Decay Definition and 998 Threads

(original question) Does the electric charge of an isolated block of radioactive material increase, assume that all emissions are reabsorbed? Subsequent edit: I guess if the body were isolated and emissions escaped the body, a charge would build up until the capacitance of the body is...

Hi guys, I'm working on a problem involving electrical signals which have components which appear to be decaying exponentially. I think my problem is analogous to radio-active decay. I would like to find the probability that there are N particles remaining after K half-lives. To clarify...

Estimate the decay heat rate in a 3000 MWth reactor in which 3.2% mU-enriched U02 assemblies are being fed into the core. The burned-up fuel stays in the core for 3 years before being replaced. Consider two cases: 1. The core is replaced in two batches every 18 months. 2. The fuel...

I understand how beta decay works on a fundamental level, in that either an up or down quark in the one of the nucleons decays into an up or down quark and in the process, a W boson is emitted which in turn decays into an electron and an electron antineutrino or opposites thereof depending on...

I am trying to figure out how fast the Higgs decays and how far it travels in a detector at the LHC. Figure 2.5 in http://www.hep.lu.se/atlas/thesis/egede/thesis-node14.html gives decay widths of the Higgs as a function of its mass. For a Higgs of 125 GeV, it is 0.002 GeV. Using the...

Hello there, I was just reading some articles on Wikipedia.org and found an article on proton decay. I will quote a part of it: How would that be visualized? I've got a basic understanding of particle physics, but these concepts seem rather advanced, yet, I insist on wanting to understand...

Hi I'm wondering if someone could help me out finding the Q-value fom a beta minus decay. It's a 90Y → 90Zr + e All sources I have says that the energy released is 2,28 MeV, but when i calculate i get 1,78 MeV So far, I've looked up the mass of the 90Y and the Zr90 and the electron...

There has been a suspicion that solar neutrinos can interfere with the rates of radioactive decay in isotopes. Could this mystery (somehow?)be tied to the neutrinos that are being recorded as 'faster than light'? For example the neutrinos pick up extra energy from the radioactive decay...

I hope you don’t mind me asking this OPERA question here but I think it’s more of a QM question. I just watched NOVA Ghost Particle and it got me thinking. The only problem is that my brain isn’t strong enough to hold all that I’m reading about this experiment. From what I gather, the CERN...

Hi guys, I'm developing a video game that centers around the creation of atoms. I know that I'll have to suspend reality to some degree to make the game playable, but I also want to be careful not to spread horribly inaccurate misinformation with the game. Actually the idea is to make the...

Homework Statement The equilibrium concentration of C14/C12 ≈ 1.5×10−12 A 2.5 g sample of Carbon from an old tree fragment has an activity of 4.57 decays per minute. How old is the sample? Homework Equations I'm pretty sure I use A(t)=λN(0)*exp(-tλ) but I am having trouble calculating N(0)...

Quantum Zeno Effect and quantum "decay" Howdy, My understanding of QM is mostly mathematical (I have a basic understanding of the Hamiltonian of something like the particle in the box, and the rest of what I know is from Quantum Information Science, with very little physics knowledge), so...

Hello, Does anyone know how to solve an equation of the form: e-ax+e-bx=c Where a,b and c are constants? This left side of the equation represents the sum of two exponential decay processes, one fast and one slow. I want to know for what positive value of x the expression on the left...

dHomework Statement the half life of U234 is 245.5 years. It decays by α emmission to Th230 whos half life is 75.38. there are 10^6 atoms of U234 and 0 atoms of Th230 at t=0. At what time will the number of atoms of each type be equal? the half life of U234 is 245.5 years and half life of...

This question is mostly about how to interpret notation used in Particle Physics. At lowest order the rate of b\rightarrow s\gamma is proportional to \langle B_p|b^\dagger b|B_p\rangle where p is either u or d labels and b, b+ are creation annhilation operators. However, I am unable to...

What are flavor arguments that prevent a gluon from decaying into quark and photon, or anti-quark and photon, etc?

I have read that 3 pion decay of the eta is not allowed as a strong reaction, but proceeds as an electromagnetic interaction. I do not see why it is strong forbidden.

