Showing papers on "Naturalness published in 2012"
02 Jun 2012
TL;DR: The conjecture that most software is also natural, in the sense that it is created by humans at work, with all the attendant constraints and limitations, and thus, like natural language, it is also likely to be repetitive and predictable is conjecture.
Abstract: Natural languages like English are rich, complex, and powerful. The highly creative and graceful use of languages like English and Tamil, by masters like Shakespeare and Avvaiyar, can certainly delight and inspire. But in practice, given cognitive constraints and the exigencies of daily life, most human utterances are far simpler and much more repetitive and predictable. In fact, these utterances can be very usefully modeled using modern statistical methods. This fact has led to the phenomenal success of statistical approaches to speech recognition, natural language translation, question-answering, and text mining and comprehension. We begin with the conjecture that most software is also natural, in the sense that it is created by humans at work, with all the attendant constraints and limitations — and thus, like natural language, it is also likely to be repetitive and predictable. We then proceed to ask whether a) code can be usefully modeled by statistical language models and b) such models can be leveraged to support software engineers. Using the widely adopted n-gram model, we provide empirical evidence supportive of a positive answer to both these questions. We show that code is also very repetitive, and in fact even more so than natural languages. As an example use of the model, we have developed a simple code completion engine for Java that, despite its simplicity, already improves Eclipse's built-in completion capability. We conclude the paper by laying out a vision for future research in this area.
642 citations
TL;DR: In this paper, a supersymmetric effective theory of inflation was developed 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.
Abstract: 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.
378 citations
TL;DR: In this article, the authors consider the renormalization group improvement in the theory of the Standard Model (SM) Higgs boson playing the role of an inflaton with a strong non-minimal coupling to gravity.
Abstract: We consider the renormalization group improvement in the theory of the Standard Model (SM) Higgs boson playing the role of an inflaton with a strong non-minimal coupling to gravity. At the one-loop level with the running of constants taken into account, it leads to a range of the Higgs mass that is entirely determined by the lower WMAP bound on the cosmic microwave background (CMB) spectral index. We find that the SM phenomenology is sensitive to current cosmological data, which suggests to perform more precise CMB measurements as a SM test complementary to the LHC program. By using the concept of a field-dependent cutoff, we show the naturalness of the gradient and curvature expansion in this model within the conventional perturbation theory range of the SM. We also discuss the relation of these results to two-loop calculations and the limitations of the latter caused by parametrization and gauge dependence problems.
201 citations
TL;DR: In this paper, a bottom-up approach was taken to evaluate the naturalness of the Higgs boson mass in both the MSSM and NMSSM models, and it was shown that naturalness will favor the NMSSMs.
Abstract: With a bottom-up approach, we consider naturalness in the MSSM and NMSSM. Assuming the light stops, the LHC gluino search implies that the degree of fine tuning in both models is less than 2.5%. Taking the LHC hints for the SM-like Higgs boson mass m_h\sim125 GeV seriously, we find that naturalness will favor the NMSSM. We study the Higgs boson mass for several scenarios in the NMSSM: (1) A large \lambda and the doublet-singlet Higgs boson mixing effect pushing upward or pulling downward m_h. The former case can readily give the di-photon excess of the Higgs boson decay whereas the latter case can not. However, we point out that the former case has a new large fine-tuning related to strong \lambda-RGE running effect and vacuum stability. (2) A small \lambda and the mixing effect pushing m_h upward. Naturalness status becomes worse and no significant di-photon excess can be obtained. In these scenarios, the lightest supersymmetric particle (LSP) as a dark matter candidate is strongly disfavored by the XENON100 experiment. Even if the LSP can be a viable dark matter candidate, there does exist fine-tuning. The above naturalness evaluation is based on a high mediation scale for supersymmetry breaking, whereas for a low mediation scale, fine-tuning can be improved by about one order.
127 citations
TL;DR: A review of the literature on forest naturalness suggests four main reasons for the lack of a widely accepted approach for assessing naturalness: (1) the absence of a commonly accepted reference concept, (2) an incomplete list of essential naturalness traits, (3) unknown linkages between some naturalness attributes and biodiversity, and (4) the inability of an assessment approach that can be adapted for use at both regional and large scales as discussed by the authors.
