Momentum In Collisions Research Articles

Investigation of early magnetic field and angular momentum in ultrarelativistic heavy-ion collisions via D*+ spin alignment with ALICE

Heavy quarks, i.e. charm and beauty, are produced at the initial stages of heavy-ion collisions, on a time scale shorter than the medium formation time, and are sensitive to the initial angular momentum of the system and the magnetic field produced perpendicular to the reaction plane (defined by the impact parameter direction and beam direction) in non-central heavy-ion collisions. In the presence of a large angular momentum and initial magnetic field, the charm quark can be polarized. Experimentally, the heavy-flavor polarization can be probed by measuring the spin density matrix element (ρ00) of spin-1 mesons such as D*+ mesons. Any deviation of the parameter from 1/3 can be attributed to the spin alignment of the D∗+ meson. In these proceedings, we present the first measurement of the ρ00 parameter of prompt D*+ mesons in Pb–Pb collisions at √sNN = 5.02 TeV, exploiting the data sample collected by the ALICE Collaboration during LHC Run 2. A comparison with the J/ψ polarization measurement is also reported to investigate the effect of the magnetic field. Moreover, the ρ00 parameter of D*+ mesons measured in pp collisions is also presented.

Cross-code comparison of the edge codes SOLPS-ITER, SOLEDGE2D and UEDGE in modelling a high-power neon-seeded scenario in the DTT

Abstract In this work, we cross-compare the state-of-the-art edge plasma codes SOLPS-ITER, SOLEDGE2D, and UEDGE in a reactor-relevant neon-seeded Divertor Tokamak Test (DTT) scenario at nominal power, extending the simplified test-bed of Moscheni et al. (2022). Converged solutions targeting the same separatrix density and radiated power are obtained by adjusting the pumping albedo and the neon puffing rate. This higher-power scenario is generally characterised by substantial disagreement between the three codes, up to 78-178% in peak heat fluxes. Discrepancies found in Moscheni et al. (2022) are indeed exacerbated, and new ones arise. Underlying causes include the over-penetration of neutrals implied by the unified ion-neutral temperature of UEDGE (observed in Moscheni et al. (2022)), here resulting in a 38-114% over-estimation of core plasma densities. The particular set of EIRENE atomic-molecular reactions adopted is found to stiffly restrict the achievable code solutions, which results in the predicted effective charge Z eff changing from ∽5 to ∽8 at the outer mid-plane separatrix. The strong link between Z eff, main ion density and unified ion temperature emphasises the need of proper assessments of impurity cross-field transport, with its implications on core contamination and wall erosion. The advantages of extended plasma meshes are found to come with associated modelling intricacies, yet to be fully characterised but seemingly impacting on the activity around the secondary X-point of single-null magnetic topologies. An appreciable impurity particle imbalance, generated by the neon ion density floor, is noted—speculatively contributing to SOLEDGE2D's different radiation emission distribution, and expected to be even more deleterious for high-Z impurities in all the codes. Potential drivers of further discrepancies are the different Braginskii formulations of collision times and momentum sources in presence of impurities, and the SOLPS-ITER extra terms gaining importance around the detachment front. Outstanding questions unanswered in this work prompt further investigations.

Search for heavy resonances in final states with four leptons and missing transverse momentum or jets in pp collisions at s = 13 TeV with the ATLAS detector

A search for a new heavy boson produced via gluon-fusion in the four-lepton channel with missing transverse momentum or jets is performed. The search uses proton-proton collision data equivalent to an integrated luminosity of 139 fb−1 at a centre-of-mass energy of 13 TeV collected by the ATLAS detector between 2015 and 2018 at the Large Hadron Collider. This study explores the decays of heavy bosons: R → SH and A → ZH, where R is a CP-even boson, A is a CP-odd boson, H is a CP-even boson, and S is considered to decay into invisible particles that are candidates for dark matter. In these processes, S → invisible and H → ZZ. The Z boson associated with the heavy scalar boson H decays into all decay channels of the Z boson. The mass range under consideration is 390–1300 (320–1300) GeV for the R (A) boson and 220–1000 GeV for the H boson. No significant deviation from the Standard Model backgrounds is observed. The results are interpreted as upper limits at a 95% confidence level on the cross-section times the branching ratio of the heavy resonances.

