29,752 reputation
33994
bio website inspirehep.net/…
location Duchy of Grand Fenwick
age 43
visits member for 3 years, 5 months
seen 6 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.


Aug
15
comment Are coffee's properties different enough from water's to cause increased spillage while walking?
@LanceLafontaine Not necessarily. That has the smell of a "fun" paper, and coffee may have been used because it let them write an amusing story for publication in a serious venue. That kind of things gets people's attention. Think Alpher, Bethe, Gamow.
Aug
15
comment Are coffee's properties different enough from water's to cause increased spillage while walking?
Without a whit of evidence I would suspect surface tension or viscosity before density. // and "Go, Gauchos! //// spent a little time at U Can Study Buzzed
Aug
15
comment How are the masses of unstable elementary particles measured?
The geometry of the helix really only gives you the momentum-to-charge ratio, then you get both the total energy and the charge by calorimetry along the track (the energy loss for "massive" particles is a function of $q\gamma\beta$) and so shows a experimentally useful pattern.
Aug
15
comment Phase space suppression
Hmmm...the "related" question finder has failed us here. This is nearly a duplicate of What does the concept of phase space mean in particle physics?, and you can find a discussion of how the available phase space affects a class of reaction in my answer to Why is the (free) neutron lifetime so long?.
Aug
15
comment How are the masses of unstable elementary particles measured?
Higgs has a lot of possible channels. I believe that only gamma--gamma and 2-weak boson channels were used for the recent announcement. In those cases there are some missing particles, so more tricks have to be played based on the assumed decay physics. The night of the announcement I could have interpreted it all for you, but it is not my subfield and I have forgotten much of what I heard.
Aug
14
revised How are the masses of unstable elementary particles measured?
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Aug
14
revised How are the masses of unstable elementary particles measured?
added 115 characters in body
Aug
14
revised How are the masses of unstable elementary particles measured?
added 475 characters in body
Aug
14
comment How are the masses of unstable elementary particles measured?
Yes the threshold approach can be extended to very unstable particles, but the production rate for the Higgs is too small by far. The Tevatron was chasing it for more than a decade, but didn't have the cross-section.
Aug
14
comment How are the masses of unstable elementary particles measured?
I;ve stripped the [accelerator-physics] tag as that usual means the behavior of the beam and energy imparting mechanisms rather that physics done with the beam. And I see that there are many such misuses. Off to meta to poll the users.
Aug
14
revised How are the masses of unstable elementary particles measured?
edited tags
Aug
14
comment How are the masses of unstable elementary particles measured?
The fun part here is getting high energy photons with well known energies. The search term is "photon tagger" or "photon tagging". A very cool business in and of itself. Thresholds are generally not used for very heavy particles because the rate at threshold is vanishing.
Aug
14
answered How are the masses of unstable elementary particles measured?
Aug
14
answered Wave Function Statistical Interpretation vs Oscillation Interpretation
Aug
14
answered Can the equation $v=\lambda f$ be made true even for non sinusoidal waves?
Aug
14
answered How can there be heat in a vacuum?
Aug
14
comment Is it possible to build an instrument which can travel faster than light?
For the purposes of these types of questions "the speed of light" universally means "the speed of light in vacuum". When we wish to discuss, for instance, Cerenkov radiation, we say "the speed of light in the medium" for clarity.
Aug
14
comment Is it possible to build an instrument which can travel faster than light?
@RodyOldenhuis There is a point of view that failure to even try to find the many existing questions on the site (not by searching, mind you, but just by looking at the similar titles that come up when you type "faster than light" into the title of the ask a question page) makes this a bad question, and indicative of a user who may continue to expect us to do his or her work. Indeed, the feeling of the Stack Exchange management has moved steadily from an initial position very much like your to a rather tough position that failure to do some basic homework is unacceptable.
Aug
14
reviewed Approve suggested edit on can sound travel is space?
Aug
13
comment Relation between Electric and magnetic fields
What kind of answer do you expect to "How is this possible?"? Seriously, why do you think it wouldn't be "possible"? Moreover, if you've taken a intro course then you should be aware that this is an experimental fact, right? No amount of philosophy can trump that. That which is, is.