Event-by-event fluctuations of the event-wise mean transverse momentum, $\langle p_{\mathrm{T}}\rangle$, of charged particles produced in proton$-$proton (pp) collisions at $\sqrt{s}$ = 5.02 TeV, Xe$-$Xe collisions at $\sqrt{s_{\mathrm{NN}}} =$ 5.44 TeV, and Pb$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}} =$ 5.0 TeV are studied using the ALICE detector based on the integral correlator $\langle\langle Δp_{\rm T}Δp_{\rm T}\rangle\rangle $. The correlator strength is found to decrease monotonically with increasing produced charged-particle multiplicity measured at midrapidity in all three systems. In Xe$-$Xe and Pb$-$Pb collisions, the multiplicity dependence of the correlator deviates significantly from a simple power-law scaling as well as from the predictions of the HIJING and AMPT models. The observed deviation from power-law scaling is expected from transverse radial flow in semicentral to central Xe$-$Xe and Pb$-$Pb collisions. In pp collisions, the correlation strength is also studied by classifying the events based on the transverse spherocity, $S_0$, of the particle production at midrapidity, used as a proxy for the presence of a pronounced back-to-back jet topology. Low-spherocity (jetty) events feature a larger correlation strength than those with high spherocity (isotropic). The strength and multiplicity dependence of jetty and isotropic events are well reproduced by calculations with the PYTHIA 8 and EPOS LHC models.
Normalized transverse momentum correlator, $\sqrt{ \langle\langle \Delta p_{{\rm T}1}\Delta p_{{\rm T}2} \rangle\rangle }$$/\langle\langle p_{\rm T} \rangle\rangle $, as a function of the charged-particle multiplicity density, $\langle{\rm d}N_{\rm ch}/{\rm d}\eta \rangle$, in pp collisions at $\sqrt{s}$ = 5.02 TeV.
Normalized transverse momentum correlator, $\sqrt{ \langle\langle \Delta p_{{\rm T}1}\Delta p_{{\rm T}2} \rangle\rangle }$$/\langle\langle p_{\rm T} \rangle\rangle $, as a function of the charged-particle multiplicity density, $\langle{\rm d}N_{\rm ch}/{\rm d}\eta \rangle$, in Pb--Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV.
Normalized transverse momentum correlator, $\sqrt{ \langle\langle \Delta p_{{\rm T}1}\Delta p_{{\rm T}2} \rangle\rangle }$$/\langle\langle p_{\rm T} \rangle\rangle $, as a function of the charged-particle multiplicity density, $\langle{\rm d}N_{\rm ch}/{\rm d}\eta \rangle$, in Xe--Xe collisions at $\sqrt{s_{\rm NN}}$ = 5.44 TeV.
The first measurements of proton emission accompanied by neutron emission in the electromagnetic dissociation (EMD) of $^{208}$Pb nuclei in the ALICE experiment at the LHC are presented. The EMD protons and neutrons emitted at very forward rapidities are detected by the proton and neutron Zero Degree Calorimeters of the ALICE experiment. The emission cross sections of zero, one, two, and three protons accompanied by at least one neutron were measured in ultraperipheral $^{208}$Pb--$^{208}$Pb collisions at a center-of-mass energy per nucleon pair $\sqrt{s_{\rm NN}}=5.02$ TeV. The 0p and 3p cross sections are described by the RELDIS model within their measurement uncertainties, while the 1p and 2p cross sections are underestimated by the model by 17-25%. According to this model, these 0p, 1p, 2p, and 3p cross sections are associated, respectively, with the production of various isotopes of Pb, Tl, Hg, and Au in the EMD of $^{208}$Pb. The cross sections of the emission of a single proton accompanied by the emission of one, two, or three neutrons in EMD were also measured. The data are significantly overestimated by the RELDIS model, which predicts that the (1p,1n), (1p,2n), and (1p,3n) cross sections are very similar to the cross sections for the production of the thallium isotopes $^{206,205,204}$Tl.
Measured cross sections of the emission of a given number of protons k accompanied by at least one neutron i in UPC of Pb nuclei.
Measured cross sections of the emission of a given number of neutrons i accompanied by a single proton in UPC of Pb nuclei.
