Search

In this paper we investigate the impact of the higher - twist effects, resummed by the non - linear approaches for the QCD dynamics, on the inclusive observables that will be measured in future electron - ion colliders. We assume a phenomenological model for the dipole - nucleus scattering amplitude which takes into account the non - linear corrections and estimate the contribution of the different twists for $F_2^A(x,Q^2)$, $F_L^A(x,Q^2)$ and $\partial F_2^A /\partial ln Q^2$ considering different values of the Bjorken - $x$ variable, photon virtuality $Q^2$ and atomic number $A$. A comparison with the full predictions is performed and the impact of the distinct twists is estimated. Our results indicate that a future analysis of the logarithmic $Q^2$ slope and longitudinal structure function will allow us to probe the presence of the non - linear effects on the QCD dynamics., Comment: 9 pages, 6 figures. Improved version published in EPJA

One of the main goals of future electron-ion colliders is to improve our understanding of the structure of hadrons. In this letter, we study the exclusive $η_c$ production by $γ^{*} γ$ interactions in $eA$ collisions and demonstrate that future experimental analysis of this process can be used to improve the description of the $η_c$ transition form factor. The rapidity, transverse momentum and photon virtuality distributions are estimated considering the energy and target configurations expected to be present at the EIC, EicC and LHeC and assuming different predictions for the light-front wave function of the $η_c$ meson. Our results indicate that the electron-ion colliders can be considered an alternative to providing supplementary data to those obtained in $e^- e^+$ colliders., 11 pages, 5 figures

The production of isolated photons in high multiplicity events is investigated considering the Color Glass Condensate (CGC) formalism. The associated cross section for proton - proton collisions is estimated considering three distinct solutions of the Balitsky - Kovchegov (BK) equation and predictions for the normalized photon yield as a function of the multiplicities of co - produced charged particles are presented. We predict the increasing of the yield with the multiplicity, with the slope being smaller for larger rapidities. As the isolated photon production is not affected by the fragmentation process, a future experimental investigation of this process in current high energy hadronic colliders is ideal to test the treatment of high multiplicity events using the CGC formalism, previously applied only for the production of hadronic final states., Comment: 6 pages, 3 figures

The dynamical stability of strange-dwarf hybrid stars and strange planets, constituted by strange-quark-matter cores and dilute-nuclear-matter crusts, is revisited by analyzing the fundamental mode eigenfrequencies of the radial oscillation equations with boundary conditions for slow (rapid) conversions originating at the density-discontinuous interface characterizing {extremely large (small) microscopic timescales compared to the oscillation periods}. For the hadronic crust we used an analytic fit of the BPS results matched to the massless MIT bag model. For the rapid case, our calculations indicate that the zero mode is the so-called {\it reaction mode} which is a complex number, thus ruling out the existence of strange dwarfs (planets) in nature. On the other hand, slow conversions {still provide a sizeable stability window which, interestingly, also reproduces the} Glendenning-Kettner-Weber {results}. The robustness of our findings is demonstrated for different transition densities and using an equation of state from perturbative QCD for the ultra-dense core., Comment: 7 pages, 3 figures. v2: 1 page added, 3 figures replaced; Secs. I-II-IV and acknowledgements partly rewritten; Sec. III completely rewritten in order to include the response to discussions with authors of past works; Tabulated BPS EoS replaced by a fit formula; Added brief discussion of differences with version v1

We outline the physics opportunities provided by the Electron Ion Collider (EIC). These include the study of the parton structure of the nucleon and nuclei, the onset of gluon saturation, the production of jets and heavy flavor, hadron spectroscopy and tests of fundamental symmetries. We review the present status and future challenges in EIC theory that have to be addressed in order to realize this ambitious and impactful physics program, including how to engage a diverse and inclusive workforce. In order to address these many-fold challenges, we propose a coordinated effort involving theory groups with differing expertise is needed. We discuss the scientific goals and scope of such an EIC Theory Alliance., Comment: 44 pages, ReVTeX, White Paper on EIC Theory Alliance

