An exploratory study of the exclusive toponium production in pp, pPb, and PbPb collisions at the center-of-mass energies of the Large Hadron Collider (LHC) and Future Circular Collider (FCC) is performed. Assuming that the toponium is a pseudoscalar tt state, we consider its exclusive production by photon and gluon-induced interactions. Results for the total cross sections and associated rapidity distributions are presented, and the number of events at the LHC and FCC are estimated.

The impact of Lorentz violating (LV) terms on the exclusive e+e- production in ultraperipheral heavy-ion collisions at the Large Hadron Collider (LHC) is investigated, considering vectorial and axial couplings. Results for the differential and total cross sections are presented, and the sensitivity to a purely timelike coupling is estimated. Our results indicate that this process can improve the current upper bounds on the LV terms.

Opportunities for searches for axionlike particles (ALPs) coupling to photons in e(+)e(-) collisions at the Future Circular Collider (FCC-ee) and International Linear Collider (ILC) are investigated. We perform a study of the photon-fusion production of ALPs decaying into two photons, e(+)e(-)->(pi)e(+)a(gamma gamma)e(-), over the light-by-light continuum background, for the planned FCC-ee and ILC center-of-mass energies and integrated luminosities. An analysis of the feasibility measurements is presented using parametrized simulations for two types of detectors. Upper limits at 95% confidence level (C.L.) on the cross section for ALP production, sigma(gamma gamma -> a ->gamma gamma), and on the ALP-photon coupling are obtained over the m(a)approximate to 0.1-1000 GeV ALP mass range, and compared to current and future collider searches. Production cross sections down to sigma(gamma gamma -> a ->gamma gamma)approximate to 1 fb (1 ab) will be probed at m(a)approximate to 1 (300) GeV, corresponding to constraints on the axion-photon coupling as low as g(a gamma gamma )approximate to 2 x 10(-3) TeV-1.

This proposal outlines the future plans of the Brazilian High-Energy Physics (HEP) community for upcoming collider experiments. With the construction of new particle colliders on the horizon and the ongoing operation of the High-Luminosity LHC, several research groups in Brazil have put forward technical proposals, covering both hardware and software contributions, as part of the Brazilian contribution to the global effort. The primary goal remains to foster a unified effort within the Brazilian HEP community, optimizing resources and expertise to deliver a high-impact contribution to the international HEP community.

AbstractThe production of a single charged Higgs boson pair by photon–photon interactions in pp collisions at the LHC is investigated in this exploratory study. We focus on the exclusive production, which is characterized by intact protons and two-rapidity gaps in the final state, and assume the type-I two-Higgs-doublet model, which still allows a light charged Higgs. Assuming the leptonic $$H^{\pm }\rightarrow [\tau \nu _{\tau }]$$ H ± → [ τ ν τ ] decay mode, we derive predictions for the transverse momentum, rapidity and invariant mass distributions of the $$\tau ^+ \tau ^-$$ τ + τ - pair for different values of the charged Higgs mass. The contributions of different background processes are also estimated. Our results indicate that the contribution of the exclusive $$H^+ H^-$$ H + H - production for the $$[\tau ^{+}\nu _{\tau }][\tau ^{-} \nu _{\tau }]$$ [ τ + ν τ ] [ τ - ν τ ] final state is non-negligible and can, in principle, be used to searching for a light charged Higgs.

The description of the structure of proton is fundamental in order to describe the standard model processes at the LHC as well as for the searching of New Physics. Quantum fluctuations imply the presence of photons and leptons inside the proton, which admit a parton distribution function (PDF). Although the lepton PDFs are expected to be small, its presence opens new production mechanisms. In order to explore the lepton - induced processes at the LHC, a precise determination of the leptonic content of the proton is needed. In this paper we propose to constrain the content of charged leptons inside the proton through the study of the QED Compton scattering in ultraperipheral proton - nucleus collisions at the LHC. We estimate the total cross sections and associated distributions considering different models for the lepton PDFs and distinct lepton flavours. We demonstrate that a future experimental analysis of this process is feasible and that it can be used to constrain the content of electrons, muons and taus inside the proton.

The type II seesaw model predicts the existence of a doubly charged Higgs boson ($H ^{\pm\pm}$), which can be produced through the Drell - Yan process and photon -- induced interactions at hadronic colliders. In recent years, such reactions have been largely investigated in inclusive processes, where both incident protons breakup and a large number of particles is produced in addition to the doubly charged Higgs pair. In this paper, we investigate, for the first time, the possibility of searching for $H ^{\pm\pm}$ in exclusive processes, which are characterized by two rapidity gaps and two intact very forward protons in final state. We estimate the associated cross section making use of the exclusive nature of the final state, together with the use of timing information provided by forward proton detectors. Moreover, the background is estimated considering distinct amounts of pile-up. Our results indicate that the exclusive doubly charged Higgs pair production is a promising way to search for signatures of the type II seesaw and to obtain lower mass bounds on $H ^{\pm\pm}$.