Differential two-particle normalized cumulants ($R_2$) and transverse momentum correlations ($P_2$) are measured as a function of the relative pseudorapidity and azimuthal angle difference $( \Delta \eta, \Delta \varphi )$ of charged particle pairs in minimum bias pp collisions at $\sqrt{\textit{s}}$ = 13 TeV. The measurements use charged hadrons in the pseudorapidity region of $|\eta| < 0.8$ and the transverse momentum range 0.2 $< \textit{p}_{\mathrm T} < $ 2.0 $\mathrm{GeV}/\textit{c}$ in order to focus on soft multiparticle interactions and to complement prior measurements of these correlation functions in p-Pb and Pb-Pb collisions. The correlation functions are reported for both unlike-sign and like-sign pairs and their charge-independent and charge-dependent combinations. Both the $R_2$ and $P_2$ measured in pp collisions exhibit features qualitatively similar to those observed in p-Pb and Pb-Pb collisions. The $\Delta\eta$ and $\Delta\varphi$ root mean square widths of the near-side peak of the correlation functions are evaluated and compared with those observed in p-Pb and Pb-Pb collisions and show smooth evolution with the multiplicity of charged particles produced in the collision. The comparison of the measured correlation functions with predictions from PYTHIA8 shows that this model qualitatively captures their basic structure and characteristics but feature important differences. In addition, the $R_2^{\rm CD}$ is used to determine the charge balance function of hadrons produced within the detector acceptance of the measurements. The integral of the balance function is found to be compatible with those reported by a previous measurement in Pb-Pb collisions. These results, which are sensitive to the interplay between the underlying event and mini-jets in pp collisions, establish a baseline for heavy-ion collisions.
Correlation functions $R_2^{\rm US}$ of charged hadrons measured in minimum bias pp collisions at $\sqrt{s}=13\;\text{TeV}$. Charged hadrons are selected in the range $0.2 < p_{\rm T} < 2.0$ GeV/$c$ and with pseudorapidity $|\eta| < 0.8$.
Correlation functions $R_2^{\rm LS}$ of charged hadrons measured in minimum bias pp collisions at $\sqrt{s}=13\;\text{TeV}$. Charged hadrons are selected in the range $0.2 < p_{\rm T} < 2.0$ GeV/$c$ and with pseudorapidity $|\eta| < 0.8$.
Correlation functions $P_2^{\rm US}$ of charged hadrons measured in minimum bias pp collisions at $\sqrt{s}=13\;\text{TeV}$. Charged hadrons are selected in the range $0.2 < p_{\rm T} < 2.0$ GeV/$c$ and with pseudorapidity $|\eta| < 0.8$.
The ALICE Collaboration presents a new suite of jet substructure measurements in Pb-Pb and pp collisions at a center-of-mass energy per nucleon pair $\sqrt{s}_{\rm NN} = 5.02$ TeV. These measurements provide access to the internal structure of jets via the momentum and angle of their constituents, probing how the quark--gluon plasma modifies jets, an effect known as jet quenching. Jet grooming additionally removes soft wide-angle radiation to enhance perturbative accuracy and reduce experimental uncertainties. We report the groomed and ungroomed jet mass $m_{\rm jet}$ and jet angularities $\lambda_\alpha^\kappa$ using $\kappa=1$ and $\alpha>0$. Charged-particle jets are reconstructed at midrapidity using the anti-$k_\mathrm{T}$ algorithm with resolution parameter $R = 0.2$. A narrowing of the jet mass and angularity distributions in Pb-Pb collisions with respect to pp is observed and is enhanced for groomed results, confirming modification of the jet core. By using consistent jet definitions and kinematic cuts between the mass and angularities for the first time, previous inconsistencies in the interpretation of quenching measurements are resolved, rectifying a hurdle for understanding how jet quenching arises from first principles and highlighting the importance of a well-controlled baseline. These results are compared with a variety of theoretical models of jet quenching, providing constraints on jet energy-loss mechanisms in the quark--gluon plasma.
Jet angularity $\lambda_{\alpha}$ for $\alpha = 1$. $40<p_{\mathrm{T}}^{\mathrm{ch jet}}<60$. For the "trkeff" and "generator" systematic uncertainty sources, the signed systematic uncertainty breakdowns ($\pm$ vs. $\mp$), denote correlation across bins (both within this table, and across tables). For the remaining sources ("unfolding", "random_mass") no correlation information is specified ($\pm$ is always used).
