Notices
Results 1 to 16 of 16

Thread: Large Hadron Collider vs Dark matter

  1. #1 Large Hadron Collider vs Dark matter 
    Forum Bachelors Degree PetTastic's Avatar
    Join Date
    Jul 2010
    Location
    London UK
    Posts
    421
    I was reading this:
    Should we worry about what the LHC is not finding? - physics-math - 25 July 2011 - New Scientist

    The LHC is not finding any signs of supersymmetry particles below 1 TeV.

    Do people think that these particles were not good candidates for dark matter anyway?
    If dark matter particles are much heavier than 1 TeV there will not be many per unit volume and chances of detecting an annihilation event drop away.

    Maybe these particles can not be created by bashing normal matter together?


    I believe in nothing, but trust gravity to hold me down and the electromagnetic force to stop me falling through
    Physics is the search for the best model not the truth, as only mythical beings know that.
    Reply With Quote  
     

  2.  
     

  3. #2  
    Forum Professor arKane's Avatar
    Join Date
    Apr 2009
    Location
    Washington state
    Posts
    1,181
    Quote Originally Posted by PetTastic View Post
    I was reading this:
    Should we worry about what the LHC is not finding? - physics-math - 25 July 2011 - New Scientist

    The LHC is not finding any signs of supersymmetry particles below 1 TeV.

    Do people think that these particles were not good candidates for dark matter anyway?
    If dark matter particles are much heavier than 1 TeV there will not be many per unit volume and chances of detecting an annihilation event drop away.

    Maybe these particles can not be created by bashing normal matter together?
    I have a lot more confidence that they will find the Higgs boson, than they will actually find dark matter. So not finding dark matter won't be much of a surprise and also not much to worry about.


    Reply With Quote  
     

  4. #3  
    Forum Bachelors Degree x(x-y)'s Avatar
    Join Date
    Jul 2010
    Location
    UK
    Posts
    462
    If they don't find dark matter for quite a while then we should actually be happy seeing as we theorise that it is comprised up of WIMPs (Weakly Interacting Massive Particles) and so should pass straight through ordinary matter the vast majority of the time- it should only collide with the nucleus of an ordinary matter atom every once in a while; which is why we have dark matter detection experiments in mines where germanium is cooled to 1/1000 of a degree above absolute zero and so if a dark matter particle would collide with this upon their journey through the Earth they will heat up the whole thing by a tiny amount (but a measurable amount of course).

    As with arKance, I have more confidence of them finding the Higgs Boson at the LHC- and even know as I type data from some of the latest collisions is being analysed as the Higgs may have been found, but it is only of around 3-sigma level certainty as yet. To be honest, though, I hope they don't find the Higgs Boson, I hope it doesn't exist- it would be a lot more exciting for particle physics if this is the case, in my opinion anyway.
    "Nature doesn't care what we call it, she just does it anyway" - R. Feynman
    Reply With Quote  
     

  5. #4  
    Forum Professor arKane's Avatar
    Join Date
    Apr 2009
    Location
    Washington state
    Posts
    1,181
    Quote Originally Posted by x(x-y) View Post
    If they don't find dark matter for quite a while then we should actually be happy seeing as we theorise that it is comprised up of WIMPs (Weakly Interacting Massive Particles) and so should pass straight through ordinary matter the vast majority of the time- it should only collide with the nucleus of an ordinary matter atom every once in a while; which is why we have dark matter detection experiments in mines where germanium is cooled to 1/1000 of a degree above absolute zero and so if a dark matter particle would collide with this upon their journey through the Earth they will heat up the whole thing by a tiny amount (but a measurable amount of course).

    As with arKane, I have more confidence of them finding the Higgs Boson at the LHC- and even know as I type data from some of the latest collisions is being analysed as the Higgs may have been found, but it is only of around 3-sigma level certainty as yet. To be honest, though, I hope they don't find the Higgs Boson, I hope it doesn't exist- it would be a lot more exciting for particle physics if this is the case, in my opinion anyway.
    You have a cool avatar. What do you hope they will find? You have to admit that they've invested a lot of money. While not finding anything might be exciting in a way. The salivating public needs a bone, and before you say it I don't want to hear about micro black holes. I find that harder to believe than dark matter.
    Reply With Quote  
     