The azimuthal correlation, Δϕ _12 , of high transverse momentum jets in pp collisions at √(s)=13 TeV is studied by applying PB-TMD distributions to NLO calculations via MCatNLO together with the PB-TMD parton shower. A very good description of the cross section as a function of Δϕ _12 is observed. In the back-to-back region of Δϕ _12→π , a very good agreement is observed with the PB-TMD Set 2 distributions while significant deviations are obtained with the PB-TMD Set 1 distributions. Set 1 uses the evolution scale while Set 2 uses transverse momentum as an argument in α _s , and the above observation therefore confirms the importance of an appropriate soft-gluon coupling in angular ordered parton evolution. The total uncertainties of the predictions are dominated by the scale uncertainties of the matrix element, while the uncertainties coming from the PB-TMDs and the corresponding PB-TMD shower are very small. The Δϕ _12 measurements are also compared with predictions using MCatNLO together Pythia 8, illustrating the importance of details of the parton shower evolution.

The exclusive vector meson production in electron - ion collisions for the energies of the future colliders is 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 results for the coherent and incoherent φ and J/ψ production in eAu collisions indicate that a future experimental analysis of these processes can be useful to constrain the description of the QCD dynamics at high energies.

In this paper we investigate the deeply virtual Compton scattering (DVCS) process in electron–ion collisions at the Electron–Ion Collider (EIC) and Large Hadron Electron Collider (LHeC). The coherent and incoherent DVCS cross sections and differential distributions are estimated considering the possible states of nucleon configurations in the nuclear wave function and taking into account of the nonlinear corrections to the QCD dynamics. The impact of the nonlinear (saturation) effects is estimated. Our results indicate that a future experimental analysis of these processes can shed light on the description of the QCD dynamics at high energies.

The elastic production of top quark pairs in $pp$ collisions at low and high luminosity regimes is investigated in detail. We extend the study performed in Phys. Rev. D102, 074014 (2020) which has demonstrated that the sum of two semi-exclusive $t\bar{t}$ production modes, namely in photon-Pomeron and Pomeron-Pomeron interactions, can be experimentally measured when the $t\bar{t}$ system decays semi-leptonically, $t\bar{t}\rightarrow jjbl\nu_l\bar{b}$, both forward protons are tagged and a low amount of pile-up is present. In this study we focus on separating individual channels and a special attention is paid to the situation at high-luminosity LHC environment. We observe that the separation of the pomeron-pomeron and photon-photon events is a challenging task, especially at high amounts of pile-up even with an optimistic 10~ps resolution of timing detectors. In contrast, the photon-Pomeron signal is relatively well separable from all backgrounds at low levels of pile-up, allowing us to discover the elastic $t\bar{t}$ production and probe, for the first time, the production of a top quark pair in the photon-Pomeron interactions. The diffractive photoproduction of such a complex system as the $t\bar{t}$ pair hence can be used not only to study diffractive properties of the scattering amplitude but also to search for new physics beyond the Standard Model, and consequently to be a solid part of the physics programme of forward proton detectors at LHC.

Abstract The dilepton production at forward rapidities in diffractive and exclusive processes present in ultraperipheral PbPb collisions at the LHC is investigated. Predictions for the $$e^+ e^-$$ e + e - , $$\mu ^+ \mu ^-$$ μ + μ - and $$\tau ^+ \tau ^-$$ τ + τ - cross sections are presented taking into account of realistic cuts that can be implemented by the LHCb Collaboration in a future experimental analysis. Our results indicate that the background associated with the diffractive production can be strongly suppressed and the exclusive processes can be cleanly separated. For the $$\tau ^+ \tau ^-$$ τ + τ - production, the semi and purely leptonic decay channels are considered. Our results indicate that a future experimental analysis of the dilepton production at the LHCb is feasible and can be useful to search for BSM physics.

The coherent and incoherent $$J/\Psi $$ photoproduction in $$Pb - Pb$$ collisions are investigated by considering the possible states of nucleon configurations in the nuclear wave function and of the non-linear corrections to the QCD dynamics. The cross sections and the differential rapidity and transverse momentum distributions are estimated for the energies of the future runs 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.

We analyze the LHC prospects for measurements of the t ($t) over bar pair produced exclusively in photon-photon or semiexclusively in photon-Pomeron and Pomeron-Pomeron processes using protons tagged in forward proton detectors on both sides of the interaction point. These processes are interesting from the point of view of a possible measurement of the top quark mass and constraining models used in beyond the Standard Model physics. Focusing on the semileptonic channel, t ($t) over bar -> jjbl nu(l)(b) over bar, making use of the exclusive nature of the final state, together with the use of timing information provided by forward proton detectors, relevant exclusive and inclusive backgrounds are studied in detail for different luminosity (or pileup) scenarios and found to be important for further consideration. While good prospects are found for observing the signal, the top quark mass measurement turns out not to be competitive with measurements in inclusive channels.

