Standard model Definition and 258 Threads

just looking at the standard model, which describes a host of fundamental particles and bosons, one could assume that the SM is a particle model. however, most of what i read appears to indicate that particles are merely "excitations" or manifestations of a field, and it has been stated on this...

http://nuclear.ucdavis.edu/~tgutierr/files/sml2.pdf Where is the = sign in this equation? Does it have one?

I'm trying to figure out where symmetry breaking occurs in Feynman diagrams. I'm just free wheeling here, correct me where needed. But as I understand it, when you have a Feynman diagram where there is an interaction of one particle which decays to others, the incoming particle may obey one...

Im reading Peskin&Schroeder, chapter 20, the one that describes the Standard Model. I got the general idea, symmetry breakings and so on, but I am getting quite confused when starting to go to the first mathematical details. My doubts are when, in eq 20.69 defines Q=T3+Y and then forces that...

Alright, so I'm just getting through my first semester of QFT and while I'm not quite ready to step into anything really heavy, I'm close to the point where I can read introductory material on a technical level (like, I could probably start Zweibach's Strings for Undergrads). I've been reading...

Maybe this is the wrong topic for this forum, but i am reading the following http://arxiv.org/abs/hep-ph/9703464 Which is on CPT violation and the standard model. I do not understand how they get to equation (9), when they write down the stress energy tensor as \Theta\mu\nu=1/2 i...

I was asked this question by someone else and wondered if I could get better answers here: Is it fair to say that the standard model for matter is basically descriptive, without any underlying understanding of what causes its structure? Can it be compared it to the periodic table of...

It's a bit premature to conclude the LHC won't find Higgs or SUSY but... There are a few ideas kicking around that use knots (braids, strings, strands, knotted dimesnsions or whatever) to "explain" the Standard Model. One that catches the eye for its explicit particle mass calculations is...

I know the Higgs has been causing some issues. Could we have a list of the problems/issues with the standard model, aside from the recent unverified neutrino issue. For instance, does anyone know where the spin of the proton comes from? Thanks

I'm confused about a premise implicit in the standard QM model of entanglement, which seems logically inconsistent. I understand that entanglement arises when two or more particles interact in some way to become synchronized in their quantum states, which also must be indeterminate in terms...

Something has bothered me for a long time about our model of light: that it has no mass. Just for a moment, forget what you know about light and let's call it the unknown, X, and suppose we want to model it. Here's what we know for certain: X has momentum, as seen by radiation pressure X...

The lambda-CDM model predicts a nearly flat spatial curvature at scales larger than the the scale of homogeneity of the universe. The calculation of many of its parameters depend on the cosmic distance ladder which in turn depend on many observational techniques and statistical comparisons...

The current state of NASA’s version of cosmology is amazing to watch – According to modern cosmology, which NASA endorses, the Milky Way is moving through space at 600km/s and the Earth is moving through space at 30km/s and the sun is moving through space at 250km/s. So if we total up these...

Some Questions on Lagrange Points – According to Wicki, a Lagrange point is The Lagrangian points are the five positions in an orbital configuration where a small object affected only by gravity can theoretically be stationary relative to two larger objects (such as a satellite with respect...

I'm a layman trying to understand the symmetries used in the std model. I understand that U(1), SU(2), & SU(3) are incorporated in the Lagrangians for internal symmetries. I've read that SO(3) is also used in the std model for Poincare spacetime symmetry. Is that true and if so, how is it...

What is the consensus here about Information Theory beyond the Standard model? The three fundamental theories of the universe, relativity, quantum mechanics, and the second law of thermodynamics all involve limitations on the transfer, accessibility, quantity, or usefulness of information...

A quick question from a non-physicist and non-mathematician. Do the equations of the Standard Model (without the Higgs Mechanism and any other speculative theories) presuppose that all the particles have zero mass and zero dimensions i.e. are they purely "mathematical" points?

Hi all - as everyone knows, the fundamental laws of the Standard Model are almost always presented in Lagrangian form. Can anyone tell me of anywhere (such as a textbook) that I might find the Hamiltonians corresponding to these Lagrangians written out? (I'm confused on a couple of points and...

I was hoping someone could point me in the direction of the best way to calculate the rest energy of a proton. I am a complete noob with the standard model, so please be gentle. My goal is to compare a calculation of the energy which accounts for the quark structure of the proton versus E=mc^2...

Cosmology's standard model: is science becoming a "belief"? I recently made a partially tongue-in-cheek remark on this board about cosmology being a bit like religion. I thought, being April Fool's day, that I might get away with a provocative post. However, it appears that others did not...

sort of a parallel thread to the current thread about "fields are more fundamental than particles". pretty much everything i have ever read about particles leads to the idea that what we perceive as particles is really just a manifestation of a field or of interacting fields. since we define...

So basically I need to do a project on a topic in "beyond standard model" can anyone give me any theoretically interesting topics? I know this is a very loose question, but .. p.s I am a 3rd yr undergrad so nothing to crazy Only topics i can think of are just a standard search for a...

It is sometimes stated that new principles are required to solve the puzzle of quantizing gravity and harmonizing all interactions. Let me first list some known principles - quantization of classical theories; not really a principle, but a "program" - equivalence principle in GR - gauge...

I was looking at a textbook on Introductory Nuclear Physics, and I came across this book: The Standard Model and Beyond By Paul Langacker http://www.taylorandfrancis.com/books/details/9781420079067/ It seems relatively complete. Anybody read this? Any thoughts/comments? What are other...

