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.
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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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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 ...
15
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2answers
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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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2answers
656 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 ...
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2answers
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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 ...
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1answer
291 views
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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7answers
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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 ...
9
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2answers
548 views
ATLAS and CMS calorimeters
I was reading this interesting recent review on arxiv about particle identification:
Particle Identification
In figure 2, there is an interesting comparison between the CMS and ATLAS calorimeter ...
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710 views
Why is the LHC circular and 27km long?
The LHC in Geneva is a circular accelerator, 27 km long, why is it like that ?
8
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1answer
263 views
What if the 126 GeV particle found at LHC that LOOKS like the Higgs is actually not the Higgs Boson?
I am suspicious of the Higgs announcement. Press mania aside, the scientists seem careful to say only that "we've found something which looks like the Higgs Boson".
The difference between ...
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2answers
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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 !
...
7
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2answers
707 views
What if LHC finds SUSY?
Here and on many other forums and blogs people ask the question "What if LHC does not find SUSY?". I would like to ask the opposite. What if it finds it? What would the implications be? Is it going to ...
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3answers
283 views
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 ...
7
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3answers
282 views
How do they handle energy in magnets at LHC?
I'm guessing that when the LHC ramps up to 4000 GeV this means they are increasing the current in the superconducting magnets as RF fields accelerate the beams. Where does this current go when they ...
7
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2answers
477 views
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 ...
7
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2answers
806 views
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 ...
7
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1answer
717 views
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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1answer
314 views
Decay of SUSY particles
In discussion of LHC searches for SUSY particles, physicists seem to assume they will decay quickly to the lightest SUSY particle which then remains stable (at least within the time it takes to leave ...
6
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2answers
274 views
How relevant is LHC to quantum gravity?
Premise: the LHC is obviously mapping unseen territory in high energies, and therefore it's always possible to imagine far out results.
Excluding completely unexpected outcomes - is the LHC ...
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2answers
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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 ...
6
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2answers
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Hawking's alternative to Higgs Boson
I have seen in popular media, claims that Hawking does not believe the Higgs boson exists due to microscopic black holes and even made a bet against it. This is based on something published in ...
6
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1answer
299 views
LHC Big Bang Temperatures
It's been claimed that the LHC's 14 TeV energy produces temperatures comparable to that which occurred very soon after the Big Bang. The well-known $E=1.5kT$ formula from classical statistical ...
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1answer
237 views
Which collision energy at LHC is better for hunting 125 GeV Higgs, 7 TeV, 8 TeV or 14 TeV?
Increasing collision energy in hadron collders doesn't always improve the abiilty to hunt down the Higgs. I know that if the Higgs mass is just above LEP exclusion, then even 7 TeV is too high to be ...
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1answer
174 views
How much does a proton weigh when it is going around the LHC at CERN?
Considering that speed increases weight and the proton is going at almost the speed of light, I would like to know how much a speeding proton would weigh in the LHC.
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1answer
173 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. ...
5
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1answer
305 views
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 ...
5
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2answers
141 views
How should one combine the uncertainties from the ATLAS and CMS measurements?
First off, a naive theorist question - How are measurements divided between the different detectors at the LHC? I would imagine that for a short run time, say, the CMS detector is active and all the ...
5
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0answers
118 views
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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2answers
426 views
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 ...
4
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2answers
191 views
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 ...
4
votes
2answers
312 views
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 ...
4
votes
2answers
197 views
Assuming that extra dimensions will not be visible at LHC, what motivation will still remain to study them?
Many physicists believe that there is little possibility of observing extra dimensions at LHC so that some extra dimension models originally designed to solve hierarchy problem (ADD/Randall-Sundrum) ...
4
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2answers
54 views
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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1answer
112 views
Are old fashion photomultipliers used in LHC experiments?
Are any photomultipliers used in any of LHC detectors? Or are only semiconductor devices used?
If yes, then where?
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1answer
697 views
Advantages of high-energy heavy-ion collisions over proton-proton collisions?
Some high-energy experiments (RHIC, LHC) use ion-ion collisions instead of proton-proton collisions. Although the total center-of-mass energy is indeed higher than p-p collisions, it might happen that ...
4
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2answers
181 views
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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votes
6answers
240 views
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 ...
3
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1answer
260 views
What are the advantages of the ILC over the LHC?
USA Today has an article on Japan's interest as the site for the $10 billion future International Linear Collider. This accelerator will utilize electron/positron collisions (like CERN's former LEP ...
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3answers
266 views
How much would the LHC beam be attenuated by the atmosphere?
As I understand it, the completed Large Hadron Collider (LHC) will ultimately have a proton beam with $2,808$ bunches of $1.15 \times 10^{11}$ protons each at $7$ TeV, giving a total beam energy of ...
3
votes
2answers
118 views
Shouldn't LHC have used $p\bar{p}$ collisions, instead of $pp$ collisions, to study baryogenesis?
Baryogenesis is the physical process(es) that produced baryon antibaryon asymmetry in the early universe. That means, the laws that governed the bigbang was baryon-antibaryon symmetric.
On the other ...
3
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1answer
870 views
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 ?
3
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1answer
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Will Randall-Sundrum extra dimension scenario become defunct if not supported by LHC?
The Randall-Sundrum extra dimension scenario had been one of the most extensively studied class of theories. This offered a solution to the hierarchy problem. However, if this picture is not supported ...
3
votes
1answer
241 views
What is jet quenching and how far can the hydrodynamic analogy go?
I recently heard about jet quenching concerning data taken by the experiments at the LHC. Apparently it is related to the existence to the quark-gluon plasma. As far as I understood this ...
3
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1answer
466 views
What's the Standard Model width of a 125 GeV Higgs?
There's a fairly broad mass spread in the new results out of Atlas and CMS. I'm curious how this fits with the expected SM width.
3
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1answer
584 views
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 ...
3
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1answer
41 views
Convolving Parton Distribution Functions
I have the cross-sections as a function of $\sqrt{s}$ for a process with a $u$-quark and $u$-antiquark in the initial state (eg.: $u \bar{u} \to e^- e^+$). I have a standard parton distribution ...
3
votes
1answer
112 views
Sources for new experimental limits on susy models?
I know the LHC people are publishing new limits every now and then, but as a non-expert in reading experimental papers (yet), I was wondering if there's a friendly website that collects and presents ...
3
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0answers
194 views
How to integrate over rapidity for Parton Luminosities in LHC?
I want to make a comparison of parton luminosities between Tevatron and LHC. According to Factorization theorem the cross section in hadron colliders, as long as the partonic cross section has $\hat ...
2
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2answers
186 views
What would happen to a person that was inside the Large Hadron Collider when it is turned on? [duplicate]
Possible Duplicate:
What would happen if you put your hand in front of the 7 TeV beam at LHC?
Not a terribly scientific question, but one that I'm sure many people have thought about :)
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2answers
175 views
Batting averages of the Large Hadron Collider
As I understand it, the Large Hadron Collider's function is to throw particles into each other while avoiding hitting the nucleus?
If quantum mechanics dictate the position of a particle can only ...
