Negative / Null Result ReportOpen accessComputer Science
Waleed Abdallah, Raj Gandhi, Samiran Roy · 2020 · arXiv
We show that one of the simplest extensions of the Standard Model, the addition of a second Higgs doublet, when combined with a dark sector singlet scalar, allows us to: $i)$ explain the long-standing anomalies in the Liquid Scintillator Neutrino Detector (LSND) and MiniBooNE (MB) while maintaining compatibility with the null result from KARMEN, $ii)$ obtain, in the process, a portal to the dark sector, and $iii)$ comfortably account for the observed value of the muon $g-2$. Three singlet neutrinos allow for an understanding of observed neutrino mass-squared differences via a Type I seesaw, wi
Negative / Null Result ReportOpen accessPhysics
Ray Zhang, Dragan Huterer · 2009 · arXiv
We reassess the evidence that WMAP temperature maps contain a statistically significant "cold spot" by repeating the analysis using simple circular top-hat (disk) weights, as well as Gaussian weights of varying width. Contrary to previous results that used Spherical Mexican Hat Wavelets, we find no significant signal at any scale when we compare the coldest spot from our sky to ones from simulated Gaussian random, isotropic maps. We trace this apparent discrepancy to the fact that WMAP cold spot's temperature profile just happens to favor the particular profile given by the wavelet. Since rand
Negative / Null Result ReportOpen accessComputer Science
Feng Luo, Keith A. Olive, Jean-Philippe Uzan · 2011 · arXiv
We consider the effect of the coupled variations of fundamental constants on the nucleon magnetic moment. The nucleon g-factor enters into the interpretation of the measurements of variations in the fine-structure constant, alpha, in both the laboratory (through atomic clock measurements) and in astrophysical systems (e.g. through measurements of the 21 cm transitions). A null result can be translated into a limit on the variation of a set of fundamental constants, that is usually reduced to alpha. However, in specific models, particularly unification models, changes in alpha are always accomp
Negative / Null Result ReportOpen accessPhysics
Qiu-Ju Huang, Bao Wang, Jun-Jie Wei et al. · 2025 · arXiv
Axions or axion-like particles (ALPs) are well-motivated dark matter (DM) candidates whose coupling to photons induces periodic oscillations in the polarization angle of astrophysical light. This work reports the first search for such a signature using ten years of optical polarimetric monitoring of the blazar 1ES 1959+650. No statistically significant periodicity is detected using a Lomb-Scargle periodogram and Monte Carlo analysis. Assuming a central DM density in the host galaxy, this null result places tight upper limits on the ALP-photon coupling constant at $g_{aγ}<(5.8 \times 10^{-14}-1
Negative / Null Result Report
· 2019 · The Brown University Psychopharmacology Update
Augmenting sertraline with eicosapentaenoic acid (EPA) for 10 weeks did not improve depressive symptoms relative to placebo in a group of 144 patients with major depressive disorder and existing or high risk of heart disease, a randomized…
View details →DOI: 10.1002/pu.30472 Negative / Null Result Report
· 2019 · The Brown University Psychopharmacology Update
Six weeks of D‐cycloserine treatment for patients with depression who had responded to doses of ketamine did not improve depressive symptoms compared with placebo, a study has found. D‐cycloserine was found to maintain the anti‐suicidal…
View details →DOI: 10.1002/pu.30506 Negative / Null Result ReportOpen accessComputer Science
Shaaban Khalil, Qaisar Shafi · 1999 · arXiv
For varying values of $\tanβ$, we study the effect of CP violating phases from the soft supersymmetry breaking terms in string-inspired models on the relic abundance and detection rates of the lightest neutralino (LSP). We find that the phases have no significant effect on the LSP relic abundance but can have a substantial impact on the detection rates.
