Parity Definition and 220 Threads

Hi, I am revising my intro to nuclear physics class and was wondering why is parity so important ? I mean OK, I get it, physicists are crazy about symmetries, but I do not understand what does it physically mean... I was wondering if someone could possibly talk me through its importance and...

A quark and antiquark have opposite parity. The quark is customarily taken to have positive parity. I understand this to mean that Pf = f, where f is the wavefunction of the quark and Pg = -g, where g is the wavefunction of the antiquark. Does this mean that P acting on an antiquark...

I am confused about when and to what extent parity is violated in weak decays. On the one hand, there's Wu's famous experiment where electrons are emitted preferentially in one direction. This parity violation can be said to be maximal, since all electrons are emitted in one direction...

Homework Statement I am confused about parity violation in weak decays. I learned about Wu's famous experiment and how it demonstrates that parity is violated in weak decays. However, when I am doing a course problem on nuclear β-decay, then it still necessary to conserve parity...

The parity operator has eigenvalues of +/- 1 and particles can have intrinsic parity of +/- 1. What does it matter? Does a P=-1 particle behave physically different from a P=+1 particle? Is parity a useful concept only in the sense that one can check if an interaction conserves parity (parity...

I just came across the following Quote in an introductory Quantum physics book"There are certain experiments in which behave differently in their mirror image form, this is called the Parity Violation in." Can anybody explain in detail what parity violation is and what mathematical description...

I don't understand how parity error detection is any use since if there are an even number of mistakes, the errors won't be detected. If there's more to it than this please let me know.

Im quite confused with the Parity idea. I never payed much attention to it. My thought always was that Parity is related to a discrete symetry of space and it is something that can be measured and can give 1 or -1 (like the x-momentum of a particle that can give "2" "1,9" "1,8" and so on)...

I am trying to understand how it can be shown that under parity transformation we have to have \hat{P} \hat{a}_{\mathbf{p},\lambda} \hat{P} = - \hat{a}_{-\mathbf{p},\lambda} , I mean the negative sign (negative intrinsic parity of photon). So I am trying to prove that from the vector nature of...

I'm currently reading about parity and it's role in QFT and I am trying to understand an argument of why parity exchanges right-handed and left-handed spinors. At page 94 in http://www.damtp.cam.ac.uk/user/tong/qft/four.pdf David Tong states that "Under parity, the left and...

Homework Statement I need to find the eigenvalues of the pion triplet under G parity Homework Equations G\mid\psi\rangle = CR_2\mid\psi\rangle The Attempt at a Solution OK so visually this problem is pretty simple, rotation about the 2 axis takes a pi+ to a pi- and then charge...

Homework Statement The problem is referring to an example in the chapter. Use Parity Arguments to show that in Example3-5 the A_n for n is even must vanish. Here is the example: http://imageshack.us/a/img28/5664/qmproblem.gif The Attempt at a Solution I honestly do not know where to start...

Hello, I'm wondering if there are any tricks to quickly determine the parity of the weight of a binary number, i.e., whether it's even or odd. I'm not interested at all in the actual weight of the number, but in the parity of it. I know that if say x = a XOR b, then x has odd weight iff...

I'm reading about selection rules, and the book is talking about how if you have a parity switching operator in between two wave vectors of opposite (definite) parity, the result is 0. For example, we have \left\langle2,0,0 \right|\hat{X}\left|2,0,0\right\rangle = 0 because...

While I was studying Ch 2.6 of Weinberg QFT vol I, I came to have some question about the conservation of parity and time reversal. In page 74 and 75 of Weinberg vol I, it says the fact that fundamental multiplication rule of the Poincare group is still valid even when we concerns improper...

hi, I'm studying parity violation in particle physics.. I have this decay: 1+ ---> 0+ + 0+ in J^P notation. Why this process violate parity? All terms have positive parity. The parity of the products is just (+1)*(+1)*(-1)^l, so this means that the two scalar particles...

Hi, I was going through the concept of R parity in SUSY. In the case of SUSY we do not have Baryon and Lepton number conservation instead we have R parity conservation defined by, R-parity= (-1)^2s+3B+L which is required for the proton to be stable. But it has been found that...