  6. #5  
    Moderator Moderator Dishmaster's Avatar
    Join Date
    Apr 2008
    Location
    Heidelberg, Germany
    Posts
    1,624
    I would find it much more exciting, if at some point we realise that there is no such thing as Dark Matter. I am favouring a modified theory of gravity.
    Reply With Quote  
     

  7. #6  
    Forum Professor arKane's Avatar
    Join Date
    Apr 2009
    Location
    Washington state
    Posts
    1,181
    Quote Originally Posted by Dishmaster View Post
    I would find it much more exciting, if at some point we realise that there is no such thing as Dark Matter. I am favouring a modified theory of gravity.
    At least not the dark matter they appear to be looking for. But I would be interested in hearing more about a possible modified theory of gravity. Do you have anything in mind?
    Reply With Quote  
     

  8. #7  
    Moderator Moderator Dishmaster's Avatar
    Join Date
    Apr 2008
    Location
    Heidelberg, Germany
    Posts
    1,624
    Quote Originally Posted by arKane View Post
    Quote Originally Posted by Dishmaster View Post
    I would find it much more exciting, if at some point we realise that there is no such thing as Dark Matter. I am favouring a modified theory of gravity.
    At least not the dark matter they appear to be looking for. But I would be interested in hearing more about a possible modified theory of gravity. Do you have anything in mind?
    The non-relativistic framework is MOND (Modified Newtonian Dynamics). There is a relativistic expansion of this idea. Quite a number of publicatins can be found here:
    arXiv.org Search
    arXiv.org Search

    In particular:
    [astro-ph/0601431] Modified gravity without dark matter
    [astro-ph/0701848] The modified Newtonian dynamics-MOND-and its implications for new physics
    [0806.2585] From dark matter to MOND
    Reply With Quote  
     

  9. #8  
    Forum Professor arKane's Avatar
    Join Date
    Apr 2009
    Location
    Washington state
    Posts
    1,181
    Quote Originally Posted by Dishmaster View Post
    Quote Originally Posted by arKane View Post
    Quote Originally Posted by Dishmaster View Post
    I would find it much more exciting, if at some point we realise that there is no such thing as Dark Matter. I am favouring a modified theory of gravity.
    At least not the dark matter they appear to be looking for. But I would be interested in hearing more about a possible modified theory of gravity. Do you have anything in mind?
    The non-relativistic framework is MOND (Modified Newtonian Dynamics). There is a relativistic expansion of this idea. Quite a number of publicatins can be found here:
    arXiv.org Search
    arXiv.org Search

    In particular:
    [astro-ph/0601431] Modified gravity without dark matter
    [astro-ph/0701848] The modified Newtonian dynamics-MOND-and its implications for new physics
    [0806.2585] From dark matter to MOND
    It seems like this topic is still very much a work in progress. It's very technical but I think I have a jest of it. If you are keeping an eye on developments, please keep us posted.
    Reply With Quote  
     

  10. #9  
    Forum Bachelors Degree x(x-y)'s Avatar
    Join Date
    Jul 2010
    Location
    UK
    Posts
    462
    Quote Originally Posted by arKane View Post
    Quote Originally Posted by x(x-y) View Post
    If they don't find dark matter for quite a while then we should actually be happy seeing as we theorise that it is comprised up of WIMPs (Weakly Interacting Massive Particles) and so should pass straight through ordinary matter the vast majority of the time- it should only collide with the nucleus of an ordinary matter atom every once in a while; which is why we have dark matter detection experiments in mines where germanium is cooled to 1/1000 of a degree above absolute zero and so if a dark matter particle would collide with this upon their journey through the Earth they will heat up the whole thing by a tiny amount (but a measurable amount of course).

    As with arKane, I have more confidence of them finding the Higgs Boson at the LHC- and even know as I type data from some of the latest collisions is being analysed as the Higgs may have been found, but it is only of around 3-sigma level certainty as yet. To be honest, though, I hope they don't find the Higgs Boson, I hope it doesn't exist- it would be a lot more exciting for particle physics if this is the case, in my opinion anyway.
    You have a cool avatar. What do you hope they will find? You have to admit that they've invested a lot of money. While not finding anything might be exciting in a way. The salivating public needs a bone, and before you say it I don't want to hear about micro black holes. I find that harder to believe than dark matter.
    Of course, either way (finding Higgs Boson or not finding Higgs Boson) the future of particle physics is going to be incredibly exciting- a field which I am hoping to go into too! Obviously, I want some revolutionary "things" to be discovered at the LHC- and chances are they will be found- however, the Higgs is not the only particle being searched for, they're also looking for superpartner particles (to help to prove SUSY), evidence for superstring theory, evidence for M-Theory, quantum technicolor force etc. All of these are exciting new possibilities for the LHC, and will revolutionise physics by introducing completely new physics.
    "Nature doesn't care what we call it, she just does it anyway" - R. Feynman
    Reply With Quote  
     

