The properties of atomic nuclei are determined by interactions between nucleons at low resolution and quarks and gluons at high resolution. Short-range two-nucleon correlations (SRC) bridge these approaches, representing a specific type of short-range fluctuations, when two nucleons are separated by distances comparable to their radii and have momenta higher than Fermi level. The results from electron scattering experiments have shown that the SRC effect is important for the behavior of multiparticle systems, nucleon-nucleon interaction, and the structure of nucleons. Modern SRC studies with ion beams and liquid hydrogen targets allow for the analysis of the properties of nuclear fragments after quasi-elastic knockout of nucleons or SRC from the beam ions thus ensuring new observables and ways to investigate the fine structure of nuclei. The first SRC experiment at BM@N in JINR (2018) demonstrated that the detection of the 11B nucleus in the final state is a sign of scattering on a "transparent" carbon nucleus, and 25 observed events confirmed the SRC properties known from electron experiments. Currently, the analysis of the second SRC experiment at BM@N (2022) with an improved setup is ongoing, and the new SRC measurement with polarized deuteron beam in a new experimental area is being planned and prepared. This article discusses the historical insight in the problem of nuclear structure and the development of the SRC model, as well as the status and prospects of the SRC physics program at JINR (Dubna, Russia) within the current international SRC effort.

The procedure of reconstruction for coordinate detectors of SRC setup at BM@N was developed for both simulated and experimental data measured in 2018. Multiwire proportional chambers and silicon detectors were located upstream of the analyzing magnet at the SRC at BM@N setup. The developed algorithms were added to the official software. The reconstruction results were compared with the simulation. The main characteristics of the coordinate detectors upstream the analyzing magnet were evaluated and analyzed.

BM@N is the first operating fix-target experiment at the future NICA collider facility at JINR (Dubna, Russia). BM@N is using ion beams from the Nuclotron accelerator ring to study the properties of cold dense baryonic matter. In 2017 the physics program of BM@N was extended by studies of Short-Range Correlations (SRC) in carbon nuclei. The first SRC measurement took place in 2018, and the first results were published in 2021 [1]. The second measurement of SRC in inverse kinematics planned for fall 2021 aims at measuring absolute cross-sections, improving resolutions, and increasing the statistics by at least an order of magnitude. A new calorimeter for proton-pion separation consisting of the large area neutron detector (LAND) [2] modules will be used for the two-arm spectrometer. The location of the new calorimeter right next to the SP-41 analyzing magnet requires protection of the photomultiplier tubes (PMT) at the ends of the calorimeter modules from the external magnetic field. A detailed magnetic field simulation within Ansoft Maxwell 15.0 allowed to estimate the magnetic field magnitude in the area of PMTs and confirm that a passive magnetic shielding is enough to avoid gain loss in the PMTs.

The GlueX experiment at Jefferson Laboratory aims to perform quantitative tests of non-perturbative QCD by studying the spectrum of light-quark mesons and baryons. A Detector of Internally Reflected Cherenkov light (DIRC) was installed to enhance the particle identification (PID) capability of the GlueX experiment by providing clean π/K separation up to 3.7 GeV/c momentum in the forward region (θ < 11°), which will allow the study of hybrid mesons decaying into kaon final states with significantly higher efficiency and purity. The new PID system is constructed with radiators from the decommissioned BaBar DIRC counter, combined with new compact photon cameras based on the SuperB FDIRC concept. The full system was successfully installed and commissioned with beam during 2019/2020. The initial PID performance of the system was evaluated and compared to one from Geant4 simulation.

The GLUEX experiment at Jefferson Lab has been designed to study photoproduction reactions with a 9-GeV linearly polarized photon beam. The energy and arrival time of beam photons are tagged using a scintillator hodoscope and a scintillating fiber array. The photon flux is determined using a pair spectrometer, while the linear polarization of the photon beam is determined using a polarimeter based on triplet photoproduction. Charged-particle tracks from interactions in the central target are analyzed in a solenoidal field using a central straw-tube drift chamber and six packages of planar chambers with cathode strips and drift wires. Electromagnetic showers are reconstructed in a cylindrical scintillating fiber calorimeter inside the magnet and a lead-glass array downstream. Charged particle identification is achieved by measuring energy loss in the wire chambers and using the flight time of particles between the target and detectors outside the magnet. The signals from all detectors are recorded with flash ADCs and/or pipeline TDCs into memories allowing trigger decisions with a latency of 3.3 mu s. The detector operates routinely at trigger rates of 40 kHz and data rates of 600 megabytes per second. We describe the photon beam, the GLUEX detector components, electronics, data-acquisition and monitoring systems, and the performance of the experiment during the first three years of operation.

