International Journal of Modern Physics E

This paper delves into the history of MARS photon-counting CT and its technology origins in particle physics at the European Organization for Nuclear Research (CERN). The story begins at CERN, a world-class facility for research into fundamental physics. In the 1960s, charged particle experiments at CERN involved the slow and labor-intensive work of examining millions of photographs from bubble or spark chambers. In the 1970s, semiconductor detector technology changed nuclear and particle physics, and the world at large. As its name implies, semiconductor material conducts current, but this current can be modified, especially by a quantum of light or other radiation. During the development of semiconductor detector technology, the potential benefit of detecting X-ray photons became evident, leading to the development of the Medipix family of imaging devices in the 1990s. In the early 2000s, researchers from New Zealand took the Medipix detector and began to research and develop spectral molecular imaging for the clinic. Their work produced the MARS photon-counting CT, which promises to significantly advance current CT, develop a new standard of care, and improve health outcomes for millions of patients world-wide. Taking MARS to the clinic will be discussed, including investigation of potential clinical applications and the future direction of MARS technology.

This is a concise introduction to the topic of nonextensive Tsallis statistics meant especially for those interested in its relation to high-energy proton–proton, proton–nucleus and nucleus–nucleus collisions. The three types of Tsallis statistics are reviewed. Only one of them is consistent with the fundamental hypothesis of equilibrium statistical mechanics. The single-particle distributions associated with it, namely Boltzmann, Fermi–Dirac and Bose–Einstein, are derived. These are not equilibrium solutions to the conventional Boltzmann transport equation which must be modified in a rather nonintuitive manner for them to be so. Nevertheless, the Boltzmann limit of the Tsallis distribution is extremely efficient in representing a wide variety of single-particle distributions in high-energy proton–proton, proton–nucleus and nucleus–nucleus collisions with only three parameters, one of them being the so-called nonextensitivity parameter $q$. This distribution interpolates between an exponential at low transverse energy, reflecting thermal equilibrium, to a power law at high transverse energy, reflecting the asymptotic freedom of Quantum Chromodynamics (QCD). It should not be viewed as a fundamental new parameter representing nonextensive behavior in these collisions.

Transverse momentum spectra of different types of identified charged particles in central Gold–Gold (Au–Au) collisions and inelastic (INEL) or nonsingle diffractive (NSD) proton–proton (pp) collisions at the Relativistic Heavy Ion Collider (RHIC), as well as in central and peripheral Lead–Lead (Pb–Pb) collisions, and INEL or NSD pp collisions at the Large Hadron Collider (LHC) are analyzed by the blast-wave model with Tsallis statistics. The model results are approximately in agreement with the experimental data measured by STAR, PHENIX and ALICE Collaborations in special transverse momentum ranges. Kinetic freeze-out (KFO) temperature and transverse flow velocity are extracted from the transverse momentum spectra of the particles. It is shown that KFO temperature of the emission source depends on mass of the particles, which reveals the mass-dependent KFO scenario in collisions at RHIC and LHC. Furthermore, the KFO temperature and transverse flow velocity in central nucleus–nucleus (AA) collisions are larger than in peripheral collisions, and both of them are slightly larger in peripheral nucleus–nucleus collisions or almost equivalent to that in proton–proton collisions at the same center-of-mass energy which shows their similar thermodynamic nature.

Excited state mass spectra of the low lying single charmed baryons with nonstrangeness have been calculated in a hypercentral approach. The six-dimensional hyperradial Schrödinger equation is solved by applying a simple variational method. We extend our scheme to predict the magnetic moments and the ${\frac{3}{2}}^{+}\to {\frac{1}{2}}^{+}$ transition magnetic moments of ${\mathrm{\Sigma }}_c$ and ${\mathrm{\Lambda }}_c$ state baryons. A comparison of our results with the experimental data and predictions obtained in recent models is also presented.