Homework Statement Muon with mass 80m is at rest. Muon decays into photon and particle Qm. The photon has an energy of E=60m in the +x direction. Find all of the other components.Homework Equations Vx= Px/E m^2=E^2-P^2 Pt=E Ignoring the Y and Z components of the Four-Momentum as they are...

Why is it that the differential cross section for processes like Inverse Muon Decay (IMD) are always given in the CM frame? Every paper I have seen that discusses Inverse Muon Decay gives the differential cross section in CM frame. Is it very hard to calculate the differential cross section in...

Homework Statement The atomic mass of 55 25Mn = 54.938047u and that of 55 26Fe=54.938296u. Explain which of the three possible β-decay processes involving these two nuclides are forbidden, and which can occur. For decays which can occur, describe the energy spectrum of the products...

Hello there, I am looking at the decays of Heavy sterile neutrinos in the their mass states to Z bosons. Using the feynman rules, how would I go about calculating the decay amplitude. I have only ever seen cases where the Z boson is a propagator. Would my expression look something like this...

I am trying to work out the Feynman diagram for the decay D^0\to K^++\pi^- But I can't seem to get it unless the D meson is its own antiparticle. Could someone tell me if this is the case? Ie, is |\bar{u}c\rangle = |u\bar{c}\rangle? Thanks

Homework Statement The radioactive nuclides released into the atmosphere by the Chernobyl nuclear accident in 1986 included both 131I (t 1/2= 8 days) and 137Cs (t 1/2= 30 years). Given that 5 times as many 137 Cs as 131 I are present in the reactor in steady state, and that 131 I is produced in...

Hi all. I'm looking at the decay of a neutral ρ meson to two neutral π's. I think it is disallowed but I can't figure out why. The J^{P} of the ρ is 1^{-} and 0^{-} for the neutral π's. The formula P(ρ^{0})=(-1)^{L}P(π^{0})P(π^{0}) then says that the decay is allowed provided the π's are...

Homework Statement B mesons can be created through the reaction chain e+e- → \Upsilon(4S) → B+B- by colliding beams of electrons and positrons head-on at centre-of-mass energy equivalent to the mass of the \Upsilon(4S) resonance. a) If the electron beam energy is 8GeV, show that a positron...

Decay of tauon into pion and neutrino... Hello all. I have a question. One of the weak decays of a tauon(energy 20GeV) is to a charged pion(rest mass 139.6Mev/c^2) and a neutrino(take the neutrino to be massless). What condition results in the maximum energy of the pion after the...

Homework Equations I was given all this information... I cannot figure it out whatsoever. I would post my attempts but there were too many. Any ideas would be helpful. I know the answer is 5.09 as the half life Decay Constant of Copper 66 Sources do not emit radiation at a constant...

Hi, Explain in terms of the number of nucleons and the forces between them, why argon-36 is stable and argon-39 is radioactive. My first doubt regards the number of nucleons. If a nucleon is the collective number of neutrons and protons, if we take carbon 12 for example, does it have 6 or...

Typical radio active decay question Half time = 1 year λ = ln 2 here Q 1: if we have 1024 atoms at t=0, what is the time at which the expected number remaining is one. Easy, I get 10 years Q 2: The chance that in fact none of the 1024 atoms remains after the time calculated in c...

I need some clarifications on the following concepts: 1.When an α-particle is released by a radio active sample, it loses a charge of +2. Similarly, when it loses a β particle it gains one positive charge. But there is no change in the number of electrons in the outer orbits of the radio...

In a reactor and sepertation plant complex, nuclide A is produced in pure form, without any contamination by nuclide B. A has a half life of 23minutes and B has a half life of 23days. A is a beta only emitter whereas B is a beta and gamma emitter. If A has been purified in a reatcor and...

I think I understand the basics of the SM and know that the W and Z bosons are the mediators of the Weak Force. I also understand from chem the basics about nuclear stability (ratio of protons to neutrons, valley of stability/nuclear binding energy, etc.). What I'd like to know is what the...

The equation I used for these are: If N=Noekt then DN/Dt=N0kekt so the two problems I have trouble with is A radioactive substance has a decay constant (k) of -.0539 per year. If 371 grams of the material is initially present, what is the instaneous rate of change of the substance at times...

