J. Gruenwald - Academia.edu (original) (raw)

Papers by J. Gruenwald

Scientific reports, Mar 10, 2024

Research Square (Research Square), Nov 29, 2023

International Journal of Modern Physics A

A 5th force coupling to baryon number [Formula: see text] has been proposed to account for the co... more A 5th force coupling to baryon number [Formula: see text] has been proposed to account for the correlations between the acceleration differences [Formula: see text] of the samples studied in the Eötvös experiment, and the corresponding differences in the baryon-to-mass ratios [Formula: see text]. To date the Eötvös results have not been supported by modern experiments. Here, we investigate the phenomenological implications of a possible magnetic analog [Formula: see text] of the conventional 5th force electric field, [Formula: see text], arising from the Earth’s rotation. We demonstrate that, in the presence of couplings proportional to [Formula: see text], both the magnitude and direction of a possible 5th force field could be quite different from what would otherwise be expected and warrants further investigation.

Thesis Purdue University 1976 Source Dissertation Abstracts International Volume 37 10 Section B Page 5162, Dec 1, 1976

Abstract not availabl

Physics of Fluids

The Riemann problem is fundamental to most computational fluid dynamics (CFD) codes for simulatin... more The Riemann problem is fundamental to most computational fluid dynamics (CFD) codes for simulating compressible flows. The time to obtain the exact solution to this problem for real fluids is high because of the complexity of the fluid model, which includes the equation of state; as a result, approximate Riemann solvers are used in lieu of the exact ones, even for ideal gases. We used fully connected feedforward neural networks to find the solution to the Riemann problem for calorically imperfect gases, supercritical fluids, and high explosives and then embedded these network into a one-dimensional finite volume CFD code. We showed that for real fluids, the neural networks can be more than five orders of magnitude faster than the exact solver, with prediction errors below 0.8%. The same neural networks embedded in a CFD code yields very good agreement with the overall exact solution, with a speed-up of three orders of magnitude with respect to the same CFD code that use the exact Ri...

We have reanalyzed data obtained by Potter in a 1923 experiment aimed at testing whether the acce... more We have reanalyzed data obtained by Potter in a 1923 experiment aimed at testing whether the accelerations of test masses in the Earth’s gravitational field are independent of their compositions. Although Potter concludes that the accelerations of his samples compared to a brass standard were individually consistent with a null result, we show that the pattern formed from a combined plot of all of his data suggests the presence of a fifth force coupling to baryon number.

arXiv: High Energy Physics - Phenomenology, 2020

Indications of a possible composition-dependent fifth force, based on a reanalysis of the E\&quot... more Indications of a possible composition-dependent fifth force, based on a reanalysis of the E\"{o}tv\"{o}s experiment, have not been supported by a number of modern experiments. Here, we argue that searching for a composition-dependent fifth force necessarily requires data from experiments in which the acceleration differences of three or more independent pairs of test samples of varying composition are determined. We suggest that a new round of fifth-force experiments is called for, in each of which three or more different pairs of samples are compared.

arXiv: Instrumentation and Methods for Astrophysics, 2017

Recent observations of changes in radioactive decay rates associated with the annual variation of... more Recent observations of changes in radioactive decay rates associated with the annual variation of the Earth-Sun distance, with solar rotation, and particularly with solar storms, suggest that radioactive decay rates may be responding to small changes in ambient neutrino/antineutrino flux. We propose to build a network of detectors (NU-SETI), based on monitoring radioactive decays, to search for pulsed signals from an extra-terrestrial source carried by neutrinos or antineutrinos.

