Search Results for: lhc

ALICE Publishes!

Jacques Distler pointed out that ALICE has just published their first paper, only a little over a week after the beginning of the heavy ion phase of the LHC at CERN! Moreover, they are way ahead in energy of the previous heavy ion collision experiment (RHIC) and have verified “elliptic flow” (the main sign that the quark-gluon plasma behaves like a strongly coupled fluid, the big experimental surprise of some years back, with properties of a type that can be nicely captured using string theory models). Have a look at Jacques’ post here, and go directly to the paper of ALICE here.

Hurrah!

Please see my post from last week (“Experimental Excitement” was the apt title) about why I’m excited about all this!

-cvj Click to continue reading this post

Experimental Excitement!

alice_frist_run_dataWell, this week is a big week, in some ways. The Large Hadron Collider has gone into a new phase! For a while, the experiment has turned aside from the task of searching for the origin of mass (the Higgs Particle, or whatever it is that mediates the generation of the masses of elementary particles – see earlier posts, and features like this, etc) and is turning to heavy ion collisions. Rather than studying processes in which only a few particles at a time are interacting at super-duper-uber-high energies, the experiment will instead collide together the nuclei of lead atoms, so that you get lots of particles colliding together and creating a messy “soup” of high energy stuff all together. The goal is to understand the constituent nuclear particles (quarks and gluons) working collectively at high temperature (and low to moderate density), instead of focusing on issues concerning individual fundamental particles. Today (starting late yesterday, actually) is an exciting day because it marks the first step on the journey to probe deeper into this physics. The ALICE experiment has started looking at these collisions. See top right for some screen-shots of the mess of particle tracks that are left after the soup flies apart. The trick is to analyze all these tracks from millions of such collisions to work out the properties of the soup.

As you perhaps know from reading this blog, while of course I’m interested in the behaviour of fundamental particles and the origin of mass, and so on and so forth, I’m very interested in this nuclear issue too. Some of the most interesting work that […] Click to continue reading this post

Happy Higgs Hunting

lhcb_z_bosonIn case you were wondering, things are moving steadily along in the search for the Higgs boson, and in the general ramping up to study entirely new frontiers of particle physics. I noticed a couple of interesting articles today that give you a nice sample. The first, by Dick Ahlstrom in the Irish Times, and is about the announced “rediscovery” of the W and Z bosons at the Large Hadron Collider, by a team working at the LHCb experiment. (I personally think that the term “rediscovery” is somewhat misleading since it makes it seem like the community forgot where they (the key signatures of the unity of the electromagnetic and weak nuclear forces at high energy) were since their discovery in the early 80s, but let me not quibble too much.) The point is that experimental teams are refining their searching techniques while sifting through all the new data being produced in the collisions at the LHC, and one thing you need to do before you begin to look for new things (like the Higgs) is to make sure you can find and recognize old things. Especially very important old things. […] Click to continue reading this post

The Runaway Black Hole

In recent years there was all the nonsense about how scientists were going to accidentally make a black hole with the Large Hadron Collider that would runaway out of control…. we would not be able to stop it. We scientists would have tampered with the murky depths of Nature and awoken a monster we could not control. Naughty scientists that we are. The LHC has been colliding away at unprecedented energies, and last time I checked (you can too – click here) we’re ok.

gusher_oilI just realized something. Now we do have a runaway black hole! But it was created by naughty engineers, tampering with the murky depths of Nature and awakening a monster they cannot control. That gushing well 5000 feet below in the gulf of Mexico is a black hole […] Click to continue reading this post

An Exciting Asymmetry?

A big mystery in physics is why there is more matter than anti-matter. (Of course, which we call the matter and which we call the “anti-matter” is a… matter of convention. Take your pick.) It is hoped that there is some mechanism in the laws of physics (at a very basic level concerning particle interactions) that will become apparent that explains it. It’s also hoped that the mechanism itself might have some understandable origin too. The mechanism would operate in the first tiny fractions of a second of the universe’s life when the primordial soup of particles and antiparticles (created from, roughly speaking, the energy of the big bang) began to cool down as the universe expanded. Rather than them annihilating all back into energy again, the mechanism would create an imbalance between the two, giving rise to a matter-filled universe, from which we emerged. So what could be the mechanism, can we isolate it in our theories and in our experiments? Build a good model of it? Explain it?

