Particle Definition and 1000 Threads

http://arxiv.org/abs/1612.03825 Towards a new paradigm for quark-lepton unification Christopher Smith (Submitted on 12 Dec 2016) My comments: This is my favorite. It is a modification of Minimal Flavor Violation (MFV), a popular philosophy which posits that any BSM couplings may only involve...

Homework Statement You have two samples of the same gas in the same size container, with the same pressure. The gas in the first container has a kelvin temperature four times that of the gas in the other container. The ratio of number of collisions with the wall in the first container compared...

I'm a Nuclear Physics student and I'm finishing the university in this period. I was searching for a PhD in Particle Physics but I don't know where to go, anyone knows some interesting school to make an application? Thanks

...becoming infinite at rest, doesn't that mean it has infinite mass whatever velocity it has? How could that quasiparticle be at rest to achieve infinite mass?

Homework Statement an alpha particle with a charge of 2e is fixed at the origin. a proton is aimed at the alpha particle and shot from a distance of 2.00 m at a speed of 3.46x10^6 m/s. How close will the proton come to the alpha particle before coming to a stop? Homework Equations Please help...

Homework Statement Find the force exerted on a particle on the Earth by the sun. Homework Equations F = - GMm/r2 r = distance between sun and particle M = mass of sun G = Gravitational constant m = ? The Attempt at a Solution Should I be using the other mass as that of the earth, or that of...

Homework Statement A 2 GeV electron is incident on proton (m_p * C^2 = 0.938 GeV) target at rest. Calculate the invariant mass of the electron-proton pair in the Center of Mass(CM) frame. Neglect the mass of electron which is much less than the proton mass.Homework Equations M = [P1 + P2)][/2]...

Lagrangians that include a particle field and its corresponding antiparticle field always have the particle field and the antiparticle field in the same terms. For example, in the theory of a complex scalar boson ##\phi##, the Lagrangian is a function of ##\phi^{*}\phi##, and not of ##\phi##...

College-level introductory physics textbooks usually devote a chapter to special relativity. Peter J. Riggs in his article appearing in the February 2016 issue of The Physics Teacher (pp 80-82) derives a couple of expressions for the kinetic energy of a massive (as opposed to massless) particle...

Hi all, This is a followup to a question I asked a number of years ago about the Unruh effect. I understand that an accelerated observer will see warm gas of particles following a blackbody distribution with some temperature T, where as an inertial observer would see none. My question is: how...

According to quantum theory it is possible for a particle to diffract around a barrier. Does this explain why I often seem to completely miss a tennis ball? Explain why or why not?

Hi there, in electrospinning, a positive charge of around 10.000Volt is applied to a needle, where a viscous polymer is extruded. There is a grounded collector in a distance of 15mm and the established electrical field generates electrostatic forces and draws a thin polymer jet to the...

I believe I understand how the Higgs field imparts "mass" on a particle. Would someone explain how the existence of the Higgs Field means there has to be a Higgs Particle?

Hello folks. What math do I need to understand books talking about quark-antiquark pairs, the Higgs field, and the Standard Model?

Hi, Are there any fundamental "particles" that has no charge (e.g. color charge, electric charge, etc.), mass, volume and spin?

Can anyone help me find any mistake in this expansion ? (I've asked it also in other places but I got no answer)) Pα= e Fαβ Uβ c = speed of light m = "rest" mass e = charge a = sqr(1 - v2/c2) v2 = vx2 + vy2 + vz2 dτ = dt a (proper time) momentum 4 vector : Pα = [mc/a , mvx/a , mvy/a ...

Homework Statement A particle of mass 5.0kg travels initially with a velocity of 8.0m/sˆı and then interacts with a particle of mass 6.0kg which was initially at rest. After the interaction the 5.0kg mass travels at a speed of 4.0m along a direction which makes an angle of 53◦ with the x-axis...

How does a particles symmetry effect the way it behaves? Do particles with similar symmetry interact with each other in a special way than 2 particles with different symmetries?

