A message from our CEO about the future of Stack Overflow and Stack Exchange. Read now.

Questions tagged [large-hadron-collider]

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 with a centre of mass energy of up to 14 TeV. It contains the important detectors ALICE, ATLAS, CMS and LHCb.

Filter by
Sorted by
Tagged with
1
vote
2answers
35 views

Does deep inelastic scattering produce photon?

I know that DIS produces hadron jets, which are formed from the intense energy of the interaction. But I wonder, are photons also produced? And if so, what are the processes that create these photons?
41
votes
3answers
6k 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 ...
0
votes
0answers
34 views

Hadronic decay experimental result

I am looking for experimental results of hadronic decays cross section of the two following decays: $\Delta^{+} \rightarrow p +\pi^0 $ and $\Sigma^{*0}\rightarrow p + K^{-}$ I have already computed ...
6
votes
2answers
991 views

What are the advantages of an electron-electron collider vs. An elec./positron one? Has one ever been built?

The current LHC is a proton-proton collider (instead of proton-antiproton) for reasons I have read about elsewhere. Why has there never been an electron-electron collider? Also, I am reading now ...
6
votes
2answers
673 views

How detectors in particle colliders can differentiate neutrons from antineutrons?

Their mass is the same. None of them interacts with EM fields. And their decay (around 1000s) is far too slow to see their decay products yet in the detector. How is it then possible to differentiate ...
2
votes
1answer
61 views

Layman's questions about Supersymmetry

Please help me with two very silly questions. Assuming supersymmetry is correct, why don't we observe the superpartners of the Standard Model particles at ordinary energies? Why do we have to search ...
5
votes
2answers
469 views

Inelastic nucleon-nucleon cross section at LHC energies

I am trying to reproduce the number of participants $N_{part}$ in Pb-Pb Collisions at LHC using a Glauber Monte Carlo simulation, specifically aiming to reproduce the values given in Phys. Rev. Lett. ...
0
votes
1answer
139 views

Proton Proton Collisions Cross Section Plot by Stirling

I am struggling to understand some details of the cross section plot by Stirling that is very often shown when talking about LHC physics. See e.g. here: http://www.hep.ph.ic.ac.uk/~wstirlin/plots/...
3
votes
3answers
1k views

Nuclear fusion using electromagnetic fields

I was just thinking about how deuterium and tritium are charged particles and so I couldn't help but wonder why we don't use the same process used in the LHC(electromagnetic fields to accelerate ...
2
votes
1answer
65 views

If a particle and its antiparticle annihilate upon contact, how do they form bound states?

I am reading about some old discoveries in particle physics and early collider experiments from Perkin's Introduction to High Energy Physics. However, I didn't get the answers to all my questions. If ...
10
votes
1answer
180 views

How does the “Look Else Where Effect” affect the chances of detecting a false diphoton excess at the LHC?

Back in December 2015, there was found a 750 GeV diphoton excess in both CMS and ATLAS at the same location with a significance well above $3\sigma$; a 0.13% chance of being false. However, there ...
1
vote
1answer
45 views

How LHC sensors work? [closed]

newbie here. I am here because after working with Raspberry Pi sensors and Analog to Digital converters, and computer processors, I wondered how exactly do sensors in large scale physics experiments ...
0
votes
1answer
109 views

2019 Higgs Boson Mass?

Wiki, based on the 2018 Particle Data Group, gives the Higgs boson mass as $125.18 \pm 0.16$ GeV$/c^2$. OK. However, 2017 ATLAS gives a combined value of $124.98 \pm 0.28$ GeV$/c^2$. So what is ...
2
votes
1answer
195 views

How do they draw collision pictures in Atlas?

Is the picture below a simulation? How to they draw these pictures? The picture is from here.
0
votes
1answer
48 views

What is the point of particle accelerators with lower energies than the LHC?

Brazil's scientists are building a synchrotron, named Sirius. I'm wondering what the point of building this synchrotron is. From Sirius's Wikipedia page, it reaches an electron energy of 3 GeV. This ...
2
votes
1answer
32 views

How to know what production channel Higgs came from?

