Questions tagged [heavy-ion]

Heavy ion collisions involve large atomic nuclei, and are run at modern particle accelerators like RHIC and the LHC.

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How is $s_{NN}$ defined?

$\sqrt{s_{NN}}$ is usually referred to as center-of-mass energy per nucleon-nucleon pair, although I have seen (probably erroneously) center-of-mass energy per nucleon. Taking that the first term is ...
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What’s the basic procedure to draw a QCD phase diagram?

Could someone recommend a book/resource where I can find a detailed way of sketching out a QCD temperature-chemical potential phase diagram using gap equations (eg. equations 35-37 or 39-40 as given ...
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How is the nucleus-nucleus CM energy per nucleon related the proton-proton CM energy in a circular accelerator?

If I understand it correctly, the center of mass energy per nucleon pair in heavy ion collisions is given by $$\sqrt{s_{NN}}=\sqrt{(p_a/A_a+p_b/A_b)^2},$$ where $a$ and $b$ label each colliding nuclei,...
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41 views

Invariance of Particle Distribution in Heavy Ion Colissions

I'm reading about about Heavy Ion collisions from the book by Csernai and i can't make sense of the proof that the particle distribution $f(x,p)$ is an invariant scalar. Before i quote the book: The ...
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Difference between particle rapidity and space-time rapidity

I have seen a lot of posts asking about the difference between the rapidity $y$ and the pseudorapidity $\eta$, and I understand it well enough (at least in the context of heavy-ion collisions). They'...
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How to convert GeV to AGeV? [duplicate]

The beam energy is sometimes in AGeV in collider papers. I'm stuck on how to convert AGeV to GeV.
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41 views

Quark gluon plasma at arbitrarily high temperature

Does the quark-gluon plasma become weakly coupled at infinite temperature (due to asymptotic freedom), or does it maintain some non-perturbative behavior?
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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 ...
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What is the “jet trigger” in heavy-ion collisions?

I saw the word "trigger" many times in papers. And never true understand it. It seems like to set an threshold when select jet? So I want to understand more clearly. Thanks for your help. Here is an ...
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590 views

What is the “smearing” in heavy-ion collisions?

I often saw the word "smearing" in some papers. I don't know what it means. This word doesn't have an appropriate interpretation which is related to physics in chinese. So I feel hard to get the key ...
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57 views

Why the reconstructed jet need to substract the “background”?

There is a trouble bother me a long time. I know it may be stupid question. But I really need your help. It's in the CMS paper: CMS Collaboration, CMS Physics Analysis Summary No. CMS-PAS-HIN-12-013,...
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Feynman type write up for particle physics observables?

In gist: Struggling particle physicist (on the verge of giving up) needs qualitative writeup/article of the various aspects of heavy-ion physics: Kinematics,transformation (Lab <-> Center of Mass)...
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223 views

Highest man-made temperature: why only 470 MeV?

In 2012, the ALICE experiment at CERN achieved a temperature of 5.5 trillion kelvin (5.5 × 1012 K). This was regarded as the highest man-made temperature. However, even this temperature seems ...
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52 views

Heavy Ion-collision and Big Bang

I have read heavy ion-collision can be used as a source of information about early universe but I don't know how these two are related. I would be glad if someone gives me a reference about this topic ...
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700 views

What is the difference between Monte Carlo Tracks and Reconstructed tracks in heavy ion collisions?

I am doing a simulation of heavy ion collision, so I want to know what is the meaning of Monte Carlo tracks, what is a reconstructed track, and also, what is the relation and difference between Monte ...
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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, ...
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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. ...
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83 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 ...
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180 views

Reference on stages of heavy ion collisions in particle physics

Is there any reference (book/review article etc.) where the physics of heavy ion collisions is overviewed? To be absolutely clear about things, I am looking for a introductory review which covers ...
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Hydro regime of strongly coupled field theory, low viscosity

I am trying to get an intuition for the following argument: In heavy ion collisions the central collision area can be described by almost ideal hydrodynamics at very early times after the impact. This ...
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209 views

Baryonic density in collision experiments

Does anyone know any way of estimating the net baryon density in collision experiments, e.g. in LHC, RHIC, or the upcoming ones at GSI-FAIR? I have comes across many hand-waving arguments, sample - ...
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Nucleon-nucleon collision density

Can someone help me derive expression for nucleon-nucleon collision density as a function of transverse plane coordinates (ultra-relativistic heavy ion collisions) using Wood-Saxon nuclear densities( $...
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What is “A” in AGeV?

AGeV means GeV per nucleon. But why A letter is used for such a short cut? Why not NGeV, for example?
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What's the potential of the LHC's heavy ion experiment?

RHIC has been the dominant player in heavy ion physics, producing tantalizing evidence in support of the entropy/viscocity formula from AdS/CFT. What's the potential of the LHC's Pb ion collsions? ...
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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 ...
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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 ...