## Greek BlogNovember 1, 2010

Posted by dorigo in Blogroll, internet, language, news, personal, physics, science.

I had forgotten to link it from here, but the internet always provides a chance for redemption. So here I go. A couple of months ago I have opened another wordpress blog, where I write on particle physics – in Greek. This is a rather extravagant choice, and I think I need to spend a few words explaining it.

First of all, there is my love of the language, which I have been studying for two years. It is a difficult language to master, due to the interplay of several factors: the different alphabet, the enormous wealth of words, and the rather quick evolution of rules and uses. Maybe because of these challenges, I have found it quite entertaining to get on top of it.

The second reason for writing in Greek is, in fact, that I have yet a lot to learn, and I think that writing about science is a very good exercise, allowing me to find a solution to the translation problems I may encounter if I discuss about my job – physics – in that language.

The third reason is that I think there is no offer whatsoever in the web for a blog about particle physics in Greek (if you know any, let me know). So I might just try to fill that hole myself.

In short, the new blog is an experiment. I do not know, nor can predict, how long it will last; for now, if you know modern Greek please stop by. Below is a list of my recent efforts:

## ICHEP blogJuly 12, 2010

Posted by dorigo in astronomy, Blogroll, cosmology, internet, news, physics, science.

Just one line here to mention that since May there is a new blog out there – a temporary blog that will cover the end of July event in Paris – the International Conference on High Energy Physics -, how we get there, and the aftermath. The effort includes several well-known bloggers in high-energy physics, and is definitely worth following.

You can visit it here.

## Some recent posts you might want to readMarch 6, 2010

Posted by dorigo in Blogroll, internet, news, physics, science.
Tags: , , , , , , , ,

As the less distracted among you know, I have moved my blogging activities to scientific blogging last April. I wish to report here a list of interesting posts I have produced there in the course of the last few months (precisely, since the start of 2010). They are given in reverse chronological order and with zero commentary – come see if you are curious.

## One million hitsJune 29, 2009

Posted by dorigo in Blogroll, internet, news, personal, physics.

While this site has been basically inactive for over two months, it still draws some residual traffic due to google searches and links; so the hit counter has continued to click after April 15th, although at a rate of roughly a third of what it did before.

Today’s news is that we got past the millionth click. Thanks to everybody for your interest in particle physics and in my reports. Please visit www.scientificblogging.com/quantum_diaries_survivor to keep up-to-date with particle physics!

## Post summary – April 2009May 1, 2009

Posted by dorigo in astronomy, Blogroll, cosmology, internet, news, personal, physics, science, social life.
Tags: , , , , , , , , , , , ,

As the less distracted among you have already figured out, I have permanently moved my blogging activities to www.scientificblogging.com. The reasons for the move are explained here.

Since I know that this site continues to be visited -because the 1450 posts it contains draw traffic regardless of the inactivity- I am providing here monthly updates of the pieces I write in my new blog here. Below is a list of posts published last month at the new site.

The Large Hadron Collider is Back Together – announcing the replacement of the last LHC magnets

Hera’s Intriguing Top Candidates – a discussion of a recent search for FCNC single top production in ep collisions

Source Code for the Greedy Bump Bias – a do-it-yourself guide to study the bias of bump fitting

Bump Hunting II: the Greedy Bump Bias – the second part of the post about bump hunting, and a discussion of a nagging bias in bump fitting

Rita Levi Montalcini: 100 Years and Still Going Strong – a tribute to Rita Levi Montalcini, Nobel prize for medicine

The Subtle Art of Bump Hunting – Part I – a discussion of some subtleties in the search for new particle signals

Save Children Burnt by Caustic Soda! – an invitation to donate to Emergency!

Gates Foundation to Chat with Bloggers About World Malaria Day – announcing a teleconference with bloggers

Dark Matter: a Critical Assessment of Recent Cosmic Ray Signals – a summary of Marco Cirelli’s illuminating talk at NeuTel 2009

A Fascinating New Higgs Boson Search by the DZERO Experiment – a discussion on a search for tth events recently published by the Tevatron experiment

A Banner Worth a Thousand Words – a comment on my new banner

Confirmed for WCSJ 2009 – my first post on the new site

## Just a linkApril 5, 2009

Posted by dorigo in Blogroll, news, physics, science.
Tags: , ,

I read with amusement (and some effort) a spanish account by Francis (th)E mule of Michael Dittmar’s controversial seminar of last March 19th. I paste the link here for several reasons: since I believe it might be of interest to some of you, to have a place to store it, and because I am not insensitive to flattery:

“Entre el público se encontraba Tomasso Dorigo […] (r)esponsable del mejor blog sobre física de partículas elementales del mundo”

Muchas gracias, Francis -but please note: my name spells with two m’s and one s!

