Kazuhiro Agatsuma, Kohei Suzuki, Takuya Sugimoto
et al.
Abstract For a commercial laser inertial fusion energy reactor, a highly repetitive operation in which many fuel pellets must be illuminated by laser spots. One of the most efficient ways to achieve this is to control the laser pointing by following fluctuations of the target position. The paper shows the precise control of laser pointing in the horizontal direction with a repetition rate of 10 Hz. Free-falling test pellets of 1 mm in diameter have been illuminated by a laser of 1.6 mm in diameter with cancellation of horizontal fluctuation over 4 mm. The difference in centroids between the laser spot and the illuminated test pellets is 86 μm (standard deviation). This corresponds to a 92% engagement within a 0.15 mm difference, which is a condition for successful nuclear fusions at the Hamamatsu facility. This is the proof-of-principle demonstration of the target-supply tracking and homing laser at a repetition rate of 10 Hz for the actualization of a commercial reactor.
In a recent paper [PLB 837 (2023) 137669] we showed that all measured ($1s_Λ$, $1p_Λ$) pairs of $Λ$ binding energies in $Λ$-hypernuclei across the periodic table, $12\leq A \leq 208$, can be obtained from a $Λ$-nucleus optical potential with only two adjustable $ΛN$ and $ΛNN$ parameters, associated with leading linear and quadratic terms in the nuclear density, derived by fitting $^{16}_{~Λ}$N binding energies. Here we extend the previous analysis by performing least-squares fits to the full set of data points. Consequences of suppressing $ΛNN$ interactions between `core' nucleons and `excess' neutrons are studied and related predictions are made for ($1s_Λ$, $1p_Λ$) binding energies in $^{40,48}_{~~~~Λ}$K, obtainable from upcoming $^{40,48}$Ca($e,e'K^+$) JLab experiments. We find $Λ$-nucleus partial potential depths of $D^{(2)}_Λ= -38.6\pm 0.8$~MeV ($ΛN$) and $D^{(3)}_Λ= 11.3\pm 1.4$~MeV ($ΛNN$), with a total depth $D_Λ= -27.3\pm 0.6$~MeV at nuclear-matter density $ρ_0$=0.17~fm$^{-3}$, consistently with our previous results. Extrapolation to higher nuclear densities and possible relevance to the `hyperon puzzle' in neutron-star matter are discussed.
A criterion for assessing the reliability of measurements of the Sachs form factor ratio using the Rosenbluth technique is proposed and applied to an analysis of three known experiments (Andivahis1994, Walker1994, Qattan2005) and a recent experiment on the CEBAF accelerator upgraded to 12 GeV at JLab (arXiv:2103.01842 [nucl-ex]). Based on the results of the JLab polarization experiments on measuring the ratio $μ_p G_E/G_M$ in the $\vec e p \to e \vec p$ process, in the kinematics of the SANE Collaboration experiment (2020) on the measurement of double spin asymmetry in the $\vec e \vec p \to e p$ process numerical calculations are performed for the $Q^2$ dependence of polarization transferred to the proton in the $e \vec p \to e \vec p$ process when the initial proton at rest is partially polarized along the direction of motion of the detected recoil proton.
G. Kh. Eyyubova, V. L. Korotkikh, A. M. Snigirev
et al.
A simple geometrical model with event-by-event fluctuations is suggested to study elliptical and triangular eccentricities in the initial state of relativistic heavy-ion collisions. This model describes rather well the ALICE and ATLAS data for Pb+Pb collisions at center-of-mass energy $\sqrt{s_{NN}} = 5.02$~TeV per nucleon pair, assuming that the second, $v_2$, and third, $v_3$, harmonics of the anisotropic flow are simply linearly proportional to the eccentricities $\varepsilon_2$ and $\varepsilon_3$, respectively. We show that the eccentricity $\varepsilon_3$ has a pure fluctuation origin and is substantially dependent on the size of the overlap area only, while the eccentricity $\varepsilon_2$ is mainly related to the average collision geometry. Elliptic flow, therefore, is weakly dependent on the event-by-event fluctuations everywhere except of the very central collisions 0--2%, whereas triangular flow is mostly determined by the fluctuations. The scaling dependence of the magnitude of the flow harmonics on atomic number, $v_n \propto A^{-1/3}$, is predicted for this centrality interval.
