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Post Info TOPIC: Supersymmetry
Blobrana


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RE: Supersymmetry
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Title: Where is SUSY?
Authors: C. Beskidt (1), W. de Boer (1), D. I. Kazakov (2,3), F. Ratnikov (1,3) ((1) Karlsruhe Institute of Technology, Germany, (2) Bogoliubov Laboratory of Theoretical Physics, JINR, Dubna, Russia, (3) ITEP, Moscow, Russia)

The direct searches for Superymmetry at colliders can be complemented by direct searches for dark matter (DM) in underground experiments, if one assumes the Lightest Supersymmetric Particle (LSP) provides the dark matter of the universe. It will be shown that within the Constrained minimal Supersymmetric Model (CMSSM) the direct searches for DM are complementary to direct LHC searches for SUSY and Higgs particles using analytical formulae. A combined excluded region from LHC, WMAP and XENON100 will be provided, showing that within the CMSSM gluinos below 1 TeV and LSP masses below 160 GeV are excluded (m_{1/2} > 400 GeV) independent of the squark masses.

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Blobrana


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Title: The Two Faces of Anomaly Mediation
Authors: Francesco D'Eramo, Jesse Thaler, Zachary Thomas

Anomaly mediation is a ubiquitous source of supersymmetry (SUSY) breaking which appears in almost every theory of supergravity. In this paper, we show that anomaly mediation really consists of two physically distinct phenomena, which we dub "gravitino mediation" and "Kahler mediation". Gravitino mediation arises from minimally uplifting SUSY anti-de Sitter (AdS) space to Minkowski space, generating soft masses proportional to the gravitino mass. Kahler mediation arises when visible sector fields have linear couplings to SUSY breaking in the Kahler potential, generating soft masses proportional to beta function coefficients. In the literature, these two phenomena are lumped together under the name "anomaly mediation", but here we demonstrate that they can be physically disentangled by measuring associated couplings to the goldstino. In particular, we use the example of gaugino soft masses to show that gravitino mediation generates soft masses without corresponding goldstino couplings. This result naively violates the goldstino equivalence theorem but is in fact necessary for supercurrent conservation in AdS space. Since gravitino mediation persists even when the visible sector is sequestered from SUSY breaking, we can use the absence of goldstino couplings as an unambiguous definition of sequestering.

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Blobrana


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Title: Gravitational Wave Probe of High Supersymmetry Breaking Scale
Authors: Ryo Saito, Satoshi Shirai

A supersymmetric standard model with heavier scalar particles is very interesting from various viewpoints, especially Higgs properties. If the scalar mass scale is O(10-10³) TeV, the standard model-like Higgs with mass around 125 GeV, which is implied by the recent LHC experiments, is predicted. However this scenario is very difficult to be directly tested with collider experiments. In this paper, we propose a test of this scenario by using the gravitational wave (GW) experiments as DECIGO and BBO. The future GW experiments can probe the scalar mass around O(10²-10³) TeV, which is preferred from the Higgs mass about 125 GeV.

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Blobrana


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Title: Higgs and Supersymmetry
Authors: O. Buchmueller, R. Cavanaugh, A. De Roeck, M. J. Dolan, J. R. Ellis, H. Flacher, S. Heinemeyer, G. Isidori, J. Marrouche, D. Martinez Santos, K. A. Olive, S. Rogerson, F. J. Ronga, K. J. de Vries, G. Weiglein

Global frequentist fits to the CMSSM and NUHM1 using the MasterCode framework predicted m_h \simeq 119 GeV in fits incorporating the g_mu-2 constraint and \simeq 126 GeV without it. Recent results by ATLAS and CMS could be compatible with a Standard Model-like Higgs boson around m_h \simeq 125 GeV. We use the previous MasterCode analysis to calculate the likelihood for a measurement of any nominal Higgs mass within the range of 115 to 130 GeV. Assuming a Higgs mass measurement at m_h \simeq 125 GeV, we display updated global likelihood contours in the (m_0, m_{1/2}) and other parameter planes of the CMSSM and NUHM1, and present updated likelihood functions for m_gluino, m_squark, B to mu mu, and the spin-independent dark matter cross section \sigma^si. The implications of dropping g_mu-2 from the fits are also discussed. We furthermore comment on a hypothetical measurement of m_h \simeq 119 GeV.

