Helium identification with LHCb

arXiv preprint arXiv:2404.19510

The four decays, , are observed for the first time using proton-proton collision data collected with the LHCb detector at a centre-of-mass energy of , corresponding to an integrated luminosity of . By considering the decay as reference channel, the following branching fraction ratios are measured to be, $$\frac{\cal{B} (\Lambda_{b}^{0} \rightarrow \Sigma_{c}^{++} \rm{D}^{-} {K}^{-})}{\cal{B}(\Lambda_{b}^{0} \rightarrow \Lambda_c^{+} \rm \overline{D}^0 {K}^{-})} = {0.282}\pm{0.016}\pm{0.016}\pm{0.005}, \frac{\cal{B}(\Lambda_{b}^{0} \rightarrow \Sigma_{c}^{*++} \rm {D}^{-} {K}^{-})}{\cal{B}(\Lambda_{b}^{0} \rightarrow \Sigma_c^{++} \rm {D}^{-} {K}^{-})} = {0.460}\pm{0.052}\pm{0.028}, \frac{\cal{B}(\Lambda_{b}^{0} \rightarrow \Sigma_{c}^{++} \rm {D}^{*-} {K}^{-})}{\cal{B}(\Lambda_{b}^{0} \rightarrow \Sigma_c^{++} \rm {D}^{-} {K}^{-})} = {2.261}\pm{0.202}\pm{0.129}\pm{0.046}, \frac{\cal{B}(\Lambda_{b}^{0} \rightarrow \Sigma_{c}^{*++} \rm D^{*-} K^{-})}{\cal{B}(\Lambda_{b}^{0} \rightarrow \Sigma_c^{++} \rm D^{-} K^{-})} = {0.896}\pm{0.137}\pm{0.066}\pm{0.018},$$ where the first uncertainties are statistical, the second are systematic, and the third are due to uncertainties in the branching fractions of intermediate particle decays. These initial observations mark the beginning of pentaquark searches in these modes, with more data set to become available following the LHCb upgrade.

arXiv preprint arXiv:2310.12278

The production rate of baryons relative to mesons in collisions at a center-of-mass energy TeV is measured by the LHCb experiment. The ratio of to production cross-sections shows a significant dependence on both the transverse momentum and the measured charged-particle multiplicity. At low multiplicity, the ratio measured at LHCb is consistent with the value measured in collisions, and increases by a factor of with increasing multiplicity. At relatively low transverse momentum, the ratio of to cross-sections is higher than what is measured in collisions, but converges with the ratio as the momentum increases. These results imply that the evolution of heavy quarks into final-state hadrons is influenced by the density of the hadronic environment produced in the collision. Comparisons with a statistical hadronization model and implications for the mechanisms enforcing quark confinement are discussed.

Physical Review C

The production of η and η′ mesons is studied in proton-proton and proton-lead collisions collected with the LHCb detector. Proton-proton collisions are studied at center-of-mass energies of 5.02 and 13 TeV and proton-lead collisions are studied at a center-of-mass energy per nucleon of 8.16 TeV. The studies are performed in center-of-mass (cm) rapidity regions 2.5< y c. m.< 3.5 (forward rapidity) and− 4.0< y c. m.<− 3.0 (backward rapidity) defined relative to the proton beam direction. The η and η′ production cross sections are measured differentially as a function of transverse momentum for 1.5< p T< 10 GeV and 3< p T< 10 GeV, respectively. The differential cross sections are used to calculate nuclear modification factors. The nuclear modification factors for η and η′ mesons agree at both forward and backward rapidity, showing no significant evidence of mass dependence. The differential cross sections of η …

Journal of High Energy Physics

A measurement of CP-violating observables in B±→ D* K±and B±→ D* π±decays is made where the photon or neutral pion from the D*→ Dγ or D*→ Dπ 0 decay is not reconstructed. The D meson is reconstructed in the self-conjugate decay modes, D→ π+ π− or D→ K+ K−. The distribution of signal yields in the D decay phase space is analysed in a model-independent way. The measurement uses a data sample collected in proton-proton collisions at centre-of-mass energies of 7, 8, and 13 TeV, corresponding to a total integrated luminosity of approximately 9 fb− 1. The B±→ D* K±and B±→ D* π±CP-violating observables are interpreted in terms of hadronic parameters and the CKM angle γ, resulting in a measurement of γ=(). The total uncertainty includes the statistical and systematic uncertainties, and the uncertainty due to external strong-phase inputs.

