The Experimental Cavern North 3 (ECN3) is an underground experimental cavern on the CERN Pr\'evessin site. ECN3 currently hosts the NA62 experiment, with a physics programme devoted to rare kaon decays and searches of hidden particles approved until Long Shutdown 3 (LS3). Several options are proposed on the longer term in order to make best use of the worldwide unique potential of the high-intensity/high-energy proton beam extracted from the Super Proton Synchrotron (SPS) in ECN3. The current status of their study by the CERN Physics Beyond Colliders (PBC) Study Group is presented, including considerations on beam requirements and upgrades, detector R&D and construction, schedules and cost, as well as physics potential within the CERN and worldwide landscape.

A bstract A search for the exclusive decays of the Higgs and Z bosons to a ϕ or ρ meson and a photon is performed with a pp collision data sample corresponding to an integrated luminosity of up to 35 . 6 fb −1 collected at $$ \sqrt{s}=13 $$ s = 13 TeV with the ATLAS detector at the CERN Large Hadron Collider. These decays have been suggested as a probe of the Higgs boson couplings to light quarks. No significant excess of events is observed above the background, as expected from the Standard Model. Upper limits at 95% confidence level were obtained on the branching fractions of the Higgs boson decays to ϕ γ and ρ γ of 4 . 8 × 10 −4 and 8 . 8 × 10 −4 , respectively. The corresponding 95% confidence level upper limits for the Z boson decays are 0 . 9 × 10 −6 and 25 × 10 −6 for ϕ γ and ρ γ, respectively.

A search for leptoquarks decaying into the bτ final state is performed using Run 2 proton-proton collision data from the Large Hadron Collider, corresponding to an integrated luminosity of 139 fb−1 at √(s) = 13 TeV recorded by the ATLAS detector. The benchmark models considered in this search are vector leptoquarks with electric charge of 2/3e and scalar leptoquarks with an electric charge of 4/3e. No significant excess above the Standard Model prediction is observed, and 95

The total and differential Higgs boson production cross-sections are measured through a combined statistical analysis of the H → ZZ* → 4ℓ and H → γγ decay channels. The results are based on a dataset of 139 fb−1 of proton–proton collisions at a centre-of-mass energy of 13 TeV, recorded by the ATLAS detector at the Large Hadron Collider. The measured total Higgs boson production cross-section is 55.5_-3.8^+4.0 pb, consistent with the Standard Model prediction of 55.6 ± 2.5 pb. All results from the two decay channels are compatible with each other, and their combination agrees with the Standard Model predictions. A combined statistical interpretation of the measured fiducial cross-sections as a function of the Higgs boson transverse momentum is performed in order to probe the Yukawa couplings to the bottom and charm quarks. A similar interpretation is performed by including also the constraints from the measurements of Higgs boson production in association with a W or Z boson in the H → bb and cc decay channels.

Against the background of global geopolitical turmoil and the deterioration of relations with the overwhelming number of Western countries that have amicably united for the purpose of unfriendly actions against Russia, a discussion on the development of cooperation with the People's Republic of China has been widely developed. Will the Celestial Empire be able, and most importantly, will it want to become a full-fledged replacement for the West in our economic life?

Depleted Monolithic Active Pixel Sensors (DMAPS) are monolithic pixel detectors with high-resistivity substrates designed for use in high-rate and highradiation environments.They are produced in commercial CMOS processes, resulting in relatively low production costs and short turnaround times, and offer a low material budget.LF-Monopix1 and TJ-Monopix1 are large DMAPS prototypes produced in 150 nm LFoundry and 180 nm TowerJazz technology, respectively, that follow two different design concepts regarding the charge collection electrode.Prototypes of both development lines have been extensively tested and characterized over the last years.The second-generation Monopix prototypes, Monopix2, were recently produced.They were designed to address the shortcomings of their predecessors, in particular related to radiation hardness and cross talk, and further improve upon their performance.The latest measurements with LF-Monopix1 and TJ-Monopix1 concerning hit efficiency, depletion, and radiation hardness as well as the initial test results of the new Monopix2 prototypes are presented.

