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How are quantum states of particles represented in particle processes?

For example, lets say we have an electron positron annihilation scenario. What will be the density matrix of the electron and the positron? What will be the density matrix of the photons?

21:05 UTC


Building a betatron

Hey, I’m planing on building a 2.3mev betatron. I pretty sure most of you know that Michio Kaku did something similar when he was in high school. Well, I’m in high school and I don’t really have anything better to do. I have a university professor at UofT helping me with the math and theory. I’ll keep you guys updated on my progress.

02:20 UTC


How were muons and tauons named?

I know they are named after the respective Greek letters, but how do they correspond them with letters in the first place?

16:23 UTC


Why was there a perfect ratio of quarks immediately after the big bang?

So I'm watching a series on the big bang on Prime Video, and the professor spoke about the epoch of quarks in the fractions of a second after bb. During that epoch the quarks combined to form the protons and neutrons making up almost all matter today.

Being that a proton has 2 up quarks and 1 down quark, and a neutron has 1 up quark and 2 down quarks, how is it that there are not any unpaired quarks wandering the universe today that couldn't find partners to form hadrons? Do unpaired quarks suffer from some sort of decay if they are 'orphaned' for a certain period of time?

21:48 UTC


Can someone help me better understand the science behind this image? More details in the comments.

07:55 UTC



Total layman here. Is their evidence of anything after the collapse of the wave function that isn't deterministic?

Wrong sub? Shoot me a quick reply.

18:24 UTC


Seeking to improve my QFT/HEP foundations as a PhD in another subfield

I have a PhD in physics; I studied theoretical AMO/quantum information. I'm starting a new role soon where I will be working at the intersection of quantum information and high-energy physics (think quantum simulators for HEP/QFT applications). There are some good white papers and review articles from both HEP and QIS communities on these crossovers which I am currently working my way through. These will position me well in the short term, but for long-term success, I can tell I'll need to improve my foundational understanding on the HEP/QFT side so I don't have to treat that half of problems as a black box. I've had some coursework, but graduate school classes were a while ago and this subfield was never my main focus.

I'm looking for advice for recommended books, lecture notes, etc for self-study in this space, both in physics (field theory, phenomenology, HEP experiment...) and mathematics. I was hoping people might have some suggestions specific to my needs and prior experience -- I need something more technical than you would give a layperson, but I'm less focused on details of calculations and more interested in hitting key concepts.

21:42 UTC


Probably stupid question about particle colliders

Hi guys, I have a question about particle colliders.

I understand that they use electromagnetism (I get that it's more complicated) to accellerate particles to high speeds and collide them, but how do you "get" a subatomic particle, and how do you put it into a collider? Just something I've never understood.

I've tried searching for the answer but I can only find results about how particle colliders work themselves, without the process of getting the particles.

Thanks in advance!

12:07 UTC


Can we know the exact coordinates of an electron?

07:18 UTC


Tour a particle accelerator, ask real scientists questions and more at Jefferson Lab.

The Thomas Jefferson National Accelerator Facility in Newport News, VA is having its biennial open house tomorrow Saturday June 8 from 9am-3pm, admission and parking is free. Learn about superconducting materials, supercomputers, particle accelerators, particle detectors, nuclear physics research and much more. See our web page for more information.

13:04 UTC


Bremssthalung Radiation and Black Body Radiation

Hi folks. I have 0 formal education in physics but with a strong interest and the incredible resources on the internet and some well written books, I have managed to acquire a small bit of knowledge. My question concerns thermal radiation and bremsstahung radiation. Please correct any errors in my understanding. To The best of my knowledge, bremsstahung radiation is the electromagnetic energy that is emitted when a charged particle give up kinetic energy. Thermal energy is kinetic energy at the molecular level and thermal radiation occurs when the molecular kinetic energy is given up as electromagnetic energy. My question is: is there a relationship between bremsstahung radiation and black body or thermal radiation? Any thoughts are much appreciated.

22:58 UTC


CORSIKA 7 OR 8 animate visualization

Hello, I would like to know if anyone is familiar with corsika 7 o 8 and to know if you could please explain to me how you created an animation of an EAS, either resulting in a GIF or a video, I saw that it could be used using them such as map3plot or coast but I can't find a specific manual for that or any paper that explains it in detail. Or if you have any other suggestions on how to do it, I would appreciate it.

^(As a note, in Corsika 8 I have an error that I don't know how to solve when running the ctest, an error appears in point 6, I suppose it is due to fluka.)

20:47 UTC


Elemental properties and the number of protons

I asked a question earlier, and I don’t think I properly asked it, thank you if you answered my last post.

Protons isolated have no elemental properties, but when clumped together they take the shape of a unique character. Why would 8 protons make oxygen? In another universe could 8 protons be gold?

If you have a video game that would create universes, what game settings could you tweak to where the recipe for copper is 31 protons.

What game settings could you change for material to look the same, but swap properties? So for example, tin and copper everything is the same except tin is more conductive in your new universe?

17:42 UTC


Is it possible that there could be a field, but no real particles for that field exist?

As I understand it, finding the Higgs boson was really important because it proved that the Higgs field (and therefore, the Higgs mechanism) is real. But is it possible that the Higgs field might exist, but for whatever reason not be able to form real particles? Is it possible that only virtual particles are possible in a field?

19:59 UTC


Are there theories how one proton in a atom in another universe could be uranium or another order?

