Weak Definition and 473 Threads

Hi, I'm developing a new bio reactor, which in this instance you can think of as just a perspex fish tank. But have come across an unusual requirement to apply a roughly 0.01T magnetic field across the volume of the tank with mainly water in it. No position in the tank can be less than 0.08T and...

I teach soil mechanics and I introduce to my students brittle and ductile materials. Failure of brittle materials is obvious for them but not for ductile materials. Do you know any ductile material that can be easily broken by traction? Unfortunately I do not have any tensile testing machine so...

Hello In Newtonian theory Poisson's equation holds: ## \nabla ^{2} U = 4 \pi G \rho ##. So: given a density ##\rho ##, it is possible to find a potential U. On the other hand, I can choose a random function U and give it a gravitational significance if it gives, by Poisson's eq., a density...

Homework Statement I'm having a bit of trouble evaluating the following commutator $$ \left[T^{+},T^{-}\right] $$ where T^{+}=\int_{M}d^{3}x\:\bar{\nu}_{L}\gamma^{0}e_{L}=\int_{M}d^{3}x\:\nu_{L}^{\dagger}e_{L} and...

Hello all, I'm curious about Electro Weak relationship. I differentiate between mechanism and mathematics, with the equilibrium falling heavily to the left. Good with the former, weaker with the latter. Anybody aware of relevant philosophy/findings? Thanks much. Jim

Homework Statement If enough of a monoprotic acid is dissolved in water to produce a 0.0153 M solution with a pH of 6.31, what is the equilibrium constant, Ka, for the reaction? Homework EquationsThe Attempt at a Solution I have attempted to solve this problem using ICE tables, but keep getting...

Are there any particles which have a neutral electrical charge and are not affected by the weak or strong nuclear force? Thank you for your time and please excuse me if I'm being very ignorant!

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

All physicists I've heard discussing gravity to the public always mentions that it's a very weak force compared to the other forces and that no one knows why. One possible reason could be that the gravitational force is propagating in other dimensions. As far as I know gravity works in a...

Homework Statement Which side does the equilibrium favour? Homework Equations Equilibrium favours weak acid or weak base (I don't know why :frown:) The Attempt at a Solution Using the given pka values, since the reactant is the weaker acid, reactants are favoured. (Backward reaction is...

There is confusion in my mind regarding Weak forces

How can I derive the running coupling for the weak interaction. I have found derivations for QED and QCD that involve the β function http://www.physics.umd.edu/courses/Phys741/xji/chapter1.pdf but I can't find anything specific for the WI. Thanks.

In 2012, experimenters showed that when two entangled photons separate and when one goes through the double slit, we can tell which slit it went through and see that they still created an interference pattern because the photon that it was entangled to tells us which slit it went through. What...

<<Mentor note: Moved from other thread.>> I have 4 questions: 1. Why Weinberg angle affects neutral boson mixing, while W+ and W- are unaffected? 2. Is there any relation between Weinberg angle and CP violation angle? Are they absolutely independent? 3. How our world would be different if...

Why am I able to repel two liked poles magnet despite the presence of Earth gravity? The Earth gravity is able to hold skyscrapers together but yet unable to prevent two magnets from repelling? I know there is an explanation that says that unlike graviton, all the other fundamental forces are...

So - this may sound like an easily answered question - but with push-back on my part I hope I can get to the real crux of what I'm asking, in any replies you might be kind enough to provide. I hope the answer is not, eventually, simple. The crux of my issue is this: Why do we believe gravity...

Schrödinger equation for N-particles is: U_{System Potential Energy}(r_1,r_2,r_3,...,r_n,t)-\sum_{n=1}^{n_{max}}(\sum_{d=0}^{d_{max}}(\frac{d^2Ψ(r_1,r_2,r_3,...,r_n,t)}{dx_n^2})*\frac{ħ^2}{m_n})=i*ħ \frac{dΨ(r_1,r_2,r_3,...,r_n,t)}{dt} Where \sum_{d=0}^{d_{max}} is summation over dimensions...

In weak field regime i know that it is possible to quantize the gravitational field obtaining a quantum theory of free particles, called gravitons, which is very similar to the one for the electtromagnetic field. Do you know some book in wiich i can study this theory? In anycase what is the...

