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We are happy to announce the 60th edition of the International Winter Meeting on Nuclear Physics.
This long-standing conference is dedicated to bringing together researchers and students from various fields of subatomic physics, such as
The conference location is Bormio, a beautiful mountain resort in the Italian Alps.
For further information, please also visit the Bormio conference website.
Pre-conference school:
To improve the participation of students and young researchers at the conference, a pre-conference school is taking place on SUNDAY, 21 January 2024: There will be topical lectures covering the basis of the main physics topics dealt with in the conference. Students are asked to select the proper field in the registration form, if they intend to participate.
The four fundamental interactions and their symmetries, the fundamental constants as well as the properties of elementary particles like masses and moments, determine the basic structure of the universe and are the basis for our so well tested Standard Model (SM) of physics. Performing stringent tests on these interactions and symmetries in extreme conditions at lowest energies and with highest precision will allow us to search for physics beyond the SM. Any improvement of these tests beyond their present limits requires novel experimental techniques. An overview is given on recent mass and g-factor measurements with extreme precision on single or few cooled ions stored in Penning traps. Among others the most stringent test of bound-state quantum electrodynamics could be performed. Here, the development of a novel technique, based upon the coupling of two ions as an ion crystal, enabled the most precise determination of a g-factor difference to date. This difference, determined for the isotopes 20,22Ne9+ with a relative precision of 5.6 × 10−13 with respect to the g factor, improved the precision for isotopic shifts of g factors by about two orders of magnitude. Our latest results on precision measurements with exotic ions in Penning traps will be presented.
Nucleons are the most fundamental bound three-body systems in Nature. Higgs boson couplings into QCD produce only a very small part of a baryon's mass and play little role in determining its structure. During the last decade crucial progress has been achieved in the exploration of the spectrum and the structure of nucleon resonances. Studies of exclusive πN, π+π−p, KΛ, and KΣ electroproduction off protons on the evolution of the electrocouplings with photon virtuality Q2 using the CLAS spectrometer have revealed a complex interplay between an inner core of three dressed quarks surrounded by an external meson-baryon cloud. CLAS12 is extending these results into an unexplored Q2 range, spanning the domain of quark momenta where ≈ 50% of hadron mass is generated. In the future, the increase of the CEBAF energy and the upgrade of the CLAS12 spectrometer to study exclusive electroproduction channels at higher luminosities and photon virtualities will offer a unique opportunity to explore how the dominant part of hadron mass and the bound three-quark structure of the resonant states emerge from QCD.
Strange particle production and propagation is sensitive to the properties of the surrounding matter and thus a tool to study the equation-of-state and the phase structure of QCD matter. Recent results from the beam energy scan II of STAR will be summarized and put into perspective with the anticipated performance of CBM at FAIR. For performance verification, Lambda production at SIS18 with mCBM will be discussed.
The Neutron Skin (NS), which is a phenomenon of an increased neutron to proton density ratio in the periphery of neutron-rich nuclei, is a prominent probe of the nuclear equation of state, connecting nuclear physics and astrophysics. However, the theoretical predictions and experimental measurements of the NS in $^{208}$Pb have been contradictory. The PREX-II experiment resulted in a much higher value of NS thickness in $^{208}$Pb than previous experiments. Furthermore, it does not match theoretical predictions when considered simultaneously with the similar CREX $^{48}$Ca measurement. In this work, we present the results of Monte-Carlo simulations of the Mainz Radius EXperiment (MREX), which aims to benchmark the PREX-II result using the detector set-up of the P2 experiment at the forthcoming Mainz Energy-recovering Superconducting Accelerator (MESA). We explore the experimental set-up options and calculate the measuring time to match or double the PREX-II precision. These results confirm the feasibility of the $^{208}$Pb NS thickness measurement at MREX.
The ALICE Inner Tracking System (ITS2) will be upgraded for LHC Run 4. The upgrade project foresees the replacement of the three innermost layers of the ITS2 with a truly cylindrical vertex detector, the ITS3. This innovative tracker will be composed of three self-supporting layers, each comprising two large-area (O(10×26 cm2)), ultra-thin (20 – 40 µm) and flexible stitched Monolithic Active Pixel silicon Sensors (MAPS). Such MAPS detectors will be fabricated with the 65 nm CMOS imaging process. Multiple test structures were included in the first test production run Multiple Layer Reticle 1 to validate the process. A wide campaign of laboratory and in-beam measurements is ongoing to characterize the prototypes. An excellent performance in terms of detection efficiency (> 99%), spatial resolution (4-5 µm) and response to X-rays was achieved, also for test structures irradiated up to 1×1013 1 MeV neq cm-2 (NIEL) and 10 kGy (TID), thus demonstrating the radiation hardness of the 65 nm CMOS process up to the expected level for the ALICE ITS3 operating environment. The first large-area sensors realized with the stitching technique in the 65 nm CMOS imaging process were included in the second production run Engineering Run 1 and are now under test. In addition to the development and validation of the sensor technology, an extensive R&D is ongoing to validate the functionalities of bent MAPS, for the realization of the ultra-light support structure in carbon foam and for the air-cooling system. This contribution aims to provide an up-to-date overview of the most recent R&D achievements for the ITS3.
ATOMKI Collaboration (Debrecen) observed anomalies in the angular distribution of e+e− pairs emitted via Internal pair Conversion (IPC) during nuclear de-excitation of the 8Be, 4He, and 12C. This enhancements seem to be compatible with the production, and successive decay, of a new vector boson with a mass of ∼ 17 MeV. PADME Collaboration performed an invariant mass scan in the sensible region where the new particle is expected to be during the RUN-3 completed at the end of 2022. The collaboration aims to search for X17 studiyng the resonant production, stimulated by the interaction of a positron beam impinging on electrons of a fixed target: e+e− → X17 → e+e−. Starting from the study of background processes due to the known interactions of the Standard Model, the sensitivity to the production of X17 was evaluated. These studies allowed tuning procedures for the data collection carried out in the second half of 2022. If PADME does not observe any signal, this will still allow setting stringent limits on the coupling of X17 with electrons.
In students' conference I want to introduce the discussion on the HEP's yet unsolved problem of possible CPT violation and baryon asymmetry of the universe (BAU), on which I was trying to work with Associate Prof. Merab Gogberashvili for my Bachelor's degree. After Anderson's discovery of the positron, the problem was obvious: for some unknown reasons the observable universe is matter dominated. In the expanding universe without some disturbances in baryon-antibaryon ratio soon after the Big Bang, both matter and antimatter would have been annihilated and I would not have been typing this. One of the several competing models is baryogenesis, which requires the fulfillment of Sakharov's conditions, but we do not have relevant results in the Standard Model. Another way to explain the observed value of BAU is matter-antimatter mass difference in the early universe, which is accompanied to possible CPT violation and it can happen in FRW spaces. Therefore, the key may lie in the strong gravitational fields at the early stages of the Universe expansion. Alternatively, the fact that CP violation treats particles and antiparticles unequally may be responsible for the mentioned dominance.