Jet angularity $\lambda_{\alpha}$ for $\alpha = 1.5$. $40<p_{\mathrm{T}}^{\mathrm{ch jet}}<60$ GeV/$c$. For the "trkeff" and "generator" systematic uncertainty sources, the signed systematic uncertainty breakdowns ($\pm$ vs. $\mp$), denote correlation across bins (both within this table, and across tables). For the remaining sources ("unfolding", "random_mass") no correlation information is specified ($\pm$ is always used).
Jet angularity $\lambda_{\alpha}$ for $\alpha = 2$. $40<p_{\mathrm{T}}^{\mathrm{ch jet}}<60$ GeV/$c$. For the "trkeff" and "generator" systematic uncertainty sources, the signed systematic uncertainty breakdowns ($\pm$ vs. $\mp$), denote correlation across bins (both within this table, and across tables). For the remaining sources ("unfolding", "random_mass") no correlation information is specified ($\pm$ is always used).
A measurement of the top quark pair ($\mathrm{t\bar{t}}$) production cross section in proton-proton collisions at a centre-of-mass energy of 5.02 TeV is presented. The data were collected at the LHC in autumn 2017, in dedicated runs with low-energy and low-intensity conditions with respect to the default configuration, and correspond to an integrated luminosity of 302 pb$^{-1}$. The measurement is performed using events with one electron or muon, and multiple jets, at least one of them being identified as originating from a b quark (b tagged). Events are classified based on the number of all reconstructed jets and of b-tagged jets. Multivariate analysis techniques are used to enhance the separation between the signal and backgrounds. The measured cross section is 62.5 $\pm$ 1.6 (stat) $^{+2.6}_{-2.5}$ (syst) $\pm$ 1.2 (lumi) pb. A combination with the result in the dilepton channel based on the same data set yields a value of 62.3 $\pm$ 1.5 (stat) $\pm$ 2.4 (syst) $\pm$ 1.2 (lumi) pb, to be compared with the standard model prediction of 69.5 $^{+3.5}_{-3.7}$ pb at next-to-next-to-leading order in perturbative quantum chromodynamics.
Distributions for data and expected signal and background contributions of the most discriminating input variables (\ensuremath{\Delta R_\mathrm{med}(\mathrm{j,j')}}) used for the random forest training, in the 3j1b category, before the maximum likelihood fit. The vertical error bars represent the statistical uncertainty in the data, and the shaded band the uncertainty in the prediction. All uncertainties considered in the analysis are included in the uncertainty band. The lower panels show the data-to-prediction ratio. The first and last bins in each distribution include underflow and overflow events, respectively.
Distributions for data and expected signal and background contributions of the most discriminating input variables (\ensuremath{\mathit{m}(\mathrm{u},\mathrm{u'})}) used for the random forest training, in the 3j1b category, before the maximum likelihood fit. The vertical error bars represent the statistical uncertainty in the data, and the shaded band the uncertainty in the prediction. All uncertainties considered in the analysis are included in the uncertainty band. The lower panels show the data-to-prediction ratio. The first and last bins in each distribution include underflow and overflow events, respectively.
Distributions for data and expected signal and background contributions of the MVA score for the e + jets channel in the 3j1b category, before the maximum likelihood fit. The vertical error bars represent the statistical uncertainty in the data, and the shaded band the uncertainty in the prediction. All uncertainties considered in the analysis are included in the uncertainty band. The lower panels show the data-to-prediction ratio. The first and last bins in each distribution include underflow and overflow events, respectively.
