E. Di Marco

This white paper summarizes the workshop U.S. Cosmic Visions: New Ideas in Dark Matter held at University of Maryland on March 23-25, 2017.

The search for a novel technology able to detect and reconstruct nuclear and electron recoil events with the energy of a few keV has become more and more important now that large regions of high-mass dark matter (DM) candidates have been excluded. Moreover, a detector sensitive to incoming particle direction will be crucial in the case of DM discovery to open the possibility of studying its properties. Gaseous time projection chambers (TPC) with optical readout are very promising detectors combining the detailed event information provided by the TPC technique with the high sensitivity and granularity of latest-generation scientific light sensors. The CYGNO experiment (a CYGNus module with Optical readout) aims to exploit the optical readout approach of multiple-GEM structures in large volume TPCs for the study of rare events as interactions of low-mass DM or solar neutrinos. The combined use of high-granularity sCMOS cameras and fast light sensors allows the reconstruction of the 3D direction of the tracks, offering good energy resolution and very high sensitivity in the few keV energy range, together with a very good particle identification useful for distinguishing nuclear recoils from electronic recoils. This experiment is part of the CYGNUS proto-collaboration, which aims at constructing a network of underground observatories for directional DM search. A one cubic meter demonstrator is expected to be built in 2022/23 aiming at a larger scale apparatus (30 m3–100 m3) at a later stage.

The CYGNO project has the goal to use a gaseous TPC with optical readout to detect dark matter and solar neutrinos with low energy threshold and directionality. The CYGNO demonstrator will consist of 1 m 3 volume filled with He:CF 4 gas mixture at atmospheric pressure. Optical readout with high granularity CMOS sensors, combined with fast light detectors, will provide a detailed reconstruction of the event topology. This will allow to discriminate the nuclear recoil signal from the background, mainly represented by low energy electron recoils induced by radioactivity. Thanks to the high reconstruction efficiency, CYGNO will be sensitive to low mass dark matter, and will have the potential to overcome the neutrino floor, that ultimately limits non-directional dark matter searches.

Optical readout of GEM based devices by means of high granularity and low noise CMOS sensors allows to obtain very interesting tracking performance. Space resolution of the order of tens of μm were measured on the GEM plane along with an energy resolution of 20%÷30%. The main limitation of CMOS sensors is represented by their poor information about time structure of the event. In this paper, the use of a concurrent light readout by means of a suitable photomultiplier and the acquisition of the electric signal induced on the GEM electrode are exploited to provide the necessary timing informations. The analysis of the PMT waveform allows a 3D reconstruction of each single clusters with a resolution on z of 100 μm. Moreover, from the PMT signals it is possible to obtain a fast reconstruction of the energy released within the detector with a resolution of the order of 25% even in the tens of keV range useful, for example, for triggering purpose.

Time Projection Chambers (TPCs) working in combination with Gas Electron Multipliers (GEMs) produce a very sensitive detector capable of observing low energy events. This is achieved by capturing photons generated during the GEM electron multiplication process by means of a high-resolution camera. The CYGNO experiment has recently developed a TPC Triple GEM detector coupled to a low noise and high spatial resolution CMOS sensor. For the image analysis, an algorithm based on an adapted version of the well-known DBSCAN was implemented, called iDBSCAN. In this paper a description of the iDBSCAN algorithm is given, including test and validation of its parameters, and a comparison with DBSCAN itself and a widely used algorithm known as Nearest Neighbor Clustering (NNC). The results show that the adapted version of DBSCAN is capable of providing full signal detection efficiency and very good energy resolution while improving the detector background rejection.

Optical readout of large Time Projection Chambers (TPCs) with multiple Gas Electron Multipliers (GEMs) amplification stages has shown to provide very interesting performances for high energy particle tracking. Proposed applications for low-energy and rare event studies, such as Dark Matter search, ask for demanding performance in the keV energy range. The performance of such a readout was studied in details as a function of the electric field configuration and GEM gain by using a 55Fe source within a 7 litre sensitive volume detector developed as a part of the R&D for the CYGNUS project. Results reported in this paper show that the low noise level of the sensor allows to operate with a 2 keV threshold while keeping a rate of fake-events lesser than 10 per year. In this configuration, a detection efficiency well above 95% along with an energy resolution (σ) of 18% is obtained for the 5.9 keV photons demonstrating the very promising capabilities of this technique.

The search for a novel technology able to detect and reconstruct nuclear recoil events in the keV energy range has become more and more important as long as vast regions of high mass WIMP-like Dark Matter candidate have been excluded. Gaseous Time Projection Chambers (TPC) with optical readout are very promising candidate combining the complete event information provided by the TPC technique to the high sensitivity and granularity of last generation scientific light sensors. A TPC with an amplification at the anode obtained with Gas Electron Multipliers (GEM) was tested at the Laboratori Nazionali di Frascati. Photons and neutrons from radioactive sources were employed to induce recoiling nuclei and electrons with kinetic energy in the range [1-100] keV. A He-CF4 (60/40) gas mixture was used at atmospheric pressure and the light produced during the multiplication in the GEM channels was acquired by a high position resolution and low noise scientific CMOS camera and a photomultiplier. A multi-stage pattern recognition algorithm based on an advanced clustering technique is presented here. A number of cluster shape observables are used to identify nuclear recoils induced by neutrons originated from a AmBe source against X-ray 55Fe photo-electrons. An efficiency of 18% to detect nuclear recoils with an energy of about 6 keV is reached obtaining at the same time a 96% 55Fe photo-electrons suppression. This makes this optically readout gas TPC a very promising candidate for future investigations of ultra-rare events as directional direct Dark Matter searches.

Calibration of the relative response of the individual channels of the barrel electromagnetic calorimeter of the CMS detector was accomplished, before installation, with cosmic ray muons and test beams. One fourth of the calorimeter was exposed to a beam of high energy electrons and the relative calibration of the channels, the intercalibration, was found to be reproducible to a precision of about 0.3%. Additionally, data were collected with cosmic rays for the entire ECAL barrel during the commissioning phase. By comparing the intercalibration constants obtained with the electron beam data with those from the cosmic ray data, it is demonstrated that the latter provide an intercalibration precision of 1.5% over most of the barrel ECAL. The best intercalibration precision is expected to come from the analysis of events collected in situ during the LHC operation. Using data collected with both electrons and pion beams, several aspects of the intercalibration procedures based on electrons or neutral pions were investigated.

The CYGNO project aims at realizing a one cubic meter gaseous Time Projection Chamber (TPC) equipped with Scientific CMOS (sCMOS) commercial cameras to optically readout Gas Electron Multiplier (GEM) to be operated at the underground of Gran Sasso National Laboratory (LNGS). The purpose of the project is to study the technology needed for a large size gaseous TPC (30–100 m3) operated at atmospheric pressure for the directional search of low mass O(GeV) dark matter and low energy (eg solar) neutrinos astronomy. The roadmap of the project foresees the underground operation of a 50 litres TPC prototype, called LIME, the largest TPC realized with this technology, fully equipped with copper and water shielding. LIME is equivalent to about a 1/20 of the CYGNO demonstrator and aims to validate: The construction materials, the Monte Carlo simulations, the data reconstruction and the particle identification performances at low energy threshold. LIME is under installation at the LNGS and it is supposed to start data taking at the beginning of 2022. The detector description and installation will be presented, as well as the overground performance and limitations that require underground characterization.

