Papers by James Pantaleone
The acceleration of a falling coffee filter released from rest is always much less than the free-... more The acceleration of a falling coffee filter released from rest is always much less than the free-fall acceleration of gravity, g. This is true even near the initial release, when the part of the drag force proportional to the velocity is negligible. This small acceleration occurs because there is a part of the drag force that is proportional to the acceleration. This part is called the added mass. The added mass is a large effect for falling coffee filters. Nesting the coffee filters does not change the added mass. The measured value of the added mass from the initial acceleration agrees with the theoretical value calculated for an ideal fluid. In experiments using a motion sensor or video analysis, it is easy to measure both the added mass and the steady-state drag force.
European Journal of Physics, 2022
A sphere moving through a fluid has a larger inertia than one moving through a vacuum. This incre... more A sphere moving through a fluid has a larger inertia than one moving through a vacuum. This increase in the inertia from the fluid is known as the added mass. The added mass has a large effect on the acceleration of the sphere if the sphere has a low density, and if the sphere is near a solid boundary. These effects are studied here by measuring the acceleration due to gravity of beach balls, in air, as they bounce vertically on the floor. The measured accelerations are smaller when the ball is closer to the floor because the added mass is larger there. These measurements are used to calculate the added mass of a sphere as a function of distance from the floor. The results collapse to a curve that is independent of ball size, and generally agrees with the predictions for an ideal fluid.
The renormalization group equations for the general 2 by 2, complex, neutrino mass matrix are sho... more The renormalization group equations for the general 2 by 2, complex, neutrino mass matrix are shown to have exact, analytic solutions. Simple formulas are given for the physical mixing angle, complex phase and mass ratio in terms of their initial values and the energy scales. We also establish a (complex) renormalization invariant relating these parameters. The qualitative features of the physical parameters' renormalization are clearly illustrated in vector field plots. In both the SM and MSSM, maximal mixing is a saddle point.
Nasa Sti Recon Technical Report N, Dec 1, 1992
Langmuir, 2016
Here we grow chemical gardens using a novel, quasi two-dimensional, experimental configuration. B... more Here we grow chemical gardens using a novel, quasi two-dimensional, experimental configuration. Buoyant calcium chloride solution is pumped onto the surface of sodium silicate solution. The solutions react to form a precipitation structure on the surface. Initially, an open channel forms that grows in a spiral. This transitions to radially spreading and branching fingers, which typically oscillate in transparency as they grow. The depth of the radial spreading, and the fractal dimension of the finger growth, are surprisingly robust, being insensitive to the pumping rate. The curvature of the channel membrane and the depth of the radially spreading solution can be explained in terms of the solution densities and the interfacial tension across the semipermeable membrane. These unusually beautiful structures provide new insights into the dynamics of precipitation structures and may lead to new technologies where structures are grown instead of assembled.
Phys Rev D, Mar 30, 1997
We point out that the assumption of Lorentz noninvariance examined recently by Coleman and Glasho... more 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.
Chaos (Woodbury, N.Y.), 2015
A popular playground for studying chemo-hydrodynamic patterns and instabilities is chemical garde... more A popular playground for studying chemo-hydrodynamic patterns and instabilities is chemical gardens, also known as silicate gardens. In these systems, complex structures spontaneously form, driven by buoyant forces and either osmotic or mechanical pumps. Here, we report on systems that differ somewhat from classical chemical gardens in that the membranes are much more deformable and soluble. These properties lead to structures that self-construct and evolve in new ways. For example, they exhibit the formation of chemical balloons, a new growth mechanism for tubes, and also the homologous shrinking of these tubes. The stretching mechanism for the membranes is probably different than for other systems by involving membrane "self-healing." Other unusual properties are osmosis that sometimes occurs out of the structure and also small plumes that flow away from the structure, sometimes upwards, and sometimes downwards. Mathematical models are given that explain some of the obse...
Physics Letters B, 1989
We consider the phenomenological consequences of a recently proposed model with four lepton gener... more We consider the phenomenological consequences of a recently proposed model with four lepton generations such that the three known neutrinos have radiatively induced Majorana masses. Mixing among generations in the presence of a heavy fourth neutrino necessitates a reevaluation of the usual experimental tests of the standard model. One interesting possibility is to have a "~ lifetime longer than predicted by the standard three-generation model. Another is to have neutrino masses and mixing angles in the range needed for a natural explanation of the solar-neutrino puzzle in terms of the Mikbeyev-Smirnov-Wolfenstein effect.
Physics Letters B, 1991
The effective field for a Dirac neutrino in a background of matter is derived. As an application,... more The effective field for a Dirac neutrino in a background of matter is derived. As an application, the cross section for helicity flip in neutrino-nucleus scattering is calculated. It is found that the matter background is negligible when the neutrino momentum is much larger than the matter induced potential. The implications of these results for a 17 keV neutrino are discussed.
Physics Letters B, 1992
Abstract New ranges of neutrino oscillation parameters can be probed by sending accelerator produ... more Abstract New ranges of neutrino oscillation parameters can be probed by sending accelerator produced ν μ to large neutrino detectors thousands of kilometers away. Since the neutrino propagation is through the Earth, the ν e −ν τ mixing can be enhanced by matter effects. Then a neutrino coupled dominantly to the ν τ , with a mass squared of 10 −3 −10 −1 eV 2 , may most easily be observed by a ν e appearance experiment.
Physical review D: Particles and fields, 1995
Assuming the solar and atmospheric neutrino deficits to be due to neutrino oscillations, it is sh... more Assuming the solar and atmospheric neutrino deficits to be due to neutrino oscillations, it is shown that the 3 × 3 mass matrix spanning ν e , ν µ , and ν τ may have already revealed a seesaw mass pattern. Also, this matrix is the natural reduction of a simple 5 × 5 seesaw mass matrix with one large scale, the 4 × 4 reduction of which predicts that a fourth neutrino would mix with ν e and ν µ in such a way that ν µ → ν e oscillations may occur just within the detection capability of the LSND (Liquid Scintillator Neutrino Detector) experiment.
Physical review D: Particles and fields, Jan 15, 1991
... 65, 3084 (1990). [14] A. Suzuki, M. Mori, K. Numata, and Y. Oyama, Phys. Rev. D 43, 3557 (199... more ... 65, 3084 (1990). [14] A. Suzuki, M. Mori, K. Numata, and Y. Oyama, Phys. Rev. D 43, 3557 (1991). [15] KS Babu and R. Mohapatra, Phys. Rev. D 43, 2278 (1991). [16] RS Raghavan, in Proceedings of the 25th International Conference on High Energy Physics [2], p. 482. ...
Uploads
Papers by James Pantaleone