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Thread: Susy

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    Susy

    In SUSY do the super symmetric particles have to be particles, or could they be photons.
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    Quote Originally Posted by Copernicus View Post
    In SUSY do the super symmetric particles have to be particles, or could they be photons.
    Photons are particles, and would have their own superpartner counterparts.

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    Quote Originally Posted by Copernicus View Post
    In SUSY do the super symmetric particles have to be particles, or could they be photons.
    In addition to cjameshuff's points the whole point of SUSY is that bosons have fermionic super-partners and vice versa. So it would invalidate the solution to the hierarchy problem (the required cancellations would not happen), make it impossible for SUSY to contribute to dark matter (which needs to be high mass particles) and seriously hurt the unification fix (because two of the fixes occur in a domain where there are no photons). Essentially all of the major motivations for exploring SUSY would be gone.

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    Quote Originally Posted by Shaula View Post
    In addition to cjameshuff's points the whole point of SUSY is that bosons have fermionic super-partners and vice versa. So it would invalidate the solution to the hierarchy problem (the required cancellations would not happen), make it impossible for SUSY to contribute to dark matter (which needs to be high mass particles) and seriously hurt the unification fix (because two of the fixes occur in a domain where there are no photons). Essentially all of the major motivations for exploring SUSY would be gone.
    I just want to be clear I understand. The fermions would have super partner bosons.
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    Shaula, I think you are saying that SUSY can't handle dark matter. What would happen if there were two superpartner bosons to each fermion, one corresponding to ordinary matter and one corresponding to dark matter.
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    Quote Originally Posted by Copernicus View Post
    Shaula, I think you are saying that SUSY can't handle dark matter.
    It wouldn't be able to if superpartners were photons. They aren't.


    Quote Originally Posted by Copernicus View Post
    What would happen if there were two superpartner bosons to each fermion, one corresponding to ordinary matter and one corresponding to dark matter.
    Ordinary matter is composed of fermions, not superpartner bosons, so that's pretty much a nonsensical question.

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    I feel like you are twisting what I am asking. Would the super partner of a fermion be a boson? Yes or no?
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    would a boson have a fermion super partner?
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    Quote Originally Posted by Copernicus View Post
    I just want to be clear I understand. The fermions would have super partner bosons.
    Yes. For example squarks are all bosons. Selectrons, sneutrinos etc etc.

    Shaula, I think you are saying that SUSY can't handle dark matter.
    No, I'm saying it can at the moment (because super-partners are thought to be very massive). It can't if you make everything photons (because photons are not massive).

    would a boson have a fermion super partner?
    Yes. Photinos, gluinos - all fermions.

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    Quote Originally Posted by Shaula View Post
    Yes. For example squarks are all bosons. Selectrons, sneutrinos etc etc.


    No, I'm saying it can at the moment (because super-partners are thought to be very massive). It can't if you make everything photons (because photons are not massive).


    Yes. Photinos, gluinos - all fermions.
    Thanks, Bosons work for me. I like that idea even better. Now is there any evidence that bosons could be bound in a orbital like structure like electrons?
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    Quote Originally Posted by Copernicus View Post
    I feel like you are twisting what I am asking. Would the super partner of a fermion be a boson? Yes or no?
    You asked about "two superpartner bosons to each fermion, one corresponding to ordinary matter and one corresponding to dark matter".

    Yes, a superpartner to a fermion would be a boson.
    Some forms of SUSY do allow for multiple superpartners.
    Yes, some boson superpartners to ordinary matter fermions might correspond to dark matter.
    The fermions are what comprises normal matter. Asking if boson superpartners to ordinary matter fermions can correspond to ordinary matter doesn't make sense. The question itself is internally inconsistent.

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    Quote Originally Posted by Copernicus View Post
    Thanks, Bosons work for me. I like that idea even better. Now is there any evidence that bosons could be bound in a orbital like structure like electrons?
    If you mean the hierarchy of electron shells, that is a result of the Pauli exclusion principle which applies to fermions only. Bosons can share the same quantum state and would not stack up into shells.

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    Quote Originally Posted by cjameshuff View Post
    If you mean the hierarchy of electron shells, that is a result of the Pauli exclusion principle which applies to fermions only. Bosons can share the same quantum state and would not stack up into shells.
    That is a bummer. I was looking for something that could occupy the same quantum state. But would also have something like electron shells.
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    Quote Originally Posted by cjameshuff View Post
    If you mean the hierarchy of electron shells, that is a result of the Pauli exclusion principle which applies to fermions only. Bosons can share the same quantum state and would not stack up into shells.
    You are saying bosons can't be in orbitals. I see some places discuss bosons as being in orbitals. But they could have many bosons in one orbital. Is this totally wrong or partially wrong.
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    Quote Originally Posted by Copernicus View Post
    You are saying bosons can't be in orbitals. I see some places discuss bosons as being in orbitals. But they could have many bosons in one orbital. Is this totally wrong or partially wrong.
    That is almost correct, Copernicus. cjameshuff did not say "bosons can't be in orbitals". The key word is stack. Bound fermions and bosons will be in shells (orbitals). Fermions stack up into shells because they cannot have the same state and one of those states is energy, i.e. which orbital they occupy. Bosons cannot stack up into shells because they can share the same energy state. Bosons end up in a single shell, not in a stack of shells.

