Scalar diquark in top-antitop production and constraints on Yukawa sector of grand unified theories

International audienceA colored weak singlet scalar state with hypercharge 4/3 is one of the possible candidates for the explanation of the unexpectedly large forward-backward asymmetry in tt production as measured by the CDF and D0 experiments. We investigate the role of this state in a plethora of flavor chang- ing neutral current processes and precision observables of down-quarks and charged leptons. Our analysis includes tree- and loop-level mediated observables in the K and B systems, the charged lepton sector, as well as the Z → b ¯b width. We perform a fit of the relevant scalar couplings. This approach can explain the (g − 2)µ anomaly while tensions among the CP violating observables in the quark sector, most notably the nonstandard CP phase (and width difference) in the Bs system cannot be fully relaxed. The results are interpreted in a class of GUT models which allow for a light colored scalar with a mass below 1 TeV

Limits on scalar leptoquark interactions and consequences for GUTs

A colored weak singlet scalar state with hypercharge 4/3 is one of the possible candidates for the explanation of the unexpectedly large forward-backward asymmetry in t tbar production as measured by the CDF and D0 experiments. We investigate the role of this state in a plethora of flavor changing neutral current processes and precision observables of down-quarks and charged leptons. Our analysis includes tree- and loop-level mediated observables in the K and B systems, the charged lepton sector, as well as the Z to b bbar decay width. We perform a global fit of the relevant scalar couplings. This approach can explain the (g-2)_mu anomaly while tensions among the CP violating observables in the quark sector, most notably the nonstandard CP phase (and width difference) in the Bs system cannot be fully relaxed. The results are interpreted in a class of grand unified models which allow for a light colored scalar with a mass below 1TeV. We find that the renormalizable SU(5) scenario is not compatible with our global fit, while in the SO(10) case the viability requires the presence of both the 126- and 120-dimensional representations.Comment: 26 pages, 7 figures; version as publishe

Of linkers and autochaperones: an unambiguous nomenclature to identify common and uncommon themes for autotransporter secretion.

Autotransporter (AT) proteins provide a diverse array of important virulence functions to Gram-negative bacterial pathogens, and have also been adapted for protein surface display applications. The 'autotransporter' moniker refers to early models that depicted these proteins facilitating their own translocation across the bacterial outer membrane. Although translocation is less autonomous than originally proposed, AT protein segments upstream of the C-terminal transmembrane β-barrel have nevertheless consistently been found to contribute to efficient translocation and/or folding of the N-terminal virulence region (the 'passenger'). However, defining the precise secretion functions of these AT regions has been complicated by the use of multiple overlapping and ambiguous terms to define AT sequence, structural, and functional features, including 'autochaperone', 'linker' and 'junction'. Moreover, the precise definitions and boundaries of these features vary among ATs and even among research groups, leading to an overall murky picture of the contributions of specific features to translocation. Here we propose a unified, unambiguous nomenclature for AT structural, functional and conserved sequence features, based on explicit criteria. Applied to 16 well-studied AT proteins, this nomenclature reveals new commonalities for translocation but also highlights that the autochaperone function is less closely associated with a conserved sequence element than previously believed

Design of coiled-coil protein-origami cages that self-assemble in vitro and in vivo

Polypeptides and polynucleotides are natural programmable biopolymers that can self-assemble into complex tertiary structures. We describe a system analogous to designed DNA nanostructures in which protein coiled-coil (CC) dimers serve as building blocks for modular de novo design of polyhedral protein cages that efficiently self-assemble in vitro and in vivo. We produced and characterized gt 20 single-chain protein cages in three shapes-tetrahedron, four-sided pyramid, and triangular prism-with the largest containing gt 700 amino-acid residues and measuring 11 nm in diameter. Their stability and folding kinetics were similar to those of natural proteins. Solution small-angle X-ray scattering (SAXS), electron microscopy (EM), and biophysical analysis confirmed agreement of the expressed structures with the designs. We also demonstrated self-assembly of a tetrahedral structure in bacteria, mammalian cells, and mice without evidence of inflammation. A semi-automated computational design platform and a toolbox of CC building modules are provided to enable the design of protein cages in any polyhedral shape.Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3212

Probing anomalous tq and tqg couplings via single top production in association with photon at FCC-hh

Senol, Abdulkadir/0000-0001-8782-4608; Yilmaz, Ali/0000-0001-5963-8306; CAKIR, Orhan/0000-0002-9016-138X; denizli, haluk/0000-0003-1570-0344; Oyulmaz, Kaan Yuksel/0000-0002-5533-9621WOS: 000457233200005We study the anomalous FCNC tq and tqg couplings via ppWb+X signal process including realistic detector effects for both leptonic and hadronic decay channels of the W boson at 100 TeV FCC-hh. The relevant backgrounds are considered in the cut based analysis to obtain not only limits on the anomalous and couplings but also branching ratios of tq and tqg decay channels. We find that the sensitivity to the branching ratio of tq channel is three order better than the available LHC experimental limits, and it is comparable for the branching ratio of the tqg decay channel with an integrated luminosity of 10 ab-1 at 2 sigma significance level.Turkish Atomic Energy Authority (TAEK)Ministry of Energy & Natural Resources - Turkey [2018TAEK(CERN)A5.H6.F2-20]; Bolu Abant Izzet Baysal University Scientific Research Projects [2018.03.02.1286]This work was supported by Turkish Atomic Energy Authority (TAEK) under the Grant No. 2018TAEK(CERN)A5.H6.F2-20. We acknowledge exciting discussion within the FCC-hh physics analysis meeting. The K.Y. O., A. S. and H. D. work partially supported by the Bolu Abant Izzet Baysal University Scientific Research Projects under the Project No: 2018.03.02.1286