B meson from proton antiproton collision

In summary: You calculate the total momentum of the proton and antiproton and use the law of conservation of momentum.
  • #1
Masafi
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The B+ particle and B- particle are produced by higher energy collisions between protion and anti protons. The B meson has a mass of 5.28 GeV/c^2. The proton has mass 938 MeV/c^2.

Calculate the min KE of the proton neccesary for a B+ B- pair to be produced from a proton anti-proton head on collision.


Not sure of the method to solve this. The answer is 4.3GeV
 
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  • #2
The total 4-momentum in the initial state has zero 3-momentum (head on collision) and twice the energy of one proton. The total 4-momentum in the final state has zero 3-momentum (threshold production) and twice the mass of the B. Let's write down the equality of the squared total 4-momenta

[tex]4\times E^2=4\times M^2[/tex]

[tex]E - m=K=M-m[/tex]

[tex]K=5.28-0.938=4.342[/tex]
 
  • #3
humanino said:
The total 4-momentum in the initial state has zero 3-momentum (head on collision) and twice the energy of one proton. The total 4-momentum in the final state has zero 3-momentum (threshold production) and twice the mass of the B. Let's write down the equality of the squared total 4-momenta

[tex]4\times E^2=4\times M^2[/tex]

[tex]E - m=K=M-m[/tex]

[tex]K=5.28-0.938=4.342[/tex]

I haven't studied this method. All I have done is conservation of linear momentum, how to work out KE, and switching from eV/c^2 to kg etc.

Can this be solved using that knowledge?
 
  • #4
The minimum energy to produce the B+ and B- is when they are created at rest, so the total energy is the sum of their rest energies, [itex]2m_Bc^2[/itex]. Since both particles are at rest, their total momentum is zero.

Because energy and momentum are conserved, you know the total energy and momentum of the proton and antiproton. From this information, you should be able to calculate the energy of the proton and therefore its kinetic energy.
 
  • #5
vela said:
The minimum energy to produce the B+ and B- is when they are created at rest, so the total energy is the sum of their rest energies, [itex]2m_Bc^2[/itex]. Since both particles are at rest, their total momentum is zero.

Because energy and momentum are conserved, you know the total energy and momentum of the proton and antiproton. From this information, you should be able to calculate the energy of the proton and therefore its kinetic energy.

Rest Energy of B mesons produced = 5.28GeV * 2c^2 = 10.56* c^2 GeV

Rest E of proton and anti proton = 1.876 * c^2 GeV

So KE = Rest E of B mesons - Rest E of protons
= 8.684 * c^2 GeV
= 7.82 x 10^17 GeV??

The answer is meant to be 4.3GeV
 
  • #6
An electron-volt is a unit of energy, so the rest energy of a B meson is 5.28 GeV, not 5.28 GeV*c^2. The mass of the B meson could be written as 5.28 GeV/c^2, but you don't generally plug a value in for c. You just leave it as c.

Also, remember that the question asked you for the kinetic energy of the proton, not the proton-antiproton pair.
 
  • #7
Masafi said:
[...] how to work out KE [...]

Can this be solved using that knowledge?
Yes. How do you work out KE ?
 

FAQ: B meson from proton antiproton collision

1. What is a B meson?

A B meson is a type of subatomic particle that is composed of a quark and an antiquark. Specifically, it is made up of a bottom quark and an up or down antiquark.

2. How is a B meson produced in a proton antiproton collision?

When a proton and antiproton collide, their quarks can interact and produce a variety of particles, including the B meson. This process involves the annihilation of the proton and antiproton, which releases a large amount of energy that can be used to create new particles.

3. What are the properties of a B meson?

B mesons have a mass of approximately 5.28 GeV/c^2 and a lifetime of around 1.5 picoseconds. They also have a net charge of 0 and a spin of 0.

4. What can studying B mesons tell us about the nature of matter?

The study of B mesons can provide insights into the fundamental properties of matter, such as the behavior of quarks and the forces that govern their interactions. It can also help us understand the origins of the universe and the processes involved in the formation of matter.

5. How are B mesons used in particle physics experiments?

B mesons are used in a variety of particle physics experiments, including those studying CP violation and searching for new physics beyond the Standard Model. They can also be used to test theories and models of particle interactions and to probe the structure of matter at a very small scale.

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