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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”
  2. you go to pdg.lbl.gov and download the Z boson table
  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.


1. Superdog - February 26, 2009

A) 1, then switching to 2, as wikipedia doesn’t have the full listing…
B) I am on pdg already 🙂 — Anyways, I would take the (1, c^2 is 1…)
C) ….
D) 6
E) 2 + 3
F) 1->3->4->2
G) 2+3
H) (honestly) 3
I) None of the above – his choice of being logged in – maybe I would add my identity to his authorized keys … just in case…
K) If it was my code, 2 – but most probably 3… 😛

2. Reperio - February 26, 2009

It is funny! There are my answers:
A) 2 (obviously)
B) 3 (by convention)
C) 2
D) 2 (since its impossible)
E) 3
F) 1 (as a good programmer)
G) 2
H) 4
I) 2
J) 1!
K) 1 (obviously)
Do I qualify? 🙂

3. GR - February 26, 2009

Hahaha. Here is my profile, as an undergraduate nowhere near HEP.

A) 3
B) 6
C) 3 (well I probably shouldn’t have slept through that lecture)
D) 6. Although “all of the above except 1” is above “all of the above except 2”, so that’s equivalent to answering 3…
E) 2. Definitely not 1. Unless the safety guy is there, in which case you turn around quickly so he doesn’t see you don’t have a mask and left your badge at home.
F) 4. Not like I wasn’t going to do that anyways.
G) 2
H) 4
I) 1. Why haven’t I thought of that before?
J) 1. More higgs = more funding = more money to spend on booze
K)1. But really, 3.

4. Amos - February 26, 2009

A) 4
B) 5
C) 3
D) 2
E) 3
F) 4
G) 3
H) 4
I) 5
J) 3
K) 3

So how’d I do? Do I get the job? How much does it pay anyway?

5. Marcos - February 26, 2009

Really cool post, this is my take:
A 3
B 6 (I come from the engineering world!)
C Higgs decay? wasn’t it stable just like the muon? 🙂 I really don’t know how it may decay into two pairs.
D 5, it came from an alien hadron collider
E 2, the HV supply is for me!
F 4, although it would be tea instead of coffee
G 2
H 3
I 5
J 3, it’s always a bug in the code!
K 3, same as before

6. Gina - February 26, 2009

A. 3
B. 5
C. 4
D. 6
E. 1
F. 4
G. 3
H. 4
I. 4
J. 3
K. 1

hopefully i do not look too foolish with my answers….i didnt cheat and it will be obvious!!! haha.

7. carlbrannen - February 26, 2009

Very funny, A2,B5,C2,D4,E1,F1,G3,H2,I5,J4,K3

8. carlbrannen - February 26, 2009

OOps, I meant A3 of course.

9. Kea - February 26, 2009

I have a quibble with D. Carl beat me to the right answer, namely 4, but the question is worded so that 4 is the only possible answer! LOL. One cannot have 5 or 6, because 5 would have to say, ‘all the above except 1 and 4’.

10. Kea - February 26, 2009

OK, so my honest, boring, and maybe not completely serious, answers are:
A3, B1, C2, D4, E3, F3, G1, H4, I2, J4, K2

11. Alberto - February 26, 2009

A3 B6 C4 D4 E3 F3 G3 H4 I1 J3 K1

12. C. - February 27, 2009

T., your traps for people who actually think like _theoretical_ hephysicists are a bunch of fun… and efficient they are, so I will not provide answers lest I expose myself too blatantly! 😉

13. Marco - February 27, 2009

A) 3 (but 4 was really tempting!)
B) 6 (just because 3 has that annoying /c^2)
C) 2 and 3, contributing in different ratios
D) 5
E) 3
F) 1 and 4, according to the day mood
G) 2, then 3 a couple of days later
H) 4
I) 4
J) 1. (b-jets?). No, wait! I just got an email from Savannah: it’s 3 😦
K) 2 (3 was again tempting, but I guess I want to believe 🙂 )

14. Haryo - February 27, 2009

A2 although I would rather use a #define, instead of a magic number.

15. NIcola P - February 27, 2009

a 4
b 6
c 2 (not sure….)
d 6
e 2
f 4 (just because I already know that 1, 2, and 3 do not work…)
g 2
h 4
i 4 (obviously!… and then answer 5: perhaps someone did 4 to me)
j 3
k 3 (just for coherence with j)

16. Astronomy Link List - February 27, 2009

This article has been added to the Astronomy Link List.

17. Emme - February 27, 2009

a 1
b 6
c 2
d 3
e 2
f 1
g 2
h 4
i 5
j 4
k 3

will you release some statistics?

18. Pasquale - February 27, 2009

Ok let’s try:

19. Andrea Giammanco - February 27, 2009

E3 (E2 only during dark nights)
F3, then 4, then 2, then 1, then I mail to a mailing list, begging for help
G1+2, although 3 is the common practice
H3, then 4
I4 unless he is the boss

20. mmfiore - February 27, 2009

There is a new Theory of Everything Breakthrough. It exposes the flaws in both Quantum Theory and String Theory. Please see: Theory of Super Relativity at Super Relativity Einstein was right!

21. Xisy - February 27, 2009

A 4 and live in peace
B 3 (or better, ~106 MeV without c^2)
C 2
D 5 but the most important thing is 2
E 2
F 3 (it works most of the times)
G 2
H 4
I 5 (actually, i never log off)
J 3 (matter of probability)
K 3

22. davide - February 27, 2009

nice! hoping to be a real HEphysicist

23. delo - February 28, 2009

here it is mine!
f3 -> 1 -> 2

24. changcho - March 1, 2009

NIce! A little late, but…

25. Aeradan - March 10, 2009


26. Link list – 27th February 2009 | Astronomy Link List - April 6, 2009

[…] Think like an experimental particle physicist! A Quantum Diaries Survivor Take this short quiz to see if you can think like a particle physicist. The answers will be published on the site in a couple of weeks. […]

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