There are four main production channels for SM Higgs: ggF, VBF, Higgstrahlung and associated top. In multiple occasion I've seen experimental bounds referring to say $\sigma(gg \to H \to \tau^+\tau^-)...
0
votes
2answers
330 views

Cut-flow in experimental particle physics (offline analysis)

In experimental particle physics, when analyzing data from some experiment we require a baseline event selection by applying "cuts" on kinematic variables such as the pseudorapidity $\eta$, transverse ...
0
votes
0answers
38 views

Why there is accelerator chain at LHC?

Why can the LHC not accelerate protons to several TeV in one go? What is the limitation? My Answer: First reason is to minimize the cost of LHC accelerator construction by utilizing the previous ...
0
votes
0answers
27 views

Total cross section in hadron colliders with optical theorem?

In hadron colliders (like LHC) the total cross-section is calculated using the optical theorem. The origin of this is the scattering of two particles which is solved with the Schrödinger equation ...
0
votes
0answers
18 views

Hadronization in a collider

Say, in a collision, do the quarks need to first hadronize to pions? Or is there a probability that they can hadronize directly to heavier particles like the charm quarks.(quark-anti-quark pair) The ...
1
vote
2answers
103 views

Why is particle physics called high energy physics? [duplicate]

The highest energy accelerator till date is the LHC which operates at an energy scale of perhaps 10-100 TeV. In SI units this is about $\sim 10^{-6}-10^{-5}$ Joule which is several orders of magnitude ...
0
votes
2answers
69 views

Collider Luminosity basics

In a collider experiment, the Luminosity is defined as the proportionality factor between the interaction rate and the interaction cross section $dN/dt = L\times\sigma$, with units of $cm^{-2}s^{-1}$. ...
3
votes
1answer
103 views

No supersymmetric particles have been found in the LHC. Isn't this proof that Supersymmetry doesn't exist? [duplicate]

The LHC can reach energies from $7(TeV)$ to $13(TeV)$ (see here) and the question of which this is supposed a duplicate. Which I think it isn't, because in that question (which has been asked already ...
48
votes
4answers
9k views

What if the LHC doesn't see SUSY?

A question in four parts. What are the main problems which supersymmetry purports to solve? What would constitute lack of evidence for SUSY at the proposed LHC energy scales (e.g. certain predicted ...
1
vote
2answers
67 views

What superstring or brane phenomenology can be observed in LHC heavy ion collisions?

What superstring or brane phenomenology can be observed in heavy ion collisions at the LHC energy densities. Of course, I am aware that LHC experiments can constrain the conclusions from the ...
3
votes
1answer
159 views

Is anything expected to be found at CERN with 14 trillion electron volts that wasn't found at 13?

Based on this article the accelerator has smashed together approximately 16 million billion protons since 2015, when it reached its current energy of 13 trillion electron volts. Planned ...
0
votes
2answers
105 views

What is the definition of beam energy in particle physics?

For example, the proton beams in the LHC collider have 7 TeV energy. Does this mean that the individual protons in the beam have 7 TeV energy or that the energy of all the protons in the beam add up ...
3
votes
1answer
83 views

Current experimental evidence of lepton flavour violation other than neutrino oscillation

Is Lepton Flavour Violation (LFV) experimentally established in processes other than neutrino oscillation? This answer by Luboš Motl points out that Interestingly, CMS has detected a 2.5 sigma ...
1
vote
1answer
54 views

What happens with the energy released after a particles collision?

From the website of CERN: "Collisions in the LHC generate temperatures more than 100,000 times hotter than the centre of the Sun.". My question is, what happens to the energy released after the ...
64
votes
4answers
7k views

How do we know the LHC results are robust?

Nature article on reproducibility in science. According to that article, a (surprisingly) large number of experiments aren't reproducible, or at least there have been failed attempted reproductions. ...
3
votes
1answer
99 views

Cherenkov light and refractive index

LHCb’s Ring Imaging CHerenkov detector (RICH) is aimed at telling different charged particles apart by measuring their velocity, which, together with an independent measurement of their momentum, is ...
5
votes
2answers
483 views

What are “large hadrons”? Are there also “small hadrons”?