Abstract: Summary A primary prerequisite for the preservation of global diversity is often assumed to be a high level of naturalness. This paper reports a synthesis of naturalness definitions, distinctions between the concepts of naturalness and of hemeroby and an analysis of different naturalness assessment approaches. Naturalness may be commonly defined as ‘the similarity of a current ecosystem state to its natural state’. Hemeroby, a concept related to human impacts, is often associated with naturalness but, in principle, the two concepts are not inversely related. The hemeroby concept defines narrow assessment classes for greater hemeroby, whereas the naturalness concept defines narrow assessment classes for great naturalness. The rapidly increasing number of forest naturalness papers relies on the following main indicators in decreasing order of use: tree species, forest structure, fauna, ground vegetation and deadwood. A review of the literature on forest naturalness suggests four main reasons for the lack of a widely accepted approach for assessing naturalness: (1) the lack of a commonly accepted reference concept, (2) an incomplete list of essential naturalness traits, (3) unknown linkages between some naturalness traits and biodiversity and (4) the lack of an assessment approach that can be adapted for use at both regional and large scales. Following review of the literature on forest naturalness, a seven-level framework is presented to guide development of naturalness assessment approaches as a component of forest biodiversity monitoring and conservation management.
115 citations
TL;DR: In this paper, a bottom-up approach was taken to evaluate the naturalness of the Higgs boson mass in the MSSM and NMSSM, and it was shown that naturalness will favor the NMSSMs. Assuming the light stops the LHC gluino search implies that the degree of fine tuning in both models is less than 25%.
Abstract: With a bottom-up approach, we consider naturalness in the MSSM and NMSSM Assuming the light stops the LHC gluino search implies that the degree of fine tuning in both models is less than 25% Taking the LHC hints for the SM-like Higgs boson mass m(h) similar to 125 GeV seriously, we find that naturalness will favor the NMSSM We study the Higgs boson mass for several scenarios in the NMSSM: (1) A large A and the doublet-singlet Higgs boson mixing effect pushing upward or pulling downward nth The former case can readily give the di-photon excess of the Higgs boson decay whereas the latter case can not However, we point out that the former case has a new large fine-tuning related to strong A ROE running effect and vacuum stability (2) A small A and the mixing effect pushing m(h) upward Naturalness status becomes worse and no significant di-photon excess can be obtained In these scenarios, the lightest supersymmetric particle (LSP) as a dark matter candidate is strongly disfavored by the XENON100 experiment Even if the LSP can be a viable dark matter candidate, there does exist fine-tuning The above naturalness evaluation is based on a high mediation scale for supersymmetry breaking, whereas for a low mediation scale, fine-tuning can be improved by about one order
109 citations
TL;DR: In this paper, the authors revisited the problem from the viewpoint of the Wilsonian renormalization group and argued that quadratic divergences should always be absorbed into a position of the critical surface.
Abstract: It is widely believed that quadratic divergences severely restrict natural constructions of particle physics models beyond the standard model (SM). Supersymmetry provides a beautiful solution, but the recent LHC experiments have excluded large parameter regions of supersymmetric extensions of the SM. It will now be important to reconsider whether we have been misinterpreting the quadratic divergences in field theories. In this paper, we revisit the problem from the viewpoint of the Wilsonian renormalization group and argue that quadratic divergences---which can always be absorbed into a position of the critical surface---should be simply subtracted in model constructions. Such a picture gives another justification to the argument [W. A. Bardeen, Report No. FERMILAB-CONF-95-391-T] that the scale invariance of the SM, except for the soft-breaking terms, is an alternative solution to the naturalness problem. It also largely broadens possibilities of model constructions beyond the SM since we just need to take care of logarithmic divergences, which cause mixings of various physical scales and runnings of couplings.
84 citations
TL;DR: Laughter positively predicted happiness in all but one of the communication modes, with real and symbolic laughter having similar effects, a result consistent with the social information processing theory.
Abstract: Media naturalness theory and social information processing theory make competing predictions regarding the effectiveness of different modes of communication at creating and maintaining emotionally intense social relationships. We explored how the duration of interaction and the form of laughter influenced happiness in communication modes with different levels of media naturalness. Forty-one participants completed a 14-day contact diary, recording interactions across face-to-face, Skype, telephone, instant messaging, texting, and e-mail/social network sites. Increases in duration of interaction positively predicted happiness only for face-to-face interactions, offering partial support for the media naturalness hypothesis. Laughter positively predicted happiness in all but one of the communication modes, with real and symbolic laughter having similar effects, a result consistent with the social information processing theory. © 2012 Wiley Periodicals, Inc.
