Antonín Květoň

The COMPASS Collaboration experiment recently discovered a new isovector resonancelike signal with axial-vector quantum numbers, the ${a}_{1}(1420)$, decaying to ${f}_{0}(980)\ensuremath{\pi}$. With a mass too close to and a width smaller than the axial-vector ground state ${a}_{1}(1260)$, it was immediately interpreted as a new light exotic meson, similar to the $X$, $Y$, $Z$ states in the hidden-charm sector. We show that a resonancelike signal fully matching the experimental data is produced by the decay of the ${a}_{1}(1260)$ resonance into ${K}^{*}(\ensuremath{\rightarrow}K\ensuremath{\pi})\overline{K}$ and subsequent rescattering through a triangle singularity into the coupled ${f}_{0}(980)\ensuremath{\pi}$ channel. The amplitude for this process is calculated using a new approach based on dispersion relations. The triangle-singularity model is fitted to the partial-wave data of the COMPASS experiment. Despite having fewer parameters, this fit shows a slightly better quality than the one using a resonance hypothesis and thus eliminates the need for an additional resonance in order to describe the data. We thereby demonstrate for the first time in the light-meson sector that a resonancelike structure in the experimental data can be described by rescattering through a triangle singularity, providing evidence for a genuine three-body effect.

A set of measurements of azimuthal asymmetries in the production of pairs of identified hadrons in deep-inelastic scattering of muons on transversely polarised 6LiD (deuteron) and NH3 (proton) targets is presented. All available data collected in the years 2003–2004 and 2007/2010 with the COMPASS spectrometer using a muon beam of 160GeV/c at the CERN SPS were analysed. The asymmetries provide access to the transversity distribution functions via a fragmentation function that in principle may be independently obtained from e+e− annihilation data. Results are presented, discussed and compared to existing measurements as well as to model predictions. Asymmetries of π+π− pairs measured with the proton target as a function of the Bjorken scaling variable are sizeable in the range x>0.032, indicating non-vanishing transversity distribution and di-hadron interference fragmentation functions. As already pointed out by several authors, the small asymmetries of π+π− measured on the 6LiD target can be interpreted as indication for a cancellation of u and d-quark transversity distributions.

We study the spin-exotic ${J}^{PC}={1}^{\ensuremath{-}+}$ amplitude in single-diffractive dissociation of $190\text{ }\text{ }\mathrm{GeV}/c$ pions into ${\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$ using a hydrogen target and confirm the ${\ensuremath{\pi}}_{1}(1600)\ensuremath{\rightarrow}\ensuremath{\rho}(770)\ensuremath{\pi}$ amplitude, which interferes with a nonresonant ${1}^{\ensuremath{-}+}$ amplitude. We demonstrate that conflicting conclusions from previous studies on these amplitudes can be attributed to different analysis models and different treatment of the dependence of the amplitudes on the squared four-momentum transfer and we thus reconcile these experimental findings. We study the nonresonant contributions to the ${\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$ final state using pseudodata generated on the basis of a Deck model. Subjecting pseudodata and real data to the same partial-wave analysis, we find good agreement concerning the spectral shape and its dependence on the squared four-momentum transfer for the ${J}^{PC}={1}^{\ensuremath{-}+}$ amplitude and also for amplitudes with other ${J}^{PC}$ quantum numbers. We investigate for the first time the amplitude of the ${\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$ subsystem with ${J}^{PC}={1}^{\ensuremath{-}\ensuremath{-}}$ in the $3\ensuremath{\pi}$ amplitude with ${J}^{PC}={1}^{\ensuremath{-}+}$ employing the novel freed-isobar analysis scheme. We reveal this ${\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$ amplitude to be dominated by the $\ensuremath{\rho}(770)$ for both the ${\ensuremath{\pi}}_{1}(1600)$ and the nonresonant contribution. These findings largely confirm the underlying assumptions for the isobar model used in all previous partial-wave analyses addressing the ${J}^{PC}={1}^{\ensuremath{-}+}$ amplitude.

