D. Soldi

A bstract The NA62 experiment reports the branching ratio measurement $$ \mathrm{BR}\left({K}^{+}\to {\pi}^{+}\nu \overline{\nu}\right)=\left({10.6}_{-3.4}^{+4.0}\left|{}_{\mathrm{stat}}\right.\pm {0.9}_{\mathrm{syst}}\right)\times {10}^{-11} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>BR</mml:mi> <mml:mfenced> <mml:mrow> <mml:msup> <mml:mi>K</mml:mi> <mml:mo>+</mml:mo> </mml:msup> <mml:mo>→</mml:mo> <mml:msup> <mml:mi>π</mml:mi> <mml:mo>+</mml:mo> </mml:msup> <mml:mi>ν</mml:mi> <mml:mover> <mml:mi>ν</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:mrow> </mml:mfenced> <mml:mo>=</mml:mo> <mml:mfenced> <mml:mrow> <mml:msubsup> <mml:mn>10.6</mml:mn> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>3.4</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>4.0</mml:mn> </mml:mrow> </mml:msubsup> <mml:mfenced> <mml:msub> <mml:mrow /> <mml:mtext>stat</mml:mtext> </mml:msub> </mml:mfenced> <mml:mo>±</mml:mo> <mml:msub> <mml:mn>0.9</mml:mn> <mml:mtext>syst</mml:mtext> </mml:msub> </mml:mrow> </mml:mfenced> <mml:mo>×</mml:mo> <mml:msup> <mml:mn>10</mml:mn> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>11</mml:mn> </mml:mrow> </mml:msup> </mml:math> at 68% CL, based on the observation of 20 signal candidates with an expected background of 7.0 events from the total data sample collected at the CERN SPS during 2016–2018. This provides evidence for the very rare K + → $$ {\pi}^{+}\nu \overline{\nu} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mi>π</mml:mi> <mml:mo>+</mml:mo> </mml:msup> <mml:mi>ν</mml:mi> <mml:mover> <mml:mi>ν</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:math> decay, observed with a significance of 3.4 σ . The experiment achieves a single event sensitivity of (0 . 839 ± 0 . 054) × 10 − 11 , corresponding to 10.0 events assuming the Standard Model branching ratio of (8 . 4 ± 1 . 0) × 10 − 11 . This measurement is also used to set limits on BR( K + → π + X ), where X is a scalar or pseudo-scalar particle. Details are given of the analysis of the 2018 data sample, which corresponds to about 80% of the total data sample.

The NA62 experiment at CERN reports searches for $K^+\to\mu^+N$ and $K^+\to\mu^+\nu X$ decays, where $N$ and $X$ are massive invisible particles, using the 2016-2018 data set. The $N$ particle is assumed to be a heavy neutral lepton, and the results are expressed as upper limits of ${\cal O}(10^{-8})$ of the neutrino mixing parameter $|U_{\mu4}|^2$ for $N$ masses in the range 200-384 MeV/$c^2$ and lifetime exceeding 50 ns. The $X$ particle is considered a scalar or vector hidden sector mediator decaying to an invisible final state, and upper limits of the decay branching fraction for $X$ masses in the range 10-370 MeV/$c^2$ are reported for the first time, ranging from ${\cal O}(10^{-5})$ to ${\cal O}(10^{-7})$. An improved upper limit of $1.0\times 10^{-6}$ is established at 90% CL on the $K^+\to\mu^+\nu\nu\bar\nu$ branching fraction.

The NA62 experiment at the CERN SPS reports the first search for $K^+ \rightarrow \pi^+ \nu \bar{\nu}$ using the decay-in-flight technique, based on a sample of $1.21\times10^{11}$ $K^+$ decays collected in 2016. The single event sensitivity is $3.15\times 10^{-10}$, corresponding to 0.267 Standard Model events. One signal candidate is observed while the expected background is 0.152 events. This leads to an upper limit of $14 \times 10^{-10}$ on the $K^+ \rightarrow \pi^+ \nu \bar{\nu}$ branching ratio at 95\% CL.

