuum is a global minimum.
We consider an extension of the MSSM with an added vectorlike top partner. Our aim is to revisit to what extent such an extension can raise the Higgs boson mass through radiative corrections and help ameliorate the MSSM hierarchy problem, and to specify what experimental probes at the LHC will find or exclude this possibility during the high-luminosity phase. Direct detection, precision electroweak and precision Higgs analyses are all commissioned to this end. To achieve the $ 125 \, \textrm{GeV} \ $ Higgs boson mass, we find that superpartner masses can be reduced by a factor of more than thr…
Neutrinoless double beta decay ($\znbb$) induced by superparticle exchange is investigated. Such a supersymmetric (SUSY) mechanism of $\znbb$ decay arises within SUSY theories with R-parity non-conservation (\rp). We consider the minimal supersymmetric standard model (MSSM) with explicit \rp terms in the superpotential (\rp MSSM). The decay rate for the SUSY mechanism of $\znbb$ decay is calculated. Numerical values for nuclear matrix elements for the experimentally most interesting isotopes are calculated within pn-QRPA. Constraints on the \rp MSSM parameter space are extracted from current e…
SUSYGEN is a Monte Carlo program designed for computing distributions and generating events for MSSM sparticle production in e+ e- collisions. The Supersymmetric (SUSY) mass spectrum may either be supplied by the user, or can alternatively be calculated in two different models of SUSY Breaking: gravity mediated supersymmetry breaking (SUGRA), and gauge mediated supersymmetry breaking (GMSB). The program incorporates the most important production processes and decay modes, including the full set of R-parity violating decays, and the decays to the gravitino in GMSB models. Initial state radiatio…
