Date

Disentangling sources of momentum fluctuations in Xe+Xe and Pb+Pb collisions with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Aakvaag, Erlend ; Abbott, Braden Keim ; et al.
Phys.Rev.Lett. 133 (2024) 252301, 2024.
Inspire Record 2806288 DOI 10.17182/hepdata.153671

High-energy nuclear collisions create a quark-gluon plasma, whose initial condition and subsequent expansion vary from event to event, impacting the distribution of the event-wise average transverse momentum ($P([p_{\mathrm{T}}])$). Distinguishing between contributions from fluctuations in the size of the nuclear overlap area (geometrical component) and other sources at fixed size (intrinsic component) presents a challenge. Here, these two components are distinguished by measuring the mean, variance, and skewness of $P([p_{\mathrm{T}}])$ in $^{208}$Pb+$^{208}$Pb and $^{129}$Xe+$^{129}$Xe collisions at $\sqrt{s_{{\mathrm{NN}}}} = 5.02$ and 5.44 TeV, respectively, using the ATLAS detector at the LHC. All observables show distinct changes in behavior in ultra-central collisions, where the geometrical variations are suppressed as the overlap area reaches its maximum. These results demonstrate a new technique to disentangle geometrical and intrinsic fluctuations, enabling constraints on initial condition and properties of the quark-gluon plasma, such as the speed of sound.

42 data tables

Data from Figure 1, panel a, $\left\langle[p_{T}]\right\rangle$ vs $N_{ch}$ for Pb+Pb collisions, 0.5 $ <p_{T}< $ 5 GeV/c, $|\eta|< $ 2.5

Data from Figure 1, panel b, $\left\langle[p_{T}]\right\rangle$ vs $N_{ch}$ for Pb+Pb collisions, 0.5 $ <p_{T}< $ 5 GeV/c, $|\eta|< $ 2.5

Data from Figure 1, panel b, $\left\langle[p_{T}]\right\rangle$ vs $N_{ch}$ for Xe+Xe collisions, 0.5 $ <p_{T}< $ 5 GeV/c, $|\eta|< $ 2.5

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Measurement of the production cross section of prompt $\Xi^0_{\rm c}$ baryons in p$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}}~=~5.02$ TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Agarwal, Apar ; et al.
Eur.Phys.J.C 85 (2025) 86, 2025.
Inspire Record 2789570 DOI 10.17182/hepdata.155330

The transverse momentum ($p_{\rm T}$) differential production cross section of the promptly produced charm-strange baryon $\Xi_{\rm c}^{0}$ (and its charge conjugate $\overline{\Xi_{\rm c}^{0}}$) is measured at midrapidity via its hadronic decay into ${\rm \pi^{+}}\Xi^{-}$ in p$-$Pb collisions at a centre-of-mass energy per nucleon$-$nucleon collision $\sqrt{s_{\mathrm{NN}}}~=~5.02$ TeV with the ALICE detector at the LHC. The $\Xi_{\rm c}^{0}$ nuclear modification factor ($R_{\rm pPb}$), calculated from the cross sections in pp and p$-$Pb collisions, is presented and compared with the $R_{\rm pPb}$ of $\Lambda_{\rm c}^{+}$ baryons. The ratios between the $p_{\rm T}$-differential production cross section of $\Xi_{\rm c}^{0}$ baryons and those of $\mathrm {D^0}$ mesons and $\Lambda_{\rm c}^{+}$ baryons are also reported and compared with results at forward and backward rapidity from the LHCb Collaboration. The measurements of the production cross section of prompt $\Xi^0_{\rm c}$ baryons are compared with a model based on perturbative QCD calculations of charm-quark production cross sections, which includes only cold nuclear matter effects in p$-$Pb collisions, and underestimates the measurement by a factor of about 50. This discrepancy is reduced when the data is compared with a model that includes string formation beyond leading-colour approximation or in which hadronisation is implemented via quark coalescence. The $p_{\rm T}$-integrated cross section of prompt $\Xi^0_{\rm c}$-baryon production at midrapidity extrapolated down to $p_{\rm T}$ = 0 is also reported. These measurements offer insights and constraints for theoretical calculations of the hadronisation process. Additionally, they provide inputs for the calculation of the charm production cross section in p$-$Pb collisions at midrapidity.