80 citations
TL;DR: In this paper, a generic signature in the form of same-sign, flavour-ambivalent leptons, without large missing transverse momentum signatures, was proposed for supersymmetric solutions of the naturalness problem.
Abstract: Gluinos that result in classic large missing transverse momentum signatures at the LHC have been excluded by 2011 searches if they are lighter than around 800 GeV. This adds to the tension between experiment and supersymmetric solutions of the naturalness problem, since the gluino is required to be light if the electroweak scale is to be natural. Here, we examine natural scenarios where supersymmetry is present, but has hidden from 2011 searches due to violation of R-parity and the absence of a large missing transverse momentum signature. Naturalness suggests that third generation states should dominate gluino decays and we argue that this leads to a generic signature in the form of same-sign, flavour-ambivalent leptons, without large missing transverse momentum. As a result, searches in this channel are able to cover a broad range of scenarios with some generality and one should seek gluinos that decay in this way with masses below a TeV. We encourage the LHC experiments to tailor a search for supersymmetry in this form. We consider a specific case that is good at hiding: baryon number violation, and estimate that the most constraining existing search from 2011 data implies a lower bound on the gluino mass of 550 GeV.
80 citations
TL;DR: In this paper, the authors provide a systematic effective lagrangian description of the phenomenology of the lightest top-partners in composite Higgs models, based on symmetry, on selection rules and on plausible dynamical assumptions.
Abstract: We provide a systematic effective lagrangian description of the phenomenology of the lightest top-partners in composite Higgs models. Our construction is based on symmetry, on selection rules and on plausible dynamical assumptions. The structure of the resulting simplified models depends on the quantum numbers of the lightest top partner and of the operators involved in the generation of the top Yukawa. In all cases the phenomenology is conveniently described by a small number of parameters, and the results of experimental searches are readily interpreted as a test of naturalness. We recast presently available experimental bounds on heavy fermions into bounds on top partners: LHC has already stepped well inside the natural region of parameter space.
TL;DR: In this article, a Bayesian formulation of naturalness made in the framework of Bayesian statistics is presented, which unravels the conceptual problems related to previous approaches and shows that the relative interpretation of the measure of Naturalness turns out to be unambiguously established by Jeffreys' scale.
Abstract: We present a formulation of naturalness made in the framework of Bayesian statistics, which unravels the conceptual problems related to previous approaches. Among other things, the relative interpretation of the measure of naturalness turns out to be unambiguously established by Jeffreys' scale. Also, the usual sensitivity formulation (the so-called Barbieri-Giudice measure) appears to be embedded in our formulation under an extended form. We derive the general sensitivity formula applicable to an arbitrary number of observables. Several consequences and developments are further discussed. As a final illustration, we work out the map of combined fine-tuning associated with the gauge hierarchy problem and neutralino dark matter in a classic supersymmetric model.
TL;DR: The authors showed that naturalness preference is largely due to ideational reasons (moral or aesthetic appeals), rather than instrumental reasons (inferred functional superiority), because the natural and unnatural alternatives were specified as identical.
Abstract: Naturalness preference refers to the tendency to prefer natural things to otherwise equivalent unnatural alternatives. Previous research suggests that the naturalness preference is largely due to ideational reasons (moral or aesthetic appeals), rather than instrumental reasons (inferred functional superiority), because the natural and unnatural alternatives were specified as identical. The current studies showed that people do not always believe that natural and unnatural alternatives can be identical. Responses that in previous studies would have been interpreted as ideational-based naturalness preference were correlated with beliefs in instrumental advantages of natural products. We propose that instrumental and ideational reasons are closely connected, and instrumental beliefs may contribute to the “natural is better” heuristic. The financial consequence of naturalness preference was also demonstrated.
TL;DR: An investigation of harmonized approaches to assessing forest naturalness using NFI variables was conducted as a component of a pan-European harmonization project and found that NFI features such as minimum dbh and plot size affect estimates of indicators of naturalness, and accommodation of their differences may be necessary.
