5 ms·

Quarks Know Their Left From Their Right

43 points by engassa 13y ago

kartikkumar 13y ago
Awesome result. I think it's vitally important to acknowledge achievements that happen in parallel with research at the LHC because otherwise we're going to miss a lot of very neat results. I don't know enough about particle physics to be able to comment on the techniques involved unfortunately, but I love reading about the progress that's being made. For someone that Wikipedia's a lot of this stuff, does someone know if this type of spin asymmetry is in any sense related to CP violation? [1] As soon as I read the article I thought of CP violation and I'm assuming this is basically the "P" violation. Finally, reading this article actually triggered a totally different question: "Using the electron accelerator at Thomas Jefferson National Accelerator Facility in Newport News, Virginia, the researchers shined 170 billion electrons on a target of liquid deuterium over 2 months in 2009." Shined or shone? Turns out to be quite the discussion topic (e.g., [2][3][4])! [1] http://en.wikipedia.org/wiki/CP_violation http://en.wikipedia.org/wiki/CP_violation [2] http://public.wsu.edu/~brians/errors/shined.html http://public.wsu.edu/~brians/errors/shined.html [3] http://grammarist.com/usage/shined-shone/ http://grammarist.com/usage/shined-shone/ [4] http://motivatedgrammar.wordpress.com/2010/10/18/has-the-sun-shined-or-shone/ http://motivatedgrammar.wordpress.com/2010/10/18/has-the-sun...
- alxprc 13y ago
  As it says in the article, this is the discovery of parity, P, violation in a system where it's not been seen before. In a "nice" universe, one might expect mirror images to behave the same, but here they've discovered that interactions between electrons and quarks are different depending on the spin of the electron. So, it's related to CP violation in the sense that it something "violates CP symmetry" if it's behaviour changes when you flip the charge and the parity of the system simultaneous. Here, they only flip the parity.
milliams 13y ago
For a science magazine, this article does a terrible job of talking about spin. Saying "spinning as it zips along—to the right like a football thrown by a right-handed quarterback or the left like a pigskin thrown by a lefty" is immensely confusing to anyone who actually wants to understand what's going on.
- josteink 13y ago
  I've seen this trend several places recently. People are trying to dumb down science so it can be "understandable", often by using sport-analogies. It doesn't help that these dumbed down sport-analogies often feature American sports seldom found in other countries. The net effect is that if I was in need of a explanation, I'm still confused and all of a sudden annoyed at footballers too.
  - adobriyan 13y ago
    Spinning ball analogy is very common in school or basic uni. I think it is spinning ball 100% of the time.
    - TrainedMonkey 13y ago
      We do not actually know if it physically is spinning. What we know that it behaves like it is spinning.
- adobriyan 13y ago
  The problem with science magazines is that if you dumb down paper enough for general public to "understand" it there is basically nothing left. Article doesn't even try to describe what this $2 C_{2 u} − C_{2 d}$ coupling is all about. If you're trying to follow High Energy Physics, your best choice is to follow abstracts in ArXiV (which in turn requires _some_ knowledge and education :-(.
- jpeterson 13y ago
  Can someone explain what's wrong with the spinning ball analogy? From my understanding, it's a pretty good first approximation of the physical interpretation of particle spin.
gnaritas 13y ago
Quarks don't know anything and they don't spin like a football, bad science reporting is bad science reporting.

43 points by engassa 13y ago

Awesome result. I think it's vitally important to acknowledge achievements that happen in parallel with research at the LHC because otherwise we're going to miss a lot of very neat results. I don't know enough about particle physics to be able to comment on the techniques involved unfortunately, but I love reading about the progress that's being made. For someone that Wikipedia's a lot of this stuff, does someone know if this type of spin asymmetry is in any sense related to CP violation? [1] As soon as I read the article I thought of CP violation and I'm assuming this is basically the "P" violation. Finally, reading this article actually triggered a totally different question: "Using the electron accelerator at Thomas Jefferson National Accelerator Facility in Newport News, Virginia, the researchers shined 170 billion electrons on a target of liquid deuterium over 2 months in 2009." Shined or shone? Turns out to be quite the discussion topic (e.g., [2][3][4])! [1] http://en.wikipedia.org/wiki/CP_violation http://en.wikipedia.org/wiki/CP_violation [2] http://public.wsu.edu/~brians/errors/shined.html http://public.wsu.edu/~brians/errors/shined.html [3] http://grammarist.com/usage/shined-shone/ http://grammarist.com/usage/shined-shone/ [4] http://motivatedgrammar.wordpress.com/2010/10/18/has-the-sun-shined-or-shone/ http://motivatedgrammar.wordpress.com/2010/10/18/has-the-sun...

alxprc 13y ago
As it says in the article, this is the discovery of parity, P, violation in a system where it's not been seen before. In a "nice" universe, one might expect mirror images to behave the same, but here they've discovered that interactions between electrons and quarks are different depending on the spin of the electron. So, it's related to CP violation in the sense that it something "violates CP symmetry" if it's behaviour changes when you flip the charge and the parity of the system simultaneous. Here, they only flip the parity.

milliams 13y ago

For a science magazine, this article does a terrible job of talking about spin. Saying "spinning as it zips along—to the right like a football thrown by a right-handed quarterback or the left like a pigskin thrown by a lefty" is immensely confusing to anyone who actually wants to understand what's going on.

josteink 13y ago
I've seen this trend several places recently. People are trying to dumb down science so it can be "understandable", often by using sport-analogies. It doesn't help that these dumbed down sport-analogies often feature American sports seldom found in other countries. The net effect is that if I was in need of a explanation, I'm still confused and all of a sudden annoyed at footballers too.
- adobriyan 13y ago
  Spinning ball analogy is very common in school or basic uni. I think it is spinning ball 100% of the time.
  - TrainedMonkey 13y ago
    We do not actually know if it physically is spinning. What we know that it behaves like it is spinning.
adobriyan 13y ago
The problem with science magazines is that if you dumb down paper enough for general public to "understand" it there is basically nothing left. Article doesn't even try to describe what this $2 C_{2 u} − C_{2 d}$ coupling is all about. If you're trying to follow High Energy Physics, your best choice is to follow abstracts in ArXiV (which in turn requires _some_ knowledge and education :-(.
jpeterson 13y ago
Can someone explain what's wrong with the spinning ball analogy? From my understanding, it's a pretty good first approximation of the physical interpretation of particle spin.

gnaritas 13y ago

Quarks don't know anything and they don't spin like a football, bad science reporting is bad science reporting.