The CYGNO project aims to develop a high-precision optical Time Projection Chamber (TPC) for directional Dark Matter search and solar neutrino spettroscopy, to be hosted at Laboratori Nazionali del Gran Sasso (LNGS). The distinctive feature of CYGNO include the exploitation of scientific CMOS cameras and photomultiplier tubes coupled to a Gas Electron Multiplier for amplification within helium-fluorine-based gas mixture at atmospheric pressure. The primary objective of this project is to achieve three-dimentional tracking with head-tail capability and to enhance background rejection down to the keV energy range. This enhancement will significantly improve sensitivity to low Weakly Interacting Massive Particle masses for both Spin-Independent and Spin-Dependent coupling. We provide insights into the commissioning and underground operation of our 50-liter prototype, known as LIME, which represents the largest prototype developed by our collaboration to date. We showcase its capability to measure and identify low-energy nuclear and electron recoils. Additionally, we outline the design and prospects for the development of a funded $\mathcal{O}(1\,\rm{m}^3)$ demonstrator, set to be housed in Hall F of LNGS. Furthermore, we present the physics potential that a future $\mathcal{O}(30\, \rm{m}^3)$ experiment could bring to the field. Lastly, we discuss the results from our collaboration's research and development efforts aimed at maximizing the potential of CYGNO. This includes the recent achievement of negative ion drift operation at atmospheric pressure with optical readout, which was accomplished in synergy with the ERC Consolidator Grant project INITIUM.

In this paper we build a comprehensive analysis framework to perform direct extraction of all possible effective Higgs couplings to neutral electroweak gauge bosons in the decay to electrons and muons, the so called `golden channel'. Our framework is based on a maximum likelihood method constructed from analytic expressions of the fully differential cross sections for $h \rightarrow 4\ell$ and for the dominant irreducible $q\bar{q} \rightarrow 4\ell$ background, where $4\ell = 2e2\mu, 4e, 4\mu$. Detector effects are included by an explicit convolution of these analytic expressions with the appropriate transfer function over all center of mass variables. Using the full set of decay observables, we construct an unbinned 8-dimensional detector-level likelihood function which is continuous in the effective couplings and includes systematic uncertainties. We consider all possible $ZZ$, $Z\gamma$ and $\gamma\gamma$ couplings, allowing for general CP odd/even admixtures and any possible phases. We describe how the convolution is performed and demonstrate the validity and power of the framework with a number of supporting checks and example fits. The framework can be used to perform a variety of multi-parameter extractions, including their correlations, to determine the Higgs couplings to neutral electroweak gauge bosons using data obtained at the LHC and other future colliders.

The R&D of a gas detector prototype for high precision tracking of low energy nuclear recoils over large volume is presented in this paper.The scintillation light accompanying the electronic avalanches in a triple GEM structure is detected by a CMOS-based camera.The sensor provides very high granularity along with a very low noise and high sensitivity.Space resolution of the order of tens of µm were measured on the GEM plane (xy).The Negative Ion Drift method to reconstruct the depth of track within the sensitive volume was studied.Recent tests on beam demonstrated the feasibility of the NID method with a small amount of SF 6 even at nearly ambient pressure.The use of a concurrent light readout by means of a suitable photomultiplier provides the necessary timing informations.A time resolution of the order of 5 ns was measured.

The performance and long term stability of an optically readout Time Projection Chamber with an electron amplification structure based on three Gas Electron Multipliers was studied. He/CF4 based gas mixtures were used in two different proportions (60/40 and 70/30) in a CYGNO prototype with 7 litres sensitive volume. With electrical configurations providing very similar electron gains, an almost full detection efficiency in the whole detector volume was found with both mixtures, while a light yield about 20% larger for the 60/40 was found. The electrostatic stability was tested by monitoring voltages and currents during 25 days. The detector worked in very stable and safe condition for the whole period. In the presence of less CF4, a larger probability of unstable events was clearly detected.

Ensuring the radiation hardness of PbWO4 crystals was one of the main priorities during the construction of the electromagnetic calorimeter of the CMS experiment at CERN. The production on an industrial scale of radiation hard crystals and their certification over a period of several years represented a difficult challenge both for CMS and for the crystal suppliers. The present article reviews the related scientific and technological problems encountered.

Cerium-doped Lutetium-Yttrium Oxyorthosilicate (LYSO:Ce)is one of the most widely used Cerium-doped Lutetium based scintillation crystals. Initially developed for medical detectors it rapidly became attractive for High Energy Particle Physics (HEP) applications, especially in the frame of high luminosity particle colliders. In this paper, a comprehensive and systematic study of LYSO:Ce ($[Lu_{(1-x)}Y_x]_2SiO_5$:$Ce$) crystals is presented. It involves for the first time a large number of crystal samples (180) of the same size from a dozen of producers.The study consists of a comparative characterization of LYSO:Ce crystal products available on the market by mechanical, optical and scintillation measurements and aims specifically, to investigate key parameters of timing applications for HEP.

The Time Projection Chamber (TPC) is an ideal candidate to finely study the charged particle ionization in a gaseous medium. Large volume TPCs can be readout with a suitable number of channels offering a complete 3D reconstruction of a charged particle track, that is the sequence of its energy releases in the TPC gas volume. Moreover, He-based TPCs are very promising to study keV energy particles as nuclear recoils, opening the possibility for directional searches of Dark Matter (DM) and the study of Solar Neutrinos (SN). In this paper we report the analysis of the data acquired with a small TPC prototype (named LEMOn) built by the CYGNO collaboration that was exposed to a beam of 450 MeV electrons at the Beam Test Facility of National Laboratories of Frascati. LEMOn is operated with a He-CF4 mixture at atmospheric pressure and is based on a Gas Electron Multipliers amplification stage that produces visible light collected by the high granularity and very good sensitivity of scientific CMOS camera. This type of readout – in conjunction with a fast light detection – allows a 3D reconstruction of the electrons tracks. The electrons are leaving a trail of clusters of ionizations corresponding to a few keV energy release each. Their study leads to predict a keV energy threshold and 1–10 mm longitudinal and 0.1–0.3 mm transverse position resolution (sigma) for nuclear recoils, very promising for the application of optically read out TPC to DM searches and SN measurements.

The BABAR detector has operated nearly 200 Resistive Plate Chambers (RPCs), constructed as part of an upgrade of the forward endcap muon detector, for the past two years.The RPCs experience widely different background and luminosity-driven singles rates (0.01-10 Hz/cm 2 ) depending on position within the endcap.Some regions have integrated over 0.3 C/cm 2 .RPC efficiency measured with cosmic rays is high and stable.The average efficiency measured with beam is also high.However, a few of the highest rate RPCs have suffered efficiency losses of 5-15%.Although constructed with improved techniques and minimal use of linseed oil, many of the RPCs, which are operated in streamer mode, have shown increased dark currents and noise rates that are correlated with the direction of the gas flow and the integrated current.Studies of the above aging effects are presented and correlated with detector operating conditions.

The performance of electromagnetic calorimeter modules made of proton-irradiated PbWO4 crystals has been studied in beam tests. The modules, similar to those used in the Endcaps of the CMS electromagnetic calorimeter (ECAL), were formed from 5×5 matrices of PbWO4 crystals, which had previously been exposed to 24 GeV protons up to integrated fluences between 2.1× 1013 and 1.3× 1014 cm−2. These correspond to the predicted charged-hadron fluences in the ECAL Endcaps at pseudorapidity η = 2.6 after about 500 fb−1 and 3000 fb−1 respectively, corresponding to the end of the LHC and High Luminosity LHC operation periods. The irradiated crystals have a lower light transmission for wavelengths corresponding to the scintillation light, and a correspondingly reduced light output. A comparison with four crystals irradiated in situ in CMS showed no significant rate dependence of hadron-induced damage. A degradation of the energy resolution and a non-linear response to electron showers are observed in damaged crystals. Direct measurements of the light output from the crystals show the amplitude decreasing and pulse becoming faster as the fluence increases. The latter is interpreted, through comparison with simulation, as a side-effect of the degradation in light transmission. The experimental results obtained can be used to estimate the long term performance of the CMS ECAL.

