The Stack Overflow podcast is back! Listen to an interview with our new CEO.

Questions tagged [protons]

A proton is a positively charged particle which is generally considered to be a composite particle comprising of three quarks interacting through the strong force (e.g. in the standard model.)

Filter by
Sorted by
Tagged with
0
votes
1answer
29 views

How do you read the spin contributions of proton

This paper reads the number of their results. I'm attaching the how they have included all the spin contributions of quarks to proton. The contributions are from u, d, s quarks. How I can tell ...
0
votes
0answers
20 views

Is there a difference in wavelength emission spectra of ZnS:Ag when its irradiated with protons vs. gammas?

How would I measure this, because I couldn't find this information in literature as of yet? I have neutron (to produce protons by recoil) and gamma sources, but I don't have a pure neutron source, and ...
0
votes
0answers
14 views

Velocity of particles in electrolysis

In an electrolysis (H20) water is split up and the protons start to move towards the anode. So one would be able to calculate the acceleration of the proton from the electric field in that area. ...
18
votes
4answers
7k views

Can there be an atomic nucleus where there are more protons than neutrons?

As far as I know, number of protons is less that or equal to the number of neutrons in any atomic nucleus. But is there any possibility that there exists a nucleus where the number of protons exceeds ...
0
votes
0answers
5 views

Alternative symmetric spin + flavor part of a proton?

I have a doubt about the proton's quark structure. All sources I've read agree that the following is the quark structure of the spin-up proton (this one is from Griffiths' Introduction to Elementary ...
13
votes
1answer
335 views

How did we know that the Dirac equation describes the electron but not the proton?

I'm suddenly getting confused on what should be a very simple point. Recall that the $g$-factor of a particle is defined as $$\mu = \frac{ge}{2m} L$$ where $L$ is the spin angular momentum. For any ...
20
votes
4answers
1k views

How is the speed of nucleons in the nucleus measured?

This article claims that "nucleons in a dense nucleus exceed 25 percent of the speed of light". How do you measure or infer the speed of nucleons in the nucleus? Note added later: I'm looking here ...
36
votes
5answers
9k views

How do we know neutrons have no charge?

We observe that protons are positively charged, and that neutrons are strongly attracted to them, much as we would expect of oppositely charged particles. We then describe that attraction as non-...
0
votes
0answers
31 views

How much does the distance between electron orbits shrink as proton number increases?

I was watching a YouTube video that briefly mentioned the electromagnetic attraction between the nucleus and it's electrons increases as the proton count of an atom increases. I'd never considered ...
0
votes
0answers
16 views

How does positron emission happen naturally? [duplicate]

How does positron-emission happen naturally, for example in Potassium-40? Isn't the added mass of the neutron and the position more than the mass of a proton? Where does the proton get this extra ...
0
votes
1answer
60 views

Feynman diagram literature for antiproton production via proton-proton collisions

I'm looking for literature, or anywhere I can find a Feynman diagram, which describes the proton-proton collision where antiprotons are produced in the following reaction: $$\rm{p} + \rm{p} \...
2
votes
1answer
118 views

Can an electron be inside a proton?

This article has an image showing the 2S and 2P states of a hydrogen atom. The caption makes the following claim: The 2S and 2P states of hydrogen show where the electron could be found at any ...
0
votes
0answers
62 views

What is the theoretical charge radius of a proton?

Today I read this news article and this Wikipedia page that talk about the 'Proton radius puzzle', where discrepancies have been observed between values of the proton charge radius, when measured ...
-1
votes
1answer
49 views

Left and right handed electromagnetic radiation from different subatomic particles?

The acceleration of electrons in an antenna rod produces a radio wave with its oscillating electrical and magnetic fields. For a vertically oriented rod the electric field points up- and downwards. ...
1
vote
0answers
27 views

How do I estimate the endpoint energy for the proton?