The BBC News article Cern plans even larger hadron collider for physics search says: The difficulty with Cern's proposals for a larger Large Hadron Collider is that no one knows what energies will ...
3
votes
3answers
340 views

Energy of the particles in the particle accelerator

Recently I came across something and I was surprised. I always thought that huge amount of energy is required to accelerate particles in the accelerator in the particle physics.But looks like no. The ...
0
votes
0answers
24 views

Effect of Lepton Flavor Universality (LFU) on Lepton Flavor Violation (LFV)

Does the search for Lepton Flavor Violation (LFV) get affected in any possible way when Lepton Flavor Universality (LFU) is used for background estimation? More specifically, because tau's show some ...
0
votes
0answers
17 views

Drell-Yan Process notes

As the title suggests, I am looking for notes on the Drell-Yan procedure. Specifically, I want to understand how the convolutions with the parton distribution functions appear and the general ...
18
votes
2answers
1k views

Correlation between outstanding hints in experimental particle physics

The 115 GeV ATLAS Higgs with enhanced diphoton decays has gone away but there are several other recent tantalizing hints relevant for particle physics, namely CoGeNT's 7-8 GeV dark matter particle ...
1
vote
1answer
80 views

Antiproton production threshold

Why is the antiproton threshold on cern 6* m_p and on uspas it is 7 * m_p?
15
votes
2answers
757 views

What is the 'bump' near $M_{\mu\mu}\approx 30\text{ GeV}$

In this (attached) Summer 2011 plot from CMS (twiki page), they have a plot of the dimuon invariant mass spectrum across 3 orders of magnitude in energy. There seems to be a 'bump' near $M_{\mu\mu}\...
0
votes
2answers
88 views

Big Data Handling at the LHC

My understanding is that much of the data that is is collected at the Large Hadron Collider is similar to that in the image below, and that a vast amount of the data contains little of specific and ...
4
votes
1answer
158 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. ...
1
vote
1answer
123 views

Can modern/future particle accelerators create a blackhole that “eats” the planet?

I dont think so myself, but this article: Earth could be crushed to the size of a soccer field... on Science Alert is being picked up by media. It seems to be a regurgitation of this article from UK's ...
1
vote
2answers
85 views

Could we use experimental evidence of micro black holes to prove the existence of additional spatial dimensions?

They are planning to create a new particle accelerator that can smash particles together at a much higher energy than the LHC. If in the process we observe the decay of a micro black hole, would that ...
0
votes
1answer
65 views

Don't matter-antimatter annihilate each other completely releasing energy as photon?

Matter and antimatter should annihilate each other completely releasing energy in the form of photon, however it is discovered that smashing electron and positron together can also spew out higgs ...
1
vote
1answer
14 views

Does superconducting magnet prevents energy loss when hadron is being accelerated?

I read up on how synchrotron works and electron will heats up by emitting photon when it is steering(accelerating) around a bend, so more bends more heat loss. By heat I mean energy not necessarily ...
0
votes
1answer
60 views

How to analyse the LHC signal for Higgs?

With increasing energy the collision decreases in the plot for signal in LHC. why is that? and at an energy 125GeV the no of events suddenly increases. How this proves that higgs has a mass of 125GeV?
1
vote
1answer
29 views

What would happen if antiprotons were studied under the conditions of particle deceleration that they are collected under? [closed]

I have not had a very clear understanding of how antiprotons are collected, but I do know that when they collide with matter they explode in a puff of energy. Or so I have been told. If the current ...
1
vote
0answers
31 views

Is it possible to replicate condition at planck time after big bang by smashing 2 protons really hard?

Because we need to achieve really really high temperature to mimick the condition just planck time after big bang, so suppose we can accelerate 2 protons at extremely close to speed of light and let ...
1
vote
0answers
52 views

How can a single particle hit many pixels in Large Hadron Collider?

In the Large Hadron Collider, the way particles are detected (specifically in ATLAS) is analogous to detecting photons using a photodiode(analogous is an exaggeration, but will suffice for the ...
1
vote
1answer
100 views

Can a rebranded super-symmetry be consistent with the null results at the LHC

To explain the null results on SUSY at the LHC, it continues to be assumed that the achievement of the energy threshold for the creation of the SUSY partners is beyond the capability of the ...
0
votes
3answers
72 views

How is antimatter stored in the large hadron collider?

we studied that antimatter can be stored in the large hadron collider. what i dont get is that the collider is used to collide particles and antiparticles together right? so how is antimatter stored ...