This document summarises the current theoretical and experimental status of the di-Higgs boson production searches, and of the direct and indirect constraints on the Higgs boson self-coupling, with ...the wish to serve as a useful guide for the next years. The document discusses the theoretical status, including state-of-the-art predictions for di-Higgs cross sections, developments on the effective field theory approach, and studies on specific new physics scenarios that can show up in the di-Higgs final state. The status of di-Higgs searches and the direct and indirect constraints on the Higgs self-coupling at the LHC are presented, with an overview of the relevant experimental techniques, and covering all the variety of relevant signatures. Finally, the capabilities of future colliders in determining the Higgs self-coupling are addressed, comparing the projected precision that can be obtained in such facilities. The work has started as the proceedings of the Di-Higgs workshop at Colliders, held at Fermilab from the 4th to the 9th of September 2018, but it went beyond the topics discussed at that workshop and included further developments. FERMILAB-CONF-19-468-E-T, LHCHXSWG-2019-005
The CERN RD53 collaboration was founded to tackle the extraordinary challenges associated with the design of pixel readout chips for the innermost layers of particle trackers at future high energy ...physics experiments. Around 20 institutions are involved in the collaboration, which has the support of both ATLAS and CMS experiments. The goals of the collaboration include the comprehensive understanding of radiation effects in the 65 nm technology, the development of tools and methodology to efficiently design large complex mixed signal chips and, ultimately, the development of a full size readout chip featuring a 400 × 400 pixel array with 50μm pitch. In August 2017, the collaboration submitted the large scale chip RD53A, integrating a matrix of 400 × 192 pixels and embodying three different analog front-end designs. This work discusses the characteristic of the RD53A chip, with some emphasis on the analog processors, and presents the first test results on the pixel array.
•High particle rates and radiation levels will be reached at the HL-LHC.•New pixel chips for the phase II upgrades of CMS and ATLAS are required.•The RD53A chip has been designed in the framework of the RD53 Collaboration.•Three analog front-ends flavors are integrated in RD53A.•The paper presents the main preliminary results coming from RD53A characterization.
The Silicon strip sensors in high energy physics collider experiments have excellent capabilities of vertexing and tracking of incoming particles produced as a result of collision. These sensors are ...placed in intense radiation environment and hence undergo severe bulk and surface radiation damage. In order to operate these detectors with good physics performance, they must be subjected to stringent tolerance limits for their design parameters. These design parameters include global, strip and inter-strip parameters. The sensors are characterized for these parameters in temperature and humidity controlled environment, which are then accepted or rejected based on the constraints imposed on these parameters offered by a specific experiment.Our group at the University of Delhi is engaged in the process of developing a silicon sensor quality control centre for testing a large number of silicon micro-strip sensors. The primary objective of this facility is the qualification of these sensors for the outer tracker of the CMS experiment in High-Luminosity LHC upgrade. The system consists of a probe station and a set of electrical characterization units. The entire system is interfaced through the Automated Characterization Suite (ACS) software which allows the automatic characterization of the whole multistrip sensor without any manual intervention. The set-up has been under testing for measurements involving global, strip and inter-strip parameters. In this work, we present the details of this characterization system and measurements performed on some silicon strip sensors. To calibrate our setup the same set of measurements are performed with the setup available at the University of Pisa, Italy. The measurements performed using these two setups are found to be consistent with each other.
This document summarises the current theoretical and experimental status of the di-Higgs boson production searches, and of the direct and indirect constraints on the Higgs boson self-coupling, with ...the wish to serve as a useful guide for the next years. The document discusses the theoretical status, including state-of-the-art predictions for di-Higgs cross sections, developments on the effective field theory approach, and studies on specific new physics scenarios that can show up in the di-Higgs final state. The status of di-Higgs searches and the direct and indirect constraints on the Higgs self-coupling at the LHC are presented, with an overview of the relevant experimental techniques, and covering all the variety of relevant signatures. Finally, the capabilities of future colliders in determining the Higgs self-coupling are addressed, comparing the projected precision that can be obtained in such facilities. The work has started as the proceedings of the Di-Higgs workshop at Colliders, held at Fermilab from the 4th to the 9th of September 2018, but it went beyond the topics discussed at that workshop and included further developments.
The RD53A large scale pixel demonstrator chip has been developed in 65 nm CMOS technology by the RD53 collaboration, in order to face the unprecedented design requirements of the pixel 2 phase ...upgrades of the CMS and ATLAS experiments at CERN. This prototype chip is designed to demonstrate that a set of challenging specifications can be met, such as: high granularity (small pixels of 50×50 or 25× 100 µm 2 ) and large pixel chip size (~2x2 cm 2 ), high hit rate (3 GHz/cm 2 ), high readout speed, very high radiation levels (500 Mrad - 1 Grad) and operation with serial powering. Furthermore, coping with the long latency of the trigger signal (~12.5 µs), used to select only events of interest in order to achieve sustainable output data rates, requires increased buffering resources in the limited pixel area. The RD53A chip has been fabricated in an engineer run. It integrates a matrix of 400×192 pixels and features various design variations in the analog and digital pixel matrix for testing purposes. This paper presents an overview of the chip architecture and of the methodologies used for efficient design of large complex mixed signal chips for harsh radiation environments. Experimental results obtained from the characterization of the RD53A chip are reported to demonstrate that design objectives have been achieved. Moreover, design improvements and new features being developed in the RD53B framework for final ATLAS and CMS production chips are discussed.
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