Parity Definition and 200 Threads

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...

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...

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...

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...

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...

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...

Homework Statement How do you tell whether a differenital equation has well defined parity or not? The equation I have is: x3y'' + x2y' - x(x2+1)y=0 and it asks: "Does this equation have a well-defined parity? What does this imply for the solutions of the equation?" My instinct would be...

Homework Statement You are given in a earlier stage of this problem that the wavefunction is separable, ie.) \Psi(x,y) = X(x)Y(y) The problem asks you to solve for the wavefunction of a particle trapped in a 2D infinite square well using Parity. ie.) solve \Psi(-x,-y) = \Psi(x,y) and...

Hi, while reading the section about the parity operator from the QM book by Cohen-Tannoudji (complement F II, page 192), I found this: " Consider an arbitrary vector |\psi\rangle of \mathcal{E}_\vec{r} : |\psi\rangle = \int d^3 r \psi(\vec{r})|\vec{r} \rangle If the variable...

Homework Statement How does the wave function of spin 1/2 change under parity? Homework Equations The Attempt at a Solution The behavior of the eigenfunctions of orbital angular momentum L is easily seen from their explicit form, namely spherical function Yml is multiplied by...

Hi, very simple question: What is the parity of the anti neutral kaon?

[FONT="Arial"][SIZE="2"]Is there a proof or way of proving that all even numbers (taking into account the definition of an even number as n=2k) end in 0,2,4,6, or 8?

Hy... I'm reviewing some nuclear physics but don't remember certain topics. This exercise for example: Knowing that ^{9}_{4}Be^{5} and ^{9}_{5}B^{4} have both as quantum numbers \frac{3}{2}^{-} and their properties are determined by the odd nucleon, show that the ground state of...

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-)...

Im trying to understand parity in the Standard Model. Ive read that quarks have positive parity. However I thought that the reason electrons have negative parity is because of the a symmetry of their wave functions, and this is what defines them as fermions. Quarks are fermions as well as I...

I had read an article about the law of conservation of parity was disproved by a columbian physicist,Chien-Shiung Wu through experimental basis. My doubt is whether there was a flaw in the original theory of the law.If yes, then where was it?

Homework Statement The parity operator is defined as P \psi (x) = \psi (-x). Show that P and p_x anti-commute, that is, \{ P,p_x \} = Pp_x + p_xP = 0 . Homework Equations P \psi (x) = \psi (-x) p_x = - i \hbar \frac{\partial}{\partial x} The Attempt at a Solution \{ P,p_x \}...

Hi I know that stationary states in a system with an even potential energy function have to be either even or odd. Why does the ground state have to be even, and not odd? This is asserted in Griffiths, page 298.

Does Hawking radiation account for the parity imbalance between matter and anti-matter? Do Black Holes create matter? If a matter/anti-matter pair materializes on either side of the event horizon of a black hole: 1) if the matter particle is on the inside of the event horizon, the mass of the...

I would like to know how can parity be physically interpreted :confused:?