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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Infrared-free QED and Higgsless standard model phenomenology

This is one of those "what if" fantasy world type questions. I like hard sci-fi so please no "well, you changed one thing about the world so now anything goes." :) What if the Higgs had no vev? That ...
10
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1answer
378 views

Why can the Euler beta function be interpreted as a scattering amplitude?

The Wikipedia article on the Veneziano Amplitude claims that the Euler beta function can be interpretted as a scattering amplitude. Why is this? In another word, when the Euler beta function is ...
8
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1answer
263 views

A moderate introduction to Hanbury Brown Twiss interferometry in particle physics

For astronomy, as originally invented, the Hanbury Brown Twiss interferometer is good for finding the angular diameter of stars and is not a rapidly fluctuating observable like the amplitude in ...
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1answer
73 views

Increased likelihood of photon emission due to “nearby” absorber?

Is an excited atom more likely to emit a photon if there is a similar atom in the ground state nearby ready to absorb it? When I say "nearby" I guess I mean that the absorber has an approximately ...
2
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1answer
69 views

Specific Heat of Nano Particles

Specific heat of nano particles is less than bulk specific heat of them. Why?
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1answer
53 views

$\mathrm{d} \Omega_{CM}$ for a $1\rightarrow 2$ particle decay?

The differential solid angle is described in e.g. Srednicki's QFT text but only for the case of scattering. Because in the case of scattering it's defined with respect to the incoming three-momentum ...
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1answer
20 views

Moseley's Law Conceptual Question

"Suppose one electron is knocked out of the K shell. This process leaves a vacancy, which we’ll call a hole. (One electron remains in the K shell.) The hole can then be filled by an electron falling ...
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1answer
66 views

Are subatomic partices n-dimensional hyperspheres or another n-dimensional shape?

This guy derives the formula for the volume of an n-dimensional hypersphere, which can also be found here on the Wikipedia page, and he shows that it is equal to this equation: $V_n = ...
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66 views

Any known relationships among quark masses?

Here is some numerology: Gen 1 Mass(d)/Mass(u) = 2 = 2 * 1 Gen 2 Mass(c)/Mass(s) = 12 = 4 * 3 Gen 3 Mass(t)/Mass(b) = 40 = 8 * 5 Does standard model make any predictions of relations? Do any GUT ...
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1answer
261 views

Pion production in proton-proton collision

Why is $\pi^0$ created in the high-energy collision $p+p\to p+p+\pi^0$?
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1answer
109 views

Photons and proper time

Why is there no proper time without inertial frame? In question n°95054 I learned that there is no proper time zero and no proper distance zero for photons because they are no inertial frames. That ...
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181 views

Why does mass in the universe have no limit in large size, but has a limit in small size?

We found VY Canis Majoris, a star so big it can't even be seen in scaled illustratations with the sun itself. However, we stop at particle physics, or quantum mechanics, i.e. particles, subatomic, ...
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361 views

What is the relationship between Luminosity, Intensity, and Flux?

I am always confused by the terminology: In high energy particle scattering, and in particular, in the context of collider physics, what is the relationship between luminosity, intensity and flux? ...
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127 views

What are the prerequisites to study CP violation?

If one would like to study CP violation, what would be the prerequisites for it? For example, until now I have not studied quantum field theory and have done very little classical field theory, but ...
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0answers
112 views

In what environments can a dipolariton form?

In what environments can a dipolariton form? The article in Science in which it is introduced discusses it in the context of an optical cavity in a semiconductor. Can this quasiparticle occur ...
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0answers
73 views

QCD corrections in W boson production

The book "Collider Physics", by barger and Phillips, deals with hadronic W and Z productions, and includes the $K$ factor which represents QCD corrections. However, when dealing with the hadronic ...
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104 views

Decay Amplitudes Notation

This question is mostly about how to interpret notation used in Particle Physics. I am given that at lowest order the rate of $b\rightarrow s\gamma$ is proportional to $\langle B_p|b^\dagger ...
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182 views

decay with initial velocity:

decay with initial velocity: All static particle decay to particles with momentum distribution in the same shape like that's implied by structure function and calculated by MG. but the decay of W ...
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24 views

How to calculate relative branching fractions of the $Z$ boson to specific pairs of “neutral lepton and anti-lepton”?

The PDG is listing values of "$Z$ couplings to neutral leptons" as $$ \begin{eqnarray} g^{\nu_{\ell}} & = & 0.5008 \, \pm \, 0.0008 \\ g^{\nu_{e}} & = & 0.53 \, \pm \, 0.09 \\ ...
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7 views

Can we say that nanomaterials have higher cohesive energies compared to coarse-grained counterparts?

Can we say that nanomaterials have higher cohesive energies compared to coarse-grained counterparts?
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22 views

Is there a finite frequency of physical interactions?

If particles use gauge bosons to convey information about various forces then is there something like a finite "refresh rate" at which they update information about themselves?
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32 views

Particle modeling in the context of numbers

We use either integers or rationals (or even complex numbers) for modeling the data. Hence, numbers impose constraints on the description of data. Namely, integers- that there exists the smallest ...
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16 views

How to find particle number fluctuation under given condition?

So we know the particle number fluctuation of a one room. Let it be equal to ФN, and we have to find the particle number fluctuation of a big room, which is just n times bigger, than a smaller one. ...
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25 views

Nilsson Hamiltonian - looking for problem and answers

I have been looking, unsuccessfully, online for academic problems involving the Nilsson nuclear hamiltonian. I understand the nature of the terms in the equation, but have never seen actual ...
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27 views

Quantum Hall Effect Dark Matter Detector?

