Wrong Sign Research Articles

Constraints on the s−s¯ asymmetry of the proton in chiral effective theory

We compute the $s-\bar s$ asymmetry in the proton in chiral effective theory, using phenomenological constraints based upon existing data. Unlike previous meson cloud model calculations, which accounted for kaon loop contributions with on-shell intermediate states alone, this work includes off-shell terms and contact interactions, which impact the shape of the $s-\bar s$ difference. We identify a valence-like component of $s(x)$ which is balanced by a $\delta$-function contribution to $\bar s(x)$ at $x=0$, so that the integrals of $s$ and $\bar s$ over the experimentally accessible region $x > 0$ are not equal. Using a regularization procedure that preserves chiral symmetry and Lorentz invariance, we find that existing data limit the integrated value of the second moment of the asymmetry to the range $-0.07 \times 10^{-3} \leq \langle x(s-\bar s) \rangle \leq 1.12 \times 10^{-3}$ at a scale of $Q^2=1 $GeV$^2$. This is too small to account for the NuTeV anomaly and of the wrong sign to enhance it.

Weyl gauge-vector and complex dilaton scalar for conformal symmetry and its breaking

Instead of the scalar "dilaton" field that is usually adopted to construct conformally invariant Lagrangians for gravitation, we here propose a hybrid construction, involving both a complex dilaton scalar and a Weyl gauge-vector, in accord with Weyl's original concept of a non-Riemannian conformal geometry with a transport law for length and time intervals, for which this gauge vector is required. Such a hybrid construction permits us to avoid the wrong sign of the dilaton kinetic term (the ghost problem) that afflicts the usual construction. The introduction of a Weyl gauge-vector and its interaction with the dilaton also has the collateral benefit of providing an explicit mechanism for spontaneous breaking of the conformal symmetry, whereby the dilaton and the Weyl gauge-vector acquire masses somewhat smaller than m/sub/P by the Coleman-Weinberg mechanism. Conformal symmetry breaking is assumed to precede inflation, which occurs later by a separate GUT or electroweak symmetry breaking, as in inflationary models based on the Higgs boson.

Evaluation of the interdecadal variability of sea surface temperature and sea level in the Pacific in CMIP3 and CMIP5 models

With significant impacts on the regional weather and climate, interdecadal climate variability is of great importance in understanding historical observations and predicting the climate in the near future. Using the currently available observation-based products, this study evaluates the ability of climate models participating in phases 3 and 5 of the Coupled Model Intercomparison Project (CMIP3 and CMIP5) to simulate the dominant interdecadal variability in the Pacific, i.e. the Interdecadal Pacific Oscillation (IPO). Our results indicate that compared with the CMIP3 models, the CMIP5 models exhibit slightly better performance in reproducing the observed interdecadal variability patterns of both sea surface temperature (SST) and sea level, and also exhibit smaller inter-model spread. Climate models tend to simulate more realistic interdecadal variability patterns for SST than for sea level. A prominent deficiency among CMIP3 and CMIP5 models lies in the northwestern tropical Pacific, where the observations show large sea level variations associated with the IPO, but the simulations are usually much weaker or even of the wrong sign. These biases can be generally associated with the inaccurate representation of wind forcing patterns at the corresponding latitudes (∼12°N). We further suggest that the air–sea coupling may play a role in the bias of interdecadal wind patterns in coupled climate models, and the representation of climatological mean states in climate models could influence the simulated interdecadal variability patterns. This study provides necessary skill information on climate models for further studying the Pacific interdecadal variability, as well as for better distinguishing the climate change signal from internal climate variability.

Phantom space–times in fake supergravity

We discuss phantom metrics admitting Killing spinors in fake N=2, D=4 supergravity coupled to vector multiplets. The Abelian U(1) gauge fields in the fake theory have kinetic terms with the wrong sign. We solve the Killing spinor equations for the standard and fake theories in a unified fashion by introducing a parameter which distinguishes between the two theories. The solutions found are fully determined in terms of algebraic conditions, the so-called stabilisation equations, in which the symplectic sections are related to a set of functions. These functions are harmonic in the case of the standard supergravity theory and satisfy the wave-equation in flat (2+1)-space–time in the fake theory. Explicit examples are given for the minimal models with quadratic prepotentials.