New results are presented on a high-statistics measurement of Collins and Sivers asymmetries of charged hadrons produced in deep inelastic scattering of muons on a transversely polarised $^6$LiD target. The data were taken in 2022 with the COMPASS spectrometer using the 160 \gevv\ muon beam at CERN, balancing the existing data on transversely polarised proton targets. The first results from about two-thirds of the new data have total uncertainties smaller by up to a factor of three compared to the previous deuteron measurements. Using all the COMPASS proton and deuteron results, both the transversity and the Sivers distribution functions of the $u$ and $d$ quark, as well as the tensor charge in the measured $x$-range are extracted. In particular, the accuracy of the $d$ quark results is significantly improved.

We report on a measurement of Spin Density Matrix Elements (SDMEs) in hard exclusive $\omega$ meson muoproduction on the proton at COMPASS using 160 GeV/$c$ polarised $ \mu ^{+}$ and $ \mu ^{-}$ beams impinging on a liquid hydrogen target. The measurement covers the range 5.0 GeV/$c^2$ $< W <$ 17.0 GeV/$c^2$, with the average kinematics $\langle Q^{2} \rangle=$ 2.1 (GeV/$c$)$^2$, $\langle W \rangle= 7.6$ GeV/$c^2$, and $\langle p^{2}_{\rm T} \rangle = 0.16$ (GeV/$c$)$^2$. Here, $Q^2$ denotes the virtuality of the exchanged photon, $W$ the mass of the final hadronic system and $p_T$ the transverse momentum of the $\omega$ meson with respect to the virtual-photon direction. The measured non-zero SDMEs for the transitions of transversely polarised virtual photons to longitudinally polarised vector mesons ($\gamma^*_T \to V_L$) indicate a violation of $s$-channel helicity conservation. Additionally, we observe a sizeable contribution of unnatural-parity-exchange (UPE) transitions that decreases with increasing $W$. The results provide important input for modelling Generalised Parton Distributions (GPDs). In particular, they may allow to evaluate in a model-dependent way the contribution of UPE transitions and assess the role of parton helicity-flip GPDs in exclusive $\omega$ production.

The production of vector mesons in deep inelastic scattering is an interesting yet scarsely explored channel to study the transverse spin structure of the nucleon and the related phenomena. The COMPASS collaboration has performed the first measurement of the Collins and Sivers asymmetries for inclusively produced $\rho^0$ mesons. The analysis is based on the data set collected in deep inelastic scattering in $2010$ using a $160\,\,\rm{GeV}/c$ $\mu^+$ beam impinging on a transversely polarized $\rm{NH}_3$ target. The $\rho^{0}$ mesons are selected from oppositely charged hadron pairs, and the asymmetries are extracted as a function of the Bjorken-$x$ variable, the transverse momentum of the pair and the fraction of the energy $z$ carried by the pair. Indications for positive Collins and Sivers asymmetries are observed.

Hadron leptoproduction in Semi-Inclusive measurements of Deep-Inelastic Scattering (SIDIS) on unpolarised nucleons allows one to get information on the intrinsic transverse momentum of quarks in a nucleon and on the Boer-Mulders function through the measurement of azimuthal modulations in the cross section. These modulations were recently measured by the HERMES experiment at DESY on proton and deuteron targets, and by the COMPASS experiment using the CERN SPS muon beam and a 6LiD target. In both cases, the amplitudes of the cos⁡ϕh and cos⁡2ϕh modulations show strong kinematic dependences for both positive and negative hadrons. It has been known since some time that the measured final-state hadrons in those SIDIS experiments receive a contribution from exclusive diffractive production of vector mesons, particularly important at large values of z, the fraction of the virtual photon energy carried by the hadron. In previous measurements of azimuthal asymmetries this contribution was not taken into account, because it was not known that it could distort the azimuthal modulations. Presently, a method to evaluate the contribution of the exclusive reactions to the azimuthal asymmetries measured by COMPASS has been developed. The subtraction of this contribution results in a better understanding of the kinematic effects, and the remaining non-zero cos⁡2ϕh modulation gives indication for a non-zero Boer-Mulders effect.

Using FPGA technology for event building tasks in high-energy physics experiments reduces costs and increases reliability of DAQ systems.In 2014, the COMPASS experiment at the Super Proton Synchrotron at CERN commissioned a novel, intelligent, FPGA-based DAQ in which event building is entirely performed by FPGA cards.The highly scalable system is designed to cope with an on-spill data rate of 1.5 GB/s and a sustained data rate of 500 MB/s.Its intelligent and highly reliable hardware event builder is able to handle and detect front-end errors and automatically take corrective action.In September 2017, it reached an uptime of 99.63%.The paper gives an overview of system details, performance, and running experience.

