Beta decay Definition and 148 Threads

In nuclear physics, beta decay (β-decay) is a type of radioactive decay in which a beta particle (fast energetic electron or positron) is emitted from an atomic nucleus, transforming the original nuclide to an isobar of that nuclide. For example, beta decay of a neutron transforms it into a proton by the emission of an electron accompanied by an antineutrino; or, conversely a proton is converted into a neutron by the emission of a positron with a neutrino in so-called positron emission. Neither the beta particle nor its associated (anti-)neutrino exist within the nucleus prior to beta decay, but are created in the decay process. By this process, unstable atoms obtain a more stable ratio of protons to neutrons. The probability of a nuclide decaying due to beta and other forms of decay is determined by its nuclear binding energy. The binding energies of all existing nuclides form what is called the nuclear band or valley of stability. For either electron or positron emission to be energetically possible, the energy release (see below) or Q value must be positive.
Beta decay is a consequence of the weak force, which is characterized by relatively lengthy decay times. Nucleons are composed of up quarks and down quarks, and the weak force allows a quark to change its flavour by emission of a W boson leading to creation of an electron/antineutrino or positron/neutrino pair. For example, a neutron, composed of two down quarks and an up quark, decays to a proton composed of a down quark and two up quarks.
Electron capture is sometimes included as a type of beta decay, because the basic nuclear process, mediated by the weak force, is the same. In electron capture, an inner atomic electron is captured by a proton in the nucleus, transforming it into a neutron, and an electron neutrino is released.

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  1. C

    A Accelerating an electron in beta decay

    The electron created and emitted in the beta decay of a proton has an initial velocity close to the speed of light. When I try to calculate, not taking into account relativity, the force needed to accelerate an electron to that velocity over a distance the size of a proton, I get about 45 N...
  2. kiwaho

    I Can electron beam accelerate electron capture beta decay?

    Some nuclides undergo decay of electron capture or beta plus. Can electron beam with appropriate energy accelerate electron capture beta decay? Same scenario: If I am looking for something, and my friend kindly hands it over to me, then I say thanks, because my seeking time is shorten.
  3. G

    B How do beta particles remove electrons?

    Hello all, I'm just learning about beta decay and the emission of beta particles. I have come to an understanding that this is ionising radiation because it has the ability to remove electrons and turn the molecules it interacts with into ions. I've looked on the Internet for this information...
  4. C

    I Can We Neglect Electron Binding Energies in Beta Decay Calculations?

    Hi, I was reading the wiki article here on beta decay and energy release: https://en.wikipedia.org/wiki/Beta_decay#Energy_release In obtaining a condition on the masses of the initial and final atoms we neglected the difference in electron binding energies of the two atoms. Does this mean we...
  5. amyy

    Why Does Tritium Beta-Decay to Helium-3?

    Homework Statement 3H has more tightly bound than 3He. Why is it, then, that 3H beta-decays to 3He? Homework Equations I also wonder what is the physical meaning of the value mass excess Δ(Z,A)≡[M(Z,A)-A]c2, or it is just for the convenience of calculations. The Attempt at a Solution B/A of...
  6. S

    I How do neutrinos conserve angular momentum?

    I'm learning about beta decay and as I understand in beta decay we get: neutron → proton + electron And since all these have spin 1/2 we have that the conservation of angular momentum is not conserved. The neutrino with spin 1/2 is proposed to also exist in the process to solve this so that...
  7. M

    How can beta decay have energy of 3-4 MeV

    First of all let me tell that I am a high school student and I have no background in particle physics. If we apply the Heisenberg's uncertainty principle to an electron confined in the nucleus it tells us that the energy of the electron must be something like 3.8X10^8eV .. but in a beta decay...
  8. J

    B Is Decoherence Possible Without Collapse?

    Beta decay, quantum fluctuations, even random vacuum polarizations are all manifestation of collapse, isn't it? The arguments being that in pure unitary wave function, there will be no phase randomization of any kind. Do you consider beta decay as example of decoherence? For decoherence to...
  9. J

    What Causes Beta Decay and the Role of the Weak Nuclear Force?