A search for heavy neutral lepton (N) production in K+→e+N decays using the data sample collected by the NA62 experiment at CERN in 2017–2018 is reported. Upper limits of the extended neutrino mixing matrix element |Ue4|2 are established at the level of 10−9 over most of the accessible heavy neutral lepton mass range 144–462 MeV/c2, with the assumption that the lifetime exceeds 50 ns. These limits improve significantly upon those of previous production and decay searches. The |Ue4|2 range favoured by Big Bang Nucleosynthesis is excluded up to a mass of about 340 MeV/c2.

The integrated low-level trigger and data acquisition (TDAQ) system of the NA62 experiment at CERN is described. The requirements of a large and fast data reduction in a high-rate environment for a medium-scale, distributed ensemble of many different sub-detectors led to the concept of a fully digital integrated system with good scaling capabilities. The NA62 TDAQ system is rather unique in allowing full flexibility on this scale, allowing in principle any information available from the detector to be used for triggering. The design concept, implementation and performances from the first years of running are illustrated.

The NA62 experiment at CERN reports a search for the lepton number violating decays K+→π−e+e+ and K+→π−μ+μ+ using a data sample collected in 2017. No signals are observed, and upper limits on the branching fractions of these decays of 2.2×10−10 and 4.2×10−11 are obtained, respectively, at 90% confidence level. These upper limits improve on previously reported measurements by factors of 3 and 2, respectively.

The NA62 experiment at the CERN SPS reports a study of a sample of $4 \times10^{9}$ tagged $\pi^0$ mesons from $K^+ \to \pi^+ \pi^0 (\gamma)$, searching for the decay of the $\pi^0$ to invisible particles. No signal is observed in excess of the expected background fluctuations. An upper limit of $4.4 \times10^{-9}$ is set on the branching ratio at 90% confidence level, improving on previous results by a factor of 60. This result can also be interpreted as a model-independent upper limit on the branching ratio for the decay $K^+ \to \pi^+ X$, where $X$ is a particle escaping detection with mass in the range 0.110-0.155 GeV$/c^2$ and rest lifetime greater than 100 ps. Model-dependent upper limits are obtained assuming $X$ to be an axion-like particle with dominant fermion couplings or a dark scalar mixing with the Standard Model Higgs boson.

A bstract A search for the K + → π + X decay, where X is a long-lived feebly interacting particle, is performed through an interpretation of the K + → $$ {\pi}^{+}\nu \overline{\nu} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mi>π</mml:mi> <mml:mo>+</mml:mo> </mml:msup> <mml:mi>ν</mml:mi> <mml:mover> <mml:mi>ν</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:math> analysis of data collected in 2017 by the NA62 experiment at CERN. Two ranges of X masses, 0–110 MeV /c 2 and 154–260 MeV /c 2 , and lifetimes above 100 ps are considered. The limits set on the branching ratio, BR( K + → π + X ), are competitive with previously reported searches in the first mass range, and improve on current limits in the second mass range by more than an order of magnitude.

The high-luminosity phase of operation of the CERN Large Hadron Collider (HL-LHC) will pose new challenges to the detectors and their readout electronics. In particular, the Compact Muon Solenoid (CMS) barrel electromagnetic calorimeter will require a full redesign of the electronic readout chain in order to cope with the increase in luminosity and trigger rate. In this framework, a new application-specific integrated circuit (ASIC) integrating A/D conversion, lossless data compression, and high-speed transmission has been developed and tested. The ASIC, named Lisboa-Torino Ecal Data Transmission Unit (LiTE-DTU), is designed in a commercial CMOS 65-nm process and embeds two 12-bit, 160-MS/s analog-to-digital converters (ADCs), a data selection and compression logic, and a 1.28-Gb/s output serial link. The high-speed 1.28-GHz clock is generated internally from the 160-MHz input by a clock multiplication phase-locked loop (PLL). The circuit has been designed implementing radiation-tolerant techniques in order to work in the harsh environment of the HL-LHC upgrade. The LiTE-DTU is currently in the preproduction phase. A sample of 600 chips has been tested and incorporated into front-end (FE) boards for systems performance testing.