Homework Statement An initial particle distribution n(r, t) is distributed along an infinite line along the z-axis in a coordinate system. The particle distribution is let go and spreads out from this line. a) How likely is it to find a particle on a circle with distance r from the z-axis at...

Homework Statement [/B]Homework Equations F= qvbThe Attempt at a Solution [/B] I tried FTTT and FTFT but both were wrong , i know that the acceleration is in the same direction as the force , but how come the other 3 are not all true.By the right hand rule shouldn't the force be...

Homework Statement Homework Equations F= q v x B The Attempt at a Solution [/B] I tried using the right hand rule to find the direction of the force and seeing if the particle curves that way or not but obviously that's wrong

How is it possible that a point like particle is 0 dimensional? Could it only exist within pure mathematics? or actually exist physically in our universe?

I know that, in the presence of a magnetic field, the momentum of a charge particle changes from ##p_{i}## to ##\pi_{i}\equiv p_{i}+eA_{i}##, where ##e## is the charge of the particle. I was wondering if this definition of momentum is gauge-invariant? How about ##\tilde{\pi}_{i}=p_{i}-eA_{i}##?

Homework Statement Show that for the case of a general inhomogeneous magnetic field, $$\dot{\vec{v}}=\frac{e}{2mc} (\vec{v} \times \vec{B} - \vec{B} \times {v})$$ The attempt at a solution I think I am oversimplifying things. I used that, for an electron in a magnetic field, m \frac{d...

Is it more probable that particles will collide if both are moving or if one has velocity equal to 0? Let's say we don't have any forces between them and they're on a closed surface (for example a square).

Homework Statement A particle is in the n = 1 state of an infinite square well of size L. T. What is the probability to find the particle in the region Δx = 0.007L at the point x = L/2? 3L/4? (Since Δx is small you don't need to do any integration) Homework Equations ψ = Δxf(x) Δx = 0.007L...

One entangled particle held on a light sail nanoprobe sent to our nearest star, the other entangled particle in a lab on earth. Could this possibly provide instantaneous communication?

Hello! Is there any rule to do sums and products like the one in the attached picture (Lie.png) without going through all the math theory behind? I understand the first (product) and last (sum) terms, but I am not sure I understand how you go from one to another. Thank you!

Physical polarization vectors are transverse, ##p\cdot{\epsilon}=0##, where ##p## is the momentum of a photon and ##\epsilon## is a polarization vector. Physical polarization vectors are unchanged under a gauge transformation ##\epsilon + a\cdot{p}=\epsilon##, where ##a## is some arbitrary...

Homework Statement A 410 g particle in a semi-spherical bowl of radius 0.9 m is released from rest at point A at the level of the center of the bowl, and the surface of the bowl is rough. The speed of the particle at B is 2.6 m/s. The acceleration of gravity is 9.8 m/s 2 . What is its kinetic...

Hello all, I would like to know why an electron is accelerated in a linear accelerator because of the microwaves emitted by a magnetron?. Can someone tell me what are the relevant physics equations and what is the role of skin-effect here? Thanks a lot.

I was wondering if all particles of a given type are considered to be exactly alike.

This question was asked in an competitive exam in India. The relevant equations are momentum conservation in the classical sense and the 4 momentum conservation. My attempt: Classical momentum conservation would seem inaccurate since the kinetic energies are high. However, a straightforward...

Homework Statement (a) Cobalt has only one stable isotope, 59Co. What form of radioactive decay would you expect the isotope 60Co to undergo? Give a reason for your answer. (b) The radioactive nuclei 21084Po emit alpha particles of a single energy, the product nuclei being 20682Pb. (b) (i)...

We know that pions can be produced through decaying of kaons via weak interaction, but we also know in the acclerator the pions can be produced in pair via strong interaction. So my question is pions are produced via both strong and weak interactions?