Physical Review D, 1976

The process gammagammagamma$gamma$ YieldsYieldsYields ($pi$$sup 0$ or eta) YieldsYieldsYields nununu anti nununu, which can be in... more The process gammagammagamma$gamma$ YieldsYieldsYields ($pi$$sup 0$ or eta) YieldsYieldsYields nununu anti nununu, which can be induced by helicity-flipping scalar and/or pseudoscalar neutral currents, may be of significance in various astrophysical processes. For temperatures of order 10$sup 11$ sup0sup 0sup0K, the conversion rate into neutrinos via this mechanism is enormous; hence, this process may be important in the understanding of the early universe and of supernovas. (AIP)

Astroparticle Physics, 2010

Jenkins and Fischbach (Astroparticle Physics, 31, 407, 2009) have recently found evidence for flu... more Jenkins and Fischbach (Astroparticle Physics, 31, 407, 2009) have recently found evidence for fluctuations in the decay rates of radioactive isotopes in association with solar flares. Jenkins et al. (Astroparticle Physics, 32, 42, 2010) have also found strong evidence for annual variations in measurements of decay rates acquired at the Brookhaven National Laboratory (BNL) and at the Physikalisch-Technische Bundesanstalt (PTB) in Germany. If these claims are confirmed, they pose important questions in particle physics and in solar physics, with the intriguing possibility that such measurements may lead to procedures for predicting the occurrence of some solar flares. The purpose of this presentation is to discuss these questions. The strongest feature of the variability of isotopic decay rates is an annual variation in both BNL and PTB data. The phases of these variations rule out the possibility that they are due either to the annual variation in temperature or to the annual variation in Sun-Earth distance. However, we found some time ago that the solar neutrino flux, as measured at Earth, is influenced not only by the varying Sun-Earth distance, but also by the variation in the heliospheric latitude of the Sun-Earth vector (Sturrock,Walther, and Wheatland, Astrophys. J., 507, 978, 1998). The phases of the annual variation in the BNL and PTB data are consistent with the combined effect of varying Sun-Earth distance and varying heliospheric latitude. This result suggests that the decay rates may be influenced by solar neutrinos. This interpretation would require a revision of neutrino physics. In order to check this hypothesis, it would clearly be desirable to be able to compare decay data with neutrino data. The difficulty is that the decay-rate variations amount to only a few parts in 10,000. This is far too small a fraction to be detectable in neutrino data. However, we have recently found that there is a close association between variations in the solar neutrino flux and variations in solar irradiance. Hence we may, with caution, use irradiance data as a proxy for neutrino data. This has the advantage that irradiance data has been measured several times a day with very high accuracy for over thirty years. We shall present recent results on the comparison of decay data and irradiance data, and comment on possible processes that might explain these associations. This work was supported by the National Science Foundation through grant AST-0607572.

We report the results of an experiment conducted near the High Flux Isotope Reactor of Oak Ridge ... more We report the results of an experiment conducted near the High Flux Isotope Reactor of Oak Ridge National Laboratory, designed to address the question of whether a flux of reactor-generated electron antineutrinos can alter the rates of weak nuclear interaction-induced decays for Mn-54, Na-22, and Co-60. This experiment, while quite sensitive, cannot exclude perturbations less than one or two parts in 10410^4104 in beta\betabeta decay (or electron capture) processes, in the presence of an antineutrino flux of 3times10123\times 10^{12}3times1012 cm$^{-2}$ s$^{-1}$. The present experimental methods are applicable to a wide range of isotopes. Improved sensitivity in future experiments may be possible if we can understand and reduce the dominant systematic uncertainties.

We discuss how high energy neutrino communications could be synchronized to large-scale astrophys... more We discuss how high energy neutrino communications could be synchronized to large-scale astrophysical events either in addition to or instead of electromagnetic signals.

Applied Radiation and Isotopes

We report the results of an experiment conducted near the High Flux Isotope Reactor of Oak Ridge ... more We report the results of an experiment conducted near the High Flux Isotope Reactor of Oak Ridge National Laboratory, designed to address the question of whether a flux of reactor-generated electron antineutrinos (ν¯e) can alter the rates of weak nuclear interaction induced decays of 54Mn, 22Na, and 60Co. This experiment has small statistical errors but, when systematic uncertainties are included, has null results. Perturbations greater than one part in 104 are excluded at 95% confidence level in β± decay and electron capture processes, in the presence of an antineutrino flux of 3 × 1012 cm-2s-1. The present experimental methods are applicable to a wide range of radionuclides. Improved sensitivity in future experiments can be anticipated as we continue to better understand and reduce the dominant systematic uncertainties.

