World's largest particle accelerator built by the CERN (European Organization for Nuclear Research) near the Franco-Swiss frontier near Geneva, Switzerland. It is designed to collide beams of protons of up to 7 TeV. It contains the important detectors ALICE, ATLAS, CMS and LHCb.

learn more… | top users | synonyms (1)

2
votes
0answers
51 views

Explanation of graphs from CERN [on hold]

I have a few questions about these kinds of graphs What is the name of this type of graph? What does the width of the peak mean? If the points are data points, how was the curve created/predicted? ...
1
vote
1answer
52 views

How do I calculate the differential cross section with respect to the transversal momentum?

First of all, sorry for my English, my first language is German. My problem is: I calculated the matrix element of the quark-gluon-Compton process (q+g -> gamma + q). With the kinematics of ...
27
votes
3answers
3k views

How can an electron fake a jet?

This is a question for experimentalists. I have seen in several ATLAS papers (see for example chapter 4 in arXiv:1602.09058, 6th paragraph), that after objects have been correctly identified, any jet ...
-3
votes
0answers
32 views

Is the LHC more dangerous if it works with more luminosity? [duplicate]

We've seen the restart of the LHC the last year, there were many rumors about the high-energy collisions at 13 Tev, there were some theories about black holes at 11 Tev or 9 Tev if there were other ...
6
votes
1answer
148 views

Why did it take so long to find the Higgs?

The $W$ and $Z$ boson took a long time to be discovered because they were so heavy; we couldn't produce them in a particle collider until the 80's. But the Higgs boson isn't that much heavier than the ...
3
votes
1answer
51 views

In the LHC, how is the proton separated from the electron in the hydrogen? [duplicate]

I know that we use protons in the LHC. So my question is, how is the proton separated from the electron in the hydrogen?
0
votes
0answers
36 views

Why do Higgs decays depend on the production method?

I'm reading about Higgs phenomenology and I have come across the following table. I don't see why gluon fusion to $b \bar{b}$ is considered to be "impossible" in this table. As far as I can tell, ...
1
vote
0answers
41 views

What experiments can we conduct using CERN's beamline? [closed]

I am participating in a competition organised by those brilliant people at CERN. Here’s where the trouble arises: -None of my school’s teachers are well-versed in particle physics -My country, ...
0
votes
0answers
17 views

Parent particles. Production modes of hyperon $\Lambda$

In the PDG are listed the decay modes of the known particles. I wonder if there exist lists with the production modes of particles. It is, lists with all the possible parent particles that decay into ...
0
votes
0answers
34 views

Proton-Proton collision [duplicate]

How are the people at CERN able to exactly collide protons head on? What about the HUP? Do they accelerate many particles and smash them so that at least some of them collide head on?
0
votes
0answers
13 views

What is the meaning of the minimum separation requirement?

In this work, BHsearch done by CMS, they reconstructed and identified objects using certain conditions. And finally, in Page 3, the last paragraph requires that the minimum separation between any two ...
1
vote
0answers
27 views

How does a Collider work? [closed]

How does a collider work, explained using various Physics theories (or if there is a main one) . How does the acceleration play a part in the individual sub-atomic kinetic levels. What happens when ...
2
votes
0answers
60 views

Effective collision energy at LHC

The proton is not a fundamental particle, so in high energy proton-proton collision we actually collide proton's sub-constituents: quark-quark and (mostly) gluon-gluon. LHC operates now at 13 TeV ...
35
votes
4answers
5k views

Why is 7 TeV considered as a big amount of energy?

Considering that $7$ TeV is more or less the same kinetic energy as a mosquito flying, why is it considered to be a great amount of energy at the LHC? I mean, a giant particle accelerator that can ...
3
votes
1answer
120 views

How the LHC bump can be a mere coincidence?

Speaking of http://www.nature.com/news/lhc-sees-hint-of-boson-heavier-than-higgs-1.19036. I understand that such a bump can be a statistical fluctuation. What troubles me is that the bump has been ...
0
votes
1answer
68 views

How are the protons for collisions in the LHC made?

I heard that the LHC smashes two protons together to research the universe. But how does it create the protons for collision? If we strip off the electrons won't there be neutrons along with protons? ...
0
votes
1answer
90 views

Could the Large Hadron Collider accelerate one kilogram of protons at once?

