For each of the previous 5 times that I went to the Los Alamos
cafeteria, I bought a 20 oz. bottle of Coke, all of which had a
winning cap which allowed me get a free 1 L bottle of Coke. The
probability of winning in any one bottle is 1/6 and since I won 5
times in a row... I just pulled off something that has a chance of
1/7776! I won't even try to calculate how far this is from norm in
terms of sigma, the favorite term that physicists like to use to
determine the likelihood of a signal.
So what does this have to do with pentaquarks, that exotic state of 5 quarks. A few days ago I attended a seminar by Ed Hartouni from Lawrence Livermore National Lab, in which he described some analysis he did searching for a pentaquark signal with a fixed target p+p experiment at Fermilab. They didn't find anything. But there are several experiments which show pentaquark results: effects of several sigmas even and then there are several experiments which published results indicating no pentaquarks. What does this mean in terms of statistical significance? This brings me back to the incident of 5 consecutive free Coca Cola wins for me. If I naively assume that each of these wins is independent, then I get the absurd result of 1/7776. However if I assume that these events correlated, then I get a much more reasonable probability of 1/6. Obviously we need to be more careful when we quote results in terms of sigma as there might be unforseen correlations. It also reminds of a news headline I read "50% of scientific papers are wrong". This applied to medicine but sometimes I wonder it applys to physics. For instance with regard to pentaquarks, I know that my experiment PHENIX had "Seen" a pentaquark signal last year. But fortunately before the results became official, a mistake was found: a miscalibration in the timing of the Electromagnetic Calorimeters lead to a false signal. And yet this finding was never published... In some ways there is more to learn from these mistakes than another "discovery". I wish that some of these negative finding papers were also published so that some other experimental collaboration does not make the same mistake.
So what does this have to do with pentaquarks, that exotic state of 5 quarks. A few days ago I attended a seminar by Ed Hartouni from Lawrence Livermore National Lab, in which he described some analysis he did searching for a pentaquark signal with a fixed target p+p experiment at Fermilab. They didn't find anything. But there are several experiments which show pentaquark results: effects of several sigmas even and then there are several experiments which published results indicating no pentaquarks. What does this mean in terms of statistical significance? This brings me back to the incident of 5 consecutive free Coca Cola wins for me. If I naively assume that each of these wins is independent, then I get the absurd result of 1/7776. However if I assume that these events correlated, then I get a much more reasonable probability of 1/6. Obviously we need to be more careful when we quote results in terms of sigma as there might be unforseen correlations. It also reminds of a news headline I read "50% of scientific papers are wrong". This applied to medicine but sometimes I wonder it applys to physics. For instance with regard to pentaquarks, I know that my experiment PHENIX had "Seen" a pentaquark signal last year. But fortunately before the results became official, a mistake was found: a miscalibration in the timing of the Electromagnetic Calorimeters lead to a false signal. And yet this finding was never published... In some ways there is more to learn from these mistakes than another "discovery". I wish that some of these negative finding papers were also published so that some other experimental collaboration does not make the same mistake.
wrong scientific papers do bring the truth or rather the nature of methods used. sometimes this methods when applied to different research works better. its scary to think that in a dynamic universe, all the norms are constantly changing, andthat what we discover today might not last tommorow.
Posted by: Gp | September 19, 2005 at 12:35 PM
he's the leader... (RBR-443)
Posted by: m.visaya | September 22, 2005 at 08:10 PM
here's a possible explanation: suppose we assert p if -3*((1+((cos t)/3))^2) not zero. what does one win everytime? to keep rolling...
(KCO-596)
Posted by: m.visaya | September 28, 2005 at 10:58 AM
Love is two people sipping Coca Cola from the same straw on a warm sunny day.
Posted by: Lamar Cole | October 12, 2005 at 01:17 PM
nice fence but clearly they ordered another MORASS!
Posted by: m.visaya | October 28, 2005 at 01:19 PM