Hey everyone, I'm trying to get started with Genie software for neutrino simulations. I'm looking for any good resources, tutorials, or documentation that could help me learn and use the software effectively. Here are some specific questions I have:

Tutorials: Are there any good tutorials or online courses available to learn Genie?

Documentation: Is there comprehensive documentation available for Genie?

Community: Are there any active online communities or forums where I can ask questions and get help?

Any advice or recommendations would be greatly appreciated. Thanks in advance!

Is tachyon a real thing a particle that can travel faster than the speed of light?

Hi everyone,

I’m a PhD student working on Higgs boson reconstruction through the ( H \to ZZ \to 4\ell ) channel using Pythia8. I’m trying to simulate events where the Higgs decays into two Z bosons, each subsequently decaying into two leptons (e.g. 2e2mu , 4e , etc.). My goal is to reproduce the invariant mass distributions of the Higgs from the final-state leptons.
Key Questions:

1. What specific Pythia settings should I use to handle Higgs production and decay properly?
2. How can I efficiently implement selection cuts like ( p_T ) thresholds and invariant mass windows for Z candidates?
3. Has anyone successfully reconstructed this decay and can share tips or code snippets?

I’m currently using:

• Gluon fusion for Higgs production.
• H to ZZ to 4e decay, filtering events based on Z1 and Z2 invariant mass cuts.
• ROOT for histogramming invariant masses.

If you’ve worked on something similar or can guide me on best practices, I’d greatly appreciate your input. Thanks in advance!

Hi everyone,

I recently came across this statement in Introduction to Elementary Particles by David Griffiths about early relativistic quantum mechanics "given the natural tendency of every system to evolve in the direction of lower energy, the electron should runaway to increasingly negative states radiating off an infinite amount of energy in the process".

I understand why the electron would evolve toward lower energy states—this aligns with the principle of systems moving toward stability. However, what I am struggling to derive mathematically is how the electron radiates an infinite amount of energy in the process.

Can someone explain this mathematically with the reasoning behind the phenomena?

Hi, I have a question about high energy particles that don't interact often with matter. I read the Mars rover had to be restarted after a weakly interacting particle passed through a memory register in the onboard computer and effectively changed a 0 to a 1, causing the computer to fail and have to be restarted on a backup.

I understand these particles are constantly there ,around us and moving through us constantly and it got me thinking about the effects on electronics on a vehicle moving at a increasing speeds under the speed of light.

My Question. What would be the effect in terms of the number of particles that pass through the electronics as velocity increases, would the 'hit' rate increase leading to an increasing potential for equipment failure? Or would the hit rate remain the same as time dilation begins to have a greater and greater effect?

Any insight would be appreciated, and please excuse the way my question is put together. I'm not sure I have the nomenclature to ask in the right scientific language.

I was reading some posts on this page and noticed a post about emergence, which then I searched up. It looked oddly similar to quantum tunneling, borrowing energy from the universe. But the more I researched, the more I misunderstood it. Can someone please tell me if emergence and quantum tunneling are the same, and how quantum tunneling actually works?

Thanks

Im thirteen and have been doing particle physics for a year and a half now, but without any knowledge of vector fields or calculus I am not able to grasp such mathematical concepts such as the Schrödinger equations, Maxwells Equations, or Professor Zwiebach's Quantum Physics lectures at MIT. Does anyone have any material on the internet or a course that I can follow to understand quantum physics?

I realized too late I really have a passion for physics primarily particle and astrophysics / astronomy. However I'm terrible at math and never went beyond basic algebra. Is it impossible for me to have any sort of career path or job with physics or astronomy? Are there any resources or possible adjacent careers that I could get into?

So as you may know, the Electron-Ion Collider has began early stages of construction and is due to start operation sometime in the early 2030s. It's supposed to be huge for helping us u derstand the strong force (my favorite force).

Curious what other colliders are due to start operation around the same time (early 2030s) that can help us understand any of the following: the weak force, strong force, gravity, dark matter, dark energy.

Just a thought incase humanity screws up a particle accelerators cooling systems

Hello, I am in the first year of a master's degree in optics and photonics, and it was not the field I wanted to do in my master's degree (I don't hate it but it is not the field I like the most), I want to do theoretical physics abroad, and I think I will graduate in this master's degree before leaving my country and doing another master's degree in theoretical physics (probably in Germany), now my question is whether I am wasting my time or whether this first master's degree can be very useful in my career even if it is not very related to the second one I want to specialize in, and whether as a student it can help to find a job while doing my second master's degree (laboratory assistant, teaching etc...). it should be noted that this master's degree in optics and photonics has a multidisciplinary aspect and is also oriented towards materials physics since many of the teachers who provide this training come from this field.

edit: I know that doing two masters is pointless if you end up doing a PhD in one of the two, but can't the first be useful if it allows you to acquire more skills (especially interdisciplinary skills) and if it opens doors to more research subjects? and i didn't really have a choice in doing this master's degree since it's the only one available at my university and I can't go elsewhere for the moment for personal reasons.

At the LHC, they always describe things in terms of nucleon-nucleon centre of mass, i.e. in their 2018 PbPb run, nucleon-nucleon root s was 5.02 TeV. Why do they not use the ion-ion centre of mass energy? How do you calculate the ion-ion centre of mass energy? I'd assume that due to nuclear effects, it's not as simple as scaling up? Does the way you calculate it change for an asymmetric collision? Say Pb-proton or proton-Pb.