In this Letter, the first evidence of the ${}^4_{\bar{\Lambda}}\overline{\mathrm{He}}$ antihypernucleus is presented, along with the first measurement at the LHC of the production of (anti)hypernuclei with mass number $A=4$, specifically (anti)${}^4_{\Lambda}\mathrm{H}$ and (anti)${}^4_{\Lambda}\mathrm{He}$. In addition, the antiparticle-to-particle ratios for both hypernuclei (${}^4_{\bar{\Lambda}}\overline{\mathrm{H}}$ / ${}^4_{\Lambda}\mathrm{H}$~and ${}^4_{\bar{\Lambda}}\overline{\mathrm{He}}$ / ${}^4_{\Lambda}\mathrm{He}$) are shown, which are sensitive to the baryochemical potential of the strongly-interacting matter created in heavy-ion collisions. The results are obtained from a data sample of central Pb--Pb collisions, collected during the 2018 LHC data-taking at a center-of-mass energy per nucleon pair of $\sqrt{s_{\mathrm{NN}}} = $ 5.02 TeV. The yields measured for the average of the charge-conjugated states are found to be $[0.78 \; \pm \; 0.19 \; \mathrm{(stat.)} \; \pm \; 0.17 \; \mathrm{(syst.)}] \times 10^{-6}$ for the (anti)${}^4_{\Lambda}\mathrm{H}$ and $[1.08 \; \pm \; 0.34 \; \mathrm{(stat.)} \; \pm \; 0.20 \; \mathrm{(syst.)}] \times 10^{-6}$ for the (anti)${}^4_{\Lambda}\mathrm{He}$, and the measured antiparticle-to-particle ratios are in agreement with unity. The presence of (anti)${}^4_{\Lambda}\mathrm{H}$ and (anti)${}^4_{\Lambda}\mathrm{He}$ excited states is expected to strongly enhance the production yield of these hypernuclei. The yield values exhibit a combined deviation of 3.3$\sigma$ from the theoretical ground-state-only expectation, while the inclusion of the excited states in the calculations leads to an agreement within 0.6$\sigma$ with the present measurements. Additionally, the measured (anti)${}^4_{\Lambda}\mathrm{H}$ and (anti)${}^4_{\Lambda}\mathrm{He}$ masses are compatible with the world-average values within the uncertainties.
average pT-integrated yield of particle and antiparticle of both analyzed (anti)hypernuclei in Pb-Pb collisions in 0-10% V0M centrality class
mass measurement of both analyzed (anti)hypernuclei in Pb-Pb collisions in 0-10% V0M centrality class
antiparticle-to-particle ratio of the analyzed (anti)hypernuclei in Pb-Pb collisions in 0-10% V0M centrality class
The ALICE Collaboration reports measurements of the large relative transverse momentum ($k_{\text{T}}$) component of jet substructure in pp and Pb$-$Pb collisions at center-of-mass energy per nucleon pair $\sqrt{s_{\text{NN}}}=5.02$ TeV. Enhancement in the yield of such large-$k_{\text{T}}$ emissions in head-on Pb$-$Pb collisions is predicted to arise from partonic scattering with quasi-particles of the quark-gluon plasma. The analysis utilizes charged-particle jets reconstructed by the anti-$k_{\text{T}}$ algorithm with resolution parameter $R=0.2$ in the transverse-momentum interval $60 < p_{\text{T,ch jet}} < 80$ GeV/$c$. The soft drop and dynamical grooming algorithms are used to identify high transverse momentum splittings in the jet shower. Comparison of measurements in Pb$-$Pb and pp collisions shows medium-induced narrowing, corresponding to yield suppression of high-$k_{\text{T}}$ splittings, in contrast to the expectation of yield enhancement due to quasi-particle scattering. The measurements are compared to theoretical model calculations incorporating jet modification due to jet-medium interactions ("jet quenching"), both with and without quasi-particle scattering effects. These measurements provide new insight into the underlying mechanisms and theoretical modeling of jet quenching.
Groomed relative transverse momentum, $k_{\text{T,g}}$, spectra measured in pp collisions. $60 < p_{\text{T,ch jet}}^{\text{}} < 80\:\text{GeV}/c$, Dynamical grooming $a = 1.0$ For the "trk eff" and "generator" systematic uncertainty sources, the signed systematic uncertainty breakdowns ($\pm$ vs. $\mp$) denote correlation across bins. For the remaining sources ("unfold"), no correlation information is specified (i.e. $\pm$ is always used). In the publication, the quadrature sum of all sources of systematic uncertainty is reported, neglecting the sign information reported here.
Groomed relative transverse momentum, $k_{\text{T,g}}$, spectra measured in 30--50% Pb-Pb collisions. $60 < p_{\text{T,ch jet}}^{\text{}} < 80\:\text{GeV}/c$, Dynamical grooming $a = 1.0$ For the "trk eff" and "generator" systematic uncertainty sources, the signed systematic uncertainty breakdowns ($\pm$ vs. $\mp$) denote correlation across bins. For the remaining sources ("unfold,bkg,non_closure"), no correlation information is specified (i.e. $\pm$ is always used). In the publication, the quadrature sum of all sources of systematic uncertainty is reported, neglecting the sign information reported here.