6 data tables

Prompt $\Xi_\mathrm{c}^0$ productions cross-section as a function of $p_\mathrm{T}$ in p–Pb collisions at $\sqrt{s_\mathrm{NN}} = 5.02$ TeV.

$\Xi_\mathrm{c}^0~R_\mathrm{pPb}$ as a function of $p_\mathrm{T}$ in p–Pb collisions at $\sqrt{s_\mathrm{NN}} = 5.02$ TeV.

$\Xi_\mathrm{c}^0/\mathrm{D}^0$ ratio as a function of $p_\mathrm{T}$ in p–Pb collisions at $\sqrt{s_\mathrm{NN}} = 5.02$ TeV.

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Investigating strangeness enhancement with multiplicity in pp collisions using angular correlations

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Agarwal, Apar ; et al.
JHEP 09 (2024) 204, 2024.
Inspire Record 2789572 DOI 10.17182/hepdata.154226

A study of strange hadron production associated with hard scattering processes and with the underlying event is conducted to investigate the origin of the enhanced production of strange hadrons in small collision systems characterised by large charged-particle multiplicities. For this purpose, the production of the single-strange meson ${\rm K^0_S}$ and the double-strange baryon $\Xi^{\pm}$ is measured, in each event, in the azimuthal direction of the highest-$p_{\rm T}$ particle (``trigger" particle), related to hard scattering processes, and in the direction transverse to it in azimuth, associated with the underlying event, in pp collisions at $\sqrt{s}=5.02$ TeV and $\sqrt{s}=13$ TeV using the ALICE detector at the LHC. The per-trigger yields of ${\rm K^0_S}$ and $\Xi^{\pm}$ are dominated by the transverse-to-leading production (i.e., in the direction transverse to the trigger particle), whose contribution relative to the toward-leading production is observed to increase with the event charged-particle multiplicity. The transverse-to-leading and the toward-leading $\Xi^{\pm}$/${\rm K^0_S}$ yield ratios increase with the multiplicity of charged particles, suggesting that strangeness enhancement with multiplicity is associated with both hard scattering processes and the underlying event. The relative production of $\Xi^{\pm}$ with respect to ${\rm K^0_S}$ is higher in transverse-to-leading processes over the whole multiplicity interval covered by the measurement. The ${\rm K}^{0}_{\rm{S}}$ and $\Xi^{\pm}$ per-trigger yields and yield ratios are compared with predictions of three different phenomenological models, namely PYTHIA 8.2 with the Monash tune, PYTHIA 8.2 with ropes and EPOS LHC. The comparison shows that none of them can quantitatively describe either the transverse-to-leading or the toward-leading yields of ${\rm K}^{0}_{\rm{S}}$ and $\Xi^{\pm}$.

18 data tables

Yields of $\rm K^{0}_\rm{S}$ per trigger particle per unit $\Delta\eta\Delta\varphi$ area in pp collisions at $\sqrt{s}=13$ TeV, as a function of the $\rm K^{0}_\rm{S}$ $p_\rm{T}$. Trigger particles are charged particles with $p_\rm{T}>3$ GeV/c. The trigger-particle-$\rm K^{0}_\rm{S}$ correlation is integrated in the ranges $-1.2<\Delta\eta<1.2$ and $-\pi/2<\Delta\varphi<3/2\pi$.

Transverse-to-leading yields of $\rm K^{0}_\rm{S}$ per trigger particle per unit $\Delta\eta\Delta\varphi$ area in pp collisions at $\sqrt{s}=13$ TeV, as a function of the $\rm K^{0}_\rm{S}$ $p_\rm{T}$. Trigger particles are charged particles with $p_\rm{T}>3$ GeV/c. The trigger-particle-$\rm K^{0}_\rm{S}$ correlation is integrated in the ranges $0.86<|\Delta\eta|<1.2$ and $0.96<\Delta\varphi<1.8$.

