# Prerequisites for learning MSSM --> proton decay prediction?

1. Jun 9, 2015

### Anchovy

Hi all,

I'm attempting to write something on proton decay (specifically in the $p \rightarrow K^{+} \nu$ channel) and need to understand some theory that predicts it. I'm under the impression that the MSSM is the most straightforward theory. However, I look through introductory texts/documents and I get lost almost immediately in a jungle of symbols and terminology that the author always assumes are understood. I'm wondering what I need to brush up on first before I tackle this stuff, and perhaps if anyone knows of any good resources to get me up and running?

2. Jun 9, 2015

### Orodruin

Staff Emeritus
What is your current level of understanding in theoretical particle physics?

3. Jun 9, 2015

### Staff: Mentor

What do you mean with "write something"? What is your educational background, what is "something" supposed to be?

Edit: Orodruin was faster.

4. Jun 9, 2015

### Anchovy

Well I'm a postgrad student, I've done courses in introductory QFT, QED, standard model etc. but that was a long time ago now, long enough to have forgotten it all. I'm looking through these texts and seeing so many things I'm vaguely familiar with but no longer remember the meaning of. So I'm not a complete beginner but I do need to cover the basics again in a timely manner.

Actually it's gonna go into an early chapter of my PhD thesis. I've been able to ignore the underlying theory up till this point, I don't need to write a huge amount but I need to understand something.

Last edited: Jun 9, 2015
5. Jun 9, 2015

Staff Emeritus
If you can write any theory, why pick MSSM? Why not SU(5)?

6. Jun 10, 2015

### Anchovy

Well maybe SU(5) is the one for me, my intention was to go for the most ubiqiutous one, I was under the impression that that might've been MSSM.

7. Jun 10, 2015

### ChrisVer

Well I don't think MSSM alone predicts proton decay (at least when R-parity is applied)... I think in the MSSM you have to get some GUT no matter what, to get proton decay (like the Supersymmetric SU(5) GUT).

8. Jun 10, 2015

Staff Emeritus
SUSY has B-violating terms, and R-parity blocks it, SU(5) give sproton decay; usually too much.

9. Jun 10, 2015

### ChrisVer

It doesn't necessarily need sproton but also proton decay.
One diagram that can lead to such a decay ($ud \rightarrow \bar{s} \bar{\nu}$ or $p \rightarrow K^+ \bar{\nu}_i$) is given below. Where the internal lines contain Yukawa couplings of the higgsino triplets $\tilde{h}^{(3)}_1,\tilde{h}^{(3)}_2$ to light squarks ($\tilde{u}_{Li}$) and sleptons ($\tilde{e}_{Lj}$) and the GUT partners of the MSSM higgsinos ($\tilde{\chi}_k$).
Of course one can find comments about such processes. Figure was taken from M.Drees's "Theory and Phenomenology of sParticles" pg.301 I think, fig.12.8.
OPer:You can have a look in that book if you like.

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