Physics motivation of HE-LHC

Particle physics accelerators in the current days focus on achieving better precision on various physics parameters defined by proved theories or looking for signs of new physics that would support new theories of our universe. The HE-LHC will move the window of energy that we can look through. It would double highest the energy ever achieved and improve statistics on the lower energies. Multiple theories of physics beyond the standard model (SM) of particle physics can be explored with the energy increase. First possible theory is the technicolor theory. Technicolor theory explains the electroweak gauge symmetry breaking through gauge interactions. These interactions are asymptotically free at very high energies, but unobservable at lower energies. It would solve the hierarchy problem of SM. One existing issue is that the Higgs boson is not predicted by the technicolor theory, but is also not excluded. The supersymmetry theory is another theory that offers a solution to the hierarchy problem. The HE-LHC will improve the search for the higher mass supersymmetric particles. Lastly, the ADD model (model with large extra dimensions (LED)) attempts to solve the hierarchy problem by explaining why is the gravitational force much weaker compared to the other fundamental forces, by taking into account extra dimensions. The LHC did not find candidates supporting this theory so far. The HE-LHC would improve the chances of such discovery (ADD should be detected between few TeV and 10^(16) TeV). It is hard to predict if HE-LHC will prove any of these theories true, but maybe after just a small energy increase, new physics will be discovered.

HE-LHC technology

The HE-LHC provides a step up from the current LHC technology, while not requiring construction of a new collider. It will allow to reach proton beam energy of 16.5 TeV. To double the energy of LHC while still using the same tunnel, HE-LHC will have to upgrade the LHC magnet technology to achieve 16 T magnetic field.

The main beam parameters are shown in the following table:

Parameters LHC HL-LHC HE-LHC FCC
CM energy (TeV) 14 14 33 100
Circumference (km) 27 27 27 100
Dipole field (T) 8.3 8.3 16 16
Peak Luminosity (x 10^(34) cm^(-2) s^(-1)) 2.06 5 25 5

HE-LHC has a five times larger target luminosity. Due to the overall size of the FCC, injection will become much longer process and therefore the rate of collisions will be smaller. The positive about building HE-LHC first is that it will be much cheaper and possibly new physics will be discovered in the 30 TeV energy region.

FCC will reach much higher beam energy, but it is a whole new project altogether.

Lattice design

The HE-LHC lattice is being prepared in the MADX software. The lattice is similar to LHC lattice as it uses the same tunnel. It will therefore have 8 straight sections and 8arc sections. Figure below shows the ring coordinates (with IP1 at (x,y) = (0,0)). The plot on the right shows the beta-x, beta-y and dispersion along the 27 km ring.

LHC / HE-LHC ring geometry Twiss parameters for HE-LHC
ss8.png ss2.png

The lattice files for HE-LHC are located at:

http://proj-lhc-optics-web.web.cern.ch/proj-lhc-optics-web/OpticsSourceAllVersions.link/HELHC/

it is a work in progress and new version are expected frequently.

Arc section

work on arc section - will be filled in shortly

Dispersion suppression

work on dispersion suppression section - will be filled in shortly

Topic attachments
I Attachment Action Size Date Who Comment
PNGpng ring.png manage 137.6 K 21 Mar 2018 - 11:30 HelenaPikhartova  
PNGpng ss2.png manage 274.7 K 21 Mar 2018 - 11:28 HelenaPikhartova  
PNGpng ss8.png manage 146.7 K 21 Mar 2018 - 11:34 HelenaPikhartova  

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Topic revision: r2 - 21 Mar 2018 - HelenaPikhartova

 
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