Toward-leading yields of $\rm K^{0}_\rm{S}$ per trigger particle per unit $\Delta\eta\Delta\varphi$ area in pp collisions at $\sqrt{s}=13$ TeV, as a function of the $\rm K^{0}_\rm{S}$ $p_\rm{T}$. Trigger particles are charged particles with $p_\rm{T}>3$ GeV/c. The trigger-particle-$\rm K^{0}_\rm{S}$ correlation is integrated in the ranges $|\Delta\eta|<0.86$ and $|\Delta\varphi|<1.1$.

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Charm fragmentation fractions and ${\rm c\overline{c}}$ cross section in p$-$Pb collisions at $\sqrt{s_{\rm NN}}=5.02$ TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Agarwal, Apar ; et al.
Eur.Phys.J.C 84 (2024) 1286, 2024.
Inspire Record 2789567 DOI 10.17182/hepdata.154667

The total charm-quark production cross section per unit of rapidity $\mathrm{d}\sigma({\rm c\overline{c}})/\mathrm{d}y$, and the fragmentation fractions of charm quarks to different charm-hadron species $f(\mathrm{c}\rightarrow {\rm h_{c}})$, are measured for the first time in p$-$Pb collisions at $\sqrt{s_\mathrm{NN}} = 5.02$ TeV at midrapidity ($-0.96<y<0.04$ in the centre-of-mass frame) using data collected by ALICE at the CERN LHC. The results are obtained based on all the available measurements of prompt production of ground-state charm-hadron species: $\mathrm{D}^{0}$, $\mathrm{D}^{+}$, $\mathrm{D}_\mathrm{s}^{+}$, and $\mathrm{J/\psi}$ mesons, and $\Lambda_\mathrm{c}^{+}$ and $\Xi_{\rm c}^{0}$ baryons. The resulting cross section is $\mathrm{d}\sigma({\rm c\overline{c}})/\mathrm{d}y =219.6 \pm 6.3\;(\mathrm{stat.}) {\;}_{-11.8}^{+10.5}\;(\mathrm{syst.}) {\;}_{-2.9}^{+8.3}\;(\mathrm{extr.})\pm 5.4\;(\mathrm{BR})\pm 4.6\;(\mathrm{lumi.}) \pm 19.5\;(\text{rapidity shape})+15.0\;(\Omega_{\rm c}^{0})$ mb, which is consistent with a binary scaling of pQCD calculations from pp collisions. The measured fragmentation fractions are compatible with those measured in pp collisions at $\sqrt{s} = 5.02$ and $13$ TeV, showing an increase in the relative production rates of charm baryons with respect to charm mesons in pp and p$-$Pb collisions compared with $\mathrm{e^{+}e^{-}}$ and $\mathrm{e^{-}p}$ collisions. The $p_\mathrm{T}$-integrated nuclear modification factor of charm quarks, $R_\mathrm{pPb}({\rm c\overline{c}})= 0.91 \pm 0.04\;{\rm (stat.)}{}^{+0.08}_{-0.09}\;{\rm (syst.)}{}^{+0.05}_{-0.03}\;{\rm (extr.)}{}\pm 0.03\;{\rm (lumi.)}$, is found to be consistent with unity and with theoretical predictions including nuclear modifications of the parton distribution functions.

4 data tables

The $p_\mathrm{T}$-integrated rapidity-differential cross sections for all measured charm-hadron species at midrapidity in p-Pb collisions at $\sqrt{s_\mathrm{NN}} = 5.02$ TeV.

The fragmentation fractions $f(\mathrm{c}\rightarrow\mathrm{h}_{\mathrm{c}})$ of charm hadrons in p-Pb collisions at $\sqrt{s_\mathrm{NN}} = 5.02$ TeV.

The total $\mathrm{c\overline{c}}$ production cross section at midrapidity in p-Pb collisions at $\sqrt{s_\mathrm{NN}} = 5.02$ TeV.

