116 research outputs found

    The Universal One-Loop Effective Action

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    We present the universal one-loop effective action for all operators of dimension up to six obtained by integrating out massive, non-degenerate multiplets. Our general expression may be applied to loops of heavy fermions or bosons, and has been checked against partial results available in the literature. The broad applicability of this approach simplifies one-loop matching from an ultraviolet model to a lower-energy effective field theory (EFT), a procedure which is now reduced to the evaluation of a combination of matrices in our universal expression, without any loop integrals to evaluate. We illustrate the relationship of our results to the Standard Model (SM) EFT, using as an example the supersymmetric stop and sbottom squark Lagrangian and extracting from our universal expression the Wilson coefficients of dimension-six operators composed of SM fields.Comment: 30 pages, v2 contains additional comments and corrects typos, version accepted for publication in JHE

    Implications of a High-Mass Diphoton Resonance for Heavy Quark Searches

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    Heavy vector-like quarks coupled to a scalar SS will induce a coupling of this scalar to gluons and possibly (if electrically charged) photons. The decay of the heavy quark into SqSq, with qq being a Standard Model quark, provides, if kinematically allowed, new channels for heavy quark searches. Inspired by naturalness considerations, we consider the case of a vector-like partner of the top quark. For illustration, we show that a singlet partner can be searched for at the 13\,TeV LHC through its decay into a scalar resonance in the 2γ++X2\gamma+\ell + X final states, especially if the diphoton branching ratio of the scalar SS is further enhanced by the contribution of non coloured particles. We then show that conventional heavy quark searches are also sensitive to this new decay mode, when SS decays hadronically, by slightly tightening the current selection cuts. Finally, we comment about the possibility of disentangling, by scrutinising appropriate kinematic distributions, heavy quark decays to StSt from other standard decay modes.Comment: 8 pages, 3 figures and 1 table; v3: typos fixed. Matches published versio

    A fluorescent hormone biosensor reveals the dynamics of jasmonate signalling in plants

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    Activated forms of jasmonic acid (JA) are central signals coordinating plant responses to stresses, yet tools to analyse their spatial and temporal distribution are lacking. Here we describe a JA perception biosensor termed Jas9-VENUS that allows the quantification of dynamic changes in JA distribution in response to stress with high spatiotemporal sensitivity. We show that Jas9-VENUS abundance is dependent on bioactive JA isoforms, the COI1 co-receptor, a functional Jas motif and proteasome activity. We demonstrate the utility of Jas9-VENUS to analyse responses to JA in planta at a cellular scale, both quantitatively and dynamically. This included using Jas9-VENUS to determine the cotyledon-to-root JA signal velocities on wounding, revealing two distinct phases of JA activity in the root. Our results demonstrate the value of developing quantitative sensors such as Jas9-VENUS to provide high-resolution spatiotemporal data about hormone distribution in response to plant abiotic and biotic stresses

    Novel signatures for vector-like quarks

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    We consider supersymmetric extensions of the standard model with a vector-like doublet (T B) of quarks with charge 2/3 and −1/3, respectively. Compared to non-supersymmetric models, there is a variety of new decay modes for the vector-like quarks, involving the extra scalars present in supersymmetry. The importance of these new modes, yielding multi-top, multi-bottom and also multi-Higgs signals, is highlighted by the analysis of several benchmark scenarios. We show how the triangles commonly used to represent the branching ratios of the ‘standard’ decay modes of the vector-like quarks involving W, Z or Higgs bosons can be generalised to include additional channels. We give an example by recasting the limits of a recent heavy quark search for this more general case.The work of J.A. Aguilar-Saavedra has been supported by MINECO Projects FPA 2016- 78220-C3-1-P and FPA 2013-47836-C3-2-P (including ERDF), and by Junta de Andaluc a Project FQM-101. The work of D.E. L opez-Fogliani has been supported by the Argentinian CONICET. The work of C. Mu~noz has been supported in part by the Programme SEV- 2012-0249 `Centro de Excelencia Severo Ochoa'. D.E. L opez-Fogliani and C. Mu~noz also acknowledge the support of the Spanish grant FPA2015-65929-P (MINECO/FEDER, UE), and MINECO's Consolider-Ingenio 2010 Programme under grant MultiDark CSD2009- 00064

    Culture-independent molecular analysis of bacterial diversity in uranium-ore/-mine waste-contaminated and non-contaminated sites from uranium mines

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    Soil, water and sediment samples collected from in and around Jaduguda, Bagjata and Turamdih mines were analyzed for physicochemical parameters and cultured, and yet to be cultured microbial diversity. Culturable fraction of microbial community measured as Colony Forming Unit (CFU) on R2A medium revealed microbes between 104 and 109 CFU/g sample. Community DNA was extracted from all the samples; 16S rRNA gene amplified, cloned and subject to Amplified Ribosomal DNA Restriction Analysis. Clones representing each OTU were selected and sequenced. Sequence analyses revealed that non-contaminated samples were mostly represented by Acidobacteria, Bacteroidetes, Firmicutes and Proteobacteria (β-, γ-, and/or δ-subdivisions) along with less frequent phyla Nitrospira, Deferribacteres, Chloroflexi. In contrast, samples obtained from highly contaminated samples showed distinct abundance of β-,γ- and α-Proteobacteria along with Acidobacteria,Bacteroidetes and members of Firmicutes, Chloroflexi, Candidate division, Planctomycete, Cyanobacteria and Actinobacteria as minor groups. Our data represented the baseline information on bacterial community composition within non-contaminated samples which could potentially be useful for assessing the impact of metal and radionuclides contamination due to uranium mine activities

    Effective description of general extensions of the Standard Model: the complete tree-level dictionary

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    We thank Nuria Rius and Arcadi Santamaria for an interesting discussion that motivated this work. We also thank Paco del Águila and Toni Pich for useful comments.We compute all the tree-level contributions to the Wilson coefficients of the dimension-six Standard-Model effective theory in ultraviolet completions with general scalar, spinor and vector feld content and arbitrary interactions. No assumption about the renormalizability of the high-energy theory is made. This provides a complete ultraviolet/ infrared dictionary at the classical level, which can be used to study the low-energy implications of any model of interest, and also to look for explicit completions consistent with low-energy dataThe work of J.C.C., M.P.V. and J.S. has been supported by the Spanish MICINN project FPA2013- 47836-C3-2-P, the MINECO project FPA2016-78220-C3-1-P (Fondos FEDER) and the Junta de Andalucía grant FQM101. The work of J.C.C. has also been supported by the Spanish MECD grant FPU14. The work of M.P.V. and J.S. has also been supported by the European Commission through the contract PITN-GA-2012-316704 (HIGGSTOOLS). J.C.C. is grateful for the hospitality of the Dipartimento di Fisica e Astronomia \Galileo Galilei" of the University of Padova during part of this work. J.S. would like to thank the Mainz Institute for Theoretical Physics (MITP) for its hospitality and partial support during the completion of this work
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