The method of moments has been employed to derive relativistic fluid-dynamical theories from the Boltzmann equation for the past decades [1]. This approach consists in expanding the single-particle distribution function using a basis of irreducible momenta, where the expansion coefficients are the irreducible moments of the nonequilibrium distribution function [2]. Unlike the Chapman-Enskog method [3], it has the advantage of yielding formulations that might be causal and stable, provided the transport coefficients satisfy certain constraints [4]. However, so far, only the equations of motion for the hydrodynamic moments have been explicitly calculated, with the equations of motion for the moments of rank 3 and 4 being calculated recently, in Ref. [5]. In this work, we address this problem by systematically calculating the general equations of motion for all irreducible moments and show how they can be used to solve the Boltzmann equation itself. Since this method of solving the Boltzmann equation does not rely on solving particle degrees of freedom, it can be used to provide a more consistent description of the freezeout process that does not require a particlization procedure. This prescription is investigated in a Bjorken flow scenario, where we investigate the transition from a fluid description to a transport one.
References:
[1] W. Israel and J. Stewart, Phys. Lett. A 58, 213 (1976).
[2] G. S. Denicol, H. Niemi, E. Molnár, and D. H. Rischke, Phys. Rev. D 85, 114047 (2012).
[3] S. Chapman and T. G. Cowling, The mathematical theory of non-uniform gases (Cambridge University Press, Cambridge, 1970).
[4] W. A. Hiscock and L. Lindblom, Ann. Phys. 151, 466 (1983); T. S. Olson, Ann. Phys. 199, 18 (1990); G. S. Denicol, T. Kodama, T. Koide, and P. Mota, J Phys. G 35, 115102 (2008); S. Pu, T. Koide, and D. H. Rischke, Phys. Rev. D 81, 114039 (2010); C. V. Brito and G. S. Denicol, Phys. Rev. D 102, 116009 (2020); J. Sammet, M. Mayer, and D. H. Rischke, Phys. Rev. D 107, 114028 (2023).
[5] C. V. P. de Brito and G. S. Denicol, Phys. Rev. D 108, 096020 (2023).
The nucleon–nucleon interaction may lead to the creation of clusters, mainly α-particles, inside the nuclear medium. The investigation of nuclear clustering has been a long-standing area of study and different experiments have been conducted with a variety of α-conjugated nuclei, mainly at the Coulomb barrier and Fermi energy range (1-100 MeV). The FOOT experiment aims to investigate the occurrence of the alpha-clustering phenomena at intermediate energies, by measuring the fragmentation of 12C and 16O with energies typical of hadrontherapy (200-400 MeV/u), exploiting the formation of intermediate channels in the production of α particles (e.g.: 12C->8Be+α->3α). At this energy range, the clustering phenomena can have a impact on the multiplicity and energy distribution of nucleons and light fragments, leading to correction on the evaluation of the Relative Biological Effectiveness (RBE) value adopted in clinical applications. FOOT consists of two different setups for the detection of heavy (Z≥3) and light (Z≤3) fragments: the former are detected by a high precision tracking system in magnetic field, a time of flight measurement system and a calorimeter, while the latter are measured by a separated emulsion cloud chamber detector. The methods and the expected results about the capability of the FOOT experiment to evaluate alpha-clustering phenomena in the fragmentation of 12C and 16O ion beams at 200 and 400 MeV/u will be presented.
The ALICE experiment at CERN is in the process of upgrading its Inner Tracking System (ITS). This upgrade (ITS3), involves replacing the innermost tracking layers with wafer scale cylindrically bent MAPS (Monolithic Active Pixel Sensors) chips. The inner layers will be positioned closer to the collision points while significantly reducing the material budget, which will notably enhance the vertexing resolution. The use of bent silicon detectors at this scale is a novel endeavor, and extensive research and development (R&D) efforts are underway to address the challenges associated with this unique geometry. Initial performance testing involves the bending of thinned ALPIDE chips, the MAPS devices employed in the existing ITS detector. A miniature telescope, denoted as μITS3, featuring five ALPIDEs bent at the same radii planned for the final detector, underwent testing using a proton beam directed at a plastic fiber target at the Bronowice Cyclotron Center in Krakow. Due to the relatively low beam energies of 80, 120, and 200 MeV this test-beam campaign enables to study the signature of protons with very high energy loss in the silicon. With this, the proton signal could be separated from the background delta electrons by comparing the obtained cluster size of each hit. Moreover, the observed cluster size aligned with the expected energy loss for protons at various energy levels. Additionally, an extensive investigation of alignment strategies, including novel approaches using machine learning, was carried out. Aligning bent detectors presents inherent challenges compared to flat detectors due to the additional degrees of freedom arising from the cylindrical shape. The aligned detector achieved a vertexing resolution of approximately 50 μm, approaching the lower limit set by multiple scattering effects.
A compilation of the experimental p+p data of neutral and charged kaon production has revealed a discrepancy between the observed K0 s yield and the the average number of produced charged kaons K0 s = (K+ +K−)/2. This widespread relation holds only for a colliding system that is an uniform population w.r. to the isospin (i.e. that consists of an equal number of all members of a given isospin multiplet). This is not the case for p+p collisions therefore one should not expect that it will describe the data accurately. A much better agreement is obtained with a model based on the quark structure of the participating hadrons (see Eur.Phys.J.C 83 (2023) 10, 928). Predictions of this model for p-A (see Eur.Phys.J.C 76 (2016) 2, 84) and A-A will also be presented.
R&D efforts are ongoing to develop a cylindrical Micromegas tracker for the central barrel of the ePIC detector, the first experiment at the future Electron Ion Collider (EIC). The Micromegas detectors will be a part of a multi-technology tracker that needs to fit inside a 1.7 T solenoid, bringing stringent constraints on space, material budget and number of electronic channels. As such, a light resistive Micromegas equipped with a 2D readout is required. The R&D focuses on the optimization of the readout system, which is made of a resistive layer read through capacitive effect by a pattern of readout electrodes. The goal is to minimize the number of readout channels while keeping a good spatial resolution. A beam test with different prototypes has been conducted at the MAMI electron beam, of which preliminary results will be presented.