How can I estimate the endpoint energy for the proton in the neutron beta decay? Following this answer, I can write the system of equation as: $$p_e+p_p+p_\nu=0$$ $$m_n=E_p+E_e+E_\nu$$ Assuming ...
1
vote
1answer
40 views

Synchrotron radiation for protons

I know that due to the huge mass difference and dependence of radiated energy on mass, protons lose much less energy in synchrotrons than electrons. Can someone tell me how to calculate the energy ...
0
votes
1answer
45 views

Thermodynamics of early universe - proton and neutron ratio [duplicate]

So, I have been reading about connection of particle physics and thermodynamics of early universe. Like after big bang, and quark - gluon plasma etc.. Anyway, after 1 second after big bang, the ratio ...
0
votes
1answer
19 views

How do I calculate how strong of a field I need to repel a proton in a span of time

How do I calculate how strong of a field I need to repel a single proton in a given span of time, given that I know it's velocity.
1
vote
1answer
77 views

Is a purely Electron or Proton bomb possible?

Since electrons repel other electrons and protons repel other protons, if you had enough of either of these in an enclosed space, and suddenly removed the enclosing barrier, would the repelling force ...
0
votes
1answer
32 views

Benefits and Drawbacks of Swapping Associations of Positivity and Negativity of the Proton and Electron

For historical reasons, I understand that a proton's charge was assigned the label of "positive", the electron's charge was assigned the label of negative, and, crucially, equations of current in E &...
1
vote
1answer
60 views

Producing a pair of pions

I know that two protons colliding at high energies can produce a pion $$p+p \rightarrow p+p+\pi^0$$ But is it possible for two protons to produce a pion pair? $$p+p \rightarrow p+p+\pi^{-}+\pi^{+}$$...
3
votes
2answers
72 views

How do we decide the proton wave function?

The fully symmetric spin-up proton spin-flavour wave function in the constituent quark model is usually presented as follows: $$\begin{align} \frac{1}{\sqrt{18}} ~ ( &2 |u\uparrow ~ u\uparrow ~ d\...
3
votes
2answers
446 views
1
vote
1answer
51 views

Recombination of hydrogen

Suppose a slow-moving electron and a slow-moving proton are injected into a chamber, such that the two approach each other and are likely to combine to form an atom of hydrogen. How would one ...
8
votes
4answers
2k views

Does a proton have a binding energy?

When calculating the $Q$-value, $Q = \Delta M \cdot c^2$, of this reaction: $$ ^6Li \ (\alpha, p)\ ^9Be \quad \iff \quad \alpha + \ ^6Li \ \longrightarrow \ ^9Be + p $$ The $Q$-value can also be ...
3
votes
1answer
88 views

Most of the momentum of a proton is carried by the quarks

I saw this in wiki https://en.wikipedia.org/wiki/Antiproton#Modern_experiments_and_applications "the valence quarks in the proton, and the valence antiquarks in the antiproton, tend to carry the ...
4
votes
2answers
92 views

Does an atom or proton (cosmic ray) get stretched when traveling through expanding space?

I have read this question: Why does space expansion not expand matter? I do understand that matter inside galaxies will not get stretched because inside galaxies, gravity dominates over dark energy. ...
2
votes
0answers
51 views

Are / Why are the H II regions positively charged?

One of the questions in our recent astrophysics course homework was to find the general opacity $\kappa$ of H II regions. We know that the H II regions are almost entirely ionized hydrogen and I ...
0
votes
0answers
36 views

Modelling Proton Beams using Numerical Methods

I'm attempting to model proton beams/proton therapy using numerical models in MATLAB. I'm having trouble tracking down the correct master equations to use to model beam energy (60-250MeV range) ...
0
votes
2answers
86 views

Limit to number of neutrons in nucleus [duplicate]

As far as I understand the number of protons in a nucleus is limited because Coulomb forces grow faster with the number of protons than the nuclear force. So alpha/cluster decay limits the size in ...
-1
votes
1answer
57 views

Would protons in a straight line ever break their alignment? [closed]

Let any amount of arbitrarily spaced protons appear along a line segment of length $x$ in an otherwise empty universe at $t+0$ What mechanism, if any, could cause the breaking of said alignment ...
2
votes
4answers
207 views

How much of the proton's mass is due to the Higgs field?

The proton mass is 938 MeV. People often claim that (A) The proton is a bound state of two up quarks and one down quark, with the three quarks contributing a total rest mass of $2 \times (2.2 \text{...
2
votes
2answers
79 views

What happens to the electron when a neutron knocks off a proton from hydrogen atom?

