Tagged Questions
3
votes
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 ...
4
votes
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?
0
votes
0answers
79 views
What are the implications if Supersting theory is discredited? [duplicate]
Please forgive my ignorance, I am not a student of physics in any capacity, therefor my understanding of string theory is extremely limited to say the least. Based on the recent lack of evidence in ...
15
votes
6answers
1k views
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 ...
10
votes
2answers
127 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 ...
4
votes
2answers
195 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) ...
3
votes
1answer
117 views
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 ...
10
votes
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 ...
1
vote
1answer
186 views
Missing transverse energy, exact definition
This might seem basic, but it is a bit confusing. You hear about missing transverse energy a lot in SUSY searches due to the LSP which cannot be detected.
Let's say I have the 4-vector for the LSP. ...
3
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 ...
1
vote
0answers
196 views
What is the relationship between Luminosity, Intensity, and Flux?
I am always confused by the terminology:
In high energy particle scattering, and in particular, in the context of collider physics, what is the relationship between luminosity, intensity and flux? ...
2
votes
1answer
67 views
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 ...
0
votes
1answer
131 views
From where this number of 14 Tev has arised for proton-proton head on collision in LHC?
I am interested in finding out, why are collisions at 14TeV done in the LHC, instead of some other energy?
2
votes
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 ...
4
votes
2answers
425 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 ...
0
votes
1answer
188 views
What is the total kinetic energy per second of the particles accelerated by the LHC
Related: how many protons per second can the LHC accelerate?
3
votes
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
votes
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 ...
5
votes
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. ...
2
votes
2answers
305 views
If LHC is the most powerful microscope in the world, what does it magnify?
Some experts (and non experts) have called LHC the most powerful microscope in the world. I am wondering, what does the LHC magnify? Or is calling it a microscope just wrong and misleading?
7
votes
2answers
476 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 ...
15
votes
2answers
655 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 ...
7
votes
2answers
192 views
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
votes
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 ...
7
votes
2answers
706 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 ...
1
vote
1answer
227 views
With estimates of mass constraints on magnetic monopoles, how likely is one to be found by the LHC(MoEDAL)?
Fermilab seems to have ruled out monopoles with mass less than 850 GeV, but I have seen some estimates of the mass thought to be in the order of up to $10^{18}$ GeV, which, of course, would make them ...
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 ...
9
votes
2answers
547 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 ...
9
votes
7answers
1k views
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 ...
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 ...
4
votes
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 ...
2
votes
3answers
453 views
What does it mean a temperature of billions of degrees?
I read a few days ago that in the LHC temperatures of billions of degrees were achieved. I'm curious to know what does it really mean such a temperature? The concept of temperature is easy to grasp ...
