Search found 76 matches
- Sat Jan 23, 2010 12:44 pm
- Forum: Controversial topics
- Topic: Several biggest errors of particle physicists.
- Replies: 1135
- Views: 1381794
Re: Several biggest errors of particle physicists.
Wormholes have space-time metrics, which is close to Kaluza-Klein space-time with extra-dimension, uniting gravity and electromagnetism. IF what you mean by this is that you are interpreting a Reissner-Nordstrom metric as a KK system (fair enough), then you are probably misunderstanding the Einstei...
- Fri Jan 22, 2010 11:53 pm
- Forum: Controversial topics
- Topic: Several biggest errors of particle physicists.
- Replies: 1135
- Views: 1381794
Re: Several biggest errors of particle physicists.
Stephen - sure, beyond a certain point maybe it's a matter of taste which (correct) line of argument one personally finds most convincing, depending on the evidence and theoretical tools used. But I must say I find it astonishing that one could regard the process of black hole *production* (which re...
- Fri Jan 22, 2010 11:27 pm
- Forum: Controversial topics
- Topic: Several biggest errors of particle physicists.
- Replies: 1135
- Views: 1381794
Re: Several biggest errors of particle physicists.
Stephen, if you don't believe in Hawking radiation, there are other chains of reasoning - for instance based on astrophysical evidence. You can find the papers linked from the following wikipedia page (they are not that hard to read, at least if only you want to get the gist): http://en.wikipedia.or...
- Fri Jan 22, 2010 7:49 pm
- Forum: Controversial topics
- Topic: Several biggest errors of particle physicists.
- Replies: 1135
- Views: 1381794
Re: Several biggest errors of particle physicists.
March_Hare, even if a mini-BH was at rest it would be no danger because its temperature would be extremely high (for an uncharged black hole, it would be inversely proportional to the mass, and the mass is tiny). It will therefore radiate and lose energy, hence lose mass. This means it gets hotter! ...
- Fri Jan 22, 2010 2:34 pm
- Forum: Controversial topics
- Topic: Several biggest errors of particle physicists.
- Replies: 1135
- Views: 1381794
Re: Several biggest errors of particle physicists.
Here is the English translation of Fortov's introductory review article: http://www.iop.org/EJ/article/1063-7869/52/6/R08/PHU_52_6_R08.pdf?request-id=c943ce88-3e73-4a7c-8374-15966a961552 I note that in this article, Fortov is very positive about the LHC! The relevant passage Ivan cited is on page 25...
- Fri Jan 22, 2010 10:54 am
- Forum: Controversial topics
- Topic: Several biggest errors of particle physicists.
- Replies: 1135
- Views: 1381794
Re: Several biggest errors of particle physicists.
That diagram of a "magnetic hole" is bizarre. If you had electrons and positrons on the same orbit, they would annihilate. Quite apart from the question of what is supposed to cause those orbits (and worse, the lattice-like arrangement) in the first place.
- Mon Jan 11, 2010 6:21 pm
- Forum: Science
- Topic: Can black holes grow?
- Replies: 36
- Views: 49574
Re: Can black holes grow?
>How do black holes ever grow? >For is it not at the event horizon where time freezes (according to einsteins theory) for >masses speeding up to the velocity of light? Clocktime at the horizon freezes relative to our >clocks. Then, how can black holes ever accumulate mass in the timeperiods our cloc...
- Thu Dec 17, 2009 1:30 pm
- Forum: LHCb
- Topic: Q&A with a LHCb expert
- Replies: 6
- Views: 17632
Q&A with a LHCb expert
From the chat... [20:53] <photino> CMS has also rediscovered the pion http://cms.web.cern.ch/cms/Media/Publications/CMStimes/2009/12_14/images/K0s.png [20:53] <photino> lhcb was faster... [20:54] <Anitusar> lhcb also found the Ks and lambda :) [20:54] <photino> sorry that's actually the K_0 producti...
- Tue Dec 15, 2009 12:53 am
- Forum: LHCb
- Topic: Event Display
- Replies: 12
- Views: 34044
Re: Event Display
OK, based on the above, a first stab at colour ID's (it's a bit hard to tell due to the lack of resolution around the velo in particular): light purple = TTracks turqoise = downstream dark blue = long tracks grayish light blue = upstream dark purple = RICH photons light green = also TTracks? green =...
- Sun Nov 29, 2009 12:34 pm
- Forum: New Users Start Here
- Topic: Fascinating Facts about the LHC
- Replies: 13
- Views: 42111
Re: Fascinating Facts about the LHC
One of my favourite facts: Remember how metal contracts as it gets colder? When the LHC is cooled down, each sector shrinks by about 10 metres in length. This means the entire ring shrinks by 80m! (almost the length of a football field). (This change has to be absorbed - thats why components are joi...
- Sat Nov 28, 2009 1:15 am
- Forum: New Users Start Here
- Topic: What do the displays mean ?
- Replies: 87
- Views: 248603
Re: What do the displays mean ?
Neat summary of the basic "LHC operations" sequence: After re-cycling, the machine is ready for injection of 450 GeV protons This should take ~15 minutes The beams are ramped to nominal energy (3.5 TeV in 2010) This takes about ½ hours Beams are prepared for physics: Squeeze to make them smaller at ...
- Sat Nov 28, 2009 12:35 am
- Forum: The Accelerator
- Topic: What does ... mean?
- Replies: 28
- Views: 46302
Re: What does ... mean?
This contains a nice explanation of luminosity and intensity... there's lots and lots of detail there.
https://edms.cern.ch/file/445831/5/Vol_1_Chapter_3.pdf
roughly speaking,
intensity = number of particles in a bunch
luminosity = number of particles going through a cm^2 per second
https://edms.cern.ch/file/445831/5/Vol_1_Chapter_3.pdf
roughly speaking,
intensity = number of particles in a bunch
luminosity = number of particles going through a cm^2 per second
- Thu Nov 26, 2009 3:47 pm
- Forum: New Users Start Here
- Topic: What do the displays mean ?
- Replies: 87
- Views: 248603
Re: What do the displays mean ?
Re the BTV displays on page 1: it appears the BTV images are produced by lowering a scintillating screen into the beam. Since this somewhat degrades the beam itself, the screen is only lowered into the beam when measurement is required. I suspect some of the images we are seeing are artifacts of BTV...
- Wed Nov 25, 2009 11:19 pm
- Forum: New Users Start Here
- Topic: What do the displays mean ?
- Replies: 87
- Views: 248603
Re: What do the displays mean ?
Or maybe the red bar (like for instance at the moment on the right at BTVST.A4R8.B2) is a beam that is not very collimated? Then the red bar on the left display (BTVST.A4L2.B1) would also be the presently circulating second beam? Ah well, maybe someone from CERN will enlighten us at some point...
- Wed Nov 25, 2009 10:27 pm
- Forum: New Users Start Here
- Topic: What do the displays mean ?
- Replies: 87
- Views: 248603
Re: What do the displays mean ?
This site explains the codes above the four images on LHC Page1. They denote the beam TV camera the image is coming from.
http://ab-dep-bi-pm.web.cern.ch/ab-dep- ... ies.BTVLHC
It would be nice to understand better the actual image itself
http://ab-dep-bi-pm.web.cern.ch/ab-dep- ... ies.BTVLHC
It would be nice to understand better the actual image itself