Pair Definition and 379 Threads

I think its true that you cannot use a bubble chamber to identify the pair production of a neutron-antineutron pair, but how (maybe if) is that studied? Is that reaction common in a proton collider?

Homework Statement How much energy is required to produce the electron-positron pair in the filed of nucleus (Z=20) if electron is captured to the ground 1s state of the system. The Attempt at a Solution I can calculate the energy of the captured electron from E = - εZ2/(2n2) where...

Homework Statement two photons collide head-on and create an electron and an anti electron. The energy of photon 1 is given, but not for photon 2. Find the velocity β of the systems rest frame (where the total momentum is zero.) Homework Equations β=v/c γ=1/√1-β^2) β=pc/E The...

Homework Statement There are two noninteracting, spinless, distinguishable particles an isotropic oscillator potential. One particle is in the state |1\rangle =\frac{1}{\sqrt{2}}(|1,1,-1\rangle + |1,1,0\rangle ) and the other is in the state |2\rangle = \frac{1}{\sqrt{2}}(|1,1,0\rangle -...

A positron and an electron are simultaneously fired from paralle particle accelerators a distance d apart, with equal velocity v. One calculation says that each one will, being a moving charged particle, induce a magnetic field B=\frac{\mu_0 q v}{4\pi d^2} and since the other is moving in...

If we assume that the Twin Prime Conjecture is true (and thus there are infinite number of primes that are 2 apart), how reasonable is it to assume that there will be an infinite number of Twin Primes that are preceded by a prime that is at least 10 lower than the first of the Twin Primes? (I...

Hi, I was reading some novice stuff about quantum entanglement and I was wondering if entanglement occurs in either of these two scenarios: 1. electron and positron entangled as a result of being created by a photon passing over a heavy nucleus 2. two free electrons entangled with...

I am learing the particle physics bit of my physics course and don't understand how momentum is conserved when a photon produces an electron/positron pair. In the bubble chamber chamber picture here...

My friend said that two horses pull the Magdeburg hemispheres with same force is as same as a horse pulls the Magdeburg hemispheres which is tell on a tree(I may forget the details about the assumption) Why? Another Q. about action and reaction i don't know why the reading isn't 2Mg,but is...

Can anyone help me, I am some what unclear on the reason why "conventional" superconductors have cooper pairs only in the singlet state. Is it something to do with the expectation values given for the separate states calculated from their spatial and spin wave functions? For example does the...

Homework Statement See first figure attached. Homework Equations The Attempt at a Solution See 2nd figure attached for my work so far at attempting the design. The last figure is what my textbook gives as the small signal analysis of a BJT differential amplifier with emitter...

My understanding is that when a particle-antiparticle pair is created, they will have opposite spins and momenta. So the net momentum will be zero. But doesn't the momentum depend on the frame of reference? Say the particles both have mass m and velocities +v and -v. Then the net momentum is...

Hello, This may sound silly, don't be afraid to let me know just how silly though! I've read that predictions are made using the standard model. I do not know the details of this process. I understand pair production occurs randomly in a vacuum, but I wondered if there was an underlying...

Why is that in twisted pair cable, the tighter the twisting, the higher the supported transmission rate? Thankyou

I've gotten interested in this pair production stuff, and I'm wondering: Why is it that some nuclei can absorb more energy than the energy needed for pair production, while other nuclei result with the incoming energy creating pair production? Is it because heavier nuclei can distribute the...

During electron-positron pair production, does electron capture always happen? Gracias

Hi, Someone told me that a potential of 10^6 volts is not stable because it would cause spontaneous electron-positron creation from the vacuum. Is this true? I thought one could reach higher potentials than 1000000 volts.

Hello, In a previous discussion of Pair production I was shocked by what I heard and I have some questions from the general explanation of the subject. So you can make fermions out of bosons? You can make rest mass out of energy? Does this mean that not just relativistic mass, but...

I was reading about electron-positron annihilation and I got to the part where it says that this is a reversible process, meaning that an electron and a positron could be created from photons. About this reverse process the article says "In nuclear physics, this occurs when a high-energy photon...

My grasp of physics is limited, however, I am an engineer, thus I am asking for other's assistance in understanding how to delay the annihilation of a virtual particle pair. Most literature I've read, indicates a virtual particle pair is "real" if only briefly. QUESTION: How long is...

I have been trying to solve the inverse Fourier transform: \int_{-\infty}^{\infty}\left[e^{-j2\pi ft_0}e^{j\theta}\right]e^{j2\pi ft}df I know that the Fourier transform pair says e^{-j2\pi ft_0}e^{j\theta} \leftrightarrow \delta(t-t_0) but the extra phase term e^{j\theta} makes...

The ordered pair <-3,2> represents vector XY. Give possible coordinates for X and Y? Homework Equations The Attempt at a Solution I really have no clue how to even attempt this problem since I haven't ever been given such a problem. Could I get any help please?

Hey guys, I just found out about these darlington transistors, and I read that the purpose of these transistors are to "amplify WEAK signals". After taking a look at the circuit diagram for the darlington pairs, it seems to me that it is just 2 npn bjts with one of the bjt's emitter...

Although there is no experimental evidence or QG theory, it is not unreasonable that very strong gravitational fields or very high energy gravitons would cause pair production of real particles. In view of the spin-2 nature of gravity, what might these pairs be? One electron, one positron and...

Homework Statement I'm given this interaction Lagrangian: L_I (x) = -g \overline{\psi}(x) \psi (x) \phi (x) where g is the coupling constant, \psi is an electron and \phi is a neutral scalar field. I have to calculate the amplitude for process \psi + \psi \rightarrow e^- + e^+ that...