The CYGNO project aims at the development of a high precision optical readout gaseous Tima Projection Chamber (TPC) for directional dark matter (DM) searches, to be hosted at Laboratori Nazionali del Gran Sasso (LNGS). CYGNO employs a He:CF4 gas mixture at atmospheric pressure with a Gas Electron Multiplier (GEM) based amplification structure coupled to an optical readout comprised of sCMOS cameras and photomultiplier tubes (PMTs). This experimental setup allows to achieve 3D tracking and background rejection down to O(1) keV energy, to boost sensitivity to low WIMP masses. The characteristics of the optical readout approach in terms of the light yield will be illustrated along with the particle identification properties. The project timeline foresees, in the next 2–3 years, the realisation and installation of a 0.4 m3 TPC in the underground laboratories at LNGS to act as a demonstrator. Finally, the studies of the expected DM sensitivities of the CYGNO demonstrator will be presented.

Abstract We are going to discuss the R&D and the prospects for the CYGNO project, towards the development of an innovative, high precision 3D tracking Time Projection Chamber with optical readout using He:CF 4 gas at 1 bar. CYGNO uses a stack of triple thin GEMs for charge multiplication, this induces scintillation in CF 4 gas, which is readout by PMTs and sCMOS cameras. High granularity and low readout noise of sCMOS along with high sampling of PMT allows CYGNO to have 3D tracking with head tail capability and particle identification down to O(keV) energy for directional Dark Matter searches and solar neutrino spectroscopy. We will present the most recent R&D results from the CYGNO project, and in particular the overground commissioning of the largest prototype developed so far, LIME with a 33×33 cm 2 readout plane and 50 cm of drift length, for a total of 50 litres active volume. We will illustrate the LIME response characterisation between 3.7 keV and 44 keV by means of multiple X-ray sources, and the data Monte-Carlo comparison of simulated sCMOS images in this energy range. Furthermore, we will present current LIME installation, operation and data taking at underground Laboratori Nazionali del Gran Sasso (LNGS), serving as demonstrator for the development of a 0.4 m 3 CYGNO detector. We will conclude by mentioning the technical choices and the prospects of the 0.4 m 3 detector, as laid out in the Technical Design Report (TDR) recently produced by our collaboration.

Abstract The nature of dark matter is still unknown and an experimental program to look for dark matter particles in our Galaxy should extend its sensitivity to light particles in the GeV mass range and exploit the directional information of the DM particle motion (Vahsen et al. in CYGNUS: feasibility of a nuclear recoil observatory with directional sensitivity to dark matter and neutrinos, arXiv:2008.12587 , 2020). The Cygno project is studying a gaseous time projection chamber operated at atmospheric pressure with a Gas Electron Multiplier (Sauli in Nucl Instrum Meth A 386:531, https://doi.org/10.1016/S0168-9002(96)01172-2 , 1997) amplification and with an optical readout as a promising technology for light dark matter and directional searches. In this paper we describe the operation of a 50 l prototype named LIME (Long Imaging ModulE) in an overground location at Laboratori Nazionali di Frascati (LNF) of INFN. This prototype employs the technology under study for the 1 cubic meter Cygno demonstrator to be installed at the Laboratori Nazionali del Gran Sasso (LNGS) (Amaro et al. in Instruments 2022, 6(1), https://www.mdpi.com/2410-390X/6/1/6 , 2022). We report the characterization of LIME with photon sources in the energy range from few keV to several tens of keV to understand the performance of the energy reconstruction of the emitted electron. We achieved a low energy threshold of few keV and an energy resolution over the whole energy range of 10–20%, while operating the detector for several weeks continuously with very high operational efficiency. The energy spectrum of the reconstructed electrons is then reported and will be the basis to identify radio-contaminants of the LIME materials to be removed for future Cygno detectors.

Large granularity and high sensitivity commercial CMOS readout systems open the possibility of developing particle detectors with very interesting performance for different applications, from the search of rare and exotics events, such as dark matter directional candidates, to high quality neutron/ion/hadron beam monitor, mainly for medical applications. The gas scintillation mechanisms was exploited for starting an R&D on large TPC-based detector, equipped with a Triple GEM amplification stage optically readout. By this approach, a 7 l sensitive volume detector was built and tested. Space resolutions of 35μm on the GEM plane (X, Y) and 100μm on Z and energy measurements with a precision of about 25% were obtained. Analysis of the track shapes provides precious information allowing very good particle discrimination.

G. OrgantiniF. AmeliG. CavotoE. Di MarcoF. PiacentiniS. MorgantiE. PasqualucciA. PolimeniM. RescignoF. Safai TehraniG. SalméP. ViciniR. Faccini

Optical readout of Gas Electron Multipliers (GEM) provides very interesting performances and has been proposed for different applications in particle physics. In particular, thanks to its good efficiency in the keV energy range, it is being developed for low-energy and rare event studies, such as Dark Matter search. So far, the optical approach exploits the light produced during the avalanche processes in GEM channels. Further luminescence in the gas can be induced by electrons accelerated by a suitable electric field. The CYGNO collaboration studied this process with a combined use of a triple-GEM structure and a grid in an He/CF$_4$ (60/40) gas mixture at atmospheric pressure. Results reported in this paper allow to conclude that with an electric field of about 11~kV/cm a photon production mean free path of about 1.0~cm was found.

Abstract CYGNO is a project realising a cubic meter demonstrator to study the scalability of the performance of the optical approach for the readout of large-volume, GEM-equipped TPC. This is part of the CYGNUS proto-collaboration which aims at constructing a network of underground observatories for directional Dark Matter search. The combined use of high-granularity sCMOS and fast sensors for reading out the light produced in GEM channels during the multiplication processes was shown to allow on one hand to reconstruct 3D direction of the tracks, offering accurate energy measurements and sensitivity to the source directionality and, on the other hand, a high particle identification capability very useful to distinguish nuclear recoils. Results of the performed R&D and future steps toward a 30-100 cubic meter experiment will be presented.

An experimental study has been carried out on the fluidization of a Li/MgO catalyst under conditions typically used in the methane oxidative coupling process. The minimum fluidization velocity has been estimated in the 700–900°C temperature range and compared with the measured values. The effect of particle cohesion upon the minimum fluidization velocity has been studied, and the agglomeration has been related to the presence of a partially melted pool of carbonates on the catalyst surface.

The BaBar detector has operated over 200 2nd generation Resistive Plate Chambers (RPCs) in the forward endcap since 2002. Many chambers have increased noise rates and high-voltage currents. These aging symptoms are correlated with the integrated RPC current as expected, but also depend on the rate and direction of the gas flow, indicating that pollutants produced in the gas can accelerate aging of downstream RPC surfaces. HF produced by decomposition of the Freon 134a component of the BaBar RPC gas in electric discharges has been proposed as the main pollutant. This paper presents measurements of HF production and absorption rates in BaBar RPCs. Since many of the highest rate chambers in the forward endcap were converted to avalanche mode operation, a comparison of HF production in streamer and avalanche mode RPCs is made. Correlations between the HF production rate and other chamber operating conditions were also explored.