Physical Review Letters

A measurement of time-dependent CP violation in the decays of B 0 and B 0 mesons to the final states J/ψ (→ μ+ μ−) K S 0, ψ (2S)(→ μ+ μ−) K S 0 and J/ψ (→ e+ e−) K S 0 with K S 0→ π+ π− is presented. The data correspond to an integrated luminosity of 6 fb− 1 collected at a center-of-mass energy of√ s= 13 TeV with the LHCb detector. The CP-violation parameters are measured to be S ψK S 0= 0.717±0.013 (stat)±0.008 (syst) and C ψK S 0= 0.008±0.012 (stat)±0.003 (syst). This measurement of S ψK S 0 represents the most precise single measurement of the CKM angle β to date and is more precise than the current world average. In addition, measurements of the CP-violation parameters of the individual channels are reported and a combination with the LHCb Run 1 measurements is performed.

Physical review letters

The decay-time-dependent C P asymmetry in B s 0→ J/ψ (→ μ+ μ−) K+ K− decays is measured using proton-proton collision data, corresponding to an integrated luminosity of 6 fb− 1, collected with the LHCb detector at a center-of-mass energy of 13 TeV. Using a sample of approximately 349 000 B s 0 signal decays with an invariant K+ K− mass in the vicinity of the ϕ (1020) resonance, the C P-violating phase ϕ s is measured, along with the difference in decay widths of the light and heavy mass eigenstates of the B s 0− Bs 0 system, Δ Γ s, and the difference of the average B s 0 and B 0 meson decay widths, Γ s− Γ d. The values obtained are ϕ s=− 0.039±0.022±0.006 rad, Δ Γ s= 0.0845±0.0044±0.0024 ps− 1, and Γ s− Γ d=− 0.05 6− 0.0015+ 0.0013±0.0014 ps− 1, where the first uncertainty is statistical and the second systematic. These are the most precise single measurements to date and are consistent with …

arXiv preprint arXiv:1612.08110

A search for the charmless decay is performed using collision data collected by the LHCb experiment at centre-of-mass energies of and TeV, corresponding to an integrated luminosity of 3 fb. No signal is observed and upper limits on the branching fraction are set to at and at confidence level.

arXiv preprint arXiv:2312.03130

DUNE is an international experiment dedicated to addressing some of the questions at the forefront of particle physics and astrophysics, including the mystifying preponderance of matter over antimatter in the early universe. The dual-site experiment will employ an intense neutrino beam focused on a near and a far detector as it aims to determine the neutrino mass hierarchy and to make high-precision measurements of the PMNS matrix parameters, including the CP-violating phase. It will also stand ready to observe supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. The DUNE far detector implements liquid argon time-projection chamber (LArTPC) technology, and combines the many tens-of-kiloton fiducial mass necessary for rare event searches with the sub-centimeter spatial resolution required to image those events with high precision. The addition of a photon detection system enhances physics capabilities for all DUNE physics drivers and opens prospects for further physics explorations. Given its size, the far detector will be implemented as a set of modules, with LArTPC designs that differ from one another as newer technologies arise. In the vertical drift LArTPC design, a horizontal cathode bisects the detector, creating two stacked drift volumes in which ionization charges drift towards anodes at either the top or bottom. The anodes are composed of perforated PCB layers with conductive strips, enabling reconstruction in 3D. Light-trap-style photon detection modules are placed both on the cryostat's side walls and on the central cathode where they are …

Journal of High Energy Physics

The first measurement of the Z boson production cross-section at centre-of-mass energy= 5. 02 TeV in the forward region is reported, using pp collision data collected by the LHCb experiment in year 2017, corresponding to an integrated luminosity of 100±2 pb− 1. The production cross-section is measured for final-state muons in the pseudorapidity range 2. 0< η< 4. 5 with transverse momentum p T> 20 GeV/c. The integrated cross-section is determined to be

JOURNAL OF HIGH ENERGY PHYSICS

Null, N., Aaij, R., Abdelmotteleb, A., Abellan Beteta, C., Abudinén, F., Ackernley, T., et al.(2024). Study of Bc⁺→ χc π⁺ decays. JOURNAL OF HIGH ENERGY PHYSICS, 2024 (2)[10.1007/jhep02 (2024) 173].