This is all very first and foremost in people’s minds when there’s a new experiment switched on that is probing the unknown – the Large Hadron Collider. Well, actually, it has been recently announced that a suitable mechanism (or, more precisely, its […] Click to continue reading this post

Art and Science

e.coli image by shardcoreSome time back I wrote a post concerning E.Coli, and illustrated it with an image that I found on the web. The other day I learned more about the actual source of the image. The painting (click on image to enlarge) was from someone working under the name shardcore, and you can visit their site here. Notably, there are several pieces of work there, and a number of them are of science subjects, and scientists. Shardcore writes interesting notes for some of the work too.

The work is overall quite fascinating, striking, and often very aesthetically engaging. I recommend having a good long look around. To tease you to go there, let me point out a (topical) one for some of us with eyes on the LHC. A painting of Peter Higgs:

[…] Click to continue reading this post

Other Accelerator Physics is Available

The alternative title for this post was going to be “Closing in on Unobtanium”, but I realized that it might be better to explicitly remind you that the Large Hadron Collider, understandably featuring in the news a lot these days, is not the only particle accelerator in operation. Such machines are routinely at work all over the world (for example, supplying hospitals with radioactive materials used in medical diagnosis), and doing various kinds of key research (recall as another example the RHIC physics I’ve told you a bit about in relation to certain applications of string theory). One such set of investigations involves finding new heavy elements, extending the periodic table of elements. Yes, just like happened with Pluto’s demotion and its resulting effect on your internalized list of planets in the solar […] Click to continue reading this post

A Return

gladioliI find myself back in Los Angeles for a bit, putting Walkabout mode on pause. Perhaps to do my laundry, perhaps to chair the committee of the upcoming Ph.D. defense of my student, Tameem, perhaps to be able to sit outside in the early morning sun in a T-shirt and blog over breakfast.

The garden is full of weeds and flowers, and all is well with the world, albeit a bit blurry due to my jetlag.

Anyway, a few random things to note:

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mourning_dovesAnother Spring is here, in full force. I once again snort in exasperated laughter at the bizarre claim so very many people make about Los Angeles (Southern California more generally) not having seasons, as I marvel at all the many signs of it screaming for attention. As a random example, I’m observing some mourning doves eyeing me up from nearby as they try to decide whether I’m a threat to their potential nesting sites that they are checking out. Seems that at least one pair is rather impressed with my cluster of strelitzia nicolai and want to move in. I want to tell them that I’m not the problem, but the fact that they’d be in plain sight of the crows/rooks/ravens/winged-Nazgul that pass by here a lot will be. I’ve seen them strike nests in those trees from previous years and scoop up a tasty warm meal.

* * *

Eight hours of jetlag means only one thing: […] Click to continue reading this post

Wham!

aliceWell, a very gentle sort of wham. Yesterday the Large Hadron Collider at CERN had its first collisions of protons! It is a warm start, making sure everything is working before ramping up the energies to regimes where we hope to see new physics, but it is a very exciting milestone nonetheless*. Recall that a few days back they hit the landmark of getting the machine to circulate beams again for the first time. (If you’ve forgotten what all of this is for, please search the blog for “LHC” and/or look in the related posts list at the bottom of this one.) Above right is a visual reconstruction of some of the collision data seen at the ALICE detector, and you can see more of this sort of data at CERN’s website (from where I got this graphic).

From the press release: […] Click to continue reading this post

Coming Around the Bend Again

0911187_135-a5-at-72-dpiIt was in the news today, I’m told*. The LHC is circulating beams again!! This is exciting news indeed. Look out for a press conference on Monday, and here is a press release about the event that took place yesterday. Also, collisions are said to be going to happen next week! This is all very wonderful.

I’m mid-travel, and should be sleeping for an early start tomorrow, and so I’ll simply point over to […] Click to continue reading this post

Brian Cox on Colbert

brian_cox_colbertPhysicist Brian Cox had a bit of fun on Colbert a few nights back*. At Stephen Colbert’s prompting he mentions the nonsense about time travel and the Higgs boson, (which I decided not to blog since it was so frustratingly idiotic and had no business in, for example the science section of a national newspaper not the least because it just serves to confuse readers with even more nonsense about the Large Hadron Collider (LHC) than they already have been) and then has a blast (it seems) discussing the importance of Special Relativity, [tex]E=mc^2[/tex], and why you should care, which is the subject of his new book with Jeff Forshaw.