If in a given DNA molecule a C-G base pair is changed to a U-G base pair the following mutational change in the DNA will result a. C-G to G-C b. C-G to T-A c. C-G to A-T d. C-G to A-U Can someone elaborate on this for me?

Homework Statement This is a special relativity question: Two gamma rays of identical energies E collide with an angle \theta between their velocities. Show that positron-electron pair creation is impossible in the limiting case \theta=0. Find the minimum \theta value for p-e creation to...

Hello. I have understood the Kuratowski definition of the ordered pair and appreciate it's usefulness but have a nagging difficulty about it. Consider an ordered pair which is (a,a). according to Kuratowski definition it is defined as {{a},{a,a}} . Now consider an ordered triplet (a,a,a) it...

Hi, I'm building a pair of helmholtz coils to do a variety of magnetism-related experiments. I've borrowed an old Avo Douglas coil winder and plan to do a couple of thousand turns on two sections of 50mm or 60mm diameter pipe. Some nylon threaded rod will pass through the middle of each coil...

Consider a proton and antiproton collision. The goal is to produce a top quark and anti-top quark pair. If a top quark has a mass of 174 GeV/c2, how much energy is required in the center of mass frame to produce the combination? I'm somewhat utterly stumped. Obviously, the problem deals with...

Hello, Would it be possible for an electron and positron to form a cooper pair if an electron is brought into the neighborhood of the positron who is anchored in a penning trap (or in some other fashion)? If normal cooper pairs form by using the the attractive force of the lattice...

I was looking at a picture (attachment) in a physics website and the following doubt arose: I previously thought that the weight of the block (gravitational pull of the Earth on the block) caused a reaction force of the table, but now, from what I understand and, please correct me if I am...

Homework Statement http://nplq1.phyast.pitt.edu/res/csm/csmphyslib/type66_inductance/PairOfCoils.jpg Coil A is a large 400 turn circular coil of radius 91.0 cm. Circular coil B has 160 turns, a radius of 2.0 cm and is located L = 92.0 cm from coil A along the same axis. The planes of the two...

Homework Statement what is the minimal wavelength of electromagnetic radiation to pair-produce an electron-positron pair? Homework Equations ~ = wavelength hc/~ = 2MeC^2 + K The Attempt at a Solution hc/~ = 2MeC^2 = 2(9.11x10^-31)(3x10^8)^2 ~ = 8.24x10^-11m is tis correct?

I never understood this how do 2 like charges stay together, the electro is it like eddy currents or something

Homework Statement Two point charges of magnitude 4.79 nC and −1.11 nC are separated by 39.4 cm. The acceleration of gravity is 9.8 m/s^2 The Coulomb constant is 8.98755×10^9 N · m^2 /C^2. What is the potential energy of the pair of charges? Answer in units of V. Homework Equations...

hi, am i right in saying that for gamma rays of energies above 10MeV, the main interaction mechanism is pair production? and this is independent on energy? (or is it compton scattering for example?) thanks

Has anyone ever done an experiment with an entangled pair (say a pair of photons of opposite spin) where both are measured at the same time (or at least a time less than the separation, d, of the two particles divided by the speed of light, d/c)? Less than d/c and more than d/c seem to be...

Please teach me this: Can a real photon be destroyed to create a pair of massive particle-antiparticle?.It seem that if it can be,the conservation of energy-momentum is violalated? Thank you very much in advanced.

1. Problem Statement What is the wavelength of each of the two photons produced when a particle pair of a positron and electron accelerated at 25GeV collide? Can the net result of this annihilation be only ONE single photon? Why or why Not? Homework Equations Etotal(initial) =...

Homework Statement Comment on the electric field lines of a pair of finite parallel plates (a) between the plates and (b) near the edges of the plates. Homework Equations The Attempt at a Solution

When an electron in a semiconductor is excited to a higher state, an electron hole pair is created. How does this not violate charge conservation, a charge of +e turns into a net charge of 0? Thanks for the help

I'd like some informed opinion on the following scenario, which in a certain article forms the basis of a controversial claim. Suppose an entangled spin anti-correlated pair of particles are generated by some process. Particle A flies off along the +z direction, particle B along the -z...

Isn't it that in entangled electron pair, it's random which side will have up and down spin... the two sides should produce opposite spin but the order is random.. however I'm confused by the following statements: "Recall that when you measure an electron's spin in one direction you...

"A high-energy photon creates a pi+ pi- pair." ? Homework Statement "A high-energy photon creates a pi+ pi- pair. What is the minimal frequency of the photon?" (+ other side questions) Homework Equations E = hf E = mc² The Attempt at a Solution Well superficially it looks very easy...

Homework Statement "Prove that pair production is not possible in the absence of matter." Homework Equations / The Attempt at a Solution First of all, I'll assume a photon is considered matter, cause two photons can create a pair. Second: I thought pairs pop into and out of existence all the...

Hey all, Just like to prefix this question with the statement that I am a computer scientist with a strong interest and passion for physics, so please forgive me if this question is a tad naive. With that out of the way, I have a general question about this image: It's from "The Little...

Homework Statement Hi Its just me again! I kindly need help on this question. Its as follows: The tracks of a positron and an electron created by pair production in a magnetic field curve in opposite directions. a) Why do they curve in opposite directions b)Both particles spiral...

What does "to be opaque to pair production" mean? (I'm talking about fireball). I know what a pair production is but I can't get the crucial point: does it mean the photons don't collide? If it is so that means an opaque-to-p.p.- source have a greater luminosity (emits more photons) than a non...

Homework Statement Show that, if (x1, x2) is defined to be {{x1. {x1, y2}}, then (x1, x2) = (y1, y2) iff x1 = x2 and y1 = y2. This is from Willard's General Topology, problem 1C. I think Willard is trying to develop the set theoretic definition of the ordered pair, but this doesn't seem...