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.
Dear community,
I am trying to construct the decay chains and the decay radiations from ENSDF files. Until now, I have used the ones included in the ENDF6 file format such as JEFF3 or ENDFBVIII etc... However, I have been told that ENSDF was especially done for decay data.
I found the software...
Hi!
Instead of just describing my procedure and all my derivations, I really just want to ask if my approach makes sense (actually I have 2 options) to calculate the maximum energy. I am considering c=1 and the problem suggests to consider the neutrino massless:
For the first decay, ##Z...
When the ##\psi(2s)## particle decays also the following two transitions are observed
$$\psi(2S) \rightarrow \gamma + \eta({1}^S_0)$$
$$\psi(2S) \rightarrow \gamma + \chi_{c0}({3}^P_0)$$
The branching fraction for the first decay is about ##3.4*10^{-3}## while it's ##9.7*10^{-2}## for the...
Right, so I thought I'd done this correctly but clearly not because my velocity is greater than the speed of light, where have I gone wrong?
P = (M, 0, 0, 0)
p1 = (E1, p1x, p1y, p1z)
p2 = (E2, p2x, p2y, p2z)
P = p1 + p2
p2 = P - p1
square each side
to get (p2)2 = P2 - 2Pp1 + p12
therefore
(m2)2...
I've tried using gammamc^{2} = E1 + E2 but how do i find gamma?? If i try to use the kinetic energy then I just get gammamv^2 = 1gev but i dont know v? very confused
So I know that the total energy of the system initially is 775.5MeV, because the meson is at rest. Also by conservation of energy I know that the total final energy of the system is the same thing. I also know that the initial momentum of the system is 0 because the particle is at rest. This...
Hello everybody!
I have a question regarding the forbidden decay ##\rho^0 \rightarrow \pi^0\pi^0##, but it is a general doubt.
My book states that one of the reasons why the decay is forbidden is Bose-Einstein statistics, the final state of two equal pions must be in an antisymmetric state...
First of, I have no idea what I'm supposed to do with the neutrinos and the photons. Can somebody explain how to handle these? The rest of what I tried is quite straight forward
$$\begin{align*}\Delta E &= 4M_p - M_{He} - 2 M_e + E_{\text{Neutrino and Photons}}\\&= 4M_p - (2[M_p+M_n]-E_B) - 2...
In a paper on quantum synchronization, they introduce the setup given in the attached 'Fig1.png'. I would like confirm a few concepts regarding this setup. The setup is described in the following way:
The general setup is shown schematically in Fig.1. Two
ensembles, each containing ##N##...
Homework Statement
Homework Equations
(1) E2 = p2c2 + m02c4
(2) E = γm0c2
(3) E = Eγ1 - Eγ2
(4) p = E / c
(5) E = hf
(6) λ = c / f
The Attempt at a Solution
a) Using eqn (1), rearranged p = (E - m0c2) / c , I obtained 2.9 MeV c-1. Not sure if I have the right answer here as I...
Homework Statement
(b)
A nuclear research reactor produces radiation for neutron scattering measurements. A safety procedure shuts the reactor down if a radiation level monitoring detector measures more than 3 counts per minute. In a test, 156 counts are recorded during a random 24 hour...
Geiger–Nuttall rule relates the decay constant of a radioactive isotope with the energy of the alpha particles emitted. Roughly speaking, it states that short-lived isotopes emit more energetic alpha particles than long-lived ones. - wiki
I am trying to understand why there is an inverse...
Consider chain of two radioactive decays ##A \to B\to C##. The equation that regulates ##N_B## is
$${\frac {\mathrm {d} N_{B}}{\mathrm {d} t}}=-\lambda _{B}N_{B}+\lambda _{A}N_{A}$$
I can't understand why the activity of ##B## is get as ##\lambda_B N_B##, for example at page 20 here...
Consider a scattering between two particles a and b that produces two particles c and d: d is stable, while c decays in two other different particles e and f.
The first interaction is by strong force (time of interaction ##t_1\sim 10^{-23}s##, which is also the time of generation of c and d)...