The mass modifications of the open charm ($D$ and $D^{\ast }$) mesons, and their effects on the decay widths $D^{\ast }\to D\pi$ as well as of the charmonium state, $\mathrm{\Psi }(3770)$ to open charm mesons ($\mathrm{\Psi }(3770)\to D\bar{D}$), are investigated in the presence of strong magnetic fields. These are studied accounting for the mixing of the pseudoscalar ($P$) and vector ($V$) mesons ($D-D^{\ast }$, ${\eta }_c^{\prime }-\mathrm{\Psi }(3770)$ mixings), with the mixing parameter, $g_{PV}$ of a phenomenological three-point ($PV\gamma$) vertex interaction determined from the observed radiative decay width of $V\to P\gamma$. For charged $D-D^{\ast }$ mixing, this parameter is dependent on the magnetic field, because of the Landau level contributions to the vacuum masses of these mesons. The masses of the charged $D$ and $D^{\ast }$ mesons modified due to $PV$ mixing, in addition, have contributions from the lowest Landau levels in the presence of a strong magnetic field. The effects of the magnetic field on the decay widths are studied using a field theoretical model of composite hadrons with quark (and antiquark) constituents. The matrix elements for these decays are evaluated using the light quark–antiquark pair creation term of the free Dirac Hamiltonian for the constituent quark field, with explicit constructions for the charmonium state $\mathrm{\Psi }(3770)$, the open charm ($D$, $\bar{D}$, $D^{\ast }$) mesons and the pion states in terms of the constituent quark fields. The parameter for the charged $D-D^{\ast }$ mixing is observed to increase appreciably with increase in the magnetic field. This leads to dominant modifications to their masses, and hence the decay widths of charged $D^{\ast }\to D\pi$ as well as $\mathrm{\Psi }(3770)\to D^{+}{D}^{-}$ at large values of the magnetic field. The modifications of the masses and decay widths of the open and hidden charm mesons in the presence of strong magnetic fields should have observable consequences on the production of the open charm ($D$ and $D^{\ast }$) mesons as well as of the charmonium states resulting from noncentral ultra-relativistic heavy ion collision experiments.

In this paper, exact analytical expressions for the Jost solution and Jost function are derived for motion in the nuclear Manning–Rosen plus the Hulthén potential to study both the bound and scattering state observables. The proton-deuteron and alpha-carbon systems are studied to judge the merit of our approach. Our results are found in reasonable agreement with experimental data.

For temperatures $T$ ranging from a few MeV up to TeV and energy density $\rho$ up to $10^{16}$GeV/fm³, the bulk viscosity $\zeta$ is calculated in nonperturbation (up, down, strange, charm and bottom) and perturbation theories with up, down, strange, charm, bottom and top quark flavors, at vanishing baryon-chemical potential. To these calculations, results deduced from the effective QCD-like model, the Polyakov linear-sigma model (PLSM), are also integrated in. The PLSM merely comes up with essential contributions for the vacuum and thermal condensations of the gluons and the quarks (up, down, strange and charm flavors). Furthermore, the thermal contributions of the photons, neutrinos, charged leptons, electroweak particles and scalar Higgs boson are found very significant along the entire range of $T$ and $\rho$ and therefore could be well integrated in. We present the dimensionless quantity $9{\omega }_0\zeta /Ts$, where ${\omega }_0$ is a perturbative scale and $s$ is the entropy density and conclude that $9{\omega }_0\zeta /Ts$ exponentially decreases with increasing $T$. We also conclude that the resulting $\zeta$ with the nonperturbative and perturbative QCD contributions nonmonotonically increases with increasing $\rho$. But with nearly-entire standard model contributions considered in this study, $\zeta$ almost-linearly increases with increasing of $\rho$. Apparently, these results offer a great deal to explore in astrophysics, cosmology and nuclear collisions.