[formula omitted] and [formula omitted] two-particle femtoscopic correlations in PbPb collisions at [formula omitted]

Two-particle correlations are presented for KS0, ▪, and ▪ strange hadrons as a function of relative momentum in lead-lead collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV. The dataset corresponds to an integrated luminosity of 0.607nb−1 and was collected using the CMS detector at the CERN LHC. These correlations are sensitive to quantum statistics and to final-state interactions between the particles. The source size extracted from the KS0KS0 correlations is found to decrease from 4.6 to 1.6fm in going from central to peripheral collisions. Strong interaction scattering parameters (i.e., scattering length and effective range) are determined from the ▪ and ▪ (including their charge conjugates) correlations using the Lednický–Lyuboshitz model and are compared to theoretical and other experimental results.

Search for direct production of electroweakinos in final states with one lepton, jets and missing transverse momentum in pp collisions at [formula omitted] TeV with the ATLAS detector

Search for direct production of electroweakinos in final states with one lepton, jets and missing transverse momentum in pp collisions at [formula omitted] TeV with the ATLAS detector

Probing collectivity in heavy-ion collisions with fluctuations of the pT spectrum

Event-by-event fluctuations in the initial stages of ultrarelativistic nucleus-nucleus collisions depend little on rapidity. The hydrodynamic expansion which occurs in later stages then gives rise to correlations among outgoing particles which depend weakly on their relative rapidity. Azimuthal correlations, through which anisotropic flow (vn(pT)) is defined, have been the most studied. Here we study a new observable introduced in 2020 by Schenke, Shen and Teaney and dubbed v0(pT), which quantifies the relative change in the pT spectrum induced by a fluctuation. We describe how it can be measured. Using hydrodynamic simulations, we make quantitative predictions for v0(pT) of charged and identified hadrons. We then discuss how v0(pT) relates to two phenomena which have been measured: The increase of the mean transverse momentum in ultracentral collisions, and the event-by-event fluctuations of the transverse momentum per particle [pT]. We show that v0(pT) determines the dependence of these quantities on the pT cuts implemented in the analysis. We quantitatively explain the rise of σpT observed by ATLAS as the upper pT-cut is increased from 2 to 5 GeV/c.

Rheological sand bed generates non‐rebounding particles

ABSTRACTWind‐blown sand movements induce desertification and cause various environmental problems. This study investigates the rebound probability of sand particles during sand transport. The widely used rebound probability models are essentially empirical and the mechanism that generates non‐rebounding particles remains unclear. By tracking the grain–bed collision process of impact particles in steady‐state sand flows, it was observed that non‐rebounding particles undergo repetitive collisional momentum losses within the rheological layer of the sand bed. Therefore, rebound probability models based on the incident velocity and angle cannot realistically describe rebound probability. Furthermore, the rheological sand bed produces numerous rebound particles with a coefficient of restitution above 1.0, converting the normal distribution of the coefficient of restitution into a lognormal distribution pattern with considerably larger variances. The new insights into aeolian rebounds gained through this study are expected to reduce the uncertainties in sand flux predictions.

Momentum-dependent measures of correlations between mean transverse momentum and harmonic flow in heavy-ion collisions

Momentum-dependent measures of correlations between mean transverse momentum and harmonic flow in heavy-ion collisions

Search for new particles in final states with a boosted top quark and missing transverse momentum in proton-proton collisions at s\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\sqrt{s} $$\\end{document} = 13 TeV with the ATLAS detector

A search for events with one top quark and missing transverse momentum in the final state is presented. The fully hadronic decay of the top quark is explored by selecting events with a reconstructed boosted top-quark topology produced in association with large missing transverse momentum. The analysis uses 139 fb−1 of proton-proton collision data at a centre-of-mass energy of s\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\sqrt{s} $$\\end{document} = 13 TeV recorded during 2015-2018 by the ATLAS detector at the Large Hadron Collider. The results are interpreted in the context of simplified models for Dark Matter particle production and the single production of a vector-like T quark. Without significant excess relative to the Standard Model expectations, 95% confidence-level upper limits on the corresponding cross-sections are obtained. The production of Dark Matter particles in association with a single top quark is excluded for masses of a scalar (vector) mediator up to 4.3 (2.3) TeV, assuming mχ = 1 GeV and the model couplings λq = 0.6 and λχ = 0.4 (a = 0.5 and gχ = 1). The production of a single vector-like T quark is excluded for masses below 1.8 TeV assuming a coupling to the top quark κT = 0.5 and a branching ratio for T → Zt of 25%.