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Measurement of beauty-quark production in pp collisions at $\sqrt{s}=13$ TeV via non-prompt D mesons

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Agarwal, Apar ; et al.
JHEP 10 (2024) 110, 2024.
Inspire Record 2762380 DOI 10.17182/hepdata.154893

The $p_{\rm T}$-differential production cross sections of non-prompt ${\rm D^0}$, ${\rm D^+}$, and ${\rm D_s^+}$ mesons originating from beauty-hadron decays are measured in proton$-$proton collisions at a centre-of-mass energy $\sqrt{s}=13$ TeV. The measurements are performed at midrapidity, $|y| < 0.5$, with the data sample collected by ALICE from 2016 to 2018. The results are in agreement with predictions from several perturbative QCD calculations. The fragmentation fraction of beauty quarks to strange mesons divided by the one to non-strange mesons, $f_{\rm{s}}/(f_{\rm{u}} + f_{\rm{d}})$, is found to be $0.114 \pm 0.016~{\rm (stat.)} \pm 0.006~{\rm (syst.)} \pm 0.003~{\rm (BR)} \pm 0.003~{\rm (extrap.)}$. This value is compatible with previous measurements at lower centre-of-mass energies and in different collision systems in agreement with the assumption of universality of fragmentation functions. In addition, the dependence of the non-prompt D meson production on the centre-of-mass energy is investigated by comparing the results obtained at $\sqrt{s} = 5.02$ and 13 TeV, showing a hardening of the non-prompt D-meson $p_{\rm T}$-differential production cross section at higher $\sqrt{s}$. Finally, the ${\rm b\overline{b}}$ production cross section per unit of rapidity at midrapidity is calculated from the non-prompt ${\rm D^0}$, ${\rm D^+}$, ${\rm D_s^+}$, and $\Lambda_{\rm c}^+$ hadron measurements, obtaining ${\rm d}\sigma/{\rm d}y = 75.2\pm 3.2~(\mathrm{stat.}) \pm 5.2~(\mathrm{syst.})^{+12.3}_{-3.2} ~(\mathrm{extrap.})\text{ } \rm \mu b \;.$

11 data tables

$p_{\mathrm{T}}$-differential non-prompt $\mathrm{D}^{0}$ production cross section at midrapidity ($|y|<0.5$) in pp collisions at $\sqrt{s}$ = 13 TeV Branching ratio of $\mathrm{D}^{0}\rightarrow\mathrm{K}^-\pi^+$: $(3.95 \pm 0.03)\%$. Global relative uncertainty on BR: $0.8\%$ Global relative uncertainty on luminosity: $1.6\%$

$p_{\mathrm{T}}$-differential non-prompt $\mathrm{D}^{+}$ production cross section at midrapidity ($|y|<0.5$) in pp collisions at $\sqrt{s}$ = 13 TeV Branching ratio of $\mathrm{D}^{+}\rightarrow\mathrm{K}^-\pi^+\pi^+$: $(9.38 \pm 0.16)\%$. Global relative uncertainty on BR: $1.7\%$ Global relative uncertainty on luminosity: $1.6\%$

$p_{\mathrm{T}}$-differential $\mathrm{D}^{+}_\mathrm{s}$ production cross section at midrapidity ($|y|<0.5$) in pp collisions at $\sqrt{s}$ = 13 TeV Branching ratio of $\mathrm{D}^{+}_\mathrm{s}\rightarrow\phi\pi^+\rightarrow\mathrm{K}^+\mathrm{K}^-\pi^+$: $(2.22 \pm 0.06)\%$. Global relative uncertainty on BR: $2.7\%$ Global relative uncertainty on luminosity: $1.6\%$

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Charged-particle production as a function of the relative transverse activity classifier in pp, p$-$Pb, and Pb$-$Pb collisions at the LHC

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Aglieri Rinella, Gianluca ; et al.
JHEP 01 (2024) 056, 2024.
Inspire Record 2709103 DOI 10.17182/hepdata.146104

