This paper presents the characterisation and testing of the first wafer-scale monolithic stitched sensor (MOSS) prototype developed for the ALICE ITS3 upgrade that is to be installed during the LHC Long Shutdown 3 (2026-2030). The MOSS chip design is driven by the truly cylindrical detector geometry that imposes that each layer is built out of two wafer-sized, bent silicon chips. The stitching technique is employed to fabricate sensors with dimensions of 1.4 cm x 25.9 cm, thinned to 50 mu m. The chip architecture, the in-pixel front-end, the laboratory and in-beam characterisation, the susceptibility to single-event effects, and the series testing are discussed. The testing campaign validates the design of a wafer-scale stitched sensor and the performance of the pixel matrix to be within the ITS3 requirements. The MOSS chip demonstrates the feasibility of the ITS3 detector concept and provides insights for further optimisation and development.

The $(p,p\alpha )$ reaction offers a direct means to probe preformed $\alpha$-cluster structures in nuclei under quasi-free scattering conditions. Previous studies around 100 MeV provided valuable insights into $\alpha$ clustering, but quantitative comparison with microscopic cluster wave functions remained limited due to strong distortion effects. At higher energies, the reaction mechanism becomes simpler and the distorted-wave impulse approximation (DWIA) provides a more reliable framework for quantitative analysis. In the present work, the ${}<^>{40}$Ca$(p,p\alpha )$ reaction was measured at an incident energy of 392 MeV using the high-resolution Grand Raiden and Large Acceptance Spectrometer at RCNP. Despite the small cross section in this energy region, the achieved resolution allowed clear separation of the ground and excited states of the residual ${}<^>{36}$Ar nucleus, and corresponding momentum distributions were extracted. DWIA calculations using a Woods-Saxon $\alpha + {}<^>{36}$Ar bound-state wave function yielded an experimental spectroscopic factor of $S_{\mathrm{FAC}}<^>{\mathrm{WS}} = 0.51 \pm 0.05$, consistent with the previous result at 101.5 MeV ($0.52 \pm 0.11$). This agreement demonstrates that the reaction mechanism is well described across a wide energy range. The present study establishes the feasibility of high-precision $(p,p\alpha )$ measurements at several hundred MeV and highlights their potential as a quantitative probe of $\alpha$ clustering in medium-mass nuclei, forming the basis for systematic studies in both stable and unstable systems.

The proton-induced deuteron knockout reaction $(p,pd)$ provides a unique opportunity to exploit proton-neutron correlations and the deuteron cluster structure of nuclei. Direct deuteron knockout experiments on $<^>{12}$C and $<^>{16}$O under quasi-free scattering conditions have been carried out under the ONOKORO project using a 226-MeV proton beam at the Research Center for Nuclear Physics, Osaka, Japan. Deuterons from the knockout reaction, acting as clusters, were unambiguously detected at the focal plane of the Large Acceptance Spectrometer. Outgoing protons, following the knockout of clusters, were detected at the focal plane of the Grand Raiden spectrometer to correctly reconstruct the expected events. $(p,pd)$ reactions are established successfully, and excitation energy spectra for the residual nuclei $<^>{10}$B and $<^>{14}$N are obtained. Results showed that a large difference in transition strength toward the low-lying energy level of residual nuclei, including the ground state, was found in comparison to other studies. Theoretical calculations using the Proton-Induced KnockOut reaction calculation for Exclusive processes (PIKOE) package based on the distorted-wave impulse approximation are conducted to deduce the triple differential cross section of the $(p,pd)$ reaction, and experimental spectroscopic factors of the deuteron cluster are obtained by normalizing the experimental cross section to the theoretical computation. Consistent spectroscopic factors in comparison to shell-model expectations are obtained for transitions involving the orbital angular momentum $L=0$ of the cluster. The present work demonstrates that the $(p,pd)$ reactions at 226 MeV as a spectroscopic tool have an advantage in examining spectroscopic aspects of deuteron clustering and the mechanism to form a proton-neutron pair in the spin triplet state with negligible interference of final-state interactions and refraction effects.

