Towards a muon collider

A muon collider would enable the big jump ahead in energy reach that is needed for a fruitful exploration of fundamental interactions. The challenges of producing muon collisions at high luminosity and 10 TeV centre of mass energy are being investigated by the recently-formed International Muon Collider Collaboration. This Review summarises the status and the recent advances on muon colliders design, physics and detector studies. The aim is to provide a global perspective of the field and to outline directions for future work

Towards a Muon Collider

A muon collider would enable the big jump ahead in energy reach that is needed for a fruitful exploration of fundamental interactions. The challenges of producing muon collisions at high luminosity and 10 TeV centre of mass energy are being investigated by the recently-formed International Muon Collider Collaboration. This Review summarises the status and the recent advances on muon colliders design, physics and detector studies. The aim is to provide a global perspective of the field and to outline directions for future work.Comment: 118 pages, 103 figure

Erratum: Towards a muon collider

The original online version of this article was revised: The additional reference [139] has been added. Tao Han’s ORICD ID has been incorrectly assigned to Chengcheng Han and Chengcheng Han’s ORCID ID to Tao Han. Yang Ma’s ORCID ID has been incorrectly assigned to Lianliang Ma, and Lianliang Ma’s ORCID ID to Yang Ma. The original article has been corrected

Towards a muon collider

A muon collider would enable the big jump ahead in energy reach that is needed for a fruitful exploration of fundamental interactions. The challenges of producing muon collisions at high luminosity and 10 TeV centre of mass energy are being investigated by the recently-formed International Muon Collider Collaboration. This Review summarises the status and the recent advances on muon colliders design, physics and detector studies. The aim is to provide a global perspective of the field and to outline directions for future work

The construction of the phase 1 upgrade of the CMS pixel detector

The innermost layers of the original CMS tracker were built out of pixel detectors arranged in three barrel layers and two forward disks in each endcap. The original CMS detector was designed for the nominal instantaneous LHC luminosity of $1\times10^{34}\,\text{cm}^{-2}\text{s}^{-1}$. Under the conditions expected in the coming years, which will see an increase of a factor two of the instantaneous luminosity, the CMS pixel detector would have seen a dynamic inefficiency caused by data losses due to buffer overflows. For this reason the CMS collaboration has installed a replacement pixel detector during the recent extended end of year shutdown. The phase-1 upgrade of the CMS pixel detector will operate at high efficiency at an instantaneous luminosity of $2\times10^{34}\,\text{cm}^{-2}\text{s}^{-1}$ with increased detector acceptance and additional redundancy for the tracking, while at the same time reducing the material budget. These goals are achieved using a new read-out chip and modified powering and read-out schemes, one additional tracking layer both in the barrel and in the disks, and new detector supports including a CO$_{2}$ based evaporative cooling system, that contribute to the reduction of the material in the tracking volume. This contribution will review the design and technological choices of the phase-1 detector

Search for third generation squarks at the LHC (status of light stop and sbottom searches)

We present results of searches of the ATLAS and CMS experiments for third generation squark production in the context of supersymmetry. In many scenarios of supersymmetry the superpartners of the bottom and top quark are the lightest squarks. These particles could therefore be the first sparticles observed at the LHC. The ATLAS and CMS experiments have a wide variety of searches sensitive to third generation squark production that have been conducted with 2011 data sets. Their results are interpreted in simplified models where limits on different production and decay channels of stop and sbottom quarks have been set

The phase-1 upgrade of the CMS pixel detector

The pixel detector of the CMS experiment will be upgraded during the extended end of year shutdown during winter 2016/2017. The upgraded detector will operate at full efficiency at an instantaneous luminosity of ${2\times10^{34}}$\,cm$^{{-2}}$s$^{{-1}}$ with increased detector acceptance and additional redundancy for the tracking, while at the same time reducing the material budget. The design and technological choices will be reviewed, and the status of the construction of the detector and the performance of its components as measured in system tests are discussed

Measurement of ttHttH production in the diphoton channel and observation of heavy triboson production with the CMS detector in pp collisions at s=13 TeV\sqrt s = 13\ \mathrm{TeV}

We present two recent CMS results based on the full dataset of LHC Run 2. Decays of the Higgs boson to photons have been used to investigate the ttH process. A significance of 6.6 s.d. is achieved in this single channel. The product of cross section and branching fraction is measured to be $1.56^{+0.34}_{-0.32}$ fb. The sample is used to investigate the CP structure the top Yukawa coupling, and a pure CP-odd structure is excluded at 3.2. s.d. . We also present the first observation of production of three massive vector bosons. Events with 3 - 6 isolated electrons or muons, or 2 same-sign leptons and 1 or 2 jets in the final state have been used to search for $WWW$, $WWZ$, $WZZ$, and $ZZZ$ production. The combined significance reaches 5.7 s.d., with evidence for the individual $WWW$ and $WWZ$ channels. The combined signal strength is measured to be $1.02^{+0.26}_{-0.23}$.</p

CMS Forward Pixel Upgrade Electronics and System Testing

This note discusses results of electronics and system testing of the CMS forward pixel (FPIX) detector upgrade for Phase 1. The FPIX detector is comprised of four stand-alone half cylinders, each of which contains frontend readout electronic boards, power regulators, cables and fibers in addition to the pixel modules. All of the components undergo rigorous testing and quality assurance before assembly into the half cylinders. Afterwards, we perform full system tests on the completely assembled half cylinders, including calibrations at final operating temperatures, characterization of the realistic readout chain, and system grounding and noise studies. The results from all these tests are discussed