Hi, I know and understand that heating a system causes the particles inside to increase in kinetic energy, due to the conservation of energy. What I don't understand is how does cooling a system causes the kinetic energy of the particles to slow down. Like how does cooling from sources such as...

Homework Statement The particle is thrown horizontally with speed 10 m/S (I believe from a height). Find the speed of it after 0.2 seconds. Homework Equations vx=v vy=gt v=sqrt(vx^2+vy^2)[/B] The Attempt at a Solution vx=10 vy=10*0.2=2 v=sqrt(100+4)=10.198m/S Am i right?

Homework Statement A particle of unit mass moves in one dimension with potential V(x) = ½μ2x2 + εx4 (ε>0). Discuss the motion of the particle. If the particle released from rest at x=a (a>0) express the time period T for the particle to return to a in the form of an integral and show that when...

It seems to me that we don't measure a particle because a particle doesn't have an objective existence independent of the wave function or does it? The wave function in this case would have to be real because you can't have probability without the underlying possibility of a specific outcome...

Hi, i am doing an introductory course in quantum mechanics (that would be equal to first two chapters in griffith's quantum mechanics). I have the doubt that what exactly do we consider in quantum mechanics. Let me say like the electron is a particle and when we will observe it will have a...

Homework Statement A ball is thrown horizontally wit speed 20m/s, from the top of the building which is 30m high. Find the time the ball takes to reach the ground? Homework Equations S= ut+0.5at^2 The Attempt at a Solution S=-30 u=0 A=9.8 T=? When I pluck the values I will get t^s=-30/4.9...

Homework Statement A sphere of radius R contains two spherical cavities. Each cavity has a radius of R/2 and touches both the outside surface of the sphere and its center as shown. The mass of a similar sphere without the cavities is M. Find the force of attraction on a small particle of mass m...

Homework Statement ISW walls at 0 and L, wavefunction ψ(x) = { A for x<L/2; -A for x>L/2. Find the lowest possible energy and the probability to measure it? Homework Equations Schrodinger equation ψ(x)=(√2/L)*(sin(nπx/L) cn=√(2/a)∫sin(nπx/L)dx {0<x<a} En=n2π2ħ2/2ma2 The Attempt at a...

using alpha decay as a concrete example is the energy of the alpha inside and outside the nucleus the same. it appears so from what I can see but alphas do have a range of energies usually up to between 4 - 9Mev. which is the same range as inside the nucleus. my question really is does...

Hello people, i was thinking about building a homemade particle accelerator but i do not know the materials and specifications to build one, can you guys help me know what thing do i need to buy and how to make one? Thanks

Hello everybody, I have two questions: 1) Is it possible to define a temperature for single particle (or atom or molecule)? If so, how? 2) How to model with quantum Hamiltonian an exchange of energy between a single atom (or molecule) and a reservoir at given temperature ##T## ? Thank you...

Homework Statement The eigenstates of the momentum operator with eigenvalue k are denoted by |k>, and the state of the system at t = 0 is given by the vector |{ψ}>=\int \frac {dk}{2π} g(k)|{k}> Find the state of the system at t, |ψ(t)>. Compute the expectation value of \hat{P}. Homework...

Homework Statement Working through problems in Mahan's 'Many Particle Physics' book, and at the end of the 1st chapter there's a question where we're asked to consider a fermion system with three energy states with eigenvalues E1, E2, E3, and matrix elements M12, M23, M13 which connect them and...

Hi physicists! When a particle and antiparticle collide, (annihilation) as i understand, it in some cases transform and radiate light, which I can buy. But what happen in the teleportation part, where the particle antiparticle pair accurs in an other part in the universe? Do someone have some...

Homework Statement Alrighty, so here's my problem in a nutshell: Some particle of mass m is confined to move along a ring of radius R. Since it's on a ring, it has periodic boundary conditions--i.e.: For the boundary defined as ##-\pi R \leq x \leq \pi R##, ## x = -\pi R ## and ## x = \pi R...