# Tagged Questions

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 ...

22 views

### How does gauge invariance protect the SM gauge boson masses in SUSY from divergent radiative corrections?

The W and Z gauge bosons receive radiative corrections in loop from the heavy SUSY scalars. There is an argument using gauge invariance which explains how the masses remains protected. I am not able ...
52 views

### What would be the masses of the elemental particles if the Higgs field had a different value?

Afaik there is some function, for example, for the mass of the electron $m_e(\phi_1, \phi_2, \phi_3, \phi_4)= ...$, and similarly to the other elemental particles. (Here the $\phi_{1..4}$ are the ...
109 views

### Sufficient conditions for a interaction to be classified as weak, strong, …?

Let us say I have been given the equation of a interaction/decay/etc. between particles: $$X+Y\rightarrow A+B$$ Are their any sufficient conditions that we can use to determine the type of interaction ...
36 views

### Flavour basis to mass basis

I am not really understood why we need to change the basis from flavour basis to mass basis after Spontaneous symmetry breaking applying to Yukawa Lagragian? why we can't take (or not making ...
22 views

### Problems with the strong interaction and the rest of the standard model [duplicate]

This question has been heavily revised from what I asked earlier: Michio Kaku, in his QFT a Modern Introduction says (in paraphrase) that the $SU(3)$ gauge symmetry of the strong interaction must be "...
51 views

### What does Michio Kaku mean when he says that the Strong Interaction must be “penciled in” to the Standard Model [closed]

This is a very heavily revised question asked earlier: Michio Kaku, in his QFT a Modern Introduction says (in paraphrase) that the $SU(3)$ gauge symmetry of the strong interaction must be "penciled ...
73 views

### How does one write the standard model Lagrangian in other smaller Lagrangian counterparts?

How does one write the standard model Lagrangian in other smaller Lagrangian counterparts? Before electroweak symmetry breaking by the Higgs Mechanism: $L_{EW} = L_{g} + L_{f} + L_{h} + L_{y}$ Where ...
375 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 ...
330 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 ...
362 views

### Do all the particles acquire mass in the Standard Model due to the Higgs mechanism only?

I know that a mass term for an intermediate boson is not compatible with the gauge symmetry. But in principle a mass term for the electron field does not violate a gauge symmetry. However to build an ...
86 views

### Why neutrino is always left handed

Why all neutrinos are always left handed while all anti-neutrinos are right handed.
38 views

### How do the right-handed fermions acquire mass?

I am constructing a presentation on how elementary particles acquire mass via interaction with Higgs field. I asked this question previously in a different form and received the usual clap trap, so I ...
30 views

### Influence of matter of a star on masses of neutrinos

It is well known that if neutrinos has masses then from Dirac equation it follows that they propagate (in vacuum) as a eigenstates of mass (not as eigenstates of interaction). It's wave function is of ...
36 views

### How do force carrying particles “give” force? [duplicate]

So, I am not taking physics in school, but I do have an interest in it, and I was wondering, in the standard model, all of the force carrying particles (photons, Z Bosons, W Bosons, gluons, and (...
508 views

### Strange modulation of radioactive decay rates with solar activity

Recently I found out this strange article about nuclear decay rates somehow showing seasonal variations with a high correlation with sun activity. Has this been experimentally confirmed/disproved? ...
12 views

### Selection Rules in FCNC mediated diagrams

I am studying the flavour changing processes mediated by flavor changing neutral current (FCNC). Are there any selection rules involved in assigning the flavor to the outgoing quark? Can the ...
31 views

### Constructing singlet from doublets

Can we construct a gauge invariant term using the SU(2) doublet $l_L=(\nu_e e)^T$ and $(l_L)^c=C\bar{l}^T_L$? Since, both are doublets under SU(2), and $2\times 2=3+1$, I wonder what will be the ...
46 views