Groomed relative transverse momentum, $k_{\text{T,g}}$, spectra measured in 0--10% Pb-Pb collisions. $60 < p_{\text{T,ch jet}}^{\text{}} < 80\:\text{GeV}/c$, Dynamical grooming $a = 1.0$ For the "trk eff" and "generator" systematic uncertainty sources, the signed systematic uncertainty breakdowns ($\pm$ vs. $\mp$) denote correlation across bins. For the remaining sources ("unfold,bkg,non_closure"), no correlation information is specified (i.e. $\pm$ is always used). In the publication, the quadrature sum of all sources of systematic uncertainty is reported, neglecting the sign information reported here.
The ALICE Collaboration at the CERN LHC has measured the inclusive production cross section of isolated photons at midrapidity as a function of the photon transverse momentum ($p_{\rm T}^{\gamma}$), in Pb$-$Pb collisions in different centrality intervals, and in pp collisions, at centre-of-momentum energy per nucleon pair of $\sqrt{s_{\rm NN}}=5.02$ TeV. The photon transverse momentum range is between 10-14 and 40-140 GeV/$c$, depending on the collision system and on the Pb$-$Pb centrality class. The result extends to lower $p_{\rm T}^{\gamma}$ than previously published results by the ATLAS and CMS experiments at the same collision energy. The covered pseudorapidity range is $|\eta^{\gamma}| <0.67$. The isolation selection is based on a charged particle isolation momentum threshold $p_{\rm T}^{\rm iso,~ch} = 1.5$ GeV/$c$ within a cone of radii $R=0.2$ and $0.4$. The nuclear modification factor is calculated and found to be consistent with unity in all centrality classes, and also consistent with the HG-PYTHIA model, which describes the event selection and geometry biases that affect the centrality determination in peripheral Pb$-$Pb collisions. The measurement is compared to next-to-leading order perturbative QCD calculations and to the measurements of isolated photons and Z$^0$ bosons from the CMS experiment, which are all found to be in agreement.
Isolated-photon differential cross section measured in pp and Pb$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02~\mathrm{TeV}$ for five Pb$-$Pb centrality classes for $R=0.2$. Note that the Pb$-$Pb data in the first five columns is scaled by $\langle N_{\mathrm{coll}} \rangle$, unlike in the figure in the paper where the theory was scaled by $\langle N_{\mathrm{coll}} \rangle$. Last two columns correspond to theory NLO pQCD calculations with JETPHOX, for pp (PDF) and Pb$-$Pb (nPDF) collisions calculated for the 0$-$100% centrality class. Data statistical and systematic uncertainties are provided. The theory scale and PDF uncertainties are provided. The data normalisation uncertainties are provided in the paper.
Isolated-photon differential cross section measured in pp and Pb$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02~\mathrm{TeV}$ for five Pb$-$Pb centrality classes for $R=0.4$. Note that the Pb$-$Pb data in the first five columns is scaled by $\langle N_{\mathrm{coll}} \rangle$, unlike in the figure in the paper where the theory was scaled by $\langle N_{\mathrm{coll}} \rangle$. Last two columns correspond to theory NLO pQCD calculations with JETPHOX, for pp (PDF) and Pb$-$Pb (nPDF) collisions calculated for the 0$-$100% centrality class. Data statistical and systematic uncertainties are provided. The theory scale and PDF uncertainties are provided. The data normalisation uncertainties are provided in the paper.
Ratio of isolated-photon cross section measured with $R=0.4$ over $R=0.2$ for Pb$-$Pb and pp collisions at $\sqrt{s_{\mathrm{NN}}}=5.02~\mathrm{TeV}$. Each column for each Pb$-$Pb collisions centrality class and for pp collisions. The last two columns for the NLO pQCD JETPHOX calculations for pp (PDF) and Pb$-$Pb (nPDF) collisions. Data statistical and systematic uncertainties are provided. The theory statiscal (Monte Carlo approach) and PDF uncertainties are provided.
