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J. Pantaleone

Publications and source records attributed to J. Pantaleone.

13 recordsLinked to original sources
arXiv2019

A quantitative analysis of the chain fountain

The chain fountain is an entertaining, counter-intuitive phenomenon. When a chain flows up over the edge of a container and then falls to the ground below, it is observed that the top of the chain rises up above the containers edge. Here the steady-state motion of the fountain is analyzed experimentally and theoretically. Measurements are given for the speeds and heights for three different chains and three different distances from the container to the floor. It is shown theoretically that the distance the chain rises above the container is proportional to the force from the container on the chain. The basic physics behind this force is readily understandable and can be illustrated with simple examples. To quantitatively predict the chain's motion a simple model is developed for how the chain interacts with the container. This model shows that a link lifts-off from the container after rotating by a relatively small angle. The model's predictions agree very will with the measurement for the two ball-chains.

physics.class-ph↗
arXiv2019

Understanding how a falling ball chain can be speeded up by impact onto a surface

When a falling ball chain strikes a surface, a tension is created that pulls the chain downward. This causes a downward acceleration that is larger than free-fall, which has been observed by recent experiments. Here a theoretical description of this surprising phenomenon is developed. The equation of motion for the falling chain is derived, and then solved for a general form of the tension. the size of the tension needed to produce the observed motion is relatively small and is explained here as coming from the rotation of a link just above where the chain collides with the surface. This simple model is used to calculate the size of the tension in terms of physically measurable quantities: the length and width of link, the maximum bending angle at a junction, the inclination angle of the surface, and the coefficients of friction and restitution between the chain and the surface. The model's predictions agree with the results of current experiments. New experiments are proposed that can test the model.

physics.class-ph↗
arXiv1998

Getting the Most From Atmospheric Neutrinos

Observations of atmospheric neutrinos by the SuperKamiokande collaboration have demonstrated large mixing of the muon-neutrino. However the present atmospheric neutrino data does not significantly constrain the associated mixing of the electron-neutrino, or the sign of the mass-squared difference. Here we identify the diagnostics for these quantities and they also test the theory of how matter affects neutrino oscillations. These diagnostics are a dip in the sub-GeV muon flux at a zenith angle of 110 degrees, a bump in the electron up-down asymmetry at multi-GeV energies and a bump in the muon-antimuon upward asymmetry.

hep-ph↗
arXiv1997

Comments on Neutrino Tests of Special Relativity

We point out that the assumption of Lorentz noninvariance examined recently by Coleman and Glashow leads to neutrino flavor oscillations which are phenomenologically equivalent to those obtained by assuming the neutrinos violate the principle of equivalence. We then comment on the limits on Lorentz noninvariance which can be derived from solar, atmospheric, and accelerator neutrino experiments.

hep-ph↗
arXiv1995

A Possible Violation of the Equivalence Principle by Neutrinos

We consider the effect of a long range, flavor changing tensor interaction of possible gravitational origin. Neutrino mixing experiments provide the most sensitive probe to date for such forces---testing the equivalence principle at levels below $10^{-20}$. Here we justify and generalize a formalism for describing such effects. The constraints from neutrino mixing experiments on gravitationally induced mixing are calculated. Our detailed analysis of the atmospheric neutrino data confirms a remarkable result: the atmospheric neutrino data implies the same size force as does the solar neutrino data. Additional tests of this suggestive result are discussed.

hep-ph↗
arXiv1995

Possible Revelation of Seesaw Mass Pattern in Solar and Atmospheric Neutrino Data

Assuming the solar and atmospheric neutrino deficits to be due to neutrino oscillations, it is shown that the 3X3 mass matrix spanning the e, mu, and tau neutrinos may have already revealed a seesaw mass pattern. Also, this matrix is the natural reduction of a simple 5X5 seesaw mass matrix with one large scale, the 4X4 reduction of which predicts that a fourth neutrino would mix with the e and mu neutrinos in such a way that oscillations between them may occur just within the detection capability of the LSND (Liquid Scintillator Neutrino Detector) experiment.

hep-ph↗
arXiv1994

Response to Comments on "Neutrino Flavor Evolution Near a Supernova's Core"

In a recent paper I concluded that the neutrino background is important for calculating neutrino flavor evolution in supernovae, and including it weakens the connection between r-process nucleosynthesis and cosmologically relevant neutrino masses. Comments on this paper have been posted to this bulletin board; one by J. Cline and the other by Y.Z. Qian and G.M. Fuller. Here I briefly discuss these Comments and demonstrate that they are inaccurate and ill-considered. No corrections to my paper are necessary.

astro-ph↗
arXiv1993

Constraints on Three-Neutrino Mixing from Atmospheric and Reactor Data

Observations of atmospheric neutrinos are usually analyzed using the simplifying approximation that either \(ν_μ\leftrightarrow ν_τ\) or \(ν_e \leftrightarrow ν_μ\) two-flavor mixing is relevant. Here we instead consider the data using the simplifying approximation that only one neutrino mass scale is relevant. This approximation is the minimal three-flavor notation that includes the two relevant two-flavor approximations. The constraints in the parameter space orthogonal to the usual, two-flavor analyses are studied.

hep-ph↗
arXiv1993

Renormalization of the Neutrino Mass Operator

A small neutrino Majorana mass can arise in the Standard Model as an effective dimension 5 operator. We calculate the renormalization of this operator in the minimal Standard Model and in its two-Higgs-doublet and supersymmetric extensions. Renormalization from the scale of lepton number violation (e.g., the Planck scale or a GUT scale) to the weak scale decreases the strength of this operator by an order of magnitude or more if the top quark and Higgs boson masses are large. Neutrino mixing angles also run with momentum. We show instances where small mixing at a high scale becomes large at the weak scale, and vice versa.

hep-ph↗
arXiv1993

Long Range Forces from the Cosmological Neutrino Background

The cosmological neutrino background will mediate long range forces between objects. For a background of temperature T, the potential decreases as 1/r^5 for r >> 1/T and as 1/r for r << 1/T. These forces have large spin-dependent components. If the neutrino background is nonrelativistic, the long range forces are enhanced by a factor of the inverse neutrino velocity. These long range forces may provide a method for observing the cosmological neutrino background.

hep-ph↗
arXiv1992

Neutrino Mixing due to a Violation of the Equivalence Principle

Massless neutrinos will mix if their couplings to gravity are flavor dependent, i.e., violate the principle of equivalence. Because the gravitational interaction grows with neutrino energy, the solar neutrino problem and the recent atmospheric neutrino data may be simultaneously explained by violations at the level of 1E-14 to 1E-17 or smaller. This possibility is severely constrained by present accelerator neutrino experiments and will be preeminently tested in proposed long baseline accelerator neutrino experiments.

hep-ph↗
arXiv1992

Solar Neutrinos with Three Flavor Mixings

The recent 71Ga solar neutrino observation is combined with the 37Cl and Kamiokande-II observations in an analysis for neutrino masses and mixings. The allowed parameter region is found for matter enhanced mixings among all three neutrino flavors. Distortions of the solar neutrino spectrum unique to three flavors are possible and may be observed in continuing and next generation experiments.

hep-ph↗