Astroparticle Physics

Abstract Following recent indications that several radioactive isotopes show fluctuating decay ra... more Abstract Following recent indications that several radioactive isotopes show fluctuating decay rates which may be influenced by solar activity, we present findings from a 2 year period of data collection on 54Mn. Measurements were recorded hourly from a 1 μCi sample of 54Mn monitored from January 2010–December 2011. A series of signal-detection algorithms determine regions of statistically significant fluctuations in decay behaviour from the expected exponential form. The 239 decay flags identified during this interval were compared to daily distributions of multiple solar indices, generated by noaa , which are associated with heightened solar activity. The indices were filtered to provide a list of the 413 strongest events during a coincident period. We find that 49% of the strongest solar events are preceded by at least 1 decay flag within a 48 h interval, and 37% of decay flags are followed by a reported solar event within 48 h. These results are significant at the 0.9σ and 2.8σ levels respectively, based on a comparison to results obtained from a shuffle test, in which the decay measurements were randomly shuffled in time 10,000 times. We also present results from a simulation combining constructed data reflecting 10 sites which compared and filtered decay flags generated from all sites. The results indicate a potential 35% reduction in the false positive rate in going from 1 to 10 sites. By implication, the improved statistics attest to the benefit of analysing data from a larger number of geographically distributed sites in parallel.

arXiv: Nuclear Experiment, 2020

Knowledge of the decay rates (or half-lives) of radioisotopes is critical in many fields, includi... more Knowledge of the decay rates (or half-lives) of radioisotopes is critical in many fields, including medicine, archeology, and nuclear physics, to name just a few. Central to the many uses of radioisotopes is the belief that decay rates are fundamental constants of nature, just as the masses of the radioisotopes themselves are. Recently, the belief that decay rates are fundamental constants has been called into question following the observation of various reported anomalies in decay rates, such as apparent periodic variations. The purpose of this bibliography is to collect in one place the relevant literature on both sides of this issue in the expectation that doing so will deepen our understanding of the available data.

Scientific reports, Mar 10, 2024

Research Square (Research Square), Nov 29, 2023

International Journal of Modern Physics A

A 5th force coupling to baryon number [Formula: see text] has been proposed to account for the co... more A 5th force coupling to baryon number [Formula: see text] has been proposed to account for the correlations between the acceleration differences [Formula: see text] of the samples studied in the Eötvös experiment, and the corresponding differences in the baryon-to-mass ratios [Formula: see text]. To date the Eötvös results have not been supported by modern experiments. Here, we investigate the phenomenological implications of a possible magnetic analog [Formula: see text] of the conventional 5th force electric field, [Formula: see text], arising from the Earth’s rotation. We demonstrate that, in the presence of couplings proportional to [Formula: see text], both the magnitude and direction of a possible 5th force field could be quite different from what would otherwise be expected and warrants further investigation.

Thesis Purdue University 1976 Source Dissertation Abstracts International Volume 37 10 Section B Page 5162, Dec 1, 1976

Abstract not availabl

Physics of Fluids

The Riemann problem is fundamental to most computational fluid dynamics (CFD) codes for simulatin... more The Riemann problem is fundamental to most computational fluid dynamics (CFD) codes for simulating compressible flows. The time to obtain the exact solution to this problem for real fluids is high because of the complexity of the fluid model, which includes the equation of state; as a result, approximate Riemann solvers are used in lieu of the exact ones, even for ideal gases. We used fully connected feedforward neural networks to find the solution to the Riemann problem for calorically imperfect gases, supercritical fluids, and high explosives and then embedded these network into a one-dimensional finite volume CFD code. We showed that for real fluids, the neural networks can be more than five orders of magnitude faster than the exact solver, with prediction errors below 0.8%. The same neural networks embedded in a CFD code yields very good agreement with the overall exact solution, with a speed-up of three orders of magnitude with respect to the same CFD code that use the exact Ri...

