The Say of the Week: ID take that! January 7, 2009
Posted by dorigo in humor, religion, science.Tags: creationism, ID
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“Why do dogs do the squashiest, most unpleasant turds that hide in the grass and spread themselves in the indentations on the bottom of your shoe, but don’t start smelling until you get indoors and then render the place uninhabitable until you’ve left every window open for a month? Why, why, why?
Come on intelligent design people, the questions you have to answer have barely begun.”
(Mark Steel, What creationists really hate is that we emerged by accident.)
Do not take their advice, they are not known for their brains! January 7, 2009
Posted by dorigo in internet, news, science.Tags: journalists, media, pseudoscience, science reporting
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Sense about Science, the british organization which
respond[s] to the misrepresentation of science and scientific evidence on issues that matter to society, from scares about plastic bottles, fluoride and the MMR vaccine to controversies about genetic modification, stem cell research and radiation [...],
has issued their 2008 report on many dangerous claims held by celebrities about scientific issues, exposing their falsity and the scientific facts that prove it. The claims that the Tom Cruises, the Mariah Careys, the Kelly Osbournes distribute are dangerous not so much for their content, but because of the enormous amplification those claims get by the media, always hunting for anything connected to famous people.
While commendable, the report is a drop in the sea, as it does not address the source of the problem: the pseudo-scientific approach that newspapers and other media deliberately choose to support. It is in fact the responsibility of the journalists if those claims are reported without commentary or the opinion of a scientist. It would take them the effort of a phone call in most instances, but they fear to bore or distract their readers. That is nonsense! Really, the newspapers and magazines would not sell fewer copies if they appended a few lines of healthy, matter-of-fact criticism to the farnetications of the starlet on duty.
My suggestion would be to expose the journalists rather than the celebrities! A well-organized site targeting professional writers and commenters would go a longer way in this fight against the diffusion of pseudo-science, because these people do it for a living. SAS does not seem to be aiming in that direction. Are readers of this blog aware of any such enterprise ? It would get my support.
In any case, the SAS report is interesting. You can download it from this link for an entertaining break. Happy reading!
Some posts you might have missed in 2008 – part II January 6, 2009
Posted by dorigo in physics, science.Tags: anomalous muons, CDF, D0, Higgs boson, LHC, Lubos Motl, new physics, PDF, QCD, Tevatron, top mass, top quark, Z boson
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Here is the second part of the list of useful physics posts I published on this site in 2008. As noted yesterday when I published the list for the first six months of 2008, this list does not include guest posts nor conference reports, which may be valuable but belong to a different place (and are linked from permanent pages above). In reverse chronological order:
December 29: a report on the first measurement of exclusive production of charmonium states in hadron-hadron collisions, by CDF.
December 19: a detailed description of the effects of parton distribution functions on the production of Z bosons at the LHC, and how these effects determine the observed mass of the produced Z bosons. On the same topic, there is a maybe simpler post from November 25th.
December 8: description of a new technique to measure the top quark mass in dileptonic decays by CDF.
November 28: a report on the measurement of extremely rare decays of B hadrons, and their implications.
November 19, November 20, November 20 again , November 21, and November 21 again: a five-post saga on the disagreement between Lubos Motl and yours truly on a detail on the multi-muon analysis by CDF, which becomes a endless diatriba since Lubos won’t listen to my attempts at making his brain work, and insists on his mistake. This leads to a back-and-forth between our blogs and a surprising happy ending when Motl finally apologizes for his mistake. Stuff for expert lubologists, but I could not help adding the above links to this summary. Beware, most of the fun is in the comments threads!
November 8, November 8 again, and November 12: a three-part discussion of the details in the surprising new measurement of anomalous multi-muon production published by CDF (whose summary is here). Warning: I intend to continue this series as I find the time, to complete the detailed description of this potentially groundbreaking study.
October 24: the analysis by which D0 extracts evidence for diboson production using the dilepton plus dijet final state, a difficult, background-ridden signature. The same search, performed by CDF, is reported in detail in a post published on October 13.
September 23: a description of an automated global search for new physics in CDF data, and its intriguing results.
September 19: the discovery of the 
August 27: a report on the D0 measurement of the polarization of Upsilon mesons -states made up by a 
August 21: a detailed discussion of the ingredients necessary to measure with the utmost precision the mass of the W boson at the Tevatron.
August 8: the new CDF measurement of the lifetime of the 
August 7: a discussion of the new cross-section limits on Higgs boson production, and the first exclusion of the 170 GeV mass, by the two Tevatron experiments.
July 18: a search for narrow resonances decaying to muon pairs in CDF data excludes the tentative signal seen by CDF in Run I.
July 10: An important measurement by CDF on the correlated production of pairs of b-quark jets. This measurement is a cornerstone of the observation of anomalous multi-muon events that CDF published at the end of October 2008 (see above).
July 8: a report of a new technique to measure the top quark mass which is very important for the LHC, and the results obtained on CDF data. For a similar technique of relevance to LHC, also check this other CDF measurement.