Negative / Null Result ReportOpen accessPhysics
David T. F Weldrake, Penny D Sackett, Kenneth C Freeman et al. · 2004 · arXiv
We present the results of a comprehensive wide field search for transiting ``Hot Jupiter'' planets (1d<P<16d) in the globular cluster 47 Tucanae. Motivated by the core null result of Gilliland and coworkers, this work further addresses the question of giant planet frequency in 47 Tuc by observing, from the ground, a 52'x52' field centered on the cluster for 30.4 nights. Hence this work is most sensitive to the uncrowded outer regions of the cluster and concentrates on 21,920 main sequence stars (~solar in mass). This work comprises the largest ground-based transit search of a globular cluster
Negative / Null Result ReportOpen accessComputer Science
C. Abel, N. J. Ayres, G. Ban et al. · 2022 · arXiv
Ultra-low-mass axions are a viable dark matter candidate and may form a coherently oscillating classical field. Nuclear spins in experiments on Earth might couple to this oscillating axion dark-matter field, when propagating on Earth's trajectory through our Galaxy. This spin coupling resembles an oscillating pseudo-magnetic field which modulates the spin precession of nuclear spins. Here we report on the null result of a demonstration experiment searching for a frequency modulation of the free spin-precession signal of \magHg in a \SI{1}{\micro\tesla} magnetic field. Our search covers the axi
Negative / Null Result ReportOpen accessComputer Science
Bin Zhu, Xuewen Liu · 2021 · arXiv
Flavor-specific scalar bosons exist in various Standard Model extensions and couple to a single generation of fermions via a global flavor symmetry breaking mechanism. Given this strategy, we propose a MeV flavor-specific scalar model in dimension-$5$ operator series, which explains the muon g-2 anomaly and proton radius puzzle by coupling with the muon and down-quark at the same time. The framework is consistent with the null result of high-intensity searches. Specifically, the supernova constraints for muon couplings become weakened by including the contribution of down-quark interaction. Th
Negative / Null Result ReportOpen accessPhysics
Kaustubh Rajwade, Duncan Lorimer, Loren Anderson · 2016 · arXiv
Although high-sensitivity surveys have revealed a number of highly dispersed pulsars in the inner Galaxy, none have so far been found in the Galactic centre (GC) region, which we define to be within a projected distance of 1~pc from Sgr~A*. This null result is surprising given that several independent lines of evidence predict a sizable population of neutron stars in the region. Here, we present a detailed analysis of both the canonical and millisecond pulsar populations in the GC and consider free-free absorption and multi-path scattering to be the two main sources of flux density mitigation.
Negative / Null Result ReportOpen accessComputer Science
A. V. Friesen, Yu. L. Kalinovsky, V. D. Toneev · 2019 · arXiv
A sharp peak in the $K^+/π^+$ ratio in relativistic heavy-ion collision is discussed in the framework of the SU(3) Polyakov-loop extended NJL model with vector interaction. In the model, the $K^+/π^+$ ratio was calculated along the chiral phase transition line for different values of the vector coupling $g_V$. We showed that the value of the vector coupling had no significant effect on the $K^+/π^+$ behaviour.
Negative / Null Result ReportOpen accessPhysics
Shunke Ai, He Gao · 2022 · arXiv
GRB 221009A is a bright Gamma-ray burst (GRB) with isotropic energy being larger than $10^{54} ~{\rm ergs}$. Its fairly low redshift makes it a promising candidate for high energy neutrino detection. However, a neutrino search for this GRB reported by the IceCube collaboration yielded a null result. In this paper, we utilize the upper limit from IceCube observation to test different GRB prompt emission models. We find that, at least for this specific burst, the dissipative photosphere model could be ruled out in a large parameter space. The internal shock model can survive only with a large bu
Negative / Null Result ReportOpen accessComputer Science
Ole Host, Ofer Lahav, Filipe B. Abdalla et al. · 2007 · arXiv
We present a showcase for deriving bounds on the neutrino masses from laboratory experiments and cosmological observations. We compare the frequentist and Bayesian bounds on the effective electron neutrino mass m_beta which the KATRIN neutrino mass experiment is expected to obtain, using both an analytical likelihood function and Monte Carlo simulations of KATRIN. Assuming a uniform prior in m_beta, we find that a null result yields an upper bound of about 0.17 eV at 90% confidence in the Bayesian analysis, to be compared with the frequentist KATRIN reference value of 0.20 eV. This is a signif
Negative / Null Result ReportOpen accessComputer Science
P. Danielewicz, G. Odyniec · 2021 · arXiv
Novel transverse-momentum technique is used to analyse charged-particle exclusive data for collective motion in the Ar+KCl reaction at 1.8 GeV/nucl. Previous analysis of this reaction, employing the standard sphericity tensor, revealed no significant effect. In the present analysis, collective effects are observed, and they are substantially stronger than in the Cugnon cascade model, but weaker than in the hydrodynamical model.