Has anyone used a Quantum Hall effect detector to detect dark matter? I was looking at the following animation on wikipedia: ...
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59 views

What is the most fundamental peice of matter? What is it that thing which can no more be sub-divided?

I know that there is theory that strings are the most fundamental particles. But if it is a string, then it can be 'cut' into pieces, and if it can be 'cut', then it can be cut at infinitely many ...
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56 views

Oscillations and Majorana Neutrino

In neutrino oscillations, neutrinos can convert from one flavor to another. This implies individual lepton number is not conserved. Doesn't it also imply that, if the neutrinos have mass, the mass ...
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32 views

Quantum distance ladder

There is a lecture on how facts about the cosmos can be derived form rather simple observation. Is there an analogy for the small scale? Is there a technically simple observation that would imply, ...
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11 views

multiple frequency trapped power signal

is there any possibility to generate a waveform that consists of multiple power signals with different frequencies such that these signals travel together like they constitute [to form a ...
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0answers
37 views

Calculating the Neutron Stopping Power of complex materials

Is there a fast and convenient way of calculating the neutron stopping power of materials, consisting of multiple elements (e.g. doped crystals) without the need for Monte Carlo Simulation, that is ...
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57 views

Born rule and Feynman propagators

Let us assume that we want to describe the full process of photon emission by electron A and absorption by electron B. Therefore electron B must be on the forward lightcone of electron A. In the ...
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27 views

References on the LHC experiments

I'm looking for a references / short book which discusses what is going on LHC collider - specific experiments, collision processes, analysis of data, how exactly the facility is operating (not ...
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58 views

Lorentz force helix

I have a few questions about the Lorentz force. Is it possible to create a Lorentz force helix in a cloud chamber and if so how would this be achieved? How would the pressure inside the helix be ...
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46 views

What will happen to matter if there is a Higgs metastability decay?

Previously, on Save us from swallowing baby universes, please!, I pointed out the dangers associated with false vacuum decay. I wish to be more specific here. Suppose the Standard Model remains a ...
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34 views

Yan - Drell process

I'm looking for more information about Yan - Drell process but didn't manage to find a good place to learn from (still looking for one). I understood that this process can help us to understand the ...
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28 views

Lower bound bound on the mass of scalar bosons

Is there any lower bound bound on the mass of scalar bosons in nature. I know that a massless scalar boson would lead to a fifth force which would violate the equivalence principle. But is there any ...
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33 views

Fermi's weak interaction theory

In Fermi's theory, we have energy squared in the numerator of the cross-section which makes it diverge as energy increases. But isn't that the Fermi constant suppresses it with increasing order?
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15 views

Is it practical to slow down a plasma to with a spiral confinment to inrease direct plasma converter efficiency?

Instead of using tokomak/torus shaped tubing to confine plasma and slow it down to "useable" speeds. Is it practical to slow down plasma (with a magnetic field) over a long path using a spiral shaped ...
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53 views

Limit on the maximum mass

Is there a particular limit on the maximum amount of mass (matter and antimatter) that can be considered to be formed in free space simultaneously. I believe that for the phenomenon to occur the ...
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0answers
41 views

Reduced graphs and pinch-singular surfaces

I am reading a book on perturbative QCD by John Collins. In Chapter 5, the terms reduced graph and pinch-singular surface are used for the analysis of mass singularities. However, their meanings are ...
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86 views

Will the absorption of high energy gamma rays end up heating the absorping material?

By high energy I mean 100+ MeV gamma rays. I think that at this energy of photons, pair production is the dominating absorption process. So, as known, in pair production an electron and a positron ...
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70 views

Neutrons in nucleus

When I asked here why neutrons in nucleus (with protons) don't decay I was told that it would require energy for the neutron to decay, it wouldn't give energy. And since that wasn't really what I ...
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145 views

Pair annihilation - how to generaly solve these types of problems?

Simple question regarding pair production: Can a collision of an electron with a positron result in two photons? I have this problem to solve and I doubt this is even possible. Please provide some ...
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58 views

Preons and 't Hooft condition

If some fundamental particles, like leptons or quarks are composite (e.g.in preonic models), or the same with gauge bosons or the higgs particles. How could it be possible that preons were more ...
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94 views

History of the elementary particles

The current model for the elementary particles is the standard model. I understand its basics It is for me however, difficult to wrap my mind around it without having some kind of knowledge of the ...
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119 views

Intensity counts

I am a postgraduate student currently working on the area of pulse oximetry. My question is: Is the light intensity emitted by the LEDs (Red & Infrared) measured in counts has the same value as ...
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0answers
50 views

the effects of an ln-prime transformation to physical models

I have rather a "toy" type of modelling-problem that appeared to me along a book I am writing on number theory. I would be outmost thankful for any concrete or inspirational answers, including ...
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62 views

What's the real value of screening length?

I know that the screening length (R) is an effective distance over which the nucleus of an atom is active, since it is screened by the orbiting electrons.Various derivations for R have been proposed, ...
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77 views

Pareto efficiency and Standard Model parameters

Pareto Efficiency is a well understood concept in economics, which basically is a condition where no one actor could be made better off without some one being made worse off. This condition allows ...
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41 views

why is the modelisation of elementary particle as a two dimensional object in contradiction with General Relativity?

This is asserted by Trinh Xuan Thuan in his book "Chaos & Harmony" chapter String theory.