Physics of Particles and Nuclei Letters最新文献

Methods of processing a digital signal obtained from a four-electrode transverse position sensor of ion bunches during acceleration in a synchrotron are discussed. A technique has been developed for reconstructing the amplitude spectrum of betatron oscillations of an ion bunch in the case of a sensor displacement relative to the initial position determined during calibration. The results obtained are used to reconstruct the amplitude spectrum of betatron oscillations of a bunch after injection of xenon ions into the JINR booster synchrotron.

The formation of new nuclei and hypernuclei in heavy-ion collisions at high energies is analysed. We use the hypothesis of local chemical equilibrium in expanding nuclear matter. In this letter, the ultra-relativistic quantum molecular dynamics (UrQMD), the Dubna cascade model (DCM), and statistical multifragmentation model (SMM) are applied for theoretical calculations of nuclei and hypernuclei production. Good agreement with experimental data is obtained within our hybrid approach. Experiments planned for the future at FAIR, NICA, and other accelerators will provide an excellent opportunity for study of nuclei and hot (hyper-)matter.

The first images of the shadows of black holes have opened up new possibilities for testing extended theories of gravity. Using the Newman–Janis method, metrics with rotation for the (R + {{R}^{2}}) model with quantum field corrections are obtained. We have shown that not all previously obtained solutions are consistent with the experimental results of the Event Horizon Telescope. So the more accurate variant to select extended theories of gravity based on black hole rotation taking into account is proposed.

The Highly Granular Neutron Time-of-Flight Detector (HGND) at the BM@N experiment is under development for measuring the energy of neutrons produced in nucleus-nucleus collisions. For the first time, small prototype of the HGND was used in Xe + CsI at 3.0 and 3.8 A GeV run at the BM@N. The online real-time monitoring system recently developed and used for the HGND prototype is discussed.

Abstract

We report the cytotoxic effect of pulse duration and wavelength of UVB laser radiation from Li(Lu,Y)F₄:Ce laser on human skin fibroblasts. When performing the MTT test 24 h after irradiation, an increase in the viability parameter was observed. Flow cytometry showed that 80.8 ± 6.9% of cells have a damaged membrane and only 6.2 ± 2.2% reach the stage of late apoptosis, due to which they have the potential to restore the cytoplasmic membrane and subsequently divide.

The Spin Physics Detector is a collider experiment at NICA designed to study the spin structure of the proton and deuteron and other spin-related phenomena using polarized beams. The collision energy is up to 27 GeV and the luminosity is up to 10³² cm^–2 s^–1 in pp mode. Two scintillator-based detectors, Beam-Beam Counters (BBC), will be installed upstream and downstream the interaction point and will serve as a tool for beam diagnostics including local polarimetry. The BBCs will be designed as high granularity scintillation detectors. In this paper we present the tests of a BBC prototype based on the tiles with the green wavelength shifter and silicon photomultiplier (SiPM) readout. The prototype was tested with 1 × 1 mm² and 3 × 3 mm² SensL SiPM using CAEN FERS-5200 front-end readout system. Amplitude and time response to cosmic rays was compared for different tile configurations.

In this work we simulate the SPD NICA straw tracker detector response in the trigger-less regime using GEANT4 tools. We study the temporal structure of signals and investigate the vertex reconstruction efficiency using the simulation data. We develop a part of prototype software for event reconstruction at the stage of online data filtering.

ALICE3 is a next-generation heavy-ion experiment at the LHC, a successor of the ALICE experiment. It opens a high-precision domain to the strongly interacting matter studies. A set of ALICE3 measurements requires electron identification with high efficiency and purity, which will be performed using several complementing experimental techniques. Feasibility of electron identification using electromagnetic calorimeter clusters matched with tracks reconstructed in the central tracker is studied withing the ALICE3 simulation and analysis framework. Electron identification criteria are optimized against efficiency and hadron contamination suppression and applied to charmonium (1P) reconstruction in pp collisions via the ({{chi }_{{cJ}}} to J{text{/}}psi + gamma ) decay channel. Feasibility to reconstruct the charmonium states in pp collisions at the ALICE3 is discussed.

Masses of the ground and excited states of asymmetric fully heavy tetraquarks with open charm and/or bottom are calculated within the relativistic quark model, based on the quasipotential approach and QCD, and diquark-antidiquark picture of tetraquarks. The relativistic diquark-antidiquark interaction quasipotential takes into account the internal structure of the diquark and all spin-dependent and spin-independent relativistic corrections. It is shown, that there is a significant mixing between the asymmetric in flavor states of tetraquarks with the same total momentum-parity (({{J}^{P}})), but different full spins of the tetraquark ((S)) within the same excitation. The calculated masses of such tetraquarks are compared with the fall-apart decay thresholds into a pair of heavy mesons. The states that could be observed as narrow resonances are determined.

In this work, accretion onto spherically symmetric black hole in hybrid metric-Palatini (f(R))-gravity was studied within the framework of the Novikov–Thorn model. The average energy flux from the disk surface was numerically obtained for two cases: (V = 0) and (V = - frac{{{{mu }^{2}}}}{2}{{phi }^{2}} + frac{zeta }{4}{{phi }^{4}}). We also note that in each considered case, the prediction of the theory for this quantity are compared with similar result for the Schwarzschild black hole.