Identification of asymmetric conditional heteroscedasticity in the presence of outliers

The identification of asymmetric conditional heteroscedasticity is often based on sample cross-correlations between past and squared observations. In this paper we analyse the effects of outliers on these cross-correlations and, consequently, on the identification of asymmetric volatilities. We show that, as expected, one isolated big outlier biases the sample cross-correlations towards zero and hence could hide true leverage effect. Unlike, the presence of two or more big consecutive outliers could lead to detecting spurious asymmetries or asymmetries of the wrong sign. We also address the problem of robust estimation of the cross-correlations by extending some popular robust estimators of pairwise correlations and autocorrelations. Their finite sample resistance against outliers is compared through Monte Carlo experiments. Situations with isolated and patchy outliers of different sizes are examined. It is shown that a modified Ramsay-weighted estimator of the cross-correlations outperforms other estimators in identifying asymmetric conditionally heteroscedastic models. Finally, the results are illustrated with an empirical application.

BEHAVIORAL HAZARD IN HEALTH INSURANCE.

A fundamental implication of standard moral hazard models is overuse of low-value medical care because copays are lower than costs. In these models, the demand curve alone can be used to make welfare statements, a fact relied on by much empirical work. There is ample evidence, though, that people misuse care for a different reason: mistakes, or "behavioral hazard." Much high-value care is underused even when patient costs are low, and some useless care is bought even when patients face the full cost. In the presence of behavioral hazard, welfare calculations using only the demand curve can be off by orders of magnitude or even be the wrong sign. We derive optimal copay formulas that incorporate both moral and behavioral hazard, providing a theoretical foundation for value-based insurance design and a way to interpret behavioral "nudges." Once behavioral hazard is taken into account, health insurance can do more than just provide financial protection - it can also improve health care efficiency.

Subtleties in the BABAR measurement of time-reversal violation

A first measurement of time-reversal (T) asymmetries that are not also CP asymmetries has been recently achieved by the BABAR collaboration. In this talk, which follows the work done in Ref. [1], I discuss the subtleties of this measurement in the presence of direct CP violation, CPT violation, wrong strangeness decays and wrong sign semi-leptonic decays. In particular, I explain why, in order to identify the measured asymmetries with time-reversal violation, one needs to assume (i) the absence of wrong strangeness decays or of CPT violation in strangeness changing decays, and (ii) the absence of wrong sign decays.

Cascades in nonlocal turbulence.

We consider developed turbulence in the two-dimensional Gross-Pitaevskii model, which describes wide classes of phenomena from atomic and optical physics to condensed matter, fluids, and plasma. The well-known difficulty of the problem is that the hypothetical local spectra of both inverse and direct cascades in the weak-turbulence approximation carry fluxes that are either zero or have the wrong sign; Such spectra cannot be realized. We analytically derive the exact flux constancy laws (analogs of Kolmogorov's 4/5 law for incompressible fluid turbulence), expressed via the fourth-order moment and valid for any nonlinearity. We confirm the flux laws in direct numerical simulations. We show that a constant flux is realized by a nonlocal wave interaction in both the direct and inverse cascades. Wave spectra (second-order moments) are close to slightly (logarithmically) distorted thermal equilibrium in both cascades.

On the Relationships between Subtropical Clouds and Meteorology in Observations and CMIP3 and CMIP5 Models

AbstractClimate models’ simulation of clouds over the eastern subtropical oceans contributes to large uncertainties in projected cloud feedback to global warming. Here, interannual relationships of cloud radiative effect and cloud fraction to meteorological variables are examined in observations and in models participating in phases 3 and 5 of the Coupled Model Intercomparison Project (CMIP3 and CMIP5, respectively). In observations, cooler sea surface temperature, a stronger estimated temperature inversion, and colder horizontal surface temperature advection are each associated with larger low-level cloud fraction and increased reflected shortwave radiation. A moister free troposphere and weaker subsidence are each associated with larger mid- and high-level cloud fraction and offsetting components of shortwave and longwave cloud radiative effect. It is found that a larger percentage of CMIP5 than CMIP3 models simulate the wrong sign or magnitude of the relationship of shortwave cloud radiative effect to sea surface temperature and estimated inversion strength. Furthermore, most models fail to produce the sign of the relationship between shortwave cloud radiative effect and temperature advection. These deficiencies are mostly, but not exclusively, attributable to errors in the relationship between low-level cloud fraction and meteorology. Poor model performance also arises due to errors in the response of mid- and high-level cloud fraction to variations in meteorology. Models exhibiting relationships closest to observations tend to project less solar reflection by clouds in the late twenty-first century and have higher climate sensitivities than poorer-performing models. Nevertheless, the intermodel spread of climate sensitivity is large even among these realistic models.