Bjorken and Drell focus their book on relativistic QM on hole theory, and I've had quite a difficult time making a connection between the statement of the theory and how we see it in the Dirac equation. I'll also say that I know the hole theory isn't really used elsewhere but this is more of a logic thing that I need to make click

So they state that hole theory is based on the assumption that there are actual negative energy states that are occupied, which is stable due to Pauli exclusion. When sufficiently excited, they can transition to a positive energy (+E) state and leaves a hole in the negative energy continuum. The absence of this electron acts as if it has charge +q_e and some positive energy. The text states it should be equal to +E as well but this doesn't really make sense unless the incoming radiation had energy exactly 2E. But I don't think this point matters too much.

Now my issue is actually making a correspondence between an unoccupied negative energy state and the solutions to the Dirac equation. From classical QM we associate the amplitude of a wave function with the presence of a particle, and I am tempted to apply the same intuition to the negative energy states here. So its not really clear how we show that parts of solutions to the Dirac equation correspond to the absence of negative energy eigenstates.

I keep trying to find a solution to this but I am always left telling myself that in order to actually use this theory, we would need a wave function that includes every electron in the universe, or else there is no way to know which negative energy states are missing. The explanation in the book sort of just says "the presence of a positron can be seen as the presence of an electron running backward through space-time with charge conjugation" but doesn't really explain the jump from how we associate the absence of negative energy solutions with what we see in a solution to the Dirac equation.

I hope this question makes sense, it's been tripping me up for months and I would really like to resolve it. Any help is appreciated.

sorry if this is a stupid question but i watched a documentary that explained a concept and id like to explore it more but cannot find the name for the life of me. it was about how there are tons of particles moving around and on some level we are able to experience the particles come together as bigger objects. what is this called? tia!

Random shower thought I had this morning (Yeah, I'm a nerd), but basically like the title says.

I've seen the photo of the fire extinguisher type container that holds the hydrogen gas which serves as the proton source for the LHC. Passing the H2 through magnets strips off the electrons, and then the protons are then sent their merry way into the LHC system. However, do they have to deal with isotopes of hydrogen such as deuterium or tritium, or do they even care?

Out of my field, but part of an ongoing discussion with a friend. Has there actually been a measurement of the Higgs isospin?

I'm currently studying DY process, and my work required me to know about the drell yan like process. Can anyone help me with it? Some resources would make my life more easy.

EDIT: I'm studying Drell yan process where q, q bar goes to Z and then to electron positron pair. Now, My professor told me there are some processes who can mimic the final stage of the DY process( where they give ee- in the final stage). I want to know about those process which can mimic this,( he told something about WW and t t bar)

I hope I'm able to make my question clear now.

Hi everyone, the thing about particles in jets still confuse me. I would assume only hadronic particles would be there inside a jet ideally but not sure why electrons and muons are there in it. Any explanation would be appreciated.

I have a question that I have asked a lot of people and nobody seems to know the answer to.

You shoot a bullet at an empty soda can. It makes two clean holes. Entrance exit. They are roughly the size of the bullet. The can is otherwise undamaged.

What happens as we drastically increase the velocity of the bullet. From its normal velocity 900m/s to 900km/s to 10% c to 99% c.

If we assume this happens in space so there are no atmospheric effects, does the can rip apart or vaporize or does the hole become even smaller and more perfectly circular?

I know at a certain fraction of c nuclear fusion will occur at the point of contact between the bullet and soda can. Will this release rays that harm people standing near the can?

If the can does rip apart, is it because of the velocity being imparted into the walls of the can pulling them in the direction of the bullet? Or is it because of the heating at the point of contact causing vaporization of the metal which causes overpressure inside the can like an explosion? Or is it because the radiation released heats the can and vaporizes it?

If there is rapid heating and vaporization at the point of contact, wouldn't the bullet have already carried that explosion far away from the can before it has time to expand? So maybe the can will be otherwise undamaged aside from the hole?

This is an empty soda can with an open top. I know if liquid were in there it would obviously explode.

I am doing an undergraduate degree and I want to create some plots from LHCb data.

I have two branches a MM (Measured mass) and a MMERR (Measured mass error). I am creating a histogram using matplotlib and I want to add error bars for each histogram bin.

How is this typically done? There is an yerr=True option using the mplhep library although this doesn't take into account the MMERR. Is it fine to ignore the MMERR values? I also found this stats post https://stats.stackexchange.com/questions/214287/calculating-uncertainties-for-histogram-bins-of-experimental-data-with-known-mea and I am wandering if this is the correct way to add errors?

https://preview.redd.it/jdlg7khziqyd1.png?width=1874&format=png&auto=webp&s=e8c832159088b621ba2f8debf8adeaf71d58ded4

I'm nearing the end of my undergraduate degree and have space for an extra class. I am hoping to apply to graduate school and study particle physics. I am more interested in theory and like computational projects. I found this course which obviously stands out since the Lagrangian is defined via optimization. I am wondering, for anyone with more knowledge than me, if this course would be worth taking, or if it would be a complete waste of time. Thanks a lot for any advice!

Why does quark not hold quantization of charge (u=2/3,d=-1/2) instead of integral of charge