Ultra-peripheral collisions (UPCs) involving heavy ions and protons are the energy frontier for photon-mediated interactions. UPC photons can be used for many purposes, including probing low-$x$ gluons via photoproduction of dijets and vector mesons, probes of beyond-standard-model processes, such as those enabled by light-by-light scattering, and studies of two-photon production of the Higgs.

The exclusive vector meson production in electron – ion collisions for the energies of the future colliders is investigated. We present predictions for the coherent and incoherent ϕ and J/ψ production in eAu collisions 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 transverse momentum distributions are estimated assuming the energies of the Electron - Ion Collider (EIC), Large Hadron Electron Collider (LHeC) and Future Circular Collider (FCC – eh). Our results indicate that a future experimental analysis of these processes can shed light on the modeling of the gluon saturation effects and constrain the description of the QCD dynamics at high energies.

In this letter we estimate the contribution of the double diffractive processes for the diphoton production in pp collisions at the large hadron collider (LHC). The acceptance of the central and forward LHC detectors is taken into account and predictions for the invariant mass, rapidity and, transverse momentum distributions are presented. A comparison with the predictions for the light-by-light (LbL) scattering and exclusive diphoton production is performed. We demonstrate that the events associated to double diffractive processes can be separated and its study can be used to constrain the behavior of the diffractive parton distribution functions.

The production of axionlike particles (ALP) in ultraperipheral PbPb collisions (UPHIC) is investigated considering the energies of the next run of the Large Hadron Collider (LHC) and of the future High Energy–LHC (HE–LHC) and Future Circular Collider (FCC). Assuming four different combinations for the ALP mass and coupling and the typical exclusivity cuts for central and forward detectors, we estimate the cross section and invariant mass, rapidity, transverse momentum and acoplanarity distributions associated to the diphoton final state produced in the γγ→a→γγ subprocesses. A detailed analysis of the backgrounds is performed. We demonstrate that the backgrounds can be strongly reduced by the exclusivity cuts and that a forward detector, as the LHCb, is ideal to probe an ALP with small mass. Finally, our results indicate that a future experimental analysis of the diphoton final state in UPHIC can probe the existence and properties of axionlike particles.

The production of the Higgs boson in photon-photon interactions with proton and nucleus beams at three planned or proposed future CERN colliders-the high-luminosity Large Hadron Collider (HL-LHC), the high-energy LHC (HE-LHC), and the Future Circular Collider (FCC)-is studied. The cross sections for the process AA ->(gamma gamma)(A)H(A), with the ions A surviving the interaction and the Higgs scalar exclusively produced, are computed with MADGRAPH 5 modified to include the corresponding elastic gamma fluxes, for Pb-Pb, Xe-Xe, Kr-Kr, Ar-Ar, O-O, p-Pb, and p-p over the nucleon-nucleon collision energy range root s(NN) approximate to 3-100 TeV. Simulations of the gamma gamma -> H -> b (b) over bar decay mode-including realistic (mis)tagging and reconstruction efficiencies for the final-state b-jets, as well as appropriate kinematical selection criteria to reduce the similarly computed gamma gamma -> b (b) over bar, c (c) over bar, q (q) over bar continuum backgrounds-have been carried out. Taking into account the expected luminosities for all systems, the yields, and significances for observing the Higgs boson in ultraperipheral collisions (UPCs) are estimated. At the HL-LHC and HE-LHC, the colliding systems with larger Higgs significance are Ar-Ar (6.3 TeV) and Kr-Kr (12.5 TeV), respectively, but 3 sigma evidence for two-photon Higgs production would require 200 and 30 times larger integrated luminosities than those planned today at both machines. Factors of 10 can be gained by running for a year, rather than the typical 1-month heavy-ion LHC operation, but the process will likely remain unobserved until a higher energy hadron collider, such as the FCC, is built. In the latter machine, the 5 sigma observation of Higgs production in UPCs is feasible in just the first nominal run of Pb-Pb and p-Pb collisions at root s(NN) = 39 and 63 TeV, respectively.

In this paper we present a detailed analysis of the contribution of the Light-by-Light (LbL), Durham and double diffractive processes for the diphoton production in ultraperipheral PbPb collisions at the Large Hadron Collider (LHC), High-Energy LHC (HE-LHC) and Future Circular Collider (FCC). The acceptance of the central and forward LHC detectors is taken into account and predictions for the invariant mass, rapidity, transverse momentum and acoplanarity distributions are presented. Our results indicate that the contribution of the Durham process is negligible and that the double diffractive process can be strongly suppressed by the exclusivity cuts, which will allow to perform a precise analysis of the LbL scattering, as well the search of beyond Standard Model physics in this final state.