The antiparticle-over-particle multiplicity ratio is measured in deep-inelastic scattering for negatively and positively charged kaons and, for the first time, for antiprotons and protons. The data were obtained by the COMPASS Collaboration using a 160 GeV muon beam impinging on an isoscalar 6LiD target. The regime of deep-inelastic scattering is ensured by requiring Q2 > 1 (GeV/c)2 for the photon virtuality and W>5 GeV/c2 for the invariant mass of the produced hadronic system. Bjorken-x is restricted to the range 0.01 to 0.40. Protons and antiprotons are identified in the momentum range from 20 GeV/c to 60 GeV/c and required to carry a large fraction of the virtual-photon energy, z>0.5. In the whole studied z-region, the p¯ over p multiplicity ratio is found to be below the lower limit expected from calculations based on leading-order perturbative Quantum Chromodynamics (pQCD). Kaons were previously analysed in the momentum range 12 GeV/c to 40 GeV/c. In the present analysis this range is extended up to 55 GeV/c, whereby events with larger virtual-photon energies are included in the analysis and the observed K− over K+ ratio becomes closer to the expectation of next-to-leading order pQCD. The results of both analyses strengthen our earlier conclusion that at COMPASS energies the phase space available for single-hadron production in deep-inelastic scattering should be taken into account in the standard pQCD formalism.

The COMPASS Collaboration performed measurements of the Drell-Yan process in 2015 and 2018 using a 190 GeV/c $\pi^{-}$ beam impinging on a transversely polarised ammonia target. Combining the data of both years, we present final results on the amplitudes of the five azimuthal modulations in the dimuon production cross section. Three of these transverse-spin-dependent azimuthal asymmetries (TSAs) probe the nucleon leading-twist Sivers, transversity, and pretzelosity transverse-momentum dependent (TMD) parton distribution functions (PDFs). The other two are induced by subleading effects. These TSAs provide unique new inputs for the study of the nucleon TMD PDFs and their universality properties. In particular, the Sivers TSA observed in this measurement is consistent with the fundamental QCD prediction of a sign change of naive time-reversal-odd TMD PDFs when comparing the Drell-Yan process with semi-inclusive measurements of deep inelastic scattering. Also, within the context of model predictions, the observed transversity TSA is consistent with the expectation of a sign change for the Boer-Mulders function.