The MIP Timing Detector will provide additional timing capabilities for detection of minimum ionizing particles (MIPs) at CMS during the High Luminosity LHC era, improving event reconstruction and pileup rejection. The central portion of the detector, the Barrel Timing Layer (BTL), will be instrumented with LYSO:Ce crystals and Silicon Photomultipliers (SiPMs) providing a time resolution of about 30 ps at the beginning of operation, and degrading to 50-60 ps at the end of the detector lifetime as a result of radiation damage. In this work, we present the results obtained using a 120 GeV proton beam at the Fermilab Test Beam Facility to measure the time resolution of unirradiated sensors. A proof-of-concept of the sensor layout proposed for the barrel region of the MTD, consisting of elongated crystal bars with dimensions of about 3 x 3 x 57 mm$^3$ and with double-ended SiPM readout, is demonstrated. This design provides a robust time measurement independent of the impact point of the MIP along the crystal bar. We tested LYSO:Ce bars of different thickness (2, 3, 4 mm) with a geometry close to the reference design and coupled to SiPMs manufactured by Hamamatsu and Fondazione Bruno Kessler. The various aspects influencing the timing performance such as the crystal thickness, properties of the SiPMs (e.g. photon detection efficiency), and impact angle of the MIP are studied. A time resolution of about 28 ps is measured for MIPs crossing a 3 mm thick crystal bar, corresponding to an MPV energy deposition of 2.6 MeV, and of 22 ps for the 4.2 MeV MPV energy deposition expected in the BTL, matching the detector performance target for unirradiated devices.

The Time Projection method is an ideal candidate to track low energy release particles. Large volumes can be readout by means of a moderate number of channels providing a complete 3D reconstruction of the charged tracks within the sensitive volume. It allows the measurement not only of the total released energy but also of the energy release density along the tracks that can be very useful for particle identification and to solve the head-tail ambiguity of the tracks. Moreover, gas represents a very interesting target to study Dark Matter interactions. In gas, nuclear recoils can travel enough to give rise to tracks long enough to be acquired and reconstructed.

The Cygno project aims at the construction of a gaseous Time Projection Chamber (TPC) with optical readout for the high precision three-dimensional tracking of low energy nuclear and electronic recoils down to few keVs. The efficient discrimination between these two processes represents the main challenge of the modern dark matter direct detection experiments. In this context, the gaseous TPCs with optical readout are a promising and innovative technique that can reach very good energy and 3D position reconstruction capabilities thanks to the high performance of the latest generation of scientific CMOS (sCMOS) light sensors. The Cygno experimental setup is characterized by a TPC filled with a ${\rm He}$:${\rm CF_4}$ gas mixture at atmospheric pressure and equipped with a triple Gas Electron Multipliers (GEM) amplification stage. The visible light produced at the GEMs is collected by a scientific CMOS camera and by a set of fast photosensors. In this contribution we will present the 50 L prototype, called Long Imaging ModulE (LIME), foreseen to conclude the R\&D phase of the Cygno project. LIME has been recently installed underground at the Laboratori Nazionali del Gran Sasso (LNGS), with the aim of studying the performance of the Cygno experimental approach in a low background environment and developing a refined trigger and DAQ system for the future upgrades. This is a crucial step towards the development of a larger $\mathcal{O}(1 {\rm m^3})$ demonstrator, which will be an evolution of the LIME detector.

The R&D work of a gas detector for high precision particle tracking over large gas volumes is presented. The scintillation light accompanying the electronic avalanches in a triple GEM structure is detected by a CMOS-based camera. The sensor provides a high granularity along with low noise and a very high sensitivity (70% of quantum efficiency). Once operated with a large aperture and suitable focal length lens, large areas can be imaged at reduced costs. The performance of a prototype (called LEMOn), with a 7 litre sensitive volume, operated with a He/CF4 (60/40) mixture was studied on a 450 MeV electron beam and preliminary results are presented. A space resolution on the plane parallel to the GEM (X, Y ) of 90 μm was achieved in the whole sensitive volume. The effect of the electron diffusion on the drift was studied and exploited in order to evaluate the position in Z of the tracks. An innovative element is the concurrent readout of the light with a suitable photomultiplier system. It will complement the CMOS-readout by providing the time resolution necessary to the reconstruction of third coordinate of each cluster. By exploiting the time information, a resolution of 60 μm on Z was measured. Such a detector can be an interesting candidate for future large scale experiments searching for Dark Matter (DM) searches with directional sensitivity and for measurements of coherent neutrino scattering on nuclei. Additional applications of this detector might be in the realm of neutron detection, X-ray polarimetry and particle cancer therapy.

The CYGNO project aims at developing a high resolution Time Projection Chamber with optical readout for directional dark matter searches and solar neutrino spectroscopy. Peculiar CYGNO’s features are the 3D tracking capability provided by the combination of photomultipliers and scientific CMOS camera signals, combined with a helium-fluorine-based gas mixture at atmospheric pressure amplified by gas electron multipliers structures. In this paper, the performances achieved with CYGNO prototypes and the prospects for the upcoming underground installation at Laboratori Nazionali del Gran Sasso of a 50-L detector in fall 2021 will be discussed, together with the plans for a 1-m3 experiment. The synergy with the ERC consolidator, grant project INITIUM, aimed at realising negative ion drift operation within the CYGNO 3D optical approach, will be further illustrated.

The BaBar detector is currently operating nearly 200 Resistive Plate Chambers (RPCs), constructed as part of an upgrade of the forward endcap muon detector in 2002. Although the average RPC efficiency remains high, numerous changes in the RPC performance (increased currents and rates) have been observed. A few of the highest rate RPCs have suffered efficiency losses of more than 15%. Several types of efficiency loss have been observed. Tests with humidified gas have shown that some of the lost efficiency is recoverable. However, efficiency losses in the highest rate regions have not yet improved with humid gases.

Results are reported from a search for the effects of contact interactions using events with a high-mass, oppositely charged muon pair. The events are collected in proton-proton collisions at √s=7  TeV using the Compact Muon Solenoid detector at the Large Hadron Collider. The data sample corresponds to an integrated luminosity of 5.3  fb^(-1). The observed dimuon mass spectrum is consistent with that expected from the standard model. The data are interpreted in the context of a quark- and muon-compositeness model with a left-handed isoscalar current and an energy scale parameter Λ. The 95% confidence level lower limit on Λ is 9.5 TeV under the assumption of destructive interference between the standard model and contact-interaction amplitudes. For constructive interference, the limit is 13.1 TeV. These limits are comparable to the most stringent ones reported to date.

The CYGNO experiment aims at the development of a large gaseous TPC with GEM-based amplification and an optical readout by means of PMTs and scientific CMOS cameras for 3D tracking down to O(keV) energies, for the directional detection of rare events such as low mass Dark Matter and solar neutrino interactions. The largest prototype built so far towards the realization of the CYGNO experiment demonstrator is the 50 L active volume LIME, with 4 PMTs and a single sCMOS imaging a 33 × 33 cm2 area for 50 cm drift, that has been installed in underground Laboratori Nazionali del Gran Sasso in February 2022. We will illustrate LIME performances as evaluated overground in Laboratori Nazionali di Frascati by means of radioactive X-ray sources, and in particular the detector stability, energy response and energy resolution. We will discuss the MC simulation developed to reproduce the detector response and show the comparison with actual data. We will furthermore examine the background simulation worked out for LIME underground data taking and illustrate the foreseen expected measurement and results in terms of natural and materials intrinsic radioactivity characterization and measurement of the LNGS underground natural neutron flux. The results that will be obtained by underground LIME installation will be paramount in the optimization of the CYGNO demonstrator, since this is foreseen to be composed by multiple modules with the same LIME dimensions and characteristics.

