Negative / Null Result ReportOpen accessPhysics
Diego F. Torres, Stephen Reucroft, Olaf Reimer et al. · 2003 · arXiv
With the aim of testing recent claims for a particularly strong correlation between ultra-high energy cosmic rays (UHECRs), observed with the AGASA and the Yakutsk experiments, and a sample of BL Lacertae (BL Lacs), we here conduct a blind statistical assessment. We search for associations between the same set of BL Lac objects and the arrival directions of 33 relevant UHECRs observed with the Haverah Park and the Volcano Ranch experiments. Within the accuracy of angle determination, there are no positional coincidences. The probability that this null result arises as a statistical fluctuation
View details →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
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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
View details →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.
View details →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.
View details →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
View details →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
View details →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.
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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 →Negative / Null Result ReportOpen accessComputer Science
D. V. Ahluwalia, S. P. Horvath · 2010 · arXiv
In the very special relativity (VSR) proposal by Cohen and Glashow, it was pointed out that invariance under HOM(2) is both necessary and sufficient to explain the null result of the Michelson-Morely experiment. It is the quantum field theoretic demand of locality, or the requirement of P, T, CP, or CT invariance, that makes invariance under the Lorentz group a necessity. Originally it was conjectured that VSR operates at the Planck scale; we propose that the natural arena for VSR is at energies similar to the standard model, but in the dark sector. To this end we provide an ab initio spinor r
View details →Negative / Null Result ReportOpen accessComputer Science
Alejandro Ibarra, Andreas Rappelt · 2017 · arXiv
We present a method to calculate, without making assumptions about the local dark matter velocity distribution, the maximal and minimal number of signal events in a direct detection experiment given a set of constraints from other direct detection experiments and/or neutrino telescopes. The method also allows to determine the velocity distribution that optimizes the signal rates. We illustrate our method with three concrete applications: i) to derive a halo-independent upper limit on the cross section from a set of null results, ii) to confront in a halo-independent way a detection claim to a
View details →Negative / Null Result ReportOpen accessPhysics
D. Sarenac, O. Lailey, D. V. Garrad et al. · 2026 · arXiv
A recent proposal suggested that neutron orbital angular momentum (OAM) states could be detected via spin-polarized absorption in polarized 3He, with predicted cross-section variations linked to the neutron's OAM. We experimentally tested this hypothesis using spin-polarized neutron beams with OAM =-2 to 2, generated by fork-dislocation phase-gratings, and transmitted through a polarized 3He cell. Within statistical precision, no OAM-dependent change in the absorption cross section was observed. This null result places stringent constraints on polarized 3He-based OAM detection schemes. The abs
View details →Negative / Null Result ReportOpen accessComputer Science
Shaaban Khalil · 1999 · arXiv
We show that large SUSY phases have no significant effect on the relic density of the lightest supersymmetric particle (LSP). However, they are very significant for the detection rates. We emphasise that the phase of the trilinear coupling increase the direct and indirect detection rates.
View details →Negative / Null Result ReportOpen accessComputer Science
D. Kharzeev, H. Satz, A. Syamtomov et al. · 1996 · arXiv
We extend a recent sum rule calculation for inelastic quarkonium-hadron interactions to realistic parton distribution functions; we also include finite target-mass corrections. Both modifications are shown to have no significant effect on the resulting cross section behaviour but the performed analysis gives useful insights on the sum-rule approach in general.
View details →Negative / Null Result ReportOpen accessComputer Science
N. Metwally, M. Abdel-Aty, M. Sebawe Abdalla · 2008 · arXiv
The speed of quantum computation is investigated through the time evolution of the speed of the orthogonality. The external field components for classical treatment beside the detuning and the coupling parameters for quantum treatment play important roles on the computational speed. It has been shown that the number of photons has no significant effect on the speed of computation. However, it is very sensitive to the variation in both detuning and the interaction coupling parameters.
View details →Negative / Null Result ReportOpen accessPhysics
M. A. G. Maia, C. N. A. Willmer, L. N. da Costa · 1997 · arXiv
We examine the H1 content of spiral galaxies in groups by using a catalog of loose groups of galaxies identified in a magnitude limited sample m < 15.7 spanning the range 8 h to 18 h in right ascension and +9 to +15 in declination. The redshift completeness of the galaxy sample is ~95%. No significant effect of H1 depletion is found, although there may be a hint that the earliest type spirals are slightly deficient.
View details →Negative / Null Result ReportOpen accessEngineering
Nina R Benway, Jonathan L Preston, Asif Salekin et al. · 2023 · arXiv
Mispronunciation detection tools could increase treatment access for speech sound disorders impacting, e.g., /r/. We show age-and-sex normalized formant estimation outperforms cepstral representation for detection of fully rhotic vs. derhotic /r/ in the PERCEPT-R Corpus. Gated recurrent neural networks trained on this feature set achieve a mean test participant-specific F1-score =.81 (σx=.10, med = .83, n = 48), with post hoc modeling showing no significant effect of child age or sex.