I am struggling with the concept of parity. I understand the analogies with spinning balls etc. and that the physics in the mirror should also be found in the world. I also understand that a wavefunction is an eigenfunction of parity if under the parity operator it looks the same. (indicating...

Homework Statement A particle of mass m moves in the potential energy V(x)= \frac{1}{2} mω2x2 . The ground-state wave function is \psi0(x)=(\frac{a}{π})1/4e-ax2/2 and the first excited-state wave function is \psi1(x)=(\frac{4a^3}{π})1/4e-ax2/2 where a = mω/\hbar What is the average value of...

All the proofs I have seen for this theorem uses the same argument: First prove that the identity permutation has even parity. Then let a be (one of) the first elements to appear in a transposition representation of a permutation in Sn. Then identify all the other transpositions in the...

Hi guys, I'm reading Shankar and he's talking about the Variational method for approximating wave functions and energy levels. At one point he's using the example V(x) = λx^4, which is obviously an even function. He says "because H is parity invariant, the states will occur with alternating...

Homework Statement Find spin, parity and isospin of second excited state of {}^{10}B nucleus, if we know that the second excited state (at E_x=1.74 MeV) can intensively be excited with reactions: {}^{7}Li(\alpha,\ n),\ {}^{9}Be(d,\ n),\ {}^{9}Be({}^{3}He,\ d), {}^{11}B(p,\ d), and cannot be...

Homework Statement I have an element: {}^{207}Pb, with Z=82, and A=125, and I need to find spin and parity of it.Homework Equations The angular momentum is determined by the angular momentum of the last nucleon that is odd, in this case it will be one unpaired neutron. Now what confuses me is...

Can someone explain in easy to understand terms, what parity violation is? specifically: "Only the left-handed components of particles and right-handed components of antiparticles participate in weak interactions in the standard model." Thanks in advance.BONUS: if you're like a particle...

Hello , Homework Statement I'm supposed to find restrictions for the spin and parity of the Kaon from the the following decay : K^0 \rightarrow \pi^0 \pi^0 Homework Equations The only thing I know is that \pi^0 spin-parity is 0^- The Attempt at a Solution I said that the spin of the...

Homework Statement The wavefunction describing state of a system is, \psi (r,\theta ,\phi )=\frac{1}{8\sqrt{\pi }}\left( \frac{1}{a_{0}}% \right) ^{3/2}\frac{r}{a_{0}}e^{-4/2a_{0}}\sin \theta e^{-i\phi } Find the parity of system in this state. The Attempt at a Solution \psi...

I am trying to understand the following which is proving difficult: It is found that (and the proof here is clear) [P, Jj] anticommutes with Vi Where P = parity operator Jj and Vi are the j th and i th components of the angular momentum vector and an arbitrary vector respectively...

Homework Statement What is the shell model spin and parity of _{38}^{89}Sr? 2. The attempt at a solution If i fill the levels as we usually do, Protons will end up in the level 1f_{5/2} with 6protons,ie the level is completely filled If the neutron number is considered,1g_{7/2}...

QM says that states which are simultaneous eigenstates of two commuting observables are allowed. If you don't have such states to start with you can construct them with the Gramm-Schmidt orthogonalization procedure. Consider the excited states of a nucleus. (They can be considered eigenstates...

Homework Statement How do I determine the parity of a permutation? I think my reasoning may be faulty. By a theorem, an n-cycle is the product of (n-1) transpositions. For example, a 5 cycle can be written as 4 transpositions. Now say I have a permutation written in cycle notation: (1...

Hi! Does anyone know how Wigner D-matrices transform under parity? Is it something like D^j_{m m'} (\pi - \theta, \phi + \pi) = (-1)^{j +m-m'} D^j_{m m'}(\theta, \phi)?

Homework Statement Show that the parity operation (reflection through the origin) on a point (\rho, \varphi, z) relative to fixed (x, y, z) axes consists of the transformation: \rho \to \rho \varphi \to \varphi \pm \pi z \to -z Also, show that the unit vectors of the cylindrical polar...

Homework Statement A particle is of mass m has the wave function \psi(x)=Ne-k|x-a| with (a>0): The particle is in the state \psi, and its parity is measured. What is the probability to find a positive parity? Homework Equations None that I can think of... The Attempt at a...