The study of exclusive processes in ultraperipheral collisions at the Large Hadron Collider (LHC) has allowed us to test several aspects of the Standard Model and to search for New Physics. In this letter, we investigate the possibility of using these processes to improve our understanding of the quarkonium production mechanism through the study of the exclusive $J/Ψ$ plus jet associate production in ultraperipheral $PbPb$ collisions. We estimate the transverse - momentum and rapidity distributions considering that the $γγ\rightarrow J/Ψ+ X$ ($X = γ, \, g$) subprocess is described by the Non - Relativistic QCD (NRQCD) formalism and present predictions for the rapidity ranges covered by central and forward detectors. The experimental separation of these events is discussed and the results indicate that a future experimental analysis is, in principle, feasible in future runs of the LHC and the Future Circular Collider (FCC)., 9 pages, 4 figures, 2 tables

In this paper we analyze the associated production of a vector meson with a (pseudo)scalar bound state or a dimuon system in ultraperipheral $PbPb$ collisions through the double scattering mechanism for the energies of the Large Hadron Collider (LHC) and Future Circular Collider (FCC). Our results complement previous studies for the double vector meson production. We present our predictions for the total cross sections and rapidity distributions considering the rapidity ranges covered by the ALICE and LHCb detectors, which indicate that a future experimental analysis of the $\phi + \eta_c$, $\phi + \mu^+ \mu^-$ and $J/\Psi + \mu^+ \mu^-$ final states is feasible., Comment: 6 pages, 2 figures, 1 table. arXiv admin note: text overlap with arXiv:2210.04861

The production of the $K_S^0$ meson in high multiplicity $pp$ collisions at $\sqrt{s} =$ 13 TeV is investigated considering the hybrid formalism and the solution of the running coupling Balitsky - Kovchegov equation. The associated cross section is estimated and compared with the experimental data for the transverse momentum spectrum. Moreover, we analyze the self-normalized yields of $K_S^0$ mesons as a function of the multiplicity of coproduced charged hadrons and demonstrate that a steep increasing is theoretically predicted. A comparison with the ALICE data is presented considering two distinct solutions of the BK equation., Comment: 8 pages, 5 figures. Improved version to be published in Physical Review C

Collisions with Oxygen ions at the LHC opens the possibility of investigating the description of the QCD dynamics in an unexplored regime, complementary to those performed in $pp$, $pPb$ and $PbPb$ collisions. In this paper we estimate the exclusive $ρ$ and $J/Ψ$ photoproduction in ultraperipheral $pO$ and $OO$ collisions at the Large Hadron Collider using the color dipole formalism and considering distinct models for the dipole - target scattering amplitude and different approaches for the modelling of the vector meson wave function. We present our predictions for the rapidity and transverse momentum distributions, as well as for the total cross sections considering the rapidity ranges covered by the ALICE and LHCb detectors. Such results indicate that a future experimental analysis of these final states is feasible and that its study can be useful to improve our understanding of the QCD dynamics at high energies., 11 pages, 7 figures, 2 tables. Improved and enlarged version to be published in Physical Review C

In this paper we analyze the associated $ϕ$ and $J/Ψ$ photoproduction in ultraperipheral $PbPb$ collisions through the double scattering mechanism for the energies of the Large Hadron Collider (LHC) and Future Circular Collider (FCC). Our results complement a previous analysis for the $ρρ$, $J/ΨJ/Ψ$ and $ρJ/Ψ$ production. We present our predictions for the total cross sections and rapidity distributions considering the rapidity ranges covered by the ALICE and LHCb detectors, which indicate that a future experimental analysis of $ϕJ/Ψ$ final state is feasible. These results point out that the study of the double vector meson photoproduction in heavy ion collisions can be useful to constrain the double scattering mechanism and improve our understanding of the QCD dynamics at high energies., 7 pages, 3 figures, 1 table. Improved version published in EPJA