Is it possible to accelerate a very large number of protons in a particle accelerator as opposed to only a few as is regularly done? What's to keep someone from accidentally dumping too many particles ...
1
vote
2answers
83 views

Where all those particles come from - proton proton collision

I was reading an article about the "Higgs factory" China is planning to build and it got me thinking about what happens when two protons collide. I am an engineer so I have a good understanding of ...
0
votes
1answer
67 views

Head on collision of two black holes

LHC was built to collide two atomic particles to study contents within them. There are millions and billions of black holes present throughout galaxies. As collision between the galaxies is common in ...
3
votes
5answers
167 views

The use of electrons in synchrotrons

I'm researching synchrotrons for a class project, but I can't seem to find a decent answer to one of my questions. It appears that most synchrotrons use electrons as opposed to some other charged ...
3
votes
1answer
77 views

How are the two proton beams at the LHC accelerated in opposite directions?

At the Large Hadron Collider (LHC), how are the protons in the two beams accelerated in opposite directions?
2
votes
0answers
43 views

How much damage do high energy experiments impose on the LHC detection equipment?

I do appreciate that I am second guessing lots of experts who have already considered this aspect of high energy experimentation, but I have not seen a similar question, my apologies if I missed a ...
1
vote
3answers
141 views

New particles found using the LHC

After finding the Higgs boson in 2012, CERN. What did the CERN found recently using the large Hadron Collider?
1
vote
0answers
64 views

Does this phrase in “Knocking On Heaven's Door”, refer to gravitons?

This is an extract from Knocking On Heaven's Door, by Randall (2011) The suprising fact is that if you have a stable particle whose mass corresponds to the weak energy scale that the LHC will ...
1
vote
1answer
274 views

The (relativistic) mass of a proton in the LHC

What would be the (relativistic) mass of a proton, in grams, as it is traveling at the maximum possible speed in the LHC?
3
votes
1answer
53 views

Precise definition of Jet Energy Scale and Jet Energy Resolution

I've been struggling to get the precise meaning of these two quantities, is it correct to say that the first one is only related to Montecarlo simulations? I can't seem to find a pedagogical ...
1
vote
1answer
80 views

Collision symmetry and measuring the asymmetry in the Drell-Yan process

I saw a talk the other day about an asymmetry in the Drell-Yan process caused by CP-violation: Apparently one way this can be measured (ATLAS is doing this) is to collide protons and observe the ...
1
vote
1answer
50 views

How many pairs of nuclei collide in heavy ion collisions?

As each bunch of heavy ions consist of a large number of nuclei it does not seem unlikely that multiple binary ion collisions will occur as it does in p-p collisions. However, should this be the case, ...
0
votes
1answer
122 views

Objects colliding at relativistic speeds combined energy?

LHC is currently capable of accelerating a batch of atoms faster than $0.5 \, c$. What if we made a second LHC that intersects the original at, lets say the atlas chamber, but that runs in the ...
2
votes
1answer
63 views

Do we regularly measure and update our physical constants (By using the LHC)?

This question is motivated by sheer curiosity. I certainly do not expect that the free parameters we use in the standard model have changed in value since we started measuring them with a "modern" ...
13
votes
5answers
3k views

Earth still exists - does this fact tell us anything about LHC safety?

When LHC was about to be launched there were many fears that it would destroy the world. To counter them scientists tried to carefully examine all possibilities and concluded that there is nothing ...
4
votes
1answer
67 views

What energy will the LHC use for pA collisions in Run 2?

Part of the LHC's Run 2 (which just recently started) will be dedicated to proton-ion collisions, but I haven't been able to find any firm information about what energy those collisions will run at. ...
3
votes
1answer
53 views

Why in particle physics the background of resonance is a decaying exponential?

When in particle physics they plot the mass histogram we see a resonance on top of a decaying exponential background? Why is the background modeled to be that way? what is the physical explanation? ...
5
votes
1answer
92 views

What is meant by a preliminary run at the LHC?

