Search

The exclusive production of axionlike particles (ALPs) by gluon -- induced interactions is investigated in this exploratory study considering $pp$ and $PbPb$ collisions for the energies of the next run of the Large Hadron Collider (LHC). Assuming the Duhram model, we estimate the associated cross sections for the rapidity ranges probed by central and forward detectors. A comparison with the predictions for the exclusive ALP production by photon -- induced interactions is presented. Our results indicate that the contribution of gluon -- induced interactions is nonnegligible and can become dominant in $pp$ collisions for small values of the ALP mass., Comment: 6 pages, 3 figures. Improved version to be published in Physics Letters B

The photoproduction of vector mesons in $pPb$ collisions at LHC energies is investigated assuming that the color singlet $t$-channel exchange carries a large momentum transfer $t$. The rapidity distributions and total cross sections for the process $Pb \, p \rightarrow Pb \otimes V \otimes \,jet + X$, with $V = \rho, \, J/\Psi$ and $\otimes$ representing a rapidity gap in the final state, are estimated considering the non-forward solution of the BFKL equation at high energy and large -- $t$. A comparison with the predictions obtained at the Born level also is presented. We predict a large enhancement of the cross sections associated to the BFKL dynamics in the kinematical range probed by the LHCb Collaboration. Moreover, our results indicate that the experimental identification can be feasible at the LHC and that this process can be used to probe the BFKL dynamics., Comment: 7 pages, 4 figures, 1 table. Improved version to be published in Physics Letters B. arXiv admin note: text overlap with arXiv:0911.5638

The exclusive production by the photon fusion of magnetic monopoles and the bound states of magnetic monopoles, the monopolium, is consider in different high energy processes. More specifically, we calculate the total cross sections of the ultraperipheral elastic collisions of electron-electron, proton-proton and lead-lead in present and future colliders, comparing with the previous results found in the literature. Our results indicates that magnetic monopoles or his bound states, if both exists, can be measuareble in future electron-electron colliders., Comment: 11 pages, 4 figures

We provide a universal expression of cross sections for the exclusive vector meson production and Deeply Virtual Compton Scattering (DVCS) in photon-proton and photon-nucleus interactions based on the geometric scaling phenomenon. The theoretical parameterization based on the scaling property depends only on the single variable $\tau_A = Q^2/Q_{\mathrm{sat}}^2$, where the saturation scale, $Q_{\mathrm{sat}}$, drives the energy dependence and the corresponding nuclear effects. This phenomenological result describes all available data from DESY-HERA for $\rho,\,\phi,\,J/\psi$ production and DVCS measurements. A discussion on the size of nuclear shadowing corrections on photon-nucleus interaction is also done., Comment: 8 pages, 3 figures and 2 tables. Extended version to be published in Physical Review D. Title has been changed

The current uncertainty on the gluon density extracted from the global parton analysis is large in the kinematical range of small values of the Bjorken - $x$ variable and low values of the hard scale $Q^2$. An alternative to reduces this uncertainty is the analysis of the exclusive vector meson photoproduction in photon - hadron and hadron - hadron collisions. This process offers a unique opportunity to constrain the gluon density of the proton, since its cross section is proportional to the gluon density squared. In this paper we consider current parametrizations for the gluon distribution and estimate the exclusive vector meson photoproduction cross section at HERA and LHC using the leading logarithmic formalism. We perform a fit of the normalization of the $\gamma h$ cross section and the value of the hard scale for the process and demonstrate that the current LHCb experimental data are better described by models that assume a slow increasing of the gluon distribution at small - $x$ and low $Q^2$., Comment: 8 pages, 6 figures, 1 table. Version published in European Physical Journal C

One of the open questions of the strong interaction theory is the existence of the Odderon, which is an unambiguous prediction of Quantum Chromodynamics, but still not confirmed experimentally. An alternative to probe the Odderon is the exclusive $\eta_c$ photoproduction in hadronic collisions. As the Pomeron exchange cannot contribute to this process, its observation would indicate the existence of the Odderon. In this paper we estimate the $\eta_c$ production in photon - induced interactions in hadronic collisions at the AFTER@LHC experiment. We demonstrate that the experimental analysis of this process is feasible in the AFTER@LHC experiment and that the observation of the $\eta_c$ production in nuclear collisions is a unambiguous signature of the Odderon., Comment: 6 pages, 2 figures, 1 table. Revised version with new references included. arXiv admin note: substantial text overlap with arXiv:1211.1207