The Belle-II experiment with its e+e− collisions allow observations of exotic states, complementa- ry to those in heavy-ion collisions as for example at LHCb. The Belle-II detector is commissioned at the SuperKEKB B-Factory in Japan and provides vital conditions for the study of such states. A bound state with six quarks and uuddss-content has strangeness quantum-number (−2) and would be the lightest six-quark state. Prime candidates for this composition are the H-Dibaryon and the Sexaquark ‘S‘. Theoreticians have predicted them for decades, but no experiment to date could demonstrate their existence. A neutral spin-0 state with six quark above 2.05 GeV and below 2.23 GeV, would decay via the weak-interaction into Λpπ−, which is what recent QCD-calculations point towards. In contrast to that, a uuddss-state mass below 2.05 GeV would be light enough to be stable. The S would not couple to pions and be much more compact than usual baryons. The increase in luminosity targeted by Belle-II will help further constrain the upper limits on these channels, which is the main goal of this analysis. The reconstruction of H → [Λ → pπ] pπ− and its selection using Machine-Learning techniques will be described and its performance discussed. Since both six- quark state candidates include Λs in the decay-channel, they are of major interest. Furthermore, an overview of the detector setup will be given.
Using data collected in pp collisions at √s = 13 TeV with the ALICE detector during the Run 2 period of the LHC, the femtoscopy technique has been successfully employed to extend the boundaries of known hadron-hadron interactions into the S = -3 sector and to initiate studies of charmed and three-body systems. The key element of these analyzes is the assumption of a common particle emitting source whose size scales with the average transverse mass (mT) of the pair. This assumption has been confirmed in high multiplicity pp collisions, particularly with p–p and p–Λ pairs. It was shown that both pairs are emitted from a source with the same core radius, which is increased to an effective source radius by the decay of short-lived resonances feeding into the pair yield. The Run 3 data-taking period of the LHC, which started in the summer of 2022, will significantly boost the amount of data due to the upgraded ALICE detector and the dedicated triggers. This will allow to advance the precision studies of hadron-hadron interactions even further. For that, a precise control over the particle emitting source is necessary, which can be achieved with a more differential measurement of the mT scaling. In 2022 alone the ALICE experiment collected the largest minimum bias dataset in its history, consisting of roughly 600 Billion events. This provides for the first time the opportunity to study differentially the mT scaling as a function of multiplicity. In this contribution we present preliminary results of the effective source sizes of p–p pairs differentially in multiplicity and mT, which were obtained by analysing all the available MB pp data from the 2022.
Elastically scattered electrons polarised perpendicular to the scattering plane will exhibit a count rate asymmetry (A$_{n}$) amongst left and right, which can be used as a probe for multi photon exchange contributions to the scattering amplitude. While for most target nuclei A$_{n}$ is in good agreement with the theoretical predictions, previuos measurements on $^{208}$Pb obtained values incompatible with existing theories, making it the most interresting target nucleus. However, lead as target material poses several experimental challenges, ranging from its low melting point and limited scattering rate to high background radiation interfering with the experimental set-up. A unique set-up for the measurement of A$_{n}$ at the A1-Collaboration at the Mainz-Microtron was developed, which aims to minimize analog disturbances by digitizing the measured signals as close to their origin as possible.
Linear stability of Israel-Stewart theory in the presence of net-charge diffusion was investigated in [C. V. Brito and G. S. Denicol, Linear stability of Israel-Stewart theory in the presence of net-charge diffusion, Phys. Rev. D 102, 116009 (2020)] for the case of a massless, classical gas of noninteracting particles. However, in that work only a vanishing net-charge background was considered. In this work, we extend that study to the case of a nonvanishing background charge. We find that this effectively results in a change of the numeric value of the charge-diffusion coefficient, in a way that when the background charge goes to infinity, this coefficient can become at most four times its value at zero background charge. We also extend the analysis of Brito and Denicol [Linear stability of Israel-Stewart theory in the presence of net-charge diffusion, Phys. Rev. D 102, 116009 (2020)] by performing a systematic parameter study in the plane of charge-diffusion coefficient vs the coupling term between shear-stress and net-charge diffusion. In this plane, we identify regions where the solutions remain stable and causal and where they become acausal and/or unstable.
From the deuteron to hyper-hydrogen 4, produced in nuclear collisions at RHIC and LHC, lessons from the QCD phase boundary
More than 50 years after the discovery of neutrons stars, their interior composition and structure remains unknown. Because the extreme densities and matter asymmetry in neutron star interiors are out of reach for Earth laboratories, the equation of state of bulk nuclear matter is unknown, with important implication for astrophysics and nuclear physics. Thankfully, measurements of neutron stars masses and radii are direct probes of the interior of these compact objects. In the past two decades, X-ray observatories have provided some measurements of neutron star radii and therefore some constraints on the dense matter equation of state. Recently, the results from the NICER Observatory resulted in the most promising, robust and precise results. I will review some of the key results from the NICER mission, give an overview of other existing measurements of masses and radii, and provide an overview of expected constraints from future observatories.
Results from B factories, the LHC and Fermilab suggest that flavor physics could be an alternate path to breaking the Standard Model of particle physics. I review some of the possibilities for Beyond the Standard Model (BSM) discoveries at Belle II and a few relevant recent results including the first evidence for the missing energy "penguin" decay B->K nu nubar reported at EPS Hamburg in August, 2023. Three new possibilities for finding BSM physics will be outlined: two of these involve angular correlations in B->D l nu and B->K l+ l- while the third is B->K(*) nu nubar decays.
The proton radius puzzle began in 2010 when the CREMA Collaboration released their measurement of the proton radius (Pohl et. al (2010)) from muonic hydrogen spectroscopy: rp=0.84184(67) fm, This was five standard deviations smaller that the accepted CODATA value at that time (0.8768(69) fm), and sparked an enduring and intriguing puzzle. This puzzle has been addressed in repeated electron scattering measurements seeking to go lower in Q2, such as PRad at Jefferson Lab, and the Mainz Initial State Radiation experiment. There has also been a plethora of new atomic hydrogen spectroscopy experiments, and some more muonic atom spectroscopy. The results of these measurements have served to further add to the puzzle, with even CODATA saying that more and different measurements are needed. This talk will provide an overview of the current status of the puzzle and touch upon current and planned scattering experiments, with a focus on MUSE, the Muon proton Scattering Experiment.
The IceCube Observatory, that instruments a cubic-kilometer of the South Pole ice, records neutrinos from various sources and over a broad range of energies. These events can be used to gain insight into astrophysical phenomena as well as into the fundamental properties of the neutrino itself. In this talk, I will give an overview over some recent scientific highlights, including the observation of neutrino emission from the galactic plane, and measurements of oscillation properties of the neutrino.
