Particle physics Definition and 514 Threads

The composition of the π0 is (uu_bar - dd_bar/√2; while the composition of the η meson is (uu_bar + dd_bar)/√2. Why is there a - sign in π0 while is there a + sign in η? How are the signs determined? By the way, can I type Latex symbols on this site? I tried to type the anti up quark by typing...

This is a homework problem in a course in particle physics at Cornell University. Assume the Left Right Symmetric (LRS) model for leptons. The gauge group is GLR = SU(2)L×SU(2)R×U(1)X. The Standard Model group SU(2)L×U(1)Y has to be included in the LRS group. Namely, U(1)Y ⊂ SU(2)R×U(1)X. Find...

Hello everyone.. Myself Kaustov from NIT Trichy, pursuing BTech. in production technology. Very much interested to be a part of physics forum. I have knowledge on Theoretical Astrophysics and Cosmology and also Particle physics. Very much interested to be part of all the discussions and to help...

Homework Statement For the following theory: ##\mathcal{L}=\frac{1}{2}[(\partial \phi)^2-m^2\phi^2+(\partial\Phi)^2-M^2\Phi^2]+g\phi^2 \Phi^2## Compute s-channel amplitude for process ##\phi\phi \rightarrow \phi\phi##. Interpret result for ##M>2m##. Homework Equations Scattering amplitude...

I want to do a project using machine learning on the calorimeter event data of the LHCb. How can I access this data? Is it very difficult to navigate your way through the source code on your own?

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 -...

We often use SO(N) and SU(N) to describe symmetries in particle physics. I am not clear which one to choose when I try to discuss a symmetry. For example, why do we use SU(3) but not SO(3) to describe the symmetry of the three colors of quarks? Similarly, why do we use SU(2) but not SO(2) to...

In which fields of physics can we apply machine learning concepts? If I take data science master's with minor in particle physics or astrophysics, what are the possibilities that I would be employed as a physics related data scientist? (I am a programmer and I would like to change my career...

Hello! I wanted to ask why does the neutral Σ decay almost always to one γ(or two) and a neutral Λ. Why can't it decay to anything else? Thanks!

This is a question that I have tried to pose several times without any success but, anyway, I would like to try again for the very last time. Asume for a moment that EW-SSB (electroweak spontaneous symmetry breaking) actually happened in our early universe. Imagine that our Standard Model of...

How do we know the spin of an elementary particle? For example, a fermion has spin 1/2; a photon has spin 1; and even the ficticious graviton has spin 2. How do we know these spins? In other words, how are these spins determined?

Hi everyone! I am a high school student and I was wondering if anyone could provide some materials to help a high schooler study modern particle physics. I am interested in participating in the Beamline for Schools competition, which is where a team of high school students submits a proposal for...

1. Homework Statement ( This question is from the textbook of Introduction to Elementary Particle Physics, written by Griffiths, on the problem set of Chapter 3 ) Particle A (energy E) hits particle B (at rest), producing particles C1, C2, ...: A + B → C1 + C2 + ... + CN. Calculate the...

Hi, I found number 3 repeating in particle properties, like: a) 3 generations of matter: electron, muon, tau... b) 3 known charge abs values. (electron/pozitron +/-1, quarks: +/-2/3 and +/-1/3) c) Weindberg angle (~30deg) its 1/3 of right angle. Is there any other 3 hiding in particle...

When we look at those pictures of colliding particles in particle colliders, we see a large collection of curves and lines radiating out from the point of collision, representing the new particles which have been created. So two questions about this: 1) Why are these acting like particles in...

Hello! I read several times that those at CERN observe a new particle with a precision of 3-3.5 sigma and overnight (more or less) hundreds of papers in theoretical physics appear explaining the role of that particle and all its physics implication and after a while CERN announces that there was...

Homework Statement In a particle physics lab, an electron e− and a positron e+ collide, annihilate, and produce a W+ boson and a W− boson. Just before the collision, the electron and positron have a total energy of E = 100 GeV each, with velocities pointing along the +x-axis and -x-axis...

There's been talk about extracting Helium-3 from the Moon as a source of nuclear fusion energy because of it's efficiency and nonradioactive-ness--but I haven't seen anyone talk about any kind of side effects it could have either on the Moon itself, to people, etc. I understand because of it's...

I'm studying Quantum Field Theory and the main books I'm reading (Peskin and Schwartz) present Feynman diagrams something like this: one first derive how to express with perturbation theory the n-point correlation functions, and then represent each term by a diagram. It is then derived the...

Homework Statement Consider the process of decay of a muon into one electron, one electron antineutrino and one muon neutrino using the Fermi theory. Assume the matrix element is, ignoring the electron's and the two neturino's masses, |\mathcal{M}|^2 = 32G_F^2(m^2-2mE)mE being E the electron...

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...

Something curious is going on with these decays. LHCb gives a seminar talk Tuesday next week, a livestream will be available. Edit: See results discussed starting here I'll summarize the current status here. I tried to keep most at the advanced (I)-level, but I don't think that always worked...

Homework Statement [/B] The problem is as follows: in a reference frame there is one electron at rest and one incoming positron which annihilates with the electron. The positron energy is E and two gamma rays are produced. Find first the energy of the photons in the center of mass frame as...

Hi all, I recently flipped through a paper which got some press several years back, entitled "A Scenario for Strong Gravity in Particle Physics: An alternative mechanism for black holes to appear at accelerator experiments." There are a lot of speculative elements in the work, but the thing...

what does it mean that a particle is a pure eigenstate? could someone explain this to me simply ?