Abstract We report on a measurement of Spin Density Matrix Elements (SDMEs) in hard exclusive $$\rho ^0$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mi>ρ</mml:mi> <mml:mn>0</mml:mn> </mml:msup> </mml:math> meson muoproduction at COMPASS using 160 GeV/ c polarised $$ \mu ^{+}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mi>μ</mml:mi> <mml:mo>+</mml:mo> </mml:msup> </mml:math> and $$ \mu ^{-}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mi>μ</mml:mi> <mml:mo>-</mml:mo> </mml:msup> </mml:math> beams impinging on a liquid hydrogen target. The measurement covers the kinematic range 5.0 GeV/ $$c^2$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mi>c</mml:mi> <mml:mn>2</mml:mn> </mml:msup> </mml:math> $$&lt; W&lt;$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mo>&lt;</mml:mo> <mml:mi>W</mml:mi> <mml:mo>&lt;</mml:mo> </mml:mrow> </mml:math> 17.0 GeV/ $$c^2$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mi>c</mml:mi> <mml:mn>2</mml:mn> </mml:msup> </mml:math> , 1.0 (GeV/ c ) $$^2$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mrow /> <mml:mn>2</mml:mn> </mml:msup> </mml:math> $$&lt; Q^2&lt;$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mo>&lt;</mml:mo> <mml:msup> <mml:mi>Q</mml:mi> <mml:mn>2</mml:mn> </mml:msup> <mml:mo>&lt;</mml:mo> </mml:mrow> </mml:math> 10.0 (GeV/ c ) $$^2$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mrow /> <mml:mn>2</mml:mn> </mml:msup> </mml:math> and 0.01 (GeV/ c ) $$^2$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mrow /> <mml:mn>2</mml:mn> </mml:msup> </mml:math> $$&lt; p_{\textrm{T}}^2&lt;$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mo>&lt;</mml:mo> <mml:msubsup> <mml:mi>p</mml:mi> <mml:mrow> <mml:mtext>T</mml:mtext> </mml:mrow> <mml:mn>2</mml:mn> </mml:msubsup> <mml:mo>&lt;</mml:mo> </mml:mrow> </mml:math> 0.5 (GeV/ c ) $$^2$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mrow /> <mml:mn>2</mml:mn> </mml:msup> </mml:math> . Here, W denotes the mass of the final hadronic system, $$Q^2$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mi>Q</mml:mi> <mml:mn>2</mml:mn> </mml:msup> </mml:math> the virtuality of the exchanged photon, and $$p_{\textrm{T}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>p</mml:mi> <mml:mtext>T</mml:mtext> </mml:msub> </mml:math> the transverse momentum of the $$\rho ^0$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mi>ρ</mml:mi> <mml:mn>0</mml:mn> </mml:msup> </mml:math> meson with respect to the virtual-photon direction. The measured non-zero SDMEs for the transitions of transversely polarised virtual photons to longitudinally polarised vector mesons ( $$\gamma ^*_T \rightarrow V^{ }_L$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msubsup> <mml:mi>γ</mml:mi> <mml:mi>T</mml:mi> <mml:mo>∗</mml:mo> </mml:msubsup> <mml:mo>→</mml:mo> <mml:msubsup> <mml:mi>V</mml:mi> <mml:mi>L</mml:mi> <mml:mrow /> </mml:msubsup> </mml:mrow> </mml:math> ) indicate a violation of s -channel helicity conservation. Additionally, we observe a dominant contribution of natural-parity-exchange transitions and a very small contribution of unnatural-parity-exchange transitions, which is compatible with zero within experimental uncertainties. The results provide important input for modelling Generalised Parton Distributions (GPDs). In particular, they may allow one to evaluate in a model-dependent way the role of parton helicity-flip GPDs in exclusive $$\rho ^0$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mi>ρ</mml:mi> <mml:mn>0</mml:mn> </mml:msup> </mml:math> production.

We present a new data acquisition system for the COMPASS++/AMBER experiment designed as a further development of the intelligent FPGA-based data acquisition framework. The system is designed to have a maximum throughput of 5 GB/s. We designed the system to provide free-running continuous readout, which allows us to implement a sophisticated data filtering by delaying the decision until the hardware filter and high-level trigger stage which processes data. The system includes front-end cards, fully digital hardware filter, data multiplexers, a timeslice builder, and a high-level trigger farm. The data selection and data assembly require a time structure of the data streams with different granularity for different detectors. We define a unit of detector data as image and combine images from different detectors within a time window to timeslices. By routing data based on the timeslices, we can average data rates and easily achieve scalability. The main component that allows us to achieve these goals is a high-performance and cost-effective hardware timeslice builder. The timeslice builder combines streaming data by their time and consists of the data switch and the spillbuffer build. The scalable architecture allows us to increase the throughput of the system and achieve a true triggerless mode of operation.

We developed a novel free-running data acquisition system for the AMBER experiment.The system features a hybrid architecture containing a scalable FPGA-based system for data collection and conventional distributed computing for data reduction.The current implementation can collect up to 10 GB/s sustained data rate.The FPGA system substitutes high-performance networks by merging time-correlated data and distribution between computers.The data reduction is performed by a filtering farm decreasing the incoming data rate by a factor of 50 to 100-200 MB/s.The filtering framework implements various data reduction algorithms for different physics programs.These algorithms perform partial data decoding, time, and spatial analysis of the data in order to select predefined event topology in a semi-online manner.Our system also performs continuous and iterative time calibration of detectors, which is required by the continuously running acquisition system.Additionally, we developed a simulation tool able to emulate detector responses to particles passing the AMBER spectrometer and convert them into correctly formatted raw data.These generated data are used to test and validate the readout chain and the filtering framework.The entire system will be tested with a limited number of detectors this year.The first physics run is planned for 2024.