The CYGNO experiment aims at the development of a large gaseous TPC with GEM-based amplification and an optical readout by means of PMTs and scientific CMOS cameras for 3D tracking down to O(keV) energies, for the directional detection of rare events such as low mass Dark Matter and solar neutrino interactions. The largest prototype built so far towards the realisation of the CYGNO experiment demonstrator is the 50 L active volume LIME, with 4 PMTs and a single sCMOS imaging a 33$\times$33 cm\textsuperscript{2} area for 50 cm drift, that has been installed in underground Laboratori Nazionali del Gran Sasso in February 2022. We will illustrate LIME performances as evaluated overground in Laboratori Nazionali di Frascati by means of radioactive X-ray sources, and in particular the detector stability, energy response and energy resolution. We will discuss the MC simulation developed to reproduce the detector response and show the comparison with actual data. We will furthermore examine the background simulation worked out for LIME underground data taking and illustrate the foreseen expected measurement and results in terms of natural and materials intrinsic radioactivity characterisation and measurement of the LNGS underground natural neutron flux. The results that will be obtained by underground LIME installation will be paramount in the optimisation of the CYGNO demonstrator, since this is foreseen to be composed by multiple modules with the same LIME dimensions and characteristics.

The CYGNO project for the development of a high precision optical readout gaseous TPC for directional Dark Matter search and solar neutrino spectroscopy will be presented. It is to be hosted at Laboratori Nazionali del Gran Sasso. CYGNO peculiar features are the use of sCMOS cameras and PMTs coupled to GEMs amplification of a helium-based gas mixture at atmospheric pressure, in order to achieve 3D tracking with head tail capability and background rejection down to O(keV) energy, to boost sensitivity to low WIMP masses. The latest R&D results within the CYGNO project will be discussed along with the underground installation and operation of a 50 l prototype, soon to be followed by a O(1) m3 experiment demonstrator in 2024-2026. The latest results on the negative ion drift operation at atmospheric pressure within CYGNO optical readout approach will be illustrated, which is the aim of the ERC Consolidator Grant project INITIUM.

Abstract The CYGNO experiment aims to study rare events related to the search for low-mass dark matter and solar neutrino events. One of the main components of background comes from cosmic rays that generate long tracks in the detector’s images. The interaction of such particles with the gas releases a variable energy profile along its trajectory to form tracks with multiple cores that can be easily reconstructed erroneously by being split into more than one cluster. Thus, this work offers a newly adapted version of the well-known density-based spatial clustering of applications with noise (DBSCAN) algorithm, called iDDBSCAN, which exploits the directional characteristics of the clusters found by the DBSCAN to improve its clustering efficiency when dealing with multi-core tracks. This paper provides a detailed explanation of this algorithm, covering its parameter validation and evaluating its influence when integrated into the experiment’s event selection routine. To generate background events, data acquisition was performed with the detector installed in an overground laboratory, leaving it exposed to natural radiation. To produce signals in the energy range of interest for the experiment, a 55 Fe radioactive source was used. The achieved results showed that the iDDBSCAN algorithm is capable of improving the background rejection of the experiment, through a more accurate reconstruction of the tracks produced by natural radiation such as cosmic rays, without deteriorating its signal detection efficiency and energy estimation.

Abstract Active Pixel sensors play a crucial role in enabling successful low-light scientific experiments due to their inherent advantages and capabilities. Such devices not only offer high spatial resolution but also feature individual pixels with integrated amplifiers, allowing for direct signal amplification at the pixel level. This results in reduced readout noise and improved signal-to-noise ratio (SNR), which are particularly vital when dealing with limited photon counts in low-light environments. This holds particularly true for scientific CMOS (sCMOS) sensors, acknowledged as an advanced evolution of Active Pixel sensors. However, despite their advantages, such sensors can still exhibit limitations such as higher cost and presence of noise artifacts that should be closely investigated. In particular, CYGNO project fits in a global effort aimed at direct detection of Dark Matter particles. CYGNO collaboration intends to build a detector based on a Time Projection Chamber making use of Gas Electron Multipliers for the amplification of ionization electrons. The GEM multiplication process produces photons that can be readout by a high-resolution sCMOS sensor. Such detection system is being designed to have enough sensitivity to detect low-energy particles and to measure released energy with enough granularity so to reconstruct direction and energy profile along their trajectories. The image sensor has an important role in the detector performance, having a direct impact on the SNR of the experiment. This work proposes a study on the performance of three different sCMOS sensors with respect to their sensitivity to low-energy particles and their intrinsic noise, which are of the utmost importance for various scientific experiments.

In this paper I will briefly introduce the idea of using Carbon Nanotubes (CNT) as target for the detection of low mass WIMPs with the additional information of directionality. I will also present the experimental efforts of developing a Time Projection Chamber with a CNT target inside and the results of a test beam at the Beam Test Facility of INFN-LNF.

The Time Projection method is ideal to track low kinetic energy charged particles, in particular for the study for Dark Matter interactions. With this technique we aim to readout large volumes with a moderate number of channels providing a complete 3D reconstruction of the tracks within the sensitive region. The total released energy and the energy density along the tracks can be both measured allowing for particle identification and to solve the head–tail ambiguity of the track. Moreover, in gas, nuclear recoils induced by a Dark Matter particle scattering can yield tracks long enough for its direction to be inferred. We describe here a prototype TPC with a GEM amplification stage. The readout is based on the detection of the light produced in the GEM with a high granularity sCMOS sensor in conjunction with a photomultiplier. The prototype was exposed to γ and neutron source and to minimum ionizing particles, obtaining very promising results in terms of detection efficiency, energy resolution and particle identification.

The design of the project named CYGNO is presented. CYGNO is a new proposal supported by INFN, the Italian National Institute for Nuclear Physics, within CYGNUs proto-collaboration (CYGNUS-TPC) that aims to realize a distributed observatory in underground laboratories for directional Dark Matter (DM) search and the identification of the coherent neutrino scattering (CNS) from the Sun. CYGNO is one of the first prototypes in the road map to 100-1000 m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> of CYGNUs and will be located at the National Laboratory of Gran Sasso (LNGS), in Italy, aiming to make significant advances in the technology of single phase gas-only time projection chambers (TPC) for the application to the detection of rare scattering events. In particular it will focus on a read-out technique based on Micro Pattern Gas Detector (MPGD) amplification of the ionization and on the visible light collection with a sub-mm position resolution sCMOS (scientific COMS) camera. This type of readout - in conjunction with a fast light detection - will allow on one hand to reconstruct 3D direction of the tracks, offering accurate sensitivity to the source directionality and, on the other hand, a high particle identification capability very useful to distinguish nuclear recoils.

The design of the project named CYGNO is presented. CYGNO is a new proposal supported by INFN, the Italian National Institute for Nuclear Physics, within CYGNUs proto-collaboration (CYGNUS-TPC) that aims to realize a distributed observatory in underground laboratories for directional Dark Matter (DM) search and the identification of the coherent neutrino scattering (CNS) from the Sun. CYGNO is one of the first prototypes in the road map to 100-1000 m^3 of CYGNUs and will be located at the National Laboratory of Gran Sasso (LNGS), in Italy, aiming to make significant advances in the technology of single phase gas-only time projection chambers (TPC) for the application to the detection of rare scattering events. In particular it will focus on a read-out technique based on Micro Pattern Gas Detector (MPGD) amplification of the ionization and on the visible light collection with a sub-mm position resolution sCMOS (scientific COMS) camera. This type of readout - in conjunction with a fast light detection - will allow on one hand to reconstruct 3D direction of the tracks, offering accurate sensitivity to the source directionality and, on the other hand, a high particle identification capability very useful to distinguish nuclear recoils.