Unfortunately he seems, at one point, to fall into the usual (high-horsed physicist) pattern of dismissing another legitimate science endeavour (food science in this case) as not science, but I’ll give him the benefit of the doubt and assume it was just a joke made in the heat of the moment. He’s too smart and likeable a guy, (and a very good public spokesperson for science education by all accounts and past appearances), to be quite so dismissive. Riffing fast and furious with Colbert will no doubt sometimes produce such slips.

By the way (and Brian does not get this wrong, but does not get the chance to say it, and I’m sure he knows it) people often get left with the impression from press releases about the LHC (see related posts below for lots of LHC background) and other […] Click to continue reading this post

Science and Space on Mayo

On the BBC’s Daily Mayo the other day there was a science focus! Scientists Brian Cox and Jeff Forshaw joined Simon to talk about their new book Why Does [tex]E=mc^2[/tex]? that looks at Einstein’s famous equation which explores the principles of physics through everyday life. Commander Lee Archambault, currently on … Click to continue reading this post

News From The Front, VII: What is Fundamental, Anyway?

One of the words I dislike most in my field – or more accurately, a common usage thereof – is “fundamental”. This is because it is usually used as a weapon, very often by people in my area of physics (largely concerned with particle physics, high energy physics, origins questions and so forth), to dismiss the work of others as somehow uninteresting or irrelevant. image by I don’t like this. Never have. Not only is it often allied to a great deal of arrogance and misplaced swagger, it is often just plain short-sighted, since you never know where good ideas and techniques will come from. A glance at the history of physics shows just how much cross-pollination there is between fields in terms of ideas and techniques. You never know for sure where valuable insights into certain kinds of problems may come from.

Fundamental physics is a term I used to hear used a lot to refer to particle physics (also called high energy physics a lot more these days). This was especially true some years back when I was an undergraduate in the UK, and it persisted in graduate school too, and is still in use today, although I think it is declining a bit in favour of less loaded terms. Somehow, a lot of particle physics is regarded as being all about the “what is everything made of at the very smallest scales” sort of question, first discussing atoms, and then atoms being made of electrons surrounding a nucleus, and the nucleus being made of protons and neutrons, and those in turn being made of quarks, and so on, in this was arriving at a list of “fundamental” particles. There’s the parallel discussion about the “fundamental” forces (e.g., electromagnetism and the nuclear forces) being described in terms of exchanges of particles like photons, gluons, and W and Z particles and so forth. There’s no real harm in the use of the term fundamental in this context, but this is about where the word gets elevated beyond its usefulness and starts becoming a hurdle to progress, and then a barrier. Somehow, “fundamental”, meaning “building block” gets turned, oddly, into “most important”. The issue of what the smallest building blocks are gets elevated to the most important quest, when it is in reality only a component of the story. It is rather like saying that the most important things about the Taj Mahal are the beautiful stones, tiles, and other components from which it is constructed.

Perspectives have evolved a bit since my salad days, with the rise of wider […] Click to continue reading this post

Tales From The Industry XXVIII – Angels, Demons, and Antimatter

So, apparently there is physics in the upcoming huge film Angels and Demons (and presumably the book). Lots of it. I did not know that until recently. So imagine my surprise a few months ago when I got a message from a producer (Natalie Artin of Prometheus Pictures) of a documentary about it, asking if I’d like to contribute, talking about aspects of the physics.

They wanted me to talk about anti-matter. This is as a result of finding a blog post of mine over on Correlations, entitled “Not Science Fiction”, which starts:

Anti-matter. Seeing the previous word, you immediately glance back at the title, right? Strangely, it has been 80 years since the discovery of anti-matter, and we use it routinely in our technology. Nevertheless, anti-matter is still thought of as something from science fiction (and mostly bad science fiction at that).

dirac_equation It all goes back to one of my favourite theoretical physicists, Paul Dirac, and you might like how he found it (roughly). He essentially did it by […]

I agreed to talk, if I could focus on one of the main issues of my post: That anti-matter is not weird stuff of science fiction, but actual routine science…. so routine that it is used commonly in medical diagnosis, for example. The “P” in PET scans stands for “positron”. The positron is the anti-electron. (The “E” does not […] Click to continue reading this post