What is High energy physics: Definition and 84 Discussions

Particle physics (also known as high energy physics) is a branch of physics that studies the nature of the particles that constitute matter and radiation. Although the word particle can refer to various types of very small objects (e.g. protons, gas particles, or even household dust), particle physics usually investigates the irreducibly smallest detectable particles and the fundamental interactions necessary to explain their behaviour.
In current understanding, these elementary particles are excitations of the quantum fields that also govern their interactions. The currently dominant theory explaining these fundamental particles and fields, along with their dynamics, is called the Standard Model. Thus, modern particle physics generally investigates the Standard Model and its various possible extensions, e.g. to the newest "known" particle, the Higgs boson, or even to the oldest known force field, gravity.

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  1. AditiShahani

    Admissions Exploring the Universe: Pursuing a PhD in High Energy Physics

    Can somebody help review my SOP. I’ve already applied to one school but have many other schools to apply to, I know it needs lots of improvement so harsh critical comments are welcomed. Thankyou. I first encountered the concept of virtual particles during my studies of the Casimir effect; I...
  2. T

    I Intersection of Condensed Matter Theory + High Energy Physics

    Hey all, I was just wondering where I could find a current review of the major problems that are being discussed at the intersection of condensed matter theory and high energy theory (+maybe quantum information)? Just looking for some inspiration on what the most "popular" problems being...
  3. cemtu

    I K-Shell, Low-Energetic Photons & Photoelectric effect

    At low photon energies, the probability of the photoelectric effect to occur increases, but the probability of the photoelectric effect to happen also increases when going towards most inner shells like K shell but inner shells require much more photon energies to be broken, so isn't there a...
  4. cemtu

    I Thomson Scattering when low-intensity light meets an orbital electron

    Can you explain to me the reason why Thomson Scattering can not explain what happens when light meets an electron at low intensity, and what does that have to do with light being a wave or particle or relativistic/QM effects? https://en.wikipedia.org/wiki/Compton_scattering
  5. cemtu

    I How does a photon interact with the EM field of a nucleus?

    How does a photon interact with EM field of a nucleus thus exchange momentum and recoil the nucleus when pair production happens?
  6. cemtu

    A Why KE of Annihilation Electrons Differs?

    We know that when a high energy gamma ray(E >= 1022 keV because the total energy of 1 electron at rest and 1 positron at rest is 511 keV) passes near a high Z(atomic weight) atomic nucleus interacts with the electrical field of the nucleus and there is a probability that this high energetic...
  7. codebpr

    A Finding a suitable form factor for a given set of conditions

    This is basically a physics problem but I will try my best to highlight the mathematics behind it. Suppose I have two functions: $$T(z,B)=\frac{\text{z}^3 e^{-3 A(\text{z})-B^2 \text{z}^2}}{4 \pi \int_0^{\text{z}} \xi ^3 e^{-3 A(\xi )-B^2 \xi ^2} \, d\xi },$$ $$\phi(z,B)=\int_0^z...
  8. N

    Feynman diagram for ##\mu^+\mu^-## production in ##p\bar{p}## reaction

    I was able to solve b) but I am confused for a). I understand that in the proton-antiproton collision, only two quarks (one from proton and other from anti-proton) can be combined to get a virtual photon that in turn creates muon and anti-muon. I don't understand what would happen to the other...
  9. waglebivu

    A To set up parameters for the sherpa tool

    How to set the parameters - photon index and metal abundance in the CIAO-sherpa tool for an x-ray source?
  10. Azerack

    Admissions Safety School Programs for a Physics PhD

    Hi, this is my first time using the Physics Forums so please let me know if this question belongs somewhere else. I'm a senior undergraduate at a mid-size institution in the United States seeking to purse a PhD in High Energy Theoretical physics or Quantum Information/Computing. I'm aware these...
  11. M

    I Are there currently working colliders with unequal beam sizes?

