It is known that when the speed of an elementary particle approaches the speed of light, its acceleration by an electric or magnetic field decreases. According to STR, this is due to the nonlinear increase in momentum (mass). Have direct measurements of the momentum been carried out through the pressure exerted by the beam of relativistic particles on the target at different speeds?
The decrease in acceleration may be due not to "relativistic corrections", but to an increase in the friction force against the "physical vacuum".
It´s happens because of change in time, see the episody of relativity in Mechanical Universe series for a better understanding.
Dear Preston,
As far as I know, all methods used to measure the energy are indirect. The direct method for particle with mass m flying at a speed of V requires the direct measurements of V and m (or its momentum) without using theoretical assumptions consistent with STR.
Dear Alexander,
You’re wrong. All methods that are being currently used at the LHC or Tevatron are directly measuring the energy of the colliding particles. This can be done by using calorimeters made of specific materials, such that they measure the energy depositions in them. The energy of the protons accelerating, and thus their momentum, is Measured as the electric and magnetic fields accelerating the particles are known. Thus, you only need to calculate
K=1/2 (E^2+B^2) for Knowing the total energy and momentum.
Dear Gustavo,
With the help of calorimeters, light flashes or emerging charges from a shower of secondary particles are registered. Then the statistical analysis of the data obtained and calculations according to certain, non-trivial theory are performed. The method for calculating energy of the primary particle is thus not direct.
Dear Alexander,
If you mean by primary particles for example protons, then their energy is well known. Now, if primary particles are for example vector bosons or heavy particles, then a statistical Analysis has to be carried out. But this is due to its short lifetime and lack of performance efficiency from the detectors.
Dear Gustavo,
Let's consider a "relativistic" beam of N protons. On the basis of what are the proton energies in it well known?
Dear Alrik,
Thank you for description of many possible methods for measuring the energy which I can, in your opinion, to do. The most direct method for measuring kinetic energy of the "relativistic" beam from your text is the kinetical one- by colliding of two opposite beams with the target. Could you give any reference at the relevant experiment?
The energy of a "relativistic" particle may be composed by not only kinetical part but and potential part also ("rest energy" in STR). The second one may play increasing role in interactions at the speeds closed to c. Thus, to reliable obtain the momentum only kinetical experiments are appropriate.
Regarding independence and agreement of the different experiments: don't forget that all of them were made in the main stream of STR and used calculation methods may have been adjusted to satisfy well-kown relativistic formulas for energy and momentum.
Dear Alrik,
If you try to calculate kinetic energy of a car using STR formula, you obtain wrong result. The car is the composition of many elementary particles...
P.S. Don't delete messages, please. It is not a constructive discussion method.
Dear Alrik,
A relativistic car is fiction. My remark above is about real, low speed car.
The content of the textbook through your link confirms that all calculations in the experiments on the topic are carried out in the STR stream. However, it does not mean that the available experimental data in physics of high energies and elementary particles cannot be described by another, better theory. I do not refute STR, but ask simple question concerning its basis.
So far, no one has given a reference to a direct experiment on measuring the momentum of a high-speed ("relativistic") particle.
Checking the "relativistic kinematics" by detecting optical radiation arising from the annihilation of flying positrons is not a direct and reliable method. Kinematics is the mechanics section. To reliable check it in any experiment, one need to measure the mechanical parameters (speed, acceleration, force) directly.
P.S. You can keep your pedagogical abilities to your students. If you have nothing more to say on the merits of the question, you should not waste time promoting STR here. Thanks.
Dear Alrik,
Einstein's formula for kinetic energy corresponds to the classical formula at low speeds only approximately. Mass–energy equivalence principle is not physical in itself. "In physics, energy is the quantitative property that must be transferred to an object in order to perform work on, or to heat, the object." Just because an object has mass does not mean that it is able to do work or heat other objects. To do this, it must either be in motion (kinetic energy) or have a certain structure, the change of which can lead to do work or heat (potential energy).
I would not want to discuss artifices of STR and calculations based on them here.
Thank you for participation in the discussion. Goodbye.
- Badges
- Science topic
- Similar topics
- Automotive Engineering
- Machines