Decay Definition and 998 Threads

Homework Statement This question actually comes from my chemistry class, but I believe it is more suited for this forum. When the process of Electron Capture occurs, proton + e --> n, an x-ray is emitted. Why is that x-ray emitted and not a photon of lower energy. Homework Equations No...

I was working on calibrating some newly purchased software onto our lab computers when I noticed that the decay spectrum on the screen did not look exactly as it does on published material. I attribute this to background radiation effects (correct me if I am wrong please), so I decided the best...

Homework Statement This problem involves calculating the age of plant material from which 3 radioactive disintergrations per minute per gram of carbon are detected. During its lifetime, the plant took in carbon from the atmosphere. Of this carbon, for every 1012 atoms of normal 14C, there was...

Homework Statement Homework Equations N=N0e-λt The Attempt at a Solution I can do all of part (a) but I'm stuck on part (b). I don't even know where to begin. I just have no idea what to make of this question. Could someone prod me in the right direction ?

Hello, my question is : C60 ---> Ni60+e-+anti-neutrino why does Co60 decay to an excited state of Ni60 and not directly to its ground state? and why does the Ni emite two photons (first transition from the second excited state to the first excited state and from the first excited state to...

Hello everybody, I'm assigned to do particle physics home, which I don't really understant because I'm a freshman and I have choosen it as a free subject. Obviously, that was a mistake. I have been reading a book, but I'm not sure if I understand everything. Homework Statement A particle of...

Note: I'm only talking about real photons, no virtual particles. The argument that Griffiths gives, is (p79) and although I have respect for Griffiths, I'm wondering if this isn't a fallacious argument: the photon might not have mass, but it has energy... Another argument might be (I'm...

Hello, The Feynman graph of muon decay is and I asked my professor if we could also write and he said no, because then out of nothingness an electron and an (anti)electron-neutrino would appear and send out a boson to the muon. However, I was not very convinced, so I wanted to double...

If a particle decays via A →B + C, and A had some initial non-zero momentum, is it possible for either B or C to be stationary? I can't seem to find a restriction on this from energy conservation or momentum conservation. From energy conservation, the stationary particle B still contributes...

Homework Statement I have a question in my coursework where I don't know where to start. I've got Nickel decaying post the explosion, I've got a time t, I've got an energy release per nucleus of Nickel, I've got a decay constant, I've got a light curve decay half life, and I've got a...

How can I efficiently calculate the amount of material decayed after a specific time in a two-step decay chain? In my specific example, I have 56Ni -> 56Co -> 56Fe. The half life of the first process is 6.1 days, the second - 77.7 days. How can I accurately calculate the amount of 56Fe that...

"Neutrons don't decay in nuclei because no available states" incorrect? Hello, If I understand correctly, the argument for a neutron (usually) not decaying when in a nucleus, is that the resulting proton would then have to occupy a high energy level, the lower levels already being occupied...

Hello, I'm taking a particle physics class and we're using Griffiths' book "Introduction to Elementary Particles". I was reading in it but two statements in it (on the same page, for reference p33 in the second edition) struck me as weird, and as I would greatly appreciate if anyone could...

Hey guys, back again for some help if that's okay! I've derived a formula for an electromagnetic wave entering a material, as \underline{E}e^{-\frac{x}{\delta}}e^{i(\frac{x}{\delta}- \omega t)} x=direction of propagation t=time \delta=skin depth As you can see this describes the wave...

Homework Statement 6. Three disease-carrying organisms decay exponentially in seawater according to the following model: P(t) = Ae-1.5t + Be-0.3t + Ce-0.05t t 0.5, 1, 2, 3 , 4, 5, 6, 7, 9 p(t) 6, 4.4, 3.2, 2.7, 2, 1.9, 1.7, 1.4, 1.1 Estimate the initial concentration of each...

Does anyone know why the $$\rho^0\to\pi^0\gamma$$ decay is suppressed? I've been working on it, and so far I think it can conserve parity, charge conjugation, angular momentum, etc. But the PDG indicates that it basically never happens. Why? Thanks!

Hey why do we observe the Ʃ(minus) decay into n+e+anti-e-neutrino?But never Ʃ+--->n + positron+ ve( electron neutrino)

I am reading Mukhanov's 'Physical Foundations of Cosmology'. He claims that in the minimal SU(5) model, CP violation of a heavy SU(5) gauge boson X decay arises at the tenth order of perturbation theory. Is that correct? The tenth order perturbation theory would lead to a very complicated...

I am trying to revise for PhD, going over MSc work. Could anyone help me with this question? Homework Statement A pion traveling at speed β(=v/c) decays into a muon and a neutrino, π→μ + \nu. If the neutrino emerges at 90° to the original pion direction at what angle does the muon come off...

I am not quite sure why there are only four types of decays, alpha, beta plus and minus, and electron capture. I know that heavy nuclides undergo alpha decay because it is a fast way to loose 2 protons and 2 neutrons, also that the alpha particle is very stable. For beta plus and minus...

Question: find the rate of change of (s) with respect to time(t), is inversely proportional to the square root of (s) Write a differential equation for this statement. Find the general solution to this equation If initially (s)= 100, and after six seconds (s)= 144, what is the value of...

Homework Statement Consider positronium decay. Show the magnitude of the momentum for each gamma ray is m_0c where m_0 is the mass of the electron. Homework Equations E=\sqrt{p^2c^2+m^2c^4}, p=h\nu/v The Attempt at a Solution I'm not sure how to start this one, though I...

Homework Statement An energetic muon is created by the interaction of a cosmic ray 20 km away from the surface of the earth. How energetic does the muon have to be to be detected on Earth before it decays with a 10% probability? For a single muon, what is the probability that it will not...

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Homework Statement I was looking at http://hyperphysics.phy-astr.gsu.edu/hbase/electric/elesht.html (scroll down a little on the link) Homework Equations The Attempt at a Solution Would it be correct to say that the decay in the electric field between the plates is...

I don't understand where radioactive decay comes from. Everything I've read discusses how the environment can influence the decay (for example, neutrons in different nuclei decay with different speeds), but I couldn't find an explanation of what is the underlying cause of the decay. If the...

Homework Statement Given the followin[Sg decay chain- X→Y→Z Solve for Nx(t), Ny(t), Nz(t) for the case of Rx(t)=\alphat and assuming Ny(t)=Nz(t)=0 Homework Equations dNx(t)/dt = -\lambdaxNx(t) + Rx(t) dNy(t)/dt = -\lambdayNy(t) +\lambdaxNx(t) dNz(t)/dt = -\lambdazNz(t) +\lambdayNy(t) The...

(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...

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.

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...

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...