Negative / Null Result Report
Y Zhao, T Zhang, X Guo et al. · 2021 · Human Reproduction
Abstract Study question To compare the changing peripheral levels of inflammation-related cytokine profile during a 9-day period after blastocyst transfer between women who did and did not conceive. Summary answer:Successful implantation…
View details →DOI: 10.1093/humrep/deab130.416 Negative / Null Result ReportOpen accessEconomics, Econometrics and Finance
S. Meghna, N. Suresh, J. C. Usha · 2022 · arXiv
This study examines the impact of dividend policy on the performance of initial public offerings in India. The period of study is from the year 2011-2014. Monthly returns of the IPOs issued in the considered period and the Indian Stock Market Index (Nifty 50) were considered for the long-run performance study. The methodological tools used are long-run performance statistics and the GARCH model. The Dummy variable was used to measure the effect of dividends on the IPOs. The study reveals that the dividend policy has no significant effect on the stock prices of IPO.
Negative / Null Result ReportOpen accessPhysics
Patryk Mach · 2004 · arXiv
An analysis of the propagation of non stationary waves in the adiabatic region of stellar interior is presented. An equation of motion with an effective potential is derived, similar to the Zerilli equation known in the propagation of gravitational waves. The Huyghens principle is violated in this case and the energy diffusion outward null cones is expected. Numerical calculations demonstrate that the diffusion is weak for the case of standard Solar model; thus no significant effect corresponding to quasinormal modes can be expected. The likely reason for the absence of stronger features is th
Negative / Null Result ReportOpen accessPhysics
G. Rosenberg, H. -M. Guo, M. Franz · 2010 · arXiv
An infinitely thin solenoid carrying magnetic flux Phi (a `Dirac string') inserted into an ordinary band insulator has no significant effect on the spectrum of electrons. In a strong topological insulator, remarkably, such a solenoid carries protected gapless one-dimensional fermionic modes when Phi=hc/2e. These modes are spin-filtered and represent a distinct bulk manifestation of the topologically non-trivial insulator. We establish this `wormhole' effect by both general qualitative considerations and by numerical calculations within a minimal lattice model. We also discuss the possibility o
Negative / Null Result ReportOpen accessComputer Science
M. U. Ashraf, Junaid Tariq, A. M. Khan · 2022 · arXiv
We report the transverse momentum $p_T$ spectra of identified hadrons ($π^\pm$, $K^\pm$ and $p(\bar p)$) in Au+Au collisions at $\sqrt{s_{NN}}$ = 7.7 - 39 GeV from A Multi Phase Transport Model with string melting effect (AMPT-SM). During this study, a new set of parameters are explored to study the effect of hadronic cascade by varying hadronic cascade time $t_{max}$ = 30 $f$m/$c$ and 0.4 $f$m/$c$. No significant effect of this change is observed in the $p_T$ spectra of light hadrons and the AMPT-SM model reasonably reproduces the experimental data. To investigate the kinetic freeze-out prope
Negative / Null Result ReportOpen accessEconomics, Econometrics and Finance
Ruiwu Liu · 2021 · arXiv
Acemoglu and Johnson (2007) put forward the unprecedented view that health improvement has no significant effect on income growth. To arrive at this conclusion, they constructed predicted mortality as an instrumental variable based on the WHO international disease interventions to analyse this problem. I replicate the process of their research and eliminate some biases in their estimate. In addition, and more importantly, we argue that the construction of their instrumental variable contains a violation of the exclusion restriction of their instrumental variable. This negative correlation betw
Negative / Null Result ReportOpen accessComputer Science
Chathura Rajapakse, Wathsala Ariyarathna, Shanmugalingam Selvakan · 2024 · arXiv
This study investigates Sri Lankan ICT teachers' readiness to teach AI in schools, focusing on self-efficacy. A survey of over 1,300 teachers assessed their self-efficacy using a scale developed based on Bandura's theory. PLS-SEM analysis revealed that teachers' self-efficacy was low, primarily influenced by emotional and physiological states and imaginary experiences related to AI instruction. Mastery experiences had a lesser impact, and vicarious experiences and verbal persuasion showed no significant effect. The study highlights the need for a systemic approach to teacher professional devel
Negative / Null Result ReportOpen accessComputer Science
Muon g-2 Collaboration, :, G. W. Bennett · 2007 · arXiv
