Particle physics - invariant mass question

In summary, the problem involves calculating the invariant mass of ep collisions at HERA, where 30 GeV electrons collide with 820 GeV protons. The equation used is M^2 = (E1 + E2)^2 - (p1 + p2)^2, and the known masses are e=0.0005GeV and p=0.938GeV. Taking into account the direction of momentum, the numerical answer is 314GeV.
  • #1
tigger88
21
0

Homework Statement



At HERA 30 GeV electrons collided head on with 820 GeV protons. Calculate the invariant mass of ep collisions.
(masses: e=0.0005GeV, p=0.938GeV)

Homework Equations



M^2 = (E1 + E2)^2 - (p1 + p2)^2 ?

The Attempt at a Solution



I know the numerical answer to this question is 314GeV, but so far I haven't been able to get it. I've tried plugging in the known values to the above equation, using E^2 = p^2 + m^2 to find momentum, but obviously didn't get the right answer.

What should I be doing?

Thanks!
 
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  • #2
Hint: Consider direction of their momentum.
 
  • #3
Wow. That was really stupid of me! Thanks for the hint! Got it now :)
 

1. What is the concept of invariant mass in particle physics?

Invariant mass is a physical property of a particle that remains the same regardless of the reference frame in which it is observed. It is a fundamental concept in particle physics, as it allows for the precise calculation of a particle's energy and momentum.

2. How is invariant mass calculated?

Invariant mass is calculated using the equation E² = (pc)² + (mc²)², where E is the energy of the particle, p is its momentum, and m is its rest mass. This equation is derived from Einstein's famous equation, E = mc², and is used to determine the mass of a particle even when it is moving at high speeds.

3. Why is invariant mass important in particle physics?

Invariant mass is important in particle physics because it is a fundamental property of particles that remains unchanged in all reference frames. This allows for the accurate measurement and comparison of particles, even when they are moving at high speeds or colliding with other particles.

4. How is invariant mass related to the Higgs boson?

The Higgs boson is a particle that is responsible for giving mass to other particles. Its discovery in 2012 confirmed the existence of the Higgs field, which gives particles their mass through interactions. The Higgs boson itself has a specific invariant mass, which was measured by the Large Hadron Collider in order to confirm its existence.

5. Can invariant mass be negative?

No, invariant mass cannot be negative. It is a physical property that must have a positive value, as it represents the mass of a particle. However, it is possible for the invariant mass of a system of particles to be zero, which is the case for photons, as they have no rest mass.

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