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Virtual effects of split-SUSY in Higgs productions at linear colliders

Wang, Fei; Wang, Wenyu; Xu, Fuqiang; Yang, Jin Min; Zhang, HuanjunSubjects: Physics >> The Physics of Elementary Particles and Fields

In split supersymmetry, gauginos and higgsinos are the only supersymmetric particles possibly accessible at foreseeable colliders like the CERN Large Hadron Collider (LHC) and the International Linear Collider (ILC). In order to account for the cosmic dark matter measured by WMAP, these gauginos and higgsinos are stringently constrained and could be explored at the colliders through their direct productions and/or virtual effects in some processes. The clean environment and high luminosity of the ILC render the virtual effects at percent level meaningful in unraveling the new physics effects. In this work we assume split supersymmetry and calculate the virtual effects of the WMAP-allowed gauginos and higgsinos in the Higgs productions e(+) e(-) -> Zh and e(+) e(-) ->nu(e)(nu) over bar (e)h through WW fusion at the ILC. We find that the production cross section of e+ e-. Zh can be altered by a few percent in some part of the WMAP-allowed parameter space, while the correction to the WW fusion process e(+) e(-) ->nu(e) (nu) over bar (e)h is below 1%. Such virtual effects are correlated with the cross sections of chargino pair productions and can offer complementary information in probing split supersymmetry at the colliders. |

Realistic flipped SU(5) from orbifold SO(10)

Balazs, Csaba; Kang, Zhaofeng; Li, Tianjun; Wang, Fei; Yang, Jin MinSubjects: Physics >> The Physics of Elementary Particles and Fields

We propose a realistic flipped SU(5) model derived from a five-dimensional orbifold SO(10) model. The Standard Model (SM) fermion masses and mixings are explained by combining the traditional Froggatt-Nielsen mechanism with the five-dimensional wave function profiles of the SM fermions. Employing tree-level spontaneous R-symmetry breaking in the hidden sector and extra( ordinary) gauge mediation, we obtain realistic supersymmetry breaking soft mass terms with non-vanishing gaugino masses. Including the messenger fields at the intermediate scale and Kaluza-Klein states at the compactification scale, we study gauge coupling unification. We show that the SO(10) unified gauge coupling is very strong and the unification scale can be much higher than the compactification scale. We briefly discuss proton decay as well. |

Low-scale SU(4)(W) unification

Balazs, Csaba; Li, Tianjun; Wang, Fei; Yang, Jin MinSubjects: Physics >> The Physics of Elementary Particles and Fields

We embed the minimal left-right model SU(2) L x SU(2) R x U(1)B-L into an SU(4) W gauge group, and break the unified group via five-dimensional S-1/(Z(2) x Z2) orbifolding. Leptons are fitted into SU(4)(W) multiplets and located on a symmetry preserving O brane, while quarks are placed onto an O' brane where the symmetry is broken. This approach predicts sin(2) theta(W) = 0.25 for the weak mixing angle at tree level and leads to a rather low weakly ( strongly) coupled unification scale of order 3 x 10(2) TeV (several TeV) with supersymmetry, or as low as several TeV in the non-supersymmetric case. Another symmetry breaking chain with the low-energy gauge group SU(2)(L) x U(1)(3R) x U(1)(B-L) can also give rise to a weak mixing angle sin 2. W = 0.25 at tree level after gauge symmetry breaking by orbifolding. Such theories with low-scale unification have interesting phenomenological consequences. |

The SU(3)(C) x SU(4)(W) x U(1)B-L models with left-right unification

Li, Tianjun; Wang, Fei; Yang, Jin MinSubjects: Physics >> The Physics of Elementary Particles and Fields

To understand the origin of the left-right symmetry, we study a partial unification model based on SU(4)(W) x U(1)(B-L) which can be broken down to the mini mal left-right model either through the Higgs mechanism in four dimensions or through the five-dimensional orbifolding gauge symmetry breaking, especially we propose to use the rank reducing outer automorphism orbifolding breaking mechanism. We scrutinized all these breaking mechanisms and found that for the orbifold breaking in five dimensions, the rank-reducing outer automorphism is better than the inner automorphism and can make the low energy theory free of the U(1)Z anomaly. It is possible for the outer automorphism orbifolding breaking mechanism to be non-anomalous without Chern-Simons terms and new localized fermions. For the four-dimensional model with the Higgs mechanism, we study in detail both its structure and its typical phenomenology. It turns out that this four-dimensional scenario may predict some new phenomenology since the new mirror fermions (which are introduced in order to fill the SM fermions into SU(4)W without anomaly) are preserved at low energy scale and mix with the SM fermions. We also examine the gauge coupling unification in each case, and discuss the possibility for unifying this partial unification group with the Pati-Salam group SU(4)(PS) to realize a grand unification. (C) 2009 Elsevier B.V. All rights reserved. |

Subjects: Biology >> Biophysics >> Biology

B lymphocytes use B cell receptors (BCRs) to sense the physical features of the antigens. However, the sensitivity and threshold for the activation of BCRs resulting from the stimulation by mechanical forces are unknown. Here, we addressed this question using a double-stranded DNA-based tension gauge tether system serving as a predefined mechanical force gauge ranging from 12 to 56 pN. We observed that IgM-BCR activation is dependent on mechanical forces and exhibits a multi-threshold effect. In contrast, the activation of isotype-switched IgG- or IgE-BCR only requires a low threshold of less than 12 pN, providing an explanation for their rapid activation in response to antigen stimulation. Mechanistically, we found that the cytoplasmic tail of the IgG-BCR heavy chain is both required and sufficient to account for the low mechanical force threshold. These results defined the mechanical force sensitivity and threshold that are required to activate different isotyped BCRs. |