The Time Projection Chamber (TPC) is an ideal candidate to track particles in a wide range of energies. Large volumes TPCs can be readout with a suitable number of channels offering a complete 3D reconstruction of the charged particle tracks and of their released energy allowing the identification of their mass. Moreover, He-based TPC's are very promising to study keV energy particles, opening the possibility for directional searches of Dark Matter (DM) and the study of Solar Neutrinos (SN). On the other hand, in order to reach a keV energy threshold, a large number of channels is required to obtain a high granularity, that could be expensive and hard to manage. A small prototype (named LEMOn) to test and validate an innovative read-out technique is described here. It based on the amplification of the ionization in Micro Pattern Gas Detector (MPGD) producing visible light collected by a sub-millimeter position resolution sCMOS (scientific CMOS) camera. This type of readout - in conjunction with a fast light detection - allows a 3D reconstruction of the tracks, a sensitivity to the track direction and a very promising particle identification capability useful to distinguish DM nuclear recoils from a gamma-induced background.

Studies of the Higgs boson spin and parity are presented using data samples corresponding to the γγ, ZZ, and WW decay channels. The analyses are based on pp collision data collected at centre-of-mass energies of 7 and 8 TeV, corresponding to integrated luminosities of approximately 5 fb-1 and 20 fb-1, respectively. The data are compared to the expectations for the standard model Higgs boson, and for several alternative models.

The CMS electromagnetic calorimeter (ECAL) comprises 75848 scintillating lead tungstate crystals. 61200 crystals are contained in the ECAL Barrel section and are read out by avalanche photodiode (APD) with internal gain of about 50. This gain is achieved with a high voltage (HV) of about 400 Volts. The gain stability requirement implies a supply voltage stable to within 0.01%. We describe our experience with the installed Barrel HV power supply system, which has been used for data taking since 2008.

The detector performance of the CMS electromagnetic calorimeter is monitored using applications based on the CMS Data Quality Monitoring (DQM) framework and running on the High-Level Trigger Farm as well as on local DAQ systems. The monitorable quantities are organized into hierarchical structures based on the physics content. The information produced is accessible by client applications according to their subscription requests. The client applications process the received quantities, according to pre-defined analyses, making the results immediately available, while also storing the results in a database, and in the form of static web pages, for subsequent studies. We describe here the functionalities of the CMS ECAL DQM applications and report about their use in real environments.

A full scale implementation of the Detector Control System (DCS) for the electromagnetic calorimeter (ECAL) in the Compact Muon Solenoid (CMS) experiment is presented. The operational experience from the ECAL commissioning at the CMS experimental cavern and from the first ECAL and global CMS data taking runs is discussed and summarized.

The aim of the CYGNO project is the construction and operation of a 1~m$^3$ gas TPC for directional dark matter searches and coherent neutrino scattering measurements, as a prototype toward the 100-1000~m$^3$ (0.15-1.5 tons) CYGNUS network of underground experiments. In such a TPC, electrons produced by dark-matter- or neutrino-induced nuclear recoils will drift toward and will be multiplied by a three-layer GEM structure, and the light produced in the avalanche processes will be readout by a sCMOS camera, providing a 2D image of the event with a resolution of a few hundred micrometers. Photomultipliers will also provide a simultaneous fast readout of the time profile of the light production, giving information about the third coordinate and hence allowing a 3D reconstruction of the event, from which the direction of the nuclear recoil and consequently the direction of the incoming particle can be inferred. Such a detailed reconstruction of the event topology will also allow a pure and efficient signal to background discrimination. These two features are the key to reach and overcome the solar neutrino background that will ultimately limit non-directional dark matter searches.

The observation of a new b baryon via its strong decay into Ξ_b^-π^+ (plus charge conjugates) is reported. The measurement uses a data sample of pp collisions at √s=7  TeV collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 5.3  fb^(-1). The known Ξb- baryon is reconstructed via the decay chain Ξ_b^-→J/ψΞ^-→μ^+μ^-Λ^0π^-, with Λ^0→pπ^-. A peak is observed in the distribution of the difference between the mass of the Ξ^b^-π^+ system and the sum of the masses of the Ξ_b^- and π^+, with a significance exceeding 5 standard deviations. The mass difference of the peak is 14.84±0.74(stat)±0.28(syst)  MeV. The new state most likely corresponds to the J^P=3/2^+ companion of the Ξ_b.

A search for the standard model Higgs boson decaying to W + W -. The pp collisions data sample corresponds to an integrated luminosity of 5.1 fb -1 at √ s = 7 TeV and 5.1 fb -1 at √ s = 8 TeV, collected by the CMS detector at the LHC.The W + W -candidates are selected in events in the fully leptonic or semi leptonic final state.Upper limits on the Higgs boson production relative to the standard model Higgs expectation are derived.The standard model Higgs boson is excluded in the mass range 129-520 GeV at 95% confidence level from the fully leptonic channel and in the mass ranges 260-460 GeV from the semi-leptonic channel.A 1.6 σ (2.4 σ ) excess of events is observed (expected) for low Higgs boson masses which makes the observed limits weaker than the expected ones under the null hypothesis.

SURF 2012. This project will be an experimental physics project to be developed at CERN, in collaboration with Caltechʼs CMS (Compact Muon Solenoid) group.

The analysis of vector-boson production in association to W → μν and Z → μμ with jets is presented using 5.0 fb−1 of data collected in 2012 by the CMS detector at the LHC with sqrt(s)=8 TeV

In this paper we give a description of the database services for the control and monitoring of the electromagnetic calorimeter of the CMS experiment at LHC. After a general description of the software infrastructure, we present the organization of the tables in the database, that has been designed in order to simplify the development of software interfaces. This feature is achieved including in the database the description of each relevant table. We also give some estimation about the final size and performance of the system.

We present the data quality monitoring of the CMS electromagnetic calorimeter, used as online analysis of the collected data and as prompt feedback on the status of the detector. This system has been developed and used during the commissioning of the detector. We also report the experience with the first long data taking of cosmic rays with CMS experiment fully operating in the underground cavern.

The Compact Muon Solenoid (CMS) is one of the general purpose particle detectors at the Large Hadron Collider (LHC) at CERN. The challenging constraints on the design of one of its sub-detectors, the Electromagnetic Calorimeter (ECAL), required the development of a complex Detector Control System (DCS). In this paper the general features of the CMS ECAL DCS during the period of commissioning and cosmic running will be presented. The feedback from the people involved was used for several upgrades of the system in order to achieve a robust, flexible and stable control system. A description of the newly implemented features for the CMS ECAL DCS subsystems will be given as well.

The detection of ultra-rare events as the interaction of galactic dark matter (DM) candidate particles or of neutrinos originated from the Sun requires the development of innovative detection techniques. In particular future experiments for direct DM detection requires to extend their sensitivity to masses well below 10 GeV. The Cygno collaboration plans to build and operate at the Laboratori Nazionali del Gran Sasso (LNGS) a cubic meter demonstrator of a gaseous time projection chamber (TPC), equipped with an optical readout and using a He:CF4 gas mixture kept at atmospheric pressure. The presence of low Z atoms allows to reach a competitive sensitivity to DM masses in the GeV range while the presence of fluorine can be used to set limits on a spin-dependent DM interaction cross-section. The Cygno TPC is equipped with a Gas Electron Multipliers (GEM) amplification stage of the primary ionization electrons. Light is produced from the GEM while scientific CMOS cameras and fast photodetectors are combined to obtaining a three-dimensional reconstruction of the tracks either due to nuclear or to electron recoils. The design and the sensitivity of the demonstrator based on advanced Monte Carlo simulations including the radioactivity of the materials and of the LNGS cavern are reported. Pattern recognition algorithms are used to evaluate the identification capability of nuclear recoils against electronic recoils and studied in data from small scale prototypes. Energy measurement and also sensitivity to the source directionality are also evaluated. A Cygno TPC would therefore be sensitive to the direction of electron recoils originated by solar neutrinos interactions. The Cygno collaboration plans to demonstrate the scalability of such detector concept to reach a target mass large enough to significantly extend our knowledge about DM nature and solar neutrinos.