The Beijing Spectrometer (BESIII) at the Beijing Electron-Positron Collider (BEPC-II) is a multi-purpose hadron physics experiment optimized in the tau-charm energy region. Its world-record samples of vector charmonia such as J/Psi, Psi(3686) and Psi(3773), as well as energy scans between 2.0 GeV and 4.95 GeV have opened new avenues in hadron spectroscopy and structure. Furthermore, recently developed experimental techniques combined with the abundant production of strange hyperon-antihyperon pairs have enabled unique tests of fundamental symmetries as well as novel probes of hyperon-nucleon and antihyperon-nucleon interactions. In this talk, I will present recent highlights from the BESIII experiment, with the ambition to reflect its broad and diverse physics potential.
We study the impact of recent findings regarding non-perturbative corrections in the three-jet region to e+ e− hadronic observables, by performing a simultaneous fit of the strong coupling constant alpha_s and the non-perturbative parameter alpha_0 . We extend the calculation of these power corrections, already known for thrust and C-parameter, to other e+ e− hadronic observables. We find that for some observables the non-perturbative corrections are reasonably well behaved in the two-jet limit, while for others they have a more problematic behaviour. If one limits the fit to the three-jet region and to the well-behaved observables, one finds in general very good results, with the extracted value of alpha_s agreeing well with the world average. This is the case in particular for the thrust and C-parameter for which notably small values of alpha_s have been reported when non-perturbative corrections have been computed using analytic methods. Furthermore, the more problematic variables are also well described provided one stays far enough from the two-jet limit, while in this same region they cannot be described using the traditional implementation of power-corrections based on two-jet kinematics.
We summarise recent theoretical results on the QCD phase diagram and the properties of hadrons at finite temperature and chemical potential based on a combination of lattice QCD and Dyson-Schwinger equations. We discuss the location of the critical end point, the quality of extrapolations from imaginary to real chemical potential and the silver blaze property of mesons with different quantum numbers along the zero-T-finite-mu-axis. We furthermore investigate the influence of mesonic long range fluctuations on the order of the phase transition in the limit of vanishing up/down quark masses, varying the strange quark mass from zero to infinity. We find a second order phase transition for the whole left hand boundary of the Columbia plot in contrast to expectations based on the Pisarski/Wilczek
In the last years, several exotic states were observed in the charm sector; such particles cannot be interpreted as regular baryons or mesons and are thought to be either quark bags or molecular states. To unveil their nature, it is crucial to experimentally constrain the strong force that governs the interaction between the charm hadrons and other hadrons, for instance, via the measurement of the scattering parameters. The knowledge of the strong interaction in the charm sector is essential also for the study of ultrarelativistic heavy–ion collisions. In fact, during the hadronic phase of the system expansion, the charm hadrons can interact with the other particles produced in the collision, mainly light-flavor hadrons, via elastic and inelastic processes. These interactions modify the heavy-ion observables, and, to disentangle this effect from the signatures of the quark-gluon plasma formation, the scattering parameters of the charm hadrons with light-flavor hadrons are required. Despite the importance of constraining the charm-hadron interactions, the available experimental knowledge is very poor: so far, only the D-proton system was investigated, by using the femtoscopy technique in small systems at the LHC. In this contribution, these studies are extended, focusing on the open-charm and light-flavor meson systems. The measurement of the final-state strong interaction is performed using high-multiplicity pp collisions at sqrt(s) = 13 TeV collected by the ALICE Collaboration, and, employing the femtoscopy method, the scattering parameters of D± and D*± mesons with charged pions and kaons are extracted for the first time.
Core-collapse supernovae are the spectacular deaths of massive stars. These cosmic explosions are the birthplace of neutron stars and black holes. They synthesize many elements and emit copious amounts of neutrinos. One of the key ingredients in modeling core-collapse supernovae is the nuclear equation of state (EOS). The EOS affects many aspects of core-collapse supernovae, such as the explosion properties, the compact remnant, the neutrino emission from the nascent neutron star, and the composition of the innermost ejecta. In this talk, I will discuss recent results from over 1500 core-collapse supernova simulations with six different nuclear EOS. We analyzed the resulting observables to determine to which extent the EOS can be identified or constrained from such observations. For example, we used statistical distance measures on the mass distribution of neutron stars and black holes to find the EOS most favored by these observations. Additionally, we used a linear perturbation analysis to identify two characteristic frequencies, of the early- and late-time gravitational wave signal, that measure the surface gravity of the cold remnant neutron star, and simultaneously constrain the hot nuclear EOS.
In the study of atomic nuclei, nuclear charge radii provide intriguing physics insights into the evolution of nuclear structure far away from stability and pairing effects [1,2]. Furthermore, charge radii ,have been used as experimental input for the determination of V$_{ud}$ of the Cabibbo-Kobayashi-Maskawa (CKM) quark mixing matrix from superallowed nuclear $\beta$-decays [3]. In the Standard model of particle physics, the CKM matrix is predicted to be unitary but recent reviews of the matrix values [4] show $\approx2\sigma$ deviation for one of its unitarity tests, with the highest numerical contribution coming from $V_{ud}$. This contribution will present the recent work of combined measurements of the charge radii of $^{26,26m}$Al by means of Collinear Laser Spectroscopy (CLS) at the COLLAPS experiment at ISOLDE and at the IGISOL facility in Jyväskylä, Finland. CLS takes advantage of the interaction between the atomic nucleus and its surrounding electrons giving rise to the hyperfine structure. Thus, properties of nuclear ground states and long-lived isomers, including nuclear charge radii, can be inferred from measured hyperfine spectra. Prior to the present work, the charge radius of the superallowed $\beta$ emitter $^{26m}$Al was not known experimentally but had to be extrapolated from known nuclear charge radii to evaluate the theoretical isospin symmetry breaking (ISB) correction required for the determination of V$_{ud}$. The present measurements reveal a charge radius of $^{26m}$Al which differs by more than 4 standard deviations from the value assumed in previous ISB calculations. Consequently, this affects the corrected $\mathcal{F}$t value of $^{26m}$Al -- important for the estimation of V$_{ud}$ in the CKM matrix -- which is shifted by one standard deviation to \qty{3071.4\pm1.0}{\second}. References [1] M. Bissell et al., Physical Review Letters 2014, 113, 052502. [2] A. Koszorus et al., Physics Letters B 2021, 819, DOI 10.1016/j.physletb.2021.136439. [3] J. C. Hardy, I. S. Towner, Physical Review C 2020, 102, DOI 10.1103/PhysRevC.102.045501. [4] R.L. Workman et al. (Particle Data Group), Prog. Theor. Exp. Phys. 2022, 083C01 (2022) and 2023 update
The capabilities of ab initio many-body calculations for nuclear structure and reactions have expanded dramatically within recent years. We have seen first converged calculations for nuclei as heavy as Pb208, a first attempt at a mass table up to the iron region, as well as studies of fusion and reactions of light nuclei that are of astrophysical importance. Efforts are now focusing on nuclei with complex intrinsic deformation. The progress in many-body theory has been accompanied by advances in surrogate modeling that have opened up the door for large-scale parameter exploration and statistical uncertainty quantification. These developments are crucial for meaningful comparisons with experiments not only as facilities like FRIB push the boundaries of the nuclear chart, but also as ab initio nuclear theory inputs play an increasingly important role in precision fundamental symmetry research, for instance. In this talk, I will give a brief overview of the rich landscape of ab initio nuclear many-body theory, highlight key developments and achievements, and touch upon the challenges the community is facing in the years to come.