A bstract The NA62 experiment reports an investigation of the $$ {K}^{+}\to {\pi}^{+}\nu \overline{\nu} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mi>K</mml:mi> <mml:mo>+</mml:mo> </mml:msup> <mml:mo>→</mml:mo> <mml:msup> <mml:mi>π</mml:mi> <mml:mo>+</mml:mo> </mml:msup> <mml:mi>ν</mml:mi> <mml:mover> <mml:mi>ν</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:math> mode from a sample of K + decays collected in 2017 at the CERN SPS. The experiment has achieved a single event sensitivity of (0 . 389 ± 0 . 024) × 10 − 10 , corresponding to 2.2 events assuming the Standard Model branching ratio of (8 . 4 ± 1 . 0) × 10 − 11 . Two signal candidates are observed with an expected background of 1.5 events. Combined with the result of a similar analysis conducted by NA62 on a smaller data set recorded in 2016, the collaboration now reports an upper limit of 1 . 78 × 10 − 10 for the $$ {K}^{+}\to {\pi}^{+}\nu \overline{\nu} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mi>K</mml:mi> <mml:mo>+</mml:mo> </mml:msup> <mml:mo>→</mml:mo> <mml:msup> <mml:mi>π</mml:mi> <mml:mo>+</mml:mo> </mml:msup> <mml:mi>ν</mml:mi> <mml:mover> <mml:mi>ν</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:math> branching ratio at 90% CL. This, together with the corresponding 68% CL measurement of ( $$ {0.48}_{-0.48}^{+0.72} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mn>0.48</mml:mn> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.48</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.72</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> ) × 10 − 10 , are currently the most precise results worldwide, and are able to constrain some New Physics models that predict large enhancements still allowed by previous measurements.

The NA62 experiment at CERN, designed to study the ultra-rare decay $K^+ \to \pi^+\nu\overline{\nu}$, has also collected data in beam-dump mode. In this configuration, dark photons may be produced by protons dumped on an absorber and reach a decay volume beginning 80 m downstream. A search for dark photons decaying in flight to $\mu^+\mu^-$ pairs is reported, based on a sample of $1.4 \times 10^{17}$ protons on dump collected in 2021. No evidence for a dark photon signal is observed. A region of the parameter space is excluded at 90% CL, improving on previous experimental limits for dark photon masses between 215 and 550 MeV$/c^2$.

A bstract The NA62 experiment at CERN, designed to study the ultra-rare decay K + → π + $$ \nu \overline{\nu} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>ν</mml:mi> <mml:mover> <mml:mi>ν</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:math> , has also collected data in beam-dump mode. In this configuration, dark photons may be produced by protons dumped on an absorber and reach a decay volume beginning 80 m downstream. A search for dark photons decaying in flight to μ + μ − pairs is reported, based on a sample of 1 . 4 × 10 17 protons on dump collected in 2021. No evidence for a dark photon signal is observed. A region of the parameter space is excluded at 90% CL, improving on previous experimental limits for dark photon masses between 215 and 550 MeV /c 2 .

Abstract We have observed a significant enhancement in the energy deposition by 25– $$100~\textrm{GeV}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>100</mml:mn> <mml:mspace /> <mml:mtext>GeV</mml:mtext> </mml:mrow> </mml:math> photons in a $$1~\textrm{cm}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>1</mml:mn> <mml:mspace /> <mml:mtext>cm</mml:mtext> </mml:mrow> </mml:math> thick tungsten crystal oriented along its $$\langle 111 \rangle $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mo>⟨</mml:mo> <mml:mn>111</mml:mn> <mml:mo>⟩</mml:mo> </mml:mrow> </mml:math> lattice axes. At $$100~\textrm{GeV}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>100</mml:mn> <mml:mspace /> <mml:mtext>GeV</mml:mtext> </mml:mrow> </mml:math> , this enhancement, with respect to the value observed without axial alignment, is more than twofold. This effect, together with the measured huge increase in secondary particle generation is ascribed to the acceleration of the electromagnetic shower development by the strong axial electric field. The experimental results have been critically compared with a newly developed Monte Carlo adapted for use with crystals of multi- $$X_0$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>X</mml:mi> <mml:mn>0</mml:mn> </mml:msub> </mml:math> thickness. The results presented in this paper may prove to be of significant interest for the development of high-performance photon absorbers and highly compact electromagnetic calorimeters and beam dumps for use at the energy and intensity frontiers.

Abstract The NA62 experiment at CERN utilises a differential Cherenkov counter with achromatic ring focus (CEDAR) for tagging kaons within an unseparated monochromatic beam of charged hadrons. The CEDAR-H detector was developed to minimise the amount of material in the path of the beam by using hydrogen gas as the radiator medium. The detector was shown to satisfy the kaon tagging requirements in a test-beam before installation and commissioning at the experiment. The CEDAR-H performance was measured using NA62 data collected in 2023.