Abstract: The concept of naturalness has been proposed and used for describing the ecological value of forest ecosystems, evaluating management efforts to conserve biodiversity, and identifying natural, old-growth forests for purposes of establishing protection areas. Because the concept is not globally familiar, a literature review was conducted to document the ecological basis for the concept. In addition, the necessity for harmonized reporting motivated an investigation of variables that can be used to quantify and assess forest naturalness. National forest inventories (NFIs) are sources of the most comprehensive and extensive data available for assessing naturalness. However, the variety of NFI plot configurations, sampling designs, definitions, and measurement protocols greatly impedes the utility of NFI data for purposes of producing compatible estimates. As a component of a pan-European harmonization project, a three-phase investigation of harmonized approaches to assessing forest naturalness using NFI variables was conducted. Although the project was primarily European in scope, forest inventory data for an American ecoprovince were used because of their availability, comprehensiveness, and consistency. The primary result is that NFI features such as minimum dbh and plot size affect estimates of indicators of naturalness, and accommodation of their differences may be necessary if harmonized estimates of indicators of naturalness across countries are required. FOR .S CI. 58(3):294 -309.
TL;DR: In this paper, a solution of the naturalness problem in the context of the multiverse wave function without the anthropic argument is proposed, where the coupling constants induced by the wormholes are fixed in such a way that the density matrix is maximized.
Abstract: We propose a solution of the naturalness problem in the context of the multiverse wavefunction without the anthropic argument. If we include microscopic wormhole configurations in the path integral, the wave function becomes a superposition of universes with various values of the coupling constants such as the cosmological constant, the parameters in the Higgs potential, and so on. We analyze the quantum state of the multiverse, and evaluate the density matrix of one universe. We show that the coupling constants induced by the wormholes are fixed in such a way that the density matrix is maximized. In particular, the cosmological constant, which is in general time-dependent, is chosen such that it takes an extremely small value in the far future. We also discuss the gauge hierarchy problem and the strong CP problem in this context. Our study predicts that the Higgs mass is mh = 140 ± 20 GeV and θ =0 . Subject Index: 129
[...]
TL;DR: In this article, the authors discuss collider signatures of the "natural supersymmetry" scenario with baryon number violating R-parity violation, and propose novel strategies for distinguishing these signals above background, and estimate their potential reach at the 8 TeV LHC.
Abstract: We discuss collider signatures of the "natural supersymmetry" scenario with baryon-number violating R-parity violation. We argue that this is one of the few remaining viable incarnations of weak scale supersymmetry consistent with full electroweak naturalness. We show that this intriguing and challenging scenario contains distinctive LHC signals, resonances of hard jets in conjunction with relatively soft leptons and missing energy, which are easily overlooked by existing LHC searches. We propose novel strategies for distinguishing these signals above background, and estimate their potential reach at the 8 TeV LHC. We show that other multi-lepton signals of this scenario can be seen by currently existing searches with increased statistics, but these opportunities are more spectrum-dependent.
TL;DR: This paper examined the public debate over marriage law to investigate how arguments based on claims about what is natural privilege some relationships while stigmatizing others and justifying discriminatory policies toward sexual minorities and found that change over time, norms, procreation, and welfare of children were most frequent arguments for same-sex marriage.
Abstract: This article examines the public debate over marriage law to investigate how arguments based on claims about what is natural privilege some relationships while stigmatizing others and justifying discriminatory policies toward sexual minorities. Articles about same-sex marriage appearing in major newspapers were content-coded according to absence or presence of four dimensions of naturalness: change over time, norms, procreation, and welfare of children. Arguments invoking change over time were most frequent (39%), and procreation appeared least (10%). The use of arguments based on the moral status of marriage was associated with the use of each of the four dimensions based on naturalness. Mentions of race, including comparisons to racial struggles, appeared in 20% of the articles, making them just as common as child welfare. Results are discussed in terms of the power of the concept of naturalness to legitimize and maintain privilege, and the intersectionality of race and sexual orientation.
TL;DR: In this paper, the authors provide a systematic effective lagrangian description of the phenomenology of the lightest top-partners in composite Higgs models, based on symmetry, on selection rules and on plausible dynamical assumptions.