Measurements of charged-particle production in pp, p$-$Pb, and Pb$-$Pb collisions in the toward, away, and transverse regions with the ALICE detector are discussed. These regions are defined event-by-event relative to the azimuthal direction of the charged trigger particle, which is the reconstructed particle with the largest transverse momentum ($p_{\mathrm{T}}^{\rm trig}$) in the range $8<p_{\mathrm{T}}^{\rm trig}<15$ GeV$/c$. The toward and away regions contain the primary and recoil jets, respectively; both regions are accompanied by the underlying event (UE). In contrast, the transverse region perpendicular to the direction of the trigger particle is dominated by the so-called UE dynamics, and includes also contributions from initial- and final-state radiation. The relative transverse activity classifier, $R_{\mathrm{T}}=N_{\mathrm{ch}}^{\mathrm{T}}/\langle N_{\mathrm{ch}}^{\mathrm{T}}\rangle$, is used to group events according to their UE activity, where $N_{\mathrm{ch}}^{\mathrm{T}}$ is the charged-particle multiplicity per event in the transverse region and $\langle N_{\mathrm{ch}}^{\mathrm{T}}\rangle$ is the mean value over the whole analysed sample. The energy dependence of the $R_{\mathrm{T}}$ distributions in pp collisions at $\sqrt{s}=2.76$, 5.02, 7, and 13 TeV is reported, exploring the Koba-Nielsen-Olesen (KNO) scaling properties of the multiplicity distributions. The first measurements of charged-particle $p_{\rm T}$ spectra as a function of $R_{\mathrm{T}}$ in the three azimuthal regions in pp, p$-$Pb, and Pb$-$Pb collisions at $\sqrt{s_{\rm NN}}=5.02$ TeV are also reported. Data are compared with predictions obtained from the event generators PYTHIA 8 and EPOS LHC. This set of measurements is expected to contribute to the understanding of the origin of collective-like effects in small collision systems (pp and p$-$Pb).

28 data tables

$R_\mathrm{T}$ distribution using events with trigger particles $5<p_\mathrm{T}^\mathrm{trig}<40~\mathrm{GeV}/c$ in the pseudorapidity range of $|\eta|<0.8$ and with $p_\mathrm{T}>0.5~\mathrm{GeV}/c$ in pp collisions at $\sqrt{s}=2.76~\mathrm{TeV}$

$R_\mathrm{T}$ distribution using events with trigger particles $5<p_\mathrm{T}^\mathrm{trig}<40~\mathrm{GeV}/c$ in the pseudorapidity range of $|\eta|<0.8$ and with $p_\mathrm{T}>0.5~\mathrm{GeV}/c$ in pp collisions at $\sqrt{s}=5.02~\mathrm{TeV}$

$R_\mathrm{T}$ distribution using events with trigger particles $5<p_\mathrm{T}^\mathrm{trig}<40~\mathrm{GeV}/c$ in the pseudorapidity range of $|\eta|<0.8$ and with $p_\mathrm{T}>0.5~\mathrm{GeV}/c$ in pp collisions at $\sqrt{s}=7~\mathrm{TeV}$

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Prompt and non-prompt J$/\psi$ production at midrapidity in Pb$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Aglieri Rinella, Gianluca ; et al.
JHEP 02 (2024) 066, 2024.
Inspire Record 2692201 DOI 10.17182/hepdata.146723

The transverse momentum ($p_{\rm T}$) and centrality dependence of the nuclear modification factor $R_{\rm AA}$ of prompt and non-prompt J$/\psi$, the latter originating from the weak decays of beauty hadrons, have been measured by the ALICE collaboration in Pb$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV. The measurements are carried out through the ${\rm e}^{+}{\rm e}^{-}$ decay channel at midrapidity ($|y| < 0.9$) in the transverse momentum region $1.5 < p_{\rm T} < 10$ GeV/$c$. Both prompt and non-prompt J$/\psi$ measurements indicate a significant suppression for $p_{\rm T} >$ 5 GeV/$c$, which becomes stronger with increasing collision centrality. The results are consistent with similar LHC measurements in the overlapping $p_{\rm T}$ intervals, and cover the kinematic region down to $p_{\rm T}$ = 1.5 GeV/$c$ at midrapidity, not accessible by other LHC experiments. The suppression of prompt J$/\psi$ in central and semicentral collisions exhibits a decreasing trend towards lower transverse momentum, described within uncertainties by models implementing J$/\psi$ production from recombination of c and $\overline{\rm c}$ quarks produced independently in different partonic scatterings. At high transverse momentum, transport models including quarkonium dissociation are able to describe the suppression for prompt J$/\psi$. For non-prompt J$/\psi$, the suppression predicted by models including both collisional and radiative processes for the computation of the beauty-quark energy loss inside the quark$-$gluon plasma is consistent with measurements within uncertainties.

