A fixed-target programme at the LHC: Physics case and projected performances for heavy-ion, hadron, spin and astroparticle studies

Hadjidakis, C.; Kikoła, D. P.; Lansberg, J. P.; Massacrier, L.; Echevarría, Miguel G.; Kusina, A.; Schienbein, I.; Seixas, J.; Shao, Hua-Sheng; Signori, Andrea; Trzeciak, B. A.; Brodsky, Stanley J.; Cavoto, G.; Silva, C. Da; Donato, Fiorenza; Ferreiro, E. G.; Hřivnáčová, I.; Klein, A.; Kurepin, A.; Lorcé, Cedric; Lyonnet, F.; Makdisi, Y. I.; Houssais, S. Porteboeuf; Quintans, C.; Rakotozafindrabe, A.; Robbe, P.; Scandale, W.; Topilskaya, N.; Uras, A.; Wagner, J.; Yamanaka, Nodoka; Yang, Z.; Zelenski, A.

doi:10.1016/j.physrep.2021.01.002

“…The IC mechanisms shall have a significant impact on the hard processes with moderate factorization scales at those colliders with a relatively lower center-of-mass energy. Therefore, colliders with high luminosity at lower center-of-mass energy, such as the fixed-target experiment (like After@LHC [354][355][356][357][358] operating at a center-of-mass energy √ s = 115 GeV) and future electron-ion colliders (e.g., EIC US [30] and EicC, etc. ), would be ideally suited to discover or constrain the intrinsic content in nucleon.…”

Section: Intrinsic Charmmentioning

confidence: 99%

Electron-ion collider in China

Anderle

¹

,

Bertone

²

,

Cao

³

et al. 2021

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Lepton scattering is an established ideal tool for studying inner structure of small particles such as nucleons as well as nuclei. As a future high energy nuclear physics project, an Electron-ion collider in China (EicC) has been proposed. It will be constructed based on an upgraded heavy-ion accelerator, High Intensity heavy-ion Accelerator Facility (HIAF) which is currently under construction, together with a new electron ring. The proposed collider will provide highly polarized electrons (with a polarization of ∼80%) and protons (with a polarization of ∼70%) with variable center of mass energies from 15 to 20 GeV and the luminosity of (2–3) × 1033 cm−2 · s−1. Polarized deuterons and Helium-3, as well as unpolarized ion beams from Carbon to Uranium, will be also available at the EicC.The main foci of the EicC will be precision measurements of the structure of the nucleon in the sea quark region, including 3D tomography of nucleon; the partonic structure of nuclei and the parton interaction with the nuclear environment; the exotic states, especially those with heavy flavor quark contents. In addition, issues fundamental to understanding the origin of mass could be addressed by measurements of heavy quarkonia near-threshold production at the EicC. In order to achieve the above-mentioned physics goals, a hermetical detector system will be constructed with cutting-edge technologies.This document is the result of collective contributions and valuable inputs from experts across the globe. The EicC physics program complements the ongoing scientific programs at the Jefferson Laboratory and the future EIC project in the United States. The success of this project will also advance both nuclear and particle physics as well as accelerator and detector technology in China.

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“…As what regards the experimental setups where η b hadroproduction cross sections could be measured in pp collisions, let us cite the LHC in the collider and fixed-target modes, in particular with the LHCb detector. The latter mode has been studied in details in [96][97][98][99] as what regards quarkonium production. Its nominal √ s for 7 TeV proton beams reaches 114.6 GeV.…”

Section: A Digression On the η B Detectabilitymentioning

confidence: 99%

Curing the unphysical behaviour of NLO quarkonium production at the LHC and its relevance to constrain the gluon PDF at low scales

Lansberg

¹

,

Ozcelik

²

2021

Self Cite

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We address the unphysical energy dependence of quarkonium-hadroproduction cross sections at Next-to-Leading Order (NLO) in $$\alpha _s$$ α s which we attribute to an over-subtraction in the factorisation of the collinear singularities inside the PDFs in the $$\overline{\text {MS}}$$ MS ¯ scheme. Such over- or under-subtractions have a limited phenomenological relevance in most of the scattering processes in particle physics. On the contrary, it is particularly harmful for $$P_T$$ P T -integrated charmonium hadroproduction which renders a wide class of NLO results essentially unusable. Indeed, in such processes, $$\alpha _s$$ α s is not so small, the PDFs are not evolved much and can be rather flat for the corresponding momentum fractions and, finally, some process-dependent NLO pieces are either too small or too large. We propose a scale-fixing criterion which avoids such an over-subtraction. We demonstrate its efficiency for $$\eta _{c,b}$$ η c , b but also for a fictitious light elementary scalar boson. Having provided stable NLO predictions for $$\eta _{c,b}$$ η c , b $$P_T$$ P T -integrated cross sections, $$\sigma ^{\mathrm{NLO}}_{\eta _Q}$$ σ η Q NLO , and discussed the options to study $$\eta _{b}$$ η b hadroproduction, we argue that their measurement at the LHC can help better determine the gluon PDF at low scales and tell whether the local minimum in conventional NLO gluon PDFs around $$x=0.001$$ x = 0.001 at scales below 2 GeV is physical or not.

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“…During the last decade, a large amount of data have been collected by the LHC considering pp, p Pb and PbPb collisions in the collider mode for different center-of-mass energies [15][16][17][18][19][20][21][22][23]. In recent years, the possibility of study a complementary kinematical range in fixed-target collisions at the LHC was proposed [59,60] and the analysis of these collisions became a reality by the injection of noble gases (He, N e, Ar ) in the LHC beam pipe by the LHCb Collaboration [79] using the System for Measuring Overlap with Gas (SMOG) device [80]. For the typical fixed-target p A and Pb A configurations, the center-of-mass energies reached were √ s N N ≈ 110 GeV and √ s N N ≈ 69 GeV, respectively, with the associated data having been used to improve our understanding of the nuclear effects present in p A collisions [81,82] and, in the particular case of pHe collisions, to shed light on the antiproton production (see e.g.…”

Section: Resultsmentioning

confidence: 99%

“…It is important to emphasize that although a Pb target is not possible with the SMOG system, we decided to present the associated predictions since it can envisioned with a solid target and a bent crystal, as discussed in Refs. [59,60]. One has that in the J/ case, the Regge model provides the upper bound.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Near threshold heavy vector meson photoproduction at LHC and EicC

Xie

¹

,

Gonçalves

²

2021

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The exclusive $$J/\Psi $$ J / Ψ and $$\Upsilon $$ Υ photoproduction in fixed - target collisions at the LHC and ep(A) collisions at the Electron ion collider in China (EicC) is investigated considering different models for the treatment of the vector meson production at low energies, close to the threshold. Results for the total cross sections and associated distributions are presented. We predict a large number of $$J/\Psi $$ J / Ψ events at the LHC in the rapidity range covered by the LHCb detector. For the EicC, our predictions point out that a detailed analysis of the near threshold $$J/\Psi $$ J / Ψ and $$\Upsilon $$ Υ photoproduction is feasible. Moreover, our results indicate that the modeling of the near threshold vector meson production can be constrained by future experimental analyzes at the LHC and EicC.

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A fixed-target programme at the LHC: Physics case and projected performances for heavy-ion, hadron, spin and astroparticle studies

Cited by 48 publications

References 437 publications

Electron-ion collider in China

Electron-ion collider in China

Curing the unphysical behaviour of NLO quarkonium production at the LHC and its relevance to constrain the gluon PDF at low scales

Near threshold heavy vector meson photoproduction at LHC and EicC

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