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?
- Can A New Rule Trigger A Second EU Referendum? Petition Signatures Over 8% Of Total Votes Cast
- How A Former Naturopath Can Help Unravel The Trickery of Alternative Medicine
- Beneficial Bacteria May Protect Breasts From Cancer
- Better Brains With Beer
- Finding All-Hadronic Top - Again
- Cross Talk Between Hormone Receptors Has Unexpected Effects
- Small Brain -- Astounding Performance
- "I see the actions as no different than the group that promoted the California Bond issue for Stem..."
- "I don't understand the problem. The drug side effects are a true telling of what researchers have..."
- "Seeing oneself foremost as a citizen of the country founded by one's ancestors is hardly a problem..."
- "If Puerto Rico had a $2 trillion economy, 5% unemployment, and the ability to lose $10 billion..."
- "Crystal clear writing, as usual. I thought I may have detected the same writing style in amongst..."
- Chemistry Can Help Roast the Perfect Coffee Bean
- What Happens To A Soccer Player’s Brain After Missing A Penalty Kick
- It’s Back to Shots for Flu Prevention
- ACSH Applauds Media Awareness of the Fentanyl Crisis
- Counting Bites Examined, to Help Decrease Food Intake
- The Safe And Unsafe Nutty Treats For Your Pup