    I know that for any coliders beams are not exactly the same size but they can be approximated to the same value as the deviation is relatively small, such as LHC. My questions: 1- are there currently working or planned colliders with unequal beam sizes? 2- for coliders of different particles...
  12. S

    I Varying laws of high energy physics in inflation?

    I am have some questions that have arisen while reading an old but interesting article by Andreas Albrecht [1] that cites an article by Andrei Linde in the 90s on cosmic inflation [2]...Albrecht's paper is related to his ideas on "clock ambiguity" in which he proposes that the laws of physics...
  13. G

    Studying Methods to improve my skills in studying papers

    I'm a PhD student in high-energy theory and this is one point I have been struggling with for a while. When I study a paper what is the most efficient way to do so? For example, should I try to rederive everything following the author's reasoning? Should I try to take notes, and if so how to...
  14. P

    Job Skills Any industry jobs for physics grads requiring no programming?

    Hi all, my question is as title. I am a fourth year PhD student in US and planning to graduate early to get in industry or community college. I major in high energy theory, and I have no coding/simulation skills at all (not interested at all). Thus, my situation is that professionally I have...
  15. dara1998

    I What is the main challenge of high energy physics?

    Hi, my question is that what is the main challenge of high energy physics? what is the best theory that maybe explain it and why it would not be accepted?
  16. R

    B Which one is more efficient in generating high energy Gamma rays?

    According to https://apps.dtic.mil/dtic/tr/fulltext/u2/a351472.pdf the big pulsed power accelerator, HERMES III, generate electron beam with peak energy at 22 MeV and average electron energy at 16 MeV and the resulting photon energy which is bremsstrahlung radiation is approximately 2 MeV...
  17. S

    What is the best search engine for graduate students in the HEP field?

    I found PF when I google one question.
  18. A

    Other Best journals in High Energy Physics (formal theory)

    Hello, I request inputs about selecting a journal to submit an article in High Energy Physics. This is in formal theory as opposed to Particle Phenomenology. The article is more than ten pages so PRL is not an option. How would you choose between JHEP and Physical Review D? Which is rated higher...
  19. W

    I Detection of Neutral Currents

    In decay processes where no mixing between quark families is present, the mediator of the weak force is the neutral ##Z^0## boson. If that is the case, how is it experimentally possible to detect neutral currents in processes such as: $$\bar{\nu}_\mu + e \rightarrow \bar{\nu}_\mu + e$$ What...
  20. D

    Semi-retired engineer, seeking knowledge of the greatest field in science

    I have a rudimentary understanding of classical physics and some (lesser) level of relativity and quantum mechanics. All came from undergrad studies before most of you were born. I tried to jump into the quantum world, only to find it necessary to relearn the basics of maxwells equations and...
  21. hyksos

    A Reflecting on null results in High Energy Physics

    For nine years, a discrepancy of the charge radius of a proton was a tantalizing hint at physics beyond the Standard Model. Recent experiments at York U in Toronto have shown that the discrepancy in the proton radius was likely due to a measurement error. Once again, High-Energy-Physics finds...
  22. geoelectronics

    I High Energy Physics: Positron-Electron Annihilation

    [Moderator's note: Post edited to remove the homework header.] High school physics demonstrations teach and show us that a positron and an electron must be at rest with their environment before they can join together and annihilate. The process makes them disappear and they are replaced by two...
  23. D

    Physics Are experimental high energy physics jobs this boring?