    I am familiar with the proton:neutron ratio and stability but what about this instability actually causes a quark to emit a boson and change flavour? And what does this have to do with the weak nuclear force? Thanks
  10. karakele

    Concerns about double beta decay plus/double electron capture

    Hello fellas! Ok, so we have the isotope Nickel-58 which can decay (still theoritically) to Iron-58 through double beta decay plus (bb+), my question is... imagine this decay is actually demonstrated (just figure it), so the transmutation into the iron isotope actually works... would the ejected...
  11. R

    Fermi/Coulomb correction factor for beta decay

    Hi all, Fermi introduced a multiplicative correction factor in order to correct for the effect of the Coulomb field on the resulting energy distribution of ejected beta particles (i.e., either electrons or positrons) following a beta decay reaction. The result is that positrons are accelerated...
  12. L

    Interpretation of a before $\gamma^{5}$ in J$_{\alpha}$

    Could you explain what's the interpretation of a before \gamma^{5} in this current: J_{\alpha}=\bar{\psi_{e}}\gamma^{\alpha}\left(1-a\gamma^{5}\right)\psi_{\nu_{e}} +\bar{\psi_{\mu}}\gamma^{\alpha}\left(1-a\gamma^{5}\right)\psi_{\nu_{\mu}}? And will this factor complicate calculations of decay...
  13. U

    Why doesn't Rubidium decay to Strontium?

    Both ##^{87}_{37}Rb## and ##^{87}_{38}Sr## are odd-even nuclei, so we can ignore the pairing term ##\delta##. I tried to calculate the most stable Z for a given A by finding ##\frac{\partial B}{\partial Z} = 0##. That gives the most Z-stable value of ##Z_0 = \frac{2\gamma A}{4\gamma + \epsilon...
  14. R

    Quick question on the mass condition for beta decay

    For β- we have: ##M(A,Z)>M(A,Z+1) + m_{e} - m_{e}## An electron is removed from the atom and therefore we need to take that away from the M(A,Z+1) term But for β+ we have been given: ##M(A,Z)>M(A,Z+1) + m_{e} + m_{e}## What is this saying? A positron is emitted, therefore shouldn't we minus...
  15. U

    Fermi Golden Rule - Beta Decay

    We consider the following beta decay: ^A_ZX \rightarrow ^A_{Z+1} Y + e^{-} + \nu_e The Fermi golden rule is given by: \Gamma = \frac{2\pi}{\hbar} |A_{fi}|^2 \frac{dN}{dE_f} Reaction amplitude is given by ##A_{fi} = G_F M_{nucl} ## while density of states is given by ##dN = \frac{4 \pi...
  16. G

    Proton to neutron conversion at relativistic energies

    The reaction p→n+e++νe is common inside nucleus. But it not considered when we talk about free particle and reason is simply given mass of products being larger than reactants. Now my question is if there is a high energy proton having total energy in order of 2 GeV or let it to be 100 GeV (To...
  17. K

    Answer Gold Beta & Alpha Decay Questions

    Homework Statement Use the periodic table to find the daughter nucleus after a gold nucleus (Au) undergoes beta decay. What would be the result if the gold nucleus had undergone alpha decay instead? Homework EquationsThe Attempt at a Solution Beta Decay: A=196.96655 Z=80 Au Alpha Decay...
  18. F

    Beta Decay: Unstable Nuclei & Why It Occurs

    I've started studying physics at a basic level and I've ready that beta decay takes place when the number of neutrons exceed the number of protons in a nucleus. Why does this excess number of neutrons compared to protons make the nucleus unstable? Also, what does an unstable nucleus mean?
  19. G

    Mass Loss in Beta Decay: A_(z+1) Y vs Physics Fact

    Homework Statement from the physics fact in the photo, i know that the daughter nucleus is a positive ion... but , referring to the part 2 , finding the mass loss in beta decay in terms of atomic mass , it says that A_(z+1) Y has extra one orbitting electron comapred to the parent nucleus. this...
  20. C

    Beta decay and inverse beta decay is different?

    So in beta decay I know a neutron can decay into, proton, electron and antineutrino (Or, neutrino, since they're both the same?) But anyhow, regardless of the neutrino, in neutron stars electron degeneracy doesn't hold and electrons combine with photons to form neutrons. But isn't that...
  21. R

    What Is Beta Decay?

    Anyone able to explain Beta decay?
  22. S

    Can Beta Decay Occur to a Ground State in Nuclear Physics?