We have reanalyzed data obtained by Potter in a 1923 experiment aimed at testing whether the acce... more We have reanalyzed data obtained by Potter in a 1923 experiment aimed at testing whether the accelerations of test masses in the Earth’s gravitational field are independent of their compositions. Although Potter concludes that the accelerations of his samples compared to a brass standard were individually consistent with a null result, we show that the pattern formed from a combined plot of all of his data suggests the presence of a fifth force coupling to baryon number.

arXiv: High Energy Physics - Phenomenology, 2020

Indications of a possible composition-dependent fifth force, based on a reanalysis of the E\&quot... more Indications of a possible composition-dependent fifth force, based on a reanalysis of the E\"{o}tv\"{o}s experiment, have not been supported by a number of modern experiments. Here, we argue that searching for a composition-dependent fifth force necessarily requires data from experiments in which the acceleration differences of three or more independent pairs of test samples of varying composition are determined. We suggest that a new round of fifth-force experiments is called for, in each of which three or more different pairs of samples are compared.

arXiv: Instrumentation and Methods for Astrophysics, 2017

Recent observations of changes in radioactive decay rates associated with the annual variation of... more Recent observations of changes in radioactive decay rates associated with the annual variation of the Earth-Sun distance, with solar rotation, and particularly with solar storms, suggest that radioactive decay rates may be responding to small changes in ambient neutrino/antineutrino flux. We propose to build a network of detectors (NU-SETI), based on monitoring radioactive decays, to search for pulsed signals from an extra-terrestrial source carried by neutrinos or antineutrinos.

Physical Review D, 1976

The process gammagammagamma$gamma$ YieldsYieldsYields ($pi$$sup 0$ or eta) YieldsYieldsYields nununu anti nununu, which can be in... more The process gammagammagamma$gamma$ YieldsYieldsYields ($pi$$sup 0$ or eta) YieldsYieldsYields nununu anti nununu, which can be induced by helicity-flipping scalar and/or pseudoscalar neutral currents, may be of significance in various astrophysical processes. For temperatures of order 10$sup 11$ sup0sup 0sup0K, the conversion rate into neutrinos via this mechanism is enormous; hence, this process may be important in the understanding of the early universe and of supernovas. (AIP)

Astroparticle Physics, 2010

Jenkins and Fischbach (Astroparticle Physics, 31, 407, 2009) have recently found evidence for flu... more Jenkins and Fischbach (Astroparticle Physics, 31, 407, 2009) have recently found evidence for fluctuations in the decay rates of radioactive isotopes in association with solar flares. Jenkins et al. (Astroparticle Physics, 32, 42, 2010) have also found strong evidence for annual variations in measurements of decay rates acquired at the Brookhaven National Laboratory (BNL) and at the Physikalisch-Technische Bundesanstalt (PTB) in Germany. If these claims are confirmed, they pose important questions in particle physics and in solar physics, with the intriguing possibility that such measurements may lead to procedures for predicting the occurrence of some solar flares. The purpose of this presentation is to discuss these questions. The strongest feature of the variability of isotopic decay rates is an annual variation in both BNL and PTB data. The phases of these variations rule out the possibility that they are due either to the annual variation in temperature or to the annual variation in Sun-Earth distance. However, we found some time ago that the solar neutrino flux, as measured at Earth, is influenced not only by the varying Sun-Earth distance, but also by the variation in the heliospheric latitude of the Sun-Earth vector (Sturrock,Walther, and Wheatland, Astrophys. J., 507, 978, 1998). The phases of the annual variation in the BNL and PTB data are consistent with the combined effect of varying Sun-Earth distance and varying heliospheric latitude. This result suggests that the decay rates may be influenced by solar neutrinos. This interpretation would require a revision of neutrino physics. In order to check this hypothesis, it would clearly be desirable to be able to compare decay data with neutrino data. The difficulty is that the decay-rate variations amount to only a few parts in 10,000. This is far too small a fraction to be detectable in neutrino data. However, we have recently found that there is a close association between variations in the solar neutrino flux and variations in solar irradiance. Hence we may, with caution, use irradiance data as a proxy for neutrino data. This has the advantage that irradiance data has been measured several times a day with very high accuracy for over thirty years. We shall present recent results on the comparison of decay data and irradiance data, and comment on possible processes that might explain these associations. This work was supported by the National Science Foundation through grant AST-0607572.