Basically what information sets the laws of physical properties based on a clumping of protons. Thanks I’m going crazy.

18:09 UTC


I need help - please check this poster for errors

Tell me anything wrong with it or if I'm missing any crucial information (thanks)

10:39 UTC


How do virtual photons mediate the attractive/repulsive force of opposite/like charges?

I recently watched a video by "float head physics" explaining how photons can push charges by the oscillation of electric field and the magnetic field, which made me question how does this interaction cause the attractive force of opposite charges? From what i understand virtual photons are exchanged between charged particles and the force the virtual photons can produce increases inversely to distance (due to energy-time uncertainty principle), but if a photon can only push, then how does it cause the attractive force? Can photons pull? Does the pulling force also increases inversely to distance?

04:57 UTC


Niels Bohrs representation of a Xenon atom (1923)

17:02 UTC


Is it possible to make a particle accelerator out of household items?

I was just wondering if there is a way to make an accelerator because the cyclotron that I made with aluminum didn’t work as I didn’t have enough voltage, is there a way to make a low voltage accelerator, although this completely is the opposite of reality?

17:40 UTC


Where Would I Even Work

So me and my friend both want to pursue physics, specifically nuclear or particle. The problem is I’ve been searching all over and I don’t even understand what job positions are available, what would I even do with a degree in particle/nuclear physics, and where would I find these jobs.

03:14 UTC


Graviton Questions

I am super young and have started getting into this field of particle physics...

Just so that I know that I properly understand:

Graviton – AntiGraviton

  • Obliterate each other
  • Supposedly “antimatter” is “less than” “matter” 
    • Gravitons remaining are the matter that creates gravity today
  • Gravitons are essentially needed to exist because gravity is one of our four fundamental forces that make us up (strong nuclear, weak nuclear, electromagnetic, and gravity)
    • So if all other forces have these particles (such as W and Z Bosons, etc.), gravity must have something (correlating to photons in the electromagnetic field)
  • It may be hard to understand gravitons as it is the weakest of the four fundamental forces
  • Is there concrete evidence of its existence?
  • I don’t fully understand particle accelerators, I may be stupid (probably, just spilling my thoughts), if we make a vertical particle accelerators would it be possible to use the nature of gravity in order to discover more concrete evidence of gravitons? Excuse me on this point, I may be slow…
  • Is there evidence that gravitons don’t fully exist?

I am young and new so please excuse any of my irrational comments... I am well open to learning and to understand my curiosity.

01:32 UTC


Which one is correct 1 or 2?

1 is correct because of the spins of mesons and baryons, Is that the only reason why are Hadrons (mesons and baryons) classified as fermions and bosons.

Plus would it be right to say that elementary particles are fermions, bosons and hadrons. while fundamental particles are leptons and quarks?

05:10 UTC


Has reciprocity been proven in theory of relativity?

Are there any actual tests made that prove that the time dilation is symmetrical between two moving observers? All the papers I've found on this are theoretical.

06:45 UTC


Animator interested in particle physics - What type of software is used?

Hey there! I'm coming from a fine arts based animation program, newly electronic hobbyist, with interest in particle physics.

I have an acquaintance who is finishing his thesis at McGill who told me there are jobs in this field for animators. I was curious to know which type of software is used, any examples of what is useful to those studying or doing research in the field?

I already know to expect it to be about code and formula manipulation to generate graphics, but would like to know where to start.

I am appreciative of any respectful answer/direction provided. Thank you.

17:31 UTC


Xray spectrum of Cu

hi, does anyone here know to plot spectrum of xray target Cu like this? what formula should i use? help me pls

15:47 UTC


What are some best institutes for PhD in Neutrino physics?

14:50 UTC


Derivation of microscopic nuclear cross section, \sigma that involves the de Broglie wavelength?

Anybody know where I can find this?

and/or does someone know of the breit-wigner single resonance formula with h-bar instead of \sigma?

21:53 UTC


Learning Particle Physics

I was just going to start learning Particle Physics from David Tong's papers (University of Cambridge). I already know the base of modern physics (starting from Bohr's Model, Photo electric effect up until nuclear physics) should I know something else before starting? Any suggestions are appreciated. Thanks.

17:13 UTC


Help needed with a research question

I'm in a group with 4 people and we decided to make a particle accelerator for a research paper that is a pass or fail. This research paper decides whether we pass high school or not, so it's extremely important we can do our project We've built a homemade linear particle accelerator that shoots helium at 2000 eV, but we can go higher. The setup consists of a rough vacuum pump and diffusion pump, an electron gun and a phosphor screen at the end of the accelerator. The method of acceleration is through radio frequency acceleration in drift tubes. Lastly, there are two deflecting plates before the phosphor screen which slightly change the trajectory of the particle before hitting the phosphor screen.

We can measure the energy of the beam and pressure. Is there any research question that we can use that doesn't end with binary results?

07:28 UTC


Dumb question about electron cloud model.

Is there a meaningful difference in how we consider the location of nuclei vs electrons? My layman’s understanding is that electron cloud model describes the location of electrons as a cloud of possible locations with the nucleus at its center. Less mass + higher velocity = really hard to observe so maybe the nucleus is just significantly more concrete in its position?

Is the nucleus more locked in place because of mass or does it have its own kind of cloud of possible location when we try to observe it?

What kind of incorrect assumptions might I be making?

02:21 UTC

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