The existence of a dilaton as a pseudo-Nambu-Goldstone boson in spontaneous breaking of scale symmetry is predicted in beyond standard model theories in which electroweak symmetry is broken via strongly coupled conformal dynamics. Such a particle is expected to have a mass below the conformal symmetry breaking scale $f$ and couplings to standard model particles similar to those of the SM Higgs boson. In this paper we estimate, for the first time, the dilaton production in exclusive processes considering Pomeron - Pomeron ($\pom \pom$) and photon - photon ($\gamma \gamma$) interactions, which are characterized by two rapidity gaps and intact hadrons in the final state. Our results indicate that if the dilaton is massive ($M_{\chi} \ge 2 M_W$), the study of dilaton production by $\pom \pom$ interactions in $pp$ collisions can be useful to determine its mass and the conformal energy scale., Comment: 7 pages, 3 figures, 1 table

In this paper we study the diffractive $Z$ boson pair production mediated by the Kaluza-Klein graviton in the large extra dimensions scenario at the CERN Large Hadron Collider energies. Considering the Durham model we estimate the total cross section for the central inclusive and exclusive diffractive production of a $Z$ boson pair in $pp/pPb/PbPb$ collisions. Our results indicate that the experimental analysis of the central inclusive production in $pp$ collisions is feasible at CERN LHC., Comment: 15 pages, 7 figures, 1 table. Published in Phys. Rev. D89, 076003 (2014)

The diffractive photon production at large momentum transfer and large energies is a probe of the parton dynamics of the diffractive exchange. In this paper we revisit the leading order (LO) BFKL equation approach for this process and estimate, for the first time, the differential and total cross sections considering the next-to-leading order (NLO) corrections for the BFKL characteristic function. We obtain a reasonable agreement with the DESY HERA data., Comment: 8 pages, 4 figures. Version published in Physical Review D

The meson production cross sections are estimated considering photon-photon interactions in hadron - hadron collisions at CERN LHC energies. We consider a large number of mesons with photon-photon partial decay width well constrained by the experiment and some mesons which are currently considered as hadronic molecule and glueball candidates. Our results demonstrate that the experimental analysis of these states is feasible at CERN - LHC., Comment: 5 pages, 1 figure, 4 tables. Version published in Physical Review C

In the Randall-Sundrum (RS) scenario the compactification radius of the extra dimension is stabilized by the radion, which is a scalar field lighter than the graviton Kaluza-Klein states. It implies that the detection of the radion will be the first signature of the stabilized RS model. In this paper we study the exclusive production of the radion in electromagnetic and diffractive hadron - hadron collisions at the LHC. Our results demonstrate that the diffractive production of radion is dominant and should be feasible of study at CERN LHC., Comment: 6 pages, 3 figures, 1 table

The diffractive vector meson photoproduction with hadron dissociation in coherent hadron-hadron interactions at LHC energies is studied assuming that the color singlet $t$-channel exchange carries large momentum transfer. We estimate the rapidity distribution and total cross section for the processes $pp \rightarrow p V X$ and $PbPb \rightarrow Pb V X$ ($V = \rho$ or $\Upsilon$) considering the non-forward solution of the BFKL equation at high energy and large momentum transfer. Our results indicate that the experimental identification of these processes can be feasible at the LHC., Comment: 11 pages, 3 figures, 1 table. Version to be published in European Physical Journal A

The vector meson production in coherent hadron-hadron interactions at LHC energies is studied assuming that the color singlet $t$-channel exchange carries large momentum transfer. We consider the non-forward solution of the BFKL equation at high energy and large momentum transfer and estimate the rapidity distribution and total cross section for the process $h_1 h_2 \to h_1 J/\Psi X$, where $h_i$ can be a proton or a nucleus. We predict large rates, which implies that the experimental identification can be feasible at the LHC., Comment: 10 pages, 5 figures, 1 table. Version to be published in Physical Review D