## What’s hot aroundFebruary 10, 2009

Posted by dorigo in astronomy, Blogroll, cosmology, internet, italian blogs, mathematics, news, physics, science.
Tags: , , , , ,

For lack of interesting topics to blog about, I refer you to a short list of bloggers who have produced readable material in the last few days:

• The always witty Resonaances has produced an informative post on Quirks.
• My friend David Orban describes the recently-instituted singularity University
• Stefan explains other types of singularities, those you can find in your kitchen!
• Dmitry has an outstanding post out today about the physics of turbulence, with four mini-pieces on the Reynolds number, viscosity, universality and intermittency. Worth a visit, if even just for the pics!
• Marco discusses the long winter of LHC. Sorry, in italian.
• Peter discusses the same issue in English.
• Marni points out a direct explanation of the Pioneer anomaly with the difference between atomic clock time and astronomical time. Or, if you will, a change of the speed of light with time!

## Black holes hype does not decayFebruary 3, 2009

Posted by dorigo in astronomy, Blogroll, cosmology, humor, news, physics, politics, religion, science.
Tags: , ,

While the creation of black holes in the high-energy proton-proton collisions that LHC will hopefully start providing this fall is not granted, and while the scientific establishment is basically unanimous in claiming that those microscopical entities would anyway decay in a time so short that even top quarks look longevous in comparison, the hype about doomsday being unwittingly delivered by the hands of psychotic, megalomaniac CERN scientists continues unhindered.

Here are a few recent links on the matter (thanks to M.M. for pointing them out):

The source of the renewed fire appears to be a paper published on the arxiv a couple of weeks ago. In it, the authors (R. Casadio, S. Fabi, and B. Harms) discuss a very specific model (a warped brane-world scenario), in whose context microscopic black holes might have a chance to survive for a few seconds.

Never mind the fact that the authors say from the very abstract, as if feeling the impending danger of being strumentalized, “we argue against the possibility of catastrophic black hole growth at the LHC“. This is not the way it should be done: you cannot assume a very specific model, and then draw general conclusions, because others opposing your view may always use the same crooked logic and reverse the conclusions. However, I understand that the authors made a genuine effort to try and figure out what could be the phenomenology of microscopic black holes created in the scenario they considered.

The accretion of a black hole may occur via direct collision with matter and via gravitational interactions with it. For microscopic black holes, however, the latter (called Bondi accretion) is basically negligible. The authors compute the evolution of the mass of the BH as a function of time for different values of a critical mass parameter $M_c$, which depends on the model and is connected to the characteristic thickness of the brane. They explicitly make two examples: in the first, when $M_c=100 kg$,  a 10 TeV black hole, created with 5 TeV/c momentum, is shown to decay with a roughly exponential law, but with lifetime much longer -of the order of a picosecond- than that usually assumed for a micro-BH evaporating through Hawking radiation. In the second case, where $M_c=10^6 kg$, the maximum BH mass is reached at $3.5 \times 10^{21} kg$ after about one second. Even in this scenario, the capture radius of the object is very small, and the object decays with a lifetime of about 100 seconds. The authors also show that “there is a rather narrow range of parameters […] for which RS black holes produced at the LHC would grow before evaporating“.

In the figure on the right, the 10-base logarithm of the maximum distance traveled by the black hole (expressed in meters) is computed as a function of the 10-base logarithm of the critical mass (expressed in kilograms), for a black hole of 10 TeV mass produced by the LHC with a momentum of 5 TeV/c. As you can see, if the critical mass parameter is large enough, these things would be able to reach you in your bedroom. Scared ? Let’s read their conclusions then.