Search for direct production of electroweakinos in final states with one lepton, jets and missing transverse momentum in pp collisions at s\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\sqrt{s} $$\\end{document} = 13 TeV with the ATLAS detector

Searches for electroweak production of wino-like chargino pairs, χ~1+χ~1−\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {\\overset{\\sim }{\\chi}}_1^{+}{\\overset{\\sim }{\\chi}}_1^{-} $$\\end{document}, and of wino-like chargino and next-to-lightest neutralino, χ~1±χ~20\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {\\overset{\\sim }{\\chi}}_1^{\\pm }{\\overset{\\sim }{\\chi}}_2^0 $$\\end{document}, are presented. The models explored assume that the charginos decay into a W boson and the lightest neutralino, χ~1±→W±χ~10\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {\\overset{\\sim }{\\chi}}_1^{\\pm}\ o {W}^{\\pm }{\\overset{\\sim }{\\chi}}_1^0 $$\\end{document}. The next-to-lightest neutralinos are degenerate in mass with the chargino and decay to χ~10\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {\\overset{\\sim }{\\chi}}_1^0 $$\\end{document} and either a Z or a Higgs boson, χ~20→Zχ~10\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {\\overset{\\sim }{\\chi}}_2^0\ o Z{\\overset{\\sim }{\\chi}}_1^0 $$\\end{document} or hχ~10\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ h{\\overset{\\sim }{\\chi}}_1^0 $$\\end{document}. The searches exploit the presence of a single isolated lepton and missing transverse momentum from the W boson decay products and the lightest neutralinos, and the presence of jets from hadronically decaying Z or W bosons or from the Higgs boson decaying into a pair of b-quarks. The searches use 139 fb−1 of s\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\sqrt{s} $$\\end{document} = 13 TeV proton-proton collisions data collected by the ATLAS detector at the Large Hadron Collider between 2015 and 2018. No deviations from the Standard Model expectations are found, and 95% confidence level exclusion limits are set. Chargino masses ranging from 260 to 520 GeV are excluded for a massless χ~10\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {\\overset{\\sim }{\\chi}}_1^0 $$\\end{document} in chargino pair production models. Degenerate chargino and next-to-lightest neutralino masses ranging from 260 to 420 GeV are excluded for a massless χ~10\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {\\overset{\\sim }{\\chi}}_1^0 $$\\end{document} for χ~20→Zχ~10\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {\\overset{\\sim }{\\chi}}_2^0\ o Z{\\overset{\\sim }{\\chi}}_1^0 $$\\end{document}. For decays through an on-shell Higgs boson and for mass-splitting between χ~1±/χ~20\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {\\overset{\\sim }{\\chi}}_1^{\\pm }/{\\overset{\\sim }{\\chi}}_2^0 $$\\end{document} and χ~10\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {\\overset{\\sim }{\\chi}}_1^0 $$\\end{document} as small as the Higgs boson mass, mass limits are improved by up to 40 GeV in the range of 200–260 GeV and 280–470 GeV compared to previous ATLAS constraints.

Development of a Practical Tool for Linear Momentum Collisions Using a Microcontroller

Purpose of the study: This research aims to develop a linear momentum collision practical tool with a microcontroller so that the results obtained are more accurate, the time used is more efficient and the experiments carried out are more varied.
 Methodology:This research is R & D research with development procedures, namely the potential and problem stages, data collection, product design, design validation, product design revision, product testing, final product. The subjects in this research were 2 media expert lecturers, 2 material expert lecturers, 20 pre-research students, 4 limited test students and 38 broad test students. Data collection techniques use observation, documentation and questionnaire techniques. The data analysis technique used is descriptive qualitative and quantitative .
 Main Findings: The results of research on the development of linear momentum collision practical equipment with a microcontroller obtained a value from material expert tests of 3.8 with an ideal percentage of 94%, from media expert tests of 3.91 with an ideal percentage of 97.5%, from limited field tests of 3.93 with an ideal percentage of 78.75% and from tests The wide field is 3.85 with an ideal percentage of 77%.
 Novelty/Originality of this study: The novelty of this research is the development of a linear momentum collision practical tool whose instrument part is for measuring the speed of objects determined using an ATmega 16 microcontroller and an ultrasonic sensor as a distance sensor. This learning media can be useful in improving the physics learning process to be more meaningful