The LF-Monopix chips are depleted monolithic active pixel sensors that follow the large-electrode design approach and implement a fast synchronous read-out architecture. They are designed in a 150 nm CMOS process and make use of large voltages (>250V) and highly resistive substrates (>2k Omega center dot cm) to collect charge through drift and enhance their radiation hardness. Samples of the first prototype ("LF-Monopix1'') with a thickness of 100 mu m were irradiated to assess the tolerance of the chip's substrate and front-end circuitry to the surface and bulk damage doses expected at modern collider experiments. The device remained fully operational, with only a very small gain degradation and an increase in noise by less than 25% after a total ionizing dose of 100 Mrad. Efficiency measurements in a sample exposed to a neutron fluence of 1 x 10(15) n(eq)/cm(2) showed that at least 96% of all minimum ionizing particles going through a fully depleted detector are recorded in less than 25 ns. In the latest design ("LF-Monopix2'') the column length was tripled and the pixel pitch reduced by 40% with respect to its predecessor. The chip was successfully thinned down while keeping its breakdown voltage above 400V and achieving a front-end threshold dispersion of similar to 100e(-) after tuning.

The situations in Syria, Ukraine, Libya, Nagorno-Karabakh, Iraq and other countries, which gave rise to the largest forced resettlement in the entire history of the United Nations, convince us that today the problem of ensuring the protection of the rights of refugees in armed conflicts is one of the most urgent in the world.

In this chapter we will present the results of the impact of radiation on electronics and opto-electronics for two of the LHC experiments during Run 1 and Run 2. ATLAS results are presented in Section 6.1; CMS in Section 6.2. In Section 6.3 we will present a comparison between the two experiments, highlighting operational guidelines and proposing solutions to build the electronics and opto-electronics of the future LHC experiments.

This letter presents a search for narrow, high-mass resonances in the Zγ final state with the Z boson decaying into a pair of electrons or muons. The s=13 TeV pp collision data were recorded by the ATLAS detector at the CERN Large Hadron Collider and have an integrated luminosity of 140 fb−1. The data are found to be in agreement with the Standard Model background expectation. Upper limits are set on the resonance production cross section times the decay branching ratio into Zγ. For spin-0 resonances produced via gluon–gluon fusion, the observed limits at 95% confidence level vary between 65.5 fb and 0.6 fb, while for spin-2 resonances produced via gluon–gluon fusion (or quark–antiquark initial states) limits vary between 77.4 (76.1) fb and 0.6 (0.5) fb, for the mass range from 220 GeV to 3400 GeV.

The first measurement of longitudinal decorrelations of harmonic flow amplitudes v_{n} for n=2-4 in Xe+Xe collisions at sqrt[s_{NN}]=5.44  TeV is obtained using 3  μb^{-1} of data with the ATLAS detector at the LHC. The decorrelation signal for v_{3} and v_{4} is found to be nearly independent of collision centrality and transverse momentum (p_{T}) requirements on final-state particles, but for v_{2} a strong centrality and p_{T} dependence is seen. When compared with the results from Pb+Pb collisions at sqrt[s_{NN}]=5.02  TeV, the longitudinal decorrelation signal in midcentral Xe+Xe collisions is found to be larger for v_{2}, but smaller for v_{3}. Current hydrodynamic models reproduce the ratios of the v_{n} measured in Xe+Xe collisions to those in Pb+Pb collisions but fail to describe the magnitudes and trends of the ratios of longitudinal flow decorrelations between Xe+Xe and Pb+Pb. The results on the system-size dependence provide new insights and an important lever arm to separate effects of the longitudinal structure of the initial state from other early and late time effects in heavy-ion collisions.

The Physics Beyond Colliders initiative is an exploratory study aimed at exploiting the full scientific potential of the CERN's accelerator complex and scientific infrastructures through projects complementary to the LHC and other possible future colliders. These projects will target fundamental physics questions in modern particle physics. This document presents the status of the proposals presented in the framework of the Beyond the Standard Model physics working group, and explore their physics reach and the impact that CERN could have in the next 10-20 years on the international landscape.