Abstract: We provide a systematic effective lagrangian description of the phenomenology of the lightest top-partners in composite Higgs models. Our construction is based on symmetry, on selection rules and on plausible dynamical assumptions. The structure of the resulting simplified models depends on the quantum numbers of the lightest top partner and of the operators involved in the generation of the top Yukawa. In all cases the phenomenology is conveniently described by a small number of parameters, and the results of experimental searches are readily interpreted as a test of naturalness. We recast presently available experimental bounds on heavy fermions into bounds on top partners: LHC has already stepped well inside the natural region of parameter space.
TL;DR: In this paper, a detailed study of a variety of LHC signals in supersymmetric models where lepton number is promoted to an approximate U(1)_R symmetry is performed.
Abstract: We perform a detailed study of a variety of LHC signals in supersymmetric models where lepton number is promoted to an (approximate) U(1)_R symmetry. Such a symmetry has interesting implications for naturalness, as well as flavor- and CP-violation, among others. Interestingly, it makes large sneutrino vacuum expectation values phenomenologically viable, so that a slepton doublet can play the role of the down-type Higgs. As a result, (some of) the leptons and neutrinos are incorporated into the chargino and neutralino sectors. This leads to characteristic decay patterns that can be experimentally tested at the LHC. The corresponding collider phenomenology is largely determined by the new approximately conserved quantum number, which is itself closely tied to the presence of "leptonic R-parity violation". We find rather loose bounds on the first and second generation squarks, arising from a combination of suppressed production rates together with relatively small signal efficiencies of the current searches. Naturalness would indicate that such a framework should be discovered in the near future, perhaps through spectacular signals exhibiting the lepto-quark nature of the third generation squarks. The presence of fully visible decays, in addition to decay chains involving large missing energy (in the form of neutrinos) could give handles to access the details of the spectrum of new particles, if excesses over SM background were to be observed. The scale of neutrino masses is intimately tied to the source of U(1)_R breaking, thus opening a window into the R-breaking sector through neutrino physics. Further theoretical aspects of the model have been presented in a recent companion paper.
TL;DR: In this paper, the authors discuss methods of parsing direct and indirect information from collider experiments regarding the Higgs boson and describe simple ways in which experimental likelihoods can be consistently reconstructed and interfaced with model predictions in pertinent parameter spaces.
Abstract: In this review, we discuss methods of parsing direct and indirect information from collider experiments regarding the Higgs boson and describe simple ways in which experimental likelihoods can be consistently reconstructed and interfaced with model predictions in pertinent parameter spaces. Ultimately these methods are used to constrain a five-dimensional parameter space describing a model-independent framework for electroweak symmetry breaking. We review prevalent scenarios for extending the electroweak symmetry breaking sector relative to the Standard Model and emphasize their predictions for nonstandard Higgs phenomenology that could be observed in LHC data if naturalness is realized in particular ways. Specifically we identify how measurements of Higgs couplings can be used to imply the existence of new physics at particular scales within various contexts, highlighting some parameter spaces of interest in order to give examples of how the data surrounding the new state can most effectively be used to constrain specific models of weak scale physics.
TL;DR: In this paper, the authors propose an approach for a dynamic framework that permits an integrative use of naturalness in debate, by connecting three sorts of meaning that return regularly in the arguments brought forward in debate; cultural, technological, and ecological.
Abstract: This paper argues that in modern (agro)biotechnology, (un)naturalness as an argument contributed to a stalemate in public debate about innovative technologies. Naturalness in this is often placed opposite to human disruption. It also often serves as a label that shapes moral acceptance or rejection of agricultural innovative technologies. The cause of this lies in the use of nature as a closed, static reference to naturalness, while in fact “nature” is an open and dynamic concept with many different meanings. We propose an approach for a dynamic framework that permits an integrative use of naturalness in debate, by connecting three sorts of meaning that return regularly in the arguments brought forward in debate; cultural, technological, and ecological. We present these as aspects of nature that are always present in the argument of naturalness. The approach proposes a dynamic relation between these aspects, formed by gradients of naturalness, which in turn are related to ethical concerns. In this way we come to an overview that makes it possible to give individual arguments a relative place and that does justice to the temporality of the concept of nature and the underlying ethical concerns stakeholders have in respect to innovation in agriculture.
