Particles Definition and 1000 Threads

I hear that deepest void of intergalactic space may contain say one particle per cubic cm. I don't want to quibble the amount but let's take that as close enough for my purposes. Now is this figure a statistical average so that if it were correct that each cubic kilometre of deep space would...

For example, do electrons, atoms etc. experience gravity? Is this proved by experiment?

I want to calculate that how many particles will be recorded by detector with MCNP. using the F8 tally which would provide energy spectrum, add all of data that related with full energy peak of spectrum, multiply by number of nps, then obtain the number of particles. is it correct ? i am not...

Subatomic particles can take the form of a wave or a particle. While in wave form, it is not like a physical wave, but rather a probability wave, (i.e. a wave of information about where the particle is probably located etc.) And while in particle form, a photon, for example, can knock electrons...

Comic is Superman/Batman #80 Superman explains that virtual particles are always spontaneous generated And that he's using his heat vision to (excite) the vacuum in order to accelerate the process. He's generating more virtual particles So my question is, how much energy or heat did...

Homework Statement A hypertriton (a bound system with a L hyperon together with a deuteron core (proton and neutron) is produced at the origin of the coordinate, (x,y)=(0,0) with a velocity of 0.94c (beta=0.94), flying along the x-axis. The mass of the hypertriton is 2.991 GeV/c2 . It decays...

Where can I find a detailed derivation for GHZ theorem for 3 particles?

Are there any relationships between the speed of light and the virtual particles in the vacuum? I mean that, Can I call it as a medium of propagation of a light beam?

It seems to be widely accepted on this forum that fields, not particles, are fundamental. In other words particles are made of fields. I have seen particles described in various ways such as being excitations of fields or eigenstates with known energy. This creates a problem for high school...

Homework Statement A point particle of mass m and charge q(>0) approaches to a point particle Q(>0) at a fixed position. When the distance between the two particles is L, the speed of the moving particle is v. The permittivity of the vacuum is denoted as Epsilon0. Find the minimum distance...

I was reading this paper https://arxiv.org/pdf/0805.4725.pdf It seems that the potential between the particles can be assumed of different forms, shouldn't the potential be a solution of the problem. Thanks

I am trying to code a simulator for fundamental particles. The problem is that on a subatomic level, force works differently than on a macroscopic level. Then there is also the problem of Heisenberg's Uncertainty Principle. How is a force applied to a subatomic particle? I did some research and...

Homework Statement Consider a system of two quantum particles. Each particle has two quantum states, one with zero energy and one with energy ε>0. For each of the three cases, draw a table of the possible microstates α of the system, and find the canonical partition function Z(β). a)The two...

If everything is made of atoms, and if atoms have so much empty space inside them - and if the building blocks of atoms are made up of wave-like particles that aren't solid (strictly speaking) - then why do cars crash and billiard balls bounce off each other, as opposed to passing through each...

For example should a neutron be considered as a point, or does it have volume?

Neutron and proton are themselves not composed of mesons, then how do they emit these particles inside the nucleus?

Homework Statement Show that it is impossible for an ultra-relativistic particle with ##pc>>Mc^2## to disintegrate into two identical massive particles of mass m. Homework Equations Conservation of four momentum The Attempt at a Solution The four momentum of the ultra-relativistic particle...

Homework Statement I don't understand how all the particles in a progressive wave can have the same amplitude. Surely they're all moving along the wave therefore cannot have the same amplitude. Homework EquationsThe Attempt at a Solution

I have read that when an electron is observed, it behaves differently to when it is not being observed. Could someone please expand on this, or indeed correct me. In what way does an observed particle behave differently to a particle that isn't being observed by somebody's consciousness?

Homework Statement Consider a gas sufficiently diluted containing N identical molecules of mass m in a box of dimensions Lx, Ly, Lz. Calculate the probability of finding the molecules in any of their quantum states. Calculate the energy of each quantum state εr, as a function of the quantum...

Mesons and baryons have both a ground state and excited states involving the same valence quarks but a higher mass (which can in principle be calculated from QCD). Fundamental fermions and bosons, however, do not appear to display this behavior. They have a ground state, and while there are...

So recently news broke about there being plastic particles/contaminants inside major brand water bottles (plastic), so since I don't drink bottles water but use some plastic bottles myself to fill in some fresh water from the local forest I then wonder how did the plastic particles got in the...

Hey! I was reading some script and when it comes to the cosmological redshift, it says, that only relativistic particles are affected by cosmological redshift. This does feel quite natural, however, I haven't been able to come up with an explanation that shows it with proper physics and...

<Moderator's note: Moved from a technical forum and thus no template.> I'm not sure how they got the extra (1/2)mv^2? My question is shown using pink font in the image below as well as my attempt.

Hello! I am a bit confused about the idea of spin. Let's say we have spin ##1/2## particles. This means that the spin along a random axis is ##\pm 1/2##, right while the values of the particle spin (i.e. the module) is actually ##\sqrt{1/2(1+1/2)}##? Also I am a bit confused about combining...