Ili’s hairdo January 5, 2009
Posted by dorigo in personal.Tags: ilaria, pictures
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Ilaria is very proud of her new look. Check her out:
Some posts you might have missed in 2008 January 5, 2009
Posted by dorigo in cosmology, personal, physics, science.Tags: CDF, CMS, dark matter, Higgs boson, LHC, new physics, particle detectors, physics, standard model, SUSY, top quark, top quark mass
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To start 2009 with a tidy desk, I wish to put some order in the posts about particle physics I wrote in 2008. By collecting a few links here, I save from oblivion the most meaningful of them -or at least I make them just a bit more accessible. In due time, I will update the “physics made easy” page, but that is work for another free day.
The list below collects in reverse chronological order the posts from the first six months of 2008; tomorrow I will complete the list with the second half of the year. The list does not include guest posts nor conference reports, which may be valuable but belong to a different list (and are linked from permanent pages above).
June 17: A description of a general search performed by CDF for events featuring photons and missing transverse energy along with b-quark jets – a signature which may arise from new physics processes.
June 6: This post reports on the observation of the decay of J/Psi mesons to three photons, a rare and beautiful signature found by CLEO-c.
June 4 and June 5 offer a riddle from a simple measurement of the muon lifetime. Readers are given a description of the experimental apparatus, and they have to figure out what they should expect as the result of the experiment.
May 29: A detailed discussion of the search performed by CDF for a MSSM Higgs boson in the two-tau-lepton decay. Since this final state provided a 2.1-sigma excess in 2007, the topic deserved a careful look, which is provided in the post.
May 20: Commented slides of my talk at PPC 2008, on new results from the CDF experiment.
May 17: A description of the search for dimuon decays of the B mesons in CDF, which provides exclusion limits for a chunk of SUSY parameter space.
May 02 : A description of the search for Higgs bosons in the 4-jet final state, which is dear to me because I worked at that signature in the past.
Apr 29: This post describes the method I am working on to correct the measurement of charged track momenta by the CMS detector.
Apr 23, Apr 28, and May 6: This is a lengthy but simple, general discussion of dark matter searches with hadron colliders, based on a seminar I gave to undergraduate students in Padova. In three parts.
Apr 6 and Apr 11: a detailed two-part description of the detectors of electromagnetic and hadronic showers, and the related physics.
Apr 05: a general discussion of the detectors for LHC and the reasons they are built the way they are.
Mar 29: A discussion of the recent Tevatron results on Higgs boson searches, with some considerations on the chances for the consistence of a light Higgs boson with the available data.
Mar 25: A detailed discussion on the possibility that more than three families of elementary fermions exist, and a description of the latest search by CDF for a fourth-generation quark.
Mar 17: A discussion of the excess of events featuring leptons of the same electric charge, seen by CDF and evidenced by a global search for new physics. Can be read alone or in combination with the former post on the same subject.
Mar 10: This is a discussion of the many measurements obtained by CDF and D0 on the top-quark mass, and their combination, which involves a few subtleties.
Mar 5: This is a discussion of the CDMS dark matter search results, and the implications for Supersymmetry and its parameter space.
Feb 19: This is a divulgative description of the ways by which the proton structure can be studied in hadron collisions, studying the parton distribution functions and how these affect the scattering measurements in proton-antiproton collisions.
Feb 13: A discussion of luminosity, cross sections, and rate of collisions at the LHC, with some easy calculations of the rate of multiple hard interactions.
Jan 31: A summary of the enlightening review talk on the standard model that Guido Altarelli gave in Perugia at a meeting of the italian LHC community.
Jan 13: commented slides of the paper seminar gave by Julien Donini on the measurement of the b-jet energy scale and the 
Jan 4: An account of the CDF search for Randall-Sundrum gravitons in the 
What is a glueball ? January 4, 2009
Posted by dorigo in Blogroll, physics, science.Tags: glueballs, gluons, lattice QCD, QCD
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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!
Watch the Quadrantid meteors tonight! January 3, 2009
Posted by dorigo in astronomy, personal, science.Tags: meteor showers, quadrantids
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Tonight the Earth will cross the core of a filament of debris orbiting our Sun since the passage of a comet in the year 1490. This will give rise to a spectacular shower of meteors, the Quadrantids.
I observed this shower in 2002 and 2004. In particular, I vividly remember the night of January 4th, 2004: exactly five years ago, I witnessed a beautiful peak of this meteor stream. Quadrantids are not so well known as the more famous Perseids or Leonids, but they can provide quite sizable rates during the first nights of January.
Tonight I am unable to repeat the bold feat of 2004: I feel tired after a day on the snow, and the temperature outside is -15 degrees! However, if you have a chance, please have a look at the sky. Quadrantids flow out of a point of sky between Ursa Mayor and Bootes, high up in the northern sky in the second half of the night. You need not observe in that direction: meteors will streak from that point in all directions.
Five years ago I drove to Passo S.Antonio, not far from Padola, where I am right now on vacation. The night then was bitterly cold, -11 to -14 degrees, but I had dressed up with several layers of warm clothing. Nevertheless, in order to stay out watching the stars I had to make frequent runs back and forth. I managed to observe for four hours!
