# B Supersymmetry / antimatter

1. Dec 4, 2016

### hsdrop

ok guys this should be a quick one... I hope lol
In supersymmetry could the other have of the particles be antimatter ?? its looking like the same thing to me.... but I could be very wrong. But if I am, why would I be wrong ??

thank you to anyone that takes the time to replay

File size:
38.5 KB
Views:
57
2. Dec 4, 2016

### secur

No, the supersymmetric partner (SUSY particle) of a particle can't be its antiparticle. For one thing an antiparticle has the same mass, the partner doesn't. The role played by the partner, in enabling renormalization, couldn't be implemented by the antiparticle. Your first diagram, showing particles on the left and SUSY particles on the right, is not showing antiparticles explicitly, because they're assuming that's understood. Someone else could give a more technical explanation, I'm not very familiar with supersymmetry. But I'm quite sure of the answer: No :-)

3. Dec 4, 2016

### Staff: Mentor

• We found all the antimatter particles. We found none of the supersymmetric particles which have different properties.
• Antimatter particles have the same spin as matter particles, supersymmetric partners do not. Antiparticles have the same masses as particles, supersymmetric partners do not.
• Particles which don't have antimatter equivalents still have supersymmetric partners (if there is supersymmetry).
• The Higgs sector looks different with supersymmetry.
• Thinking that you can contribute an original idea to physics like that is absurd.

4. Dec 4, 2016

### hsdrop

sorry I was not trying to go for a contribute, i'm not even sure if I would know how to
I was just finding out what the differences between the straight and squiggly lines
and try to learn a little along the way

5. Dec 13, 2016

### David Neves

The problem is the popular media. A popular science article might show the diagram of the particles and their antiparticles, and another popular science article might show a diagram of the particles and their super partners, without any explanation as to what these particles are, what their properties are, how we know they exist, or think they exist. Then a member of the public, without a scientific background, sees the diagrams, and thinks "Hey! What if they are the same?" The real fault lies with bad science journalism.

6. Dec 14, 2016

### hsdrop

thank you for answering the post. My self, I love almost all forms of scince and try to learn as much as my little brian can understand every night before bed. I am so glad that we as a people/civilization have a way of communicating with with each other and can weed out the good info from the bad. I come to this forum and ask the questions that I do cause I seek the truth and not rely on bad science journalism

7. Dec 14, 2016

### newjerseyrunner

Learning how to separate pop-science from real science is one of the more difficult things. Even harder is learning to separate simplifications used as learning tools from the more complex stuff.

If John Smith writes an article on hawking radiation and cites Stephen Hawking, it's probably crap.
If Hawking himself writes an article in a pop science magazine, it's accurate, but details like what virtual particles are have been glossed over or given a laymen explanation.
If Hawking submits a paper to a peer reviewed journal, it's good, but probably a little beyond most readers.

Antimatter came out of the formulation of QED. Dirac realized that there was no reason that an electron wave would only work if it was negatively changed, it was equally valid with the opposite.

Supersymmetry is attempting to solve a problem in the math of QM. The math of QM requires you to do the calculations of the fermions, then add the calculation of the bosons. That's weird. In most addition X + Y is the same as Y + X. That's not true in QM. Supersymmetry adds more terms to the equation to make them interchangeable.

Last edited: Dec 14, 2016
8. Dec 14, 2016

### Staff: Mentor

It was not only possible, it was a direct consequence of combining special relativity and quantum mechanics.
What?

Without supersymmetry, the corrections to the Higgs mass diverge (more precisely: go up to the UV cutoff, like the Planck scale). There is no Y to add to an X, the X itself is the problem.
With supersymmetry, bosons cancel the contributions from fermions approximately, so the divergence gets much weaker (only with the logarithm of the mass). Here (!) you have to take care that you sum the contributions in the right way. You cannot calculate either X+Y nor Y+X naively because both terms diverge, only their sum evaluated in the right limit is well-defined and not as large as the Planck scale.

9. Dec 14, 2016

### stoomart

Your posts are my favorite thing about these forums.

10. Dec 15, 2016

### hsdrop

I am so sorry to ask this. Is there a way for you to simplify what you are describing so I can understand it a little better??

also I have somewhat of a good grasp of what antimatter is (because it easer to look up and understand for me at least) I'm just not quite sure how we can make antimatter particles to study them

I want to thank everyone for taking the time to answer my questions and being so very patient with me

Last edited: Dec 15, 2016
11. Dec 15, 2016

### Staff: Mentor

Sorry, that was mainly written for newjerseyrunner. I'll try to explain it in easier terms:

It is one of the theoretical issues of the standard model (which includes antiparticles, but no supersymmetry). Particle masses there depend on the existence of other particles because they interact with those particles. This effect is small for most particles, but it is important for the Higgs boson mass. If you try to calculate it, you get an integral that looks a bit like
$$\int_0^\infty 1 dx$$
Here x is an energy scale of the interaction. "Multiply 1 by infinity": The integral is not well-defined. We know that our theories break down where gravity gets relevant (this happens at the Planck mass mP), so it does not really make sense to include energy scales above the Planck mass:
$$\int_0^{m_P} 1 dx = m_P$$
"Multiply 1 by a large number": That works mathematically, the result is a large number. The Higgs mass mH is the sum of this contribution and a different mass source mb: mH = mP + mb. The value of this different mass source can be anything - it is a free parameter.

The Planck mass is about 10000000000000000000 GeV, the Higgs mass is 125 GeV. The units don't matter here, only the numbers are important. So we get an equation that looks like "add a number like 10000000000000000000 and a completely unrelated number, and the result is 125". That means mb is something like -9999999999999999874 GeV, extremely close to the Planck mass but not exactly identical. Possible? Yes. But it doesn't look likely. The problem is the huge Planck mass which enters the equation.

With supersymmetry, we get additional particles (the superpartners of the known particles). They also influence the particle masses, and it turns out that their effect is exactly the opposite. The integral from above is now zero:
$$\int_0^{m_P} (1-1) dx = 0$$
With this approach, regular particles and their superpartners would have identical masses. In this case we would have found the superpartners already, so this cannot be true. Supersymmetry must be broken (it is not exactly symmetric), and the superpartners have different masses. So we have to modify the integral again, and it now looks a bit like this:
$$\int_1^{m_P} (1-1+\frac{1}{x}) dx = ln(m_P)$$
I cheated a bit here to avoid introducing too many technical details. The main point: Instead of a huge number, with supersymmetry we just get the logarithm of a huge number - which is much more reasonable.

Collide particles at high energies. In the collisions, all types of particles get produced. Usually as pairs of matter plus antimatter particle, which then fly apart.

12. Dec 15, 2016