Particles Definition and 1000 Threads

I would like to be able to qualitatively describe what particles are according to quantum field theory without saying anything wrong. Is it correct to say the following things about, say, an electron? (1) Electrons are excitations of an underlying quantum field, the electron field. There is a...

1) are all particles/photons theoretically entangled at birth but we just never or will know? Or is it under specific conditions? 2) how much of the photons that the sun emits entangled particles/photons?

It seems that the entanglement of two particles does not change with time and can cross long distanced as long an neither particle decoheres with the environment. This makes me wonder if the wave function for that entanglement can have any time or space dependence? I only did a brief search for...

Homework Statement I would like to understand why alpha particles experience large angle deflections and if this is the same thing as recoil of alpha particles? Do large angle deflections occur near the end of the alpha particle track or can they occur at any point along the trajectory...

What evidence is there that gluons are even particles? They were originally proposed to supply an extra quantum number to comply with the Pauli exclusion principle. So gluons are supposed to carry a color-anticolor charge in order that the quarks in baryons would add up to the color white. But...

Calculate the range of sizes of the particles. 
 ν= velocity of decent d = diameter ps = density η = viscosity P1 = density v= (d^2 (p_s-p_1 )g)/〖18〗_η Rearrange for the diameter. v= (d^2 (p_s-p_1 )g)/〖18〗_η 〖18〗_η v= d^2 (p_s-p_1 )g (〖18〗_η v)/(p_s-p_1 )g= d^2 √((〖18〗_η...

I've heard in a general way that string theory can describe the properties of the fundamental particles through standing waves or resonances of strings. Is this in fact the case, and if so, can someone provide a link to the relevant research papers?

Homework Statement A particle of mass m1 and momentum p1 collides with a particle of mass m2 at rest. A reaction occurs from which two particles of masses m3 and m4 leave the collision along the angles θ3 and θ4 respectively, measured from the original direction of particle 1. Find the energy Q...

I was watching videos on YouTube and this question suddenly popped into my head: If I was able to push a sub-atomic particle (proton, electron, etc...) a distance of 1 Planck length. Excluding all the quantum interactions and uncertainties, is it possible to measure/calculate how fast the...

I am a masters student in the UK. For my project I have to monitor the efficiency of zinc sulphide detectors for monitoring alpha particles in liquid solutions. I need to model things like the proximity of the detector to the liquid, the size of the detector and the thickness of the light-tight...

Interference (trying to measure) single "particles" in a double slit experiments causes them to discontinue wave like behaviour and perform as "particles". Has the consequence of a series of interference with single "particles" been mapped when they arrive at the detector, and does any such...

I understand photons and elections fit into the probalistic rules of QM. Are there any other elementary particles (more massive) that don’t obey the point/wave duality?

According to what I have read and watched (I am new to the subject) the empty space is actually full of temporary virtual particulars that spontaneously and continuously emerge from nowhere and then disappear from the nothingness again but from where comes so much energy for so much creation of...

For a null particle, ds^2 = 0, Timelike, ds^2 >0, spacelike, ds^2 < 0, how would you characterize the motion of each particle?

Is it possible to take two identifiably different particles of the exact same type (I previously called them indistinguishable in error?) which have different quantum states (say a different distribution in position or momentum Hilbert space) and physically cause them to have identical states...

Homework Statement [/B] I have solve the rest of this problem pretty easily and see no problems with working with Indistinguishable particles, Distinguishable particles, fermions and Bosons. Part c has me very confused though about what it is even asking. Suppose a system with equally spaced...

There are infinite number of charges each with charge q along a straight line at a distance of 1,2,4,8,16,… … … unit from a point. What is the electric field at this point? No idea about it.Please help me out.

hi there, i have always loved Science, and from astronomy transitioned into particle physics because of the Higg Boson, learning about the implications of Dark Matter, and Dark Energy. i am also studying things like Zero Point Energy, have always been fascinated with the flight dynamics of...

Hello, I encountered the following statement in my lecture notes and there is a couple of things I don't understand:"Let's consider two particles with spins ##s_1 = \frac{1}{2}## and ## s_2 = 1## with a spherically symmetric interaction potential. Assume these two particles are in a two...

Homework Statement Many heavy nuclei undergo spontaneous "alpha decay," in which the original nucleus emits an alpha particle (a helium nucleus containing two protons and two neutrons), leaving behind a "daughter" nucleus that has two fewer protons and two fewer neutrons than the original...

Homework Statement A proton strikes a stationary alpha particle (4He nucleus) head-on. Assuming the collision is completely elastic, what fraction of the proton’s kinetic energy is transferred to the alpha particle? Homework Equations Pi = Pf Ki = Kf The Attempt at a Solution Tried finding...

If talking about a particle rotating around an axis away from it by r. if the particle is moving with constant angular velocity ω. is the linear velocity constant or no? Now what I know is that since we have Vt= ωr, so r doesn't change, as well as ω, so Vt is said to be constant. but I think...

It is said (hopefully no need to give references for such a common statement) that the electromagnetic field of a given charged particle is infinite in range (albeit converging to zero as the distance goes to infinity). However, given that charged particles apparently did not exist at the...

This may be a pretty basic question ,but i'll through it out any way. As a project i built a muon detector from 2 matched PMTs and 2 4x6x1 plastic PVT scintillators. And pulse processing NIM modules. I was getting pretty good coincidence reading,some what less than predicted.ie ( 1...

The drawing shows three particles far away from any other objects and located on a straight line. The masses of these particles are mA = 340 kg, mB = 567 kg, and mC = 139 kg. Take the positive direction to be to the right. Find the net gravitational force, including sign, acting on (a) particle...

