A model of the basic particles and forces featuring six quarks, three charged leptons, three massless neutral leptons and four fundamental force carrying bosons. The twelve fermions are arranged into three generations, while the bosons serve to explain the electromagnetic interaction plus the strong ...
3
votes
1answer
287 views
Why is mass renormalization insufficient to explain electron mass?
In the Standard Model, I understand that the mass of the electron is assume to arise from two effects:
A bare mass given by Yukawa interaction with the Higgs field, and
A mass correction from mass ...
2
votes
4answers
163 views
Computer Science Modeling of Physical World
I am curious what efforts have been made to date to define virtual computer worlds based on the physics we know in the real world?
I think it would be awesome to say start off with an atom defining ...
3
votes
1answer
262 views
What is the hierarchy problem?
BACKGROUND
So far I understood that the hierarchy problem was the large difference between the gravitational scale, $M_{pl}\sim 10^{18}\; [GeV]$, compared with the electroweak scale, $M_{ew}\sim ...
3
votes
1answer
239 views
Relationship between hierarchy problem and higgs fine tuning?
I often hear of hierarchy problem being used synonymous with Higgs fine tuning (esp with regards with motivations for SUSY). What exactly is the relationship between the two problems? As I understand ...
6
votes
1answer
187 views
Weinberg angle measurement methods
I was reading up on the history of $W/Z$ bosons today and I got a little puzzled. I always assumed that people measured $M_Z$ and $M_W$ and then derived the Weinberg angle. But it appears that they ...
5
votes
2answers
251 views
Was the Higgs mass correctly predicted by asymptotic safety of gravity?
This paper was published in Phys Lett B in 2009, and predicted the Higgs mass to be 126 GeV based on the asymptotic safety of gravity. Is this prediction taken seriously by the theory community, or is ...
7
votes
1answer
110 views
Is the LEP B meson asymmetry evidence for higher dimensions and/or string theory?
According to this blog, new standard model calculations have changed the 3 sigma B meson forward and backward production asymmetry observed at LEP into two anomolies:
A 2.5 sigma B meson production ...
4
votes
3answers
230 views
Do strong and weak interactions have classical force fields as their limits?
Electromagnetic interaction has classical electromagnetism as its classical limit. Is it possible to similarly describe strong and weak interactions classically?
2
votes
2answers
198 views
Fermion Field of Standard Model
Why fermion field is treated as anti-commuting and boson field as truly classical in standard model?
3
votes
1answer
98 views
Weak isospin confinement?
According to the Wikipedia article on color confinement:
The current theory is that confinement is due to the force-carrying gluons having color charge [...],
i.e. because the gauge group is ...
3
votes
1answer
234 views
What's the deepest reason why QCD bound states have integer charge?
What's the deepest reason why QCD bound states have integer electric charge, i.e. equal to an integer times the electron charge?
Given that the quarks have the fractional electric charges they do, ...
1
vote
2answers
251 views
Quark compositions in $\pi^+$ to $\pi^0$ pion decay
Pions can undergo a rare beta-like decay into leptons:
Pion beta decay (with probability of about $10^{−8}$) into a neutral
pion plus an electron and electron antineutrino (or for positive
...
-6
votes
2answers
245 views
Cramer's rule, Origin of Quarks Fractional electric charge? [closed]
In linear algebra, Cramer's rule is an explicit formula for the solution of a system of linear equations with as many equations as unknowns.
2u+1d=1
1u+2d=0
$$a_1d+b_1u=c_1$$ $$a_2d+b_2u=c_2$$ ...
-4
votes
1answer
228 views
Pion Decay and Fractional electric Charge disappeared, why?
Since the charged pions decay into two particles, a muon and a muon neutrino Fractional electric Charge disappeared, why?
The decay proceeds by the weak interaction $W^{+}$ and can be visualized in ...
-7
votes
2answers
435 views
Could the fractional model of Quarks electric charge turn out to be false? [closed]
The delta baryons (also called delta resonances) are a family of subatomic hadron particles which have the symbols $\Delta^{++}$, $\Delta^{+}$, $\Delta^{0}$, and $\Delta^{−}$ and electric charges +2, ...
0
votes
1answer
264 views
What is the relationship between the Higgs field and quarks?
I have some difficulty considering the relative size of each and the meaning behind the shape of Higgs boson. I ask relating to the structures of both the Higgs field and quarks. How is it that the ...
