34,001 reputation
347115
bio website inspirehep.net/…
location Duchy of Grand Fenwick
age 43
visits member for 3 years, 10 months
seen 3 hours ago

Experimental nuclear and particle physicist. These days I'm teaching, but I've spent a lot of time on nucleon structure in fixed target electron scattering and neutrino oscillations using reactors and beam sources.


4h
comment Is one large bomb more powerful than a series of small bombs? Why?
Conversely, many small bombs are generally ineffective against hardened targets for which you want either a designed penetrator or a really high pressure device. Which is why the question is still too much of a mess to be answered.
4h
comment Is one large bomb more powerful than a series of small bombs? Why?
I'm afraid even the most recent definition is not much use. It really matters whether you are trying to, say, open a bank vault, rapidly remove some unwanted sandstone from a road-cut, or (alas) kill a bunch of people in a urban environment. Different tools for different jobs.
5h
comment How is it possible to accelerate a neutron?
Of course you can generate a very modest force in the Stern-Gerlach approach, but it's not worth anything for making a beam.
1d
comment Has magnetism been experimentally demonstrated at the quantum level?
Search terms: fine structure; hyper-fine structure; quantum hall effect; SQUIDs; etc.
1d
awarded  Enlightened
1d
awarded  Nice Answer
1d
comment A basic relation in spherical coordinates
Have you tried taking the differential of both sides? In any case this is a pure math question.
1d
comment Is there any defect in Rutherford's atomic model according to quantum theory?
It has all the failings of the Bohr model plus the inability to explain the discrete atomic spectra or why the electrons don't spiral in.
1d
comment Detecting negative energy products in particle accelerators
The oscillation observable is $\left( \Delta m \right)^2$: the square of the differences of masses. There are other ways to attack the mass problem that get at $m_\nu$ directly, though they are not yet at the necessary precision.
1d
revised Has gravity ever been experimentally measured between two atoms?
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1d
comment Has gravity ever been experimentally measured between two atoms?
Powerhouse answer, and nice coverage of parity-violating weak observations.
1d
comment Detecting negative energy products in particle accelerators
Using a symmetric error computation near a boundary is an error. People who understand the statistics of neutrino mass measurement experiments use an appropriate error measure that respect the boundary--Feldman-Cousins is usual in neutrino physics right now.
1d
revised Electron electric field
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revised Electron electric field
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1d
answered Electron electric field
1d
comment Is there a machine readable format of the data tables in Particle Data Group PDFs?
It's worth noting these that the format used for computer readable data in bulk is the Evaluated Nuclear Data File (ENDF) (a white-space delimenated columnar textfile). Available from several sources as there are multiple evaluating bodies (e.g. the Japanese have one that puts out the JENDFs). The stuff that appears in the PDG summaries are the bits that an experimenter needs in order to know which what to worry about in designing a experiment or equivalently which ENDFs to bother with in simulation.
2d
awarded  Enlightened
2d
comment Detecting negative energy products in particle accelerators
@ACuriousMind "Berkeleyian" is a term of art from philosophy. It denotes a particular school of thought, and if my long-ago intro to philosophy does not fail me would be named after Bishop Berkeley. I seem to recall that he held that the physical world has a real and on-going physical existence because God is keeping tabs on it. Or something like that. To be contrasted with the guys who were busy wondering if their sensorium could be deceiving them.
2d
comment Detecting negative energy products in particle accelerators
You can only measure on-shell particles. Saying that is theory neglects the fact that the theory was developed from data. Off-shell particles may or may not be "real" depending on your level of Platonic belief, but what they are is terms in a series expansion of the path-integral, not observables.
2d
awarded  Nice Answer