### Lagrangian of Yukawa Interaction and Quark Mixing

I'm trying to understand the original of quark and lepton mass. Here's a paragraph from the book: "Massive neutrinos in physics and astrophysics" by R. N. Mohapatra and P. B. Pal : The gauge ...
43 views

76 views

### What is the cause of the minor mass difference between the proton and the neutron?

As known, the proton is from two up and a single down quark, while the neutron is from a single up and two down quarks. The down quark is a little bit more massive and the up, and so the neutron is ...
89 views

### What makes neutron heavier than a proton? [duplicate]

The mass of proton is 1.672*10¯²7 kg while it is 1.675*10¯²7 kg. Both are made up of 3 quarks each. Then what makes proton lighter than a neutron?
284 views

### How it is possible to mediate a weak interactions by very heavy particle such as Boson?

When considering a weak decay interaction such as leptons , the weak force is mediate by huge particle such as bosons (W+ or W- ). How it is possible to have a such heavy particle within less massive ...
185 views

### How does the Higgs field provide mass to the known elementary particles and does even thinking about amplitude and frequency have any bearing on it?

One of the first things I was looking for when I found this site was a clarification on what an increase of mass/energy is when Matt Strassler was using the analogy of tightening a spring and applying ...
75 views

### Understanding type of force interaction in particle decays

Are there any fundamental rules of thumbs that can be used to identify the type of force interaction (weak, electromagnetic, strong) in a particle decay without drawing the Feynman diagrams at the ...
69 views

### Why do we need $SU(2)\times U(1)$ invariant mass terms if the symmetry will be broken anyway?

In the SM we can not add fermionic mass terms like $m \overline{e}_R e_L$ to the Lagrangian since these terms are not invariant under $SU(2)\times U(1)_Y$. After introducing the Higgs in the unitary ...
67 views

### If we were able to manipulate enough energy, could we use the higgs field for any practical application? [closed]

My question is, the fields in the standard model interact with each other, and when we are able to manipulate some of them through different engineered devices, we can transform the energy field into ...
56 views

### Is there scale invariance in the region of QCD aymptotic freedom?

It is said that in the deep inelastic scattering, scale invariance emerges. In the scattering of electrons off protons, this reflects the asymptotic freedom. Now I got a question. Normally, a system ...
335 views

### Why is there no fundamental force following from the $SU(4)$ symmetry?

I've understood that the three fundamental interactions described by the Standard Model (the electromagnetic, the weak and the strong force) are thought to correspond (roughly) to gauge invariances ...
58 views

### Is it possible the weak force isn´t fundamental? [closed]

Once the strong force was thought to be a fundamental force mediated by the massive pion. Later colour and gluons were introduced. The old strong force was a residue force of the new fundamental force....
1k views

### How many kinds of “weak charges” exist?

For electricity, we have one charge, for the strong force three. How many are there connected to the weak force? Three, because of the W- and Z-particles?
71 views

### Ambiguity in assigning intrinsic parity

We know that, fermions can have intrinsic parity either $\eta_P=+1$ or $=-1$. How does one then fix the intrinsic parities ofthe elementary particles, uniquely? Again, the intrinsic parity of a baryon ...
27 views

### Where do the intrinsic parities of particles come from?

It is known that some particles have negative intrinsic parity - for example pion $\pi$. I was wondering if this parity can be understood. I read somewhere that parity of quarks is defined to be ...
51 views

### How does quark color affect the identity of a hadron?

I've read about colors relating to quarks and hadrons and I know that they can change colors because of the exchange with gluons, but does changing color change the type of hadron? Does a proton ...
427 views

### Can superpositions of baryons with different electric charge and strangeness exist?

I am trying to find out whether the following baryons can exist: $$|X\rangle = \frac{|u u u\rangle + |d d d\rangle + |s s s\rangle}{\sqrt{3}}$$  |Y\rangle = \frac{|u u u\rangle + |d d d\rangle - ...