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242158
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location Greece
age 75
visits member for 4 years, 4 months
seen 25 mins ago

Retired experimental particle physicist.

The picture is a fayum . It looks like aunts and cousins of mine :).


19m
answered Electron-Positron Annihilation: How is charge conserved at the verticies?
4h
comment Why do only heavy radioactive elements perform fission or fusion?
Radiation damage is complicated issue, and not my specialty, to write stories about. I already gave a link above . Here is a talk teachers.web.cern.ch/teachers/archiv/HST2002/feynman/… , in page 7 it shows the cotnribution of nuclear processes to the radiation damage. Here are proposals to use induced fission to make radioactive waste from nuclear reactors harmless. irs.uni-hannover.de/uploads/tx_tkpublikationen/drshams.pdf
7h
comment Can a proton be trapped by eight other protons?
@CuriousOne for a metastable state one would need a complete solution
7h
comment Neutron antineutron reaction documentation
@MiladP. Yes, the five pions have in sum charge 1, the charge of the proton on which the antineutron annihilated. Charge exchange means that the antiproton exchanges its charge with the proton, it becomes an antineutron and the proton becomes a neutron: teachers.web.cern.ch/teachers/archiv/HST2002/feynman/…
7h
comment Can a proton be trapped by eight other protons?
@CuriousOne I am just arguing from the symmetry of the problem.
10h
comment Can a proton be trapped by eight other protons?
in a completely, but completely symmetric system, it can sit there. In the middle in a metastable position, the slightest asymmetry, a cosmic muon passing through for example, will send it hurdling out, between the field lines against the interaction with the muon, accelerated as it is leaving.
11h
comment Why do planets move in fixed orbits?
yes, it is a steady v for the rotating stone other wise the system will imbalance and the stone may hit you.
11h
comment Why do planets move in fixed orbits?
what coilkid said. you are applying the force/work against the centrifugal force
12h
answered Why do only heavy radioactive elements perform fission or fusion?
12h
comment Why do planets move in fixed orbits?
If you rotate a stone on a string what prevents it from hitting your hand?
12h
comment Quantization in Black Body Radiation
this link makes it clear : hyperphysics.phy-astr.gsu.edu/hbase/mod6.html#c6 it is maxwell's equations that have to be used to solve for radiation and classically they come out into the ultraviolet catastrophy.
21h
comment Can a microwave oven induce an accumulation of static charge in food?
have a look here gizmodo.com/… "Sometimes the electromagnetic field within the microwave can get a little mixed up and generate small arcs of electrical discharge. This can be caused by innocuous items like carrots (when grown in mineral rich soil) and hot dogs (when the salt and additives aren't properly mixed). " So electric fields do build up possibly because of inhomogeneities in the distribution of salts or whatever within the organic material.
23h
comment Why there is no mention of Archimedes Principle in whole Fluid Mechanics?
this seems to be a course in fluid dynamics and statics physics.usyd.edu.au/~jbryant/Fluids/Fluidslect3.pdf. A principle is in fluid statics.
1d
comment If mesons were stable could they form atoms?
@fqq edited , thanks
1d
revised If mesons were stable could they form atoms?
expanded after comment
1d
answered If mesons were stable could they form atoms?
1d
comment Can dark matter be converted to dark energy?
have you read and understood the wiki article ? en.wikipedia.org/wiki/Dark_energy
1d
comment Particle Physics Decay Question - Eta Prime Decay Parity/Angular Momentum Conservation
There is G parity conservation as a generalization of the statement by Paganini en.wikipedia.org/wiki/G-parity
1d
comment Particle Physics Decay Question - Eta Prime Decay Parity/Angular Momentum Conservation
did you check for Isospin conservation? hyperphysics.phy-astr.gsu.edu/hbase/particles/parint.html
1d
comment Doesn't Schrodinger's Cat depend on whether there's a quantum/classical boundary?
@user46759 We use classical measurements because our detectors are bulk matter and classical mechanics and electrodynamics describe macroscopic effects. Studying tracks in bubble chambers macroscopically gives us crossections that can only be described by quantum mechanics. The cat in this example is a detector, and conforms due to bulk matter to classical equations. It will be alive until it is dead. Once the quantum mechanical probability release poison it is dead.