    Hello everyone. First of all allow me introduce my self briefly. I'm a guy from not that high progressed country of particle physics, and i graduated almost a year ago with degree of a bachelor in physics. I was a top student in my uni and got some prestigious scholarships. Just like many other...
  24. mjda

    I The Confinement Radius of a Cosmic Ray (Galactic vs. Extra-galactic)

    If we want to show whether or not a specific Cosmic Ray particle is confined to our galaxy we must use the Larmor radius (relativistic version), r = γmc / qB Considering a 10^14 eV proton and assuming the galactic magnetic field strength is 10^−11 T, show that the particle is confined to the...
  25. pallab

    Good books on Group theory in High Energy physics

    please suggest me a good book on the high energy physics where group theory is discussed for the beginner.
  26. e0ne199

    Good reference to learn high energy physics

    hello everyone, i just want to know about some good reference to learn high energy physics, maybe with some examples for real world practical application... and i heard that old books with this topic is far better than the new ones, can anyone here recommend a book or two? thanks before and i am...
  27. Q

    I How do we justify "Natural" Units

    How is it that when using "natural" units we drop the units themselves. I understand that you can arbitrarily change the magnitude of a parameter by choosing a new unit. For example Oliver R. Smoot is exactly 1 smoot tall. However, in natural units with [c]=[h/(2π)]=1 the "smoot" part is...
  28. A

    High Energy Recommended books in HEP, QFT, QM, GR

    Hi everyone! I'm trying to make a list of recommended books (introductory and advanced). So far, what I was able to search are the following: Particle Physics: - Griffiths: Introduction to Elementary Particles - Thomson: Modern Particle Physics - Nachtmann: Elementary Particle Physics -...
  29. A

    High Energy High Energy Physics and Group Theory Book Recommendations

    Hey there! I just want to ask if there are any books you would like to recommend that helps in studying high energy physics and HEP data analysis? Also can you recommend a good book for group theory and symmetry? I would be glad if you have links to free downloadable books. Thanks in advance!
  30. P

    Other Should I become the Physics lab coordinator for my university?

    Background: Physics and Math major, turning Sophomore from next semester. I worked for a professor during the summer (for free) in high energy Physics trying to plot the signals from a function generator to a computer using a microcontroller. He was really impressed with my work (basically, he...
  31. R

    Need career guidance for my masters in High Energy physics

    Hi I am graduating next year from the Univeristy of Athens Greece as a physicist so a moment has come where I have to make a big decision. I have already chosen the path of Theoretical High energy physics and I am currently working on my thesis which focuses on Q.E.D. My first ambition...
  32. Riotto

    A What are singular and double seesaw?

    I have just started reading about neutrino physics and recently came across two terms called double seesaw and singular seesaw. Although I’m familiar with other seesaw mechanisms (such as type-I and II) for explaining smallness of neutrino mass. I’m completely at dark about double and singular...
  33. Eslam100

    What are the topics in theoretical and mathematical physics?

    I'm a rising physics sophomore at a Japanese university. I've studied general physics, linear algebra, and analysis (actually, calculus of single and several variables with emphasis on analysis, everything was proven and the theoretical background was well explained) Other than that, I've...
  34. V

    A Building a synchrotron light source

    Lately, I've wanted to build a compact source of synchrotron radiation that is accessible to researchers with size and budget constraints. So far, I've managed to outline designs of the superconducting dipole magnets that will be used to keep electrons moving in a ring path within the booster...
  35. randomguy2335

    Schools UCB vs UCSD: Grad School & High Energy Physics

    Im debating between Berkeley and UCSD and I am not sure what to do, I plan to go to grad school, and I am worried that it might be difficult to get a lot of research done at UCB whereas I've heard its easier to get into research at UCSD. Furthermore I'd start a semester late at UCB because I...
  36. O

    B Is Dark Matter physics low or high energy physics?

    Is dark matter physics considered a low or high energy physics, and why?
  37. A

    Schools What is the best for an experimental particle physicist?