tion on GLP-1 receptor molecular imaging.Mol Imaging Biol. 2016;18:79–89. 7. Waser B, Reubi JC. Radiolabelled GLP-1 receptor antagonist binds to GLP-1 receptor-expressing human tissues. Eur J Nucl Med Mol Imaging. 2014;41:1166–1171. 8. Gotthardt M, Jansen TJP, Buitinga M, et al. Validation of exendin for beta cell imaging: ex vivo autoradiography of human pancreas demonstrates specific accumulation of radiolabeled exendin in islets of Langerhans [abstract]. Diabetologia. 2020;63:393. 9. K€orner M, Stockli M, Waser B, Reubi JC. GLP-1 receptor expression in human tumors and human normal tissues: potential for in vivo targeting. J Nucl Med. 2007;48:736–743. 10. Kirk RK, Pyke C, von Herrath MG, et al. Immunohistochemical assessment of glucagon-like peptide 1 receptor (GLP-1R) expression in the pancreas of patients with type 2 diabetes. Diabetes Obes Metab. 2017;19:705–712. 11. Lu G, Nishio N, van den Berg NS, et al. Co-administered antibody improves penetration of antibody-dye conjugate into human cancers with implications for antibody-drug conjugates. Nat Commun. 2020;11:5667.
Relativistic heavy-ion collisions create hot quark-gluon plasma as well as very strong electromagnetic (EM) and fluid vortical fields. The strong EM field and vorticity can induce intriguing macroscopic quantum phenomena such as chiral magnetic, chiral separation, chiral electric separation, and chiral vortical effects as well as the spin polarization of hadrons. These phenomena provide us with experimentally feasible means to study the nontrivial topological sector of quantum chromodynamics, the possible parity violation of strong interaction at high temperature, and the subatomic spintronics of quark-gluon plasma. These studies, both in theory and in experiments, are strongly connected with other subfields of physics such as condensed matter physics, astrophysics, and cold atomic physics, and thus form an emerging interdisciplinary research area. We give an introduction to the aforementioned phenomena induced by the EM field and vorticity and an overview of the current status of their experimental research in heavy-ion collisions. We also briefly discuss spin hydrodynamics as well as chiral and spin kinetic theories.
Through inelastic scattering cross section measurements for $^{42-51}$Ca on a carbon target at 280 MeV/nucleon recently, Tanaka {\it et al.} [ arXiv:1911.05262 [nucl-ex]], in a very significant experiment, have demonstrated large swelling of doubly magic $^{48}$Ca core in calcium isotopes beyond N=28. The matter radii observed in these experiments, are surprisingly much larger than the corresponding, already amazingly large charge radii of the same calcium isotopes, by Garcia {\it et al.} [Nat. Phys. 12 (2016) 594]. Here we propose a novel solution, wherein the breathing mode states $0^{+}$ of $^{48}$Ca, provide a global and consistent solution of this matter radii conundrum.
The study of the emitted particles, comparing pre-equilibrium and thermal components, is a useful tool to examine the nuclear structure. Possible clustering effects, which may change the expected decay chain probability, could be highlighted on the competition between different reaction mechanisms. The NUCL-EX Collaboration (INFN, Italy) has carried out an extensive research campaign on pre-equilibrium emission of light charged particles from hot nuclei. In this framework, the reactions O+Si, O+Si, F+Al at 7 MeV/u and O+Si at 8 MeV/u have been performed using the GARFIELD+RCo array at Legnaro National Laboratories.
The study of the emitted particles, comparing pre-equilibrium and thermal components, is a useful tool to examine the nuclear structure of emitters. Possible clustering effects, which may change the expected decay chain probability, could be highlighted on the competition between different reaction mechanisms. The NUCL-EX collaboration (INFN, Italy) has carried out an extensive research campaign on pre-equilibrium emission of light charged particles from hot nuclei. In this framework, the reactions 16O+30Si, 18O+28Si, 19F+27Al at 7 AMeV and 16O+30Si at 8 AMeV have been carried out using the GARFIELD+RCo array at Legnaro National Laboratories. Some anomalies in the α-particle emission channels have been evidenced in the measurement reported above, showing in an exclusive way the observed effects related to the entrance channels. The experimental results are compared to model prediction, for which the same filtering and complete event selection have been applied.
In the heavy nucleus 208Pb the 3- yrast and 4+ yrast states (Ex = 2615 and 4324 keV) are described by a rotating tetrahedron and eight more states at 4 < Ex < 8 MeV by rotating and vibrating tetrahedrons. The stiffness in three vibration modes is hundred times higher than for corresponding states in 16O by comparing the excitation energies from the prediction by the algebraic cluster model [Nucl. Phys. A 957 (2017) 154] and the splitting of a 2± doublet predicted to be degenerate.
