| 41. |
- Acharya, S., et al.
(författare)
-
Forward rapidity J/ψ production as a function of charged-particle multiplicity in pp collisions at √s = 5.02 and 13 TeV
- 2022
-
Ingår i: Journal of High Energy Physics. - 1029-8479. ; 2022:6
-
Tidskriftsartikel (refereegranskat)abstract
- The production of J/ψ is measured as a function of charged-particle multiplicity at forward rapidity in proton-proton (pp) collisions at center-of-mass energies s = 5.02 and 13 TeV. The J/ψ mesons are reconstructed via their decay into dimuons in the rapidity interval (2.5 < y < 4.0), whereas the charged-particle multiplicity density (dNch/dη) is measured at midrapidity (|η| < 1). The production rate as a function of multiplicity is reported as the ratio of the yield in a given multiplicity interval to the multiplicity-integrated one. This observable shows a linear increase with charged-particle multiplicity normalized to the corresponding average value for inelastic events (dNch/dη/〈dNch/dη〉), at both the colliding energies. Measurements are compared with available ALICE results at midrapidity and theoretical model calculations. First measurement of the mean transverse momentum (〈pT〉) of J/ψ in pp collisions exhibits an increasing trend as a function of dNch/dη/〈dNch/dη〉 showing a saturation towards high charged-particle multiplicities. [Figure not available: see fulltext.] © 2022, The Author(s).
|
|
| 42. |
- Acharya, S., et al.
(författare)
-
General balance functions of identified charged hadron pairs of (π,K,p) in Pb–Pb collisions at sNN= 2.76 TeV
- 2022
-
Ingår i: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 833
-
Tidskriftsartikel (refereegranskat)abstract
- First measurements of balance functions (BFs) of all combinations of identified charged hadron (π,K,p) pairs in Pb–Pb collisions at sNN=2.76 TeV recorded by the ALICE detector are presented. The BF measurements are carried out as two-dimensional differential correlators versus the relative rapidity (Δy) and azimuthal angle (Δφ) of hadron pairs, and studied as a function of collision centrality. The Δφ dependence of BFs is expected to be sensitive to the light quark diffusivity in the quark–gluon plasma. While the BF azimuthal widths of all pairs substantially decrease from peripheral to central collisions, the longitudinal widths exhibit mixed behaviors: BFs of ππ and cross-species pairs narrow significantly in more central collisions, whereas those of KK and pp are found to be independent of collision centrality. This dichotomy is qualitatively consistent with the presence of strong radial flow effects and the existence of two stages of quark production in relativistic heavy-ion collisions. Finally, the first measurements of the collision centrality evolution of BF integrals are presented, with the observation that charge balancing fractions are nearly independent of collision centrality in Pb–Pb collisions. Overall, the results presented provide new and challenging constraints for theoretical models of hadron production and transport in relativistic heavy-ion collisions. © 2022 European Organization for Nuclear Research, ALICE
|
|
| 43. |
- Acharya, S., et al.
(författare)
-
Hypertriton Production in p -Pb Collisions at sNN =5.02 TeV
- 2022
-
Ingår i: Physical Review Letters. - 0031-9007. ; 128:25
-
Tidskriftsartikel (refereegranskat)abstract
- The study of nuclei and antinuclei production has proven to be a powerful tool to investigate the formation mechanism of loosely bound states in high-energy hadronic collisions. The first measurement of the production of HΛ3 in p-Pb collisions at sNN=5.02 TeV is presented in this Letter. Its production yield measured in the rapidity interval -1
|
|
| 44. |
- Acharya, S., et al.
(författare)
-
Inclusive and multiplicity dependent production of electrons from heavy-flavour hadron decays in pp and p-Pb collisions
- 2023
-
Ingår i: Journal of High Energy Physics. - 1029-8479. ; 2023:8
-
Tidskriftsartikel (refereegranskat)abstract
- Measurements of the production of electrons from heavy-flavour hadron decays in pp collisions at s = 13 TeV at midrapidity with the ALICE detector are presented down to a transverse momentum (p T) of 0.2 GeV/c and up to p T = 35 GeV/c, which is the largest momentum range probed for inclusive electron measurements in ALICE. In p-Pb collisions, the production cross section and the nuclear modification factor of electrons from heavy-flavour hadron decays are measured in the p T range 0.5 < p T < 26 GeV/c at sNN = 8.16 TeV. The nuclear modification factor is found to be consistent with unity within the statistical and systematic uncertainties. In both collision systems, first measurements of the yields of electrons from heavy-flavour hadron decays in different multiplicity intervals normalised to the multiplicity-integrated yield (self-normalised yield) at midrapidity are reported as a function of the self-normalised charged-particle multiplicity estimated at midrapidity. The self-normalised yields in pp and p-Pb collisions grow faster than linear with the self-normalised multiplicity. A strong p T dependence is observed in pp collisions, where the yield of high-p T electrons increases faster as a function of multiplicity than the one of low-p T electrons. The measurement in p-Pb collisions shows no p T dependence within uncertainties. The self-normalised yields in pp and p-Pb collisions are compared with measurements of other heavy-flavour, light-flavour, and strange particles, and with Monte Carlo simulations. [Figure not available: see fulltext.] © 2023, The Author(s).