In recoil proton scintillators, the hydrogen acts as a neutron converter to produce protons when a neutron strikes a H atom. But what happens to the electron in H atom? Where does it go? Does it ...
12
votes
3answers
2k views

Why does the nucleus not repel itself? [duplicate]

If the nucleus is densely positively charged, why don’t the protons in the nucleus repel from each other and move towards the orbiting electrons? Because each proton is not only being repelled by the ...
3
votes
1answer
43 views

How would the structure function of protons be different if quarks had spin 0?

I saw this question in a practice exam. I know that the structure functions are not linearly independent but that $F_2(x)=2xF_1(x)$ when the energy is in the order of GeV. The question asks what ...
1
vote
0answers
69 views

Why does the conclusion that protons are monopoles has led us to believe that they specifically may have a half-life? [closed]

from Zeldovich, Ya. B.; Khlopov, M. Yu. (1978). "On the concentration of relic monopoles in the universe": "The majority of particles appearing in any quantum field theory are unstable, and they ...
0
votes
0answers
21 views

What devices are used in a proton accelerator to separate the protons from their electrons and send the protons into the vacuum chamber? [duplicate]

I understand the general idea of how they accelerate the protons once they get them isolated in the chamber, but what's the device they use to isolate them to begin with even called?
0
votes
1answer
31 views

Minimum energy of proton converting into a neutron

I'm given the isotope sodium 22 (which is positron emitter) and I'm stuck with calculating the minimum energy that a proton needs to convert into a neutron and a positron. It got to do with $E=MC^2$ ...
1
vote
1answer
140 views

Why protons and electrons attract each other? [duplicate]

This YouTube video states that electrons and protons are bonded together by emitting electromagnetic waves and absorbing each other's electromagnetic waves. But isn't because it due to potential ...
0
votes
1answer
50 views

Energy budget of of proton-proton fusion (p-p chain)

How much energy is released in the first nuclear reaction of the p-p chain which produces energy in lower-mass stars like the Sun? The value of 1.44 MeV is given in many sources, but I don't ...
18
votes
2answers
5k views

Why does this quiz question say that protons and electrons do not combine to form neutrons?

I read this somewhere: Where are the protons and electrons in a neutron star? When the neutron star forms, most of the protons and electrons combine together to form neutrons. But on a true/false ...
0
votes
1answer
51 views

What is the effect of isospin on the proton or neutron alone, i.e. not in a doublet?

So I start with a proton $p$. I extend my "physical" space by means of the internal degree of freedom of isospin, so that I know write $p$ in a higher dimensional space: $$ p = \left( \begin{array}{...
0
votes
1answer
47 views

How would a difference in electron and proton charge be detectable in astronomy?

How would a deviation in neutrality of matter affect astronomy? Obviously this would introduce a lot of repulsive force but how, exactly, would that affect the universe? If the repulsive force was ...
0
votes
1answer
46 views

Do electron really experience any repulsive force while attracted by proton compared to positron?

I read up that the reason 2 electrons with same energy states can be binded to the first orbital of a necleus is due to one electron having positive spin half and another having negative spin half ...
4
votes
3answers
127 views

Can you fake protons with light?

I have been reading similar discussions on how protons and electrons interact, using virtual photons and such. Yet, I can find little information regarding the subject in question. Can a beam of ...
0
votes
0answers
41 views

What is the upper limit for the size of an atom? [duplicate]

I read an article saying an Israeli scientist had discovered the heaviest nucleus with 122 protons and 170 neutrons, and found it in a sample of purified thorium, and I would like to know if there are ...
2
votes
1answer
90 views

Stability in Nuclear Shell Model

As far as I understand , a particular sub-shell is filled with either protons or neutrons, $2*(2l+1)$ number of them, and never both together since protons and neutrons fill up levels separately in ...
0
votes
3answers
101 views

formation of atomic nuclei from nucleons

What holds the nucleus together? In a nucleus there are several protons, all of which are positive. Why don't they push themselves apart? It turns out that in nuclei there are, in addition to ...
0
votes
0answers
51 views

Is there a mass spectrometer software that can measure the mass of a proton

I spent a lot of hours looking for mass spectrometer software (or Cathode-ray simulator) that can measure the mass of a proton or any sub atomic particle. Until now I only found software that work on ...
3
votes
2answers
611 views

Why is neutron slightly heavier than the proton? [duplicate]

With latest knowledge of QCD, is there any explanation for why the neutron is slightly heavier than the proton? Can it be boiled down to a simple formula?