    What is difference between beta particle and electron? I mean in spin, mass or other properties.
  23. S

    Understanding W-Boson Decay: Electron & Anti-Neutrino Formation

    How W- boson decay into electron and anti neutrino?
  24. T

    Beta Decay Q&A: Quarks, W Bosons & More

    In beta decay, is the W boson created by the change of a quark or does it cause the change? Also, I don't fully understand where the W bosons come from or how they are created. If someone could please explain this to me, I'm very confused.
  25. S

    Showing Beta Decay (Feynman diagrams?)

    Would someone please tell me how I would show Strontium-90 decay into Yttrium 90(and emitting Beta particles)? Would I need to use a Feynman diagram? Thank you!
  26. S

    Electromagnetism and Beta Decay

    Hello! I am participating in a STEM fair(I am a middle schooler), and my scientific question is : Does the angle of the particle trails increase from beta decay when you introduce an electromagnetic influence? I have been at a loss for finding a helpful site. The ones that I have come...
  27. Q

    Calculating the Age of 1.4g of Charcoal Using Beta Decay

    Homework Statement Suppose you have a 1.4g sample of old charcoal. It produces 0.7 beta decays per minute. How old is the charcoal. Given: 1g of carbon current day has 6.36x1010 atoms of 14C Homework Equations N = Noe-rt N = number of atoms in the sample (current-day) No =...
  28. B

    Date An Object Using Carbon Dating, Beta Decay

    Homework Statement An old wooden tool, containing 75.0 grams of carbon, is found in an ancient tomb. The tool emits 500 electrons/minute from the beta decay of 146C. How old is the wood from which the tool was constructed? Given: The half-life of 146C is 5730 years, the ratio of 146C to 126C in...
  29. P

    Does the Electron Spectrum in Beta Decay Indicate Neutrino Mass?

    Homework Statement A nucleus N1 decays through beta decay to nucleus N2. The mass difference between N1 and N2 is ΔM. The differential decay rate may be written as: dw=p(E_e)dE_e p(E_e) \propto E_e (E_e^2-(m_ec^2))^{1/2}(\Delta Mc^2-E_e)((\Delta Mc^2-E_e)^2-(m_vc^2)^2)^{1/2} where Ee is the...
  30. P

    Beta decay of deuterium and triterium

    Homework Statement Explain why deuterium cannot undergo beta decay or produce a stable nucleus, while tritium can. Homework Equations n/a The Attempt at a Solution There was nothing in the lesson that really explained this, and the only reason I can find online is because deuterium...
  31. G

    Particle energies after beta decay in different frames

    Hi, I am reading in some books that after the \beta-decay of neutrons, the maximum energy of the resulting electron is a bit less than 800 keV. In some cases, however, I see that in e.g. some studies that try to extract the electron energy from \beta-decay of neutrons with some Monte Carlo...
  32. H

    Determining the atomic number, mass number, and chemical name during beta decay

    Determining the atomic number, mass number, and chemical name during beta decay! Homework Statement The image below shows the element Thorium with the atomic number listed above and a mass number of 233. This element undergoes two successive beta decays. The resulting nucleus will have an...
  33. M

    An Electron coming from the nucleus in Beta Decay?

    Hi guys, essentially I have been talking with my Physics teacher about Beta Decay and she was saying that sometimes electrons come from the nucleus because of the quarks in the protons and the neutrons? I didn't fully understand it so I have likely got it wrong what she was trying to explain. Do...
  34. X

    Beta Decay of He3 Atom: Electron Emission vs. Shell Occupancy

    Does this decay leave the He3 atom with only one electron? The only decay productsas far as I can tell are the electron and antineutrino, so it seems like the atom would only retain the original H3 electron. Now if that's the case, why is the beta decay electron emitted rather than fitting...
  35. X

    Kinetic energy of electron after beta decay

    Is that a constant? If not, is there an equation that allows us to calculate its kinetic energy based on the properties of the atom it came from?
  36. C

    Calculate the KE of an electron emitted from the beta decay of a neutron

    Homework Statement What is the maximum kinetic energy (in keV to 3 significant figures) of an electron emitted in the beta decay of a free neutron? Write down the decay equation using accepted notation. Mass of a Neutron: 1.008665 u Mass of a Proton: 1.007276 u Mass of an Electron...
  37. X

    How are W Bosons Formed in Beta Decay

    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...
  38. H

    Beta Decay Processes of 5525Mn & 5526Fe

    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...
  39. G

    What is the Reason Behind Beta Decay Not Creating an Ion?