We have studied transverse momentum distributions of charged particles produced in pp and Pb–Pb collisions at ${\sqrt{s}}_{NN}=2.76$ TeV and 5.02 TeV in the pseudorapidity interval $\left|\eta \right|<0.8$ and transverse momentum range $0<p_T<20$GeV/$c$. We simulated data using EPOS-LHC, EPOS-1.99 and QGSJETII-04 models. The simulation data is compared with the ALICE experimental data values at ${\sqrt{s}}_{NN}=2.76$ TeV and 5.02 TeV for pp and most central Pb–Pb collisions. It has been observed that, EPOS-LHC and QGSJETII-04 models explain the experimental results for pp collision at ${\sqrt{s}}_{NN}=2.76$ TeV and 5.02 TeV. The behavior of nuclear modification factors has been studied. The simulation codes of all three models EPOS-LHC, EPOS-1.99 and QGSJETII-04 overestimate the experimental results at low transverse momentum interval: $0<p_T<6$ GeV/$c$, for Pb–Pb collisions at ${\sqrt{s}}_{NN}=2.76$ TeV and 5.02 TeV. However, only EPOS-LHC model can explain the experimental data at high transverse momentum in the range: $6<p_T<20$ GeV/$c$. EPOS-1.99 and QGSJETII-04 underestimate in the region of Cronin effect and cannot give satisfactory estimates for the $p_T$ values for which $R_{\mathrm{\text{Pb-Pb}}}$ demonstrates stronger suppression because of the collective parton effect. It can be inferred that these effects are not taken into account in EPOS-1.99 and QGSJETII-04 models. These models, however, satisfactorily explain the ALICE experimental data in the ranges of $p_T$ for which nuclear modification factor $R_{\mathrm{\text{Pb-Pb}}}$ shows rising trend.

The isospin splitting of the in-medium $NN\to N\mathrm{\Delta }$ cross-sections in asymmetric nuclear medium is investigated in the framework of the one-boson exchange model by including $\delta$ and $\rho$ mesons. Our results show that the medium correction factors $R={\sigma }_{NN\to N\mathrm{\Delta }}^{\ast }/{\sigma }_{NN\to N\mathrm{\Delta }}^{\text{free}}$ have $R_{pp\to n{\mathrm{\Delta }}^{++}}<R_{nn\to p{\mathrm{\Delta }}^{-}}$ and $R_{NN\to N{\mathrm{\Delta }}^{+}}<R_{NN\to N{\mathrm{\Delta }}^0}$ by using the without-$\delta$ sets. By including the $\delta$ meson, there appear the totally opposite results in the $R$ for different channels, i.e., $R_{pp\to n{\mathrm{\Delta }}^{++}}>R_{nn\to p{\mathrm{\Delta }}^{-}}$ and $R_{NN\to N{\mathrm{\Delta }}^{+}}>R_{NN\to N{\mathrm{\Delta }}^0}$.

In this paper, various ground state properties are explored for full isotonic(isotopic) chain of neutron number N $($proton number $Z)=40$ using different families of Relativistic Mean-Field theory. Several properties, such as nucleon separation energies, pairing energies, deformation, radii and nucleon density distributions, are evaluated and compared with the experimental data as well as those from other microscopic and macroscopic models. $N=40$ isotonic chain presents ample of support for the neutron magicity and articulates double magicity in recently discovered ${}^{60}$Ca and ${}^{68}$Ni. Our results are in close conformity with the recently measured value of charge radius of ${}^{68}$Ni [S. Kaufmann et al., Phys. Rev. Lett. 124 (2020) 132502] which supports the $N=40$ magicity. Contrarily, Zr isotopes ($Z=40$) display variety of shapes leading to the phenomenon of shape transitions and shape co-existence. The role of 3s${}_{1/2}$ state, which leads to central depletion if unoccupied, is also investigated. ${}_{16}^{56}$S and ${}_{40}^{122}$Zr are found to be doubly bubble nuclei.