16 data tables

Non-prompt J/$\psi$ fraction as a function of transverse momentum in Pb-Pb at 5.02 TeV, centrality 0-10%

Non-prompt J/$\psi$ fraction as a function of transverse momentum in Pb-Pb at 5.02 TeV, centrality 10-30%

Non-prompt J/$\psi$ fraction as a function of transverse momentum in Pb-Pb at 5.02 TeV, centrality 30-50%

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Probing the Chiral Magnetic Wave with charge-dependent flow measurements in Pb-Pb collisions at the LHC

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Aglieri Rinella, Gianluca ; et al.
JHEP 12 (2023) 067, 2023.
Inspire Record 2692198 DOI 10.17182/hepdata.145839

The Chiral Magnetic Wave (CMW) phenomenon is essential to provide insights into the strong interaction in QCD, the properties of the quark-gluon plasma, and the topological characteristics of the early universe, offering a deeper understanding of fundamental physics in high-energy collisions. Measurements of the charge-dependent anisotropic flow coefficients are studied in Pb-Pb collisions at center-of-mass energy per nucleon-nucleon collision $\sqrt{s_{\mathrm{NN}}}=$ 5.02 TeV to probe the CMW. In particular, the slope of the normalized difference in elliptic ($v_{2}$) and triangular ($v_{3}$) flow coefficients of positively and negatively charged particles as a function of their event-wise normalized number difference, is reported for inclusive and identified particles. The slope $r_{3}^{\rm Norm}$ is found to be larger than zero and to have a magnitude similar to $r_{2}^{\rm Norm}$, thus pointing to a large background contribution for these measurements. Furthermore, $r_{2}^{\rm Norm}$ can be described by a blast wave model calculation that incorporates local charge conservation. In addition, using the event shape engineering technique yields a fraction of CMW ($f_{\rm CMW}$) contribution to this measurement which is compatible with zero. This measurement provides the very first upper limit for $f_{\rm CMW}$, and in the 10-60% centrality interval it is found to be 26% (38%) at 95% (99.7%) confidence level.

15 data tables

Normalized $\Delta\it{v}_{2}$ slope of charged hadrons as a function of centrality in Pb-Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV.

Normalized $\Delta\it{v}_{2}$ slope of kaons as a function of centrality in Pb-Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV.

Normalized $\Delta\it{v}_{2}$ slope of pions as a function of centrality in Pb-Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV.

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Charm production and fragmentation fractions at midrapidity in pp collisions at $\sqrt{s} = 13$ TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Aglieri Rinella, Gianluca ; et al.
JHEP 12 (2023) 086, 2023.
Inspire Record 2697877 DOI 10.17182/hepdata.145759

Measurements of the production cross sections of prompt ${\rm D^0}$, ${\rm D^+}$, ${\rm D^{\ast +}}$, ${\rm D_s^+}$, ${\rm \Lambda_{c}^{+}}$, and ${\rm \Xi_{c}^{+}}$ charm hadrons at midrapidity in proton$-$proton collisions at $\sqrt{s}=13$ TeV with the ALICE detector are presented. The D-meson cross sections as a function of transverse momentum ($p_{\rm T}$) are provided with improved precision and granularity. The ratios of $p_{\rm T}$-differential meson production cross sections based on this publication and on measurements at different rapidity and collision energy provide a constraint on gluon parton distribution functions at low values of Bjorken-$x$ ($10^{-5}-10^{-4}$). The measurements of ${\rm \Lambda_{c}^{+}}$ (${\rm \Xi_{c}^{+}}$) baryon production extend the measured $p_{\rm T}$ intervals down to $p_{\rm T}=0(3)$~GeV$/c$. These measurements are used to determine the charm-quark fragmentation fractions and the ${\rm c\overline{c}}$ production cross section at midrapidity ($|y|<0.5$) based on the sum of the cross sections of the weakly-decaying ground-state charm hadrons ${\rm D^0}$, ${\rm D^+}$, ${\rm D_s^+}$, ${\rm \Lambda_{c}^{+}}$, ${\rm \Xi_{c}^{0}}$ and, for the first time, ${\rm \Xi_{c}^{+}}$, and of the strongly-decaying J/$psi$ mesons. The first measurements of ${\rm \Xi_{c}^{+}}$ and ${\rm \Sigma_{c}^{0,++}}$ fragmentation fractions at midrapidity are also reported. A significantly larger fraction of charm quarks hadronising to baryons is found compared to e$^+$e$^-$ and ep collisions. The ${\rm c\overline{c}}$ production cross section at midrapidity is found to be at the upper bound of state-of-the-art perturbative QCD calculations.