Constraints on hard spectator scattering and annihilation corrections in Bu,d → PV decays within QCD factorization

In this paper, we investigate the contributions of hard spectator scattering and annihilation in B→PV decays within the QCD factorization framework. With available experimental data on B→πK⁎,ρK,πρ and Kϕ decays, comprehensive χ2 analyses of the parameters XA,Hi,f(ρA,Hi,f,ϕA,Hi,f) are performed, where XAf(XAi) and XH are used to parameterize the endpoint divergences of the (non)factorizable annihilation and hard spectator scattering amplitudes, respectively. Based on χ2 analyses, it is observed that (1) The topology-dependent parameterization scheme is feasible for B→PV decays; (2) At the current accuracy of experimental measurements and theoretical evaluations, XH=XAi is allowed by B→PV decays, but XH≠XAf at 68% C.L.; (3) With the simplification XH=XAi, parameters XAf and XAi should be treated individually. The above-described findings are very similar to those obtained from B→PP decays. Numerically, for B→PV decays, we obtain (ρA,Hi,ϕA,Hi[°])=(2.87−1.95+0.66,−145−21+14) and (ρAf,ϕAf[°])=(0.91−0.13+0.12,−37−9+10) at 68% C.L. With the best-fit values, most of the theoretical results are in good agreement with the experimental data within errors. However, significant corrections to the color-suppressed tree amplitude α2 related to a large ρH result in the wrong sign for ACPdir(B−→π0K⁎−) compared with the most recent BABAR data, which presents a new obstacle in solving “ππ” and “πK” puzzles through α2. A crosscheck with measurements at Belle (or Belle II) and LHCb, which offer higher precision, is urgently expected to confirm or refute such possible mismatch.

Precise discussion of time-reversal asymmetries in B-meson decays

BaBar collaboration announced that they observed time reversal (T) asymmetry through $B$ meson system. In the experiment, time dependencies of two distinctive processes, $B_- \rightarrow \bar{B^0}$ and $\bar{B^0}\rightarrow B_-$($-$ expresses CP value) are compared with each other. In our study, we examine event number difference of these two processes. In contrast to the BaBar asymmetry, the asymmetry of events number includes the overall normalization difference for rates. Time dependence of the asymmetry is more general and it includes terms absent in one used by BaBar collaboration. Both of the BaBar asymmetry and ours are naively thought to be T-odd since two processes compared are related with flipping time direction. We investigate the time reversal transformation property of our asymmetry. Using our notation, one can see that the asymmetry is not precisely a T-odd quantity, taking into account indirect CP and CPT violation of K meson systems. The effect of $\epsilon_K$ is extracted and gives rise to $\mathcal{O}(10^{-3})$ contribution. The introduced parameters are invariant under rephasing of quarks so that the coefficients of our asymmetry are expressed as phase convention independent quantities. Some combinations of the asymmetry enable us to extract parameters for wrong sign decays of $B_d$ meson, CPT violation, etc. We also study the reason why the T-even terms are allowed to contribute to the asymmetry, and find that several conditions are needed for the asymmetry to be a T-odd quantity.

The impact of ENSO on Southern African rainfall in CMIP5 ocean atmosphere coupled climate models

We study the ability of 24 ocean atmosphere global coupled models from the Coupled Model Intercomparison Project 5 (CMIP5) to reproduce the teleconnections between El Nino Southern Oscillation (ENSO) and Southern African rainfall in austral summer using historical forced simulations, with a focus on the atmospheric dynamic associated with El Nino. Overestimations of summer rainfall occur over Southern Africa in all CMIP5 models. Abnormal westward extensions of ENSO patterns are a common feature of all CMIP5 models, while the warming of the Indian Ocean that happens during El Nino is not correctly reproduced. This could impact the teleconnection between ENSO and Southern African rainfall which is represented with mixed success in CMIP5 models. Large-scale anomalies of suppressed deep-convection over the tropical maritime continent and enhanced convection from the central to eastern Pacific are correctly simulated. However, regional biases occur above Africa and the Indian Ocean, particularly in the position of the deep convection anomalies associated with El Nino, which can lead to the wrong sign in rainfall anomalies in the northwest part of South Africa. From the near-surface to mid-troposphere, CMIP5 models underestimate the observed anomalous pattern of pressure occurring over Southern Africa that leads to dry conditions during El Nino years.

