Physics of Particles and Nuclei Letters最新文献

Abstract

This work aims at mathematically simulating the repair process of double-strand DNA breaks induced by rare ionizing radiation. A mathematical simulation of several stages of the cellular response to irradiation has been carried out: (i) Chinese hamster cells of the V79 line in the stationary phase of culture growth to the action of 250 keV X-ray irradiation and (ii) human carcinoma cells in the exponential phase of culture growth to (gamma )-Co(^{{60}}) irradiation. The induction and repair of DNA double-strand breaks and the kinetics of formation of incorrectly repaired DNA double-strand breaks are studied. The simulation data are compared with experimental values.

Abstract

Characteristic identities for (2)- and (3)-split Casimir algebra operators (D(2,1;alpha )) in representations (a{{d}^{{ otimes 2}}}) and (a{{d}^{{ otimes 3}}}) are found; projectors onto the invariant subspaces of these representations are constructed, and formulas for their supertraces are derived. All formulas agree with the universal description of subrepresentations of representations (a{{d}^{{ otimes 2}}}) and (a{{d}^{{ otimes 3}}}) of basic classical Lie superalgebras in terms of Vogel parameters.

Abstract

The contribution of the direct interaction vertex to the (Z to {{l}^{ + }}{{l}^{ - }}gamma ) process is extracted on basis of a measurement of differential distributions over the invariant mass ({{l}^{ pm }}gamma ) at the ATLAS detector. Models of CP-violating effective interaction and CP-preserving effective interaction are considered. The direct vertex can be seen as an effective description of loop corrections within the Standard Model. The contribution of the direct vertex in the CP-preserving model lead to ({text{Br}}left( {Z to {{e}^{ + }}{{e}^{ - }}gamma } right) = left( {3.81 pm 0.53} right) times {{10}^{{ - 5}}},) ({text{Br}}left( {Z to {{mu }^{ + }}{{mu }^{ - }}gamma } right) = left( {3.99 pm 0.47} right) times {{10}^{{ - 5}}}.) Adding an effective model to predictions of the modern PowHeg+PHOTOS and Sherpa 2.2 generators significantly improves the agreement with experimental results. The significance of the additive was 5 and 4.7 standard deviations for PowHeg+PHOTOS and Sherpa 2.2, respectively. The PowHeg+PHOTOS generator with the effective interaction additive describes the experimental data slightly better than other generators with the same type of effective additive.

Abstract

Prussian white is the promising cathode material for rechargeable sodium ion batteries. Here we study phase transitions in commercial Prussian White powder with particle size up to ~10 μm, which was chemically enriched with sodium, and synthesized sodium-enriched Prussian White with particle size of ~1 μm. X-ray diffraction was used to track structural changes during heating up to 250°C. Both powders were found to undergo the transformation of initial rhombohedral phase to dehydrated rhombohedral phase through a formation of cubic phase. Smaller particle size of the synthesized powder leads to more effective dehydration, which decreases temperatures of all phase transitions by ≈10°C compared to commercial Na-enriched Prussian White.

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.

The K⁺ → π⁰µ⁺νγ(K_µ3γ) and K⁺ → π⁰e⁺νγ (K_e3γ) decays are measured with OKA detector at the RF-separated 17.7 GeV/c momentum kaon beam from the U-70 synchrotron. The data obtained corresponds to the value of 2.62 × 10¹⁰ “live” kaons passing to the decay volume. The ratios of Br(K_µ3γ)/Br(K_µ3) and Br(K_e3γ)/Br(K_e3) are measured. The T-odd correlation ξ_πμγ (ξ_πeγ), which is the mixed product of the momenta of µ⁺(e⁺), π⁰, and γ in the kaon rest frame, is measured. The asymmetry of the distribution in ξ is characterized by the ratio A_ξ = (N₊ − N₋)/(N₊ + N₋), where N₊₍₋₎ is the number of events with positive (negative) ξ. The values of A_ξ for K_µ3γ and for K_e3γ is obtained.

In this overview, recent results of the ALICE collaboration on neutral meson and direct photon production are reported. The invariant cross section of ({{pi }^{0}}) and (eta ) meson production in pp collisions (sqrt s = 13) TeV are measured and compared to pQCD calculations. The direct photon production and two-photons HBT correlations in Pb–Pb (sqrt {{{s}_{{NN}}}} = 5.02) TeV are presented as well.

In order to better understand the dynamics of the quark-hadron phase transition in the presence of a magnetic field, the thermal behaviour of the non-perturbative QCD vacuum has been examined. The dynamical configuration of the resulting dual QCD vacuum and its flux tube configuration have been explored in order to investigate the non-perturbative properties of QCD. Within the context of dual QCD-based hadronic bag, which ensures the critical parameters and the accompanying critical sites for quark-hadron phase transition, related thermodynamic quantities and equation of state (EoS) to define quark matter have also been studied in presence of magnetic field.