Particle knockout scattering experiments(1,2) are fundamental for mapping the structure of atomic nuclei(2-6), but their interpretation is often complicated by initial- and final-state interactions of the incoming and scattered particles(1,2,7-9). Such interactions lead to reduction in the scattered particle flux and distort their kinematics. Here we overcome this limitation by measuring the quasi-free scattering of 48 GeV c(-112)C ions from hydrogen. The distribution of single protons is studied by detecting two protons at large angles in coincidence with an intact B-11 nucleus. The B-11 detection suppresses the otherwise large distortions of reconstructed single-proton distributions induced by initial- and final-state interactions. By further detecting residual B-10 and Be-10 nuclei, we also identified short-range correlated nucleon-nucleon pairs(9-13) and provide direct experimental evidence for separation of the pair wavefunction from that of the residual many-body nuclear system(9,14). All measured reactions are well described by theoretical calculations that include no distortions from the initial- and final-state interactions. Our results showcase the ability to study the short-distance structure of short-lived radioactive nuclei at the forthcoming Facility for Antiproton and Ion Research (FAIR)(15) and Facility for Rare Isotope Beams (FRIB)(16) facilities, which is relevant for understanding the structure and properties of nuclei far from stability and the formation of visible matter in the Universe.

Nucleon knockout reactions with high energy probes are widely used to reveal the inner structure of nuclei, however, they cannot be applied to study unstable nuclei. We recently demonstrated the feasibility to access single particle and short-range correlation (SRC) properties in nuclei with hadronic probes in inverse kinematics, opening the pathway for such studies in short-lived nuclei at upcoming accelerator facilities. The experiment was carried out using the BM@N setup at JINR. A 12C beam at 4 GeV/c/u impinged on a liquid hydrogen target using a kinematically complete reaction. We show that by selecting the fragment in the $$^{{12}}$$ C( $$p$$ , $$2p$$ ) $$^{{11}}$$ B reaction, limitations posed by final-state interactions are overcome and single nucleon properties are probed in a single-step knockout reaction. The ground-state distributions are in agreement with theoretical calculations. We probe SRCs in the same way by the break up of SRC pairs in $$^{{12}}$$ C( $$p$$ , $$2pN$$ ) $$^{{10}}$$ B/ $$^{{10}}$$ Be reactions. We not only identify SRCs in such kinematical conditions for the first time but also deduce factorization and other pair properties from direct measurements. The ongoing analysis continues with the study of multi-fragmentation following quasielastic and SRC pair removal, and with 4-fold coincidence events including the recoil neutron being detected. We are also conducting studies to optimize the experimental conditions for the next scheduled beam time in 2021.

We report the first measurement of the (e,e^{'}p) three-body breakup reaction cross sections in helium-3 (^{3}He) and tritium (^{3}H) at large momentum transfer [⟨Q^{2}⟩≈1.9  (GeV/c)^{2}] and x_{B}>1 kinematics, where the cross section should be sensitive to quasielastic (QE) scattering from single nucleons. The data cover missing momenta 40≤p_{miss}≤500  MeV/c that, in the QE limit with no rescattering, equals the initial momentum of the probed nucleon. The measured cross sections are compared with state-of-the-art ab initio calculations. Overall good agreement, within ±20%, is observed between data and calculations for the full p_{miss} range for ^{3}H and for 100≤p_{miss}≤350  MeV/c for ^{3}He. Including the effects of rescattering of the outgoing nucleon improves agreement with the data at p_{miss}>250  MeV/c and suggests contributions from charge-exchange (SCX) rescattering. The isoscalar sum of ^{3}He plus ^{3}H, which is largely insensitive to SCX, is described by calculations to within the accuracy of the data over the entire p_{miss} range. This validates current models of the ground state of the three-nucleon system up to very high initial nucleon momenta of 500  MeV/c.

The past few years has seen tremendous progress in our understanding of short-range correlated (SRC) pairing of nucleons within nuclei, much of it coming from electron scattering experiments leading to the break-up of an SRC pair. The interpretation of these experiments rests on assumptions about the mechanism of the reaction. These assumptions can be directly tested by studying SRC pairs using alternate probes, such as real photons. We propose a 30-day experiment using the Hall D photon beam, nuclear targets, and the GlueX detector in its standard configuration to study short-range correlations with photon-induced reactions. Several different reaction channels are possible, and we project sensitivity in most channels to equal or exceed the 6 GeV-era SRC experiments from Halls A and B. The proposed experiment will therefore decisively test the phenomena of np dominance, the short-distance NN interaction, and reaction theory, while also providing new insight into bound nucleon structure and the onset of color transparency.