The NA62 experiment is designed to measure the ultra-rare decay K+ arrow π+ ν branching ratio with a precision of ∼ 10% at the CERN Super Proton Synchrotron (SPS). The trigger system of NA62 consists in three different levels designed to select events of physics interest in a high beam rate environment. The L0 Trigger Processor (L0TP) is the lowest level system of the trigger chain. It is hardware implemented using programmable logic. The architecture of the NA62 L0TP system is a new approach compared to existing systems used in high-energy physics experiments. It is fully digital, based on a standard gigabit Ethernet communication between detectors and the L0TP Board. The L0TP Board is a commercial development board, mounting a programmable logic device (FPGA). The primitives generated by sub-detectors are sent asynchronously using the UDP protocol to the L0TP during the entire beam spill period. The L0TP realigns in time the primitives coming from seven different sources and performs a data selection based on the characteristics of the event such as energy, multiplicity and topology of hits in the sub-detectors. It guarantees a maximum latency of 1 ms. The maximum input rate is about 10 MHz for each sub-detector, while the design maximum output trigger rate is 1 MHz. A description of the trigger algorithm is presented here.

Abstract The readout electronics for the CMS electromagnetic calorimeter is undergoing a re-design in order to cope with the LHC ugrade. In particular, a fourfold increase in the sampling frequency (from 40 to 160 MS/s) is required. Therefore a new readout ASIC has been developed. The ASIC, named LiTE-DTU, is designed in a CMOS 65 nm technology. The LiTE-DTU embeds two 12 bit, 160 MS/s ADCs, a time window based sample selection, lossless data compression and 1.28 Gb/s serialization. An on-chip PLL provides the 1.28 GHz clock required by the ADCs and the serializers from the 160 MHz clock.

In the NA62 experiment at CERN, the intense flux of particles requires a high-performance trigger for the data acquisition system. A Level 0 Trigger Processor (L0TP) was realized, performing the event selection based on trigger primitives coming from sub-detectors and reducing the trigger rate from 10 to 1 MHz. The L0TP is based on a commercial FPGA device and has been implemented in two different solutions. The performance of the two systems are highlighted and compared.

In the NA62 experiment at CERN-SPS the communication between detectors and the Lowest Level (L0) trigger processor is performed via Ethernet packets, using the UDP protocol. The L0 Trigger Processor handles the signals from sub-detectors that take part to the trigger generation. In order to choose the best solution for its realization, two different approaches have been implemented. The first approach is fully based on a FPGA device while the second one joins an off-the-shelf PC to the FPGA. The performance of the two systems will be discussed and compared.

The NA62 experiment at the CERN-SPS is designed to study the K + → π <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> νν ultra-rare decay using a high intensity hadron beam and detecting its decay products. The lowest level (Level-0, L0) trigger processor represents a crucial component in reducing the event rate, estimated to be about 10 MHz for most of the sub-detectors which form the trigger, by a factor 10 with a maximum admitted latency of 1 ms. For the realization of the trigger selection, two different approaches were developed. A first project is fully based on FPGA, in which the whole logic for data selection is hardware programmed, while the second one joins an off-the-shelf PC to the FPGA for greater flexibility in trigger programming. Development, test results and performances during NA62 data taking will be presented.

Abstract The NA62 experiment at the CERN SPS aims to measure the branching ratio of the very rare kaon decay <?CDATA ${K}^{+}\to {\pi }^{+}\nu \bar{\nu }$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:msup> <mml:mrow> <mml:mi>K</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> </mml:mrow> </mml:msup> <mml:mo>→</mml:mo> <mml:msup> <mml:mrow> <mml:mi>π</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> </mml:mrow> </mml:msup> <mml:mi>ν</mml:mi> <mml:mrow> <mml:mover accent="true"> <mml:mrow> <mml:mi>ν</mml:mi> </mml:mrow> <mml:mo>¯</mml:mo> </mml:mover> </mml:mrow> </mml:math> . The Calorimetric Level 0 Trigger identifies clusters in the electromagnetic and hadronic calorimeters. Along with the trigger data sent to the L0 Trigger Processor, readout data is collected to be sent to the L1 software trigger. In this work we present the novel implementation of the readout data collection and forwarding system in the multiple layers of the calorimetric trigger structure. We will also present the commissioning of the system and the performance evaluation on current data taking.

