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3
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0answers
58 views

Parity invariance of Einstein-Hilbert Lagrangian

How can we show that the Einstein-Hilbert action is Parity invariant? $$ S_{EH}=\int \sqrt{-g}R d^4x $$
2
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1answer
86 views

parity invariance of Einstein, Maxwell and Dirac Lagrangians

How can we show that Einstein, Maxwell and Dirac Lagrangians are parity invariant?
3
votes
2answers
67 views

Higgs Standard Model Parity

In the Standard Model, the Higgs boson is expected to have spin 0 and even parity. I know how to get the spin-0 approach, but how do I argue for the even parity? Could you give a simple and a more ...
6
votes
1answer
78 views

Parity on gamma matrices

I want to understand clearly why $ P \gamma^{\mu} P = \gamma^{\mu} $, where $ P $ is the parity operator. This result follow for example from pag. 66 of Peskin-Schroeder. The parity operator acts ...
2
votes
2answers
54 views

Why is this not a violation of parity invarance for EM

I read that Wu's experiment illustrates that parity violation is possible for weak processes. In that experiment, when Co-60 undergoes beta decay, the emitted electrons come out opposite to the ...
3
votes
1answer
113 views

What is the parity of a $W^{-}$ boson?

What is the parity eigenvalue of the $W^{\pm}$ boson, or is it even an eigenstate? I have not found any source that discusses this. I have seen some lists of particles with their parity eigenvalues, ...
2
votes
1answer
47 views

Dipole matrix elements through parity argument

I am trying to find the following dipole moment matrix element $(|n,\ell,m\rangle)$. $$e\langle1,0,0|\vec r|2,0,0\rangle$$ I believe that I can say this matrix element is zero because of parity. The ...
0
votes
1answer
85 views

Finding the odd parity bound state wave function for a particle in one dimension

Let a particle of mass $m$ and energy $E$ be moving on the $x$-axis in a potential $V(x)$ given by $$V(x)=\left\{\begin{matrix} -V_{0}, & -a<x<a\\ 0, & otherwise \end{matrix}\right.$$ ...
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0answers
55 views

Angular momentums addition in QM

We know that the spatial inversion parity for eigenfunctions of $\hat {L}_{z}$ operator (spherical functions) is $(-1)^{l}$, where $l$ refers to angular momentum. So for product of two eigenfunctions ...
4
votes
1answer
166 views

What parity has an electron?

I couldn't find anything about the parity of an electron. Neither in the german, nor in the spanish and nor in the english version of Wikipedia. I only found one sentence in the parity article of ...
2
votes
1answer
62 views

What are “parity considerations” in deciding the form of the Hamiltonian?

In "introductory Quantum Optics", by Gerry and Knight, the Jeynes model is considered. In this model of electron-EM field interaction the electron is approximated by a two state system ($\lvert ...
2
votes
0answers
67 views

The proof that Dirac's hamiltonian commutes with inversion operator

I tried to check the statement that Dirac free Hamiltonian commutes with inversion operator. For $$ \hat {P}\Psi(\mathbf r , t) = i\hat {\gamma}_{0}\Psi (-\mathbf r , t), \quad \hat {H} = (\hat ...
2
votes
1answer
48 views

Is this process possible for L=0? $e^+e^- \to 2\eta_c$

For the following $$e^+ e^- \to \eta_c \eta_c$$ I think it violates parity conservation so it can't happen, but is there any other reason as to why it can't take place? Or is it actually possible?
2
votes
1answer
128 views

Intrinsic parity of particle and antiparticle with spin zero

I need to prove that the intrinsic parities of a particle and antiparticle with spin zero are the same. Can I prove that by an argument that operator of $P$-inversion commutes with charge conjugation ...
2
votes
1answer
165 views

Parity of proton is 1?

I have found from Wikipedia that "a parity transformation is the flip in the sign of spatial coordinates". Now when we operate parity operator, does that mean we are taking any physical entity at ...
2
votes
1answer
262 views

Parity transformation for spinors (pinors) in odd spacetime dimensions

What is the transformation law for spinors (pinors) under parity in an odd number of spacetime dimensions? I know how to derive the transformation properties of spinors (pinors) under parity in an ...
2
votes
1answer
43 views

Implementing a transformation as $UaU$ and not $UaU^{-1}$?