Effects of Single Event Upsets (SEU) and Single Event Transients (SET) are studied in the FE-I4B chip of the innermost layer of the ATLAS pixel system. SEU/SET affect the FE-I4B Global Registers as well as the settings for the individual pixels, causing, among other things, occupancy losses, drops in the low voltage currents, noisy pixels, and silent pixels. Quantitative data analysis and simulations indicate that SET dominate over SEU on the load line of the memory. Operational issues and mitigation techniques are presented.

ATLAS is one of the four major experiments at the Large Hadron Collider at CERN. The tracking performance of the ATLAS detector relies critically on its 4-layer Pixel detector, located at the core the ATLAS tracker. During operation at instantaneous luminosities of up to 2.1 x 10(34) cm(-2) s(-1) the frontend chips of the ATLAS innermost pixel layer experienced single event upsets affecting their global registers as well as the settings for the individual pixels, causing, amongst other things, loss of occupancy, noisy pixels, and silent pixels. A quantitative analysis of the single event upsets as well as the operational issues and mitigation techniques are presented.

In the relatively recent CMS data, there is a hint on the existence of a resonance with the mass 28 GeV coupling to muons. Such a resonance should also couple to photons through the fermion loop, therefore it can be searched for in ultraperipheral collisions (UPC) of protons. We set an upper bound on the $X \gamma \gamma$ coupling constant from the data on $\mu^+ \mu^-$ pair production in UPC at the LHC. Our approach can be used for similar resonances should they appear in the future.

This paper presents a search for direct top squark pair production in events with missing transverse momentum plus either a pair of jets consistent with Standard Model Higgs boson decay into b-quarks or a same-flavour opposite-sign dilepton pair with an invariant mass consistent with a Z boson. The analysis is performed using the proton–proton collision data at \n$$\\sqrt{s}=13$$\n\n TeV collected with the ATLAS detector during the LHC Run-2, corresponding to an integrated luminosity of 139 fb\n$$^{-1}$$\n\n. No excess is observed in the data above the Standard Model predictions. The results are interpreted in simplified models featuring direct production of pairs of either the lighter top squark (\n$$\\tilde{t}_1$$\n\n) or the heavier top squark (\n$$\\tilde{t}_2$$\n\n), excluding at 95% confidence level \n$$\\tilde{t}_1$$\n\n and \n$$\\tilde{t}_2$$\n\n masses up to about 1220 and 875 GeV, respectively.

CMOS monolithic pixel detector technology is one of the options considered for the outer layer of an upgraded ATLAS pixel detector in 2026. In this upgrade pixel detector modules will be powered in series by a constant current source to reduce power losses and material budget. On-chip shunt regulators generate the local 1.8 V supply voltage from the input current to provide power to the integrated circuits. The sensor bias for monolithic sensors is often limited and not sufficiently large to allow a common bias for all sensors in the serial powering chain. In this paper, we give an introduction to the serial powering strategy for CMOS detectors with emphasis on the design and simulation results of a regulated charge pump circuit for sensor biasing. Two prototypes operating with a pumping frequency of 640 MHz, one with 6-stages and one with 19-stages, were designed and fabricated in a modified TowerJazz 0.18 μm CMOS imaging technology to provide negative bias down to − 6 V and − 20 V, respectively. Simulation results demonstrate good performance of the charge pump circuit which could be used to bias the CMOS sensor.

The Phase 2 upgrades of silicon pixel detectors at HL-LHC experiments feature extreme require- ments, such as: 50x50 μm pixels, high rate (3 GHz/cm2), unprecedented radiation levels (1 Grad), high readout speed and serial powering. As a consequence a new readout chip is required. In this framework the RD53 collaboration submitted RD53A, a large scale chip demonstrator de- signed in 65 nm CMOS technology, integrating a matrix of 400×192 pixels. It features design variations in the analog and digital pixel matrix for testing purposes. An overview of the building blocks will be given together with test results on single chips.

The production cross-sections for W +/- and Z bosons are measured using ATLAS data corresponding to an integrated luminosity of 4.0 pb-1 collected at a centre-ofmass energy v s = 2.76 TeV. The deca ...