2,743 research outputs found
Is G a conversion factor or a fundamental unit?
By using fundamental units c, h, G as conversion factors one can easily
transform the dimensions of all observables. In particular one can make them
all ``geometrical'', or dimensionless. However this has no impact on the fact
that there are three fundamental units, G being one of them. Only experiment
can tell us whether G is basically fundamental.Comment: 2 page
Do Present LEP Data Provide Evidence for Electroweak Corrections?
The Born approximation, based on instead of
, reproduces all electroweak precision measurements within their
accuracy. The low upper limits for the genuinely electroweak
corrections constitute one of the major achievements of LEP. The astonishing
smallness of these corrections results from the cancellation of a large
positive contribution from the heavy top quark and large negative contributions
from all other virtual particles. It is precisely the non-observation of
electroweak radiative corrections that places stringent upper and lower limits
on the top mass.Comment: 12 pages, preprint CERN-TH.6943/9
Critical velocities and in general theory of relativity
We consider a few thought experiments of radial motion of massive particles
in the gravitational fields outside and inside various celestial bodies: Earth,
Sun, black hole. All other interactions except gravity are disregarded. For the
outside motion there exists a critical value of coordinate velocity : particles with are accelerated by the
field, like Newtonian apples, particles with are
decelerated like photons. Particles moving inside a body with constant density
have no critical velocity; they are always accelerated. We consider also the
motion of a ball inside a tower, when it is thrown from the top (bottom) of the
tower and after classically bouncing at the bottom (top) comes back to the
original point. The total time of flight is the same in these two cases if the
initial proper velocity is equal to .Comment: 13 page
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