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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Newton's gravitational constant $G$, the reduced Planck constant $\hbar$, the speed of light $c$: the Dream Team of moderators?

The three great constants of Nature are well known: the speed of light $c$ (special relativity), the reduced Planck constant $\hbar$ (quantum mechanics), Newton's ...
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184 views

Describing the Higgs mechanism to non-particle physicists

I'm sure I'm not the only person with this problem at the moment. I have been asked to give a public (not quite public, scientists, just not physicists) about 'this Higgs boson thing'. I am trying to ...
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64 views

What is Higgs transition?

In recent publications there is a frequent mentioning of the so-called "Higgs transition" in connection with magnetic monoples. Can anybody please describe the phenomenon in simple terms? For ...
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583 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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162 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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115 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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80 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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118 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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197 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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29 views

Uses of the accidental isomorphism $SO(5)\sim Sp(2)$?

Some of the accidental isomorphisms of low dimensional Lie algebras have very important applications in physics. The theory of angular momentum makes use of the fact that $SO(3)\sim SU(2)$. ...
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29 views

Running of the Higgs mu term (or: running of individual mass terms in a complicated mass matrix)

I am wondering how to calculate the (one-loop) beta function for an individual mass term that appears in combination with a number of other mass terms in the coefficients of a number of fields. What ...
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15 views

Centrality analogue in proton-proton collision

If we look at ion-ion collisions one can represent most observables as a function of centrality (0-5% centrality class event etc.). Is there any possibility to introduce centrality analogue in ...
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18 views

Isothermal Expansion in Real Gases

I understand that for a ideal gas in the case of reversible isothermal expansion, $\Delta U=0$ and $-Q=W$ but in case of a real or van der Waal gases, how can I find $Q$, $\Delta U$ and $\Delta S$?
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30 views

Reference for the non-perturbative origin of the baryon masses

I'm looking for nice introductions to the non-perturbative generation of the baryon masses.
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17 views

Difference betwen combinatorial and correlated background in particle physics?

What is the difference, in particle physics experiments, between combinatorial and correlated backgrounds?
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25 views

What is the limit of directly detecting a resonance?

Some resonances are extremely short-lived. With a lifetime of $10^{-23}$ seconds, they would travel just about the size of the proton ($10^{-15}$ m) even if they traveled at the speed of ...
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22 views

Motion of charge particle under electric and gravitational fields

I am working on one experiment in which the charged particle falls under the effect of gravity and passes through the electric field in between. I want to know what is the charge of the particle? ...
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21 views

How much cheaper and smaller on average is SiPM technology over conventional PMTs?

I've heard it said that some of the major advantages of silicon photomultipliers are its low cost and compactness when compared to widely used photomultiplier tubes, but haven't found much information ...
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16 views

Calculation of removing a nucleon from a nucleus

I would like to calculate the energy needed to remove one nucleon - proton or neutron - from a nucleus. What is the equation to be used?
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17 views

intuition about Gauge in Hall bar geometry with 4 leads

Please tell me about the kind of gauge I should use for calculating the resistance in a 4 lead hall bar geometry.As when I use Landau gauge it will make my leads transitionally invariant only along ...
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50 views

How to theoretically determine electric charges of $W^{\pm}$ bosons?

I just realised that I don't remember how to conclude theoretically that $W^{\pm}$ bosons have electric charges of $\pm 1$. After some searching I'm quite surprise that I couldn't find a satisfying ...
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41 views

Summing up independent mass measurements to recover $Z$ boson mass

I am trying to calculate the $Z$ boson mass from a list of $\mu^+\mu^-$ data (momentum). We have been asked to make five blocks of data from the total amount of 10k. Then calculate the mass via ...
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19 views

What does a completely negative Greens function in frequency mean?

What can a Greens function of frequency mean when it is always negative? The Greens function is for the photons as the following: (It's derived by Matsubara method to enter the thermal effects and the ...
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8 views

how to completely remove the charge from the glass bubble particles?

Do you have any idea on how to completely remove the charge from the glass bubble particles (25-32 micrometer diameter)? Thanks
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9 views

What is 'transparency rate' for ionization chambers?

I was reading a paper a little while ago and I saw that the author noted the 'transparency rate' of an ionization chamber. The ionization chamber had field shaping wires at the entrance and exit that ...
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36 views

When optically pumping a lasing gain medium with another laser, does Stimulated, or Spontaneous emission dominate?

Much of my reading seems to indicate that laser pumping results in a fluorescent stokes shift but somehow photon vector is maintained. I've seen the phrase "Spontaneous Fluorescence by Stimulated ...
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27 views

Is the continuity (discontinuity) one of the intrinsic properties of all physical objects?

Is the continuity (discontinuity) one of the intrinsic properties of all physical objects? How do we define continuity? Which of the definitions of continuity are used (and why) in physics? This ...
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18 views

Penning Trap Simulation

I'm currently working on a particle tracker and I would like to implement a Penning trap. I think I might have a problem with the field of the electrical quadrupole. My idea was to place 2 dipoles and ...
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40 views

Constant Rayleigh Scattering Cross Section

in the Review of Particle Physics - Interactions of Particles with Matter, there is a plot that gives the cross sections for different interactions of photons with matter. One of them is Rayleigh ...
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49 views

Is there a machine readable format of the data tables in Particle Data Group PDFs?

Is there a machine-readable format of the tables of data in PDG documents such as this one? http://pdg.lbl.gov/2011/download/rpp-2010-booklet.pdf Something such as JSON, XML, CSV, HTML, or anything ...
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49 views

Nuclear Interaction Stopping Power

Hello again question board. I'm in need of some help with my b) question for homework I have. Following question is verbatim: "How thick should a wall of shielding iron be to absorb a 10 GeV/c pion ...
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114 views

General definition of vector spinor and spin

I am looking for basic and exact definitions of fundamental physical consepts in graduate level. I reach this following definitions. Could you please help to improve these definitions. Spin: ...
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59 views

Mathematical formalism to include wave and particle perspectives of light

Does the exist any mathematical formalism (model) describing the behavior of light and incorporating its particle character (divisibility, quantization) and wave character? (i.e. quantized wave model) ...
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19 views

in an organic semiconductor, what is the average distance travelled by an exciton?

In an organic semiconductor, what is the average distance travelled by an exciton up to recombination? How is this value related to the morfology / structure of the organic semiconductor?
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15 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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23 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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40 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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29 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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36 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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71 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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34 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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82 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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35 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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69 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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40 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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59 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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85 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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217 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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83 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 ...