The high intensity proton accelerator facility at the Paul Scherrer Institute (PSI) in Switzerland provides high intensities of pions, muons and ultracold neutrons for fundamental atomic, nuclear and particle physics measurements. Aspects of the facility will be shown and some of the latest experimental results will be presented.
The Standard Model of particle physics is incredibly successful and glaringly incomplete. Among the questions left open is the striking imbalance of matter and antimatter in our universe, which inspires experiments to compare the fundamental properties of matter/antimatter conjugates with high precision. The BASE collaboration at the antiproton decelerator of CERN is performing such high-precision comparisons with protons and antiprotons. Using advanced cryogenic Penning traps, we have recently performed the most precise measurement of the proton-to-antiproton charge-to-mass ratio with a fractional uncertainty of 16 parts in a trillion. In another measurement, we have invented a novel spectroscopy method, that allowed for the first direct measurement of the antiproton magnetic moment with a fractional precision of 1.5 parts in a billion. Together with our last measurement of the proton magnetic moment this improves the precision of previous magnetic moment based tests of the fundamental CPT invariance by more than a factor of 3000. A time series analysis of the sampled magnetic moment resonance furthermore enabled us to set first direct constraints on the interaction of antiprotons with axion-like particles (ALPs), and most recently, we have used our ultra-sensitive single particle detection systems to derive constraints on the conversion of ALPs into photons. In parallel we are working on the implementation of new measurement technology to sympathetically cool antiprotons and to apply quantum logic inspired spectroscopy techniques. In addition to that, we are currently developing the transportable antiproton-trap BASE-STEP, to relocate antiproton spectroscopy experiments to dedicated precision laboratory space. I will give a general introduction to physics at the AD/ELENA facility of CERN and will review the recent results produced by BASE, with particular focus on recent developments towards an at least 10-fold improved measurement of the antiproton magnetic moment.
In 2017, a multimessenger era started with the first gravitational wave detection from the merger of two neutron stars (GW170817) and the rich electromagnetic follow-up. The most exciting electromagnetic counterpart was the kilonova. This provides an answer to the long-standing question of how and where heavy elements are produced in the universe. The neutron-rich material ejected during the neutron star merger undergoes an r-process (rapid neutron capture process) that produces heavy elements and a kilonova. Moreover, observations of abundances from the oldest stars reveal an additional r-process contribution of a rare and fast event, which could be core-collapse supernovae with strong magnetic fields, so called magneto-rotational supernovae. Now we can use neutron star mergers and core-collapse supernovae as cosmic laboratories to test nuclear physics under extreme conditions and to understand the origin and history of heavy elements. We combine hydrodynamic simulations of neutron star mergers and supernovae including state-of-the-art microphysics, with nucleosynthesis calculations involving extreme neutron-rich nuclei, and forefront observations of stellar abundances in the Milky Way and in orbiting dwarf galaxies. This opens up a new frontier to use the freshly synthesized elements to benchmark simulations against observations. The nucleosynthesis depends on astrophysical conditions (e.g., mass of the neutron stars) and on the microphysics included (equation of state and neutrino interactions). Therefore, comparing calculated abundances based on simulations to observations of the oldest stars and future kilonovae will lead to ground-breaking discoveries for supernovae, mergers, the extreme physics involved, and the origin of heavy elements.
A new high-power laser facility will be realised in Italy at the INFN-LNS laboratories with the main goal of producing radiation (protons, electrons, neutrons, gamma) for applications and basic science studies. The facility will also possess a distinctive feature (almost unique in the world) allowing for the concurrent utilization of accelerated ion beams (4 - 70 AMeV in energy) from conventional accelerators and highly energetic plasmas generated by lasers. In this talk, the status of the laser-driven proton/electron acceleration will be presented and the future I-LUCE (INFN Laser indUCEd radiation production) facility will be described together with some examples of future physics cases that could be investigated.
The thorium-229 nucleus contains an low-lying isomeric state, making it accessible to laser excitation. It is good candidate for the development of a nuclear clock [Peik and Tamm, EPL 61, 181 (2003)] which will enable testing fundamental principles in physics and practical applications (see e.g. [Thirolf,- J. Phys. B 52, 203001 (2019)]). The radiative decay of the thorium-229 isomer was observed at ISOLDE-CERN in a previous experiment by populating the isomer via the beta decay of actinium-229, implanting its shorter-lived decay precursor radium-229 in large bandgap crystals and observing the isomer’s VUV photons in a dedicated spectrometer. A reduced uncertainty of the isomer’s excitation energy (8.338±0.024 eV) and a first determination of the ionic half-life (670±102 s) in MgF2 was reported [Kraemer,- Nature 617, 706 (2023)]. During the follow-up experimental campaign in July 2023, seven crystals (including MgF2, CaF2, SiO2, AlN, LiSrAlF6) were tested, the energy was determined with better precision, and the half-life behavior of the VUV signal in the different crystals was studied. Preliminary results as well as future prospects will be discussed.
Rare kaon decays are among the most sensitive probes of both heavy and light new physics beyond the Standard Model description thanks to high precision of the Standard Model predictions, availability of very large datasets, and the relatively simple decay topologies. The NA62 experiment at CERN is a multi-purpose high-intensity kaon decay experiment, and carries out a broad rare-decay and hidden-sector physics programme. Recent NA62 results on searches for violation of lepton flavour and lepton number in kaon decays, and searches for production of hidden-sector mediators in kaon decays, are presented. Future prospects of these searches are discussed. Searches for visible decays of exotic mediators from data taken in beam-dump" mode with the NA62 experiment are also reported. The NA62 experiment can be run as abeam-dump experiment" by removing the kaon production target and moving the upstream collimators into a ``closed" position. More than $10^{17}$ protons on target have been collected in this way during a week-long data-taking campaign by the NA62 experiment. We report on recent results from analysis of this data, with a particular emphasis on Dark Photon and Axion-like particle Models.