We study the light output, light collection efficiency and signal timing of a variety of organic scintillators that are being considered for the upgrade of the hadronic calorimeter of the CMS detector. The experimental data are collected at the H2 test-beam area at CERN, using a 150 GeV muon beam. In particular, we investigate the usage of over-doped and green-emitting plastic scintillators, two solutions that have not been extensively considered. We present a study of the energy distribution in plastic-scintillator tiles, the hit efficiency as a function of the hit position, and a study of the signal timing for blue and green scintillators.

Recently, a stability of Data Acquisition System (DAQ) has become a vital precondition for a successful data taking in high energy physics experiments. The intelligent, FPGA-based Data Acquisition System (iFDAQ) of the COMPASS experiment at CERN is designed to be able to readout data at the maximum rate of the experiment and runsin a mode without any stops. DAQ systems fulfilling such requirements reach the efficiency up to 99%. The newly introduced continuously running mode enables to collect data without a necessity of any other user intervention.Such mode affects all processes of the iFDAQ with high emphasis on timing and precise synchronization. However, every undesirable interruption of data taking can potentially result in a possible loss of physics data. Running24/7 puts stress on reliability and robustness of the system. Therefore, the improvement of the iFDAQ stability had to come first. The continuously running mode and the improved iFDAQ stability helped to collect more physicsdata in the Run 2017. In the paper, we present the continuously running mode in more detail and discuss the overall iFDAQ stability.

This contribution focuses on the deployment and first results of the new data acquisition system (DAQ) of the COMPASS experiment at CERN laboratory. The COMPASS experiment is a fixed target experiment with maximum rate of 1.5 GB/s. The DAQ utilizing FPGA-based event builder is designed to be able to readout data at maximum rate of the experiment. The DAQ is developed under name RCCARS (run control, configuration, and readout system). The RCCARS has been deployed for the pilot run starting from the September 2014 and further developed for long run in 2015. In the paper, we present performance and stability results of the new DAQ architecture; we compare it with the original system in more details.

The Phase I upgrade of the CMS Hadron Endcap Calorimeters consists of new photodetectors (Silicon Photomultipliers in place of Hybrid Photo-Diodes) and front-end electronics. The upgrade will eliminate the noise and the calibration drift of the Hybrid Photo-Diodes and enable the mitigation of the radiation damage of the scintillators and the wavelength shifting fibers with a larger spectral acceptance of the Silicon Photomultipliers. The upgrade also includes increased longitudinal segmentation of the calorimeter readout, which allows pile-up mitigation and recalibration due to depth-dependent radiation damage. As a realistic operational test, the responses of the Hadron Endcap Calorimeter wedges were calibrated with a 60Co radioactive source with upgrade electronics. The test successfully established the procedure for future source calibrations of the Hadron Endcap Calorimeters. Here we describe the instrumentation details and the operational experiences related to the sourcing test.

Modern experiments demand a powerful and efficient Data Acquisition System (DAQ). The intelligent, FPGA-based Data Acquisition System (iFDAQ) of the COMPASS experiment at CERN is composed of many processes communicating between each other. The DIALOG library covers a communication mechanism between processes and establishes a communication layer to each of them. It has been introduced to the iFDAQ in the Run 2016 and improved significantly the stability of the system. The paper presents the online monitoring API for the DIALOG library. Communication between processes is challenging from a synchronization, reliability and robustness point of view. Online monitoring tools of the communication between processes are capable to reveal communication problems to be fixed in future. The debugging purpose has been crucial during introduction period to the iFDAQ. On the other hand, based on the measurement of communication between processes, the proper load balancing of processes among machines can improve the stability of the system. The online monitoring API offers a general approach for the implementation of many monitoring tools with different purposes. In the paper, it is discussed its fundamental concept, integration to a new monitoring tool and a few examples of monitoring tools are given.

In general, state-of-the-art data acquisition systems in high energy physics experiments must satisfy high requirements in terms of reliability, efficiency and data rate capability. The paper introduces the Load Balancing (LB) problem of the intelligent, FPGA-based Data Acquisition System (iFDAQ) of the COMPASS experiment at CERN and proposes a solution based on genetic algorithms. Since the LB problem is N P-complete, it challenges analytical and heuristic methods in finding optimal solutions in reasonable time. Differential Evolution (DE) is a type of evolutionary algorithms, which has been used in many optimization problems due to its simplicity and efficiency. Therefore, the Modified Differential Evolution (MDE) is inspired by DE and is presented in more detail. The MDE algorithm has newly-designed crossover and mutation operator and its selection mechanism is inspired by Simulated Annealing (SA). Moreover, the proposal uses an adaptive scaling factor and recombination rate affecting the exploration and exploitation of the MDE algorithm. Thus, the MDE represents a new efficient stochastic search technique for the LB problem. The proposed MDE algorithm is examined on two LB test cases and compared with other LB solution methods.