Dear Friends, I'm would like know classic problems about parity property, in other hand, classic problems that has in your solutions, in any way, issues about parity. I want investigate issues about the use of parity in distributed algorithms. Anybody can help me? Thank's.. Nulll

Hi, I understand that anti-particles have the opposite charge to particles. Do anti-particles have the opposite parity to particles as well? John

Deuteron is given by j(p)=1(+) In my textbook it says that the observed parity of + for deuteron means that the orbital angular momentum quantum number, l, is even so is 0 or 2, and s=1. However, looking back the textbook also says that for odd-odd nuclei, the parity is given by the...

Why is j=0 to j'=0 forbidden by the parity rule if spin orbit interaction is significant?

I'm struggling with the relation between particle exchange and parity with the case of para- and ortho-hydrogen. The overall wavefunction must be antisymmetric with respect to particle exchange and so for para-hydrogen (an antisymmetric spin state) the spatial part of the wavefunction must be...

I have read about Wu et al. and their experiments with Co 60 that showed that the weak interaction violates parity. I don't quite get it tho. 6 So they aligned Co atoms in a magnetic field. Some of the nuclei decay and emit neutrinos and electrons. It was observed that an equal number of the...

Hi folks. I was always under the impression that the 'good quantum numbers' that we use to classify a particle species were always the eigenvalues of operators that commute with Hamiltonian governing that species. But it just struck me that weakly interacting particles have definite parity...

This APS page http://focus.aps.org/story/v22/st19 describes the classic experiment by Wu et al. in the 50's that demonstrated parity violation. It contains the following explanation: "[1] The magnetism of the nuclei can be thought of as resulting from their spin. With the nuclei aligned with...

1. Use the shell model to predict the nuclear parity and range of possible values for nuclear spin for 14N, 20F, 24Na and 26Al. Compare witht he actual parities and spin 2. J = Jn + Jp pi = (-1)^l The Attempt at a Solution I've done out all of them, I got the theoretical values...

Homework Statement What is the parity and possible spins predicted by the single particle shell model for the ground state of the 19K40 nucleus (I'm most unsure about the spins) Homework Equations The Attempt at a Solution This has 19 protons and 21 neutrons. Odd-odd...

Hi everyone I was wondering how to determine the parity of a function of multiple variables. Say the function is: f(x,z) = xz How would I determine its parity? For the above function it is true that #1 f(x,z) = f(-x,-z) but its also true that #2 \int_{-a}^{a}\int_{-a}^{a}xz \dx...

Hi, I know that the angular momentum eigenfunctions in spherical coordinates are spherical harmonics, Ylm ( \theta, \phi ) \propto (-1)mPlm(cos\theta)eim\phi. Applying the parity operator to Ylm ( \theta,\phi ) means that \theta -> \pi - \theta and \phi -> \phi +\pi. This implies that...

Homework Statement Given that, for operators A and B: \mathrm{e}^{\mathrm{i} \alpha A} B \mathrm{e}^{-\mathrm{i} \alpha A} = \sum_{n=0}^{\infinity} {(\mathrm{i}\alpha)^n \over n!} B_n where B_0 = B and B_n = [A, B_{n-1}] for n=1,2,... show that: P_1...

I'm unsure about how parity is used or indeed what it actually is in quantum mechanics. If someone could shed some light on this it'd be a great help.

I'm trying to get my head around the cobalt-60 beta decay experiment that apparently was used to show the weak decay did not conserve parity. It basically has a bunch of cobalt nuclei at low temperature in a magnetic field so that their spins are all aligned parallel to the field. The experiment...

Hello all, This is something that has irked me for a while. The Li/Yang/Wu beta decay showed parity violation in the weak force, but from what I gather, it was the helicities of the electrons they measured, while it is the chiral states which are important. For a massive fermion, aren't the...

I am trying to work out the wavefunctions for a particle in a box between -a/2 and a/2.I have already gone through the solution for a box between 0 and a and got the solution \sqrt{\frac{2}{a}}sin(\frac{n\pi x}{a} )So I can see that for -a/2 to a/2 I have...