Homework Statement Show that integrated track length in EM-shower is proportional to ##E_0##. Homework Equations ##E(t)=\frac{E_0}{2^t}##, with radiation length, ##x_0##. Knowledge that shower terminates at ##E_c##. The Attempt at a Solution The total track length is naturally the total...

Homework Statement The energy of a daughter particle in electromagnetic shower is approximated by, ##E(t)=\frac{E_0}{2^t}##. Show that the energy falls off like approximately ##E^{-2}##, for small ##E##. Homework Equations Nothing really. Just a matter of knowing how to differentiate. The...

Homework Statement While not explicitly a homework question, I am having some trouble with deriving expressions for the center of mass energy in a fixed target experiment versus a collider experiment. The question is effectively, "Derive an expression for the center of mass energy in a fixed...

I am an undergraduate working in my university's high energy physics lab. I'm still new to particle physics, so I have to learn/understand a bunch of things on the fly. We are currently searching for a new state theorized to occur in a specific decay process. I know we have to work with data...

I am familiar with the following equation which relates weak isospin (T3) and weak hypercharge (YW): YW = 2(Q-T3) (Where Q is electric charge) However, while this can be used to calculate YW from T3 and vice versa, how do you calculate each of these properties individually, without using the other?

Homework Statement I am given the following interaction, $$\pi^-+p\rightarrow \pi^++\pi^-+n,$$ and asked to draw the Feynman (quark flow diagram). Homework Equations None; just baryon number conservation, quark flavor conservation, etc. The Attempt at a Solution First, as baryon number and...

In supersymmetric extensions of the standard model, the neutralinos and charginos (popular candidates for dark matter) are often included. However, it is known that these fermionic particles are linear combinations of supersymmetric bosinos (such as gauginos and higgsinos). Therefore, it seems...

I am hoping and I would most appreciate that one or more PF participants will be able to help me find out the following, either by posting answers or citing useful references. 1. What types of particles are candidates for being DM stuff? 2. For any of these candidates, are there estimates of...

Hello! I have the equation FM = qvBsinθ . As the end result, I am trying to figure out what B I need to change θ even a little bit. To do that, I was planning to find the minimum B by differentiating B=(μe/4π)(qv x R / R3) in terms of R and setting it equal to zero. . I am assuming that this...

Hello! Can someone please recommend me a particle physics book that starts from the very basic concepts, but gives complete proofs for everything (for example, I want to start with the "spinless" particles interactions as an introduction to Feynman calculus, but I don't want them to just write...

I'm currently a junior in high school, and I'm really interested in physics, especially particle physics and quantum mechanics. At my school, everybody needs to do a big senior project to graduate, involving multiple papers and about 30 hours of work, usually to build something or organize a...

Just found this new book on amazon. Looks interesting. I purchased. https://www.amazon.com/dp/0691167591/?tag=pfamazon01-20 The TOC, Preface, and intro could be found here http://press.princeton.edu/titles/11050.html I wish they included a sample chapter as well (the book in not cheap), but I...

I'm a freshman physics major at a small research university in Philadelphia. The majority of the university is geared toward the health sciences, so we have very limited opportunities for research in physics. I'm just starting to develop my interests in specific fields in physics, and I'd...

Hello. I'm actually taking Ph.D. course for plasma physics and I think I'll finish this course within this year. I took classes in quantum field theory and general relativity in last semester luckily and experience of these subject ignited a desire to study theoretical particle physics and...

Hello there, I have always loved physics and wanted to get a degree in physics, particularly particle physics. But my father told me that if i have a physics degree i won't be able to get a job easily so i should pick an engineering course instead. i looked through engineering types but i...

What are the main maths used in the mentioned fields of physics? Not just general terms like "Calculus" but more specific maths. Also, what is the logic behind using these to solve problems in physics? Example, why would someone use differential calculus to calculate the probability of a...

Hello Everyone, While deriving potential energy stored in space due to two stationary opposite charges we end up with negative value of energy which upon dividing by c square provides us with negative value of mass. What is the significance of this mass other than reducing the total mass of...

I am trying to figure out what winfield oh physics i should study for a career. I absolutely love learning about strange quantum phenomena but also love learning about extremely small particles and how they interact at the smallest of scales Would i be interested in a career in particle physics...

I'm a Nuclear Physics student and I'm finishing the university in this period. I was searching for a PhD in Particle Physics but I don't know where to go, anyone knows some interesting school to make an application? Thanks

Hi everyone, I have the following question When a positive pion interacts with a proton, a kaon can be produced, along with another strange particle, as shown in this equation \pi^++\textrm{P}\longrightarrow \textrm{K}^++\textrm{X} Circle the type of interaction shown...

Hello folks. What math do I need to understand books talking about quark-antiquark pairs, the Higgs field, and the Standard Model?

Hi :) Does the 'inner space' and 'inner particle physics' which Mr. Lisi refers to in his TED Talk at Maui in 2013 refer to the 8 dimensional maximal tori within E8 and how they function? TED Talk at Maui in 2013 (video): Thanks.

Question: Draw the lowest-order Feynman diagrams for the e+e- --> W+W-process The answer gives three diagrams. I understand the first two, but the third makes no sense to me. Here it is: So this is a t-channel Feynman diagram. As far as I can tell regarding how these types of Feynman diagrams...

Hello! Is there any rule to do sums and products like the one in the attached picture (Lie.png) without going through all the math theory behind? I understand the first (product) and last (sum) terms, but I am not sure I understand how you go from one to another. Thank you!

We know that pions can be produced through decaying of kaons via weak interaction, but we also know in the acclerator the pions can be produced in pair via strong interaction. So my question is pions are produced via both strong and weak interactions?