View details →Negative / Null Result ReportOpen accessPhysics
P. B. Jones · 2008 · arXiv
Calculations have been made of fall-back disk heating by the pulsar wind as distinct from the soft X-rays emitted by the neutron-star surface. The relation between these heating rates and measured near-infrared fluxes in the K and Ks bands places severe constraints on the inner radii of any fall-back disks that may be present in radio pulsars and in some anomalous X-ray pulsars. The lower limits found are so large that the disks concerned can have no significant effect on pulsar spin-down.
View details →Negative / Null Result ReportOpen accessPhysics
Cristina Bena, Leon Balents · 2001 · arXiv
We study the effect of electron-electron backscattering interactions on spin transport in a quantum wire. Even if these interactions have no significant effect on charge transport, they strongly influence the transport of spin. We use the quantum Boltzmann equation in the collision approximation to derive equations of motion for spin current and magnetization. In the limit of small perturbations from equilibrium, we explain the existence of `precessional' and `diffusive' behaviors. We also discuss the low-temperature non-linear decay of an uniform spin current outside the hydrodynamic regime.
View details →Negative / Null Result ReportOpen accessComputer Science
Tsutomu Kobayashi · 2006 · arXiv
We study the spectrum of gravitational waves generated from inflation in the Randall-Sundrum braneworld. Since the inflationary gravitational waves are of quantum-mechanical origin, the initial configuration of perturbations in the bulk includes Kaluza-Klein quantum fluctuations as well as fluctuations in the zero mode. We show, however, that the initial fluctuations in Kaluza-Klein modes have no significant effect on the late time spectrum, irrespective of the energy scale of inflation and the equation of state parameter in the post-inflationary stage. This is done numerically, using the Wron
View details →Negative / Null Result ReportOpen accessEconomics, Econometrics and Finance
Claudiu Albulescu · 2020 · arXiv
This paper investigates the effect of the novel coronavirus and crude oil prices on the United States (US) economic policy uncertainty (EPU). Using daily data for the period January 21-March 13, 2020, our Autoregressive Distributed Lag (ARDL) model shows that the new infection cases reported at global level, and the death ratio, have no significant effect on the US EPU, whereas the oil price negative dynamics leads to increased uncertainty. However, analyzing the situation outside China, we discover that both new case announcements and the COVID-19 associated death ratio have a positive influe
View details →Negative / Null Result ReportOpen accessPhysics
Takashi Hamana · 1998 · arXiv
Weyl focusing effects on the image magnifications are investigated by using the multiple gravitational lens theory. We focus on the gravitational lensing effects due to the small scale virialized objects, such as galaxies and clusters of galaxies. We consider a simple model of an inhomogeneous universe. The matter distribution in the universe is modeled by randomly distributed isothermal objects. We found that, for the majority of the random lines of sight, the Weyl focusing has no significant effect and the image magnification of a point like source within redshift of 5 is dominated by the Ri
View details →Negative / Null Result ReportOpen accessPhysics
Sarbani Basu, H. M. Antia · 2004 · arXiv
Recent analyses of solar photospheric abundances suggest that the oxygen abundance in the solar atmosphere needs to be revised downwards. In this study we investigate the consequence of this revision on helioseismic analyses of the depth of the solar convection zone and the helium abundance in the solar envelope and find no significant effect. We also find that the revised abundances along with the current OPAL opacity tables are not consistent with seismic data. A significant upward revision of the opacity tables is required to make solar models with lower oxygen abundance consistent with sei
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Thomas M. Breuel · 2015 · arXiv
LSTM (Long Short-Term Memory) recurrent neural networks have been highly successful in a number of application areas. This technical report describes the use of the MNIST and UW3 databases for benchmarking LSTM networks and explores the effect of different architectural and hyperparameter choices on performance. Significant findings include: (1) LSTM performance depends smoothly on learning rates, (2) batching and momentum has no significant effect on performance, (3) softmax training outperforms least square training, (4) peephole units are not useful, (5) the standard non-linearities (tanh a
View details →Negative / Null Result ReportMedicine
Makkar RR, Chakravarty T, Gupta A et al. · 2025 · Journal of the American College of Cardiology
Background In the ACURATE IDE (Safety and Effectiveness Study of ACURATE Valve for Transcatheter Aortic Valve Replacement) randomized controlled trial, ACURATE neo2 failed to show noninferiority to commercially available balloon-expandable…
View details →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.
View details →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
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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
View details →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
View details →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
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