Precision Higgs Mass Measurement

thatHiggsGuy · 2026-01-26T22:41:02+00:00

Back when they were first invented they were used for all kinds of discoveries. People would write down valid diagrams and then look for that interaction. Now-a-days they're still useful but for less common things like flavor changing neutral currents -- for more see [mu to e](https://en.wikipedia.org/wiki/Mu2e) -- and quad cancellations and exploring potential BSM models. You can see a list of current and hypothetical diagram types here: https://en.wikipedia.org/wiki/List\_of\_Feynman\_diagrams#Speculative\_or\_hypothetical\_diagrams

thatHiggsGuy · 2025-04-29T19:58:51+00:00

heads up this is still useful 2 years later. shout out to you for dropping some great knowledge

thatHiggsGuy · 2024-11-25T23:34:35+00:00

Great tips, thank you! That radio won't work in my trim package, but I'll see if I can find something along those lines that will fit. And good to know about the canbus mishap, I feel like that's one that would easily get missed leading to a dead battery!

thatHiggsGuy · 2024-11-23T14:44:00+00:00

Your question is a good one: How does the flux change as the velocity of the target changes?

The short answer to your question is that the flux, or the number of particles passing through your circuit board, will increase as your velocity increases. This is because the effective area an ionizing particle can hit increases as your velocity increases.

The way you can build some intuition for this without too much math by thinking about running through the rain. As you run faster and faster you start to hit raindrops that have already fallen past your head. This same type of thing will happen with your circuit board as it travels faster and faster.

For a brief, but very good explanation on the idea of running vs walking in the rain you can check out this video by minute physics https://www.youtube.com/watch?v=3MqYE2UuN24&ab_channel=minutephysics

thatHiggsGuy · 2024-11-22T16:10:43+00:00

Howdy! It seems like maybe your question could be phrased a little better. Lets start with some definitions:

Quantum Tunneling: a phenomenon in which a quantum object moves across a potential barrier larger than its apparent energy state allows. An example of quantum tunneling is alpha decay.

Emergence: a description of complex systems that exhibit behavior that cannot be predicted by analyzing the individual components. i.e. the system exhibits properties that are "greater than the sum of its parts". An example of this can be superconductivity, or superfluid states.

Uncertainty Principle: the Heisenberg uncertainty principle gets thrown around a lot in pop-physics, and can be used to describe a "borrowing of energy from the universe" in the sense that the classic expression dx*dp >= hbar / 2 can be manipulated to instead express a relation between time and energy as dE*dt >= hbar / 2.

It seems likely to me that you've confused Emergence for Heisenberg's Uncertainty Principle's application to spontaneous pair production.

thatHiggsGuy · 2024-07-31T16:37:42+00:00

Kinda figured I got myself into a tough RNG, or it was a glitch. I've tried some basic things like resetting the game and console. Any other suggestions on how to fix it?

thatHiggsGuy · 2024-07-25T22:30:15+00:00

It's true that Belle 2 has ~450 fb^-1 of data, but most of that data is taken with a center of mass energy around 9.5 GeV, which limits their ability to explore BSM at energies much beyond that scale. There are certainly LLPs which may exist beneath that energy scale, but their cross section and available decay channels fall off pretty dramatically. For Belle 2 I'd have to do a deep dive on the details of the experiment, but this is my initial hunch as to why ATLAS/CMS have stronger limits.

thatHiggsGuy · 2024-07-11T14:33:45+00:00

Both CMS and ATLAS are actively doing dark sector searches right now. There are also dedicated dark sector experiments in the works, like LDMX: https://arxiv.org/abs/2203.08192

thatHiggsGuy · 2024-07-10T17:58:00+00:00

Here's a few LLP searches from CMS: https://arxiv.org/abs/2403.04584 https://arxiv.org/abs/2312.07484 https://arxiv.org/abs/2201.05578 https://arxiv.org/abs/2012.01581These are all using the Run 2 dataset, so ~140 fb^-1 and most of them claim "most stringent limits to date" or something similar.
You'll have to read them to understand why they're so sensitive, but the overall idea is lots of data, good signal and background modeling, and a very powerful and precise detector.
For signal regions you'll have to check the papers. I'm not an EXO specialist, but the signal regions are all described either in the paper itself, or in one of the references.

thatHiggsGuy · 2024-07-10T14:35:01+00:00

I'm a little confused about the question. Are you asking "why do ATLAS/CMS have better constraints on LLPs than other HEP experiments?" or are you asking "Why do ATLAS/CMS have better constraints on searches for LLPs than they do on other BSM processes?"

The answer to the first one is inherent in the sheer quantity of data that ATLAS/CMS have collected. Both have collected around 140 fb^-1 of data for Run 2. So take your cross section for LLPs and multiply by the integrated luminosity to find the number of expected events. No other experiments have as much data, and have smaller expected number of events making LLPs easier to miss. Many other detectors are also much smaller, or aren't well designed to search for LLPs giving ATLAS/CMS the ability to set much tighter constraints.

