A good part of basic research in fundamental physics focuses on the definition, the prediction, and the measurement of quantities which put the current theory -the standard model- to the test in the most stringent way possible. The choice of the quantities on which to base our comparisons between theory prediction and measurement is critical: it entails understanding what may make the comparison imprecise (i.e. experimental systematics affecting the measurement) or fruitless (i.e. theoretical assumptions or a bad definition of the quantity to measure).
One clear example, which I used last week in my lessons of Subnuclear Physics to undergraduates in Padova, is the measurement of the W and Z boson cross sections at the Tevatron proton-antiproton collider.
Track your comments!
[x]
When you register, comments on your articles and replies to your comments appear here. Register Now!
Physical Sciences
Measurements matter in global climate affairs. "IBUKI" is the Greenhouse gases Observing SATellite (GOSAT) that has been circling the Earth since January 23, 2009.
IBUKI ('breath' in Japanese) will assist in precise monitoring of the global atmospheric carbon dioxide concentrations when its observation data sent from space are combined with data obtained on land and used with simulation models. Methane is also observed.
Onboard Instruments
For this experiment, two identically thin cylinders which are initially static to the observer are taken. These cylinders are attached with internal mechanical springs that induce a repulsive action between them.
Two experiments are to be conducted.
Two experiments are to be conducted.
The first experiment.
1571 was also interesting. Galileo Galilei was then seven years old. Johannes Kepler was born on December 27. There were two solar eclipses, a total on January 25 and an annular on July 21-22. Four, one partial and three penumbral, lunar eclipses occurred on August 5 and February 10, July 7, and December 31, respectively.
Will the $ 1,000,000 Randi Challenge Prize soon be awarded? The prize, administered by the James Randi Educational Foundation (JREF), is offered to anyone who can prove in scientifically controlled tests some form of paranormal power. So far, Randi's prize has not been claimed, but rumour has it that under supervision of the JREF an elaborate telepathy test is being conducted with shocking results.
A JREF staff member, who wishes to remain anonymous, commented on the ongoing tests with the words “I have never witnessed anything like this, this is deeply disturbing”.
Did someone mention Elvis? This research made the cover of ACS's Journal of Physical Chemistry in color.
An elevator to space? No, this isn't a reprise of Charlie and Chocolate Factory. As I mentioned in a blog back in January, an elevator into space is the end goal - a 100,000 km long tether anchored to the Earth as a "lift into space" for cheaper space missions.
"The yield of muon pairs decreased rapidly from 1 GeV to the kinematic limit of nearly 6 GeV with the exception of a curious shoulder near 3GeV. The measurement of muons was by range as determined by liquid and plastic scintillation counters interspersed with steel shielding. Each angular bin (there were 18) had four range bins, and for two muons this made a total of only 5000 mass bins into which to sort the data. Multiple scattering in the minimum of 10 feet of steel
made finer binning useless. Thus we could only note that "Indeed, in the mass region near 3.5 GeV, the observed spectrum may be reproduced by a composite of a resonance and a steeper continuum." This 1968-1969 experiment was repeated in 1974 by Aubert et al. (1974), with a
made finer binning useless. Thus we could only note that "Indeed, in the mass region near 3.5 GeV, the observed spectrum may be reproduced by a composite of a resonance and a steeper continuum." This 1968-1969 experiment was repeated in 1974 by Aubert et al. (1974), with a
Hello. See the giant structure in 2D and also in 3D. The positions of the galaxies in the newly found structure are shown in red in the second and third images. Other galaxies in "blue" are located in front or behind "the Giant."
To relate to the size of things, consider first the Whirlpool Galaxy for example. This bright galaxy is 23 million light years away and 75,000 light years across.
Credit: NAOJ.
I am presently into the second week of my lessons of Subnuclear Physics for the 2nd year of specialization in Physics, and I have just finished a lesson discussing the current searches for the Higgs boson at the Tevatron collider. Since the course has a focus on experimental techniques, I found it useful today to give as an exercise the determination of an order-of-magnitude estimate of cross section limits that the CDF experiments can set on a 160 GeV Higgs boson, with the data so far analyzed. It is an exercise I worked out by heart during my walk to the Physics Department: this should tell you it is not of overpowering difficulty.
Know Science And Want To Write?
What People Are Saying
- "Great food for thought--this little grad student thanks you! Before I could start thinking about..."
- "Thanks all for the comments!..."
- "Another thing. A flight attendant (prosecution witness) testified that MJ drank wine in soda cans..."
- "Never said he did not have a substance abuse problem. What I said is that media reports right after..."
- "Some other physicists also like differences.Theoretical, conformal, two-dimensional physicists..."
- Scientists visualize how bacteria talk to one another
- Findings show nanomedicine promising for treating spinal cord injuries
- Developmental delay could stem from nicotinic receptor deletion
- Deep creep means milder, more frequent earthquakes along Southern California's San Jacinto fault
- Indiana U. at APHA: Studies about health education for people with ID, stability balls at work