We investigate the production of the fully - heavy tetraquark states $T_{4Q}$ in the $����$ interactions present in proton-proton, proton-nucleus and nucleus-nucleus collisions at the CERN Large Hadron Collider (LHC). We focus on the $����\rightarrow {\cal{Q}}{\cal{Q}}$ (${\cal{Q}} = J/��,\, ��$) subprocess, mediated by the $T_{4Q}$ resonance in the $s$ - channel, and present predictions for the hadronic cross sections considering the kinematical ranges probed by the ALICE and LHCb Collaborations. Our results demonstrate that the experimental study of this process is feasible and can be used to investigate the existence and properties of the $T_{4c}(6900)$ and $T_{4b}(19000)$ states., 5 pages, 2 figures, 2 tables. arXiv admin note: substantial text overlap with arXiv:1809.08125

The predictions for the atmospheric neutrino flux at high energies strongly depend on the contribution of prompt neutrinos, which are determined by the production of charmed meson in the atmosphere at very forward rapidities. In this paper we estimate the related cross sections taking into account the presence of an intrinsic charm (IC) component in the proton wave function and the QCD dynamics modified by the onset of saturation effects. The impact on the predictions for the prompt neutrino flux is investigated assuming different values for the probability to find the IC in the nucleon. Comparison with the IceCube data is performed and conclusions are drawn., 15 pages, 8 figures

The coherent and incoherent $J/��$ photoproduction in $PbPb$ collisions are investigated considering the possible states of nucleon configurations in the nuclear wave function and taking into account of the non - linear corrections to the QCD dynamics. The cross sections and the rapidity and transverse momentum distributions are estimated for the energies of the next run of the LHC, High -- Energy LHC and Future Circular Collider. Our results indicate that a future experimental analysis of these processes will be useful to discriminate between different approaches for the QCD dynamics as well to improve our description of the gluon saturation effects., 7 pages, 3 figures, 1 table

In this paper we describe the evolution of the Universe in terms of the Friedmann equation, which takes into account of the composition and geometry of the Universe. The dependence of the solution on the geometry and composition for different combinations of the basic constituents are discussed. The distinct behaviors for the temporal evolution of the Universe are determined and the scenario predicted by the Standard Cosmology is presented., Comment: 23 pages, 8 figures. Text in Portuguese. Published in Revista Brasileira de Ensino de Fisica

We derive the light-front wave function (LFWF) representation of the $��^* ��^* \to ��_c(1S)\,,��_c(2S)$ transition form factor $F(Q_1^2, Q_2^2)$ for two virtual photons in the initial state. For the LFWF, we use different models obtained from the solution of the Schr��dinger equation for a variety of $c \bar c$ potentials. We compare our results to the BaBar experimental data for the $��_c(1S)$ transition form factor, for one real and one virtual photon. We observe that the onset of the asymptotic behaviour is strongly delayed and discuss applicability of the collinear and/or massless limit. We present some examples of two-dimensional distributions for $F (Q_1^2,Q_2^2)$. A factorization breaking measure is proposed and factorization breaking effects are quantified and shown to be almost model independent. Factorization is shown to be strongly broken, and a scaling of the form factor as a function of $\bar Q^2 = (Q_1^2 + Q_2^2)/2$ is obtained., 22 pages, 9 figs

The description of the heavy meson production at large energies and forward rapidities at the LHC is fundamental to derive realistic predictions of the prompt atmospheric neutrino flux at the IceCube Observatory. In particular, the prompt tau neutrino flux is determined by the decay of $D_s$ mesons produced in cosmic ray - air interactions at high energies and large values of the Feynman - $x_F$ variable. Recent data from the LHCb Collaboration indicate a production asymmetry for $D_s^+$ and $D_s^-$ mesons, which cannot be explained in terms of the standard modelling of the hadronization process. In this paper we demonstrate that this asymmetry can be described assuming an asymmetric strange sea ($s(x) \ne \bar s(x)$) in the proton wave function and taking into account of the charm and strange fragmentation into $D_s$ mesons. Moreover, we show that the strange quark fragmentation contribution is dominant at large - $x_F$ ($\ge 0.3$). The prompt $��_��$ flux is calculated and the enhancement associated to the strange quark fragmentation contribution, disregarded in previous calculations, is estimated., 6 pages, 3 figures