Top and bottom seesaw from supersymmetric strong dynamics

Balazs, Csaba; Li, Tianjun; Wang, Fei; Yang, Jin MinSubjects: Physics >> The Physics of Elementary Particles and Fields

We propose a top and bottom seesaw model with partial composite top and bottom quarks. Such composite quarks and topcolor gauge bosons are bound states from supersymmetric strong dynamics by Seiberg duality. Supersymmetry breaking also induces the breaking of topcolor into the QCD gauge coupling. The low energy description of our model reduces to a complete non-minimal extension of the top seesaw model with bottom seesaw. The non-minimal nature is crucial for Higgs mixings and the appearance of light Higgs fields. The Higgs fields are bound states of partial composite particles with the lightest one compatible with a 125 GeV Higgs field which was discovered at the LHC. |

CD163+CD14+macrophages, a potential immune biomarker for malignant pleural effusion

Wang, Fei; Yang, Li; Gao, Qun; Huang, Lan; Zhang, Yi; Wang, Fei; Zhang, Yi; Gao, Qun; Wang, Liping; Zhang, Yi; Wang, Jing; Wang, Shengdian; Zhang, BinSubjects: Biology >> Biophysics >> Oncology

Malignant pleural effusion (MPE) is a common complication caused by malignant diseases. However, subjectivity, poor sensitivity, and substantial false-negative rates of cytology assay hamper accurate MPE diagnosis. The aim of this study was to assess whether CD163+CD14+ tumor-associated macrophages (TAMs) could be used as a biomarker for enabling sensitive and specific MPE diagnosis. Pleural effusion samples and peripheral blood samples were collected from 50 MPE patients and 50 non-malignant pleural effusion (NMPE) patients, respectively. Flow cytometry was performed to analyze cell phenotypes, and RT-qPCR was used to detect cytokine expression in these monocytes and macrophages. A blinded validation study (n = 40) was subsequently performed to confirm the significance of CD163+CD14+ TAMs in MPE diagnosis. Student's t test, rank sum test, and receiver operating characteristic curve analysis were used for statistical analysis. Notably, CD163+CD14+ cell frequency in MPE was remarkably higher than that in NMPE (P < 0.001). In a blinded validation study, a sensitivity of 78.9 % and a specificity of 100 % were obtained with CD163+CD14+ TAMs as a MPE biomarker. In total (n = 140), by using a cutoff level of 3.65 %, CD163+CD14+ cells had a sensitivity of 81.2 % and a specificity of 100 % for MPE diagnosis. Notably, MPE diagnosis by estimating CD163+CD14+ cells in pleural effusion could be obtained one week earlier than that obtained by cytological examination. CD163+CD14+ macrophages could be potentially used as an immune diagnostic marker for MPE and has better assay sensitivity than that of cytological analysis. |

Singlet extension of the MSSM as a solution to the small cosmological scale anomalies

Wang, Fei; Wang, Wenyu; Yang, Jin Min; Zhou, SihongSubjects: Physics >> The Physics of Elementary Particles and Fields

In this work we show that the general singlet extension of the minimal supersymmetric standard model (MSSM) can naturally provide a self-interacting singlino dark matter to solve the small cosmological scale anomalies (a large Sommerfeld enhancement factor can also be obtained). However, we find that the NMSSM (the singlet extension of the MSSM with Z(3) symmetry) cannot achieve this due to the restricted parameter space. In our analysis we introduce the concept of symmetric and antisymmetric viscosity cross sections to deal with the nonrelativistic Majorana-fermion dark matter scattering. |

Split supersymmetry under GUT and current dark matter constraints

Wang, Fei; Wang, Wenyu; Yang, Jin MinSubjects: Physics >> The Physics of Elementary Particles and Fields

We recalculate the two-loop beta functions for three gauge couplings taking into account all low energy threshold corrections in split supersymmetry(split-SUSY) which assumes a very high scalar mass scale M-S. We find that in split-SUSY with a gaugino mass unification assumption and with a large M-S the gauge coupling unification requires a lower bound on the gaugino mass. Combined with the constraints from the dark matter relic density and direct detection limits, we find that split-SUSY is very restricted and for dark matter mass below 1 TeV the allowed parameter space can be fully covered by XENON-1T(2017). |

A split SUSY model from SUSY GUT

Wang, Fei; Wang, Wenyu; Yang, Jin MinSubjects: Physics >> The Physics of Elementary Particles and Fields

We propose to split the sparticle spectrum from the hierarchy between the GUT scale and the Planck scale. A split supersymmetric model, which gives non-universal gaugino masses, is built with proper high dimensional operators in the framework of SO(10) GUT. Based on a calculation of two-loop beta functions for gauge couplings (taking into account all weak scale threshold corrections), we check the gauge coupling unification and dark matter constraints (relic density and direct detections). We find that our scenario can achieve the gauge coupling unification and satisfy the dark matter constraints in some part of parameter space. We also examine the sensitivity of the future XENON1T experiment and find that the currently allowed parameter space in our scenario can be covered for a neutralino dark matter below about 1.0 TeV. |