Natural Experiment Policy Evaluation: A Critique

We argue exogenous random treatment is insu¢ cient for valid inference regarding the sign and magnitude of causal eects in dynamic environments. In such settings, treatment responses must be understood as contingent upon the typically unmodeled policy generating process. With binary assignment, this results in quantitatively signi…cant attenuation bias. With more than two policy states, treatment responses can be biased downward, upward, or have the wrong sign. Further, it is not only generally invalid to extrapolate elasticities across policy processes, as argued by Lucas (1976), but also to extrapolate within the same policy process. We derive auxiliary assumptions beyond exogeneity for valid inference in dynamic settings. If all possible policy transitions are rare events, treatment responses approximate causal eects. However, reliance on rare events is overly-restrictive as the necessary and su¢ cient conditions for equality of treatment responses and causal eects is that policy variable changes have mean zero. If these conditions are not met, we show how treatment responses can nevertheless be corrected and mapped back to causal eects or extrapolated to forecast responses to future policy changes. � We thank Akitada Kasahara and Boris Radnaev for valuable research assistance and advice. We also thank seminar participants at LBS, Simon Fraser University, UBC, Koc University, and the Stanford Conference on Causality in the Social Sciences.

Technology for Electrostatic Separation of Charged Toner Particles with Different Sign by Utilizing Electrostatic Traveling Wave

The author has studied toner transport utilizing electrostatic traveling wave with high-speed photography, measurements of toner charge distributions, and numerical simulations. In this study, the author has concentrated on the toner cloud above the main transport stream. The mechanism of the toner cloud formation has been identified, and a method to separate the correct sign toner from the wrong sign toner particles utilizing the mechanism has been developed. For the fewer toner particles and a lower speed toner transport, we used high-speed photography to observe an arch-shaped toner cloud above the transport. Using a simplified model, we have found that such an arch-shaped toner cloud is formed by the effect of air-drag. On the other hand, in the development system conditions such as a higher toner concentration and a faster speed toner transport, the arch-like cloud becomes dense because of the effect of the electrostatic attraction force. The author has proposed that the cloud comprises the same number of toner particles of both signs, and has designed toner separation and re-charging system using vertical toner transporting.

Wrong sign and symmetric limits and non-decoupling in 2HDMs

We analyse the possibility that, in two Higgs doublet models, one or more of the Higgs couplings to fermions or to gauge bosons change sign, relative to the respective Higgs Standard Model couplings. Possible sign changes in the coupling of a neutral scalar to charged ones are also discussed. These \textit{wrong signs} can have important physical consequences, manifesting themselves in Higgs production via gluon fusion or Higgs decay into two gluons or into two photons. We consider all possible wrong sign scenarios, and also the \textit{symmetric limit}, in all possible Yukawa implementations of the two Higgs doublet model, in two different possibilities: the observed Higgs boson is the lightest CP-even scalar, or the heaviest one. We also analyse thoroughly the impact of the currently available LHC data on such scenarios. With all 8 TeV data analysed, all wrong sign scenarios are allowed in all Yukawa types, even at the 1$\sigma$ level. However, we will show that B-physics constraints are crucial in excluding the possibility of wrong sign scenarios in the case where $\tan \beta$ is below 1. We will also discuss the future prospects for probing the wrong sign scenarios at the next LHC run. Finally we will present a scenario where the alignment limit could be excluded due to non-decoupling in the case where the heavy CP-even Higgs is the one discovered at the LHC.

H → Zγ in the complex two Higgs doublet model

The latest LHC data confirmed the existence of a Higgs-like particle and made interesting measurements on its decays into $\gamma \gamma$, $Z Z^\ast$, $W W^\ast$, $\tau^+ \tau^-$, and $b \bar{b}$. It is expected that a decay into $Z \gamma$ might be measured at the next LHC round, for which there already exists an upper bound. The Higgs-like particle could be a mixture of scalar with a relatively large component of pseudoscalar. We compute the decay of such a mixed state into $Z \gamma$, and we study its properties in the context of the complex two Higgs doublet model, analysing the effect of the current measurements on the four versions of this model. We show that a measurement of the $h \rightarrow Z \gamma$ rate at a level consistent with the SM can be used to place interesting constraints on the pseudoscalar component. We also comment on the issue of a wrong sign Yukawa coupling for the bottom in Type II models.

