What? Strangelets from the LHC?

[Antranik]

Can anyone analyze this article? It is well beyond my understanding of the concepts, but maybe not for some of you. The address is... cerntruth.com /?p=125

 

[Giggywig]

Link for the lazy.

 

[Dancing David]

Can anyone analyze this article? It is well beyond my understanding of the concepts, but maybe not for some of you. The address is... cerntruth.com /?p=125

Welcome Antranik!

Um, despite some silly people cosmic rays produce these kinds of energies in our atmosphere.

they don't even get Vonnegut's book title right Cat's Cradle^WP not Cats and Cradle

 

[Fnord]

Woo for the sceptical.

 

[MattusMaximus]

http://skepticalteacher.wordpress.c...e-hadron-collider-will-not-destroy-the-earth/

 

[cj.23]

http://skepticalteacher.wordpress.c...e-hadron-collider-will-not-destroy-the-earth/

Deals with black holes though, but does not mention strangelets. Good article though. I wrote this on another forum, maybe bilge as my physics is not up to task - but my research skills are not bad?

Why hasn't the Earth been destroyed by cosmic rays some time over the last 4.5 billions years?

http://en.wikipedia.org/wiki/Oh-My-God_particle

3 x 10²⁰ eV vs 14 x 10¹² eV :lol:

I thought until today that was a good answer (the moon I'd probably use) but then I reaad the 2003 "worst case scenario" report -- indeed http://arxiv.org/abs/hep-ph/9910471v1 and http://arxiv.org/abs/hep-ph/9910333v3 back in the 1990's seemed to support it. The 2003 report however, deliberately and I stress this designed to look at "worst case" scenarios ( http://cdsweb.cern.ch/record/613175/files/p1.pdf ) states

We conclude that the moon data alone can exclude the possibility of creating dangerous objects behaving like normal hadronic systems, but strangelets with completely exotic properties cannot be ruled out...

To summarize, under plausible assumptions the cosmic-ray data exclude the possibility of dangerous processes in heavy-ion colliders like RHIC or the LHC, but the worst-case scenario cannot be excluded based on these data alone.

Now before you think I have gone off to woo woo land, nope, these two paragraphs I have excerpted have an awful lot in between, and explain the assumptions and issues clearly, logically, and rather well, and show why the risks appear small based on the accumulated evidence. However, wht si important here, is we can not actualy say (or could not in 2003) that there was no risk, in fact, given the fact we do not have a perfect understanding of physics (or we would not need the LHC in the first place), we simply can't. The follow up in 2008 http://iopscience.iop.org/0954-3899/35/11/115004/ sounds reassuring -- but I have not read it yet. Anyone?

There are other thinsg that surprised me in the paper: I finally understood what the LHC-phobes were on about when they talked about stationary particles (in most high energy collisions kinteic energy carries the particles away from each other, in the LHC they stick around, sort of!), and why they worry when the RHIC might seem more dangerous in this area in theory (basically we are planning experiments with heavier elements,which was pretty much the point of the LHC after all, to collide hadrons? Well hadrons is quarks, and quarks can be strange. ) Strangelet production may not be likely, but it certainly not inconcievable -- it's the decay rate and chance of interaction that matters, and for that we need to read more.

What I have read is the 2008 http://environmental-impact.web.cer...bjects/LHCSafety/LSAGSummaryReport2008-en.pdf Enironmental Impact report. This reaffirms the notion that cosmic rays do provide us with a template - but then cites the 2003 paper, without noting the caveats.

I never just dismiss people at kooks - I kept digging, and struck gold - http://lsag.web.cern.ch/lsag/LSAG-Report.pdf

Calculations for heavy-ion collisions at the LHC give a similar
effective temperature and a lower net density of baryons than at RHIC. This means that the LHC could only produce strangelets at a lower rate, if they exist at all.

We conclude by reiterating the conclusion of the LHC Safety Group in 2003 [1]: there is no basis for any conceivable threat from the LHC. Indeed, theoretical and experimental developments since 2003 have reinforced this conclusion.

Well that seems pretty definitive. Assuming that the RHIC did not destroy us in it's years of operation and i failed to notice. One assumes that the RHIC has produced impacts with atomic numbers greater than 10 if so, we should be ok. If not, well the RHIC is not a guide, as strangelet formation is not hypothesised to occur below that range anyway? Yes, I seem to recall gold being used (79 unless i'm misremebering). So that seems reassuing to me.

The real clincher seems to be that strangelets can not be stable in high temperatures

For this reason, the likelihood of strangelet production in relativistic heavy-ion collisions can be compared to the likelihood of producing an icecube in a furnace... The total number of heavy-ion collisions created at the LHC will be comparable to the total number of heavy ion collision created at RHIC. The LHC will be at least as hot a furnace as RHIC, in the sense that the systems produced in heavy-ion collisions at the LHC will have an effective temperature that is similar to that produced at RHIC. This is one factor that makes strangelet production no more likely at the LHC than at RHIC.

The risk was perhaps greater in older experiments, back in the 1980's, at lower temperatures. Still I find this ressuring

A thousand heavy-ion collisions would already suffice for a first test of the thermal model which describes heavy-ion collisions as a particle furnace. This will be among the first data analyses done in the LHC heavy-ion programme, and will immediately provide an experimental confirmation of the basic assumptions on which the safety argument is based.

So once we start in November some heavy ion collisions should soon provide theoretical data that will put this to bed? My only puzzlement left comes from my recent reading that the highest energy cosmic rays are actualy protons, not heavy ions - http://www.insidescience.org/research/scientists_prove_cosmic_rays_are_made_of_protons Er, I wonder is that has been taken in to account? I think we get heavy ion collisons up to about 2.6ev, and the LHC is running at 2.7ev?

To be honest I never worried about strangelets or black holes. Only false vacuum collapse ever worried me, and I was reassured on that by something Lord Rees wrote and let that anxiety go a couple of years ago. Stil, I hope my little review of the safety data proves ressuring to those members of the forum who like me are not scientists, and it's a bit of a shame that it was left to the resident arch-woo (parapsychologist/theologian) to try and give a detialed explanation of why we are unlikely to be destroyed by the LHC. I hope the more scientifically literate, and especially the physicists, will forgive my ramblings. Do correct my mistakes, I like learning about stuff! :cheers:

cj x