  11. #10  
    Forum Professor arKane's Avatar
    Join Date
    Apr 2009
    Location
    Washington state
    Posts
    1,181
    Quote Originally Posted by x(x-y) View Post
    Of course, either way (finding Higgs Boson or not finding Higgs Boson) the future of particle physics is going to be incredibly exciting- a field which I am hoping to go into too! Obviously, I want some revolutionary "things" to be discovered at the LHC- and chances are they will be found- however, the Higgs is not the only particle being searched for, they're also looking for superpartner particles (to help to prove SUSY), evidence for superstring theory, evidence for M-Theory, quantum technicolor force etc. All of these are exciting new possibilities for the LHC, and will revolutionise physics by introducing completely new physics.
    Damn! What rock have I been hiding under? Superpartner particles and quantum technicolor force. I hate to ask but etc does imply a lot more shit that I'm out of the loop on. I'm curious, you must still be working on your education if your still hoping to go into particle physics. Yes it's a very good time to be getting into the field and I wish you much success. May I ask what do you think will be the next LHC discovery that will get some publicity? Also, are you going to specialize to a sub-field of particle physics or some field of study which is not already crawling with physics hopefuls?
    Reply With Quote  
     

  12. #11  
    Forum Bachelors Degree PetTastic's Avatar
    Join Date
    Jul 2010
    Location
    London UK
    Posts
    421
    Quote Originally Posted by Dishmaster View Post
    Quote Originally Posted by arKane View Post
    Quote Originally Posted by Dishmaster View Post
    I would find it much more exciting, if at some point we realise that there is no such thing as Dark Matter. I am favouring a modified theory of gravity.
    At least not the dark matter they appear to be looking for. But I would be interested in hearing more about a possible modified theory of gravity. Do you have anything in mind?
    The non-relativistic framework is MOND (Modified Newtonian Dynamics). There is a relativistic expansion of this idea. Quite a number of publicatins can be found here:
    arXiv.org Search
    arXiv.org Search

    In particular:
    [astro-ph/0601431] Modified gravity without dark matter
    [astro-ph/0701848] The modified Newtonian dynamics-MOND-and its implications for new physics
    [0806.2585] From dark matter to MOND
    The problem with MOND as far as I understand at the Wikipedia user level, is that it has no answer for the shape of galaxies, inparticular the flat disks of spiral galaxies.
    I understand that in some galaxies, these disks are very thin compared to the size of the galaxy.
    Stars getting random gravitational kicks from each other or radiation pressure on dust should disperse the disk rapidly, but they seem stable for billions of years.
    I believe in nothing, but trust gravity to hold me down and the electromagnetic force to stop me falling through
    Physics is the search for the best model not the truth, as only mythical beings know that.
    Reply With Quote  
     

  13. #12  
    Forum Bachelors Degree x(x-y)'s Avatar
    Join Date
    Jul 2010
    Location
    UK
    Posts
    462
    Quote Originally Posted by arKane View Post
    Quote Originally Posted by x(x-y) View Post
    Of course, either way (finding Higgs Boson or not finding Higgs Boson) the future of particle physics is going to be incredibly exciting- a field which I am hoping to go into too! Obviously, I want some revolutionary "things" to be discovered at the LHC- and chances are they will be found- however, the Higgs is not the only particle being searched for, they're also looking for superpartner particles (to help to prove SUSY), evidence for superstring theory, evidence for M-Theory, quantum technicolor force etc. All of these are exciting new possibilities for the LHC, and will revolutionise physics by introducing completely new physics.
    Damn! What rock have I been hiding under? Superpartner particles and quantum technicolor force. I hate to ask but etc does imply a lot more shit that I'm out of the loop on. I'm curious, you must still be working on your education if your still hoping to go into particle physics. Yes it's a very good time to be getting into the field and I wish you much success. May I ask what do you think will be the next LHC discovery that will get some publicity? Also, are you going to specialize to a sub-field of particle physics or some field of study which is not already crawling with physics hopefuls?
    Indeed, I am 17 and currently doing my A Levels (in Physics, Maths and Chemistry) in order to get into university to study a degree course called "Physics with Particle Physics and Cosmology" hopefully- from there I shall decide what I am really interested in and go and do it!