0
votes
1answer
56 views
What mechanism produced the baryon excess in the universe?
A baryon is a composite subatomic particle made up of three quarks (as distinct from mesons, which comprise one quark and one antiquark). Baryons and mesons belong to the hadron family, which are the ...
0
votes
0answers
115 views
Electroweak Symmetry Breaking
Electroweak symmetry breaking is manifested by the nonzero masses of the weak W and Z bosons, and requires the existence of a Higgs boson or some other yet unseen mechanism. To solve the problem of ...
1
vote
1answer
101 views
Why does the running of the gauge couplings show $\frac{1}{\alpha}$ > $\frac{1}{\alpha_w}$ at low energy?
I thought the coupling constants were something like:
$\alpha \approx 1/137$
$\alpha_w \approx 10^{-6}$
$\alpha_s \approx 1$
And yet if you look at any pictorial representation of the running of ...
2
votes
5answers
247 views
Could Quark model turn out to be false?
Quarks combine to form composite particles called hadrons, the most stable of which are protons and neutrons, the components of atomic nuclei.
Due to a phenomenon known as color confinement, quarks ...
5
votes
3answers
224 views
Higgs Boson: The Big Picture
First, please pardon the ignorance behind this question. I know a fair amount of math but almost no physics.
I'm hoping someone can give me a brief "big picture" explanation of how physicists were ...
3
votes
2answers
93 views
What exactly is the weak portion of the SM gauge group?
This Wikipedia article: http://en.wikipedia.org/wiki/Left%E2%80%93right_symmetry states that the weak part of the SM gauge group is not $SU(2)_L \times U(1)_Y$ but $ \frac{ SU(2)_L \times ...
6
votes
1answer
332 views
Anti particles: What exactly is inverted?
http://en.wikipedia.org/wiki/Antiparticle says "Corresponding to most kinds of particles, there is an associated antiparticle with the same mass and opposite electric charge."
and
What is anti-matter?
...
3
votes
3answers
240 views
If the electron is point like, then what is the significance of the classical radius of the electron?
What is the physical meaning/significance of the classical radius of the electron if we know from experiments that the electron is point like?
Is there similarly a classical radius of the photon? The ...
1
vote
4answers
844 views
Why is Neutron Heavier than Proton?
This is Neutron decay:
$$n^o \to p^+ + e^- + \overline {\nu_e}.$$
and this is proton one:
$$p^+ \to n^o + e^+ + \nu_e$$
so when the $e^+ =e^-$ and $\nu_e=\overline {\nu_e}$ why $n \not= p$?
my ...
6
votes
3answers
418 views
How are the masses of unstable elementary particles measured?
I am interested in knowing how (Q1) the particle's masses are experimentally determined from accelerator observations.
What kind of particles? They must be as far as we know elementary and unstable ...
0
votes
0answers
95 views
What would the universe be like if Electroweak symmetry were unbroken? [duplicate]
Possible Duplicate:
What happens to matter in a standard model with zero Higgs VEV?
What if the Higgs did not have a "Mexican hat" potential and the therefore it's vacuum expectation value ...
2
votes
2answers
263 views
Some very basic questions on the Higgs Boson
What exactly is a boson?
Is the Higgs boson the cause of gravity or a result of it? Does the collision of particles at the LHC create a gravity field or waves or somehow interact with the gravity ...
4
votes
0answers
111 views
Relation among anomaly, unitarity bound and renormalizability
There is something I'm not sure about that has come up in a comment to other question:
Why do we not have spin greater than 2?
It's a good question--- the violation of renormalizability is linked
...
1
vote
1answer
118 views
Lepton masses in the Standard Model
Some simple questions regarding leptonic masses in the Standard Model (SM):
Why there is not an explicit mass term in addition to the effective mass term that arises from the Yukawa terms after ...
1
vote
0answers
50 views
Is there mathematical proof of the vectorial character of the strong and em forces?
In a old paper,
http://arxiv.org/abs/hep-th/9509163
Becca Asquith argues that it is possible to prove that if the SU(2)xU(1) sector of the standard model is chiral, then the SU(3)xU(1) sector is ...
2
votes
1answer
277 views
Is Connes model a composite Higgs in disguise?
Most of the 5-dimensional Higgs models can be seen, if I understand correctly, as models where the Higgs is a composite.