I took notes of the time and magnitude of all the quadrantid meteors I saw during the four hours of observation. In the end, there were 144 of them (plus 13 non-quadrantids)! The peak was, as expected, in the hours before dawn, when I saw 40 tracks in a 15′ period before 6AM. My notes also show that at 5.48AM I observed FOUR simultaneous meteors, all in Virgo, and separated about 10 degrees. Two of visual magnitude 3.0, and two of magnitude 4.0. A spectacular event!
Below I report a few graphs I made after data analysis. The first shows the Zenith Hourly Rate (ZHR), the meteor rate per hour corrected for the altitude of the radiant, the light pollution, and other factors. As you can see, the ZHR soared to about 200 just before dawn on January 4th, 2004.
The fit is a gaussian distribution (other curves could provide just as good an interpretation of the distribution of ZHR values), which peaks at 5AM UT, with a rate of exactly 200. Note that the point between 3.75 and 4.00 is not zero: it is missing, since I took a break!
The second graph shows the distribution of visual magnitude of the 144 quadrantid tracks, a distribution which one needs to fit in order to find a coefficient R, the population index (basically an exponential slope), used in the computation of the ZHR. If the shower has many bright meteors, R is small, and the ZHR receives a smaller correction if the sky darkness is not perfect (fewer faint tracks fall unseen). My fit obtains 
The distribution of visual magnitudes falls for values above 6.0, since the sky was not free from light pollution, and the faintest meteors I could detect were of magnitude 5.0: only three of them, seen just because I was looking exactly where they fell. The human eye is unable to detect faint signals with peripheric vision, and that is the reason of the dampening of the curve for values above 4.0.
I hope some of you may spend some time out tonight, and let me know how many Quadrantids could be seen!
Update: upon checking a few sources, I found out that the peak this year was last night! This night the rate should be in the few tens per hour… I feel relieved after all! In fact, while I am already in bed with my laptop as I write these lines, until I discovered that the peak has already happened a part of me wanted to pull my body out, dress up like a total freak, and drive to a remote place!
Gaza strike “defensive” for UE presidency January 3, 2009
Posted by dorigo in news, politics.comments closed
After a long discussion with anonymous commenters in a thread developed here yesterday, I have to record the latest declaration by the Czech spokesperson Jiri Potuznik, from the UE presidency. He claims that the Israeli offensive in the Gaza strip is “a defensive and not an offensive action“.
I wonder whether the Czech foreign minister Karel Schwarzenberg, who will lead the UE delegates in Israel tomorrow, is going to promise humanitarian support to Israel, in such a delicate defensive moment.
Bitter jokes aside, I acknowledge that I belong to a minority. Feeling closer by culture to Israel than to palestine, I am asking a lot to Israel -finding a non-violent way to react to the threats and attacks- and nothing to Hamas. To me, these military incursions by the strongest army in the world into a battered strip of land are a barbarian act. I of course would have trouble finding pacate words to describe the horror of random rocket attacks to cities and suicide bombings of buses and night clubs.
I am a Bright! January 2, 2009
Posted by dorigo in Blogroll, internet, personal, religion.Tags: Brights, religion
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Just joined the Brights’ net! You might want to check the website, I bet a large fraction of visitors here are Brights without knowing it…
Here is what it means to be a Bright:
- A bright is a person who has a naturalistic worldview
- A bright’s worldview is free of supernatural and mystical elements
- The ethics and actions of a bright are based on a naturalistic worldview
And kudos to David Orban who pointed at the site in his blog.
Stop the bombs! January 2, 2009
Posted by dorigo in history, news, politics.Tags: gaza, hamas, livni, middle east, war
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It is quite sad for me to see a country built on the ashes of millions of jews, victims of the nazis during WWII, show for the umpteenth time their leaders and soldiers are not altogether different from their grandparents’ executioners. We are all human, and that means we are all beasts. Israel feels threatened by the constant threat of palestinian attacks -not a big threat, to be honest: the wiping out of Israel off the middle east map is an oversold story which has lost all its meaning since the seventies- and decides unilaterally to unleash an attack on a strip of land so thin that planes would have trouble landing along its shorter side.
And hundreds die. More than 400 so far, plus 2000 wounded, most of them civilians of course. The acclaimed killing by israeli bombs of a Hamas leader, Nizar Rayyan, cost the life of his wives and 10 of his 12 children. Rayyan was no doubt an extremist and a fomenter of suicide attacks, but I ask your forgiveness if I can see no difference between the bombs that killed him and his family and those he tried to explode in israeli soil. Terrorist is Hamas, and terrorist is Tzipi Livni and her government.
What is striking to me is how plain it is to see, from a distance, that these bombs are only a political tool for power, and that they will but cause more suffering to the same israeli people that dropped them. Does Livni think that killing a few Hamas leaders and a few thousand civilians will cool down the minds of the arabs ? No, she does not. But she feels more powerful today.
