Integral Calculation for Yukawa Potential Differential Cross Section

Click For Summary
SUMMARY

The discussion focuses on the calculation of the differential cross section for Yukawa potential, specifically addressing the conditions under which the term | e(iq - 1/a) | must be less than 1 for the value at r=∞ to vanish. Participants clarify that for q and a being real numbers, the inequality | e(1/a) | > 1 implies that a must be greater than 0. The conversation highlights the importance of understanding the behavior of the exponential term in relation to the Yukawa potential's parameters.

PREREQUISITES
  • Understanding of Yukawa potential in quantum mechanics
  • Familiarity with differential cross section calculations
  • Knowledge of complex exponentials and their properties
  • Basic grasp of limits and behavior of functions as r approaches infinity
NEXT STEPS
  • Study the derivation of Yukawa potential and its applications in particle physics
  • Learn about differential cross section calculations in quantum scattering theory
  • Explore the properties of complex numbers and their implications in physical equations
  • Investigate the significance of boundary conditions in quantum mechanics
USEFUL FOR

Students and researchers in quantum mechanics, particularly those focusing on scattering theory and potential models, will benefit from this discussion.

BREAD
Messages
50
Reaction score
0

Homework Statement


upload_2017-12-20_21-19-23.png


Homework Equations


This is a calculation about differential cross section of Yukawa potential.

The Attempt at a Solution


I can't understand how that highlighted part can be -1 ,
we don't know if the parenthesis term (iq-1/a) is negative or positive tho.
 

Attachments

  • upload_2017-12-20_21-19-23.png
    upload_2017-12-20_21-19-23.png
    19.1 KB · Views: 1,288
Physics news on Phys.org
Subtracting the value at r=0 would give you -1. For the value at r=∞ to disappear, we must have | e(iq - 1/a) | < 1. So if q and a are real, that means | e1/a | > 1, so a>0.
 
FactChecker said:
Subtracting the value at r=0 would give you -1. For the value at r=∞ to disappear, we must have | e(iq - 1/a) | < 1.
==========================================
I don't know why | iq - 1/a | should be smaller than 1 ?
 
BREAD said:
==========================================
I don't know why | iq - 1/a | should be smaller than 1 ?
Sorry. You may have looked at my post as I was correcting it. | e(iq-1/a)r | = | (e(iq-1/a))r | = | (e(iq-1/a)) |r = | (e(-1/a)) |r= 1/| (e(1/a)) |r
 
FactChecker said:
Sorry. You may have looked at my post as I was correcting it. | e(iq-1/a)r | = | (e(iq-1/a))r | = | (e(iq-1/a)) |r = | (e(-1/a)) |r= 1/| (e(1/a)) |r

===================

I appreciate for your quick reply
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

Similar threads

Replies
1
Views
729
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 2 ·
Replies
2
Views
1K
Replies
1
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 6 ·
Replies
6
Views
4K
Replies
1
Views
818
Replies
2
Views
4K
  • · Replies 2 ·
Replies
2
Views
4K