|
|
| 45. |
|
|
| 46. |
- Acharya, S., et al.
(författare)
-
Inclusive, prompt and non-prompt J/ψ production at midrapidity in p-Pb collisions at √sNN = 5.02 TeV
- 2022
-
Ingår i: Journal of High Energy Physics. - 1029-8479. ; 2022:6
-
Tidskriftsartikel (refereegranskat)abstract
- A measurement of inclusive, prompt, and non-prompt J/ψ production in p-Pb collisions at a nucleon-nucleon centre-of-mass energy sNN = 5.02 TeV is presented. The inclusive J/ψ mesons are reconstructed in the dielectron decay channel at midrapidity down to a transverse momentum pT = 0. The inclusive J/ψ nuclear modification factor RpPb is calculated by comparing the new results in p-Pb collisions to a recently measured proton-proton reference at the same centre-of-mass energy. Non-prompt J/ψ mesons, which originate from the decay of beauty hadrons, are separated from promptly produced J/ψ on a statistical basis for pT larger than 1.0 GeV/c. These results are based on the data sample collected by the ALICE detector during the 2016 LHC p-Pb run, corresponding to an integrated luminosity Lint = 292 ± 11 μb−1, which is six times larger than the previous publications. The total uncertainty on the pT-integrated inclusive J/ψ and non-prompt J/ψ cross section are reduced by a factor 1.7 and 2.2, respectively. The measured cross sections and RpPb are compared with theoretical models that include various combinations of cold nuclear matter effects. From the non-prompt J/ψ production cross section, the b b ¯ production cross section at midrapidity, d σbb ¯/dy, and the total cross section extrapolated over full phase space, σbb ¯, are derived. [Figure not available: see fulltext.] © 2022, The Author(s).
|
|
| 47. |
- Acharya, S., et al.
(författare)
-
Inclusive quarkonium production in pp collisions at √s = 5.02 TeV
- 2023
-
Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 83:1
-
Tidskriftsartikel (refereegranskat)abstract
- This article reports on the inclusive production cross section of several quarkonium states, J / ψ, ψ(2 S) , Υ (1 S) , Υ (2 S) , and Υ (3 S) , measured with the ALICE detector at the LHC, in pp collisions at s=5.02 TeV. The analysis is performed in the dimuon decay channel at forward rapidity (2.5 < y< 4). The integrated cross sections and transverse-momentum (pT) and rapidity (y) differential cross sections for J / ψ, ψ(2 S) , Υ (1 S) , and the ψ(2 S) -to-J / ψ cross section ratios are presented. The integrated cross sections, assuming unpolarized quarkonia, are: σJ / ψ (pT< 20 GeV/c) = 5.88 ± 0.03 ± 0.34μb, σψ ( 2 S ) (pT< 12 GeV/c) = 0.87 ± 0.06 ± 0.10μb, σΥ ( 1 S ) (pT< 15 GeV/c) = 45.5 ± 3.9 ± 3.5 nb, σΥ (2 S) (pT< 15 GeV/c) = 22.4 ± 3.2 ± 2.7 nb, and σΥ (3 S) (pT< 15 GeV/c) = 4.9 ± 2.2 ± 1.0 nb, where the first (second) uncertainty is the statistical (systematic) one. For the first time, the cross sections of the three Υ states, as well as the ψ(2 S) one as a function of pTand y, are measured at s=5.02 TeV at forward rapidity. These measurements also significantly extend the J / ψpTreach and supersede previously published results. A comparison with ALICE measurements in pp collisions at s=2.76, 7, 8, and 13 TeV is presented and the energy dependence of quarkonium production cross sections is discussed. Finally, the results are compared with the predictions from several production models. © 2023, The Author(s).
|
|
| 48. |
- Acharya, S., et al.