    I'm interested to become an experimental physicist particularly in particle physics. I have the chance to pursue a double degree. what is the best choice that will help me more in my future career.- a double degree in physics and computer science or a double degree in physics and material...
  38. H

    Studying Preparing for high energy physics MSc at ETH Zurich and Ecol

    Hello everyone! I was recently accepted into the High energy physics MSc at ETH Zurich (minor miracle...), doing the second year at Ecole Poly. This is after coming out of a BSc majoring in physics and maths, at a less prestigious uni which probably hasn't covered material to the same extent as...
  39. I

    A Software for symbolic calculations in high energy physics

    I interest the software, which understands gamma and sigma matrices, that the convolution can go over Lorentz indexs, and over group indexs, which understands what is covariant differentiation, trace. I tried to use maple, but work goes with difficulty. Although I write convolution over...
  40. ohwilleke

    I Are There Engineering Applications Of High Energy Physics?

    Beyond designing and operating particle accelerators are there any engineering applications of high energy particle physics* now or in the foreseeable future (e.g. next 20-40 years)? * i.e. the kind of interactions we are studying at LHC and Tevatron and in lattice QCD, as opposed to the kinds...
  41. B

    A Notation/Site for Representations of an Algebra

    I'm currently reading the paper "Higher Spin extension of cosmological spacetimes in 3d: asymptotically flat behaviour with chemical potentials in thermodynamics" I'm looking at equation (3) on page 4. I know that symmetrization brackets work like this A_(a b) = (A_ab + A_ba)/2. However I have...
  42. qqbar

    Peskin and Schroeder eq. 18.84

    Homework Statement So I am self-studying the book of Peskin&Schroeder, and there is something I don't understand on page 616. In eq. 18.80, there is a numerical factor of ½ and going from e2 to α will introduce a factor 4π when proceeding to eq. 18.84. But then there should be a numerical...
  43. P

    Programs How do I decide which sub-field of Physics I want to pursue?

    I'm a freshman at UT Arlington and I will get my undergraduate degree in Physics from that university. Now, I am sure that I want to pursue Physics, but not quite sure of the sub-field. I lean towards Astronomy a lot, and I will probably end up doing that. The problem is that my university...
  44. M

    Schools How good is the Ohio State University at high energy physics

    OSU ranks 31 according to ARWU-Physics-2015 and 25 according to US News/Physics. That sounds good enough, except for two facts which I want to be clarified. 1) According to gradschoolshopper.com the acceptance rate at OSU-Physics PhD in Fall 2015 was 35%, which seems quite high for a school of...
  45. S

    What are some topic areas in physics that I am interested in?

    I am senior physics undergraduate. I am interested in high energy physics, quantum entanglement and information as well as a little bit of astrophysics. I am applying to grad school this semester. Hope to get some help in grad school applications!
  46. I

    Any recommended summer school for high energy physics?

    Hi guys, my school will offer me an amount of money to have a summer exchange to do anything academic-related. I would like to apply for a summer school on HEP. Do there exist institute that offer summer program which specialized in HEP in the way similar to how Santa Fe Institute offer summer...
  47. Itrio39

    Master Degree in High Energy Physics in Europe: Find Universities

    Hello! I'm in my 3rd year of my bachelor degree in physics engineering and I'm thinking about taking a master degree in High energy Physics somewhere preferably in europe, could you recommend me some universities with a good program? Thank you
  48. Christian Grey

    Which theory or field can explain this?

    Suppose I am in a room and light(photons) from the light bulb reach my eyes, or I am outside light(photons) from the sun reach my eyes and I am able to see the objects around me. I want to know what factors affect the path of photons like temperature, gravity etc.I mean by knowing these factors...
  49. KylieVegas

    Programs Masters in physics without a different bachelors degree?

    Hello I am an incoming Biology student (college), i really wanted to take applied physics as my course but my parents told me that it is better to be a doctor, anyways, it's summer here and I started taking Calculus 1 in coursera.com (i have NO backgroud in calculus because we don't have...
  50. D

    PhD in Germany vs USA: IIT Roorkee Physics Student

    I am a final year Masters student studying physics at IIT Roorkee, India. I have PhD admits in experimental high energy physics from Karlsruhe Institute of Technology (KIT), Germany and University of Illinois Chicago, USA. I have previously done an internship as an undergrad with a professor at...