The spin precession frequency of muons stored in the $(g-2)$ storage ring has been analyzed for evidence of Lorentz and CPT violation. Two Lorentz and CPT violation signatures were searched for: a nonzero $Δω_{a}$ (=$ω_{a}^{μ^{+}}-ω_{a}^{μ^{-}}$); and a sidereal variation of $ω_{a}^{μ^{\pm}}$. No significant effect is found, and the following limits on the standard-model extension parameters are obtained: $b_{Z} =-(1.0 \pm 1.1)\times 10^{-23}$ GeV; $(m_μd_{Z0}+H_{XY}) = (1.8 \pm 6.0 \times 10^{-23})$ GeV; and the 95% confidence level limits $\check{b}_{\perp}^{μ^{+}}< 1.4 \times 10^{-24}$ GeV
Negative / Null Result Report
Cui L, Harrison L, Liu J · 2022 · Preprint
Many studies have failed to replicate the disfluency effect (i.e. disfluent font better than fluent font) on Cognitive Reflection Test (CRT) performance shown in Alter et al. (2007). Those studies manipulated perceptual disfluency using…
View details →DOI: 10.31234/osf.io/qdxw3 Negative / Null Result ReportOpen accessComputer Science
Imam tahyudin · 2013 · arXiv
The purpose of this research was to determine the influence of Internet Retail Service Quality (IRSQ) (website performance, access, security, sensation, and information) to the satisfaction www.kebanaran.com online shoppers. The method of analysis used was path analysis. Based on the research results influence IRSQ variables (performance, access, sensation, and information security), performance variables (X1), access (X2) and sensation (X3) had no significant effect on satisfaction (Y). It showsthat the online shopping website www.kebanaran.com already apply standard terms online stores in ge
Negative / Null Result ReportOpen accessPhysics
L. R. Abramo, R. P. Woodard · 1998 · arXiv
We consider quantum mechanical corrections to a homogeneous, isotropic and spatially flat geometry whose scale factor expands classically as a general power of the co-moving time. The effects of both gravitons and the scalar inflaton are computed at one loop using the manifestly causal formalism of Schwinger with the Feynman rules recently developed by Iliopoulos {\it et al.} We find no significant effect, in marked contrast with the result obtained by Mukhanov {\it et al.} for chaotic inflation based on a quadratic potential. By applying the canonical technique of Mukhanov {\it et al.} to the
Negative / Null Result ReportOpen accessPhysics
Ulrich Kolb, Isabelle Baraffe · 1999 · arXiv
Using improved, up-to-date stellar input physics tested against observations of low-mass stars and brown dwarfs we calculate the secular evolution of low-mass donor cataclysmic variables (CVs), including those which form with a brown dwarf donor. Our models confirm the mismatch between the calculated minimum period (Pmin ~ 70 min) and the observed short-period cut-off (~ 80 min) in the CV period histogram. We find that tidal and rotational corrections applied to the one-dimensional stellar structure equations have no significant effect on the period minimum. Theoretical period distributions sy
Negative / Null Result ReportOpen accessPhysics
X. S. Wu, P. W. Adams, Y. Yang et al. · 2005 · arXiv
We present a detailed study of the effects of interface spin-orbit coupling (ISOC) on the critical field behavior of non-centrosymmetric (NCS), ultra-thin superconducting Be/Au bilayers. Parallel field measurements were made in bilayers with Be thicknesses in the range of 2 - 10 nm and Au coverages of 0.5 nm. Though the Au had no significant effect on the superconducting gap, it produced profound changes in the spin states of the system. In particular, the parallel critical field exceeded the Clogston limit by an order of magnitude in the thinnest films studied. In addition, the parallel criti
Negative / Null Result ReportOpen accessComputer Science
Bruce W. Lee, JaeHyuk Lim · 2024 · arXiv
We argue that language-only models don't learn the physical manifestation of language. We present an empirical investigation of visual-auditory properties of language through a series of tasks, termed H-Test. These tasks highlight a fundamental gap between human linguistic understanding and the sensory-deprived linguistic understanding of LLMs. In support of our hypothesis, 1. deliberate reasoning (Chain-of-Thought), 2. few-shot examples, or 3. stronger LLM from the same model family (LLaMA 2 13B -> LLaMA 2 70B) has no significant effect on H-Test performance. We bring in the philosophical cas
Negative / Null Result ReportOpen accessPhysics
Stephen C. Thompson, Richard J. Meyer, Douglas C. Markley · 2013 · arXiv
Underwater acoustic transducers often include a stack of thickness polarized piezoelectric material pieces of alternating polarity interspersed with electrodes, bonded together and electrically connected in parallel. The stack is normally much shorter than a quarter wavelength at the fundamental resonance frequency, so that the mechanical behavior of the transducer is not affected by the segmentation. When the transducer bandwidth is less than a half octave, as has conventionally been the case, stack segmentation has no significant effect on the mechanical behavior of the device. However, when