Hey everyone,
I have a question about how "viable" the Quantum Anti-Zeno Effect (AZE) is at lowering decay rates in radioactive nuclei. We know that the AZE can, in fact, reduce the half life of radioactive isotopes, but there seems to be a barrier to that.
AZE states that decay can be...
Homework Statement
A hypertriton (a bound system with a L hyperon together with a deuteron core (proton
and neutron) is produced at the origin of the coordinate, (x,y)=(0,0) with a velocity of 0.94c
(beta=0.94), flying along the x-axis. The mass of the hypertriton is 2.991 GeV/c2
. It decays...
< Mentor Note -- thread moved to HH from the technical physics forums, so no HH Template is shown >
Question:
An experiment is proposed to directly measure the width (Γ) and mass (m_H) of the Higgs boson via the reaction: muon+ + muon- > H.
Sketch a graph of the expected cross section as a...
Homework Statement
I have a mother particle at rest, which decays to a daughter particle. The daughter has mass m, momentum p and energy E and is at an angle θ1.
Now I have to assume that the daughter is emitted at an angle θ2, and the mother is moving along the x axis with velocity βc. I need...
Homework Statement
A particle A (mother particle) with a mass of mA decays to two particles B and C (daughter
particles) with mass values of respectively mB and mC. Calculate momentum of the two
daughter particles, pB and pC. (at first the mother particle is at rest)
Homework Equations
The...
Homework Statement
Show that it is impossible for an ultra-relativistic particle with ##pc>>Mc^2## to disintegrate into two identical massive particles of mass m.
Homework Equations
Conservation of four momentum
The Attempt at a Solution
The four momentum of the ultra-relativistic particle...
Homework Statement
The reaction dd → απ0 (where α is the Helium-4 nucleus and d denotes the deuteron) has never been observed. Why?
Homework Equations
The Attempt at a Solution
[/B]
So I checked first the masses to make sure energy/momentum are conserved and found out that mass of 2d is...
Homework Statement
The current limit on the proton’s lifetime is determined by observing a large body of water for a long time and noticing that no one of the hydrogen nuclei in H2O have decayed. Assuming that the experiment making this measurement has been going on for 10 years, how many tons...
Pronouncing a nuclear reaction like
as "one,zero,neutron + 235,92,uranium yields 141,56,barium + 92,36,krypton + 3,1,0,neutron" is awkward. How is it pronounced by physicists in practice?
Homework Statement
What is the kinetic energy given to the proton in the decay of a neutron when:
a) The electron has negligibly small kinetic energy
b) The neutrino has negligibly small kinetic energy
Homework Equations
Q = (mn - mp - me - mv ) c2 = .782MeV
Where T is kinetic energy, and...
How should I go about using equation 8.18? Link can be found below. In the book, an example is used where
Th-220 --> C-12 + Po-208 with a Q value of 32.1 MeV is used, and it is said to yield
t1/2 = 2.3x106 but for the life of me I cannot reproduce this result. This is what I did:
Going from...
it is known that einstein's theory has been verified and time slows down for particles that should decay in certain time, takes more time to decay if moving fast.
what makes them behave like that, how moving fast makes time to slow down, is it really time or just maybe this has not been...
Homework Statement
A particle of mass M and 4-moment P decays into two particles of masses m1 and m2
1) Find the total energy of each particle (lab frame).
2) Show that the kinetic energy T1 of the first particle in the same reference frame is given by
$$T_1= \Delta M (1 - \frac{m_1}{M} -...
Hi, I recently bought a glow-in-the-dark key chain, similar to http://tinyurl.com/zqf5sxb (image link). It is made from solid plexiglass, with a hollow cylinder in the middle, containing tritium. The electrons from the beta decay presumably hit a fluorescent wall on the inside of the cylinder...
So we are doing Radioactivity lab at second year undergraduate. I am confused about the workings of the silicon radiation detects we are using even though the demonstrators tried to explain. We are detecting beta and gamma radiations by placing sources above a silicon detector that have a small...
[Question]
So I was thinking about Physics for some time and for the sake of
curiosity I've came with this problem:
Let's say we have a liquid flowing into a system with infinite
space.