The abstract is submitted on behalf of the NA62 Collaboration by A. Romano, chair of the NA62 Conference Committee. If it will be accepted as a talk, a speaker will be appointed as soon as possible.
The cylindrical-RWELL (C-RWELL) is a low material budget (O(1%) X0) cylindrical Inner Tracker based on the µ-RWELL technology. The µ-RWELL is a resistive MPGD composed of two PCBs: a mono-layer PCB acting as the cathode, defining the gas detector gap, and a µ-RWELL_PCB that couples in an unique structure the electron amplification (a well-patterned GEM-like matrix) and the readout stage. The C-RWELL is mainly based on the flexibility of the base material used for the manufacturing of its amplification/readout stage: 50 um thick APICAL foil clad on one side with copper and on the other with few nm of Diamond-Like Carbon (DLC). The readout is also realized on a flexible substrate coupled by a 50 um thick pre-preg layer to the amplification stage. The detector has been built in the framework of the WP5.4 of the European project EURIZON . The detector exhibits also other interesting features: the amplication stage is divided in three independent parts that can be, in case of damages, substituted saving the rest of the detector. Indeed the device can be “opened” to extract the cylindrical anode and complete the operation. These challenging features required huge technological efforts made in collaboration with LOSON S.r.l., a company leader in composite materials manufacturing. First tests have been carried on in the INFN LNF-DDG lab with cosmic-rays muons: a first evaluation of the performance will be shown.
The statistical hadronization model ThermalFist was applied to numerous hadron yields measured in p+p collisions at $\sqrt{s}$ = 8.8, 12.3 and 17.3 GeV, including recent yields of $\phi$ and $K^0_S$-mesons, measured by the NA61/SHINE Collaboration. We consistently used the energy-dependent widths of Breit-Wigner mass distributions of hadronic resonances. The canonical treatment of particles with open strangeness combined with the grand canonical approach for non-strange particles gave a moderately reasonable agreement with the measured yields, quantified by $\chi^2 / NDF \approx 2-6$, only when the volume of strange particles was allowed to vary freely. This volume is found to be greater than the one for non-strange matter for all the studied energies, effect not-excluded by femtoscopic analyses at higher collision energies.
This talk will be an overview of the physics of coherent elastic neutrino-nucleus scattering (CEvNS) and the current status and prospects of CEvNS experiments.
The heaviest neutron stars progressively tighten the constraints on the equation-of-state of strongly interacting, dense baryonic matter. Using the observational data base, results are presented of a detailed Bayes inference program, with focus on prerequisites and limitations for hypothetical phase transitions at the baryon densities realized in neutron star cores. Consequences for the possible structure and composition of matter under such conditions are discussed.
Exploring the limits of nuclear existence is one of the forefront topics in nuclear physics. One
limit is concerned with the heaviest nucleus that may exist. Theoretical models have predicted
that superheavy nuclei with Z ? 120 exist and feature a region of long-lived superheavy nuclides
around N = 184, the so-called the island of stability. Since the first predictions new elements
up to Z = 118, oganesson, have been discovered. Experimental data supports the concept of an
island of stability, but its extension and the longest half-life to be found remain unknown. Given
the uncertainties of predictions reaching far beyond well-known nuclei calls for more experimental
data to benchmark the theoretical models. As the heaviest nuclei exist thanks to their stabilizing
nuclear shell structure it is of interest to determine observables reflecting signatures of this shell
structure and study how they affect nuclear key properties. Among the experimentally accessible
quantities are, for example, nuclear binding energies that can be obtained from mass measurements.
Also, changes in nuclear charge radii that can be inferred from isotope shift measurements by laser
spectroscopy, and electromagnetic moments obtained from hyperfine spectroscopy are of interest.
All these properties usually display signatures of shell structure such as shell closures and the onset
of deformation. In recent years, mass measurements and laser spectroscopy studies have been
extended to the heaviest elements thanks to several technical and methodological developments
[1-3]. In my contribution I will present an overview of recent measurements studying the nuclear
structure around Z = 100 and N = 152 carried out at the GSI in Darmstadt, Germany.
[1] M. Block et al., Radiochimica Acta 107 (2019) 603.
[2] M. Block et al., Prog. Part. Nucl. Phys. 116 (2021) 103834.
[3] M. Block et al., Riv. Nuovo Cim. 45 (2022) 279.
The contributions of the SHIPTRAP, RADRIS, and JetRIS collaborations are gratefully acknowledged. This work
is supported in part by the German Ministry of Education and Research (BMBF) and by the European Union.
The close correspondence between neutron star matter pressure near the saturation density and the radii of typical neutron stars is an example of a semi-universal relation, as is the Yagi-Yunes I-Love relation connecting the moments of inertia and the tidal deformability of neutron stars. These relations are valid for all or nearly all equations of state to high precision. Using an extensive database of hundreds of Skyrme- and RMF-type nuclear interactions proposed over the last several decades, I will demonstrate several additional relations that could prove valuable in interpreting astronomical observations of neutron stars. For example, the central energy density and pressure of the maximum mass star are highly correlated with the maximum mass and its radius, plus the radius of a star with half the maximum mass. Other relations can be found that are able to predict the central energy density and the pressure of smaller mass stars using mass-radius information only. Such relations may allow the semi-analytic inversion of the mass-radius diagram.
