News from the CDF and PAMELA experiments

[Thanks to Peter Woit]

Since I am not expert in particle/astroparticle high energy physics, I will not comment on those results, but I admit to find them quite interesting, so I will link them here for my record. You are encouraged to read Woit‘s and Dorigo‘s (CDF collaborator) posts on the first news and the Resonaances blog post on the second one. The technical papers are linked below:

Study of multi-muon events produced in p-pbar collisions at sqrt(s)=1.96 TeV [CDF homepage here]

Observation of an anomalous positron abundance in the cosmic radiation [PAMELA homepage here]

Update: Discussions also going on here.

Update: See a new post over at Cosmic Variance by John Conway, another CDF collaborator.

Update: Well-known physicist Nima Arkani-Hamed clarifies the genesis of and motivation for his recent papers (published a few weeks before the CDF result) # ## over at Dorigo’s blog. His response denies previous suggestions that he and his collaborators had access to CDF results before their publication. Dorigo writes a new post on this here.

Update: A new post by Woit here.

Final word: I will no longer add further updates. You have plenty of places over the blogosphere to follow this. I must get back to work.

The right attitude

In 1999 I finished my three-volume book on the quantum theory of fields
(cited here as “QTF”), and with unaccustomed time on my hands, I set
myself the task of learning in detail the theory underlying the great progress
in cosmology made in the previous two decades. Although I had done some
research on cosmology in the past, getting up to date now turned out to take
a fair amount of work. Review articles on cosmology gave good summaries
of the data, but they often quoted formulas without giving the derivation,
and sometimes even without giving a reference to the original derivation.
Occasionally the formulas were wrong, and therefore extremely difficult
for me to rederive. Where I could find the original references, the articles
sometimes had gaps in their arguments, or relied on hidden assumptions, or
used unexplained notation. Often massive computer programs had taken
the place of analytic studies. In many cases I found that it was easiest to
work out the relevant theory for myself.
This book is the result.

Weinberg, Cosmology (preface)

Click-the-links!

For your diversion. [Via Science in the News of the great American Scientist magazine]

What Makes Science ‘Science’?

The Sloan Digital Sky Survey’s 3-D guide to the final frontier

News from Saturn’s moon Enceladus

Primordial soup lives again – the origin of life… old data, new findings

Implanted electrode helps paralyzed monkey clench its forearm muscles

Spock is almost human

Great edition work with very nice synchronization…
For trekkers…

Have a nice weekend.

Physical limits of inference – Theories of almost everything?

There is a review at Nature’s News and Views section by P.-M. Binder about a recent article by David H. Wolpert from NASA Ames Research Center, entitled “Physical limits of inference“. Binder writes:

A provocative contribution to the logic of science extends the theorems of Kurt Gödel and Alan Turing, and bears on thinking about prediction, the standard model of particles, and quantum gravity.

From the abstract of the paper, one reads

We show that physical devices that perform observation, prediction, or recollection share an underlying mathematical structure. We call devices with that structure “inference devices”. We present a set of existence and impossibility results concerning inference devices. These results hold independent of the precise physical laws governing our universe. In a limited sense, the impossibility results establish that Laplace was wrong to claim that even in a classical, non-chaotic universe the future can be unerringly predicted, given sufficient knowledge of the present. Alternatively, these impossibility results can be viewed as a non-quantum-mechanical “uncertainty principle”.

[Yeah, Laplace was wrong even classically, according to my SF novel... ]

and

(…) We informally discuss the philosophical implications of these results, e.g., for whether the universe “is” a computer.

I find it very surprising that this was published in Physica D: Nonlinear Phenomena, and not in a philosophical journal. I have no criticisms against this work in particular (I did not read the paper in full), it is just that it does not seem, from a first impression, a physics paper per se, as much as interesting as it may seem.

Another (somewhat funny, I must admit, but it may be a reflection of my present pessimistic/sarcastic mood) excerpt from Binder’s review is this:

The other limitation is our inability to bring quantum mechanics and gravity into a single theory, although several viable alternative theories are being studied [9]. Quantum electrodynamics, a refinement of quantum mechanics, is defined by just two parameters (the charge and mass of the electron), whereas quantum gravity would require infinitely many parameters, and hence infinite experiments to determine those parameters, making it so far a meaningless theory.

BTW, Ref. [9] above is Wilczek’s book, The Lightness of Being.

Physics Nobel Prize 2008 announced

The prize goes to three Japanese:

Yoichiro Nambu (1/2) “for the discovery of the mechanism of spontaneous broken symmetry in subatomic physics” and to Makoto Kobayashi (1/4) and Toshihide Maskawa (1/4) “for the discovery of the origin of the broken symmetry which predicts the existence of at least three families of quarks in nature”.

It is somewhat foolish, but I find exciting to see Nobel prizes announced. Congratulations!

Edit: Does anyone have a clue why Nicola Cabibbo did not receive the prize along with Kobayashi and Maskawa?

Edit: See also:

César Lattes – Historical Meme

Physics Nobel 2007

Quantum gravity is not what we think!

At least, this is what Penrose says. You can find more about Penrose’s arguments (and other interesting talks) by watching the PIRSA videos of the recent conference “The Clock and the Quantum: Time and Quantum Foundations“.