I know one associates to each symmetry transformation a unitary/antiunitary operater...etc. But equation 3.123 in Peskin and Schroeder (PS) says that parity is implemented as $(\mathbf{p}$ is the ...
8
votes
1answer
117 views

Complex Representation of a gauge group and a Chiral Gauge Theory

In this John Preskill et al paper, a statement is made in page 1: We will refer to a gauge theory with fermions transforming as a complex representation of the gauge group as a chiral gauge ...
4
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0answers
141 views

Action of Parity operator on Impulse representation

Is my derivation of the action of the parity operator $\mathbb{P}$ on the $|p\rangle$ representation correct? $$\left( \mathbb{P}\tilde\psi \right)(p)= - \tilde\psi (p).$$ Obtained from $$\left( ...
2
votes
1answer
180 views

Lorentz group representation and transformation of “vectors”

Let $P$ be the parity operator of the Lorentz group, $$P=\begin{pmatrix}1&0&0&0\\0&-1&0&0\\0&0&-1&0\\0&0&0&-1\end{pmatrix}$$ the commutation relations ...
3
votes
1answer
67 views

Fourier Expansions for Closed Strings and Parity

I'm revising some string basics, and have come across the following problem. For closed strings one introduces the worldsheet parity operator $$\Pi : \sigma \mapsto \ell-\sigma$$ where $\ell$ is the ...
2
votes
0answers
24 views

What were the immediate consequences Yang-Lee work on Weak Interaction?

I am studying the history of Modern Physics and Yang-Lee earned their Nobel the next year after the Cobalt experiments. I am familiar with the chronology, but am not clear what those findings meant to ...
3
votes
2answers
174 views

C, T, P transformation mistakes in ``Peskin&Schroeder's QFT''?

I suppose the right way to do C (charge), T (time reversal), P(parity) transformation on the state $\hat{O}| v \rangle$ with operators $\hat{O}$ is that: $$ C(\hat{O}| v \rangle)=(C\hat{O}C^{-1})(C| ...
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vote
2answers
410 views

Bound state in a potential well?

Reading from http://quantummechanics.ucsd.edu/ph130a/130_notes/node151.html It says: This means that the solutions separate into even parity and odd parity states. We could have guessed this from ...
9
votes
1answer
483 views

How are anyons possible?

If $|ψ\rangle$ is the state of a system of two indistinguishable particles, then we have an exchange operator P which switches the states of the two particles. Since the two particles are ...
0
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2answers
340 views

A few parity questions for simple harmonic oscillator

I think I understand that the solution to the Schrodinger equation for the SHO is based on the Hermite polynomials (and the Guassian function). The solution set of all even Hermite polynomials are a ...
1
vote
1answer
194 views

Time reversal and parity symmetry

I was previously under the misapprehension that time $T$ and parity $P$ symmetries in conjunction ($PT$) were a reflection in $(3+1)$-dimensional space-time, where $$P: \vec x \to -\vec x$$ $$T: t ...
-6
votes
1answer
187 views

Has the spin and parity of the Higgs boson been experimentally confirmed? [closed]

I read in a newspaper that the Higgs boson might be the new boson but that this was not confirmed, because we don't know its properties, e.g. its spin or parity. Now I see it confirmed that it is the ...
4
votes
1answer
220 views

How to derive the form of the parity operator acting on Lorentz spinors?

I'm reading Berestetskii (Volume 4 of Landau & Lifshitz) section 19 on inversion of spinors. Berestetskii says parity $P$ maps undotted spinors into dotted spinors and vice-versa as ...
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vote
0answers
94 views

Parity of the surface state in a Topological Insulator (TI)?

Please bear with this experimentalist trying to understand the subtleties of TIs in what may well be imprecise language. I appreciate that one can deduce the topological trivial or non-trivial nature ...
0
votes
1answer
918 views

Nuclear reactions conservation laws

I'd want to know the basic rules to apply the conservation laws in nuclear reactions (nuclear fusion, nuclear fission, radioactive decays, etc.) to determine parity and angular momentum of the ...
17
votes
1answer
325 views

Why are pear-shaped nuclei possible?