European Physical Journal C

Hadrons are systems of quarks bound by the strong interaction, described at the fundamental level by quantum chromodynamics (QCD). The production and decay of hadrons involve the nonperturbative regime of QCD, making calculations challenging. Much progress has been made in recent years in experimental and theoretical studies of beauty mesons, with the aim of testing the Standard Model and

Physical review letters

The decay-time-dependent C P asymmetry in B s 0→ J/ψ (→ μ+ μ−) K+ K− decays is measured using proton-proton collision data, corresponding to an integrated luminosity of 6 fb− 1, collected with the LHCb detector at a center-of-mass energy of 13 TeV. Using a sample of approximately 349 000 B s 0 signal decays with an invariant K+ K− mass in the vicinity of the ϕ (1020) resonance, the C P-violating phase ϕ s is measured, along with the difference in decay widths of the light and heavy mass eigenstates of the B s 0− Bs 0 system, Δ Γ s, and the difference of the average B s 0 and B 0 meson decay widths, Γ s− Γ d. The values obtained are ϕ s=− 0.039±0.022±0.006 rad, Δ Γ s= 0.0845±0.0044±0.0024 ps− 1, and Γ s− Γ d=− 0.05 6− 0.0015+ 0.0013±0.0014 ps− 1, where the first uncertainty is statistical and the second systematic. These are the most precise single measurements to date and are consistent with …

arXiv preprint arXiv:2401.07564

In order to stimulate new engagement and trigger some concrete studies in areas where further work would be beneficial towards fully understanding the physics potential of an Higgs / Top / Electroweak factory, we propose to define a set of focus topics. The general reasoning and the proposed topics are described in this document.

Journal of High Energy Physics

A measurement of CP-violating observables in B±→ D* K±and B±→ D* π±decays is made where the photon or neutral pion from the D*→ Dγ or D*→ Dπ 0 decay is not reconstructed. The D meson is reconstructed in the self-conjugate decay modes, D→ π+ π− or D→ K+ K−. The distribution of signal yields in the D decay phase space is analysed in a model-independent way. The measurement uses a data sample collected in proton-proton collisions at centre-of-mass energies of 7, 8, and 13 TeV, corresponding to a total integrated luminosity of approximately 9 fb− 1. The B±→ D* K±and B±→ D* π±CP-violating observables are interpreted in terms of hadronic parameters and the CKM angle γ, resulting in a measurement of γ=(). The total uncertainty includes the statistical and systematic uncertainties, and the uncertainty due to external strong-phase inputs.

arXiv preprint arXiv:2402.01568

Doping of liquid argon TPCs (LArTPCs) with a small concentration of xenon is a technique for light-shifting and facilitates the detection of the liquid argon scintillation light. In this paper, we present the results of the first doping test ever performed in a kiloton-scale LArTPC. From February to May 2020, we carried out this special run in the single-phase DUNE Far Detector prototype (ProtoDUNE-SP) at CERN, featuring 770 t of total liquid argon mass with 410 t of fiducial mass. The goal of the run was to measure the light and charge response of the detector to the addition of xenon, up to a concentration of 18.8 ppm. The main purpose was to test the possibility for reduction of non-uniformities in light collection, caused by deployment of photon detectors only within the anode planes. Light collection was analysed as a function of the xenon concentration, by using the pre-existing photon detection system (PDS) of ProtoDUNE-SP and an additional smaller set-up installed specifically for this run. In this paper we first summarize our current understanding of the argon-xenon energy transfer process and the impact of the presence of nitrogen in argon with and without xenon dopant. We then describe the key elements of ProtoDUNE-SP and the injection method deployed. Two dedicated photon detectors were able to collect the light produced by xenon and the total light. The ratio of these components was measured to be about 0.65 as 18.8 ppm of xenon were injected. We performed studies of the collection efficiency as a function of the distance between tracks and light detectors, demonstrating enhanced uniformity of response for the anode-mounted PDS …

arXiv preprint arXiv:2402.01336

Measurements of the branching fraction ratio with and decays, denoted and , are presented. The analysis is performed using a dataset corresponding to an integrated luminosity of 5.4 of collision data collected with the LHCb experiment. The branching fractions are normalised with respect to the and decay modes. The combination of the results yields The result is compatible with previous measurements of the branching fractions and predictions based on the Standard Model.

