Particle physics is the study of the fundamental forces of nature as they are embodied in the interactions of elementary and composite particles at high energies and short time and distance scales.

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2answers
56 views

What is voltage?

I am a little unclear on what voltage actually is and I am trying to find out what the physical cause for voltage is. Is it the speed of the electrons through the conductor or is it an excess of ...
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0answers
22 views

can light bounce off another light? [duplicate]

If light is a wave and a particle (wave particle duality), is it possible for light to bounce off another light since light bounces of another matter(particle)?
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1answer
58 views

How to model matter in code [on hold]

I've always had a passion for science, understanding and programming. Given my interests, I thought a cool thing to do would be to model real world theories in code (with visuals) so that others may ...
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1answer
16 views

Is the decay of the positive Kaon into 3 pions a weak processs or strong one?

The strangeness is not conserved in the decay of the positive Kaon into 3 pions. so this decay should be a weak process but on the other hand parity is conserved in this decay. Kaon has odd parity and ...
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0answers
26 views

Covariant projection method - Meson bound states

I have seen many papers that discuss the production or decay of mesons ( quark bound states ) to make use of the covariant projection method where the product $\upsilon\bar{u}$ of the quark spinors ...
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0answers
12 views

Collision symmetry and measuring the asymmetry in the Drell-Yan process

I saw a talk the other day about an asymmetry in the Drell-Yan process caused by CP-violation: Apparently one way this can be measured (ATLAS is doing this) is to collide protons and observe the ...
6
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0answers
34 views

What happens to Hydrogen-Boron plasma at 3 billion Kelvin?

A recent popular report states (beware, I believe it is not peer reviewed and this slightly smells like a PR stunt) that a private company TriAlpha has made some notable progress towards ...
2
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0answers
19 views

How to let Pythia to output the complete event record in LHEF or StDHep format?

I am currently using Pythia 6.4 to simulate some processes (I do not have the intention to upgrade to 8). Now, I need Pythia to output its event record in the format of LHEF or StDHeP. I accidently ...
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0answers
33 views

Infinitesimal transformation by Noether's charge [on hold]

Can anybody explain me the physics of the commutation relation : $ [Q,\phi_{i}] = it_{ij}\phi_{j}$ ; where, Q is Noether's charge and $\phi_{i} (i=1,2)$ are components of an isodoublet?
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0answers
20 views

Properties of vector potential

Given the definition of vector potential as, $ A_{\mu}= \sum_{k} \partial_{\mu}\theta F^{k}$ , where F are the generators and $\theta$ are the parameters of the symmetry group. I have two questions ...
2
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0answers
32 views

Gauge transformation and Special relativity

While explaining gauge theories, a book makes a comment that the U(1) transformation definition, $ U= e^{i q \lambda(x)}$ is analogous to a special relativity transformation in freely falling ...
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1answer
14 views

Vector potential in gauge transformation

While applying Gauge transformation, $\psi\prime = U \psi$ , where $ U= e^{i q \lambda(x)}$ , transformation law for "Vector Potential" comes out to be : $ A_{\mu}\prime= ...
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1answer
62 views

Fractional number of particles in the universe?

Is it possible, that the metagalaxy contains a fractional (non whole) number of particles or fractional number of a particular kind of particles (such as electrons)? Sorry, if my question is stupid, ...
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0answers
23 views

Units in Plasma Physics

What are the units people use in plasma physics? I am having hard time converting an equation from an old paper to SI units. I saw temperature being defined in eV. I assume this is eV/kB with kB ...
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1answer
50 views

Probablity Wave and Wavefunction [closed]

Are wave function and probability wave same? Well I am a bit confused about wavefunctions and probability waves. I read in Fabric of the Cosmos by Brian Greene that they are same. Please help me and ...
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0answers
35 views

Is there a local canonical ensemble partition function for a Bose-Einstein gas?

