How Does Detector Resolution Affect the True Width of the J/psi Particle?

[malawi_glenn]

Hi!

I have been reading a bit about the J/psi resonance, and I was wondering about this thing:

Its true width is relative very small, and all the diagrams I've seen are experimental and they state that the widht in the graph is not the true, but arises due to decetor resolution.

I was wondering if the cross section at the resonance energy (3097MeV CM-frame in e+e- collision) that is given in my experimental figures (140nb) is the same as the real cross section? The graphs I have states that the integrated cross section is 800nb MeV, but this has nothing do to with the issue I suppose? I am curious how to determine the true width of the J/Psi resonance.

If the real and experimental cross section is the same ,then one can easy determine the true widht by using Breit-Wigner formula, i can look up the branching ratios at particle data group.

What I am asking is: Does the dector only make the peak broader, or is it also affecting the hight in a non-neglectable manner?

EDIT: I found this paper: http://particle.korea.ac.kr/class/2005/phys602/phys602-04.pdf
But I don't think I understand how the detector changes the peak the way it does, the width I understand, but not the height:/

 

[pam]

There is an experimental uncertainty in the beam energy.
This means that when the central beam energy is at the resonancem peak,
the measured peak cross-section is a weighted average of the energy spread of the beam.

 

[sir-pinski]

Hello!

The J/psi particle, also known as the J/psi meson, is a subatomic particle that was first discovered in 1974. Its true width is indeed very small, on the order of 1 MeV. However, as you mentioned, the width that is typically shown in experimental diagrams is not the true width, but rather the experimental resolution. This is because detectors have a finite resolution and cannot measure the exact width of a particle. Therefore, the observed width is a combination of the true width and the detector resolution.

The cross section at the resonance energy, 3097 MeV, is related to the true width of the J/psi particle through the Breit-Wigner formula. However, the integrated cross section of 800nb MeV that you mentioned is not directly related to the true width. It is a measure of the total number of J/psi particles produced in a given collision energy and is affected by factors such as the production mechanism and branching ratios.

In terms of determining the true width, the detector does not affect the height of the peak. It only affects the width. The height of the peak is determined by the production rate of the J/psi particle and is not influenced by the detector.

I hope this helps clarify your questions about the true width of the J/psi particle. The paper you found may provide more detailed information on how the detector affects the peak shape, but as a general overview, the detector mainly affects the width, not the height.