Search for new physics in multijet events with at least one photon and large missing transverse momentum in proton-proton collisions at 13 TeV

A search for new physics in final states consisting of at least one photon, multiple jets, and large missing transverse momentum is presented, using proton-proton collision events at a center-of-mass energy of 13 TeV. The data correspond to an integrated luminosity of 137 fb−1, recorded by the CMS experiment at the CERN LHC from 2016 to 2018. The events are divided into mutually exclusive bins characterized by the missing transverse momentum, the number of jets, the number of b-tagged jets, and jets consistent with the presence of hadronically decaying W, Z, or Higgs bosons. The observed data are found to be consistent with the prediction from standard model processes. The results are interpreted in the context of simplified models of pair production of supersymmetric particles via strong and electroweak interactions. Depending on the details of the signal models, gluinos and squarks of masses up to 2.35 and 1.43 TeV, respectively, and electroweakinos of masses up to 1.23 TeV are excluded at 95% confidence level.

Relative attitude stability analysis of double satellite formation for gravity field exploration in space debris environment

Spacecraft operating in low orbit are at risk of being hit by space debris. In the debris environment, the impact of debris is likely to cause the double satellite formation to exit science mode or even lead to the divergence of the control system, thus affecting the scientific exploration mission. In this paper, the attitude stability of the double satellite formation for gravity field in the near circular and polar orbit in the space debris environment is studied. Firstly, based on Lyapunov control and LQR, two sets of control models of stochastic collision for two satellites aligned with each other were proposed, and the actuators were modelled and assigned. Secondly, models of collision probability and momentum are developed. The distribution law of space debris is obtained according to the international common debris software. Meanwhile, probability density function of two independent collisions is gained. Finally, through Monte Carlo simulation and statistics, the changes of relative attitude and thrust torque are simulated when the satellite obtains the angular momentum for a short period of time due to being impacted by space debris. During the 10-year mission period, the number of times that the space debris impact makes the satellite attitude out of the science mode and the number of times that the control system diverges are obtained, which provides a reference for the normal manner of the double satellite formation for gravity field exploration.

Anisotropic flow and the valence quark skeleton of hadrons

We study transverse momentum anisotropies, in particular, the elliptic flow v2 due to the interference effect sourced by valence quarks in high-energy hadron-hadron collisions. Our main formula is derived as the high-energy (eikonal) limit of the impact-parameter dependent cross section in quantum field theory, which agrees with that in terms of the impact parameter in the classical picture. As a quantitative assessment of the interference effect, we calculate v2 in the azimuthal distribution of gluons at a comprehensive coverage of the impact parameter and the transverse momentum in high-energy pion-pion collisions. In a broad range of the impact parameter, a sizable amount of v2, comparable with that produced due to saturated dense gluons or final-state interactions, is found to develop. This is in contrast with similar studies in heavy-ion collisions using classical color charge distributions in which such a contribution from geometric correlations was found to be small and has, hence, been ignored in recent studies. In our calculations, the valence sector of the pion wave function is obtained numerically from the Basis Light-Front Quantization, a non-perturbative light-front Hamiltonian approach. And our formalism is generic and can be applied to other small collision systems like proton-proton collisions.