I am a bit confused over the meaning of "Preliminary run" when referring to the LHC experiments CMS and ATLAS. For example in this summary, Figure 2 refers to both the CMS $19.7\ \mathrm{fb^{-1}}$ ...
3
votes
2answers
416 views

Why can't gravitons be created in traditional particle accelerators?

I've heard that it is incredibly difficult to detect a graviton, but I don't quite understand why. With all of the knowledge I have at the present time it seems like it should be possible to create a ...
0
votes
0answers
42 views

CMS magnetic field outside

The magnetic field at CMS is often given as 4 T. According to this picture the field outside the solenoid is just 2 T. Is this just because the field of a solenoid is not constant and decreases with ...
0
votes
0answers
32 views

What processes are involved in proton proton collision?

There is a lot of advanced materials at the internet but nowhere can I find brief introduction to the topic of proton-proton collisions in collider experiments (such as the large hadron collider). Can ...
1
vote
1answer
93 views

Decay channels of the Higgs Boson in Large Hadron Collider particle production

I attach a diagram of 4 of the (many) possible decay channels produced by the Higgs boson, and I have read that 57 % of the time, we find a bottom quark, antibottom quark pair resulting from this ...
6
votes
0answers
112 views

Large Hadron Collider 2015 upgrade, what may we discover?

I realise that the initial answer to my question that may come to mind is, "we don't know yet, obviously" But my question is hopefully not opinion based. For example, does this upgrade have a ...
2
votes
1answer
222 views

Signs of supersymmetry and thus dark matter at CERN

The Large Hadron Collider at CERN has just re-started after a two year pause and is now running at unprecedented levels of 6.5 TeV, with collisions that will release up to 13.5 TeV. With this increase ...
2
votes
1answer
58 views

How many different experimental configurations does the Large Hadron Collider have?

I understand that the LHC can collide protons with protons, heavy ions with heavy ions, or protons with heavy ions, giving three main configurations. But, I'm wondering: is that the only property that ...
2
votes
1answer
398 views

Is there a significant possibility of the LHC missing “exotic” particles or events?

In his popsci book, "Particle at the end of the universe", Sean Carroll says that the LHC, due to it's sheer information gathering capability, necessarily needs to completely discard most of the data ...
2
votes
1answer
151 views

With the LHC about to restart as max energy, are there absolutely no hints or tantalizing signs of Supersymmetry in previous data?

Over the last couple of years I've seen several articles talk about hints or bumps in the data that might point to Supersymmetry. An article in NewScientist from Summer 2012 discussed the discovery of ...
9
votes
2answers
793 views

How do tracking detectors in particle accelerators create the pretty pictures we see?

I have read several sources about tracking detectors used in particle accelerators like LHC, but still have not found a more detailed source that can still be understood by a layperson like myself. I ...
7
votes
3answers
1k views

Why don't protons just bounce off each other in the LHC?

Ok, this might sound like a silly question, but I was wondering, when particles (e.g. protons) are smashed together in the LHC, why do they break up into dozens of other particles, as opposed to just ...
5
votes
1answer
141 views

Why does gg fusion dominate over q qbar annihilation at the LHC?

The cross section of top quark pair production is dominated at the LHC by gluon-gluon fusion, whereas at Tevatron, quark-antiquark annihilation is more prevalent. Why is this? I know the fundamental ...
4
votes
0answers
52 views

Will the new LHC data falsify some theories? [closed]

There are plenty of extensions of the Standard Model, that all agree until the energy scales that have already been explored, but will differ at the new energy range of 14 TeV. This means the data ...
1
vote
3answers
583 views

Could the LHC be used for fusion experiments? [duplicate]

Just looking at the beam energy and peak power for the LHC, 360 MJ and petawatts, respectively, dumped in about 100 µs, would this be sufficient to do useful fusion experiments?
2
votes
2answers
79 views

Practical understanding of energies in LHC collisions

Is visible light emitted at the point of collision in the LHC? If so, how bright? How much water could be heated up by 10 degrees celsius (this is the energy from collision only, not the energy to ...
1
vote
2answers
145 views

Dark matter: Will Special Relativity hold?

Part 1: It’s been said that dark matter makes up about 26 % of the universe. The restart of LHC would be dealing with the existence of dark matter also. Consider a situation that the results are ...