
First images of collisions at 13 TeV - jonbaer
http://home.web.cern.ch/about/updates/2015/05/first-images-collisions-13-tev
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iamthepieman
I followed the links to the CMS, Atlas and other detectors that the images
appear to be from but couldn't find any information on what these images
actually mean. By reading the layman's descriptions (which I most certainly
am) I assume that the images show where along the "surface", if there is such
a thing, of the detector various particles were detected and the length of the
bars show either how much energy the particle(s) have or the density of
particles at that point.

Is there anywhere I can go to get a more detailed description of these without
delving into academic papers that I have no hope of understanding?

~~~
ISL
You've got the right general idea. It's a tricky thing to simultaneously
display three-dimensional tracks and the amount of energy deposited in each
detector system.

I'm surprised that Atlas and CMS don't have a better viewer's guide
immediately at hand, but perhaps this article will help:

[http://www.symmetrymagazine.org/breaking/2010/03/18/atlas-
ev...](http://www.symmetrymagazine.org/breaking/2010/03/18/atlas-event-
display-decoded)

~~~
rimunroe
I've worked at two accelerator facilities (RHIC and CEBAF) writing software
for doing particle tracking and pseudo-data generation, and I always wished
that they could divert more time into preparing articles like the one you
linked. They're super helpful to laypeople, especially family and friends, but
they're also great for getting students at universities interested in maybe
coming to pitch in.

Sadly, the lab personnel (especially those coordinating outreach) are
generally crazy overworked and don't have a lot of time, and the interns are
just too inexperienced and lack the requisite domain knowledge to do it
themselves.

~~~
kriro
If you ever feel like writing a paper on this I can highly suggest Ludwik
Fleck as a starting point (his writing on thought collectives). At least
that's where I started when I needed a concept of marketplace for ideas and
why laypeople matter.

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JonnieCache
Here's the LHC dashboard for your projector: [https://op-
webtools.web.cern.ch/op-webtools/vistar/vistars.p...](https://op-
webtools.web.cern.ch/op-webtools/vistar/vistars.php)

~~~
jonbaer
Are there others? This is the one I use:
[http://meltronx.com/index.html](http://meltronx.com/index.html)

~~~
JonnieCache
Wow, I haven't seen that. As you can see, my link goes straight to cern; you
appear to have found someone else's meta-dashboard.

The cern one has the dropdown in the top left that takes you to a lot of other
ones too.

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georgeglue1
What does the raw data that generates these renders look like, or do their
dashboards literally spit out images that look like that? I'm guessing their
instrumentation can roughly figure out what energy/size/charge of particle is
where, but the _how_ just seems like magic to me.

~~~
jessriedel
I highly recommend the "Particle Adventure" for lots of info about basic
particles physics that's accessible to the layman

[http://www.particleadventure.org/](http://www.particleadventure.org/)

In particular, starting at this page should give you an idea of how many
components there are and what sorts of information come out of them:

[http://www.particleadventure.org/component_detector.html](http://www.particleadventure.org/component_detector.html)

~~~
alfiedotwtf
+1 for Particle Adventure.

I wish more things were taught that way!

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XzetaU8
Once again, Scientific Linux delivers :P

~~~
pjmlp
I remember the days when that distribution was put out together. :)

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donpdonp
A description of the parts of the Large Hadron Collider, in 90's rap form, is
here:

[https://www.youtube.com/watch?v=j50ZssEojtM](https://www.youtube.com/watch?v=j50ZssEojtM)

~~~
krylon
Thanks, that was a nice one!

If one had to explain to somebody who has absolutely no clue whatsoever what
the LHC does and why, one could do worse than point them to this video. :)

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kordless
"Mr. Singularity, come here. I want to see you."

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guelo
How long will it take the black holes to swallow the earth?

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javajosh
Well, there's been some alarmism about AI recently, and in that same vein I'll
admit it - even with a physics degree I'm _uneasy_ about the LHC. By
definition we don't know what will happen. We are generating kinetic energies
that haven't been seen since literally the dawn of time. I would just be a lot
more comfortable if these experiments were being done in space, far away from
life. It's just that even 99.999% certainty that nothing catastrophic will
happen really isn't high enough considering the stakes.

EDIT: add 'kinetic'

~~~
ghshephard
Re: "We are generating kinetic energies that haven't been seen since literally
the dawn of time."

Is 13 TeV really considered a lot of energy in terms of what happens daily
with particles hitting our atmosphere?
[http://en.wikipedia.org/wiki/Cosmic_ray](http://en.wikipedia.org/wiki/Cosmic_ray)
seems to suggest that we've observed naturally occurring 3 × 10^20 eV, which
is a lot ( larger than 13 TeV (10^12).

~~~
yk
You have to look at center of mass energy, the energy actually available for
reactions in a collision. The collisions of ultra-high-energy-cosmic-rays
(UHECRs) with air occur at hundreds of TeV center of mass energy. And they may
be nucleons, in which case this energy is spread over several nuclei. So
assuming that Lorentz symmetry holds (probably the safest assumption in modern
physics), 13 TeV is in a similar ball park as UHECR collisions.

~~~
pif
> And they may be nucleons, in which case this energy is spread over several
> nuclei.

???