This year we start assembling the DIRC detector to upgrade the particle identification capabilities in the forward region of the GlueX detector in Hall D at Jefferson Lab. The main components of the GlueX DIRC are the four bar boxes (reused from the decommissioned BaBar DIRC) and two photon cameras, which were designed based on the prototype for the SuperB FDIRC. The delicate bar boxes have already arrived at JLab from SLAC, where they have been stored for the last ten years. They will be attached to the newly built photon cameras and installed in Hall D already for the 2019 spring run. We present the status of the GlueX DIRC project including the ongoing R&D and the plan for the future.

The GLUEX experiment is located in experimental Hall D at Jefferson Lab (JLab) and provides a unique capability to search for hybrid mesons in high-energy photoproduction, utilizing a ∼9 GeV linearly polarized photon beam. The initial, low-intensity phase of GLUEX was recently completed and a high-intensity phase has begun in 2020 which includes an upgraded kaon identification system, known as the DIRC (Detection of Internally Reflected Cherenkov light), utilizing components from the decommissioned BaBar DIRC. The identification of kaon final states will significantly enhance the GLUEX physics program, to aid in inferring the quark flavor content of conventional (and potentially hybrid) mesons. In these proceedings, we describe the installation of the GLUEX DIRC and the analysis of initial commissioning data.

The GlueX experiment takes place in experimental Hall D at Jefferson Lab (JLab). With a linearly polarized photon beam of up to 12 GeV energy, GlueX is a dedicated experiment to search for hybrid mesons via photoproduction reactions. The low-intensity (Phase I) of GlueX was recently completed; the high-intensity (Phase II) started in 2020 including an upgraded particle identification system, known as the DIRC (Detection of Internally Reflected Cherenkov light), utilizing components from the decommissioned BaBar experiment. The identification and separation of the kaon final states will significantly enhance the GlueX physics program, by adding the capability of accessing the strange quark flavor content of conventional (and potentially hybrid) mesons. In these proceedings, we report that the installation and commissioning of the DIRC detector has been successfully completed.

We report measurements of the photon beam asymmetry $\mathrm{\ensuremath{\Sigma}}$ for the reaction $\stackrel{P\vec}{\ensuremath{\gamma}}p\ensuremath{\rightarrow}{K}^{+}{\mathrm{\ensuremath{\Sigma}}}^{0}$(1193) using the GlueX spectrometer in Hall D at Jefferson Lab. Data were collected by using a linearly polarized photon beam in the energy range of 8.2--8.8 GeV incident on a liquid hydrogen target. The beam asymmetry $\mathrm{\ensuremath{\Sigma}}$ was measured as a function of the Mandelstam variable $t$, and a single value of $\mathrm{\ensuremath{\Sigma}}$ was extracted for events produced in the $u$ channel. These are the first exclusive measurements of the photon beam asymmetry $\mathrm{\ensuremath{\Sigma}}$ for the reaction in this energy range. For the $t$ channel, the measured beam asymmetry is close to unity over the $t$ range studied, $\ensuremath{-}t=(0.1--1.4)\phantom{\rule{3.33333pt}{0ex}}$($\mathrm{GeV}/{c)}^{2}$, with an average value of $\mathrm{\ensuremath{\Sigma}}=1.00\ifmmode\pm\else\textpm\fi{}0.05$. This agrees with theoretical models that describe the reaction via the natural-parity exchange of the ${K}^{*}$(892) Regge trajectory. A value of $\mathrm{\ensuremath{\Sigma}}=0.41\ifmmode\pm\else\textpm\fi{}\phantom{\rule{3.33333pt}{0ex}}0.09$ is obtained for the $u$ channel integrated up to $\ensuremath{-}u=2.0$ ($\mathrm{GeV}/{c)}^{2}$.

We report measurements of the photon beam asymmetry Σ for the reaction γp→K+Σ0 (1193) using the GlueX spectrometer in Hall D at Jefferson Lab. Data were collected by using a linearly polarized photon beam in the energy range of 8.2–8.8 GeV incident on a liquid hydrogen target. The beam asymmetry Σ was measured as a function of the Mandelstam variable t , and a single value of Σ was extracted for events produced in the u channel. These are the first exclusive measurements of the photon beam asymmetry Σ for the reaction in this energy range. For the t channel, the measured beam asymmetry is close to unity over the t range studied, − t = ( 0.1 – 1.4 ) ( GeV / c ) 2 , with an average value of Σ = 1.00 ± 0.05 . This agrees with theoretical models that describe the reaction via the natural-parity exchange of the K ∗ (892) Regge trajectory. A value of Σ = 0.41 ± 0.09 is obtained for the u channel integrated up to − u = 2.0 ( GeV / c ) 2 .

