The turnaround of the three physics questions I offered a few days ago, to stimulate your neurons and extract you from the chocolate and alcohol flood caused by the usual string of Christmas parties and dinners, was rather scarce. Despite that, I wish to repeat the offer today, making some adjustments to reach a wider public. The questions I offer here are easier but still not accessible to everybody. However, my plans are that at least the answers I will give in a couple of days will be understandable. Further, anyone can try the bonus question I ask at the bottom of this piece...
So below are three more questions on experimental high-energy physics, a bit more accessible than the previous ones. Please try them and report your answers below. The time you spend on the test will not be wasted!
1) The LHC experiments will search for Z bosons in their early 2010 data. The Z decay to muon pairs, in particular, provides a means to verify the correct alignment of tracking detectors and the precise modeling of the magnetic field inside the solenoid, which bends charged tracks traversing its volume.
If the signal cross section equals 50 nanobarns, and only three decays in a hundred produce muon pairs, calculate the integrated luminosity required to identify 100 candidates, assuming that the efficiency with which a muon is detected is 70%.
Hint: you will need to use the formula , and all the information provided above.
2) In the decay of stopped muons, , the produced electron is observed to have an energy spectrum peaking close to the maximum allowed value. What is this maximum value, and what causes the preferential decay to energetic electrons ?
Hint: you might find inspiration in the answer to the first question I posted on Dec. 26th.
3) The decay to an electron-neutrino pair of the W boson occurs one-ninth of the time, because the W may also decay to the other lepton pairs and to light quarks, and the universality of charged weak currents guarantees an equal treatment of all fermion pairs. The question is: if the W boson had a mass of 300 GeV, what would the rate of electron-neutrino decays ?
Hint: the top quark would play a role...
Bonus question: What do you get if you put together three sexy red quarks ?
Answers in a couple of days... Take your thinking hat and start working now!
- PHYSICAL SCIENCES
- EARTH SCIENCES
- LIFE SCIENCES
- SOCIAL SCIENCES
Subscribe to the newsletter
Stay in touch with the scientific world!
Know Science And Want To Write?
- Will NASA's Sample Return Answer Mars Life Questions?
- Gaming on Windows 10 Build 10122, The Good, The Bad and The Malfunctioning. (UPDATE 10130 same issues)
- San Andreas, The Movie: 5 Geology Facts Versus Fictions
- The Real Ghost Of Kubrick's Version Of "The Shining" - Franz Kafka
- Gamify Your Life: Social Media Metrics Let You Get A Quantified Digital Version Of Yourself
- Amphetamine is Awesome
- Will Female Viagra Be An FDA Boner?
- "In a 23 page response, LaCour says the inability to reproduce his finding was due to a failure..."
- "Many years ago, when I worked in the dental x-ray field, we had to deal with what was called 'quantum..."
- "From near the end of the 19th century:quoted from:Gadflies and Geniuses in the History of Gas Theory..."
- "I agree, that post is probably spam but probably not automated spam. Nice article. I am debating..."
- "'Delusional Parasitosis' has become yet another 'catch-all' in the WHDITYMBARN (we haven't diagnosed..."
- FDA Addresses Concerns on Approval of Drugs to Treat Chronic Hepatitis C
- Wearing high-heeled shoes may cause ankle muscle imbalance and injury
- Yeast protein network could provide insights into human obesity
- Warmer climates may increase pesticides' toxicity in fish
- Soil erosion contributes significantly to global carbon emissions