Perhaps if we focus on the common philosophy of the great physicists as to what physics is and ought be, expressed in their simple words reflecting infinite wisdom, we will be better prepared to advance physics beyond the standard model. Equations are more important to me, because politics...

Why can't we analytically continue our model of the Universe past the Big Bang in a way analogous to how the Euler sum is analytically continued into the zeta function? If this were possible, this extension would encompass a larger phenomenon but would reduce down to our Universe when certain...

Hello; I apologise for any typing errors, as I am typing from a handheld device. However, there is something that I do not understand about the standard model. I have read that this equation is a 'lagrangian' but I do not know what this means or how to work with one. According to what I...

http://articles.latimes.com/2010/jul/07/science/la-sci-proton-20100708 Like the article says, if this experiment is true, the proton is 4% smaller than originally thought. If true, doesn't this mean we have to throw out everything we think we know about particle physics (standard model...

I have spent a while trying to get to grips with the building blocks used for constructing feynman diagrams, below is my attempt at a set of reactions, how am I doing so far? I don't think e^{+}e^{-}\rightarrow\mu^{+}\mu^{-} can happen since a gluon only interacts on particles with a...

It is my understanding that the world of physics is split by a fast chasm into experimental and theoretical physics. The first time I told my father I wanted to be a physicist, he asked me “experimental or theoretical physics?” I thought for a second and responded “both!” He went on to explain...

A big part of the theory of the standard model is that the major forces are mediated by the exchanging of elementary particles. So hypothetically, if we discovered some material that blocked the photon, for example, does this mean an object wrapped in this material would be unaffected by the...

"Higgsless" Standard model I realize we haven't been able to see the signal for a Higgs boson directly yet, but I have heard there is plenty of indirect evidence for the Higgs (in that it is needed in the model to match experimental results). My question is essentially: are all forms of this...

I am looking for a decent book (probably a textbook) that covers the standard model in its entirety (not necessarily in its vast detail, though). I am a physics undergrad in my 4th year, so I'm looking for something that gets into specific math and theory, but obviously not something that would...

I've been reading most of the threads here in particle physics forum. Recently, I noted a couple of threads started by enotstrebor which were a bit impolitic. Nevertheless, they raised some issues which are similar to those I have myself with the Standard Model as well Quantum Mechanics in...

I am stuck on a few cosmological points I could use some help on. The first being "redshift" as an indication of inflation. To me red shift just seems like it's a result of the degradation of light quanta over long distances. Since light slows down in environments close to absolute zero...

Have loop quantum theorists looked forward to how one might fit the standard model into loop quantum gravity? Thank you for any help.

In the article "The Lattice Theory of Quark Confinement", by Claudio Rebbi (Scientific American) there is a graphic representing the chromoelectric field. The caption reads: "Chromoelectric field is a gauge field similar in principle to the electromagnetic field but more complicated...

The standard model comprises a particle model of reality, implying that every observable is either a particle of matter or a force carrying particle. QFT seems to imply that particles are merely manifestations of underlying fields - ie, particles are "ripples" in the field. if QFT is the...

Hello: The gauge symmetry of the standard model is written in authoritative places like wikipedia :-) as U(1)xSU(2)xSU(3). This would have 12 elements in its Lie algebra corresponding to one photon, W+, W- and W0 or Z, and the 8 gluons. I recall reading discussions that such a...

(I have a question about the Standard Model in spite of the topic title. It seems the right place to ask it after perusing the other forum topics. Also, I had erroneously posted this to the "Advanced Physics Forms" where the crickets are still chirping. It's not my intention to cross post...

Does anyone have a high resolution picture of the standard model lagrangian? i want to put it on a t shirt and give it to my math teacher who worked at Bell Laboratories for 10 years and knows just about everything about physics and math. P.S. i only think its called the standard model...

I'm trying to figure out what the standard model of particle physics is, what is included, who decides what's included, and how one would know when a new concept/theory is included or possibly rejected. It would be great to have a list of recent additions or experimental confirmations. Must...

A typical Scientist trying to get Standard Model to work. http://home.comcast.net/~erica.ramsey/StandardModelAndScientists.jpg

If you have doublet Q=(u,d) , and want to give the u-quark mass, you have to connect it to the Higgs VEV H=(\nu,0) doublet through the adjoint opertion: H^{\dagger i}Q_i Connecting H and Q through the Levi-Civita symbol e_{ij} : e^{ji} H_{ i}Q_j results in d-quark mass, not u-quark...

Is the Standard Model of physics more aligned with Bohm's or Bohr's interpretations? And if more aligned with Bohm, then why is the Copenhagen model so highly regarded and not Bohm's?

How does M theory force gravity as a necessity when the standard model couldn't fit in gravity?

When did beyond the standard model become an acceptable topic, and what has it added to our knowledge?

1. The Standard model is an SU(3)xSU(2)xU(1) symmetric theory. To me this means that if you choose any 3 members of the groups and act on the Lagrangian, it is invariant. However, not all terms in the Lagrangian have something for a group member to act on, for example terms that don't involve...

At this point, I am rather confused about the concept of DE, and even why it is called DE since it does not seem to fit into what the concept of energy is. but my question is where/how does DE fit into the standard model? thanks.

Hi guys, Where can i find the most up to date (accurate) values of the standard model coupling strengths at the mass of the Z boson? Thanks Karnten07