Particle physics is the study of the fundamental forces of nature as they are embodied in the interactions of elementary and composite particles at high energies and short time and distance scales.

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Mirror Matter Hypothesis?

What is the current state of the hypothesis of mirror matter today? Are there any experimental data or theoretical arguments that exclude it by now, or is it still considered viable among physicists? ...
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104 views

Convolving Parton Distribution Functions

I have the cross-sections as a function of $\sqrt{s}$ for a process with a $u$-quark and $u$-antiquark in the initial state (eg.: $u \bar{u} \to e^- e^+$). I have a standard parton distribution ...
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446 views

What particles carry various forms of energy?

If I didn't get this wrong, light or heat energy consists of photons and they in turn effect electrons' behavior and thus responsible for chemical and electrical energy. What kind of similar particle ...
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Quantum mechanics - how can the energy be complex?

In section 134 of Vol. 3 (Quantum Mechanics), Landau and Lifshitz make the energy complex in order to describe a particle that can decay: $E = E_0 - \frac{1}{2}i \Gamma$ The propagator $U(t) = ...
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1answer
120 views

How to determine predicted CP violation for a given SUSY point?

I'm currently studying at the spectra of some supersymmetric models, and would like to know whether the parameter points I'm looking at are ruled out due to excessive CP violation. I am using SPheno, ...
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175 views

Exploiting the Heisenberg Uncertainty Principle as a means to communicate

It seems as though I've come across a rather unusual conclusion that could either simply be a misinterpretation or a contradictory discovery. I seem to have found a way to utilize the Heisenberg ...
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106 views

Final-state baryons in $p \bar p$ collisions in Pythia

I'm trying to simulate inclusive $\chi_c$ production in $p \bar p$ collisions at very low energies (~ 5.5 GeV) using Pythia8 event generator. Leaving aside problems bounded with applicability of ...
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2answers
1k views

How deep can my knowledge of particle physics go without the maths?

By no means do I have the mathematical background to understand most of the math used in elementary particle physics. My current knowledge is of all the elementary particles and how they interact ...
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2answers
630 views

So there are 6 quarks, what are anti-quarks considered then?

I just recently got into particle physics and the quantum world and I love it. So my first big question is. I watch all these videos and people explain the quarks (up, down, top, bottom, strange, ...
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110 views

Can Joule's First Law of Thermodynamics be Applied to Atomic Charges?

James Joule established that all forms of energy were basically the same and interchangeable. My question is if thas law is relevant in particle physics. Can a positive charge and a negative charge be ...
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83 views

Minimum $E$ of $p\bar{p}$-collision for $q\bar{q}$ pair with mass $m_q$

I am currently working out the energy required to create a particle anti-particle pair from a collision of a proton travelling along the x-direction with an anti-proton which is at rest. The particle ...
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1answer
364 views

Did the Feynman heuristic of “simple effects have simple causes” fail for spin statistics?

Someone here recently noted that "The spin-statistics thing isn't a problem, it is a theorem (a demonstrably valid proposition), and it shouldn't be addressed, it should be understood and celebrated." ...
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4answers
250 views

Why are electrons consider waves?

I know the wave nature of electrons was evoked to explain why atoms are stable but I thought waves could be put in the same state like photons yet electrons can not exist in the same state.
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706 views

Do neutrinos of any flavor get trapped in black holes?

This question has been bothering me a bit. I know that neutrinos have super small mass and they interact via the weak force. Since they have a non-zero mass, they should be affected by black holes and ...
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2answers
656 views

If helicity can suppress weak decay of $\pi^{\pm}$, doesn't that make chiralty observer dependent?

I have been under the impression that chirality is at least in part a way to sneak in a Lorentz invariant version of helicity for particles that mass. Flip Tanedo seems to espouse this view in a ...
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139 views

Are oscillations of electron chirality experimentally observable?

Is there any plausible experiment by which chirality oscillations in electrons could be observed experimentally, such as through some analogy to neutrino oscillation experiments?
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1answer
955 views

Origin of electric charge

Baryons have charges that are the result of a polynomial calculation of their building blocks (quarks)'s fractional charges. But what gives these quarks electric charges? What interactions do they ...
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1answer
537 views

Dirac magnetic monopoles and electric charge quantization

Wikipedia describes how assuming the existence of a single magnetic monopole leads to electric charge quantization. But what if there's more than one? The same argument would apply to each of them ...
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2answers
220 views

Why is electron presented in books, pictures as a sphere?

Why is electron presented in books, pictures as a sphere, when in fact it's not?
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1answer
258 views

Dalitz plot analysis

I have seen a few Dalitz plots so far and tried to understand how they are useful. So one of the advantages of these plot is that the non-uniformity in the plots can tell something about the ...
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3answers
517 views

Quantum field theory, particle interpretations and path integrals?

I am trying to find some names or models of a particle interpretation of quantum field theory which isn't a literal path integral approach? Are there any particle interpretations of quantum field ...
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227 views

Why is there a linear relationship between charge and isospin?

So the title basically says it all. Something that's really bothering me is the fact that the Gell-Mann Nishijima relationship can be extended to provide a linear relationship between charge and all ...
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1answer
201 views

What algorithms are used for track reconstruction in cloud chambers?

In particular I'm interested in any algorithms that can separate multiple tracks from one another reliably.
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52 views

What causes the mass of Higgs boson itself? [duplicate]

Current theories stipulate that particles mass is due to : Quantum chromodynamics (mutual attraction of quarks, i.e. gluon's kinetic energy, circa 98%) and Higgs field (quarks rest mass, circa 2%) ...
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199 views

Does the unpredictability in the “micro world” means that everything is if we can look at it close enough imperfect?