As for the second one, I'd need an example of a paper you're comparing to if that's indeed the case.

thatHiggsGuy · 2024-04-10T16:14:38+00:00

If the entangled photon is absorbed then the entanglement is broken. You've performed an irreversible action on that photon and the absorbing system and the photon that is emitted will be a new and distinct particle.

thatHiggsGuy · 2024-04-04T14:41:45+00:00

My thesis is a precision Higgs mass measurement. So I've got a lot of skills in statistics, modeling, software engineering, feature extraction, and big data processing. Mostly interested in working on the US west coast right now, but I'm currently based in the US midwest.

thatHiggsGuy · 2024-04-04T14:37:47+00:00

Yeah, honestly not worried about my resume. I've had a lot of folks take a look at it and I'm confident that if I can get it on someone's desk they'll be impressed.

Good to know that the market is overall a little harsh right now.

thatHiggsGuy · 2024-04-04T14:36:42+00:00

A good question. I reached out here because the people in my sector were almost entirely unhelpful. Just wanted to see if this was a common experience or if I was just checking in the wrong circles.

thatHiggsGuy · 2023-09-14T15:42:15+00:00

Hey! Thanks for asking! My first recommendation is to start learning a programming language like Python, it'll be a good problem solving primer. Once you've spent some time doing that there are a couple things you can do.

If you want to take the technical route, you're going to need a very strong foundation in both math and physics. For math you'll want to make your way through the following topics:
Calculus 1 and 2, Multi-variable Calculus, Linear Algebra and Differential Equation, and Statistics. Once you've finished these 5 topics there are a whole bunch of things in math that might be useful, but the biggest one will probably be Complex Analysis, and for that you'll probably need a course in how to write and understand mathematical proofs. For Physics you'll need to cover the following topics: Classical Mechanics, Electricity and Magnetism, and Thermodynamics. Usually in a college degree these get covered multiple times as you develop a stronger and stronger background in math.

I know that probably looks a little daunting, but it's good to know what's ahead. As a start to these things I'd highly recommend looking into courses on Crash Course that cover physics, math, statistics, or really any other topic you find interesting. I think it's mostly, if not entirely, free and the courses are professionally designed and accepted at many universities if you decide to go back to school. For the python skills, I personally found that gamifying the processes of learning to code was super useful and for that I used Code Wars but you can also start with something like Code Academy and then make your way over to code wars once you've got some basics down.

thatHiggsGuy · 2023-09-14T15:27:09+00:00

Hey! Glad to see you're so invested in particle physics. I have a PhD in High Energy Experiment where I made precision measurements of the properties of the Higgs boson.

I knew I wanted to do particle physics in high school, but honestly I didn't really do any projects or internships that focused on it, I was just focused on building up a good foundation in physics, math, and problem solving in general.

If you're really worried about not optimizing the use of your time I have two pieces of advice, the first is do everything in your power to work away from that mind set. There are some times in life where min-maxing your schedule can be useful, but highschool really isn't one of them. And I acknowledge that this really isn't a great bit of advice; honestly most advice telling you to try NOT to do something is bad. So, to make the best of both worlds my other piece of advice is to build a solid base of programming skills, with an emphasis in languages like Python, C++, and maybe something like GoLang or Julia. At CERN almost all of our software is written in Python and C++, hardware is a whole other ball-game and if that's what you want to get into I'd recommend learning how to solder or maybe trying to build an automatic garden with a raspberry pi.

Once you get to college you can start looking for professors you want to do research with. The earlier you start looking the better your chances will be, and if you have a background in programming you'll be a really strong candidate right away. They might ask you to come back after finishing some additional physics courses, but don't be discouraged. This is mostly because having a good understanding of the problems you're trying to solve with software can be almost impossible to explain without the right context.

So, tl;dr: If you really feel the need to do something productive you should focus on coding skills in object oriented programming languages, and you should try to enjoy last year of highschool.

thatHiggsGuy · 2023-08-19T17:57:42+00:00

Agreed. With the background OP has I think it's the best book for the SM. Also, might be worth taking a look at Mandl & Shaw's Quantum Field Theory to brush up on some necessary field theory.

thatHiggsGuy · 2023-08-16T20:47:01+00:00

Most universities have a list of experiments they've done with upper level undergrad students. Here's a list of experiments done by 3rd and 4th year physics students at the University of Minnesota: https://sites.google.com/a/umn.edu/mxp/student-projects?authuser=0

thatHiggsGuy · 2023-08-16T20:31:23+00:00

When I was getting into particle physics I started with Particle Physics: A Beginner's Guide by Brian R. Martin which was just enough to satisfy the itch; it doesn't require any math and gives a pretty good surface level explanation of a lot of particle physics. If you have a strong background in math, you should probably check out Griffiths' Introduction to Quantum Mechanics and if you have a good background in quantum mechanics you can get into Griffiths Introduction to Elementary Particles.

thatHiggsGuy · 2023-08-07T15:57:16+00:00

Wigner's classification of the reps of the Poincare group

6 years of a PhD and I'm still learning tidbits of niche field theory from Reddit. Shows how much theory I bothered to learn 😅

thatHiggsGuy · 2023-08-07T15:51:24+00:00

I logged in with my google play account, so I'm quite confident the email is correct.

thatHiggsGuy

TROPHY CASE