Quarkonium Production at Collider Energies in Small-x Formalism

Watanabe, K.

doi:10.1007/s00601-017-1297-z

Cited by 7 publications

(8 citation statements)

References 101 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[59] it is shown that c ≈ 0.25−0.5 yields a reasonable fit to the nuclear structure function F 2,A (x, Q 2 ) at x = 0.0125 measured by New Muon Collaboration. Indeed, the CGC model calculation with a smaller value ofĉ ∼ 3 (c ∼ 0.5) has resulted in more reasonable description of forward heavy-flavor production as well as quarkonium production in p + A collisions [52,[60][61][62][63] compared to the early predictions withĉ = 4-6 [51,64]. In this paper, we chooseĉ in the range of 2 ≤ĉ ≤ 3 for the initial saturation scale in heavy nuclei, Pb (A = 208) and Au (A = 197).…”

Section: Jhep12(2020)181mentioning

confidence: 99%

Comparison of improved TMD and CGC frameworks in forward quark dijet production

Fujii¹,

Marquet²,

Watanabe³

2020

J. High Energ. Phys.

Self Cite

View full text Add to dashboard Cite

For studying small-x gluon saturation in forward dijet production in high-energy dilute-dense collisions, the improved TMD (ITMD) factorization formula was recently proposed. In the Color Glass Condensate (CGC) framework, it represents the leading term of an expansion in inverse powers of the hard scale. It contains the leading-twist TMD factorization formula relevant for small gluon’s transverse momentum kt, but also incorporates an all-order resummation of kinematical twists, resulting in a proper matching to high-energy factorization at large kt. In this paper, we evaluate the accuracy of the ITMD formula quantitatively, for the case of quark dijet production in high-energy proton-proton(p+p) and proton-nucleus (p+A) collisions at LHC energies. We do so by comparing the quark-antiquark azimuthal angle ∆ϕ distribution to that obtained with the CGC formula. For a dijet with each quark momentum pt much larger than the target saturation scale, Qs, the ITMD formula is a good approximation to the CGC formula in a wide range of azimuthal angle. It becomes less accurate as the jet pt’s are lowered, as expected, due to the presence of genuine higher-twists contributions in the CGC framework, which represent multi-body scattering effects absent in the ITMD formula. We find that, as the hard jet momenta are lowered, the accuracy of ITMD start by deteriorating at small angles, in the high-energy-factorization regime, while in the TMD regime near ∆ϕ = π, very low values of pt are needed to see differences between the CGC and the ITMD formula. In addition, the genuine twists corrections to ITMD become visible for higher values of pt in p + A collisions, compared to p+p collisions, signaling that they are enhanced by the target saturation scale.

show abstract

Section: Jhep12(2020)181mentioning

confidence: 99%

Comparison of improved TMD and CGC frameworks in forward quark dijet production

Fujii¹,

Marquet²,

Watanabe³

2020

J. High Energ. Phys.

Self Cite

View full text Add to dashboard Cite

show abstract

“…A key consequence of the saturation scale defined as: Q 2 sat ∼ A 1/3 x −0.3 with A the mass number, is that the same scale for heavy nuclei in heavy ion colliders is comparable with heavy quark mass. We borrow from a relevant formalism for quarkonia given in [132,133] for the arguments hereafter. In the case of pA collisions and in the nucleus (A) rest frame, the interaction time when proton scatters off the nucleus is characterized τ int ∼ R A .…”

Section: Single Inclusive Productionmentioning

confidence: 99%

Mining for Gluon Saturation at Colliders

Morreale

Salazar

2021

Universe

View full text Add to dashboard Cite

Quantum chromodynamics (QCD) is the theory of strong interactions of quarks and gluons collectively called partons, the basic constituents of all nuclear matter. Its non-abelian character manifests in nature in the form of two remarkable properties: color confinement and asymptotic freedom. At high energies, perturbation theory can result in the growth and dominance of very gluon densities at small-x. If left uncontrolled, this growth can result in gluons eternally growing violating a number of mathematical bounds. The resolution to this problem lies by balancing gluon emissions by recombinating gluons at high energies: phenomena of gluon saturation. High energy nuclear and particle physics experiments have spent the past decades quantifying the structure of protons and nuclei in terms of their fundamental constituents confirming predicted extraordinary behavior of matter at extreme density and pressure conditions. In the process they have also measured seemingly unexpected phenomena. We will give a state of the art review of the underlying theoretical and experimental tools and measurements pertinent to gluon saturation physics. We will argue for the need of high energy electron-proton/ion colliders such as the proposed EIC (USA) and LHeC (Europe) to consolidate our knowledge of QCD knowledge in the small x kinematic domains.

show abstract

“…( 14). 7 A systematic study of the range of validity of that approximation will be assessed in a separate publication. Third, while the color singlet is suppressed relative to the color octet, in NRQCD all states are weighted with different LDMEs; hence, both color states have to be kept.…”

Section: Vector Meson Productionmentioning

confidence: 99%

“…where S ⊥ represents the transverse area of the proton in the R ⊥ -independent case [48]. 9 This procedure yields the Fourier transform of the two-point correlator in the 7 This approximation also modifies the hard factor…”

Section: Two-point Correlatormentioning

confidence: 99%

“…The study of rapidity dependent vector meson production in hadronic collisions, in combination with charged hadron production, is well suited to test saturation effects at a semi-hard scale of a few GeV [7]. In a nutshell, heavy vector mesons, whose mass is of the order of magnitude of the saturation scale, will be less sensitive to saturation effects than lighter charged hadrons at similar transverse momenta and rapidities.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Accessing subnuclear fluctuations and saturation with multiplicity dependent $J/ψ$ production in p+p and p+Pb collisions

Salazar,

Schenke,

Soto-Ontoso

2021

Preprint

View full text Add to dashboard Cite

We study the production of J/ψ vector mesons as a function of charged hadron multiplicity in p + p and p + P b collisions at LHC energies. We employ the color glass condensate framework, using running coupling Balitsky-Kovchegov evolved dipole amplitudes, to compute gluon and cc-pair production. We use fragmentation functions to obtain charged hadrons, and explore two different hadronization schemes for the J/ψ: non-relativistic quantum chromodynamics and the improved color evaporation model. In our framework, event-by-event multiplicity fluctuations of both hadrons and J/ψ are driven by geometric and saturation scale normalization fluctuations. Studying the correlation between J/ψ and hadron multiplicity, we show that the characteristic difference between forward and backward rapidity in p + P b collisions is a result of different degrees of saturation probed at different rapidities. We demonstrate that experimental data on heavy-flavor production as a function of event activity provide stringent constraints on the fluctuating proton structure.

show abstract

Quarkonium Production at Collider Energies in Small-x Formalism

Abstract: I present a short review of recent studies of quarkonium production in proton-proton and protonnucleus collisions at collider energies in Small-x formalism.

Cited by 7 publications

References 101 publications

Comparison of improved TMD and CGC frameworks in forward quark dijet production

Comparison of improved TMD and CGC frameworks in forward quark dijet production

Mining for Gluon Saturation at Colliders

Accessing subnuclear fluctuations and saturation with multiplicity dependent $J/ψ$ production in p+p and p+Pb collisions

Contact Info

Product

Resources

About