Hi I'm wondering how when a charged particle is accelerating it both emits energy in the form of em radiation while also gaining kinetic energy. All of that energy comes from the thing accelerating the charged particle, yeah? Is that necessary, like it is not possible to give a charged particle...

https://home.cern/about/updates/2018/09/lhcb-experiment-discovers-two-perhaps-three-new-particles http://lhcb-public.web.cern.ch/lhcb-public/Welcome.html#LHCCCKM This is very exciting news! What exactly does it say about the strong interaction?

I'm currently reading Schwartz's QFT text "Quantum Field Theory and the Standard Model" (although this question does not specifically pertain to this text) and I've got two questions: 1. At the beginning of chapter 6 he talks about how we may consider the system to be non-interacting in...

Homework Statement Please see the attached images. The position of a particle moving along a coordinate axis is given by ##s(t) = t^3-9t^2+24t+4## where t is greater than 0. a) Find v(t) b) At what time(s) is the particle at rest? c) On what time intervals is the particle moving from left to...

Homework Statement A particle B is standing still while another one, A, is moving towards it with initial 4-momentum ##(E,p,0,0)##. Calculate the change in particle A's 4-momentum as viewed from the particle B's rest frame, in terms of the initial energy E and the scattering angle ##\theta##...

What do ‘events’ refer to when collisions occur at the LHC. The Higgs Boson was found from a blip in the graph of Events vs Energy at about 125Gev. It shows an excess of events at this energy. But what events are in excess and why does this indicate the existence of a particle?

Hi everyone! Here the question(s). In the vacuum, the sub particles pop up and down (annihilation). If this is right, we can tell that the all matter is the attempt of sub particles to remain alive? so, is my glass of wine a desperate attempt of electrons, quarks, and all the other particles...

I've never been able to get my head around the idea that forces are particles. In the case of fermions, a particle seems to be a natural concept. Even though it's really a wave, or an excitation in a quantum field, I can envision it as being something in a particular place. For bosons that...

Homework Statement A particle A moves along the line y = d (30 m) with a constant velocity (v= 3.0 m/s) directed parallel to the positive x-axis (Fig. 4-40). A second particle B starts at the origin with zero speed and constant acceleration (a = 0.40 m/s2) at the same instant that particle A...

Why all particles of same type identical? All electrons are identical to each other, all protons are identical..etc. It is as if they are copy pasted from each other! For me this is one of the biggest mysteries ever, why we don't detect more massive or less massive electrons? Is it related...

Homework Statement [/B] I'm stuck on part (b) and (c) of the following question Homework Equations The Attempt at a Solution The partition function was ##Z_N = 2 cosh(μBβ)## where ##β = \frac {1}{kT}##. From there I used ##U = - \frac {∂}{∂β} ln (Z_n)## to get ##U = -NμB tanh( \frac...

Weinberg considers (p.68 QFT Vol. 1) particles with mass M > 0. The Little Group is SO(3). He wants to calculate the rotation W(Λ,p) ≡ L-1(Λp) Λ L(p). He says that for this we need to choose a standard boost L(p) which carries the four momentum from kμ = (0,0,0,M) to pμ. He then shows the...

Homework Statement Two identical particles, each having charge +q, are fixed in space and separated by a distance d. A third particle with charge -Q is free to move and lies initially at rest on the perpendicular bisector of the two fixed charges a distance x from the midpoint between the two...

After some reading, I'm quite confused about the vacuum state in interacting QFT. I've read the @A. Neumaier post on "The Vacuum Fluctuation Myth," where he notes that "bare quantum field theory with a cutoff, the vacuum is a complicated multiparticle state depending on the cutoff – though in a...

... and how were these then able to go on to form atoms?

I have not formally studied physics but am interested in quantum physics. I have studied calculus so I know a little bit about mathematics in case the answer requires it. My question is, when a physicist conducts experiments at the quantum level, how do they know that what they are "seeing" is...

Hi, For a particle in a box (so that the momentum spectrum is discrete), we can write the identity operator as a sum over all momentum eigenstates of a projection to that eigenstate: $$I=\displaystyle\sum\limits_{p} |p\rangle\langle p|.$$ I was wondering what the corresponding form of the...

How could electrically charged particles be massless before the symmetry breaking? Wouldn't the energy stored in the electric field contribute to particles mass?

Homework Statement If, N = n × NA Where N = Number of particles in the substance and n = Amount of substance in moles (mol) and NA = Avogadro Number = 6.022 × 1023 particles mol-1 To find the number of particles, N, in a substance: N = n × NA To find the moles, n, of substance, n = N ÷ NA...

In this Nima Arkani-Hamed paper on page 5 I found the sentence: These constraints are an artifact of using fields as auxiliary objects to describe the interactions of the more fundamental particles. In Schwartz's QFT book I also get away with the impression that the Poincaré irreps (i.e...

Hello, I am studying the entanglement in quantum physics, especially the Aspect's experience where 2 photons initially correlated keep this correlation through the measure of their polarity. The Wikipedia article is only available in French, but there is an article in English written by Alain...

The concept of Identical Particles in non-relativistic QM seems a little shakey to me. All elementary particles of a certain type, say electrons, are supposed to be identical except for a handful of degrees of freedom like spin direction, position, etc. (For some reason, energy and momentum...

Since electrons pop in and out of existence, are they virtual particles?

I did a little more research, please clarify. So the electric field is directed to the proton and that emits light? Can you get into more detail? I am not educated in math so this is hard to understand at this point. I understand how electrons emit light but not protons. So is the magnetic...

The interaction p + π- → n + π- + π + may proceed by the creation of an intermediate 'particle' or resonance called a rho. This can be detected as a peak in the plot of invariant rest mass energy of the emergent pions versus frequency of pions observed. My question is quite simply, invariant...