Bent monolithic active pixel sensors are the basis for the planned fully cylindrical ultra low material budget tracking detector ITS3 of the ALICE experiment. This paper presents results from testbeam campaigns using high-energy particles to verify the performance of 50 mu m thick bent ALPIDE chips in terms of efficiency and spatial resolution. The sensors were bent to radii of 18, 24 and 30 mm, slightly smaller than the foreseen bending radii of the future ALICE ITS3 layers. An efficiency larger than 99.9% and a spatial resolution of approximately 5 mu m, in line with the nominal operation of flat ALPIDE sensors, is obtained at nominal operating conditions. These values are found to be independent of the bending radius and thus constitute an additional milestone in the demonstration of the feasibility of the planned ITS3 detector. In addition, a special geometry in which the beam particles graze the chip and traverse it laterally over distances of up to 3 mm is investigated.

The upgrade of the ALICE experiments Inner Tracking System (ITS3) aims to replace its innermost detection layers with bent wafer-scale CMOS MAPS sensors. This study examines the performance of ALPIDE chips, currently used in the ALICE ITS2, when operated in a bent configuration under realistic experimental conditions. Proton beams with energies of 80 MeV, 120 MeV and 200 MeV were used to study proton-proton elastic scattering on a polypropylene fiber target reconstructed using two opposing arms of trackers with sensors bent to radii of 18 mm, 24 mm and 30 mm. The measured low-momentum protons provided a testbed for investigating clustering behavior in high-energy loss events, where no significant impact of bending was observed on cluster size. Additionally, alignment strategies for bent detectors were evaluated using the distance of closest approach (DCA) and opening angle between scattered proton tracks as benchmarks. The achieved resolution matches expectations from simulations, confirming the suitability of bent MAPS sensors for future high-energy and nuclear physics applications.

Abstract We present a comprehensive study of deep‐sea bioluminescent organisms in the Cascadia Basin, Northeast Pacific Ocean, based on four years (2020–2023) of in situ measurements using STRings for Absorption length in Water instruments. Analysis of over 1.3 million camera images and continuous photomultiplier tube recordings revealed that bioluminescent activity at depths of 2.0–2.6 km is driven by mechanical stimulation from tidal currents, with emission rates showing strong periodicity across quaddiurnal, semidiurnal, and diurnal scales. Machine‐learning‐assisted chromatic characterization of emission peaks identified a taxonomic composition primarily consisting of blue‐emitting organisms (470–500 nm), likely including glass squid (Leachia lemur) and various planktonic species, alongside a non‐negligible population of yellow‐green emitters (5̃65 nm) tentatively associated with tomopteris polychaete worms. We quantified an effective organism abundance of , a value consistent with earlier indirect assessments but here confirmed through long‐term, direct observation. These findings establish a baseline for the biological optical background in the Cascadia Basin, providing critical parameters for the design and background‐modeling of large‐scale neutrino telescopes such as Pacific Ocean Neutrino Experiment (P‐ONE).

Inclusive e$^+$e$^-$ production has been studied with HADES in $\pi^-$ + p, $\pi^-$ + C and $\pi^- + \mathrm{CH}_2$ reactions, using the GSI pion beam at $\sqrt{s_{\pi p}}$ = 1.49 GeV. Invariant mass and transverse momentum distributions have been measured and reveal contributions from Dalitz decays of $\pi^0$, $\eta$ mesons and baryon resonances. The transverse momentum distributions are very sensitive to the underlying kinematics of the various processes. The baryon contribution exhibits a deviation up to a factor seven from the QED reference expected for the dielectron decay of a hypothetical point-like baryon with the production cross section constrained from the inverse $\gamma$ n$\rightarrow \pi^-$ p reaction. The enhancement is attributed to a strong four-momentum squared dependence of the time-like electromagnetic transition form factors as suggested by Vector Meson Dominance (VMD). Two versions of the VMD, that differ in the photon-baryon coupling, have been applied in simulations and compared to data. VMD1 (or two-component VMD) assumes a coupling via the $\rho$ meson and a direct coupling of the photon, while in VMD2 (or strict VMD) the coupling is only mediated via the $\rho$ meson. The VMD2 model, frequently used in transport calculations for dilepton decays, is found to overestimate the measured dielectron yields, while a good description of the data can be obtained with the VMD1 model assuming no phase difference between the two amplitudes. Similar descriptions have also been obtained using a time-like baryon transition form factor model where the pion cloud plays the major role.