The NA62 experiment at the CERN SPS aims to measure the branching ratio of the very rare kaon decay $K^+ \rightarrow \pi^+ \nu \bar{\nu}$, collecting $\sim 100$ events with a 10\% background to make a stringent test of the Standard Model. The calorimeter level 0 trigger is used to suppress one of the main backgrounds, the $K^+ \rightarrow \pi^+ \pi^0$ decay, and to select events with a $\pi^+$ in the final state. The calorimeter level 0 trigger identifies clusters in the electromagnetic and hadronic calorimeters. It prepares time-ordered lists of reconstructed clusters together with the arrival time, position, and energy measurements of each cluster. It also provides trigger decisions based on complex combinations of energy and cluster multiplicity. The main parameters of the trigger processor are the high design hit rate (30 MHz) and the required single cluster time resolution (1.5 ns). The calorimeter trigger processor is a parallel system composed of 37 boards, 111 mezzanines and 221 high-performance programmable devices housed in three 9U crates. The design, operation and performances of the calorimeter level 0 trigger are presented.

The NA62 experiment at CERN SPS is aimed at measuring the branching ratio of the the very rare kaon decay Kpnn. NaNet is the reconfigurable design of a FPGA-based PCI Express Network Interface Card with processing, RDMA and GPUDirect capabilities, supporting multiple link technologies. NaNet has been employed to implement a real-time distributed processing pipeline in the the low level trigger of the experiment, operating on the data streams produced by the RICH detector with an orchestrated combination of heterogeneous computing devices (CPUs, FPGAs and GPUs). Recent results collected during NA62 runs are presented and discussed.

The L0TP+ initiative is aimed at the upgrade of the FPGA-based Level-0 Trigger Processor (L0TP) of the NA62 experiment at CERN for the post-LS2 data taking, which is expected to happen at 100% of design beam intensity, corresponding to about 3.3 × 10 12 protons per pulse on the beryllium target used to produce the kaons beam. Although tests performed at the end of 2018 showed a substantial robustness of the L0TP system also at full beam intensity, there are several reasons to motivate such an upgrade: i) avoid FPGA platform obsolescence, ii) make room for improvements in the firmware design leveraging a more capable FPGA device, iii) add new functionalities, iv) support the 4 beam intensity increase foreseen in future experiment upgrades. We singled out the Xilinx Virtex UltraScale+ VCU118 development board as the ideal platform for the project. L0TP+ seamless integration into the current NA62 TDAQ system and exact matching of L0TP functionalities represent the main requirements and focus of the project; nevertheless, the final design will include additional features, such as a PCIe RDMA engine to enable processing on CPU and GPU accelerators, and the partial reconfiguration of trigger firmware starting from a high level language description (C/C++). The latter capability is enabled by modern High Level Synthesis (HLS) tools, but to what extent this methodology can be applied to perform complex tasks in the L0 trigger, with its stringent latency requirements and the limits imposed by single FPGA resources, is currently being investigated. As a test case for this scenario we considered the online reconstruction of the RICH detector rings on an HLS generated module, using a dedicated primitives data stream with PM hits IDs. Besides, the chosen platform supports the Virtex Ultrascale+ FPGA wide I/O capabilities, allowing for straightforward integration of primitive streams from additional sub-detectors in order to improve the performance of the trigger.

The main purpose of the NA62 experiment is to measure the branching ratio of the (ultra) rare decay $K+ \rightarrow {\pi}+{\nu}\bar{\nu}$ with the precision of 10% collecting about 100 events with the Standard Model branching fraction in 3 years of data taking. The commissioning of the experiment after the 2014 pilot run and the prospects for the 2015 run are presented.

The main purpose of the NA62 experiment is to measure the branching ratio of the (ultra) rare decay $K+ \rightarrow {\pi}+{\nu}\bar{\nu}$ with the precision of 10% collecting about 100 events with the Standard Model branching fraction in 3 years of data taking. The commissioning of the experiment after the 2014 pilot run and the prospects for the 2015 run are presented.