TL;DR: In this paper, the authors study the phenomenology of a simple model realizing the Little Higgs mechanism and present the current bounds on the model from precision electroweak fits, flavor physics, and direct searches at the LHC.
Abstract: Naturalness demands that the quadratic divergence of the one-loop top contribution to the Higgs mass be cancelled at a scale below 1 TeV. This can be achieved by introducing a fermionic (spin-1/2) top partner, as in, for example, Little Higgs models. In this paper, we study the phenomenology of a simple model realizing this mechanism. We present the current bounds on the model from precision electroweak fits, flavor physics, and direct searches at the LHC. The lower bound on the top partner mass from precision electroweak data is approximately 500 GeV, while the LHC bound with 5/fb of data at sqrt(s)=7 TeV is about 450 GeV. Given these bounds, the model can incorporate a 125 GeV Higgs with minimal fine-tuning of about 20%. We conclude that natural electroweak symmetry breaking with a fermionic top partner remains a viable possibility. We also compute the Higgs decay rates into gauge bosons, and find that significant, potentially observable deviations from the Standard Model predictions may occur.
TL;DR: In this article, the argument from naturalness has been extended to compare different models of the physics beyond the Standard Model and that naturalness in this case can at best be understood a socio-historic heuristic.
Abstract: Fine-tuning arguments are a frequent find in the literature on quantum field theory. They are based on naturalness—an aesthetic criterion that was given a precise definition in the debates on the Higgs mechanism. We follow the history of such definitions and of their application at the scale of electroweak symmetry breaking. They give rise to a special interpretation of probability, which we call Gedankenfrequency. Finally, we show that the argument from naturalness has been extended to comparing different models of the physics beyond the Standard Model and that naturalness in this case can at best be understood a socio-historic heuristic.
TL;DR: In this paper, the naturalness of the Minimal Supersymmetric Standard Model (MSSM) in the light of recent LHC results from the ATLAS and CMS experiments is analyzed.
Abstract: We analyse the naturalness of the Minimal Supersymmetric Standard Model (MSSM) in the light of recent LHC results from the ATLAS and CMS experiments. We study non-universal boundary conditions for the scalar and the gaugino sector, with fixed relations between some of the soft breaking parameters, and find a significant reduction of fine-tuning for non-universal gaugino masses. For a Higgs mass of about 125 GeV, as observed recently, we find parameter regions with a fine-tuning of O(10), taking into account experimental and theoretical uncertainties. These regions also survive after comparison with simplified model searches in ATLAS and CMS. For a fine-tuning less than 20 the lightest neutralino is expected to be lighter than about 400 GeV and the lighter stop can be as heavy as 3.5 TeV. On the other hand, the gluino mass is required to be above 1.5 TeV. For non-universal gaugino masses, we discuss which fixed GUT scale ratios can lead to a reduced fine-tuning and find that the recent Higgs results have a strong impact on which ratio is favoured. We also discuss the naturalness of GUT scale Yukawa relations, comparing the non-universal MSSM with the CMSSM.
TL;DR: In this article, the authors examine natural scenarios where supersymmetry is present, but was hidden from 2011 searches due to violation of R-parity and the absence of a large missing transverse momentum signature.
Abstract: Gluinos that result in classic large missing transverse momentum signatures at the LHC have been excluded by 2011 searches if they are lighter than around 800 GeV. This adds to the tension between experiment and supersymmetric solutions of the naturalness problem, since the gluino is required to be light if the electroweak scale is to be natural. Here, we examine natural scenarios where supersymmetry is present, but was hidden from 2011 searches due to violation of R-parity and the absence of a large missing transverse momentum signature. Naturalness suggests that third generation states should dominate gluino decays and we argue that this leads to a generic signature in the form of same-sign, flavour-ambivalent leptons, without large missing transverse momentum. As a result, searches in this channel are able to cover a broad range of scenarios with some generality and one should seek gluinos that decay in this way with masses below a TeV. We encourage the LHC experiments to tailor a search for supersymmetry in this form. We consider a specific case that is good at hiding: baryon number violation, and estimate that the most constraining existing search from 2011 data implies a lower bound on the gluino mass of 550 GeV.
TL;DR: In the last thirty years, there have been a number of attempts to analyse the distinction between intrinsic and extrinsic properties in terms of the facts about naturalness, each of which involves David Lewis as mentioned in this paper.