The grand canonical partition function for a Bose-Einstein gas is $$ Z_{\text{grand bos}} = \exp \left( \sum_{j=0}^{\infty} -\ln \left( 1-e^{\beta(\mu-\epsilon_j)} \right)g_j \right) $$ where $\beta$ ...
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3answers
195 views

Why do electrons and positrons exhibit opposite helical motion in a magnetic field?

When you throw an electron through a solenoid, it moves helically around the field lines, as per this schoolphysics illustration: © Keith Gibbs 2013 Then if we were to throw a positron through the ...
3
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2answers
106 views

Can quarks be considered elementary?

In our current theories all hadrons are made up of quarks and gluons. This view reduces considerably the big family of hadrons by providing a very logical structure in which all quantum properties ...
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1answer
18 views

How is transverse momentum of an object related to its energy in experimental high energy physics? [closed]

We use TLorentzVector function SetPtEtaPhiE() to set Pt, Eta, Phi and E of an object in ROOT. If I multiply the Pt of that object with a constant, how would E of the object evolve? Is the relationship ...
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1answer
57 views

Why should an electron orbit decay?

I have heard physicists say that 'if' an electron was a particle then it's orbit would decay so it would crash into the nucleus. How do they propose that it would lose it's energy in order to decay?
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1answer
41 views

Is possible to use optical fiber to transmit light to streetlights? [closed]

I was thinking about this idea: Only one lamp, inside a optical fiber structure, transmitting all the light through a lot of optical fiber cables direct to streetlights. (I guess that the cables ...
0
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1answer
118 views

If a black hole is just warped spacetime, then where is the electric charge?

I've heard Kip Thorne repeatedly state that matter is destroyed when a black hole is created, that all you are left with is distorted spacetime. "The idea that black holes are made from very ...
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1answer
18 views

Why do I not observe single/double escape peaks for K-40

A question on gamma spectrometry here. If I'm looking at a background gamma spectrum with a big peak at 1460KeV (approximately 180 counts) and I attribute this peak to the presence of K-40, should I ...
1
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1answer
26 views

Nuclear decay of V-48

I have a question on the "decay" of Vanadium-48. The reason it's in inverted commas is because I'm not sure whether decay is the right word. Basically what I'm trying to work out is whether it's ...
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1answer
109 views

If there is a boson that carries mass, why not space, or time? [closed]

If the Higgs Boson carries mass, why doesn't there exist more bosons that carry other fundamental properties such as volume/distance (space), time, or even spacetime? Also if bosons carry force, but ...
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1answer
76 views

What's the difference between vacuum particle-antiparticle annhiliation and regular annihilation?

Why does vacuum particle-antiparticle creation and annihilation result in nothing rather than photons? What is the difference between that and regular annihilation that does result in photons.
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0answers
34 views

Is there any difference in mixing and oscillation of neutral mesons?

I have often read about neutral Kaon oscillation or neutral B meson mixing. Both are described by the similar box diagrams. So I want to know if we can say neutral kaon mixing and D meson oscillation. ...
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1answer
17 views

What is the total velocity/force on a particle in fluid?

I am now facing a fluid-particle interaction problem. I would like to simulate particle motion in a fluid. I do know the external force acting on a particle (dielectrophoretic force in this case) ...
3
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1answer
36 views

One-point function and VEV in $\phi^4$-theory

Why is it that the one-point function in the $\phi^4-$theory, for example calculated from the generating functional, always gives zero value in absence of external source i.e., $J=0$? If there is ...
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1answer
63 views

How do gluons form virtual top quark or bottom quark loop?

Main mechanism for the production of a higgs boson in Large Hadron Collider is the gluon fusion that is two of the gluons binding these protons collide and those energetic gluons form virtual top or ...
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1answer
35 views

How long is a higgs boson stable for before it fully decays?

How long after the creation of a higgs boson is it stable for on average?
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2answers
46 views

When a charged particle absorbs a photon, does the particle get 'pulled' or 'pushed'?