Does the unpredictability in the "micro world" means that everything is if we can look at it close enough imperfect? I mean, there is a saying "You will never stand in the same river again" or ...
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1answer
369 views

Where do positron and electron get K.E from in Pair production

In pair production, we get a positron and electron from a photon. The photon should have 1.02Mev energy to carry out this process When the energy of positron and electron is added, we get the energy ...
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2answers
305 views

Feynman diagrams in three dimensions

Is there such a thing as an extension of Feynman diagrams into three dimensions? Canonical Feynman diagrams use one space and one time dimension to visualize processes involving elementary particles ...
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1answer
414 views

What if the binding energy becomes larger than the rest mass?

Looking at the equation for binding energy and mass defect, $$ B = m_{\text{free}} - m_{\text{bound}} \\ \Rightarrow m_{\text{bound}} = m_{\text{free}} - B, $$ my question is the following. Suppose ...
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64 views

axial and vector resonances in composite higgs models

Is there a reason to believe that the axial resonances be heavier than the vector resonances in the composite higgs models? For instance, in http://arxiv.org/abs/0808.2071, to have zero tree level ...
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90 views

Do the proton PDFs change much with Q?

Specifically, the second moments, do they change much from say 100 to 1000 GeV? Why or why not?
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1answer
602 views

Why do some particles have a greater mass than others?

The property of mass that almost every particle possesses comes from the Higgs Field. It is this field, which permeates all of space, that particles interact with and hence obtain mass. But why do ...
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89 views

What are the implications if Supersting theory is discredited? [duplicate]

Please forgive my ignorance, I am not a student of physics in any capacity, therefor my understanding of string theory is extremely limited to say the least. Based on the recent lack of evidence in ...
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2answers
319 views

Spin of a particle and spin quantum number [duplicate]

what actually does the spin quantum number of a particle describe about? What it means when we say photon has spin 1, Higgs boson has spin 0, etc..?? What actually does that numerical value explain? I ...
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2answers
195 views

Why is it called “annihilation”?

The term "annihilate" literally means "turn into nothing". However, when a particle and antiparticle collide, they clearly do not turn into nothing; they simply transform into different particles. ...
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94 views

A question about how light hits a surface

my question is about how photons travel from a light source and hit an object. When you look at an object being hit by light the whole surface becomes brighter. What i'm trying to understand is why ...
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2answers
98 views

If a particle is a point of high intensity in a quantum field, how can it have charge?

The charge of a fundamental particle is a mysterious but obvious and well-known property of every non-neutral particle. I can understand how, if a particle is an object, or thing, for want of a ...
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1answer
206 views

In Klein-Gordon, why should infinite downwards photon cascades be possible?

Here is a simple point about the standard interpretation of the Klein-Gordon equation that for the life of me I've never been able to understand: Why would the existence of true negative energy ...
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3answers
207 views

Does a Photon leave trace in a silicon tracker?

I am having this image from ATLAS Detector. In gray you can see the ATLAS's Si Tracker.In Green you see the Electromagnetic Callorimeter. In red there is the Hadron Callorimeter and in Blue there ...
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199 views

Strong decays of baryons via quark-antiquark pairs

I have the doubly charmed $\Xi_{cc}^{++}$ consisting of ccu quarks. This is meant to decay via strong force, producing a light baryon (cud/uuc/udc etc...) and a quark-antiquark pair along with a ...
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1answer
328 views

What happens to string theory if spacetime is doomed?

What is expected to happen with string theory, if physics is reformulated according the lines hinted at by the twistor-uprising business discussed in this question and its answers for example and ...
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1answer
634 views

Why is the majorana particle a fermion?

My knowledge of quantum mechanics is rather limited, but what I always understood was that Bosons have integer spins and Fermions have half-integer spins. My question is very simple: the Majorana ...
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1answer
283 views

What dark matter can AMS currently find (or exclude)?

The rumor mill is running again, this time it's about the AMS experiment (Alpha Magnetic Spectrometer) that's going to make a major announcement soon. I suppose they are looking for peaks in gamma ...
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276 views

Effective operator in four-fermion interaction

In one book, I have got the following lines which I found myself unable to understand what is effective operator? The paragraph is given below: The weak interaction describes nuclear beta decay, ...
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2answers
142 views

What does it mean to gauge a group?

I'm starting to learn about gauge theories and Goldstone bosons. What does it mean for a group to be gauged?
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145 views

Trilinear gauge couplings: Spin

In non-abelian gauge theories self interaction of gauge fields is permitted, allowing coupling such as $WWZ$ (i.e. $Z$-boson decaying to $W^+W^-$) or ggg (i.e. gluon splitting into two new gluons). ...
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1answer
162 views

Understanding how mass spectroscopy works

Let me start by saying that I've posted this question here as well. I've posted it here because I think the questions I've asked involve the physics of molecules. So I’m trying to get a deeper ...
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2answers
249 views

Muon production in particle accelerator

PAMELA is a particle accelerator which have two concentric rings, protons are accelerated in the inside ring. At ISIS muons are produced when a 800 MeV proton beam collides with a graphite ...
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81 views

Pareto efficiency and Standard Model parameters

Pareto Efficiency is a well understood concept in economics, which basically is a condition where no one actor could be made better off without some one being made worse off. This condition allows ...
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6answers
2k views

What would happen if Large Hadron Collider would collide electrons?

After some reading about the Large Hadron Collider and it's very impressive instruments to detect and investigate the collision results, there is a remaining question. What would happen if the ...
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1answer
258 views

What is the importance of the Higgs-strahlung process in the Higgs search?

I would particularly like to know why this process is considered the main search mode for Tevatron but useless for search at LHC.