(författare)
-
Investigating charm production and fragmentation via azimuthal correlations of prompt D mesons with charged particles in pp collisions at √s=13 TeV
- 2022
-
Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 82:4
-
Tidskriftsartikel (refereegranskat)abstract
- Angular correlations of heavy-flavour and charged particles in high-energy proton–proton collisions are sensitive to the production mechanisms of heavy quarks and to their fragmentation as well as hadronisation processes. The measurement of the azimuthal-correlation function of prompt D mesons with charged particles in proton–proton collisions at a centre-of-mass energy of s=13 TeV with the ALICE detector is reported, considering D , D +, and D ∗ + mesons in the transverse-momentum interval 3 < pT< 36 GeV/c at midrapidity (| y| < 0.5), and charged particles with pT> 0.3 GeV/c and pseudorapidity | η| < 0.8. This measurement has an improved precision and provides an extended transverse-momentum coverage compared to previous ALICE measurements at lower energies. The study is also performed as a function of the charged-particle multiplicity, showing no modifications of the correlation function with multiplicity within uncertainties. The properties and the transverse-momentum evolution of the near- and away-side correlation peaks are studied and compared with predictions from various Monte Carlo event generators. Among those considered, PYTHIA8 and POWHEG+PYTHIA8 provide the best description of the measured observables. The obtained results can provide guidance on tuning the generators. © 2022, The Author(s).
|
|
| 49. |
- Acharya, S., et al.
(författare)
-
Investigating the role of strangeness in baryon–antibaryon annihilation at the LHC
- 2022
-
Ingår i: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 829
-
Tidskriftsartikel (refereegranskat)abstract
- Annihilation dynamics plays a fundamental role in the baryon–antibaryon interaction (B–B‾) at low-energy and its strength and range are crucial in the assessment of possible baryonic bound states. Experimental data on annihilation cross sections are available for the p–p‾ system but not in the low relative momentum region. Data regarding the B–B‾ interaction with strange degrees of freedom are extremely scarce, hence the modeling of the annihilation contributions is mainly based on nucleon–antinucleon (N–N‾) results, when available. In this letter we present a measurement of the p–p‾, p–Λ‾⊕p‾–Λ and Λ–Λ‾ interaction using correlation functions in the relative momentum space in high-multiplicity triggered pp collisions at s=13 TeV recorded by ALICE at the LHC. In the p–p‾ system the couplings to the mesonic channels in different partial waves are extracted by adopting a coupled-channel approach with recent χEFT potentials. The inclusion of these inelastic channels provides good agreement with the data, showing a significant presence of the annihilation term down to zero momentum. Predictions obtained using the Lednický–Lyuboshits formula and scattering parameters obtained from heavy-ion collisions, hence mainly sensitive to elastic processes, are compared with the experimental p–Λ‾⊕p‾–Λ and Λ–Λ‾ correlations. The model describes the Λ–Λ‾ data and underestimates the p–Λ‾⊕p‾–Λ data in the region of momenta below 200 MeV/c. The observed deviation indicates a different contribution of annihilation channels to the two systems containing strange hadrons. © 2022 European Organization for Nuclear Research
|
|
| 50. |
- Acharya, S., et al.
(författare)
-
Investigation of K+K- interactions via femtoscopy in Pb-Pb collisions at sNN =2.76 TeV at the CERN Large Hadron Collider
- 2023
-
Ingår i: Physical Review C. - 2469-9985. ; 107:5
-
Tidskriftsartikel (refereegranskat)abstract
- Femtoscopic correlations of nonidentical charged kaons (K+K-) are studied in Pb-Pb collisions at a center-of-mass energy per nucleon-nucleon collision sNN=2.76 TeV by ALICE at the CERN Large Hadron Collider. One-dimensional K+K- correlation functions are analyzed in three centrality classes and eight intervals of particle-pair transverse momentum. The Lednický and Luboshitz interaction model used in the K+K- analysis includes the final-state Coulomb interactions between kaons and the final-state interaction through a0(980) and f0(980) resonances. The mass of f0(980) and coupling were extracted from the fit to K+K- correlation functions using the femtoscopic technique. The measured mass and width of the f0(980) resonance are consistent with other published measurements. The height of the φ(1020) meson peak present in the K+K- correlation function rapidly decreases with increasing source radius, qualitatively in agreement with an inverse volume dependence. A phenomenological fit to this trend suggests that the φ(1020) meson yield is dominated by particles produced directly from the hadronization of the system. The small fraction subsequently produced by final-state interactions could not be precisely quantified with data presented in this paper and will be assessed in future work. © 2023 CERN.
|
|
