## Think as an experimental particle physicist: results!February 27, 2009

Posted by dorigo in games, humor, physics, science.
Tags: , ,

I know you are impatient, and the weekend is coming, so while I still hope more of you will leave their results in the comments thread, I give below the key to compute the score of the two-part test I offered in the two previous posts. Each answer has from zero to three of the following symbols: E,T,S,C,D. Just sum each category for now:

## Think like an experimental particle physicist!February 26, 2009

Posted by dorigo in games, humor, physics, science.
Tags: ,

In my ongoing effort to convince my readers that experimental high-energy physics is easy and fun, and to make it more appealing to everybody, I am presenting you with a small test, which should measure your ability to think as an experimental particle physicist. These questions  should be enough to sketch your profile as a HEP worker. You are invited to use five minutes of your time to give your answers in the comments thread below. I will provide results in a couple of days.

• A) You need to insert in your analysis code the width of the Z boson. What do you do ?
1. you google “Z boson width”
3. you dig under a pile of preprints for your copy of the PDG booklet
4. you write “=1.0; // REVISE: Z boson width!!! ” and leave it to a better day
• B) What is the muon mass ?
1. 0.105658367 GeV
2. 0.105658367 GeV/c^2, silly you
3. 105.658367 MeV/c^2
4. 0.1134289256 u
5. “sqrt(0.01116369);” which is a number you retrieved from an old piece of code
6. about 100 MeV, give or take a few
• C) How does the Higgs boson decay to a pair of photons ?
1. by first splitting into a pair of top quarks
2. by first splitting into a fermion loop
3. by first splitting into a pair of W bosons
4. it cannot, the Higgs is not electrically charged
• D) A primary cosmic ray with an energy of 10^17 eV hits the atmosphere. It is determined to be a neutron.
1. it must come from inside our galaxy
2. it is a Nobel prize winning discovery
3. it produces a shower like a proton would
4. all of the above
5. all of the above except 1.
6. all of the above except 2.
• E) A detector is being decommissioned and is being taken apart at a facility near your office.
1. you wear a surgical mask when you walk by -activated powder might be dangerous
2. you drop by and try to scavenge a gadget or two
3. you mail the ex-spokesperson to ask for those yellowed scintillator planes
• F) The code won’t compile…
1. you check the error messages carefully
2. you try it on a different account
3. you hit the “save” button on your editor again and retry
4. you go to the coffee machine and ponder
• G) You are scheduled to talk at a conference, on a topic that is not your own
1. you start reading material one month before
2. you start looking for slides on the same topic a week before
3. you email the authors of the relevant analyses for help four days before
• H) You are on day shift at your experiment next October. What is your main worry right now ?
1. Get on par with the latest safety procedures and make sure your training has not expired
2. Find a substitute for that week for your course of the first semester
3. Find the cheapest flight early on
4. Look for entertainment options for all those evenings
• I) You walk by a colleague’s desk in the evening and find out he’s not logged off his account.
1. you use his email to send himself a reminder
2. you log him off
3. you notify the sys admin
4. you open his mozilla browser to a porn web page
5. you go back to your own desk, remembering you did not log off either
• J) A histogram of the invariant mass of jet pairs  in events containing just two energetic jets shows a compelling peak at 120 GeV.
1. It’s the higgs!
2. It is a statistical fluctuation
3. It is a bug in your code
4. This was a sample of Z boson decays to electron-positron pairs, and those are electrons corrected as if they were jets
• K) What does a significance of three sigma mean ? Four sigma ? Five sigma ?
1. something not so rare; something quite rare; something exceptionally rare.
2. evidence of some new phenomenon; strong evidence of same; observation of new physics!
3. evidence of something fishy;  a bug in the code; a horrible bug in the code.