    Beta decay is when a neutron creates a proton and an electron and the electron is then expelled, right? So I was wondering, why would the new atom formed not be an ion? If the neutron became a proton, the mass number should stay the same, and the atomic number should increase by 1 since...
  40. C

    Beta decay problems, not getting the right answer

    Homework Statement a) What is the energy of the neutrino, if a phosphorus-32 atom (31.97390 u) beta-decays into a sulphur-32 atom (31.97207 u), and the kinetic energy of the accompanying electron is 0.90 MeV? (answer: 0.25 MeV) b) A boron-12 atom (12.01435 u) beta-decays into a...
  41. Andy Resnick

    How is overall charge neutrality conserved in beta decay?

    This is probably a dumb question, but a student asked me and I can't figure out the answer: When a nucleus decays via beta decay, for example (in poorly formatted text): 55 Cs → 56 Ba + e− + ν How is overall charge neutrality conserved? Clearly, the reaction appears to conserve...
  42. O

    What nuclei are stable against beta decay?

    I know odd-odd nuclei are generally unstable against beta decay as the pairing term in the semi-empirical mass formula is less than zero, and I know even-even nuclei are generally stable, but I don't get the rules you apply for even-odd or odd-even nuclei. Do you have to work out the binding...
  43. J

    What Is the Decay Process for Be7 to Li7?

    Homework Statement Sorry charge conservation is not really part of the problem. Question I'm stuck on is: What is the process of decay for Be7 to Li7Homework Equations Qb+=[M(Be)-M(Li)-2Me]c2 Qb-=[M(Be)-M(Li)]c2 Qe=[M(Be)-M(li)]c2-Bn The Attempt at a Solution I know that t is not beta minus...
  44. U

    Feynmann diagram for beta decay, direction of arrows confusion

    For beta minus decay, I know the reaction is given by neutron -> proton+electron+anti(electron)neutrino. This is an image of the Feynman diagram for the reaction: http://tmp.kiwix.org:4201/I/280px_Beta_Negative_Decay_svg.png I get that the neutron changes to a proton releasing a w-...
  45. S

    Beta Decay Charge Conservation

    Hey so, I was just wondering: If Carbon-14 (6 protons, 8 neutrons) decays into an electron, a neutrino, and Nitrogen 14 (7 protons, 7 neutrons) How is charge conserved? I get that nucleons are conserved, but if nitrogen-14 is neutral, then it has 7 protons and 7 electrons, versus Carbon...
  46. J

    Beta decay Charge conservation

    In beta decat the u quark fromthe proton and the d quark from the neutron interact to produce a electron and it's neutrino. I'm wondering about the charge conservation of this process because a neutron has zero charge and a proton has charge of 1. How do we end up with a electron charge of -1 at...
  47. H

    Beta decay and Heisenberg principle

    Homework Statement One could imagine that beta decay was due to a electron initially inside the nucleus and than leaving it. Proof by using Heisenberg uncertainty principle that this is not possible. There is a hint which says you can use energy spectra and values for the energy of beta...
  48. S

    Coulomb correction for beta decay spectrum

    Hello I am re-reading some of my old textbooks and have come across a simplified (non-relativistic) term used to correct the beta decay spectrum for the coulomb effect of the nucleus on the ejected beta particle. The expression is; F(Z,E) = (2*Pi*n) / (1 - exp(-2*Pi*n)) where n =...
  49. S

    Influencing Beta Decay: Electron & Neutrino Density Effects

    Because electrons are known to be participants in the beta-decay reaction, electron density has been shown to influence the rate of beta decay: http://prl.aps.org/abstract/PRL/v98/i25/e252501 http://www.phys.ncku.edu.tw/mirrors/physicsfaq/ParticleAndNuclear/decay_rates.html...
  50. Q

    Nuclear Beta Decay (Parity, deta[L])

    I do not get the concepts of the parity change and how do I find the deta (l) for beta decay. Please Help! Classify the following decays according to their degree of forbiddenness, all ground states decays. 89Sr (5/2+) -> 89Y (1/2-) 26Al (5+) -> 26Mg (2+) 97Zr (1/2+) -> 97Nb (1/2-)...
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