“[…] Indeed, in order for the black holes created at the LHC to grow at all, the critical mass should be $M_c>10^5 kg$. This value is rather close to the maximum compatible with experimental test of Newton’s law, that is $M_c=10^6 kg$ (which we further relaxed to $M_c=10^8 kg$ in our analysis). For smaller values of $M_c$, the black holes cannot accrete fast enough to overcome the decay rate. Furthermore , the larger $M_c$ is taken to be, the longer a black hole takes to reach its maximum value and the less time it remains near its maximum value before exiting the Earth.

We conclude that, for the RS scenario and black holes decribed by the metric [6], the growth of black holes to catastrophic size does not seem possible. Nonetheless, it remains true that the expected decay times are much longer (and possibly >>1 sec) than is typically predicted by other models, as was first shown in [4]”.

Here are some random reactions I collected from the physics arxiv blog -no mention of the author’s names, since they do not deserve it:

• This is starting to get me nervous.
• Isn’t the LHC in Europe? As long as it doesn’t suck up the USA, I’m fine with it.
• It is entirely possible that the obvious steps in scientific discovery may cause intelligent societies to destroy themselves. It would provide a clear resolution to the Fermi paradox.
• I’m pro science and research, but I’m also pro caution when necessary.
• That’s what I asked and CERN never replied. My question was: “Is it possible that some of these black might coalesce and form larger black holes? larger black holes would be more powerful than their predecessors and possibly aquire more mass and grow still larger.”
• The questions is, whether these scientists are competent at all, if they haven’t made such analysis a WELL BEFORE the LHC project ever started.
• I think this is bad. American officials should do something about this because if scientists do end up destroying the earth with a black hole it won’t matter that they were in Europe, America will get the blame. On the other hand, if we act now to be seen dealing as a responsible member of the international community, then, if the worst happens, we have a good chance of pinning it on the Jews.
• The more disturbing fact about all this is the billions and billions being spent to satisfy the curiosity of a select group of scientists and philosophers. Whatever the results will yield little real-world benefit outside some incestuous lecture circuit.
• “If events at the LHC swallow Switzerland, what are we going to do without wrist watches and chocolate?” Don’t worry, we’ll still have Russian watches. they’re much better, faster even.

It goes on, and on, and on. Boy, it is highly entertaining, but unfortunately, I fear this is taking a bad turn for Science. I tend to believe that on this particular issue, no discussion would be better than any discussion -it is like trying to argue with a fanatic about the reality of a statue of the Virgin weeping blood.

… So, why don’t we just shut up on this particular matter ?

Hmm, if I post this, I would be going against my own suggestion. Damned either way.

Posted by dorigo in Blogroll, internet, personal.
Tags: , ,

Congratulations to Doug, who left comment number 10,000 on this blog yesterday.The number is subtracted of all the spam comments and of the extremely few comments I have felt compelled to censor in the past (mostly for their offensive content).

I unfortunately cannot offer free services to him for the occasion, since this blog is a free service already.

## What is a glueball ?January 4, 2009

Posted by dorigo in Blogroll, physics, science.
Tags: , , ,

This post is just a placeholder for a link and an invitation for you to join me and ask Marco Frasca to further his already enlightening discussion of glueballs, as I already did in the comments thread of his post.

The subject is indeed fascinating: gluonic matter. A condensate of bosons. Asymptotic states (particles) made of no fermions. Matter as we never experienced it.

Glueballs are (thought to be) bound states of gluons. The gluon, the carrier of strong interactions, is a massless boson, and it is charged with the attribute it mediates: colour. Because of the colour charge of gluons, these particles can interact with one another, giving rise to the fascinating properties of Quantum Chromodynamics, the asymptotic freedom properties of bound states of quarks, and the infrared slavery – the impossibility of obtaining free coloured objects (quarks or gluons). The non-abelian nature of the SU(3) group underlying quantum chromodynamics is a source of the difficulties of calculating the low-energy limit of the theory.

The self-interaction properties of gluons creates the possibility of a color-neutral state made of gluons only: glueballs. Glueball properties, however, cannot be computed with perturbation theory, and these remain very mysterious objects over thirty years after QCD was understood in its workings. Only with lattice calculations -you know, discretizing space and computing path integrals with finite sums- can the glueballs be understood. But Marco hints at methods that allow a deeper understanding: methods based on condensed matter physics. We are all ears!