In the last two decades, through technological, experimental and theoretical advances, the situation in experimental fission studies has changed dramatically. With the use of advanced production and detection techniques much more detailed and precise information can now be obtained for the traditional regions of fission research. Crucially, new regions of nuclei have become routinely accessible for fission studies, by means of radioactive ion beams. The talk will briefly introduce classical concepts of fission, followed by examples of recent developments in fission techniques, in particular the resurgence of multinucleon-transfer induced fission reactions with light and heavy ions, the emerging use of inverse-kinematic approaches, both at Coulomb and relativistic energies, and of fission studies with radioactive beams [1]. The emphasis on the fission-fragment mass and charge distributions will be made for low-energy fission. Such studies have become possible due to the development of several complementary experimental studies, including the β-delayed fission with laser-ionized mass-separated radioactive beams at ISOLDE(CERN) [2,3]. The unprecedented high-quality data for fission of heavy actinides, completely identified in Z and A, by means of reactions in inverse kinematics at FRS(GSI), SAMURAI(RIKEN, Japan), and VAMOS(GANIL, France) will be also reviewed. These experiments explored an extended range of heavy elements, covering both asymmetric, symmetric and transitional fission regions. The talk will conclude with the discussion of the new experimental fission facilities which are presently being brought into operation, along with promising 'next-generation' fission approaches, which might become available within the next decade [1]. [1] A.N. Andreyev, K. Nishio, K.-H. Schmidt, Reports on Progress in Physics, 81,1 (2018) [2] A.N. Andreyev et al, Physical Review Letters, 105, 252502 (2010) [3] A.N. Andreyev, M. Huyse, P. Van Duppen, Reviews of Modern Physics, 85, 1514 (2013)
The Cryogenic Underground Observatory for Rare Events (CUORE) is the first bolometric experiment searching for neutrinoless double-beta (0NBB) decay that has been able to reach the one-tonne mass scale. The detector, located at the LNGS in Italy, consists of an array of 988 TeO_2 crystals (~750 kg). CUORE began its first physics data run in 2017 at a base temperature of about 10 mK and has been steadily collecting data since. It released a new analysis of the search for 0NBB with two tonne-year of TeO_2 exposure in 2023, corresponding to the most sensitive measurement of 0NBB decay in Te-130 ever conducted. We find no evidence of 0NBB decay and set a lower bound of 3.3×10^{25} yr at a 90% credibility interval on the Te-130 half-life for this process. The next-generation of experiments aims at covering the Inverted-Ordering region of the neutrino mass spectrum, with sensitivities on the half-lives greater than 10^{27} years. CUPID (CUORE Upgrade with Particle IDentification) will search for the 0NBB decay of Mo-100 in scintillating Li_2MoO_4 crystals in the existing cryogenic infrastructure of CUORE. A total of about 1600 Li_2MoO_4 crystals, enriched in Mo-100 will be coupled to ~1700 light detectors to allow for the simultaneous readout of heat and light and hence for an effective particle identification. Numerous studies and R&D projects are currently ongoing in an coordinated effort aimed at finalizing the design of the CUPID detector and at assessing its performance and physics reach. In this talk, we present the recent result of CUORE and discuss the design and forthcoming steps towards the construction of the CUPID experiment.
Hyperon-hyperon (YY) and hyperon-nucleon (YN) interaction potentials play an important role in understanding the strangeness content of neutron star cores. YY and YN interactions are thoroughly studied at e.g. ALICE, which has the benefit of using a high energy proton beam to produce hyperons abundantly. However, further studies are needed since many of the interactions involving strangeness are not known. HADES (High-Acceptance Di-Electron Spectrometer) at GSI collected high-statistics proton-proton data in 2022 using a beam with 4.5 GeV kinetic energy. This lower energy is beneficial for creating the YY or YN system with low relative momentum, which is needed to access the potential. The Λ Λ reaction is currently being studied at HADES along with the reaction pp→p K+ K+ Ξ- [ π- Λ [p π-] ], which is currently being analyzed in order to investigate double strange YN interactions close to threshold. Measuring the latter reaction in p+p data is also important in order to explain excess yield measured in Ar+KCl and p+Nb reactions at HADES. This talk will address the hyperon physics related to the ongoing analyses at HADES and present selected results.
Nuclear inelastic interactions in carbon ion particle therapy treatments can lead to the fragmentation of the projectile, producing a non-negligible amount of dose deposition outside the planned target volume [1]. To improve the Monte Carlo simulation models adopted in the clinical treatment planning systems, the FOOT experiment of INFN [2] has been proposed for the measurement of the fragmentation cross sections of light ion beams (mainly 12C, 16O) in the range 200-700 MeV/u on C, C2H4. Other targets will be considered for measurements of interest for radioprotection in Space. The cross sections for the reactions on H can be extracted by performing a stoichiometric subtraction. By inverse kinematics the process of target fragmentation in p+C and p+O reactions, of interest for proton therapy, can be studied. The experimental setup is now practically completed. An overview of the status of the experiment and of some preliminary results will be presented. References [1] M. Durante and H. Paganetti, “Nuclear physics in particle therapy: a review”, Rep. Prog. Phys., vol. 79, no. 096702, 2016. [2] G Battistoni et al. “Measuring the impact of nuclear interaction in particle therapy and in radio protection in space: the foot experiment”, Frontiers in Physics, 8:555, 2021.
An accurate experimental determination of the neutron-skin thickness provides considerable constraints on the density dependence of the nuclear symmetry energy, which constrains the nuclear equation of state. However, one of the main systematic errors in measurements of the neutron-skin thickness of nuclei via parity-violating electron scattering comes from the beam-normal asymmetry, which in turn is heavily influenced by the Compton slope parameter. This talk will discuss the upcoming Mainz program to reduce the uncertainty in this slope parameter for various nuclei including 12C and 208Pb.
Chiral model calculations, assuming a partial restoration of chiral symmetry in a nuclear medium, predict modifications of meson properties within nuclei. This motivated a still ongoing widespread experimental campaign starting in the 1990’s to measure the properties of mesons in photon-, pion-, and proton-induced reactions on nuclei and in relativistic and ultra-relativistic heavy-ion collisions. Meson properties can be extracted from studying their decay or their production in the medium. The first approach is basically only applicable for the short-lived ρ-meson (τ≈1.4 fm/c) which mostly decays in the nuclear medium in spite of its recoil momentum. The in-medium properties of longer-lived mesons, decaying to a large extent outside of the nuclear medium can be extracted from their near-threshold yields and momentum distributions by comparing to reactions on the free nucleon and in comparison to model calculations. An overview will be given on experimentally determined in-medium mass shifts and broadening of all light mesons (K+, K0, K-, η, η’, ρ, ω, ϕ), allowing for the extraction of the real and imaginary part of the meson-nucleus potential. Based on the potential parameters, the chances for observing meson-nucleus bound states will be discussed. The most promising candidates appear to be the K-,η and η’ meson.
In muonic atoms, a single muon replaces all of the atomic electrons, resulting in a 2-body system whose hydrogen-like theory is very well understood. The large muon mass of 200 times the electron mass results in a 200^3 = 10 million fold improved sensitivity of muonic-atom energy levels to nuclear structure. Using laser spectroscopy, we have investigated the charge radii of Z=1 and 2 (H to 4He). Next we will determine the magnetic "Zemach" radius of the proton. In the near future we will measure Z=3 to 10 (Li to Ne) by means of X-ray spectroscopy with metallic magnetic calorimeters (MMCs), a new x-ray detector technology with vastly improved energy resolution. A novel target concept allows x-ray spectroscopy of radioactive atoms. I will report on some recent measurements with a Ge detector array.
