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.
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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 ...
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Could we use particle colliders as fusion generators?
So I know the basic gist is that fusion power's main issue is sustaining the fusion. I also know that there are two methods. The Torus method and the laser method. The torus magnetically contains ...
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Can black holes be created on a miniature scale?
A black hole is so powerful to suck everything into itself. So is it possible that mini black holes can be created? If not then we could have actively disproved the rumors spread during LHC experiment....
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What is the current status of string theory (2013)?
I've seen a bunch of articles talking about how new findings from the LHC seem to disprove (super)string theory and/or supersymmetry, or at least force physicists to reformulate them and change ...
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Relativistic centripetal force
The thought randomly occurred to me that a circular particle accelerator would have to exert a lot of force in order to maintain the curvature of the trajectory. Many accelerators move particles at ...
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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 ...
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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?
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What would happen if you put your hand in front of the 7 TeV beam at LHC?
Some speculation here:
http://www.youtube.com/watch?v=_NMqPT6oKJ8
Is there a possibility it would pass 'undetected' through your hand, or is it certain death?
Can you conclude it to be vital, or ...
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Why doesn't the LHC accelerate electrons?
Electrons
have a much bigger charge density as the protons (and especially lead nuclei),
aren't compound particles as the protons (and especially lead nuclei)
are able to get a much bigger energy ...
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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 ...
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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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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 ...
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If the LHC-calculated mass of the Higgs is wrong, how long will it take to determine this with confidence? [closed]
After I watched "Particle Fever"--the movie about Large Hadron Collider (LHC) and the successful identification of the Higgs boson--I became a bit concerned with that team's handling of various ...
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What are the main algorithms the LHC particle detectors use to reconstruct decay pathways?
I am just starting to look into how we understand the data from particle collisions.
My question is, what are the algorithms or ways that these detectors interpret the data? Are there standard ...
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What does the data in various stages of analysis from a particle collision look like?
I've been following the news around the work they are doing at the LHC particle accelerator in CERN. I am wondering what the raw data that is used to visualize the collisions looks like. Maybe someone ...
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Why not using cosmic rays to study HEP, since they are way more energetic than LHC?
Cosmic rays energies can exceed $10^{8}$ TeV, way higher than the energy scale achieved in the LHC or that can be achieved in the near future.
cannot we just use them to study fundamental ...
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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 ...
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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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The Large Hadron Collider and Black Holes
Last week, I went to Switzerland and visited the LHC. I took a tour, and the guide told us that it is possible for black holes to appear in the LHC, but they will be so small, that they would ...
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Some very basic questions on the Higgs Boson
What exactly is a boson?
Is the Higgs boson the cause of gravity or a result of it? Does the collision of particles at the LHC create a gravity field or waves or somehow interact with the gravity ...
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Differences between reconstruction- and generation-level variables in HEP data
I am working on a CMS - related project where the ROOT trees contain both reconstruction-level and generation-level particle variables (like mass). However, I don't know the basic difference between ...
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If the LHC doesn't find the Higgs Boson, what would be the implications for the Standard Model?
What would be the implications to the Standard Model if the Higgs Boson hadn't been found with the LHC?
Also, if the Higgs Boson had not been found with the LHC, would it have been successfully ...
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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 ...
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Why is the LHC circular and 27km long?
The LHC in Geneva is a circular accelerator, 27 km long - why is it like that ?
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Which SUSY models are affected by the recent LHCb result?
The LHCb has recently published the observation of $B_s \rightarrow \mu^+ \mu^-$ with a branching ratio that agrees with the Standard Model (SM). There are many blog posts about it (See: Of Particular ...
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What does the latest $B_s^0\rightarrow \mu^+\mu^-$ results mean for SUSY?
A paper from the LHCb collaboration just came out last week, stating basically that the $B_s^0\rightarrow\mu^+\mu^-$ decay matches standard model predictions, and people are already shouting that SUSY ...
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How many $fb^{-1}$ for the most likely $5\sigma$ 115 Gev Higgs at the 7 Tev LHC?
How many $fb^{-1}$ of integrated luminosity at the 7 Tev LHC do physicists expect are needed, to make a $5\sigma$ discovery of the most likey 115 Gev Higgs, if it exists?