Physical review letters

A measurement of time-dependent C P violation in the decays of B 0 and B 0 mesons to the final states J/ψ (→ μ+ μ−) K S 0, ψ (2 S)(→ μ+ μ−) K S 0 and J/ψ (→ e+ e−) K S 0 with K S 0→ π+ π− is presented. The data correspond to an integrated luminosity of 6 fb− 1 collected at a center-of-mass energy of s= 13 TeV with the LHCb detector. The C P-violation parameters are measured to be S ψ K S 0= 0.717±0.013 (stat)±0.008 (syst) and C ψ K S 0= 0.008±0.012 (stat)±0.003 (syst). This measurement of S ψ K S 0 represents the most precise single measurement of the CKM angle β to date and is more precise than the current world average. In addition, measurements of the C P-violation parameters of the individual channels are reported and a combination with the LHCb Run 1 measurements is performed.

arXiv preprint arXiv:2402.05523

The first observation of the decay is reported with high significance using proton-proton collision data, corresponding to an integrated luminosity of 9fb, collected with the LHCb detector at centre-of-mass energies of 7, 8, and 13 TeV. The ratio of its branching fraction relative to the channel is measured to be $$ \frac{ {\cal{B}}( B_c^+ \to J/\psi \pi^+\pi^0 ) } { {\cal{B}}( B_c^+ \to J/\psi \pi^+ ) } = 2.80 \pm 0.15 \pm 0.11 \pm 0.16 \,, $$ where the first uncertainty is statistical, the second systematic and the third related to imprecise knowledge of the branching fractions for and decays, which are used to determine the detection efficiency. The mass spectrum is found to be consistent with the dominance of an intermediate contribution in accordance with a model based on QCD factorisation.

Journal of Instrumentation

An imaging technique utilizing a scintillator plate in conjunction with a magnifying unit and a cooled electron multiplying charge-coupled device (EM-CCD) camera shows promise for capturing high-resolution trajectory images. Nevertheless, in the 2-dimensional trajectory images, the incident directions of the alpha particles entering the scintillator plate remained unknown due to the line-shaped trajectories. To elucidate the incident directions in our trajectory images, we conducted experiments capturing trajectory images of alpha particles under off-focus conditions. To capture off-focus images of alpha particles, we systematically varied the distance between the GAGG plate and the lens during imaging using an americium-241 (Am-241) source. Through images obtained at different distances between the GAGG plate and the lens, we successfully acquired trajectory images with varying degrees of off-focus …

Journal of Instrumentation

The complexity of modern cosmic ray observatories and the rich data sets they capture often require a sophisticated software framework to support the simulation of physical processes, detector response, as well as reconstruction and analysis of real and simulated data. Here we present the EUSO-Offline framework. The code base was originally developed by the Pierre Auger Collaboration, and portions of it have been adopted by other collaborations to suit their needs. We have extended this software to fulfill the requirements of Ultra-High Energy Cosmic Ray detectors and very high energy neutrino detectors developed for the Joint Exploratory Missions for an Extreme Universe Observatory (JEM-EUSO). These path-finder instruments constitute a program to chart the path to a future space-based mission like POEMMA. For completeness, we describe the overall structure of the framework developed by the Auger …

Journal of Instrumentation

The identification of helium nuclei at LHCb is achieved using a method based on measurements of ionisation losses in the silicon sensors and timing measurements in the Outer Tracker drift tubes. The background from photon conversions is reduced using the RICH detectors and an isolation requirement. The method is developed using ???????? collision data at

Journal of Instrumentation

The CMS Tracker Phase-2 Upgrade requires the production of new sensor modules to cope with the requirements of the HL-LHC. The two main building blocks of the Outer Tracker are the Strip-Strip and Pixel-Strip modules. All-together 47'520 hybrid circuits will be produced to construct 8'000 Strip-Strip and 5'880 Pixel-Strip modules. The circuit designs for the mass production were fine-tuned and kick-off batches were manufactured to verify the latest changes in the designs before the series production. This contribution focuses on lessons learned from the prototyping stage, design optimization details for the mass production as well as test results and production yield from the kick-off batches.

Journal of Instrumentation

The identification of helium nuclei at LHCb is achieved using a method based on measurements of ionisation losses in the silicon sensors and timing measurements in the Outer Tracker drift tubes. The background from photon conversions is reduced using the RICH detectors and an isolation requirement. The method is developed using ???????? collision data at

Journal of Instrumentation

Luminosity determination within the ALICE experiment is based on the measurement, in van der Meer scans, of the cross sections for visible processes involving one or more detectors (visible cross sections). In 2015 and 2018, the Large Hadron Collider provided Pb–Pb collisions at a centre-of-mass energy per nucleon pair of