When a charged particle absorbs a photon, does the particle accelerate towards where the photon was coming from or where the photon was going
1
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1answer
59 views

Why standard model particles cannot be dark matter particles

I'm interested if any of the particles in the standard model could be potential candidates for dark matter? I know that we do not see dark matter, therefore dark matter does not interact ...
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3answers
62 views

Are there an even number of particles in the universe

I generally understand that every particle has an anti-particle that is created along with that type of particle with opposite effects (unless there is no charge), and that if that anti-particle comes ...
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1answer
81 views

Why cannot massless particles carry charges? [duplicate]

How to show that massless particles do not carry charges from QFT's point of view?
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0answers
16 views

Evidence electrons are fundamental particles [duplicate]

Is there any evidence that entities like electrons and quarks are indivisible, i.e. not composed of other, smaller entities? And have I just made a category error by even asking this question?
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1answer
32 views

How many pairs of nuclei collide in heavy ion collisions?

As each bunch of heavy ions consist of a large number of nuclei it does not seem unlikely that multiple binary ion collisions will occur as it does in p-p collisions. However, should this be the case, ...
0
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1answer
57 views

Spin angular momentum

Spin angular momentum is defined as $\Sigma^{i}= 1/2 e^{ijk} \sigma_{jk}$ . Thus, I can write $\Sigma^{1}$ as $[\gamma_{2},\gamma_{3}]$ . I want some insights on this definition. Also, Can anybody ...
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1answer
35 views

Why classical open system and Bose-Einstein condensate are not fundamentally the same?

The classical partition function for an open system is given as $$ Z_{\text{max}} = \sum_{N=0}^{\infty} \dfrac{h^{-N}}{N! } \prod_{j=1}^{N} \left( \sum_{i=0}^{\infty} e^{-\beta (E_{ij}-\mu)} g_{i} ...
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1answer
30 views

In geometric optics we treat light as a collection of particles?

I've been reading the book "Geometric Mechancis" by Darryl Holm and the in the first chapter he treats geometric optics. There the author talks about light rays and those light rays looks like ...
0
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1answer
64 views

Is neutrino-based communication possible?

Referring to this article, where we see there are three flavors of neutrinos, got me thinking of simple binary-based communication, but more like the UDP protocol where we can live with dropped ...
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2answers
127 views

Is there any evidence to suggest that subatomic particles have 3D physiscal size? [duplicate]

What I'm asking is do subatomic particles like a proton have a volume or any 3 dimensional size? Or are they just points?
2
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1answer
49 views

Particle masses

if there is no theory to predict/calcukate the masses of the fundamental particles, where do they get the values for the quarks, as quoted in the standard model? And since the composite particles get ...
1
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2answers
137 views

Electron-positron annihilation with photon production. Virtual particle

I'm wondering if someone could explain me what happens to charge during electron-positron annihilation. For example if weak interaction (like electron + positron forming neutrino and antineutrino) ...
1
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1answer
58 views

Form factor for Proton

To find the charge distribution of proton , we study electron proton scattering and compute the form factor to find the cross section. The form factor comes out to be Fourier transform of charge ...
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0answers
22 views

No bottom quark in parton distribution function

CTEQ6M Parton Distribution: http://www.scholarpedia.org/article/Introduction_to_Parton_Distribution_Functions My understanding is that bottom/top quarks can exist (at least temporarily) as ...
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0answers
42 views

Is there a difference between two of the same fundamental particle?

Is there a difference between two of the same fundamental particle? For example, is there a difference between two electrons or two protons, or quarks or gluons? If there is a difference then how ...
1
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1answer
46 views

How would one get the particle beam in Stern Gerlach experiment

How would I get a beam of silver atoms? I imagine this to be problematic, since the silver atoms are neutral. How would I accelerate them?
6
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1answer
475 views

Can two colliding photons create a Higgs Boson?

The LHC discovered the Higgs using the following decay mode: $$ H^0 \rightarrow \gamma \gamma $$ This got me thinking: if we reverse this mode, will it be valid? In some annihilation/decay pairs, ...
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0answers
53 views

Is the Higgs field responsible of only 1% of the proton mass?

This post is a sequel of: Where does the majority of the mass of the usual matter come from? The following answer of @hft: Your question asks why the "current quark masses" [see ...