This writeup is a compilation of the predictions for the forthcoming Heavy Ion Program at the Large Hadron Collider, as presented at the CERN Theory Institute ‘Heavy Ion Collisions at the LHC—Last Call for Predictions’, held from 14th May to 10th June 2007.

The photonuclear production of vector mesons in ultraperipheral heavy ion collisions is investigated within the QCD color dipole picture, with particular emphasis on the saturation model. The integrated cross section and the rapidity distribution for the AA → V AA (V = ρ, ω, φ, J/Ψ) process are computed and theoretical estimates for scattering on both light and heavy nuclei are given for energies of RHIC and LHC. A comparison with the recent STAR data on coherent production of ρ mesons is also presented. Furthermore, we calculate the photoproduction of vector mesons in proton-proton collisions at RHIC, Tevatron and LHC energies.Recently, the STAR Collaboration released the first data on the cross section of the coherent ρ production in gold -gold ultraperipheral collisions at √ s = 130 GeV [27], providing the first opportunity to check the basic features and main approximations of the distinct approaches describing nuclear vector meson photoproduction. The main aspect is that real photons have

The Large Hadron–Electron Collider (LHeC) is designed to move the field of deep inelastic scattering (DIS) to the energy and intensity frontier of particle physics. Exploiting energy-recovery technology, it collides a novel, intense electron beam with a proton or ion beam from the High-Luminosity Large Hadron Collider (HL-LHC). The accelerator and interaction region are designed for concurrent electron–proton and proton–proton operations. This report represents an update to the LHeC’s conceptual design report (CDR), published in 2012. It comprises new results on the parton structure of the proton and heavier nuclei, QCD dynamics, and electroweak and top-quark physics. It is shown how the LHeC will open a new chapter of nuclear particle physics by extending the accessible kinematic range of lepton–nucleus scattering by several orders of magnitude. Due to its enhanced luminosity and large energy and the cleanliness of the final hadronic states, the LHeC has a strong Higgs physics programme and its own discovery potential for new physics. Building on the 2012 CDR, this report contains a detailed updated design for the energy-recovery electron linac (ERL), including a new lattice, magnet and superconducting radio-frequency technology, and further components. Challenges of energy recovery are described, and the lower-energy, high-current, three-turn ERL facility, PERLE at Orsay, is presented, which uses the LHeC characteristics serving as a development facility for the design and operation of the LHeC. An updated detector design is presented corresponding to the acceptance, resolution, and calibration goals that arise from the Higgs and parton-density-function physics programmes. This paper also presents novel results for the Future Circular Collider in electron–hadron (FCC-eh) mode, which utilises the same ERL technology to further extend the reach of DIS to even higher centre-of-mass energies.

We calculate the photonuclear production of heavy quarks in ultraperipheral heavy ion collisions. The integrated cross section and the rapidity distribution are computed employing sound high energy QCD formalisms as the collinear and semihard approaches as well as the saturation model. In particular, the color glass condensate (CGC) formalism is also considered using a simple phenomenological parameterization for the color field correlator in the medium, which allow us to obtain more reliable estimates for charm and bottom production at LHC energies.

The contribution of the QCD Pomeron to the process AA → AA J/Ψ J/Ψ is discussed. We focus on the photon-photon collision, with the quasi-real photon coming from the Weizsäcker -Williams spectrum of the nuclei. We calculate the cross section for this process considering the solution of the LLA BFKL equation at zero momentum transfer using a small t approximation for the differential cross section of the subprocess. Furthermore, the impact of non-leading corrections to the BFKL equation is also analyzed. In both cases the cross section is found to increase with the energy, predicting considerable values for the LHC energies. Moreover, we compare our results with the Born two-gluon approximation, which is energy independent at the photon level. Our results indicate that the experimental analyzes of this process can be useful to discriminate the QCD dynamics at high energies. 25.75.Dw, 13.60.Le

One of the frontiers of QCD which are intensely investigated in high energy experiments is the high energy (small x) regime, where we expect to observe the non-linear behavior of the theory. In this regime, the growth of the parton distribution should saturate, forming a Color Glass Condensate (CGC). In fact, signals of parton saturation have already been observed both in ep deep inelastic scattering at HERA and in deuteron-gold collisions at RHIC. Currently, a global description of the existing experimental data is possible considering different phenomenological saturation models for the two processes within the CGC formalism. In this letter we analyze the universality of these dipole cross section parameterizations and verify that they are not able to describe the HERA and RHIC data simultaneously. We analyze possible improvements in the parameterizations and propose a new parametrization for the forward dipole amplitude which allows us to describe quite well the small-x ep HERA data on F 2 structure function as well as the dAu RHIC data on charged hadron spectra. It is an important signature of the universality of the saturation physics.

The photoproduction of quarkonium in coherent hadron-hadron (pp/pA/AA) interactions for LHC energies is an important tool to investigate the QCD dynamics at high energies. In this paper we estimate the integrated cross section and rapidity distribution for J/Ψ and Υ production using the Color Glass Condensate (CGC) formalism. We predict large rates, implying that the experimental identification could be feasible at the LHC.

We show that the cross section for inclusive charm production exhibits geometric scaling in a large range of photon virtualities. In the HERA kinematic domain the saturation momentum Q 2 sat (x) stays below the hard scale µ 2 c = 4m 2 c , implying charm production probing mostly the color transparency regime and unitarization effects being almost negligible. We derive our results considering two saturation models which are able to describe the DESY ep collider HERA data for the proton structure function at small values of the Bjorken variable x. A striking feature is the scaling on τ ≡ Q 2 /Q 2 sat (x) above saturation limit, corroborating recent theoretical studies.PACS numbers: 12.38.Bx; 13.60.HbIntroduction. The behavior of ep/pp scattering in the limit of high center-of-mass energy √ s and fixed momentum transfer is one of the outstanding open questions in the theory of the strong interactions. Over the past few years much theoretical effort has been devoted towards the understanding of the growth of the total scattering cross sections with energy. These studies are mainly motivated by the violation of the unitarity (or Froissart) bound by the solutions of the linear perturbative DGLAP [1] and BFKL [2] evolution equations. Since these evolution equations predict that the cross section rises obeying a power law of the energy, violating the Froissart bound [3], new dynamical effects associated with the unitarity corrections are expected to stop its further growth [4,5]. This expectation can be easily understood: while for large momentum transfer k ⊥ , the BFKL equation predicts that the mechanism g → gg populates the transverse space with a large number of small size gluons per unit of rapidity (the transverse size of a gluon with momentum k ⊥ is proportional to 1/k ⊥ ), for small k ⊥ the produced gluons overlap and fusion processes, gg → g, are equally important. Considering the latter process, the rise of the gluon distribution below a typical scale is reduced, restoring the unitarity. That typical scale is energy dependent and is called saturation scale Q sat . The saturation momentum sets the critical transverse size for the unitarization of the cross sections. In other words, unitarity is restored by including non-linear corrections in the evolution equations [4,5,6,7,8,9,10,11,12,13,14,15,16,17]. Such effects are small for k 2 ⊥ > Q 2 sat and very strong for k 2 ⊥ < Q 2 sat , leading to the saturation of the scattering amplitude. The successful description of all inclusive and diffractive deep inelastic data at the collider HERA by saturation models [18,19,20] suggests that these effects might become important in the energy regime probed by