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    do Bosons not have different energy levels where they would go into different energy states?
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    Quote Originally Posted by Copernicus View Post
    do Bosons not have different energy levels where they would go into different energy states?
    Yes, but the point is that orbitals are stable due to exclusion rules. Fermionic orbitals have a maximum possible population per orbital (since each unique state can have one and only one occupant) whereas bosonic orbitals don't (since each unique state can have many occupants). So unless there is some forbidden transition or other mechanism to stop the bosons giving up energy they can all drop to the lowest energy state. That can't happen with fermions because once the lowest state is full that transition becomes forbidden.

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    Quote Originally Posted by Shaula View Post
    Yes, but the point is that orbitals are stable due to exclusion rules. Fermionic orbitals have a maximum possible population per orbital (since each unique state can have one and only one occupant) whereas bosonic orbitals don't (since each unique state can have many occupants). So unless there is some forbidden transition or other mechanism to stop the bosons giving up energy they can all drop to the lowest energy state. That can't happen with fermions because once the lowest state is full that transition becomes forbidden.
    Are you saying the Bosons can be in higher orbitals, but they will quickly give up their energy and drop to the lowest orbital.
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    Quote Originally Posted by Copernicus View Post
    Are you saying the Bosons can be in higher orbitals, but they will quickly give up their energy and drop to the lowest orbital.
    If you can trap bosons in a system that has orbitals (basically just a potential well of an appropriate size) and there is a mechanism for them to lose energy then yes, there is nothing stopping them from dropping into lower levels (unlike fermions where exclusion principles apply). Although it is probably better to just call them energy levels rather than orbitals as they don't have the structure of orbitals - they are just basically allowed energy states of a confined quantum harmonic oscillator.

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    Thanks all for your help. It was very interesting.
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    Quote Originally Posted by Shaula View Post
    If you can trap bosons in a system that has orbitals (basically just a potential well of an appropriate size) and there is a mechanism for them to lose energy then yes, there is nothing stopping them from dropping into lower levels (unlike fermions where exclusion principles apply). Although it is probably better to just call them energy levels rather than orbitals as they don't have the structure of orbitals - they are just basically allowed energy states of a confined quantum harmonic oscillator.
    Shaula, Are you saying that the bosons oscillate between these energy states?
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    Quote Originally Posted by Copernicus View Post
    Shaula, Are you saying that the bosons oscillate between these energy states?
    No. I was referring to the simplest model for calculating energy levels of a system like this. See: https://en.wikipedia.org/wiki/Quantu...gy_eigenstates

    I was simply trying to highlight that orbitals are a specific example of a more general set of solutions and that perhaps a more generic term was more fitting.

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    Quote Originally Posted by Shaula View Post
    No. I was referring to the simplest model for calculating energy levels of a system like this. See: https://en.wikipedia.org/wiki/Quantu...gy_eigenstates

    I was simply trying to highlight that orbitals are a specific example of a more general set of solutions and that perhaps a more generic term was more fitting.
    Thanks Shaula.
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    Are there undetected particles from Tau decay?
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    Quote Originally Posted by Copernicus View Post
    Are there undetected particles from Tau decay?
    Well, we haven't detected any.

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    Quote Originally Posted by cjameshuff View Post
    Well, we haven't detected any.
    This article from today says there is an undetectable neutrino given off. https://phys.org/news/2020-08-heavy-...u-leptons.html

    Searching for Heavy Higgs bosons decaying into two tau leptons with the ATLAS detector
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    Quote Originally Posted by Copernicus View Post
    This article from today says there is an undetectable neutrino given off. https://phys.org/news/2020-08-heavy-...u-leptons.html

    Searching for Heavy Higgs bosons decaying into two tau leptons with the ATLAS detector
    It says “invisible neutrinos” not “undetectable neutrinos.” That’s a press release. More properly it should be something like “hard to directly detect conventional neutrinos.” The neutrinos can be indirectly detected by their missing mass. Direct detection typically takes a lot of neutrinos and big fancy detectors. If there were WIMPs the amount of missing mass would make that clear.

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    https://physics.aps.org/articles/v13/s115. I thought this article was interesting and I really like the idea of dark bosons. The title is hints of dark bosons.
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