When we start by postulating local SU(2) gauge invariance for our weak isospin doublets \begin{align} \psi &= \begin{pmatrix} \nu_{e} \\ e^{-} \end{pmatrix}_{L} \end{align} etc., we have to introduce massless gauge fields to preserve the Lagrangian's invariance. For SU(2) this demands 3...

Hi There! i am little bit confused in between existence of strong and weak nuclear force, can someone please explain about these forces and about their existence

What is the entropy of weak and strong force? Can we determine their entropy? If so, I would like to know the formula of determining this. Thanks:wink:

I am really confused about it.Suppose we add 5 moles of acetic acid in 1 litre of water..The molarity of solution will be -(5 moles)/volume of solution?Or it will be -(the number of moles of acetic acid dissociated/dissolved)/volume of solution

Hi there, so my question is as follows. I understand that only the weak interaction can change the flavour of a quark, but why? Idea 1: It's due to the change in flavour also meaning a change in mass, thus a massive exchange particle is needed (gravity is negligible so forget the massive...

I am trying to get a better understaning of the pH of a solution containing a salt of a weak base and a salt of a weak acid. I know it depends on which equlibrium constant is greater but I am thinking more of what it is that actually happens. For example let say we have a solution containing...

Hello, everyone! I have a short question. I think everybody knows the Furry theorem for QED, which tells, in particular, that fermion loops with odd number of fermions always give 0. Does the same true for QCD of weak theory? Can one have non-zero contribution to 3-gluon vertex (or 3-boson...

Could someone please help me to understand the difference between the concepts of Weak Isospin, Chirality and Helicity. In particular, I have the following questions to which I was unable to find answers so far: 1. Since both spin direction and momentum are vectors, would not their apparent...

Today i was just randomly browsing the internet. Then i found this image: What if gravity is not the weakest fundamental force at all? Like the picture above if we remove the space among all atoms the Earth will occupy relatively a very small space. Then we know the gravity of that tiny...

Does anyone know any good introduction to V-A weak interaction theory?

I'm looking at Carroll's lecture notes 1997, intro to GR. Equation 7.27 which is that he's argued the S metric up to the form ##ds^{2}=-(1+\frac{\mu}{r})dt^{2}+(1+\frac{\mu}{r})^{-1}dr^{2}+r^{2}d\Omega^{2}## And argues that we expect to recover the weak limit as ##r \to \infty##. So he then...

Assume we have a free-falling particle in gravity in a static metric. Its worldline is described by: g_{\mu \nu} = \eta_{\mu \nu} + h_{\mu \nu} where ##|h_{\mu \nu} << 1|##. Taken from Hobson's book: Why did they let ##g^{k\mu} = \eta^{k\mu}##?

Comparing two sources one has ##\frac{d^{2}x^{i}}{dt^{2}}=-\frac{1}{2}\epsilon\bigtriangledown_{i}h_{00} ## and the other has ##\frac{d^{2}d^{i}}{dt^{2}}=\frac{1}{2}\epsilon\bigtriangledown^{i}h^{00}##, And the one using the lower index has the Newton-Poisson equation as ##...

http://www.mth.uct.ac.za/omei/gr/chap7/node3.html Shouldn't eq 45 have a minus sign, looking at eq 29. Although I'm confused because the positive sign makes sense when comparing with the Newton-Poisson equation. I can't see a sign error in eq 29. (I believe the metric signature here is...

The weak field approximation in the Newtonian limit shows that the coordinate acceleration along a geodesic is related to the gravitational force. The geodesic deviation equation relates the coordinate acceleration between adjacent geodesics to tidal forces. If I drop 2 balls together from the...

I have a question about magnetic repulsion. Suppose I have a permanent magnet (axially magnetized) placed on top of the iron core of an electromagnet. I want to switch on the elctromagnet to repel the permanent magnet. (Please assume the permanent magnet is contained in some kind of tube that...

I have the expression ##g_{ab}=\eta_{ab}+\epsilon h_{ab}##, The indices on ##h^{ab}## are raised with ##\eta^{ab}## to give ##g^{ab}=\eta^{ab}-\epsilon h^{ab}## I am not seeing where the minus sign comes from. So I know ##\eta^{ab}\eta_{bc}=\delta^{a}_{c}## and...