The NA62 experiment is designed to measure the (ultra-)rare decay K+→π+νν¯ branching ratio with a precision of ∼10% at the CERN Super Proton Synchrotron (SPS). The L0 Trigger Processor (L0TP) is the lowest level system of the trigger chain. It is hardware implemented using programmable logic. The architecture of the L0TP is completely new for a high energy physics experiment. It is fully digital, based on a standard gigabit ethernet communication between detectors and L0TP Board. The L0TP Board is a commercial development board, Terasic DE4, mounting an Altera Stratix IV FPGA. The primitives generated by sub-detectors are sent asynchronously using the UDP protocol to the L0TP during the entire beam spill period (about 5 seconds). The L0TP realigns in time the primitives coming from 7 different sources and manages the information of the time plus all the characteristics of the event as energy, multiplicity and position of hits in order to select good events with a comparison with preset masks. It should guarantee a maximum latency of 1 ms. The maximum input rate is 10 MHz for each sub-detector, while the design maximum output trigger rate is 1 MHz. A complete trigger-less parasitic acquisition of the primitives is possible using mirroring switches to monitor the L0 behavior. A first version of the L0TP was commissioned during the 2014 NA62 pilot run and it is used in the current data taking. A description of the trigger algorithm is here presented.

The NA62 experiment at the CERN SPS aims at measuring the branching ratio of the very rare kaon decay K+ → π+ ν (expected 10−10) with a 10% background. Since an high-intensity kaon beam is required to collect enough statistics, the Level-0 trigger plays a fundamental role in both the background rejection and in the particle identification. The calorimetric trigger collects data from various calorimeters and it is able to identify clusters of energy deposit and determine their position, fine-time and energy. This paper describes the trigger system setup during the 2016 physics data taking. A newly implemented cluster counting algorithm is also presented.

K+ → π+v⊽ is one of the theoretically cleanest meson decay where to look for indirect effects of new physics complementary to LHC searches. The NA62 experiment at the CERN SPS is designed to measure the branching ratio of this decay with 10% precision. NA62 took data in pilot runs in 2014 and 2015 reaching the final designed beam intensity. The quality of data acquired in view of the final measurement will be presented.

The Electromagnetic Calorimeter (ECAL) of the CMS detector has played an important role in the physics program of the experiment, delivering outstanding performance throughout data taking.The High-Luminosity LHC will pose new challenges.The four to five-fold increase of the number of interactions per bunch crossing will require superior time resolution and noise rejection capabilities.For these reasons the electronics readout has been completely redesigned.A dual gain trans-impedance amplifier and an ASIC providing two 160 MHz ADC channels, gain selection, and data compression will be used in the new readout electronics.The trigger decision will be moved off-detector and will be performed by powerful and flexible FPGA processors, allowing for more sophisticated trigger algorithms to be applied.The upgraded ECAL will be capable of high-precision energy measurements throughout HL-LHC and will greatly improve the time resolution for photons and electrons above 10 GeV.The results in terms of performance achieved with a prototype system in a vertical integration test will be presented.

Abstract A new FPGA-based low-level trigger processor has been installed at the NA62 experiment. It is intended to extend the features of its predecessor due to a faster interconnection technology and additional logic resources available on the new platform. With the aim of improving trigger selectivity and exploring new architectures for complex trigger computation, a GPU system has been developed and a neural network on FPGA is in progress. They both process data streams from the ring imaging Cherenkov detector of the experiment to extract in real time high level features for the trigger logic. Description of the systems, latest developments and design flows are reported in this paper.

The CMS experiment at the LHC is equipped with a high granularity lead tungstate crystal electromagnetic calorimeter (ECAL) offering an excellent energy resolution.The ECAL was crucial in the discovery and subsequent characterization of the Higgs boson, particularly in the two photon and two Z boson decay channels.The LHC has reached an unprecedented luminosity during Run 2 (2016-2018), leading to a high numbers of proton-proton interactions per bunch collision (pileup), exceeding the design value and resulting in a very high radiation environment.We will present how we maintain the high performance of the calorimeter in these difficult conditions, challenging for both the calibration and the reconstruction.A new readout is being developed to operate the calorimeter at the high-luminosity LHC (HL-LHC) with an even higher luminosity, reaching an average pileup of up to 200.Precise signal time measurement and limitation of the dark current induced by radiation damaged are key ingredients to maintain a high energy resolution in the HL-LHC conditions.This upgrade of the CMS electromagnetic calorimeter will be presented.