How to; polarized reaction ee--->WW

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SUMMARY

The discussion focuses on computing the polarized cross-section for the reaction $$ e^{-}e^{+} \rightarrow W^{-}W^{+} $$, emphasizing the chiral nature of the process which restricts input helicities to two while allowing nine output combinations of W-boson polarizations. The user seeks clarification on the relationship between helicity and spinor representations, specifically how left-handed positrons correspond to right-handed spinors and vice versa. Additionally, the user inquires about graphing the energy dependence of the reaction based on the matrix element M, referencing problems from Peskin & Schroeder. The user successfully completed the computation and offers a PDF of their findings.

PREREQUISITES
  • Understanding of particle physics, particularly chiral interactions.
  • Familiarity with helicity and spinor notation in quantum field theory.
  • Knowledge of matrix elements and their role in calculating cross-sections.
  • Experience with graphing functions in the context of particle interactions.
NEXT STEPS
  • Study the derivation of the matrix element M for polarized reactions in quantum field theory.
  • Learn about the orthogonality of polarization vectors for W-bosons.
  • Explore graphing techniques for energy dependence in particle physics, particularly using $$ \frac{d}{d\cos\theta} $$ vs. $$ \cos\theta $$.
  • Review problems 21.1, 21.10, and 5.1 in Peskin & Schroeder for deeper insights into similar calculations.
USEFUL FOR

Particle physicists, graduate students in theoretical physics, and researchers working on electroweak interactions and cross-section calculations.

moss
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I want to compute the polarized cross-section of $$ {e^{-}e^{+}\rightarrow W^{-}W^{+}} $$
but this reaction is chiral and only 2 input helicities are allowed while 9 out put combinations of W-boson helicities/polarization are possible. W(+-0) & W(+-0) are the possible polarization of W-bosons.

The Qs. I am given is that compute the above reaction in high-energy limit so I guess I have to compute the matrix-M but does it also mean to compute the cross-section??

Further;

1: I am having difficulty to understand that how a left-handed positron has a right-handed spinor
and a right handed electron has a left-handed spinor, they are mostly denoted as v(p) & u(p').

2: From the matrix element M how can I draw a graph between $$ {\frac{d}{dcos\theta}} $$ and $$ {cos\theta} $$. OR how can I show the energy dependence of this reaction in graph?

this is the almost the same problem as peskin & schroeder 21.1 and the graphs are 21.10 and 5.1 of the same book.

any hint is much appreciated.
 
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Okay, I got my Qs-1, actually I wrote wrong, only the spinor of anti-particle has opposite handedness and for the particle its the same handedness.
Some of the matrix-M are zero because of the orthogonality of the polarization vectors of the W-bosons.

Qs-2 still stand as how to draw the graph.
Any help??
 
Okay, I have completed the complete polarized reaction and cross section of e^{-}e^{+}\rightarrow W^{-}W^{+}.
Anybody interested in this can download the pdf. or email me and I will mail you the pdf.
 

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