We describe the recent experiments which claimed an observation of a tetra-neutron signal. Production reactions like transfer, knockout, fragmentation or photodisintegration have been used at very different experiments and facilities to form systems just made of neutrons. As a possible explanation of the partly contradicting results we suggest that some observed the bound ground state and some an unbound but still correlated state of the four neutrons at different exitation energy. We also refer to some of the theoretical works.

Radioactive nuclei with lifetimes on the order of millions of years can reveal the formation history of the Sun and active nucleosynthesis occurring at the time and place of its birth1,2. Among such nuclei whose decay signatures are found in the oldest meteorites, 205Pb is a powerful example, as it is produced exclusively by slow neutron captures (the s process), with most being synthesized in asymptotic giant branch (AGB) stars3-5. However, making accurate abundance predictions for 205Pb has so far been impossible because the weak decay rates of 205Pb and 205Tl are very uncertain at stellar temperatures6,7. To constrain these decay rates, we measured for the first time the bound-state β- decay of fully ionized 205Tl81+, an exotic decay mode that only occurs in highly charged ions. The measured half-life is 4.7 times longer than the previous theoretical estimate8 and our 10% experimental uncertainty has eliminated the main nuclear-physics limitation. With new, experimentally backed decay rates, we used AGB stellar models to calculate 205Pb yields. Propagating those yields with basic galactic chemical evolution (GCE) and comparing with the 205Pb/204Pb ratio from meteorites9-11, we determined the isolation time of solar material inside its parent molecular cloud. We find positive isolation times that are consistent with the other s-process short-lived radioactive nuclei found in the early Solar System. Our results reaffirm the site of the Sun's birth as a long-lived, giant molecular cloud and support the use of the 205Pb-205Tl decay system as a chronometer in the early Solar System.

Stable Tl205 ions have the lowest known energy threshold for capturing electron neutrinos (νe) of Eνe≥50.6 keV. The Lorandite Experiment (LOREX), proposed in the 1980s, aims at obtaining the longtime averaged solar neutrino flux by utilizing natural deposits of Tl-bearing lorandite ores. To determine the νe capture cross section, it is required to know the strength of the weak transition connecting the ground state of Tl205 and the 2.3 keV first excited state in Pb205. The only way to experimentally address this transition is to measure the bound-state beta decay (βb) of fully ionized Tl81+205 ions. After three decades of meticulous preparation, the half-life of the βb decay of Tl81+205 has been measured to be 291−27+33 days using the Experimental Storage Ring (ESR) at GSI, Darmstadt. The longer measured half-life compared to theoretical estimates reduces the expected signal-to-noise ratio in the LOREX, thus challenging its feasibility. Published by the American Physical Society 2024

Analogue test structures were fabricated using the Tower Partners Semiconductor Co. CMOS 65 nm ISC process. The purpose was to characterize and qualify this process and to optimize the sensor for the next generation of Monolithic Active Pixels Sensors for high-energy physics. The technology was explored in several variants which differed by: doping levels, pixel geometries and pixel pitches (10-25 mu m). These variants have been tested following exposure to varying levels of irradiation up to 3 MGy and 10(16) 1 MeV n(eq) cm(-2). Here the results from prototypes that feature direct analogue output of a 4 x 4 pixel matrix are reported, allowing the systematic and detailed study of charge collection properties. Measurements were taken both using Fe-55 X-ray sources and in beam tests using minimum ionizing particles. The results not only demonstrate the feasibility of using this technology for particle detection but also serve as a reference for future applications and optimizations.