In order to describe scattering, fusion, fission and ground state masses, Krappe and collaborators developed unified nuclear potential, by generalizing liquid drop model. They have incorporated phenomenological parameters accounting for the attractive force between two separated fragments. One of the phenomenological parameters involved in this model is the range of folded Yukawa function, which accounts for surface diffuseness of the potential and short range attractive interaction. The role of range of folding function of Yukawa-plus-exponential potential is analyzed for alpha decay of heavy and superheavy nuclei. Significant effect of this function is noted in preformation probability which improves the accuracy of half-lives of alpha decay. Half-lives for alpha decay are better obtained for two values of the range of folding function 0.54 and 0.8fm for heavy and superheavy mass regions, respectively. The study confirms the associated shell structure $N=126$ in heavy nuclei and $N=152,162$ and $184$ in superheavy nuclei. The calculations are extended to predict the half-lives of superheavy nuclei with $118\le Z\le 125$ and $278\le A\le 320$ which are not yet synthesized experimentally.

The particle ratios $k^{+}/{\pi }^{+}$, ${\pi }^{-}/K^{-}$, $\bar{p}/{\pi }^{-}$, $\mathrm{\Lambda }/{\pi }^{-}$, $\mathrm{\Omega }/{\pi }^{-}$, $p/{\pi }^{+}$, ${\pi }^{-}/{\pi }^{+}$, $K^{-}/K^{+}$, $\bar{p}/p$, $\bar{\mathrm{\Lambda }}/\mathrm{\Lambda }$, $\bar{\mathrm{\Sigma }}/\mathrm{\Sigma }$, $\bar{\mathrm{\Omega }}/\mathrm{\Omega }$ measured at AGS, SPS and RHIC energies are compared with large statistical ensembles of 100,000 events deduced from the CRMC EPOS $1.99$ and the Ultra-relativistic Quantum Molecular Dynamics (UrQMD) hybrid model. In the UrQMD hybrid model two types of phase transitions are taken into account. All these data are then confronted with the ideal Hadron Resonance Gas Model. The two types of phase transitions are apparently indistinguishable. Apart from $k^{+}/{\pi }^{+}$, $k^{-}/{\pi }^{-}$, $\mathrm{\Omega }/{\pi }^{-}$, $\bar{p}/{\pi }^{+}$ and $\bar{\mathrm{\Omega }}/\mathrm{\Omega }$, the UrQMD hybrid model agrees well with the CRMC EPOS $1.99$. We also conclude that the CRMC EPOS $1.99$ seems to largely underestimate $k^{+}/{\pi }^{+}$, $k^{-}/{\pi }^{-}$, $\mathrm{\Omega }/{\pi }^{-}$ and $\bar{p}/{\pi }^{+}$.

The transverse momentum distribution of charged particles formed in Au–Au collisions at Beam Energy Scan (BES) ($\sqrt{S_{NN}}=7.7,11.5,19.6,27,39$GeV) is investigated. In addition, $P_T$ spectra of $\mathrm{\Lambda }$ particle at $\sqrt{S_{NN}}=62.4$GeV were examined. Tsallis distribution is used to extract the temperature, volume and the entropic index from the experimental results at mid-rapidity and zero chemical potential. We measure some particle ratios like $\frac{k^{+}}{{\pi }^{+}}$ and $\frac{\mathrm{\Lambda }}{{\pi }^{-}}$ which are puzzling horn in the experiment and in the thermal model. We conclude that the horn vanished when we used Tsallis distribution, but this does not confirm a solution to the puzzle, which is primarily visible in the experimental results.

In this work, we systematically study the two-proton ($2p$) radioactivity half-lives of nuclei close to the proton drip line within a modified Gamow-like model. Using this model, the calculated $2p$ radioactivity half-lives can well reproduce the experimental data. Moreover, we blackuse this model to predict the $2p$ radioactivity half-lives of 22 candidates blackwhose $2p$ radioactivity is energetically allowed or observed but not yet quantized in evaluated nuclear properties table NUBASE2016. blackThe predicted results are in good agreement with the ones obtained by using Gamow-like model, effective liquid drop model (ELDM), generalized liquid drop model (GLDM) as well as a four-parameter formula.