We present a detailed mapping of the dominant kinematical domains contributing to the prompt atmospheric neutrino flux at high neutrino energies by studying its sensitivity to the cuts on several kinematical variables crucial for charm production in cosmic ray scattering in the atmosphere. This includes the maximal center-of-mass energy for proton-proton scattering, the longitudinal momentum fractions of partons in the projectile (cosmic ray) and target (nucleus of the atmosphere), the Feynman $x_F$ variable and the transverse momentum of charm quark/antiquark. We find that the production of neutrinos with energies larger than $E_{\nu} >$ 10$^7$ GeV is particularly sensitive to the center-of-mass energies larger than the ones at the LHC and to the longitudinal momentum fractions in the projectile 10$^{-8}$ $< x, Comment: 11 pages, 9 figures

The parasite Plasmodium vivax is the most widely distributed cause of recurring malaria. N-Myristoyltransferase (NMT), an enzyme that catalyses the covalent attachment of myristate to the N-terminal glycine of substrate proteins, has been described as a potential target for the treatment of this disease. Herein, we report the synthesis and the structure-guided optimization of a series of quinolines with balanced activity against both Plasmodium vivax and Plasmodium falciparum N-myristoyltransferase (NMT).

In this work, we investigate production of Drell-Yan (DY) pairs in proton-nucleus collisions in kinematic regions where the corresponding coherence length does not exceed the nuclear radius, $R_A$, and the quantum coherence effects should be treated with a special care. The results for the nucleus-to-nucleon production ratio available in the literature so far are usually based on the assumption of a very long coherence length (LCL) $l_c\gg R_A$. Since the onset of coherence effects is controlled by the coherence length $l_c$, we estimated its magnitude in various kinematic regions of the DY process and found that the LCL approximation should not be used at small and medium c.m. collision energies ($\sqrt{s} \lesssim 200$ GeV) as well as at large dilepton invariant masses. In order to obtain realistic predictions, we computed for the first time the DY cross section using the generalised color dipole approach based on the rigorous Green function formalism, which naturally incorporates the color transparency and quantum coherence effects and hence allows to estimate the nuclear shadowing with no restrictions on the CL. In addition to the shadowing effect, we studied a complementary effect of initial state interactions (ISI) that causes an additional suppression at large values of the Feynman variable. Numerical results for the nuclear modification factor accounting for the ISI effect and the finite $l_c$ are compared to the data available from the fixed-target FNAL measurements and a good agreement has been found. Besides, we present new predictions for the nuclear suppression as a function of dilepton rapidity and invariant mass in the kinematic regions that can be probed by the RHIC collider as well as by the planned AFTER@LHC and LHCb fixed-target experiments., Comment: 14 pages, 10 figures

In this work we obtain the DLLA limit of BFKL in the dipole picture and compare it with HERA data. We demonstrate that in leading-logarithmic- approximation, where $\alpha_s$ is fixed, a transition between the BFKL dynamics and the DLLA limit can be obtained in the region of $Q^2 \approx 150 GeV^2$. We compare this result with the DLLA predictions obtained with $\alpha_s$ running. In this case a transition is obtained at low $Q^2$ $(\le 5 GeV^2)$. This demonstrates the importance of the next-to-leading order corrections to the BFKL dynamics. Our conclusion is that the $F_2$ structure function is not the best observable for the determination of the dynamics, since there is great freedom in the choice of the parameters used in both BFKL and DLLA predictions., Comment: 14 pages, 2 figures, Accepted for publication in Phys. Lett. B