Pion Definition and 120 Threads

Homework Statement The question is from "Advanced Physics" by Adams and Allday. It is from section 9 "The Physics of Particles", "Practice Exam Questions". It is question 10. The level of this study is between school and University. I am uncertain about the answer to part c, ii (3rd...

Homework Statement What is the speed of a pion if its average lifetime is measured to be 4.91E-8s? At rest, its average lifetime is 2.60E-6s. What is the particle's lifetime at rest? Homework Equations \Delta t = \Delta t0 / \sqrt{1-(v2/c2} The Attempt at a Solution I don't...

Hello! I was just wondering something... Why is it that a negative pion always decays into a muon and antimuon neutrino? Why not an electron and antielectron neutrino? (and the same for a positive pion) Any answers would be grately appreciated :-) Samantha

How is it that \pi\^{\pm} have charges \pm e and \pi\^{0} has a charge of 0? The \pi\^{+} has one up quark and an anti-down quark, which doesn't add up to zero (same deal goes for \pi\^{-}, and the \pi\^{0} has a linear combination that doesn't seem to add up to zero. Where have I gone wrong?

Problem: A group of 'pi' mesons (pions) is observed traveling at speed 0.8c in a particle physics laboratory. (a) What is the factor 'gamma' for the pions? (b) If the pions' proper half-life is 1.8x10^-8 s, what is their half-life as observed in the lab frame? (c) If there were initially...

I have studied that the hadronic matrix element of pion decay (Pi+->mu+ anti muon neutrino) is given as <0|ubar gamma[mu](1-gamma[5])d|pion>. The vector current does not seem to contribute, because it cannot connect a state of unnatural parity to hadronic vacuum. Only the axial and...

The positive W boson decays to a anti-muon and a muon neutrino, it should be a weak interaction. And the positive Pion can decays to a anti-muon and a muon neutrino, too. But the lifetimes of them are totally different, so why? I know the positive Pion is composed of two quarks, but could you...

Is it allowed? such as a electron neutrino and an electron anti-neutrino. And why? Now, I am confused... Thanks.

Hello, I understand that the non-zero (or non-small) rate for \pi^0 \rightarrow \gamma\gamma was historically a big motivation for the non-conservation of the axial current. I've been trying to work on problem IV.7.2 (p. 252) in Zee which asks to show that this amplitude vanishes if \partial_\mu...

Hello! I have to hand in this coursework tomorrow and I just wanted to check I had done it correctly so if someone could have a look I'd be really grateful... It's quite long... Homework Statement A negatively charged pion \pi^{-} has mass m=140MeV/c^{2} and lifetime 2.6 x 10^{-8}s. a)...

Hello. I've been having a hard time finding information about the following reaction: e^{-}+n\rightarrowe^{-}+p^{+}+\pi^{-} I hope you could give me some information about it. I'm interested in energies for the incident e^{-} above 200MeV. I think it has to do something with...

1. The statement, all variables and given/known data I am studying the decay of the \eta-particle. Povh et Al, 'Particles and nuclei' say that a decay into 3 pions is not possible via the strong interaction. "For reasons of symmetry 3 pions (isospin equals 1) can not couple to zero isospin."...

Hi all, I'm having trouble understanding the short lifetime on the neutral pion. I understand that in the residual strong interaction between nucleons, the range of the virtual pion is limited by Heisenberg's uncertainty relation for energy, which thus limits its lifetime. I don't...

How is it possible to have a pion that is made up of a linear combination of quarks? I mean, what are the physical constituents of the neutral pion? is it uubar or ddbar? Or does the linear combination mean that there is a 50 50 chance of a neutral pion being a made of uubar and ddbar?

I'm not sure whether this should go in this forum or the Advanced forum, but here goes. Homework Statement Given: A pion+ decays into muon+ and neutrino, \pi^+ \rightarrow \mu^+ + \nu neutrino mass approaches zero, and the pion is initially at rest. Problem statement: Use...

I have one stupid question: Is it true that the difference of proton and nucleon mass is due to the electromagnetic self-energy of the proton? The same question about pi^0 and pi^- mass difference.

Consider this decay: Pion+ -> muon+ + neutrino It says that one can check the longitudinal polarization of the muon+ and this would confirm that the parity is not conserved. Can you explain what this means in simple terms?

The electromagnetic neutral pion decay is a three-point interaction: it decays into two virtual and charged Kaons or Protons, of which one then radiates a photon and then annihalates with the other to produce a second photon. (Obviously, a neutral particle cannot radiate photons directly)...

Hi first time user here. I was hoping someone could please help me with the following question: A moving neutral pion is observed to decay into 2 photons each with energy 80MeV, there being an angle 120deg between their trajectories.Calc i)The total energy of the meson ii)The momentum of...

Hi, i have a particle physics exam in 2 days and am confused on pion decay via the weak interaction, namely: pi[-] ->muon + anti-muno neutrino Thankyou Ray Veldkamp