Sharif Digital Repository

The Large Hadron Collidor (LHC) will increase its luminosity to more than 10e35 cm-2 s-1. The large amount of data rates will provide enough datasets needed to probe rare Higgs processes, study the scattering of longitudinally polarized W bosons and physics beyond the standard model(BSM). In the upgraded version of the LHC, called High Luminosity LHC (HL-LHC), the number of simultaneous interactions per bunch crossing, aka pile-up, increases to 140-200. The large number of pile increases the possibility of confusion in distinguishing vertexes of interest due to the contamination from non-interesting vertexes. One of the methods to mitigate the pile-up, complementary to the precision tracking... 

To investigate many interesting and rare physics processes at the Large Hadron Collider, we need much more data. The High Luminosity LHC (HL-LHC) is a foreseen upgrade for LHC to increase its luminosity and get ten times more data until the end of HL-LHC.Without any intervention, The CMS ECAL will face many challenges in HL-LHC. The end-caps must be fully replaced, and the electronic structure of the barrels will be modified. This thesis addresses the R&D studies of both sections.For the barrels, a test beam experiment has been performed on a prototype 5x5 matrix of legacy PbWO4 crystals with the new Very Front End (VFE) boards and the data has been analyzed.For endcaps, a 3x5 martix of...