39 data tables

$p_{\mathrm{T}}$-differential $\mathrm{D}^{0}$ production cross section at midrapidity ($|y|<0.5$) in pp collisions at $\sqrt{s}$ = 13 TeV Branching ratio of $\mathrm{D}^{0}\rightarrow\mathrm{K}^-\pi^+$: $(3.95 \pm 0.03)\%$. Global relative uncertainty on BR: $0.8\%$ Global relative uncertainty on luminosity: $1.6\%$

$p_{\mathrm{T}}$-differential $\mathrm{D}^{+}$ production cross section at midrapidity ($|y|<0.5$) in pp collisions at $\sqrt{s}$ = 13 TeV Branching ratio of $\mathrm{D}^{+}\rightarrow\mathrm{K}^-\pi^+\pi^+$: $(9.38 \pm 0.16)\%$. Global relative uncertainty on BR: $1.7\%$ Global relative uncertainty on luminosity: $1.6\%$

$p_{\mathrm{T}}$-differential $\mathrm{D}^{+}$ production cross section at midrapidity ($|y|<0.5$) in pp collisions at $\sqrt{s}$ = 13 TeV Branching ratio of $\mathrm{D}^{*+}\rightarrow\mathrm{D}^0(\rightarrow\mathrm{K}^-\pi^+)\pi^+$: $(2.67 \pm 0.03)\%$. Global relative uncertainty on BR: $1.1\%$ Global relative uncertainty on luminosity: $1.6\%$

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Measurement of Non-prompt $\rm D^0$-meson Elliptic Flow in Pb-Pb Collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Aglieri Rinella, Gianluca ; et al.
Eur.Phys.J.C 83 (2023) 1123, 2023.
Inspire Record 2681666 DOI 10.17182/hepdata.145800

The elliptic flow ($v_2$) of $\rm D^0$ mesons from beauty-hadron decays (non-prompt $\rm D^0$) was measured in midcentral (30-50%) Pb-Pb collisions at a centre-of-mass energy per nucleon pair $\sqrt{s_{\rm NN}}$ = 5.02 TeV with the ALICE detector at the LHC. The $\rm D^0$ mesons were reconstructed at midrapidity ($|y|<0.8$) from their hadronic decay $\mathrm{D^0 \to K^-\pi^+}$, in the transverse momentum interval $2 < p_{\rm T} < 12$ GeV/$c$. The result indicates a positive $v_2$ for non-prompt $\rm D^0$ mesons with a significance of 2.7$\sigma$. The non-prompt $\rm D^0$-meson $v_2$ is lower than that of prompt non-strange D mesons with 3.2$\sigma$ significance in $2 < p_{\rm T} < 8$ GeV/$c$, and compatible with the $v_2$ of beauty-decay electrons. Theoretical calculations of beauty-quark transport in a hydrodynamically expanding medium describe the measurement within uncertainties.

1 data table

$p_\mathrm{T}$-differential elliptic flow coefficient $v_2$ of non-prompt $\mathrm{D^0}$ mesons in the 30-50% centrality class in Pb-Pb collisions at $\sqrt{s_\mathrm{NN}}=5.02~\mathrm{TeV}$.