Gaseous Time Projection Chambers (TPC) with optical readout are an innovative and very promising detection technique to enhance the the sensitivity for light dark matter candidates. The Cygno experiment is pursuing this technique by developing a TPC operated with gas mixtures at atmospheric pressure equipped with a Gas Electron Multipliers (GEM) amplification stage that produces visible light. Light is collected by a high sensitivity and resolution scientific CMOS camera, while a fast photodetector is used to measure the drift time of the primary ionization electrons and thus reconstruct the third coordinate of the ionization track. In this contribution, we illustrate the technical solutions developed to construct detector prototypes and discuss their performances when exposed to radioactive sources. We present results in terms of electro-luminescence yield and charge gain when operated with gas mixtures based on He:CF4 and He:CF4-isobutane, and different electric field configurations. We also discuss the solutions adopted for the DAQ and trigger systems and the performances of an innovative multi-stage pattern recognition algorithm based on advanced clustering techniques. We show how such solutions are essential to identify and select interesting events and how we plan to have them online to cope with the data throughput. Finally, we show the evolution of the project from small size detectors to the current 50 litres prototype which will be installed and tested underground at LNGS this year. A 1m3 demonstrator is expected to be built in 2021/22 and subsequently installed and commissioned at LNGS aiming at a large scale apparatus in a later stage.

Innovative experimental techniques are needed to further search for dark matter Weakly Interacting Massive Particles (WIMPs).The ultimate limit is represented by the ability to efficiently reconstruct and identify nuclear and electron recoil events at the experimental energy threshold.Gaseous Time Projection Chambers (TPC) with optical readout are very promising candidates thanks to the 3D event reconstruction capability of the TPC technique and the high sensitivity and granularity of last generation light sensors.The Cygno experiment is pursuing this technique by developing a TPC operated with He:CF 4 gas mixture at atmospheric pressure equipped with a Gas Electron Multipliers (GEM) amplification stage that produces visible light collected by a scientific CMOS camera.Events are then reconstructed with an innovative multi-stage pattern recognition algorithm based on advanced clustering techniques.In this contribution, we present the performances of several prototype detectors assessed by exposing them to radioactive sources.We show that good energy and spatial resolution as well as discriminating power between nuclear and electron recoils is achieved in the keV energy range.Finally, we discuss the plan to build a 1 m 3 demonstrator expected to be installed and operated at LNGS in 2023/24.This experimental campaign aims at proving the scalability of such a detector concept to a bigger apparatus able to significantly extend our knowledge about DM and neutrinos.

Innovative experimental techniques are needed to further search for dark matter weakly interacting massive particles. The ultimate limit is represented by the ability to efficiently reconstruct and identify nuclear and electronic recoil events at the experimental energy threshold. Gaseous Time Projection Chambers (TPC) with optical readout are very promising candidates thanks to the 3D event reconstruction capability of the TPC technique and the high sensitivity and granularity of last generation scientific light sensors. The CYGNO experiment is pursuing this technique by developing a TPC operated with He-CF$_4$ gas mixture at atmospheric pressure equipped with a Gas Electron Multipliers (GEM) amplification stage where visible light is produced. The combined use of high-granularity sCMOS cameras and fast light sensors allows the reconstruction of the 3D direction of the tracks, offering good energy resolution and very high sensitivity in the few keV energy range, together with a very good particle identification useful for distinguishing nuclear recoils from electronic recoils. We present the design and the sensitivity of a 50L prototipe which is currently being installed underground at LNGS and will be operated already in 2022. The performances of the prototype are evaluated with an advanced Monte Carlo simulation and by calibration runs with radioactive source. We show that good energy and spatial resolution as well as discriminating power between nuclear and electronic recoils is achieved in the keV energy range. The Cygno collaboration plans to demonstrate the scalability of such detector concepts to reach a target mass large enough to significantly extend our knowledge about DM nature and solar neutrinos.

The proposal of CYGNO experiments, is the construction of one cubic meter, single-phase, gas-only Time Projection Chambers (TPCs) for Directional Dark Matter search. The particularity of CYGNO is the read-out technique based on Micro Pattern Gas Detector (MPGD) amplification of the ionization and on the collection of the yielded visible light by a scientific CMOS camera with a sub-mm position resolution. Four PMTs, arranged on the four sides of the detector, work as the trigger and are used to calculate the third coordinate of the tracks, to identify the electron and the nuclear recoils. The center of gravity of PMTs enables us to quickly identify the position of the track on the camera pictures and speed up the online analysis. In this work, the time and spatial resolution of the system are studied on LIME-2, the new 50 liters prototype, using the same readout electronics of the CYGNO DAQ system.

In the Standard Model (SM) of particle physics, the phase of the Cabibbo-Kobayashi-Maskawa (CKM) quark-mixing matrix [1, 2] is the only source of CP violation in the quark sector. Due to the interference between mixing and decay, this phase can be observed in measurements of time-dependent CP asymmetries of B{sup 0} mesons. In the SM, CP asymmetries in b {yields} s{bar s}s decays, such as B{sup 0} {yields} K{sup +}K{sup -}K{sup 0}, are expected to be nearly equal to those observed in tree-dominated b {yields} {bar c}s decays [3]. However, because in the SM the former are dominated by loop amplitudes, new particles in those loops potentially introduce new physics at the same order as the SM process. Within the SM, deviations from the expected CP asymmetries in B{sup 0} {yields} K{sup +}K{sup -}K{sup 0} decays depend on the Dalitz plot position, but are expected to be small and positive [4]. In particular, for the decay B{sup 0} {yields} {phi}K{sup 0} they are expected to be less than 4%. BABAR extracts the time-dependent CP-violation parameters by taking into account different amplitudes and phases across the B{sup 0} and {bar B}{sup 0} Dalitz plots, while Belle measures it separately for B{supmore » 0} {yields} {phi}K{sup 0} and the rest of K{sup +}K{sup -}K{sup 0} events, neglecting interference between intermediate states. The analyses presented here are based on 347 (535) million B{bar B} pairs collected with the BABAR (Belle) detector at the SLAC PEP-II (KEKB) e{sup +}e{sup -} asymmetric-energy collider. Data are collected on the {Upsilon}(4S) resonance, while a fraction of about 10% is collected at approximately 40 MeV below the {Upsilon}(4S) resonance, and it is used to study the background arising from e{sup +}e{sup -} {yields} q{bar q} (q = u, d, s, c) continuum events. The BABAR and Belle detectors are described in detail elsewhere [5].« less