Journal of Instrumentation

Luminosity determination within the ALICE experiment is based on the measurement, in van der Meer scans, of the cross sections for visible processes involving one or more detectors (visible cross sections). In 2015 and 2018, the Large Hadron Collider provided Pb–Pb collisions at a centre-of-mass energy per nucleon pair of

Journal of Instrumentation

Hydrogenated amorphous silicon (a-Si: H) is a material with a very good radiation hardness and with the possibility of deposition on flexible substrates like Polyimide (PI). Exploiting these properties, the HASPIDE (Hydrogenated Amorphous Silicon PIxels DEtectors) project has the goal of developing a-Si: H detectors on flexible substrates for beam dosimetry and profile monitoring, neutron detection and space experiments. The detectors for this experiment will be developed in two different structures: the nip diode structure, which has been used up to now for the construction of the planar a-Si: H detectors, and the recently developed charge selective contact structure. In the latter the doped layers (n or p) are replaced with charge selective materials namely electron-selective conductive metal-oxides (TiO 2 or Al: ZnO) and hole-selective conductive metal oxides (MoO x). In this paper preliminary data on the …

Journal of Instrumentation

Luminosity determination within the ALICE experiment is based on the measurement, in van der Meer scans, of the cross sections for visible processes involving one or more detectors (visible cross sections). In 2015 and 2018, the Large Hadron Collider provided Pb–Pb collisions at a centre-of-mass energy per nucleon pair of

Journal of Instrumentation

We propose for the first time, a new fuel-material for laser-driven Proton Boron (PB) fusion nuclear reactions. We propose, Hydrogen rich, Borane (B m H n) materials as fusion fuel as compared to Boron Nitride (BN) presently used. We estimate more than 10-fold increase in the yield of nuclear fusion reactions, and Alpha-prticle flux, when, for example Ammonia Borane (BNH 6) laser-target material will be used compared to the state of the art normalized flux∼ 10 8 Alphas/sr/J from BN targets. BNH 6 contains∼ 1000× higher concentration of Hydrogen compared to BN. We report the manufacture of the first solid-pellets Ammonia Borane laser-targets. To obtain high Flux Alpha sources from repetitive lasers we propose new BNH 6 target geometries: liquid (molten) droplets/jets; or translated tape-or disc-targets coated with BNH6 powder. Targets would be irradiated in low pressure, ambient buffer gas. To enhance the …

Journal of Instrumentation

The identification of helium nuclei at LHCb is achieved using a method based on measurements of ionisation losses in the silicon sensors and timing measurements in the Outer Tracker drift tubes. The background from photon conversions is reduced using the RICH detectors and an isolation requirement. The method is developed using ???????? collision data at

Journal of Instrumentation

Real-time dose-rate monitoring system under the high dose-rate situation is required for the decommissioning of Fukushima Daiichi Nuclear Plants to remove the debris remaining inside the plants. We have proposed a dose-rate monitor consisting of a scintillator, over 100-m long optical fiber and CCD spectrometer. Some noises with a dominant emission wavelength of below 550 nm originating from the optical fiber itself must be separated from the signal from the scintillator, and the signal region has been defined as 650–1000 nm to use significant data, up to now. In this paper, we investigated if the noise region defined as below 550 nm can be supporting data for the monitoring system, because such noises are expected to include position information through the fiber. In the emission spectrum, the intensities of the noise emission or absorption band are expected to depend on the position of the fiber, and we …

Journal of Instrumentation

Momentum measurements for very high momentum charged particles, such as muons from electroweak vector boson decays, are particularly susceptible to charge-dependent curvature biases that arise from misalignments of tracking detectors. Low momentum charged particles used in alignment procedures have limited sensitivity to coherent displacements of such detectors, and therefore are unable to fully constrain these misalignments to the precision necessary for studies of electroweak physics. Additional approaches are therefore required to understand and correct for these effects. In this paper the curvature biases present at the LHCb detector are studied using the pseudomass method in proton-proton collision data recorded at centre of mass energy

Journal of Instrumentation

Transmission muography is a non-invasive imaging technique that exploits the penetrating power of atmospheric muons into matter to obtain two-dimensional and three-dimensional density images of the monitored structure. The detectors used are particle trackers. Muography enables the monitoring of large structures and it is also particularly useful in the archaeological field for a mapping of low-density underground anomalies potentially related to unknown or inaccessible tombs or tunnels. The Palazzone necropolis, located south of Perugia (Italy), dating back to Etruscan period, contains about 200 known tombs, some of which, such as the Volumni Hypogeum, can be visited thanks to a touristic route. The eastern area of the necropolis, on the other hand, does not have a touristic path and is partially unknown. The objective of the muographic measurement campaign is to support the re-evaluation of this …