Search for pair-produced vector-like top and bottom partners in events with large missing transverse momentum in pp collisions with the ATLAS detector

A search for pair-produced vector-like quarks using events with exactly one lepton (e or mu ), at least four jets including at least one b-tagged jet, and large missing transverse momentum is presented. Data from proton–proton collisions at a centre-of-mass energy of sqrt{s}=13 text {TeV}, recorded by the ATLAS detector at the LHC from 2015 to 2018 and corresponding to an integrated luminosity of 139 fb^{-1}, are analysed. Vector-like partners T and B of the top and bottom quarks are considered, as is a vector-like X with charge +5/3, assuming their decay into a W, Z, or Higgs boson and a third-generation quark. No significant deviations from the Standard Model expectation are observed. Upper limits on the production cross-section of T and B quark pairs as a function of their mass are derived for various decay branching ratio scenarios. The strongest lower limits on the masses are 1.59 text {TeV} assuming mass-degenerate vector-like quarks and branching ratios corresponding to the weak-isospin doublet model, and 1.47 text {TeV} (1.46 text {TeV}) for exclusive T rightarrow Zt (B/X rightarrow Wt) decays. In addition, lower limits on the T and B quark masses are derived for all possible branching ratios.

Probing nuclear structure with mean transverse momentum in relativistic isobar collisions

Probing nuclear structure with mean transverse momentum in relativistic isobar collisions

Angular Momentum Loss due to Tidal Effects in the Post-Minkowskian Expansion.

We calculate the tidal corrections to the loss of angular momentum in a two-body collision at leading post-Minkowskian order from an amplitude-based approach. The eikonal operator allows us to efficiently combine elastic and inelastic amplitudes, and captures both the contributions due to genuine gravitational-wave emissions and those due to the static gravitational field. We calculate the former by harnessing powerful collider-physics techniques such as reverse unitarity, thereby reducing them to cut two-loop integrals, and cross check the result by performing an independent calculation in the post-Newtonian limit. For the latter, we can employ the results of P. Di Vecchia et al. [Angular momentum of zero-frequency gravitons, J. High Energy Phys. 08 (2022) 172.JHEPFG1029-847910.1007/JHEP08(2022)172], where static-field effects were calculated for generic gravitational scattering events using the leading soft graviton theorem.

Search for new phenomena in final states with photons, jets and missing transverse momentum in pp collisions at sqrt{s} = 13 TeV with the ATLAS detector

A search for new phenomena has been performed in final states with at least one isolated high-momentum photon, jets and missing transverse momentum in proton–proton collisions at a centre-of-mass energy of sqrt{s} = 13 TeV. The data, collected by the ATLAS experiment at the CERN LHC, correspond to an integrated luminosity of 139 fb−1. The experimental results are interpreted in a supersymmetric model in which pair-produced gluinos decay into neutralinos, which in turn decay into a gravitino, at least one photon, and jets. No significant deviations from the predictions of the Standard Model are observed. Upper limits are set on the visible cross section due to physics beyond the Standard Model, and lower limits are set on the masses of the gluinos and neutralinos, all at 95% confidence level. Visible cross sections greater than 0.022 fb are excluded and pair-produced gluinos with masses up to 2200 GeV are excluded for most of the NLSP masses investigated.

Nonlinear ion-stopping calculations for a classical free-electron gas at high projectile energies

In this work, we solved the classical equations of motion and Poisson equation self-consistently, equivalent to the nonlinear Vlasov-Poisson equation, for a projectile moving in a static free-electron gas to calculate the full noncentral self-consistent electron-ion potential, and thus the ion stopping power. We investigated the origin of the Barkas effect, namely, the first nonlinear effect for projectiles at high velocities responsible for the difference between the energy-loss results for positively and negatively charged ions traversing the same target. This effect is strongly enhanced by the multipolar part of the electron-ion potential as first suggested by Lindhard [J. Lindhard, Nucl. Instr. and Meth. 132, 1438 (1976)]. Moreover, this effect is partially related to the nonconservation of the angular momentum in electron-ion collisions. These nonlinear calculations are applied to understanding the stopping of protons and antiprotons in Al at high projectile energies.

Rapidity-only TMD factorization at one loop

Typically, a production of a particle with a small transverse momentum in hadron-hadron collisions is described by CSS-based TMD factorization at moderate Bjorken xB ~ 1 and by kT-factorization at small xB. A uniform description valid for all xB is provided by rapidity-only TMD factorization developed in a series of recent papers at the tree level. In this paper the rapidity-only TMD factorization for particle production by gluon fusion is extended to the one-loop level.