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Blobrana


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Title: Naturalness, Supersymmetry and Implications for LHC and Dark Matter
Authors: Sujeet Akula, Mengxi Liu, Pran Nath, Gregory Peim

It is shown that the Hyperbolic Branch of the radiative electroweak symmetry breaking contains in it three regions: the Focal Point, Focal Curves, and Focal Surfaces. Further, the Focal Point is shown to lie on the boundary of a Focal Curve. These focal regions allow for a small \mu while scalar masses can become large and may lie in the several TeV region. It is shown that for the mSUGRA model the current LHC-7 constraint depletes the Focal Point region while regions on Focal Curves and Focal Surfaces remain largely intact. The LHC implications for models which lie on Focal Curves are briefly discussed as well as the implications of dark matter constraints for the Focal Point, Focal Curves and Focal Surfaces are discussed.

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Blobrana


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Posts: 131433
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Icosahedral symmetry
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Title: Binary Icosahedral Flavour Symmetry for Four Generations of Quarks and Leptons
Authors: Chian-Shu Chen, Thomas W. Kephart, Tzu-Chiang Yuan

To include the quark sector, the A_{5}\equiv I (icosahedron) four generation lepton model is extended to a binary icosahedral symmetry I' flavour model. We find the masses of fermions, including the heavy sectors, can be accommodated. At leading order the CKM matrix is the identity and the PMNS matrix, resulting from same set of vacua, corresponds to tribimaximal mixings.

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Blobrana


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RE: Supersymmetry
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Title: Constraints from the decay B_s -> mu mu and LHC limits on Supersymmetry
Authors: C. Beskidt (1), W. de Boer (1), D.I. Kazakov (2), F. Ratnikov (1), E. Ziebarth (1), V. Zhukov (1) ((1) Karlsruhe Institute of Technology (IEKP), (2) JINR, ITEP, Moscow)

The pure leptonic decay B_s -> mu mu is strongly suppressed in the Standard Model (SM), but can have large enhancements in Supersymmetry, especially at large values of tanbe. New limits on this decay channel from recent LHC data have been used to claim that these limits restrict the SUSY parameter space even more than the direct searches. However, direct searches are hardly dependent on tanbe, while BR(B_s -> mu mu) is proportional to tanbe^6. In order to compare the limits from direct SUSY searches, Higgs searches and B_s -> mu mu one needs to fix tanbe. This can be done by fitting additionally the relic density, which requires large tanbe in a large region of parameter space. We show that the experimental upper limit on BR(B_s -> mu mu) is not constraining the parameter space of the CMSSM, but that the direct searches and the present Higgs limits are the most constraining, if combined with cosmology. In addition, we point out regions where the SUSY expectation is well below the SM expectation, even for large values of tanbe. The expected B_s -> mu mu constraints, if the limits approach the SM within a factor of two, which is expected in the near future, are also shown.

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Blobrana


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N = 2 supersymmetric gauge theory
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Title: Discrete symmetry in supersymmetric N=2 gauge theory
Authors: Michael Kuchiev

A new discrete symmetry group, which governs low-energy properties of the supersymmetric N=2 gauge theory is found. Each element of this group S_r, r being the rank of the gauge group, represents a permutation of r electric charges available in the theory accompanied by a simultaneous permutation of r monopoles, provided the sets of charges and monopoles are chosen properly. Properties of the theory are strongly influenced by S_r; if the central charges (and masses) of r monopoles are degenerate, then the central charges (and masses) of r electric charges are also necessarily degenerate, and vice versa. This condition uniquely defines the vital value of the VEV of the scalar field, at which all monopoles are massless. The general theoretical discussion is illustrated by a model, which generalises the Seiberg-Witten treatment of the supersymmetric N=2 gauge theory for an arbitrary gauge group.

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Blobrana


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RE: Supersymmetry
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Title: Signatures of Supersymmetry from the Early Universe
Authors: Daniel Baumann, Daniel Green

Supersymmetry plays a fundamental role in the radiative stability of many inflationary models. Spontaneous breaking of the symmetry inevitably leads to fields with masses of order the Hubble scale during inflation. When these fields couple to the inflaton they produce a unique signature in the squeezed limit of the three-point function of primordial curvature perturbations. In this paper, we make this connection between naturalness, supersymmetry, Hubble-mass degrees of freedom and the squeezed limit precise. To study the physics in a model-insensitive way, we develop a supersymmetric effective theory of inflation. We use the effective theory to classify all possible interactions between the inflaton and the additional fields, and determine which ones naturally allow large non-Gaussianities when protected by supersymmetry. Finally, we discuss the tantalizing prospect of using cosmological observations as a probe of supersymmetry.

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Blobrana


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LHC results put supersymmetry theory 'on the spot'

Results from the Large Hadron Collider (LHC) have all but killed the simplest version of an enticing theory of sub-atomic physics.
Researchers failed to find evidence of so-called "supersymmetric" particles, which many physicists had hoped would plug holes in the current theory.
Theorists working in the field have told BBC News that they may have to come up with a completely new idea.
Data were presented at the Lepton Photon science meeting in Mumbai.
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