Now, is this true for Connes models? It is a model of extra dimensions too, ...
2
votes
2answers
98 views
Charges of quarks and leptons
Are there any theoretical restrictions within the framework of QFT that fix the relative sign between charged leptons and up-type quarks?
We know that in our universe, they have opposite signs -- ...
1
vote
1answer
293 views
Quark Radius Upper Bound
If quarks had internal structure (contradicting current beliefs), what is the lowest
upper bound on their "radius" based on current experimental results?
If possible, I'd prefer to only consider ...
3
votes
0answers
271 views
On the naturalness problem
I know that there are several questions about the naturalness (or hierarchy or fine-tunning) problem of scalars masses in physics.stackexcange.com, but I have not found answers to any of the following ...
3
votes
3answers
390 views
Does every elementary particle have its own separate field?
Higgs field is pretty simple for me to understand, you have one field that creates one particle (Higgs boson).
So I continue to assume one field one particle.
Up field creates a up quark.
Down field ...
4
votes
0answers
105 views
What is the rate of B violation expected in the standard model during high energy collisions?
In a recent question Can colliders detect B violation? I asked about detecting B violation in collisions. Here I am interested in the theory aspect. (I asked both questions originally in the same ...
5
votes
2answers
228 views
How does Annihilation work?
I'm wondering why matter and antimatter actually annihilates if they come into contact. What exactly happens? Is that a known process? Is it just because of their different charges? Then what about ...
2
votes
1answer
217 views
Higgs potential
The potential for the Higgs field is standard a quartic one (Mexican hat). Is this done for simplicity or are there fundamental reasons for this choice? I can imagine further contributions to this ...
1
vote
3answers
168 views
Neutron decay and electron anti neutrino $n\to p + e + \bar{\nu}_e$
Why do we need neutrino to explain neutron decay?
Is there any evidence regarding existence neutrinos in the context of
$n\to p + e + \bar{\nu}_e$?
4
votes
2answers
179 views
What has been measured at the Higgs experiment and what do we know now?
Explained at the level of a 5$^{\text {th}}$ semester physics student (i.e. pre QFT, but far beyond the level of a news article for non-physicists, which avoids all details and only deals in ...
-4
votes
1answer
153 views
Why did Standard Model never sense a requirement to include gravitational quantum?
Standard Model is advanced version of Quantum physics. It tried to include everything which came in the way while understanding quantum world. It even didn't bother to include even Higgs Boson which ...
3
votes
3answers
257 views
Does Standard Model confirm that mass assigned by Higgs Mechanism creates gravitational field?
I am not comparing passive gravitational mass with rest inertial mass. Is there an evidence in Standard Model which says that active gravitational mass is essentially mass assigned by Higgs mechanism.
...
0
votes
1answer
153 views
How to calculate Rest Mass practically with Standard Model?
With relativistic physics, we can apply force to see resistance against acceleration. It'd give us relativistic mass and we have well established formula to get to the Rest Mass as long as we know the ...
3
votes
2answers
497 views
Does Dark Matter interact with Higgs Field?
Dark matter does have gravitational mass as we know from its discovery. Does it have inertial mass?
3
votes
1answer
90 views
Would the Standard Model allow two energetic photons to form a particle-like, zero-spin resonance?
The title is the question: Would the Standard Model allow two energetic photons to form a particle-like, zero-spin resonance?
4
votes
2answers
383 views
Is the Higgs a quantum field or a particle?
The Higgs is not detected in the asymptotic data, so it is possible that there is no particle interpretation for the Higgs quantum field. Indeed, the Higgs potential is only positive definite if the ...
0
votes
0answers
50 views
Which higgless models still predict a higgs-like resonance below the TeV scale? [closed]
Given today's announcement, I assume a bunch of wikipedia pages will need editing! The question is, which ones? Which higgless models still predict a resonance similar to the one observed by the ATLAS ...
1
vote
1answer
170 views
Why not accurate masses of elementary particles?
In the standard model of particle accuracy in calculating mass is very low.
And you can not predict the upper limit of Higgs particle mass accurately. Why not accurate masses of elementary particles?
1
vote
1answer
238 views
Why are all observable gauge theories not vector-like?
Why are all observable gauge theories not vector-like?
Will this imply that the electron and/or fermions do not have mass?
How is this issue resolved?
Background:
The Standard Model is a ...