We report the results of an experiment conducted near the High Flux Isotope Reactor of Oak Ridge ... more We report the results of an experiment conducted near the High Flux Isotope Reactor of Oak Ridge National Laboratory, designed to address the question of whether a flux of reactor-generated electron antineutrinos can alter the rates of weak nuclear interaction-induced decays for Mn-54, Na-22, and Co-60. This experiment, while quite sensitive, cannot exclude perturbations less than one or two parts in 10410^4104 in beta\betabeta decay (or electron capture) processes, in the presence of an antineutrino flux of 3times10123\times 10^{12}3times1012 cm$^{-2}$ s$^{-1}$. The present experimental methods are applicable to a wide range of isotopes. Improved sensitivity in future experiments may be possible if we can understand and reduce the dominant systematic uncertainties.

We discuss how high energy neutrino communications could be synchronized to large-scale astrophys... more We discuss how high energy neutrino communications could be synchronized to large-scale astrophysical events either in addition to or instead of electromagnetic signals.

Applied Radiation and Isotopes

We report the results of an experiment conducted near the High Flux Isotope Reactor of Oak Ridge ... more We report the results of an experiment conducted near the High Flux Isotope Reactor of Oak Ridge National Laboratory, designed to address the question of whether a flux of reactor-generated electron antineutrinos (ν¯e) can alter the rates of weak nuclear interaction induced decays of 54Mn, 22Na, and 60Co. This experiment has small statistical errors but, when systematic uncertainties are included, has null results. Perturbations greater than one part in 104 are excluded at 95% confidence level in β± decay and electron capture processes, in the presence of an antineutrino flux of 3 × 1012 cm-2s-1. The present experimental methods are applicable to a wide range of radionuclides. Improved sensitivity in future experiments can be anticipated as we continue to better understand and reduce the dominant systematic uncertainties.

Astroparticle Physics

Abstract Following recent indications that several radioactive isotopes show fluctuating decay ra... more Abstract Following recent indications that several radioactive isotopes show fluctuating decay rates which may be influenced by solar activity, we present findings from a 2 year period of data collection on 54Mn. Measurements were recorded hourly from a 1 μCi sample of 54Mn monitored from January 2010–December 2011. A series of signal-detection algorithms determine regions of statistically significant fluctuations in decay behaviour from the expected exponential form. The 239 decay flags identified during this interval were compared to daily distributions of multiple solar indices, generated by noaa , which are associated with heightened solar activity. The indices were filtered to provide a list of the 413 strongest events during a coincident period. We find that 49% of the strongest solar events are preceded by at least 1 decay flag within a 48 h interval, and 37% of decay flags are followed by a reported solar event within 48 h. These results are significant at the 0.9σ and 2.8σ levels respectively, based on a comparison to results obtained from a shuffle test, in which the decay measurements were randomly shuffled in time 10,000 times. We also present results from a simulation combining constructed data reflecting 10 sites which compared and filtered decay flags generated from all sites. The results indicate a potential 35% reduction in the false positive rate in going from 1 to 10 sites. By implication, the improved statistics attest to the benefit of analysing data from a larger number of geographically distributed sites in parallel.

arXiv: Nuclear Experiment, 2020

Knowledge of the decay rates (or half-lives) of radioisotopes is critical in many fields, includi... more Knowledge of the decay rates (or half-lives) of radioisotopes is critical in many fields, including medicine, archeology, and nuclear physics, to name just a few. Central to the many uses of radioisotopes is the belief that decay rates are fundamental constants of nature, just as the masses of the radioisotopes themselves are. Recently, the belief that decay rates are fundamental constants has been called into question following the observation of various reported anomalies in decay rates, such as apparent periodic variations. The purpose of this bibliography is to collect in one place the relevant literature on both sides of this issue in the expectation that doing so will deepen our understanding of the available data.