The Majorana mass term is expressed from a single Weyl spinor. But I am a little confused by the expression. For example, see Eq. (2) in http://arxiv.org/pdf/hep-ph/0410370v2.pdf(adsbygoogle = window.adsbygoogle || []).push({});

[itex]\mathcal{L}=\frac{1}{2}m(\chi^T\epsilon \chi+h.c.)[/itex]

Here [itex]\chi[/itex] is the Weyl spinor and [itex]\epsilon = i\sigma^2 [/itex] is the antisymmetric tensor.

But when I do a simple calculation:

[itex]\chi^T\epsilon \chi =(\chi^T\epsilon \chi)^T = \chi^T(-\epsilon) \chi [/itex]

Here I used [itex]\epsilon^T = -\epsilon[/itex]

therefore [itex]\chi^T\epsilon \chi =0 [/itex]

So can anyone tell me what is wrong here? What is missing here? Thanks a lot

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# Question about the Majorana mass term

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