Problem is: have a mother and daughter sample, A and B respectively. both are radioactive. The number of daughter nuclei at time t is given by (*): n(t)=\frac{N_{0}\lambda_{A}}{\lambda_{B}-\lambda_{A}}[e^{-\lambda_{A}t}-e^{-\lambda_{B}t}] where N_0 is number of mother nuclei at t=0 and n(t)...

Can someone describe the Feynman diagram for the Sigma plus decay to a positive pion and a neutron? I'm fine with the primary decay to the neutral pion and a proton. There appears to be insufficient down quarks created.

Z and W bosons have very short lives. I assume their decay is exothermic? Is this true? I've seen various feynman diagrams showing how these particles decay, but I'm having trouble verifying that their decay is exothermic. Also, does either of their decay emit dangerous radiation, or is it...

Hello, I am curious. Eventhough, the half-time of an element is always the same. Why not we can't find quarter of elements vanish time, because; half life is directly proportional, 10gr 10 min -> 5gr 20min. if 10 gr vanishes in 10 min, 2.5gr vanishes in 2.5 min for 20gr radioactive material.

Hello! I have read that in the case of beta decay, a neutron becomes a proton neutron = proton + electron + antineutrino but the electron and antineutrino are ''materialized'' by the emission of an intermediate w- boson. What does ''materialize'' mean in this context? I have thought of the w...

Homework Statement I learned that radio-decay is exponential; say if A decays to B with constant y1 and B decays to C with constant y2 and C is stable, N1 is nuclei in A while N2 is nuclei in B. N1 = N0e-y1(t) Homework Equations Then, I tried writing the decay equation for B, and hit...

Does this ever happen? p + \gamma \rightarrow n + e+ + \nu_e It seems possible, if the \gamma has enough energy, but I wonder if anyone can confirm that it happens.

Gamma decays are e.m.waves ..then how describe gamma decay in terms of energy levels?

Why is the Thorium decay series called 4n? I've looked it up but the explanation isn't clear

The fact that radioactive decay and continuous compound interest end up with the same formula (with the "rate" being negative in the former and positive in the latter) seems to me to be more a result of the ubiquity of the exponential function in solving differential equations than any common...

Hello, This may sound silly, don't be afraid to let me know just how silly though! I've read that predictions are made using the standard model. I do not know the details of this process. I understand pair production occurs randomly in a vacuum, but I wondered if there was an underlying...

Hello, I was looking at the quark masses and had this doubt regarding the muon decay: Why can't the muon decay into up and down quarks (plus neutrino). I know the explanation is because muon doesn't exhibit hadronic decays because its mass isn't big enough m_\mu=107MEV. But I just saw that...

Can someone explain this excerpt from my textbook please? "IF nucleus A was made from its constituents (Binding energy) and it released 400MeV, but making nucleus B(product) releases 405MeV. Therefore if A changes to B, 5 MeV of energy must be released. This excess energy is given to the...

Homework Statement In \alpha decay a nucleus X at rest decays to a daughter nucleus Y and an \alpha particle. Conservation of momentum and kinetic energy gives: M_{\alpha}v_{\alpha}+M_{Y}v_{Y}=0 \frac{1}{2}M_{\alpha}v_{\alpha}^{2}+\frac{1}{2}M_{Y}v_{Y}^{2}=Q Where the Q value is the...

I am not quite sure wheather this is the appropriate section. (since the question is about an experiment). I wondered about the following -when the Kamiokande-colaboration is going to release new results on proton decay bounds- since their last new bounds where in 2009 (Judging from their...

Why can’t decay heat be harnessed and used as an energy source to safely power down/cool a nuclear reactor? I have been wondering about this since the reactor incidents in Japan as it appears a tremendous amount off energy must still be dissapated after the shutdown of a nuclear reactor in...

Please teach me this: In QTF theory of Schroeder,chapter 13.1 saying: Just at t=0(t=\frac{T-T_{c}}{T_{c}}),the correlation should decay as power law. Define the exponent \eta by the formula: G(x)=\frac{1}{x^{d-2+\eta}} where d is Euclidien space dimension. I do not understand why at...