The known I^{π}=8_{1}^{+}, E_{x}=2129-keV isomer in the semimagic nucleus ^{130}Cd_{82} was populated in the projectile fission of a ^{238}U beam at the Radioactive Isotope Beam Factory at RIKEN. The high counting statistics of the accumulated data allowed us to determine the excitation energy, E_{x}=2001.2(7)  keV, and half-life, T_{1/2}=57(3)  ns, of the I^{π}=6_{1}^{+} state based on γγ coincidence information. Furthermore, the half-life of the 8_{1}^{+} state, T_{1/2}=224(4)  ns, was remeasured with high precision. The new experimental information, combined with available data for ^{134}Sn and large-scale shell model calculations, allowed us to extract proton and neutron effective charges for ^{132}Sn, a doubly magic nucleus far-off stability. A comparison to analogous information for ^{100}Sn provides first reliable information regarding the isospin dependence of the isoscalar and isovector effective charges in heavy nuclei.

The accuracy of reaction theories used to extract properties of exotic nuclei from scattering experiments is often unknown or not quantified, but of utmost importance when, e.g., constraining the equation of state of asymmetric nuclear matter from observables as the neutron-skin thickness. In order to test the Glauber multiple-scattering model, the total interaction cross section of Image 1 on carbon targets was measured at initial beam energies of 400, 550, 650, 800, and 1000 MeV/nucleon. The measurements were performed during the first experiment of the newly constructed R3B (Reaction with Relativistic Radioactive Beams) experiment after the start of FAIR Phase-0 at the GSI/FAIR facility with beam energies of 400, 550, 650, 800, and 1000 MeV/nucleon. The combination of the large-acceptance dipole magnet GLAD and a newly designed and highly efficient Time-of-Flight detector enabled a precise transmission measurement with several target thicknesses for each initial beam energy with an experimental uncertainty of ±0.4%. A comparison with the Glauber model revealed a discrepancy of around 3.1% at higher beam energies, which will serve as a crucial baseline for the model-dependent uncertainty in future fragmentation experiments.

Hadron production ( π ^± , proton, Λ , K_S^0 , K^± ) in π ^- + C and π ^- + W collisions is investigated at an incident pion beam momentum of 1.7 GeV/c . This comprehensive set of data measured with HADES at SIS18/GSI significantly extends the existing world data on hadron production in pion induced reactions and provides a new reference for models that are commonly used for the interpretation of heavy-ion collisions. The measured inclusive differential production cross-sections are compared with state-of-the-art transport model (GiBUU, SMASH) calculations. The (semi-) exclusive channel π ^- + A →Λ + K_S^0 +X , in which the kinematics of the strange hadrons are correlated, is also investigated and compared to a model calculation. Agreement and remaining tensions between data and the current version of the considered transport models are discussed.

Stable ^{205}Tl ions have the lowest known energy threshold for capturing electron neutrinos (ν_{e}) of E_{ν_{e}}≥50.6  keV. The Lorandite Experiment (LOREX), proposed in the 1980s, aims at obtaining the longtime averaged solar neutrino flux by utilizing natural deposits of Tl-bearing lorandite ores. To determine the ν_{e} capture cross section, it is required to know the strength of the weak transition connecting the ground state of ^{205}Tl and the 2.3 keV first excited state in ^{205}Pb. The only way to experimentally address this transition is to measure the bound-state beta decay (β_{b}) of fully ionized ^{205}Tl^{81+} ions. After three decades of meticulous preparation, the half-life of the β_{b} decay of ^{205}Tl^{81+} has been measured to be 291_{-27}^{+33}  days using the Experimental Storage Ring (ESR) at GSI, Darmstadt. The longer measured half-life compared to theoretical estimates reduces the expected signal-to-noise ratio in the LOREX, thus challenging its feasibility.