Recent results have brought conclusive and/or intriguing answers to important questions in hot QCD. I will discuss some of those answers and the new questions that they pose, and will point to some of the upcoming new experimental facilities that should provide the next round of discoveries.
The difference in proton-proton and neutron-neutron scattering lengths contributes to understanding the charge-symmetry breaking of nuclear forces, yet the Coulomb-free proton-proton scattering length (app) cannot be measured directly and relies heavily on numerous and distinct theoretical techniques to remove the Coulomb contribution. We determined the Coulomb-free p-p scattering length from the half-off-the-energy-shell p-p scattering cross section measured at center-of-mass energies below 1 MeV using the quasi-free p + d→p + p + n reaction. The resulting difference in proton-proton and neutron-neutron scattering lengths suggests a lower charge symmetry breaking of nuclear forces than predicted so far. A model based on universality concepts has been developed to interpret this result in the framework of the short-range physics. Results will be presented and discussed.
The LHCb experiment has evolved into a true 'general purpose detector', with major contributions in the fields of heavy ion physics, hadron spectroscopy and high-pt electro-weak physics, in addition to its traditional focus on CP violation and rare processes in b and c decays. In this overview the physics highlights from the LHCb experiment from Run 1 and Run 2 will be introduced, and the status of the upgraded LHCb detector in Run 3 will be shown.
Neutron-rich matter exists naturally in neutron stars and some nuclei. It can also be created during mergers of neutron stars in space and collisions between two heavy nuclei in terrestrial nuclear laboratories. The nature and Equation of State (EOS) of such matter are still very poorly known while they have broad impacts on many interesting issues in both astrophysics and nuclear physics. In particular, nuclear symmetry energy encoding the energy cost to make the nuclear matter more neutron-rich has been the most uncertain part of the EOS of dense neutron-rich nucleonic matter. It affects the masses, radii, tidal deformations, cooling rates, and frequencies of various oscillation modes of isolated neutron stars as well as the strain amplitude and frequencies of gravitational waves from neutron star mergers. In this talk, we will discuss several outstanding issues and recent progress in probing the symmetry energy of dense neutron-rich matter as well as its impacts on the properties of nuclear reactions and neutron stars.
Although the gravitational interaction between matter and antimatter has been the subject of theoretical speculation since the discovery of the latter in 1928, only recently, for the first time, the ALPHA experiment was able to observe the effects of gravity on antimatter atoms, namely on anti-hydrogen. The experimental strategy is based on the balancing of the gravitational force with the magnetic one and it is conceptually simple: trap and accumulate anti-hydrogen atoms in the desired region, and then slowly release them by lowering the upper and lower magnetic potentials of a vertical trap. The effect of gravity manifests as a difference in the number of annihilation events from the anti-atoms escaping through the top or bottom of the trap. The results confirmed that anti-hydrogen behaves in accordance with gravitational attraction to Earth, ruling out repulsive anti-gravity between anti-hydrogen and the Earth. This measurement gives a test of the weak equivalence principle (WEP), a fundamental principle of Einstein's general theory of relativity, on antimatter. An overview of the experimental setup of the ALPHA experiment and details about the measurement procedure and the data analysis will be given.
High-energy physics is facing increasingly computational challenges in real-time event reconstruction for the near-future high-luminosity era, especially for charged particles track finding. In this talk, I will present a recently developed algorithm for track reconstruction based on the minimisation of an Ising-like Hamiltonian with a linear algebra approach: the track finding problem is translated into a sparse system of linear equations, which is suitable to be solved on a quantum computer, using the Harrow-Hassadim-Lloyd (HHL) algorithm. This approach can potentially provide an exponential speedup as a function of the number of input hits over its classical counterpart, in spite of the current limitations due to the HHL Hamiltonian simulation and readout problems. The performance of our algorithm has been assessed using simulated events in the LHCb Vertex Locator, while the quantum implementation has been tested using smaller toy-model events.
Amid the experimental results still needed to achieve a wide understanding of the Standard Model strong interaction mechanisms in the low-energy strangeness sector, the kaon-nucleon/nuclei interaction studies are a key component. The impact of these measurements ranges from various QCD models, like Chiral Symmetry Perturbation, Lattice QCD, etc., to nuclear physics and astrophysics.
The information in this scarcely explored field, from very low energies to the threshold and below, is accessible by studying the kaonic atoms, the kaon absorption processes and by low energy scattering of kaons on various nuclei.
These all make part of the KAONNIS scientific program, which encompasses a few experiments and addresses most of the above topics by taking advantage of several innovative detectors and of the unique low-energy kaon beam delivered by the DAɸNE collider in Frascati (Italy).
The first objective, followed by the SIDDHARTA/SIDDHARTA-2 collaborations, is extracting the charged anti-kaon nucleon scattering lengths by measuring the exotic X-ray transitions to the fundamental level in kaonic Hydrogen and kaonic Deuterium. Other X-ray lines in heavier kaonic atoms are investigated, as well. In parallel, the kaon multi-nucleon absorption is explored by the AMADEUS collaboration, while low-momenta kaon-nucleon/nuclei scattering study at DAFNE is part of an ongoing proposal. Last but not least, a precise determination of the charged kaon mass, still in debate between two incompatible measurements, is included between the SIDDHARTA-2 goals.
Micromegas (MICRO-MEsh GAseous Structures) are ionization gaseous detectors belonging to the Multi-Pattern Gaseous Detector (MPGD) family, which have been used in a large range of nuclear and particle physics experiments since their invention in 1996. It is parallel-plate structure divided into two regions by a micromesh suspended over an anode plane by insulator pillars: the conversion (drift) region where primary ionization by incident radiation occurs and the amplification region where electron multiplication through avalanches takes place. Using an appropriate neutron-to-charge convertor in the form of a thin layer deposited on the cathode electrode, or as part of the detectors gas, it is possible to detect neutrons, profiting at the same time from the advantages of MPGDs: high detection rate capabilities (>MHz/cm2), excellent spatial (<100 μm) and timing (~1 ns) resolution, very strong gamma-to-neutron suppression, radiation hardness and large area coverage with low cost. Applications of such detectors on neutron beam monitoring and profiling, as well as their use in neutron TOF experiments for cross-section measurements will be presented here. In some recent developments, such detectors are planned to be used in accelerators for machine protection (beam loss monitoring), while the fabrication of Micromegas detectors on a transparent substrate, like quartz, will allow for efficient and precise real-time neutron imaging using optical readout (CMOS cameras).