Homework Statement A particle A of mass m and initial velocity v collides with a particle B of mass m 2 which is at rest. The collision is head on, and elastic. The ratio of the de-Broglie wavelengths λA to λB after the collision is Homework Equations u initial velocity v final velocity The...

Knowing that virtual particles appear and disappear at the Planck length, what is the effect of the annihilation on space-time where the particles used to be?

So the Hawking radiation and the flinging of matter from the black hole, could this explain where all the matter goes? I am unsure of the theory for the second one, but if matter is broken to its quantum particles then why can't those quantum particles be in the Hawking radiation. Still very...

In simplified terms Hawking Radiation exists, because in the vacuum surrounding a black hole these subatomic-particle-pairs pop into existence and one of these particles manages to escape from the black hole. This stream of escaping particles is called Hawking Radiation, right?(Please correct...

I would likr to know what would happen if two beta particles were too collide with each other

In the first diagram above, if I understand it correctly, the photon turns into an electron positron pair and then back again to a photon. However, what exactly is happening in the second diagram at the bottom left hand corner? Is the electron being converted to an electron photon pair?

Hi, I was wondering that if there is some kind of interaction time between two charged particles. Imagine an electron shoot to ionize an atom. This electron interacts one of the electrons in the atom. Does the ionization depend on the velocity of the incoming electron? Is it possible that when...

do conductors have to be thought of in terms of protons and electrons? We can think of charged objects as continuous charge distributions for example without reference to any sort of real world particles. This is much simpler to grasp for me. Is the same sort of thing done for conductors, or...

From Weinberg's Quantum Theory of Fields Vol. 1, Chapter 4. Under interchange of two identical species of particles we have: \begin{equation} \Phi_...p,\sigma,n...p',\sigma',n...= \pm \Phi_...p',\sigma',n...p,\sigma,n... \end{equation} Plus sign for bosons and minus for fermions. As far as I...

Homework Statement Homework EquationsThe Attempt at a Solution [/B] Apologies for a bit hazy picture .Let the three particles be in a line after time 't' . If the inclined line (path of v) from the origin is perpendicular to the hypotenuse then we could write vt= v1cos45°t = v2cos45°t . But...

This is a topic that I have tried researching and I have not been able to find any meaningful information about it. The standard model of particle physics describes particles as point-like objects with no spatial extent. What I can't wrap my head around is how true point particles can...

Is it possible to find a particle large enough when entangled can create a wormhole for humans?

Heya, I was wondering what happens when you measure the spin of particles along several different angles on an entangled pair. As far as I understand Bell's theorem, it basically says that if you first measure particle A in some angle, and then measure a particle B at some some angle, you'll...

Homework Statement Problem Statement: A system consists of a long cylindrical anode of radius a and a coaxial cylindrical cathode of radius b (b < a). A filament located along the axis of the system carries a heating current I producing a magnetic field in the surrounding space. Find the least...

If we have a particle, say, an electron and we shoot it straight through an empty box. This box is surrounded by light sources on its two sides: So, if you consider the above cube, if we shoot a particle in a straight line such that it crosses the face ABEF and it crosses the face HGDC through...

I am confused about the mass-energy equivalence relation as it applies to nuclei and nucleons. For nuclei, I read of a "mass defect." Naively, I supposed that since it is a collection of nucleons bound together, it has a negative binding energy and this is the reason for the term "mass defect."...

I just finished Gordon Kane superb book "String Theory and the Real World" in one sitting. It answered most of my current questions about the field. I need some hard data. He mentioned: "More generally, where did the predictions for superpartner masses come from? Until recently there were no...

Arnold Neumaier, I have 2 elementary questions about your article “The Physics of Virtual Particles”. 1. In the paragraph headed “States.” on p. 4, of 13, you talk about states of a physical system, with a mixed state specified by a Hermitian operator ρ of trace 1 acting on the Hilbert...

As two particles become closer to each other, the gravitational force (or electric force) approaches infinity. If this is the case, then how does the Shell theorem work? If two particles are extremely close together, there should be an extremely large force. If we then build a sphere around...

Hi at all, I've the following question: How the fondamental particles (electrons, protons) are seen as matter waves, what shape and size should be these waves? They are wave-packets?

Dear members, The unit of stopping power is given as Mev/cm in many sources. It is easy to comprehend this unit.The mass stopping power, which is the total energy lost per path length by a charged particle, is defined as the division of MeV/cm to the density of investigated material, g/cm3, and...

Wikipedia quotes weak isospin values for some particles and not for others. Why? Is the concept of weak isospin as an observable quantity not meaningful for, for example, pions?

Why do fermions exchange bosons with each other?

<Moderator's note: Thread split off from https://www.physicsforums.com/threads/can-indistinguishable-particles-obey-boltzmann-statistics.939086/> This raises the question of how you know that there are two electrons in the first place. It seems to me that counting two things implies some way...

Many textbooks claim that particles that obey Boltzmann statistics have to be indistinguishable in order to ensure an extensive expression for entropy. However, a first principle derivation using combinatorics gives the Boltzmann only for distinguishable and the Bose Einstein distribution for...