Background: Experiments involving nuclear reactions in a storage ring offer exceptional possibilities for precise measurements in inverse kinematics. These experiments provide excellent angular and energy resolution by particle spectroscopy, in addition to high luminosities. However, the extremely low-pressure environment maintained in the storage rings poses significant difficulties for experiments employing detectors or any outgassing material in the ring. Purpose: We investigate nuclear reactions in inverse kinematics using the storage-ring technique. The reactions were induced by scattering of a 20 Ne beam off a hydrogen target at an energy of 50 MeV/u. Method: A beam of fully stripped 20 Ne ions was injected into the ESR storage ring at an energy of 50 MeV/u. The beam interacted with an internal hydrogen gas-jet target. An ultrahigh vacuum compatible detector setup was installed around the gas jet inside the ring to measure the recoiling particles generated by nuclear reactions. Results: Multiple reaction channels were observed during the experiment. In particular, we present the results from studies on elastic and inelastic scattering, as well as the neutron transfer reaction 20 Ne( p , d ) 19 Ne & lowast; . The experimental data were compared to calculations that took into account the most significant excited states, using a coupled-reaction channel approach. A very good agreement with the experimental data was achieved. Conclusions: The present results are the first demonstration of the investigation transfer reactions using detectors directly installed in the ring. This provides an important proof-of-principle for prospective studies with far-from- stability radioactive beams in the future.

The Coulomb excitation of Sn-124,Sn-128,Sn-130,Sn-132,Sn-134 isotopes in the electric field of a Pb target have been studied using the (RB)-B-3 setup as a part of the FAIR Phase-0 program. The experiment was motivated by the possibility of using the nuclear dipole response to infer valuable information on the slope of the symmetry energy of the nuclear equation of state. Measurements were performed in inverse kinematics at relativistic energies of 750 MeV/u and 904 MeV/u. The analysis method and preliminary results for the decay channel with a single outgoing neutron for Sn-124 are reported.

The matter radius of the doubly magic ^56 Ni was extracted from a measurement of the differential cross section by employing, for the first time, elastic proton scattering in inverse kinematics with a radioactive beam at E_kin=390.2 MeV/nucleon circulating in a storage ring and passing an internal hydrogen gas-jet target with a revolution frequency of around 2 MHz. The novel experimental scheme is based on UHV-compatible Si detectors operated as active vacuum windows, which were implemented in the ESR storage ring at GSI. A matter radius ^1/2=3.74^+0.03_-0.06 fm was extracted for the doubly-magic self-conjugate nucleus ^56 Ni.

High-precision measurements of flow coefficients v_n ( n = 1 - 4 ) for protons, deuterons and tritons relative to the first-order spectator plane have been performed in Au+Au collisions at √(s__NN)= 2.4 GeV with the High-Acceptance Di-Electron Spectrometer (HADES) at the SIS18/GSI. Flow coefficients are studied as a function of transverse momentum p_t and rapidity y_cm over a large region of phase-space and for several classes of collision centrality. A clear mass hierarchy, as expected by relativistic hydrodynamics, is found for the slope of v_1 , d v_1/d y^'|_y^' = 0 where y^' is the scaled rapidity, and for v_2 at mid-rapidity. Scaling with the number of nucleons is observed for the p_t dependence of v_2 and v_4 at mid-rapidity, which is indicative for nuclear coalescence as the main process responsible for light nuclei formation. v_2 is found to scale with the initial eccentricity ⟨ϵ _2⟩ , while v_4 scales with ⟨ϵ _2⟩ ^2 and ⟨ϵ _4⟩ . The multi-differential high-precision data on v_1 , v_2 , v_3 , and v_4 provides important constraints on the equation-of-state of compressed baryonic matter.

Nuclear fission is a complex dynamical process, whose description involves the coupling between intrinsic and collective degrees of freedom, as well as different quantum-mechanical phenomena. For this reason, to this day it still lacks a satisfactory and complete microscopic description. In addition to the importance of describing fission itself, studies of the r-process in astrophysics depend on fission observables to constrain the theoretical models that explain the isotopic abundances in the Universe. To improve on the existing data, fission reactions of heavy nuclei in inverse kinematics are produced in quasi-free (p,2p) scattering reactions, which induce fission through particle-hole excitations that can range from few to tens of MeV. In order to study the evolution of the fission yields with temperature, the excitation energy of the fissioning system must be reconstructed, which is possible by measuring the four-momenta of the two outgoing protons. Performing this kind of experiment requires a complex experimental setup, providing full isotopic identification of both fission fragments and an accurate measurement of the momenta of the two outgoing protons. This was realized recently at the GSI/FAIR facility and some of the results obtained for the charge distributions are presented in this work.