Journal of Instrumentation

Momentum measurements for very high momentum charged particles, such as muons from electroweak vector boson decays, are particularly susceptible to charge-dependent curvature biases that arise from misalignments of tracking detectors. Low momentum charged particles used in alignment procedures have limited sensitivity to coherent displacements of such detectors, and therefore are unable to fully constrain these misalignments to the precision necessary for studies of electroweak physics. Additional approaches are therefore required to understand and correct for these effects. In this paper the curvature biases present at the LHCb detector are studied using the pseudomass method in proton-proton collision data recorded at centre of mass energy

Journal of Instrumentation

Transmission muography is a non-invasive imaging technique that exploits the penetrating power of atmospheric muons into matter to obtain two-dimensional and three-dimensional density images of the monitored structure. The detectors used are particle trackers. Muography enables the monitoring of large structures and it is also particularly useful in the archaeological field for a mapping of low-density underground anomalies potentially related to unknown or inaccessible tombs or tunnels. The Palazzone necropolis, located south of Perugia (Italy), dating back to Etruscan period, contains about 200 known tombs, some of which, such as the Volumni Hypogeum, can be visited thanks to a touristic route. The eastern area of the necropolis, on the other hand, does not have a touristic path and is partially unknown. The objective of the muographic measurement campaign is to support the re-evaluation of this …

Journal of Instrumentation

Instruments based on light obscuration sensors are widely used for measuring the size distribution of insoluble sub-visible particles in liquid suspensions, being fast and suitable for in situ and real-time measurements. Such instruments are typically calibrated by means of reference polystyrene spherical particles with a specific refractive index, which unavoidably leads to systematic errors when determining the size of particles of different materials. In this paper, we propose a reliable and consistent method to overcome this limitation by setting the refractive index value according to the sample, thus achieving an improved particle size distribution (PSD) measurement. An ad hoc, ready-to-use, open source code with a graphical interface able to drive an in-line instrument and obtain a real-time correction to the PSD has been developed. The method has been extensively validated with several oil emulsions …

Journal of Instrumentation

The Deep Underground Neutrino Experiment (DUNE) is a next generation experiment aimed to study neutrino oscillation. Its long-baseline configuration will exploit a Near Detector (ND) and a Far Detector (FD) located at a distance of∼ 1300 km. The FD will consist of four Liquid Argon Time Projection Chamber (LAr TPC) modules. A Photon Detection System (PDS) will be used to detect the scintillation light produced inside the detector after neutrino interactions. The PDS will be based on light collectors coupled to Silicon Photomultipliers (SiPMs). Different photosensor technologies have been proposed and produced in order to identify the best samples to fullfill the experiment requirements. In this paper, we present the procedure and results of a validation campaign for the Hole Wire Bonding (HWB) MPPCs samples produced by Hamamatsu Photonics KK (HPK) for the DUNE experiment, referring to them …

Journal of Instrumentation

Thanks to their advantages in terms of easiness of manufacturing and reduced production costs, Monolithic Active Pixel Sensors (MAPS) represent an appealing solution for radiation imaging applications, which require to cover large areas with pixelated detectors. In the next upgrade of the ALICE detector, that will have to deal with the higher event rate resulting from the planned increase in the LHC luminosity, it is foreseen to include two additional sensor layers to perform Time of Flight (ToF) measurements. Trying to reach the challenging timing resolution required by the ALICE ToF layers, an internal gain layer has been included in the test structures of the third engineering run of the ARCADIA project to improve the timing performance of this MAPS technology. In the paper we will present an overview of the main results obtained from the electrical and the dynamic characterization of the fabricated devices, which …

Journal of Instrumentation

Liquid Argon (LAr) Time Projection Chambers (TPC) operating in double-phase can detect the nuclear recoils (NR) possibly caused by the elastic scattering of WIMP dark matter particles via light signals from both scintillation and ionization processes. In the scenario of a low-mass WIMP (< 2 GeV/c 2), the energy range for the NRs would be below 20 keV, thus making it crucial to characterize the ionization response in LAr TPCs as the lone available detection channel at such low energy. The Recoil Directionality (ReD) project, within the Global Argon Dark Matter Collaboration, aims to measure the ionization yield of a LAr TPC in the recoil energy range of 2–5 keV. The measurement was performed in winter 2023 at the INFN Sezione of Catania and the analysis is ongoing.