    But, anyway, well I cannot be too sure about what next discovery at the LHC will attract the media- but I'd be willing to be that it's the current possible "Higgs Boson discovery"; it definitely will receive huge publicity (hopefully) if it gets passed the 3-sigma certainty level, if you're wondering- a 5-sigma event in particle physics is classed as a genuine discovery as this is where the chances of the event occuring due to some sort of statistical/systematic error is 1 in 1.7 million.
    "Nature doesn't care what we call it, she just does it anyway" - R. Feynman
    Reply With Quote  
     

  14. #13  
    Forum Professor arKane's Avatar
    Join Date
    Apr 2009
    Location
    Washington state
    Posts
    1,181
    Quote Originally Posted by x(x-y) View Post
    Indeed, I am 17 and currently doing my A Levels (in Physics, Maths and Chemistry) in order to get into university to study a degree course called "Physics with Particle Physics and Cosmology" hopefully- from there I shall decide what I am really interested in and go and do it!
    From the way you talk, I like your chances.

    But, anyway, well I cannot be too sure about what next discovery at the LHC will attract the media- but I'd be willing to be that it's the current possible "Higgs Boson discovery"; it definitely will receive huge publicity (hopefully) if it gets passed the 3-sigma certainty level, if you're wondering- a 5-sigma event in particle physics is classed as a genuine discovery as this is where the chances of the event occuring due to some sort of statistical/systematic error is 1 in 1.7 million.
    I was wondering a little, thank you. I have big doubts about the current theories of dark matter and dark energy and it's good to know someone in your position still has an open mind and wants to make a difference to how well we understand the universe.
    Reply With Quote  
     

  15. #14  
    Forum Bachelors Degree 15uliane's Avatar
    Join Date
    Feb 2011
    Location
    depends...
    Posts
    425
    I'm not an expert, but from what I know I've always thought that todays theorizing was all mathematical abstraction, and I humbly doubt that any of the proposed particles will be found.
    Reply With Quote  
     

  16. #15  
    Forum Professor arKane's Avatar
    Join Date
    Apr 2009
    Location
    Washington state
    Posts
    1,181
    Quote Originally Posted by 15uliane View Post
    I'm not an expert, but from what I know I've always thought that todays theorizing was all mathematical abstraction, and I humbly doubt that any of the proposed particles will be found.
    It seems likely that something new will be found, and whatever it is will be of great interest. But I won't be betting for or against anything, I'm just happy they have the LHC working and am looking forward to any new discoveries.
    Reply With Quote  
     

  17. #16  
    Forum Bachelors Degree PetTastic's Avatar
    Join Date
    Jul 2010
    Location
    London UK
    Posts
    421
    It will be a very interesting result, even if it finds nothing.
    If it does find something linked to dark matter my betting is the particle will have some very odd properties.
    We need something to explain the flat disks of spiral galaxies not just the rotation curve. To me, the rotation curve could just be a small side effect of the much larger nonlinear forces keeping the disk so thin.

    I have played with many variants of dark matter and modified gravity on particle systems. (Computer games programmer )
    My favorites are:
    A relatively light weight particle with limited penetration.
    Or a zero rests mass neutrino type particles that stops as a pair of heavy virtual particle when disturbed for real period of time, before continuing.
    Or particles that behave like an incompressible fluid. (no gravitional drag on stars)
    The simplest being just in falling gas with forces being proportional to the square of the velocity relative to the flow.

    I can't get simple weakly interacting heavy particles to work. They just cause too much gravitational drag on the stars, unless they are rotating with the galaxy. But if they are rotating with the galaxy, they would flatten out and this would show in gravitational lensing.
    Probably my models were just too simplistic.
    I believe in nothing, but trust gravity to hold me down and the electromagnetic force to stop me falling through
    Physics is the search for the best model not the truth, as only mythical beings know that.
    Reply With Quote  
     

Bookmarks
Bookmarks
Posting Permissions
  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •