# What is Particle collision: Definition and 53 Discussions

In particle physics, an event refers to the results just after a fundamental interaction took place between subatomic particles, occurring in a very short time span, at a well-localized region of space. Because of the uncertainty principle, an event in particle physics does not have quite the same meaning as it does in the theory of relativity, in which an "event" is a point in spacetime which can be known exactly, i.e. a spacetime coordinate.

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1. ### B What is the Volume of the Plasma Inside the LHC During Particle Collisions?

Could someone provide an ainformation what is the temperature inside the Large Hadron Collider (or similar systems) where the colision of particles happens? THANK YOU!!!!

4. ### I What would a hypothetical quark-quark collision yield?

As seen in the summary, my question is purely hypothetical and I understand that it would most likely be impossible to happen (or I just haven't read enough). The concept that quarks and leptons are the fundamental particles of the universe has existed for a while now - therefore we know that...
5. ### Speed and rest energy of a particle collision

I honestly have no clue where to start, any help would be great.
6. ### Point sized particle collision and no transfer of energy

Two identical point-sized particles with the same Y-coordinate were traveling along the X and Z axes respectively. Given that gravity is acting parallel to the Y-axis, will the particles when they eventually collide, continue traveling along the same linear path due to work done by either being 0?
7. ### Find the photon energy in the center of mass frame and vice versa

I tried to use the Lorentz transformation: ##E^{*}_{\gamma }=\gamma _{cm}E_{\gamma }-\beta _{cm}\gamma _{cm}p_{\gamma }## We have a photon, so it becomes: ##E^{*}_{\gamma }=\gamma _{cm}E_{\gamma }(\beta _{cm}-1)## Unfortunately, the solutions say that the correct way is to use the inverse...
8. ### Kinetic theory of gases and velocity correlations

I have been reading up on the kinetic theory of gases, and I'm unsure whether I have correctly understood why particle velocities become correlated after colliding. Is it because during the collision they exchange momentum and thus their velocities (and hence trajectories) are altered in a...
9. ### Velocity correlations and molecular chaos

I’ve been reading up about Boltzmann transport equations, and the concept of molecular chaos has come up, in which one assumes the velocities of particles are assumed to be uncorrelated. I’m a bit confused about the concept though. In what sense do the velocities become correlated in the first...
10. ### Center of Mass to lab-frame

Homework Statement a) [Solved] What is the threshold energy in the center of mass for production of an antiproton in a proton-proton collision? Make sure quantum numbers are conserved. (This one was easy and I manage to solve it) b) In a fixed target experiment calculate the proton beam energy...
11. ### I Measurement of a particle's position using photons

I've read that a particle's position can be measured by firing a photon at it, but how does one actually determine the position of the particle by doing this? What is the maths behind it (is it calculated from momentum conservation)? Furthermore, I've read that increasing the energy of the...
12. ### Physics of a Particle Collision

I have two point masses, m0 and mp, colliding (with no radii) in an Elastic Collision (no mass loss). One has initial velocity, V0i. The other has initial velocity, Vpi. How do I calculate the initial forces, Foi and Fpi then formulate the final forces, F0f and Fpf yielding the final...
13. C

### Calculate the particle energy in a collision

Homework Statement The particle J/Ψ can be produced in both proton-proton collisions and electron-positron collisions. a) Consider a proton beam incident upon a ﬁxed hydrogen target. Calculate the energy of the proton beam in the reaction p1 + p2 → p + p + J/Ψ b) Consider two counter...
14. ### I How to understand the derivation for this process in QFT?

I'm reading the book "Quantum Field Theory and the Standard Model" by Matthew Schwartz and I'm finding it quite hard to understand one derivation he does. It is actually short - two pages - so I find it instructive to post the pages here: The point is that the author is doing this derivation...
15. ### I Can Antiparticles Collide with Each Other and Create Energy?

Now it is common knowledge that antiparticles destroy particles on collision, and release the same amount of energy as if the masses of the two particles were combined and plugged into E=mc^2. But what about an antiparticle colliding with another antiparticle? Would they have the same effect on...
16. ### B Envisioning particle collision.

I constantly hear the term 'bits flying off' in a particle collision'. Isn't this somewhat misleading? Wouldn't it be more accurate to say that, in a collision, a 'fountain' of new particles are created and that our main aim is to use the energy resulting from the collision to create new...
17. ### EPE and particle collision (grade 12)

Homework Statement An alpha particle moving at 3.0 x 106 m/s [east] (m2 = 6.64 x 10-27 kg and q2 = +3.2 x 10-19 C) is headed directly towards a proton moving at 5.0 x 106 m/s [west] (m1 = 1.67 x 10-27 kg, q1 = 1.6 x 10-19 C). Find the distance of closest approach, assuming that they start from...
18. ### Entangled particle collision

I'm sure this idea has been considered since the invention of the particle accelerator. What would happen to an entangled particle if it's pair was collided in an accelerator? My guess is simply an end to entanglement but I'm too curious not to ask.
19. ### Special Relativity -- Elastic Particle Collision Algebra

Homework Statement Consider the following head-on elastic collision. Particle 1 has rest mass 2mo, and particle 2 has rest mass mo. Before the collision, particle 1 movies toward particle 2, which is initially at rest, with speed u (= 0.600c ). After the collision each particle moves in the...
20. ### Particle Collision: Max Deflection of 2kg Part

A particle of mass 2kg moving with speed 6m/s collides ellastically with another particle of mass 4kg traveling in same direction with a speed of 2m/s. Find max deflection of 2kg particle?
21. ### Particle collision problem (accelerator experiment)

Homework Statement An accelerator experiment collides a beam of electrons head-on with a beam of positrons. The particles in each beam have energy Ee as measured in the lab frame. Suppose one electron-positron pair collide to form a photon and neutral pion particle: e- = e+ ---> γ + π0...
22. ### Particle collision and deflection angle

Homework Statement Particle A of mass m has initial velocity v0. After colliding with particle B of mass 2m initially at rest, the particles follow the paths shown in the sketch (see attachment). Find ##\theta## Homework Equations collisions The Attempt at a Solution The momentum before and...
23. ### Two particle collision - One in excited state

Homework Statement (a)Find energy of photon emitted (b)Show that relative velocities after de-excitation are reversed (c)Find an expression for CM frame energy and find momentum of either particle in CM frame (d)Consider now, for a nuclear process and describe the initial and final conditions...
24. ### The use of cross section in a particle collision exercise.

1. Situation: I have no specific exercise in mind but just the general form. ''A beam of protons is colliding with a plate of a given particle density ##\rho## and thickness ##l##. The cross section is ##\sigma##. What should the thickness of the plate be such that the intensity of the outgoing...
25. ### Maximum rest mass in particle collision

Homework Statement Suppose that a certain accelerator can give protons a kinetic energy of 200 GeV. The rest mass of a proton is 0.938 Gev/c^2. Calculate the largest possible rest mass M0 of a particle that could be produced by the impact of one of the high-energy protons on a stationary...
26. ### Relativity and particle collision.

I have a question; If two particles (let's say protons) collide at high speed, they can produce heavy particles, like the Higgs. My understanding is that the high velocities make the particles more massive, allowing them to produce higher mass particles (relativity). So... If I fly past...
27. ### Particle Collision: What is Involved?

Dear members, please help me to understand clearly what we are talking about when the topic is the collision, scattering or absorption event of two particles. It is clear that there is a "qiuck" interaction between them. Also I know that we can consider the cross section For example let's...
28. ### Particle collision at an angle

Homework Statement A particle of mass m traveling at a velocity u makes a perfect elastic collision with a stationary particle. After the collision both particles are observed to be traveling in directions making angles of 30 degrees to the original path of the first particle. a) Use the...
29. ### Validating the kinetic energy for the two particle collision problem

Homework Statement The following is a summaration of a piece of text in my textbook: The setting is two particles moving in one dimension, under mutual forces, so that the equations of motion are (1): m_1 a_1=F and m_2 a_2=-F (a stands for acceleration) F is only a function of...
30. ### Year 12 Cambridge Physics: Classical Mechanics v Light Particle Collision

Question: A stream of particles, each of mass m and having kinetic energy E, is collimated into a parallel beam of cross-sectional area A. The particles are incident normally on a smooth plane surface at rate n and they rebound elastically. Derive an expression for the pressure on the surface...
31. ### Momentum conservation - particle collision

Homework Statement http://s359.photobucket.com/albums/oo40/jsmith613/?action=view&current=MomentumConservation.png Homework Equations The Attempt at a Solution Working out how momentum is consered in this situation,... I know that the mass of an alpha particle is 4*mass of...
32. ### Vector diagram - particle collision

Homework Statement see attached image Homework Equations The Attempt at a Solution So I know as it is a VECTOR diagram it must either be B or C So I checked that 1, 2, 3, 4 all pointed in the correct directions and they do in both diagrams. I chose B (but at random) and the...
33. ### Understanding the Total Energy After Particle Collision

Homework Statement In a particle accelerator a proton and an antiproton, traveling at the same speed, undergo a head on collision and produce subatomic particles. The total kinetic energy of the two particles just before the collision is 3.2 x 10^{}-10 J. State why the total energy after...
34. ### Determine the Energy of Electromagnetic Radiation After Particle Collision

Homework Statement The positron and the electron each have a rest mass of 9.11 x 10-31 kg. In a certain experiment, an electron and a positron collide and vanish, leaving only electromagnetic radiation after the interaction. Each particle is moving at a speed of 0.20c relative to the laboratory...
35. ### Available energy in particle collision derivation

Hello, I am trying to derive the formula given in by . I understand we need to move it to the center of momentum frame to solve. Using the relativistic energy equations. I find that : E = E1 + E2 E1 = sqrt((Mc)2+(pc)2) E2 = sqrt((mc)2+(pc)2) where both have equal magnitudes momentum p since...
36. ### Particle Collision, conservation of momentum

Homework Statement Consider the reaction pion(+) + neutron --> Kaon(+) + lambda particle(0). The rest masses of the particles are m(pion) = 140MeV,m(n) = 940MeV, m(K) = 494MeV, and m(lambda) = 1115MeV. What is the threshold kinetic energy of the pion particle to create a Kaon at an angle of...
37. ### Solve 2-Particle Elastic Collision: Mass m & Final Velocity -v/5

Hey, just doing some homework, and can't figure this one out Homework Statement Two particles go through an elastic collision. One particle has mass, m, and is initially at rest, while the other particle has initial velocity, v, and final velocity, -v/5. What is the mass of the second particle...
38. ### Exploring the Effects of 2GeV Particle Collisions on Fusion Reactions

Ive heard that fusion occurs at less than 1GeV(lets say that of proton-proton) but what if those same proton-proton collision occur at 2GeV? what will be the result?
39. ### Particle Collision: Example & Kinetic Energy

Hello, Is there an example in nature of two particles with only an attractive force between them directly colliding? If so, where does the kinetic energy go? Sam
40. ### Special relativity: particle collision

SOLVED: Special relativity: particle physics Tomorrow is the exam! My fourth SR question. Homework Statement There is a \beta breakdown(?) of a neturon, resulting in n \rightarrow p + e^{-} + \nu^{-}_{e} I have to find the maximum speed of the electron, the decomposing neutron is...
41. ### Where can I get some animated carton of particle collision?

Hi,guys. Where can I get some animated carton of particle collision.? It is better a gif file and I want insert it into a ppt file. There are some animations in LHC homepage, but they are too large.
42. ### Center of momentum for particle collision

Homework Statement Consider a collision in which a stationary particle with mass M is bombarded by a particle with mass m, speed v0, and total energy (including rest energy) Em. PART A: Use the Lorentz transformation to write the velocities vm and vM of particles m and M in terms of the speed...
43. ### Solving for Kcm in Particle Collision Problem

Homework Statement A particle with mass 'm' and kinetic energy 'K' collides with a stationary particle of mass M. Then it says to find the total kinetic energy in the center of mass system 'Kcm'. The answer is: K_{cm} = \frac{M}{M + m}K Homework Equations conservation of momentum...
44. ### Solving Particle Collision: Find Mass Ratio from Total Angle

So there is a particle with m1 that hits a particle m2 at rest, they bounce off at angles theta1 and theta2 from the horizontal. The original problem proposes that you can find the mass of the second particle from knowing the first particle, and the angles that they both make from the horizontal...
45. ### Solving for Angle, Momentum & Energy of Particle Collision

http://img530.imageshack.us/img530/7629/pnxl1.gif A particle p traveling with a speed of vpi = 3 m/s hits and scatters elastically from another particle N, initially at rest. Particle p is deflected through 90°, leaving with a speed of vpf = 2.7 m/s, and a mass mp = 2 kg. a) What angle...
46. ### Particle Collision: 3.00kg & 4.00kg Particles

Particle Collision Two A collision occurs between a 3.00 kg particle traveling with velocity v = (-4.00 m/s) i + (-5.00 m/s) j and a 4.00 kg particle traveling with velocity v = (5.60 m/s) i + (-1.80 m/s) j. The collision connects the two particles. What then is their velocity in each of the...
47. ### Particle Collision: Calculate Photon Wavelength

Homework Statement The results of particle collisions are observed using particle detectors. Sometimes the products of these collisions are themselves unstable and decay to give further particles; the products of decay can be photons. In one collision, a stationary \pi^\circ meson is produced...
48. ### How Many Collisions Occur in a Particle Collision Problem on the Unit Interval?

Homework Statement Suppose that five particles are traveling back and forth on the unit interval [0,1]. Initially, all five particles move to the right with the same speed. (The initial placement of the particles does not matter as long as they are not at the endpoints.) When a particle...
49. ### Particle Collision: Cars Collide at Intersection - Magnitude & Direction

A 1100 kg car traveling north (+j) at 70 km/h collides at an intersection with a 2000 kg car traveling west (-i) at 48 km/h. The two cars stick together. Find the magnitude and direction of the velocity of the wreckage just after the collision I did pythag. thereom and got 84.9, but it wrong??
50. ### Conservation of 4-Momentum in a 2 Particle Collision

Homework Statement Two particles, A and B, have the same rest mass, m. Suppose that, in O, A has 3-velocity (V,0,0) and B is at rest. The particles collide elastically at the origin and after the collision A has 3-velocity (a \cos(\theta), a \sin(\theta),0) while B has 3-velocity (b \cos(\phi)...