Particle physics - invariant mass question

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SUMMARY

The discussion centers on calculating the invariant mass of electron-proton (ep) collisions at HERA, where 30 GeV electrons collide with 820 GeV protons. The correct invariant mass is determined to be 314 GeV. The participants clarify the use of the equation M^2 = (E1 + E2)^2 - (p1 + p2)^2, emphasizing the importance of considering the direction of momentum in the calculations. The solution involves applying the energy-momentum relation E^2 = p^2 + m^2 to find the correct momentum values.

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  • Understanding of particle physics concepts, specifically invariant mass.
  • Familiarity with energy-momentum relations in special relativity.
  • Basic knowledge of collision dynamics in high-energy physics.
  • Proficiency in using equations for calculating mass and momentum.
NEXT STEPS
  • Study the derivation and applications of the invariant mass formula in particle collisions.
  • Learn about energy-momentum conservation in high-energy physics experiments.
  • Explore the role of momentum direction in collision calculations.
  • Investigate the significance of HERA and its contributions to particle physics research.
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Students and researchers in particle physics, particularly those focusing on high-energy collisions and invariant mass calculations.

tigger88
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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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Hint: Consider direction of their momentum.
 
Wow. That was really stupid of me! Thanks for the hint! Got it now :)
 

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