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Deciding what to collide at particle accelerator
Different particle accelerators use different types of collisions. For instance at the LHC they investigated p Pb collisions while its predecessor (LEP), used to collide electrons with proton and at ...
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What does the LHC do afterwards?
Astronomical telescopes are now mega projects and cost $1Bn and although they are pitched to solve the current interest of the day they are general purpose machines and with upgrades and new ...
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Higgs boson in LHC
Recently, the Higgs boson was discovered in the LHC. My question is:
How did they come to know that the particle created was actually the Higgs boson?
On the basis of which properties did they confirm ...
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Have we ruled out the Minimal Supersymmetric Standard Model (MSSM)?
This question is inspired by a Physics Stackexchange question posted 8 years ago (The future of supersymmetry). The question that I have is very similar to the question in the above link, except that ...
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random triggers
I understand that a small proportion of events at the LHC that would not trigger on any deterministic trigger are saved on what might be called a random trigger, so that, amongst other uses, proposed ...
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What would be the impact of slighty higher mass for the $W$ boson? [closed]
With the recent announcement from CDF
https://cerncourier.com/a/cdf-sets-w-mass-against-the-standard-model/
placing it at the mass at $$80,433.5 \pm 6.4\; \text{(stat)} \pm 6.9\; \text{(syst) MeV},$$ ...
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The future of supersymmetry [duplicate]
Considering the fault of any experimental evidence from LHC for supporting the supersymmetry idea until now, can we say that it is dead? Generally the people who are working on this subject say that ...
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Why is Higgs particle detected much later than top quark when it's lighter? [duplicate]
The Higgs boson is lighter than the top quark. But the top quark was discovered in the mid-1990s where the Higgs boson escaped detection for two more decades. So if the energy has already been ...
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What are the main differences between $p p$ and $p \bar p$ colliders
I know that it is somehow related to the parton distribution functions, allowing specific reactions with gluons instead of quarks and anti-quarks, but I would really appreciate more detailed answers !
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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 ...
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Particle colliders: why do they need an accelerator chain
Particle colliders like the LHC or the Tevatron use a complex accelerator chain to have particles at a given energy before being accelerated.
For example:
The CERN accelerator complex to inject in ...
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Unusual particle effects at CERN
In 2010 there were press reports that CERN had identified unusual properties in particle behavour in collisions. One link here.
Here is a partial quote:
"In some sense, it's like the particles talk ...
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Could a tetraquark $q \bar{q} q \bar{q}$ be colorless?
CERN just posted this article where it informs that it was found an hadron which cannot be classified within the traditional quark model. What other models are there to explain this result? Or is it ...
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What will be the goal of (V)LHC after receiving upgrades?
If I understood correctly, the LHC will be shut down at the end of 2012 to prepare for the full-power, 14 TeV collisions in 2014. I also remember reading about a proposed luminosity upgrade some time ...
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What is an inverse femto barn?
I came across the use of the unit barn and inverse barn while reading about the operation of LHC. What is an inverse femtobarn? What does it tell about the experiment being described?
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Will negatively charged strangelets be produced by the LHC?
Witten (and earlier, Bodner) hypothesized that strange matter (up, down, strange quarks) should be more stable than "regular" nuclear matter(The strange matter hypothesis). That is that the typical ...
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What is the temperature of an LHC Bunch?
From various places, I've found that an LHC bunch seems to be about 100mm long, 0.1mm wide, and contains about $10^{11}$ protons or anti-protons. The de Broglie wavelength is about $10^{-18}$ meters, ...
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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 ...
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Jet rapidity vs. Pseudorapidity
Thanks to this post
I got a better understanding of what makes (pseudo) rapidity an interesting and often-used concept.
Tangentially working with jet physics (the spray of hadrons kind of jet :), I am ...
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How can Kaluza-Klein particles be told apart from winding modes at the LHC?
I`ve already asked this in the comments below this article http://profmattstrassler.com/articles-and-posts/some-speculative-theoretical-ideas-for-the-lhc/extra-dimensions/how-to-look-for-signs-of-...
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What's the recent released 750GeV particle's spin?
I was told that it has recently been confirmed to be spin-2 particle, and potentially to be graviton. I'm pretty interested in how this has been examined.
Edit:
During the Moriond 2016 conference, ...
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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 ...
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