We report on a measurement of Spin Density Matrix Elements (SDMEs) in hard exclusive $ω$ meson muoproduction on the proton at COMPASS using 160 GeV/$c$ polarised $ μ^{+}$ and $ μ^{-}$ beams impinging on a liquid hydrogen target. The measurement covers the range 5.0 GeV/$c^2$ $&lt; W &lt;$ 17.0 GeV/$c^2$, with the average kinematics $\langle Q^{2} \rangle=$ 2.1 (GeV/$c$)$^2$, $\langle W \rangle= 7.6$ GeV/$c^2$, and $\langle p^{2}_{\rm T} \rangle = 0.16$ (GeV/$c$)$^2$. Here, $Q^2$ denotes the virtuality of the exchanged photon, $W$ the mass of the final hadronic system and $p_T$ the transverse momentum of the $ω$ meson with respect to the virtual-photon direction. The measured non-zero SDMEs for the transitions of transversely polarised virtual photons to longitudinally polarised vector mesons ($γ^*_T \to V_L$) indicate a violation of $s$-channel helicity conservation. Additionally, we observe a sizeable contribution of unnatural-parity-exchange (UPE) transitions that decreases with increasing $W$. The results provide important input for modelling Generalised Parton Distributions (GPDs). In particular, they may allow to evaluate in a model-dependent way the contribution of UPE transitions and assess the role of parton helicity-flip GPDs in exclusive $ω$ production.

In HEP experiments, remote access to control systems is one of the fundamental pillars of efficient operations. At the same time, development of user interfaces with emphasis on usability can be one of the most labor-intensive software tasks to be undertaken in the life cycle of an experiment. While desirable, the development and maintenance of a large variety of interfaces (e.g., desktop control interface, web monitoring interface, development API...) is often simply not feasible, as far as manpower is concerned. We present a solution employed in the control software of the iFDAQ of the COMPASS experiment at CERN. Being a mix of a command-line and terminal tool, this interface can fulfill the roles of a dynamic monitoring interface, a control interface, and a scripting API simultaneously. Furthermore, it can easily be used as a remote access tool for operations experts, needing nearly no setup user-side and being compatible with smartphones. We also discuss the methodology and results of a concrete use case – automated run control for performance tests of the iFDAQ readout software.

Recently, a successful data taking in high energy physics experiments heavily relies on a stability of Data Acquisition System (DAQ). The paper deals with the Load Balancing (LB) problem of the intelligent, FPGA-based Data Acquisition System (iFDAQ) of the COMPASS experiment at CERN and presents two approaches –Dynamic Programming (DP) and Greedy Heuristic (GH) – applied in finding LB optimal solution. DP represents a pure mathematical approach in terms of a mathematical optimization and GH is a representative belonging to a class of heuristics. Therefore, the mutual comparison is worth investigating. In order to demonstrate the performance of the proposed DP and GH approaches, three LB test cases are examined and the numerical results are compared with other LB solution methods.

Triggered data acquisition systems provide only limited possibilities of triggering methods. In our paper, we propose a novel approach that completely removes the hardware trigger and its logic. It introduces an innovative free-running mode instead, which provides unprecedented possibilities to physics experiments. We would like to present such system, which is being developed for the AMBER experiment at CERN. It is based on an intelligent data acquisition framework including FPGA modules and advanced software processing. The system provides a triggerless mode that allows more time for data filtering and implementation of more complex algorithms. Moreover, it utilises a custom data protocol optimized for needs of the free-running system. The filtering procedure takes place in a server farm playing the role of the highlevel trigger. For this purpose, we introduce a high-performance filtering framework providing optimized algorithms and load balancing to cope with excessive data rates. Furthermore, this paper also describes the filter pipeline as well as the simulation chain that is being used for production of artificial data, for testing, and validation.