In this paper the two-photon interactions at high energies are investigated considering different approaches for the QCD dynamics. In particular, we calculate the $\gamma^* \gamma^*$ total cross section in different theoretical approches and present a comparison among the predictions of the BFKL dynamics at leading and next-to-leading order with those from saturation physics. We analyze the possibility that the future linear colliders could discriminate between these different approaches., Comment: 14 pages, 2 figures. Version to be published in Journal of Physics G: Nuclear and Particle Physics

In this work, we perform a comparison of the employ of distinct gluon propagators with the experimental data in diffractive processes, $pp$ elastic scattering and light meson photo-production. The gluon propagators are calculated through non-perturbative methods, being justified their use in this class of events, due to the smallness of the momentum transfer. Our results are not able to select the best choice for the modified gluon propagator among the analyzed ones, showing that the application of this procedure in this class of high energy processes, although giving a reasonable fit to the experimental data, should be taken with same caution., Comment: 14 pages, 4 figures, accepted for publication in Int. J. Mod. Phys. A (uses ws-ijmpa.cls). Authors corrected

In this Letter we study the double diffractive vector meson production in $e^+e^-$ collisions assuming the dominance of the BFKL pomeron exchange. We consider the non-forward solution of the BFKL equation at high energy and large momentum transfer and estimate the total cross section for the process $e^+e^- \to e^+e^- V_1 V_2$ with antitagged $e^+$ and $e^-$, where $V_1$ and $V_2$ can be any two vector mesons ($V_i = \rho, \omega, \phi, J/\Psi, \Upsilon$). The event rates for the future linear colliders are given., Comment: 8 pages, 1 figure, Version to be published in Physical Review D

In this work the double vector meson production in ultraperipheral heavy ion collisions is investigated within the BFKL approach. The integrated cross sections and event rates for the processes AA --> V1 V2 AA (V_i = rho, omega, phi, J/Psi, Upsilon) are computed and theoretical estimates for scattering on both light and heavy nuclei are given for energies of RHIC and LHC., Comment: 10 pages, 1 figure. Version to be published in the European Physical Journal C

The double vector meson production in two photon collisions is addressed assuming that the color singlet $t$-channel exchange carries large momentum transfer. We consider the non-forward solution of the BFKL equation at high energy and large momentum transfer and estimate the total and differential cross section for the process $\gamma \gamma \to V_1 V_2$, where $V_1$ and $V_2$ can be any two vector mesons ($V_i = \rho, \omega, \phi, J/\Psi, \Upsilon$). A comparison between our predictions and previous theoretical results obtained at Born level or assuming the Pomeron-exchange factorization relations is presented. Our results demonstrate that the BFKL dynamics implies an enhancement of the cross sections. Predictions for the future linear colliders (TESLA, CLIC and ILC) are given., Comment: 13 pages, 3 tables, 7 figures. Minor changes. Accepted for publication in Eur. Phys. J. C

The application of a modified gluon propagator and an infrared frozen running co upling constant in the description of the proton-proton elastic scattering is in vestigated. The model based on the exchange of the Pomeron as a pair of non-pert urbative gluons is modified to include the frozen coupling constant in the infra red kinematic region. A good fit to the data of the differential cross section f or different center of mass energies (53 GeV and 1.8 TeV) is obtained., Comment: REVTEX, 13 pages, 4 figures

The meson (pion and kaon) form factor is calculated in the perturbative framework with alternative forms for the running coupling constant and the gluon propagator in the infrared kinematic region. These modified forms are employed to test the sensibility of the meson form factor to the nonperturbative contributions. Its is a powerful discriminating quantity and the results obtained with a particular choice of modified running coupling constant and gluon propagator have a good agreement with the available data, for both mesons, indicating the robustness of the method of calculation. Nevertheless, nonperturbative aspects may be included in the perturbative framework of calculation of exclusive processes., Comment: 18 pages, 7 figures. Discutions added, clarifing figures. Accepted to be published in Phys. Rev. D