Abstract: Over the last thirty years there have been a number of attempts to analyse the distinction between intrinsic and extrinsic properties in terms of the facts about naturalness. This article discusses the three most influential of these attempts, each of which involve David Lewis. These are Lewis's 1983 analysis, his 1986 analysis, and his joint 1998 analysis with Rae Langton.
TL;DR: In this paper, the authors proposed an approach based on comparison of the real tree species composition with natural potential vegetation, e.g. forest stands naturalness degree, is to be used in the ecosystem platform way.
Abstract: Forest stands naturalness degree represents the real tree species composition comparison with the tree species on natural vegetation level - It means forest typology units. The natural tree species composition is derived from Typological System of UHUL (Forest Management Institute). The degree of naturalness of forests is one of the attributes for the assessment of the ecological stability of forests, whilst the broader basis for analysis of sustainable development of the territory.The real tree species composition comes from the forest management planes database and the natural potential vegetation one from typological sites units (forest site complex). Forests types complex is a higher unit of this system hierarchy.The solution based on comparison of the real species composition with natural potential vegetation, e.g. forest stands naturalness degree, is to be used in the ecosystem platform way. The preparation of entry data, e.g. allocation of structured stand type code to the real and natural species composition precedes the analysis itself. Then follows the tree species index calculation which means the final sum of tree index present and any absent species. This index presents the difference between the real tree condition and the model one. It is used entirely original concept algorithm of structured stand types.This algorithm allows for the application computer technology and process so the range from forest stand group of up to the large territory (CZ).The naturalness degree classification is defined on 0-6 levels, from zero degree for introduced species, 3rd degree for cultural forests, to 6th degree for those with natural tree composition. The limited criterion is the stand naturalness degree which should be on 4th level and above.This method is for 15 years of application not only in the works of forestry sites typology completely worked.
TL;DR: In this article, the authors assessed the spatio-temporal variation of land use in the catchment basins of Fiastra and Salino (central Italy) and its effect on landscape naturalness over a 30-year period (1978-2008).
Abstract: This work assessed the spatio-temporal variation of land use in the catchment basins of Fiastra and Salino (central Italy) and its effect on landscape naturalness over a 30-year period (1978–2008). The study area (centroid coordinates 43°7′29.44′′ N; 13°20′34.56′′E) was divided into ecologically homogeneous units (land units) in terms of substrate, bioclimatic belt, and aspect using a GIS-based hierarchical approach for landscape classification and mapping. Land units were characterized from a phytosociological viewpoint, and their naturalness evaluated using the Index of Landscape Conservation status. Comparison of current and past vegetation naturalness of land units was used to prepare the map of changes in landscape naturalness in the Fiastra and Salino catchment basins (central Italy) at a scale of 1:50,000. It was found that, while the change of naturalness in the whole study area was around zero, the pattern of distribution of this change was heterogeneous: naturalness increased in land units of hi...
TL;DR: In this paper, the authors argue that natural properties are real and their naturalness no more comes by degrees than does the naturalness of the things that have them, and they attack two contrary views: one denies that nature has joints, taking the properties we call natural to be merely artefacts of our theories.
Abstract: This paper attacks two contrary views. One denies that nature has joints, taking the properties we call natural to be merely artefacts of our theories. The other accepts real natural properties but takes their naturalness to come by degrees. I argue that both are wrong: natural properties are real, and their naturalness no more comes by degrees than does the naturalness of the things that have them.1
09 Sep 2012
TL;DR: The current study obtained the same result as the previous study: that timing is more important than pitch in improving the naturalness of L2 speech.
Abstract: This study aims to identify the crucial prosodic factor for native speakers' naturalness judgement of L2 pronunciation. Prosodic features are known to have more impact on the naturalness of L2 learners' pronunciation than segmental features do. Among prosodic features, timing and pitch are looked at in this study as major prosodic factors which affect native speakers' naturalness judgement of L2 learners' pronunciation. To examine the relative importance of timing and pitch, we synthesized stimuli using STRAIGHT to produce well-controlled timing and pitch errors. Native Japanese listeners assessed the naturalness of these stimuli and the result was compared with the one obtained using natural speech stimuli. The current study obtained the same result as the previous study: that timing is more important than pitch in improving the naturalness of L2 speech.