# Recent content by Imanbk

1. ### Machine accuracy vs. smallest representable number vs. smallest normalized number

Homework Statement "Explain the difference between the machine accuracy, the smallest representable number, and the smallest normalized number in a floating point system". Homework Equations There is the bit-representation of floating numbers: (-1)^S * M * b^(E-e), using the fact that we can...
2. ### P+p -> p + (anti)p

Thanks a bunch everyone! This discussion was really useful for me, and I hope a few others. Vanadium: Thanks for confirming the invariant momentum approach.. I was getting worried! And I finally found the proper way of calculating the velocity between the two frames :) So things like KE...
3. ### P+p -> p + (anti)p

Hi PAllen, I'm guessing there's a square root around the denominator? Do you get the velocity from relativisitc momentum? Why is m(\gamma -1) needed? Are you using KE = E-mc^2 ? I'm studying for a test and it'd be nice to clarify this problem now :) Thanks for the input!
4. ### P+p -> p + (anti)p

Bill_K: Can you please let me know how you got to this answer? Thanks..
5. ### P+p -> p + (anti)p

Vanadium: Thank you... I was actually starting to think the same. There is one little problem: when I calculate the boost and calculate the momentum in the proton rest frame using the boost I get something different, I get 15.869 GeV. Here are my equations: y is the boost, p'_z =...
6. ### P+p -> p + (anti)p

Correction: Sorry, I meant (P^\mu)^2 is an invariant..
7. ### P+p -> p + (anti)p

PAllen: Thanks for the reminder! So I can find the boost using the ratio of energy and z-momentum, and supposing y is my boost, the energy in the lab frame would be: E' = E cosh(y) + p^z sinh y Is this correct? Nugatory, Bill_K, PAllen: Thanks for all of your input. I've thought of...
8. ### P+p -> p + (anti)p

Hi Nugatory! Thanks for suggesting this reaction! It seems to conserve what it has to conserve (charge, baryon number). When I use the same calculation steps as I did originally, and assume the minimum required momentum for the incoming particle is when all outgoing particles have zero...
9. ### P+p -> p + (anti)p

p+p --> p + (anti)p Hi everyone, I'm looking at the following problem from C. Bertulani's Ch.1, Problem 6. The problem statement is: "Using relativistic expressions for momentum and energy conservation, show that a proton must have energy greater than 5.6 GeV to produce a proton-antiproton...
10. ### Can an even number of Fermions be a Bosonic system?

Hi everyone, I've just done a problem where we are dealing with two protons with the same spin directions and the system is treated as a fermionic system. I always had the notion that two (or an even number of) fermions, for opposite spin perhaps, act as bosons. Is this true? If so, when...
11. ### Why does vacuum have energy?

Thanks everyone for your helpful replies! I think my thinking of the "vacuum" was naive as you have pointed out.. I was thinking of a box of "nothing" having some choosen base energy which we call the zero energy, and with this idea I wasn't sure why taking a larger box would have an even...
12. ### Why does vacuum have energy?

Hello Everyone, I've been asked to work out a problem about vacuum energy <0|H|0> where H is the energy density of harmonic oscillator. When I integrate this expectation value over space of finite dimensions L, I get that the expectation value for the vacuum energy scales as L^3 . Does...
13. ### Why does Klein-Gordon's equation not obey quantum mechanics?

Bill_K, thank you very much for your explanation!
14. ### Why does Klein-Gordon's equation not obey quantum mechanics?

Thank you very much for the wake-up call on the 4-vector notation! Regarding the time-dependence, I understand the point made now, thank you. However, how would having an equation of motion which is first order in time solve this problem of the time dependence in the probability? Or, why does a...
15. ### Why does Klein-Gordon's equation not obey quantum mechanics?

Hello Everyone, I was reading in Srednicki's QFT book, Chapter 1 and he was explaining why the Klein-Gordon equation doesn't obey quantum mechanics. He said the fact that the time derivative is second order means it disobey's Shrodinger's equation which is first order in the time derivative...