Vertical mixing due to double diffusion in the tropical western Pacific

AbstractThis study calculates the vertical diffusivity and the fluxes of heat, salt, and buoyancy due to turbulence and double diffusion based on a 14 day time series of observations of the dissipation rates of turbulent kinetic energy and thermal variance at 0°N, 156°E from 25 October to 18 November 2012. Salt fingering dominates shear‐driven turbulence below 100 m. The estimated flux and associated vertical diffusivity due to double diffusion are approximately 1 order of magnitude higher for temperature and density and 2 orders of magnitude higher for salinity compared to values calculated from a turbulence model. Under weak turbulence conditions, the turbulence model significantly underestimates the magnitude of the vertical buoyancy flux with the flux having the wrong sign. Under these conditions, fluxes induced by double‐diffusive mixing need to be considered.

Event-plane correlations and hydrodynamic simulations of heavy ion collisions

We use a nonlinear response formalism to describe the event plane correlations measured by the ATLAS collaboration. With one exception ($\left\langle \cos(2\Psi_2 - 6\Psi_3 + 4 \Psi_4) \right\rangle$), the event plane correlations are qualitatively reproduced by considering the linear and quadratic response to the lowest cumulants. For the lowest harmonics such as $\left\langle \cos(2\Psi_2+3\Psi_3 - 5\Psi_5) \right\rangle$, the correlations are quantitatively reproduced, even when the naive Glauber model prediction has the wrong sign relative to experiment. The quantitative agreement for the higher plane correlations (especially those involving $\Psi_6$) is not as good. The centrality dependence of the correlations is naturally explained as an average of the linear and quadratic response.

Tree phenology responses to winter chilling, spring warming, at north and south range limits

Summary Increases in primary production may occur if plants respond to climate warming with prolonged growing seasons, but not if local adaptation, cued by photoperiod, limits phenological advance. It has been hypothesized that trees with diffuse‐porous xylem anatomy and early successional species may respond most to warming. Within species, northern populations may respond most due to the fact that growing seasons are relatively short. Species most sensitive to spring temperature may show little overall response to warming if reduced chilling in fall/winter offsets accelerated winter/spring development. Because current thermal models consider only highly aggregated variables, for example degree‐days or chilling units (temperature sums for a season or year), they may not accurately represent warming effects. We show that assumptions contained in current thermal (degree‐day) models are unrealistic for climate change analysis. Critical threshold parameters are not identifiable, and they do not actually have much to do with thresholds for development. Traditional models further overlook the discrete nature of observations, observation error and the continuous response of phenological development to temperature variation. An alternative continuous development model (CDM) that addresses these problems is applied to a large experimental warming study near northern and southern boundaries of 15 species in the eastern deciduous forest of the USA, in North Carolina and Massachusetts. Results provide a detailed time course of phenological development, including vernalization during winter and warming in spring, and challenge the basic assumptions of thermal models. Where traditional models find little evidence of a chilling effect (most are insignificant or have the wrong sign), the continuous development model finds evidence of chilling effects in most species. Contrary to the hypothesis that northern populations respond most, we find southern populations are most responsive. Because northern populations already have a compressed period for spring development, they may lack flexibility to further advance development. A stronger response in the southern range could allow residents to resist northward migration of immigrants as climate warms. If potential invaders fail to exploit a prolonged growing season to the same degree as residents, then there is a resident advantage. Hypothesized effects of warming for xylem anatomy and successional status are not supported by the 15 species in this study.

The India-ASEAN Free Trade Agreement: How Will Indian Industries Be Affected?

In this paper we apply the gravity model to international trade transactions between India and the ASEAN countries. The model is applied to all HS 6-digit codes for which trade between India and ASEAN takes place. The estimated equation is then used to simulate the trade impact under the alternative scenario of a Free Trade Agreement (FTA) between the two countries. The results of these simulations are then presented to find out the possible impact of the India ASEAN FTA on individual industries. Initially the analysis was done at the 2 digit HS level. However we found that the same set of industries at the two digit level will be both favourably and adversely affected due to the FTA. This necessitated disaggregation at the 6 digit, where individual industries in ASEAN that will be able to increase their export to India and the ones for which export by India will increase could be separated. The main conclusion is that intermediate goods will be more affected (both adversely and favourably for India) than final goods. Other conclusions include the fact that about fifty percent of the 6 digit products have insignificant tariff elasticity or the elasticity coefficient (even simple correlation between the rate of tariff and import) is of the wrong sign. The implication is obvious: tariffs do not matter at all for a major part of the industries and for them the agreement has no significance. In fact some of the most debated commodities fall in this category. For many of them though tariff rates have steadily increased overtime so has imports imparting a wrong sign to the tariff elasticity which means that reasons other than tariffs determine their imports and there is no point in putting them in the sensitive or exclusion list.