In this work we presented measurements of CP violation and decay rates of B decays in final states not involving a charm quark in the final state. In particular, the time-dependent CP asymmetries of decays which proceed through b → s elementary transition is a particularly sensitive probe of physics beyond the Standard Model. In fact, even if the precise measurements of CP conserving and CP violating processes show the success of the CKM picture of the flavour physics, the sector of b → s transitions is still not strongly constrained and leaves room for new physics contributions. In particular, we considered the decays which have the cleanest theoretical prediction within the Standard Model: B0 → ΦK0 and B0 → K$0\atop{s}$K$0\atop{s}$K$0\atop{s}$ β$eff\atop{SM}$ = 0.379. We examined the former with a completely new approach with respect to the past: the study of CP violation in the whole K+K-K0phase space through a time-dependent Dalitz plot analysis. With this approach, we simultaneously measured the CP-violating asymmetries of the ΦKJ0, f0(980)K0 resonant and K+K-K0 non-resonant contributions, avoiding one of the largest uncertainties which affected the previous measurements of B0 → ΦK0. We find β eff(B0 → ΦK0) = 0.06 ± 0.16 ± 0.05, which is lower than the Standard Model expectation, but it is consistent with it within two standard deviations. Moreover, only a recently developed experimental technique, which allows the determination of the position of B decay vertex when no charged tracks are originating from it, has made possible the measurement of the time-dependent CP asymmetry in B0 → K$0\atop{s}$K$0\atop{s}$K$0\atop{s}$ decays. The mixing-induced CP parameter S in the Standard Model should be equal to sin 2β parameter, which is measured with high precision in B → [c$\bar{c}$]K0 decays by the B-factories. This statement is true, in the Standard Model, with excellent approximation for the decays studied in this work. The summary of the measurements in the b → s sector is shown in Fig. 9.8 A naive average of the b → s penguins, which does not account for the correlations existing among ΦK0, f0(980)K0 and K+K-K0, and that includes also modes with larger theoretical uncertainties, shows that -ηCP x S is lower than sin 2β. This is not an evidence of physics beyond the Standard Model, but the systematic deviation from the expected value is an hint that there is room for it. More compelling evidence for new physics could be obtained measuring significant deviation in each decay channel from Standard Model prediction. Currently all the measurement are statistically limited and therefore an increase in accumulated statistics will shed more light into this quest for New Physics.

The Time Projection method is an ideal candidate to track low energy release particles. Large volumes can be readout by means of a moderate number of channels providing a complete 3D reconstruction of the charged tracks within the sensitive volume. It allows the measurement not only of the total released energy but also of the energy release density along the tracks that can be very useful for particle identification and to solve the head-tail ambiguity of the tracks. Moreover, gas represents a very interesting target to study Dark Matter interactions. In gas, nuclear recoils can travel enough to give rise to tracks long enough to be acquired and reconstructed.

Several electroweak precision measurements are performed by the ATLAS and CMS collaborations at the LHC. The main ones are carried out using Drell-Yan production of single W and Z boson. They regard the measurement of the production cross sections of W and Z bosons, the mass of the W boson, and $\sin^2θ_W$. The results of the $\sin^2θ_W$ measurements have an accuracy of approximately twice that reached at LEP and SLD. Other measurements reported are about the Drell-Yan differential production cross section.

We present recent results on CP violation, and the determination of CKM angle beta, with the decay B0->K+K-K0, with BABAR and Belle detectors.

This work proposes to evaluate the effect of digital filters when applied to images acquired by the ORANGE prototype of the Cygno experiment. A preliminary analysis is presented in order to understand if filtering techniques can produce results that justify investing efforts in the pre-processing stage of those images. Such images come from a camera sensor based on CMOS technology installed in an appropriate gas detector. To perform the proposed work, a simulation environment was created and used to evaluate some of the classical filtering techniques known in the literature. The results showed that the signal-to-noise ratio of the images can be considerably improved, which may help in subsequent processing steps such as clustering and particles identification.

Abstract The goal of the CYGNO project is to deploy at Laboratori Nazionali del Gran Sasso (LNGS) an high resolution Time Projection Chamber (TPC) with Gas Electron Multipliers (GEMs) amplification and optical 3D readout of an Helium/Fluorine based gas mixture for directional Dark Matter (DM) searches at low 1-10 GeV WIMP masses. The determination of the incoming direction of WIMP particles can in fact offer not only additional handles for discrimination of the annoying backgrounds, but especially an unique key for a positive, unambiguous identification of a DM signal.

Modern imaging sensors can be used to detect the scintillation light produced in Micro Pattern Gaseous Detectors (MPGDs) during electron avalanche multiplication. Gas mixtures with scintillation light spectra compatible with the quantum efficiency of CCD or CMOS cameras, can be used to implement an optical readout and to build 2D images of the events. Cygno project aims at developing an optical Time Projection Chamber (TPC) for directional dark matter searches and neutrino scattering measurements. A triple GEM stack is used as amplification stage, with the light produced during the multiplication process being detected by a sCMOS camera. The TPC is operated with a mixture of Helium (He) and Tetrafluoromethane (CF4). Recently many freon gases, as the CF4, have been banned due to their high impact on the atmosphere. Our group has started a study to use eco-friendly gases to replace the CF4 in such applications. The setup used to collect data and preliminary results in terms of charge gain and scintillation yield will be presented for some of the more interesting ecological gas mixtures available.

CYGNO experiment is working at the construction of one cubic meter TPC, based on Optical Readout of Gas Electron Multipliers (GEMs), for Directional Dark Matter search. This kind of research demands for very long dataacquisition runs and thus for high operation stability and reliability. This is one of the key elements of INITIUM project (ERC-2018-COG). The performance of such an approach was studied with a 7 liter sensitive volume detector. The detector was kept operative for 10 days in the working conditions able to provide full detection efficiency while continuously monitoring voltages and currents. Even if a few times per day the current drawn by the detector started to increase, these events could be recovered by an automated high voltage cycle. Dead time introduced by these procedures was evaluated to be lesser than 6% and the operation of the detector did not show any deterioration during the 10 days of the test.

Abstract The performances of an optical readout of Time Projection Chambers (TPCs) with multiple Gas Electron Multipliers (GEMs) amplification stages are presented. The detector is characterized by using 55 Fe photons converting inside a 7 litre sensitive volume detector in different electric field configurations. This prototype is developed as part of the R&amp;D for the CYGNO project for an application to direct Dark Matter search by detection of tracks of nuclear recoils in the gas within the keV energy range.

In this paper I will briefly introduce the idea of using Carbon Nanotubes (CNT) as target for the detection of low mass WIMPs with the additional information of directionality. I will also present the experimental efforts of developing a Time Projection Chamber with a CNT target inside and the results of a test beam at the Beam Test Facility of INFN-LNF.

We present recent results on CP violation, and the determination of CKM angle beta, with the decay B0-&gt;K+K-K0, with BABAR and Belle detectors.

We present recent results on time integrated and time dependent CP violation for charmless hadronic B decays using BABAR detector at the PEP-II B-factory.

We present recent results on time integrated and time dependent CP violation for charmless hadronic B decays using BABAR detector at the PEP-II B-factory.

We present recent results on time integrated and time dependent CP violation for charmless hadronic B decays using BABAR detector at the PEP-II B-factory.

The proposed CYGNO experiment is a one cubic meter, single-phase, gas-only Time Projection Chambers (TPCs) for Directional Dark Matter search. The particularity of CYGNO is the read-out technique based on Micro Pattern Gas Detector (MPGD) amplification of the ionization and on the collection of the yielded visible light by a scientific CMOS camera with a sub-mm position resolution. A corresponding fast light detection, through PMT or SiPM devices, allows reconstructing of the three-dimensional direction of the tracks enabling to distinguish the electron and nuclear recoils. The time performance of the photodetector and the time resolution of the acquisition system directly affects the capability in reconstructing the inclination of tracks. The performance of the different solutions is studied to guide the choice for the final application. The best PMT and SiPM, among those examined, are installed on LIME, a 50 litres CYGNO prototype. Optical signals and fast electrical signals of this detector are studied in this work