In a recent question, Ben Crowell raised an observation which really puzzled me. I obtained a partial answer by looking in the literature, but I would like to know if it's on the right track, and a ...
3
votes
1answer
202 views

Weak interaction and the Chirality of anti-particles

Consider a weak current of the form $ J^{\mu} = \bar{u}_{\nu}\gamma^{\mu}(1-\gamma^5)u_{e} $ This describes the part of a weak process where a left-handed electron converts into a left-handed ...
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0answers
47 views

Can we build spinorial eigenstates of Time reversal symmetry?

In the SM, and general theories with spinors, we can build the Parity left/right eigenspinors. Indeed, there are also ELKO fields, eigenstates of Charge operator (non-standard Wigner classes). Can we ...
1
vote
1answer
141 views

spin parity $J^P$ notation

In particle physics, when you read $J^P$, does it mean Spin parity or total angular momentum parity? I know that the letter $J$ is used for TOTAL angular momentum but I think I read somewhere that ...
1
vote
2answers
548 views

Total Angular Momentum of deuteron

I'm studying for my nuclear physics exam and the book we use is Introductory Nuclear Physics by K.S. Krane. In the chapter on Basic Nuclear Structure, we research the deuteron. However, when ...
1
vote
1answer
281 views

Parity and Particle Exchange Operators

I would be grateful if somebody could help me brining the parity operator and the particle exchange operator together. Suppose, there is a two-proton system, where one proton is sitting at $+r$ on ...
4
votes
1answer
122 views

Parity of a decay

If a particle of unknown intrinsic parity decays into 2 particles each with negative intrinsic parity, does that necessarily imply that the original particle also has negative parity?
3
votes
1answer
510 views

Even and Odd States of a 1D finite potential well

Is it possible for a particle trapped in a 1D finite potential well to evolve from a even state to an odd state and vice-versa? Why?
3
votes
0answers
187 views

Pseudo scalar mass and Pure scalar mass

Since the only difference between pseudo scalar and a scalar term is just a change of sign under a parity inversion, is it possible that both of them be present in the same field and interact? For ...
5
votes
0answers
193 views

Parity and Helicity of the Higgs Boson

I have been studying how the spin and parity of the new boson discovered at the LHC will be studied and have run into some confusion. The Standard Model Higgs is expected to be a scalar (i.e. have ...
2
votes
2answers
159 views

Parity, how many dimensions to switch?

Parity is described in Wikipedia as flipping of one dimension, or - in the special case of three dimensional physics - as flipping all of them. Is there any simple rule that generalises both for any ...
5
votes
1answer
644 views

Is 4-volume element a scalar or a pseudoscalar in special relativity?

In general relativity 4-volume element $\mathrm{d}^4 x = \mathrm{d} x^0\mathrm{d} x^1 \mathrm{d} x^2\mathrm{d} x^3$ is clearly a pseudoscalar (or scalar density) of weight 1 since it transforms as ...
3
votes
1answer
449 views

Strong Decay and Parity Conservation?

The following decay is possible according to the PDG and according to my notes it is a strong decay: $$\omega(1420) \to \rho^0 + \pi^0$$ The JPC values are: $\omega(1420)$ 1-- $\rho$ ...
0
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4answers
323 views

Would a person not be able to distinguish left from right in outer space?

Is it true that human in outer space can't differ right side and left side, with no other objects for reference?
13
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2answers
3k views

Definite Parity of Solutions to a Schrödinger Equation with even Potential?

I am reading up on the Schrödinger equation and I quote: Because the potential is symmetric under $x\to-x$, we expect that there will be solutions of definite parity. Could someone kindly ...
9
votes
2answers
451 views

The Ozma Problem

The "Ozma problem" was coined by Martin Gardner in his book "The Ambidextrous Universe", based on Project Ozma. Gardner claims that the problem of explaining the humans left-right convention would ...
4
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1answer
348 views

Why does parity violation in weak decay imply decay asymmetry?

I googled the sentence in the title of this question and found the famous experiment by Wu et al demonstrating that electrons in weak decay are emitted ``in the direction of motion of a left-handed ...
4
votes
1answer
336 views

Weak equivalence principle tests

on the wikipedia article about the equivalence principle there is a mention about testing the EP against parity-violating masses; "The equivalence principle is untested against opposite ...
5
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1answer
1k views

Why does lambda decay violate parity?

When a lambda particle decays into proton and a pion, I am told it does not conserve parity. Why?