We report measurements of the photon beam asymmetry Sigma for the reaction (gamma) over right arrowp -> K+Sigma(0) (1193) using the GlueX spectrometer in Hall D at Jefferson Lab. Data were collected by using a linearly polarized photon beam in the energy range of 8.2-8.8 GeV incident on a liquid hydrogen target. The beam asymmetry Sigma was measured as a function of the Mandelstam variable t, and a single value of Sigma was extracted for events produced in the u channel. These are the first exclusive measurements of the photon beam asymmetry Sigma for the reaction in this energy range. For the t channel, the measured beam asymmetry is close to unity over the t range studied, -t = (0 .1-1 .4) (GeV/c)(2) , with an average value of Sigma = 1 .00 +/- 0 .05. This agrees with theoretical models that describe the reaction via the natural-parity exchange of the K*(892) Regge trajectory. A value of Sigma = 0 .41 +/- 0 .09 is obtained for the u channel integrated up to -u = 2 .0 (GeV/c)(2).

We report measurements of the photon beam asymmetry Σ for the reaction γ⃗ p→ K^+Σ^0(1193) using the GlueX spectrometer in Hall D at Jefferson Lab. Data were collected using a linearly polarized photon beam in the energy range of 8.2-8.8 GeV incident on a liquid hydrogen target. The beam asymmetry Σ was measured as a function of the Mandelstam variable t, and a single value of Σ was extracted for events produced in the u-channel. These are the first exclusive measurements of the photon beam asymmetry Σ for the reaction in this energy range. For the t-channel, the measured beam asymmetry is close to unity over the t-range studied, -t=(0.1-1.4)(GeV/c)^2, with an average value of Σ = 1.00± 0.05. This agrees with theoretical models that describe the reaction via the natural-parity exchange of the K^*(892) Regge trajectory. A value of Σ = 0.41 ± 0.09 is obtained for the u-channel integrated up to -u=2.0 (GeV/c)^2.

NICA-Nuclotron (Nuclotron-based Ion Collider fAility) is a new accelerator complex being constructed at the Joint Institute for Nuclear Research (Dubna, Russia) to study properties of dense baryonic matter. BM@N (Baryonic Matter at Nuclotron) is the first fixed target experiment at the NICA-Nuclotron facility. The aim of the experiment is to study collisions of relativistic ion beams of the kinetic energy from 1 to 4.5 AGeV with fixed targets. BM@N energies are perfectly suitable for strange hypernuclei investigation. This year BM@N started a new physics program aiming at studying the Short Range Correlations (SRC). SRC are brief fluctuations of two nucleons with high and opposite momenta, where each of them is higher than the Fermi momentum for the given nucleus, and the center of mass momentum is close to zero. The presence of SRC pairs within nuclei and their properties have important implications for nuclear physics, high energy physics, and astrophysics. The BM@N setup uses a carbon beam hitting a liquid hydrogen target, which makes it possible to detect the residual nucleus after hard knock-out of the two SRC nucleons. We present an overview of the main detection systems used for the SRC measurement as well as the first results from the tracking detectors.

This documents describes the technical design and the expected performance of the Barrel DIRC detector for the PANDA experiment. The Barrel DIRC will provide hadronic charged particle identification in the polar angle range of $22^\circ$ to $140^\circ$ for particle momenta between 0.5 GeV/c and 3.5 GeV/c. The design is based on the successful BaBar DIRC with several key improvements. The performance and system cost were optimized in detailed detector simulations and validated with full system prototypes using particle beams at GSI and CERN. The final design meets or exceeds the PID goal of clean $π/K$ separation with at least 3 standard deviations over the entire phase space of charged kaons in the Barrel DIRC.

The (P) over bar ANDA (anti-Proton ANnihiliation at DArmstadt) experiment will be one of the four flagship experiments at the new international accelerator complex FAIR (Facility for Antiproton and Ion Research) in Darmstadt, Germany. (P) over bar ANDA will address fundamental questions of hadron physics and quantum chromodynamics using high-intensity cooled antiproton beams with momenta between 1.5 and 15 GeV/c and a design luminosity of up to 2 x 10(32) cm(-2) S-1. Excellent particle identification (PID) is crucial to the success of the (P) over bar ANDA physics program. Hadronic PID in the barrel region of the target spectrometer will be performed by a fast and compact Cherenkov counter using the detection of internally reflected Cherenkov light (DIRC) technology. It is designed to cover the polar angle range from 22 degrees to 140 degrees and will provide at least 3 standard deviations (s.d.) pi/K separation up to 3.5 GeV/c, matching the expected upper limit of the final state kaon momentum distribution from simulation. This documents describes the technical design and the expected performance of the (P) over bar ANDA Barrel DIRC detector. The design is based on the successful BaBar DIRC with several key improvements. The performance and system cost were optimized in detailed detector simulations and validated with full system prototypes using particle beams at GSI and CERN. The final design meets or exceeds the PID goal of clean pi/K separation with at least 3 s.d. over the entire phase space of charged kaons in the Barrel DIRC.