The flow is constant ( F )
The liquid decays over time with a half life ( λ )
We're looking for the Total...
Homework Statement
A tube containing a isotope of radon, 22286Rn, is to be implanted in a patient. The radon has an initial activity of 1.6 * 104 Bq, a half-life of 4 days and it decays by alpha emission. To provide the correct dose, the tube, containing a freshly prepared sample of the...
Homework Statement
I have the decay
K+ → μ+ + νμ
Calculate:
1. Momentum of μ+
2. Total energy of νμ
3. Mass of K+
4. Speed of μ+
5. Speed of νμ
Homework Equations
The only thing we get are the kinetic energy of μ+ so Kμ+ = 152.53 MeV
and the mass of mμ+ = 105.658 MeV/c2
The Attempt at a...
I've been asked to find the ratio between the cross sections of the two folowing decais:
Using the CKM matrix and the feynman diagrams for both decays, I reach the conclusion that the Ratio is exactly 1. However, consulting this document...
As I understand it muons have a half life of 2.2 microseconds, thus, at the speed of light cannot get to the earth. But based on exponential decay, of every billion muons which head or way, about 70 will actually get here. Using time dilation the full billion will get here.
Do we need a billion...
Hey!
I'm studying some particle physics. I ran into this example of a gluon decaying into a u - anti-u pair. (According to example 9: http://teachers.web.cern.ch/teachers/archiv/HST2002/feynman/examples.htm) How come this happens via strong force. Why isn't a Z0 boson doing this instead?
Thanks!
Hi, I am struggling with a question where they want me to determine whether or not three different decay are allowed.
From what I have understood all decays must follow a set of conservation law. These laws are:
1 Conservation of Baryon number
2 Conservation of Lepton number
3 Conservation of...
Homework Statement
When an instable atom emits alpha or beta particles. Doesn't the overal electrical charge of the remaining atom change? For example when an atom emits alpha decay, a helium core is emitted, this results in the lose of two protons (forthe radiating atom). But doens't this mean...
Hi, How could I rearrange x=x0e^-lambda t into the form y=mx+c, where y is equal to ln x and x is equal to t?
Thank you in advance
I tried to solve the problem myself, by taking the natural log of both sides, this left me with:
ln x = -lambda t * lnx0
However, I am not sure if this answer is...
Hello,
Are there any anthropologists, archaeologists, or geologists around on this board for help? I am trying to teach myself about radioactive decay via beta emission whereby a neutron spontaneously transmutes into a proton, releasing an electron. But, I do not understand the practical side...
Homework Statement
The formula being derived is N=No*e^k*t, from the equation Nn=No/2^n where No is the initial number of particles and the lowercase n in the second equation is the number of half lives. The n in Nn just indicates the number of particles after so many half lives. You might also...
Hi, i'm trying to compute the differential decay of W boson at rest
$$W^+ \rightarrow e^+ \nu_e$$
where the boson has fixed spin along z axis, and so specific cirular polarization. Using Feynman rules i get...
Homework Statement
Hi- i've been doing some questions and came across the following
A high energy particle, travelling towards an observer with velocity v decays to produce a photon with
energy E in the rest frame of the particle.
Find the frequency at which this photon would be detected by...
Inflation , as proposed, leaves the universe cold and empty. The compensating theory of reheating or preheating then needed to operate after inflationary era. Such theories prefer three legs bosonic decays φ→χχ, which doesn't have any analogy with standard model processes as much as I know. How...
Homework Statement
What initial mass of 23592U is required to operate a 350 MW reactor for 3 yrs? Assume 46% efficiency.
Homework Equations
I used Mass* C* efficiency as a decimal= power (e^-6) * time (in seconds)
and got 800 as the mass, however, this was incorrect
The Attempt at a...
Homework Statement
Assume that a 14 kg sample of 240Pu is used to produce electrical power from its α decay. If your device is 60% efficient in producing electrical power, how much power can be produced? (in watts)
Homework Equations
Q=mass of plutonium-mass alpha-mass daughter; 240 plutonium=...