Take the 2-minute tour ×
Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It's 100% free, no registration required.

I think there is some theoretical uncertainty whether high-energy collisions can violate B. It is known that at high temperature (higher than the Higgs scale) you violate B by SU(2) instantons. But in a situation where you have a very energetic 2-particle collision at arbitrarily high energy, I am not sure if there is a non-negligible probability of producing a Baryon violating configuration. I don't know of any calculation of B violation expected in accelerators, although there might be an argument that it should be very close to zero, because of the non-thermalizing nature of 2-particle collisions.

Can you detect standard model B violation in colliders? Does LHC look for rare B violating events, or would such rare events be indistinguishable from a proton or neutron escaping undetected?

share|improve this question
    
arxiv.org/abs/1107.3805 possibly? I say "possibly" because I understood not a word of the paper beyond the title :-) –  John Rennie Jul 9 '12 at 17:46
add comment

1 Answer

How about this:

Recently there has been much interest in the use of single-jet mass and jet substructure to identify boosted particles decaying hadronically at the LHC. We develop these ideas to address the challenging case of a neutralino decaying to three quarks in models with baryonic violation of R parity. These decays have previously been found to be swamped by QCD backgrounds. We demonstrate for the first time that such a decay might be observed directly at the LHC with high significance, by exploiting characteristics of the scales at which its composite jet breaks up into subjets.

share|improve this answer
    
Can the detector notice very small nonperturbative B violation? Are there rare events where you don't notice some B escaping from the detector which would make a background too large to notice real B violation? –  Ron Maimon Jul 10 '12 at 19:45
    
It will all depend on the crossections of the rare processes. It is hard to do accuracy physics in a hadron collider. That is why the ILC is pushed. One can find constrained processes in the much cleaner environment. –  anna v Jul 11 '12 at 3:45
    
Assuming a small visible cross section, can you tell if, let's say, 10 events out of 100,000,000 violate B? Or are there 10,000 events where neutrons or protons escape undetected along the beam-line direction, so that these events are lost in the noise? Even in ILC there might be a problem of loss along the beam line, so that B violation might be hard to test, or there might be a way to tell if B is escaping along the beam line, I don't know. That's why I'm asking. The cross sections are going to be small for sure, but I don't know a trustworthy calculation of SM B violation at all energies. –  Ron Maimon Jul 11 '12 at 5:50
    
There will always be incomplete events also because both the incoming are three on three at least, and the outgoing particles have a good probability to get mixed up with the spectator debris. That is why monte carlos are crucial. The incomplete events in the LHC are orders of magnitude more than they will be in the ILC because of the enormous QCD background. At the ILC in principle one could have 4 constraint and 1 constrained events, individual events with no missing energy, or the missing energy and mass known, and where the masses of the particles involved are known. –  anna v Jul 11 '12 at 6:29
    
in this physics expected report of the ILC cdsweb.cern.ch/record/1061261/files/CERN-2007-006_v2.pdf , a lot is expected. I am not able to give you detailed estimates for 10 events in 100.000.000, but I can say that the LHC is a discovery machine and not able to go into details. –  anna v Jul 11 '12 at 6:30
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.