The NUCL-EX collaboration is carrying out an extensive research program on preequilibrium emission of light charged particles from hot nuclei. The ultimate goal is to study how cluster structures affect nuclear reactions [1,2,3,4]. Indeed, a strong correlation between nuclear structure and reaction dynamics emerges when some nucleons or clusters of nucleons are emitted or captured [5]. At this purpose, the four reactions 16O+30Si, 16O+30Si, 18O+28Si and 19F +27Al have been measured at about 120 MeV projectile energy. Experimental data were collected at Legnaro National Laboratories, using the GARFIELD+RCo array, fully equipped with digital electronics [6]. Following an initial identification of particles and the energy calibration procedures, the complete analysis is being performed on an event-by-event basis. Experimental data are then compared to the theoretical predictions where events are generated by numerical codes based on pre-equilibrium and statistical models and then filtered through a software replica of the setup. Differences between the experimental data and the predicted data put into evidence effects related to the entrance channel and to the cluster nature of the colliding ions. After a general introduction on the experimental campaign, this contribution will focus on the preliminary results obtained so far.
With the experimental data collected by the ALICE collaboration in Pb-Pb collisions at a center-of-mass energy per nucleon pair 2.76 TeV for six different centralities (0-5$\%$, 5-10$\%$, 10-20$\%$, 20-40$\%$, 40-60$\%$ and 60-80$\%$), we investigate the scaling property of the pion, kaon and proton transverse momentum ($p_{\rm{T}}$) spectra at these centralities. We show that in the low $p_{\rm{T}}$ region with $p_{\rm T} \leq$ 2.75 (3.10 and 2.35) GeV/c the pion (kaon and proton) spectra exhibit a scaling behaviour independent of the centrality of the collisions. This scaling behaviour arises when these spectra are presented in terms of a suitable variable, $z=p_{\rm{T}}/K$. The scaling parameter $K$ is determined by the quality factor method and is parameterized by $a \langle N_{\rm{part}}\rangle^{b}$, where $\langle N_{\rm{part}}\rangle$ is the average value of the number of participating nucleons, $a$ and $b$ are free parameters, $b$ characterizes the rate at which $\textrm{ln} K$ changes with $\textrm{ln} \langle N_{\rm{part}}\rangle$. The values of $b$ for pions and kaons are consistent within uncertainties, while they are smaller than that for protons. In the high $p_{\rm{T}}$ region, due to the suppression of the spectra, a violation of the proposed scaling is observed going from central to peripheral collisions. The more peripheral the collisions are, the more clearly violated the proposed scaling becomes. In the framework of the colour string percolation model, we argue that the pions, kaons and protons originate from the fragmentation of clusters which are formed by strings overlapping and the cluster's fragmentation functions are different for different hadrons. The scaling behaviour of the pion, kaon and proton spectra in the low $p_{\rm T}$ region can be simultaneously explained by the colour string percolation model in a qualitative way.
The study of nuclear cluster states bound by valence neutrons is a field of recent large interest. In particular, it is important to study the pre-formation of α -clusters in α -conjugate nuclei and the dynamical condensation of clusters during nuclear reactions [1–5]. The NUCL–EX collaboration has recently initiated an experimental campaign of exclusive measurements of fusion–evaporation reactions with light nuclei as interacting partners. In collisions involving light systems, the low expected multiplicity of fragments increases the probability of achieving a quasi-complete reconstruction of the event. In particular the formation and decay modes of an excited 24 Mg system have been studied through two different reactions, 12 C (95 MeV)+ 12 C and 14 N (80.7 MeV)+ 10 B, which have been used to produce fused systems with nearly the same mass and excitation energy (~60 MeV). In particular, even the de-excitation of the Hoyle state in 12 C have been studied, both in peripheral (projectiles de-excitation) and in central collisions (six α-particles channel). Moreover, a research campaign studying pre-equilibrium emission of light charged particles and cluster properties of light and medium-mass nuclei has been carried out. For this purpose, a comparative study of the three nuclear systems 18 O+28 Si, 16 O+30 Si and 19 F+27 Al has been recently studied using the GARFIELD+RCo 4π setup [6]. The experimental data are compared with the predictions of simulated events generated with the statistical models (GEMINI++ and HFl) and through dynamical models like Stochastic Mean Field (SMF) and Antisymmetrized Molecular Dynamics (AMD) and filtered with a software replica of our apparatus in order to take into account the experimental conditions.
The study of nuclear cluster states bound by valence neutrons is a field of recent large interest. In particular, it is interesting to study the pre-formation of α-clusters in α-conjugate nuclei and the dynamical condensation of clusters during nuclear reactions. The NUCL-EX collaboration (INFN, Italy) is carrying out a research campaign studying pre-equilibrium emission of light charged particles and cluster properties of light and medium-mass nuclei. For this purpose, a comparative study of the three nuclear reactions: 16O + 30Si, 18O + 28Si and 19F + 27Al, has been recently carried out using the GARFIELD+RCo 4π setup. After a general introduction on the experimental campaign, the preliminary results for the three systems are presented.