My textbook says: One of the decays occurs via a ## b \to c ## quark transition and is 'colour-allowed'.(Left of diagram). The other decay has a of ## b \to c ## and is 'colour-suppressed'.(Right of diagram) I'm unsure of what is meant by these terms, it doesn't really explain. I've...

Homework Statement What is the likely identity of a weak acid if a 0.50 mol/L solution of the acid has a pH of 3.18? Homework Equations HA + H2O <=> H3O + A K_{a} = \frac{[P]}{[R]} [H3O] = 10^{-pH} The Attempt at a Solution [/B] I set up an ICE table with the concentration given...

Hello, I've been reading a book on particle physics for the general audience, and as you might expect, I was left with a slew of nagging unanswered questions. There was a chapter on gauge symmetry where the author described that the weak and the EM forces are the same force at some energy...

My book says in the slow motion approx, so ## v << c ##, ##v=\frac{dx^{i}}{dt}=O(\epsilon) ## It then states: i) ##\frac{dx^{i}}{ds}=\frac{dt}{ds}\frac{dx^{i}}{dt}=O(\epsilon) ## ii) ## \frac{dx^{0}}{ds}=\frac{dt}{ds}=1+O(\epsilon) ## The geodesic equation reduces from...

Hey guys, So I have a question about the gauge invariance of the weak field approximation. So if I write the approximation as \Box h^{\mu\nu} -\partial_{\alpha}(\partial^{\mu}h^{\nu\alpha}+\partial^{\nu}h^{\mu\alpha})+\partial^{\mu}\partial^{\nu}h=0 then this is invariant under the gauge...

Hi all, I am a final year maths student and am doing my dissertation in the finite element method. I have gotten a little stuck with some parts though. I have the weak form as a(u,v)=l(v) where: $$a(u,v)=\int_{\Omega}(\bigtriangledown u \cdot\bigtriangledown v)$$ and $$l(v)=\int_\Omega...

Hello PhysicsForums! I am a Physics/Math double major undergraduate junior. I've always loved math, and to study the universe; so I decided to combine both and become a physicist! I did my Gen Phys 1-2 (with Calc) and most of my math at a state college and then I transferred to a university...

Is the weak nuclear force really a force? How can an electron be ejected from a nucleus which has many protons; wouldn't positive charges hold it back?

I have the weak form of the poisson equation as $a(u,v)=l(v)$ where $$a(u,v)=\int_\Omega \bigtriangledown u\cdot\bigtriangledown v$$ I have been proving existence and uniqueness of the solution using the Lax-Milgram Thm. I am stuck on proving that the bilinear form $$a(u,v)$$ is coercive. I...

For example: $$ y^{2} = 25- x^{2} $$ $$ y = \sqrt{25- x^{2}} , -5\leq x\leq 5 $$ This part: $$ , -5\leq x\leq 5 $$ What is the name of this?If it were a function, it would be the domain. And for equations, and resolutions of equations, what is the name? Other example, the equation: xy = 1...

Consider a Maximal (negatively) charged black hole. Can it have "flavor" or weak charge? Suppose a muon collided with that hole. Would an electron be emitted? What if electron neutrinos collided with that black hole; would electron neutrinos more likely be emitted as Hawking Radiation...

Hi all - in the question below I could do with some help on the "..explanation for the relative strengths..." bit, as I can't think of anything to say. 1. Homework Statement Compare and contrast the properties of the strong and weak interactions. Include in your account an explanation for the...

I was wondering. For fermions someone can find that the Lorentz group is isomorphic to SU_L(2) \times SU_R(2) . However in the Standard Model there is only left-handed neutrinos interacting with the rest of matter. If Lorentz was not partially violated, wouldn't someone expect for the left and...

Homework Statement The question asks me to use the modified Arrhenius theory of acids to classify the following as strong or weak acids, HNO3(aq), HI(aq) and HF(aq). Homework Equations But the book only says that the modified Arrhenius theory for acids is, "an Arrhenius acid reacts with...

I can't understand completely the concept of strong nuclear force and weak nuclear force,,,