In ultra-relativistic heavy ion collisions at the LHC, each nucleus acts a sources of high-energy real photons that can scatter off the opposing nucleus in ultra-peripheral photonuclear ($\gamma+A$) collisions. Hard scattering processes initiated by the photons in such collisions provide a novel method for probing nuclear parton distributions in a kinematic region not easily accessible to other measurements. ATLAS has measured production of dijet and multi-jet final states in ultra-peripheral Pb+Pb collisions at $\sqrt{s_{\text{NN}}} = 5.02$ TeV using a data set recorded in 2018 with an integrated luminosity of 1.72 $\text{nb}^{-1}$. Photonuclear final states are selected by requiring a rapidity gap in the photon direction; this selects events where one of the outgoing nuclei remains intact. Jets are reconstructed using the anti-$k_\text{t}$ algorithm with radius parameter, $R = 0.4$. Triple-differential cross-sections, unfolded for detector response, are measured and presented using two sets of kinematic variables. The first set consists of the total transverse momentum ($H_\text{T}$),rapidity, and mass of the jet system. The second set uses $H_\text{T}$ and particle-level nuclear and photon parton momentum fractions, $x_\text{A}$ and $z_{\gamma}$, respectively. The results are compared with leading-order (LO) perturbative QCD calculations of photonuclear jet production cross-sections, where all LO predictions using existing fits fall below the data in the shadowing region. More detailed theoretical comparisons will allow these results to strongly constrain nuclear parton distributions, and these data provide results from the LHC directly comparable to early physics results at the planned Electron-Ion Collider.
The fraction of photonuclear jet events passing the fiducial requirements in which the photon-emitting nucleus does not break up as a function of \zg. The systematic uncertainties are not symmetrized, and correlations in uncertainties are neglected for both the total systematic uncertainty and statistical uncertainty.
Fully unfolded triple-differential cross-sections as a function of $H_\text{T}$, $y_\text{jets}$, and $m_\text{jets}$. Systematic uncertainties are decomposed into symmetrized nuisance parameters, where parameters labelled "Corr" are fully correlated bin-to-bin, while parameters labelled "Uncorr" should be treated as un-correlated bin-to-bin. These cross-sections are not corrected for the effects of additional nuclear break-up. Values for the total fiducial cross-section in each bin are reported with full statistical and systematic uncertainties. Fractions of the total bin volume occupied by the fiducial region, fractions of the total cross-section in that bin satisfying fiducial requirements, and mean bin values for each axis variable are derived from Pythia 8 Monte Carlo and reported as well. For more details on these quantities, see Appendix B.
Fully unfolded triple-differential cross-sections as a function of $H_\text{T}$, $x_\text{A}$, and $z_{\gamma}$. Systematic uncertainties are decomposed into symmetrized nuisance parameters, where parameters labelled "Corr" are fully correlated bin-to-bin, while parameters labelled "Uncorr" should be treated as un-correlated bin-to-bin. These cross-sections are not corrected for the effects of additional nuclear break-up. Values for the total fiducial cross-section in each bin are reported with full statistical and systematic uncertainties. Fractions of the total bin volume occupied by the fiducial region, fractions of the total cross-section in that bin satisfying fiducial requirements, and mean bin values for each axis variable are derived from Pythia 8 Monte Carlo and reported as well. For more details on these quantities, see Appendix B.
The production cross sections of B$^0_\mathrm{s}$ and B$^+$ mesons are reported in proton-proton (pp) collisions recorded by the CMS experiment at the CERN LHC with a center-of-mass energy of 5.02 TeV. The data sample corresponds to an integrated luminosity of 302 pb$^{-1}$. The cross sections are based on measurements of the B$^0_\mathrm{s}$$\to$ J/$ψ(μ^+μ^-)ϕ$(1020) (K$^+$K$^-$) and B$^+$$\to$ J/$ψ(μ^+μ^-)$K$^+$ decay channels. Results are presented in the transverse momentum ($p_\mathrm{T}$) range 7-50 GeV/$c$ and the rapidity interval $\lvert y \rvert$$\lt$ 2.4 for the B mesons. The measured $p_\mathrm{T}$-differential cross sections of B$^+$ and B$^0_\mathrm{s}$ in pp collisions are well described by fixed-order plus next-to-leading logarithm perturbative quantum chromodynamics calculations. Using previous PbPb collision measurements at the same nucleon-nucleon center-of-mass energy, the nuclear modification factors, $R_\mathrm{AA}$, of the B mesons are determined. For $p_\mathrm{T}$$\lt$ 10 GeV/$c$, both mesons are found to be suppressed in PbPb collisions (with $R_\mathrm{AA}$ values significantly below unity), with less suppression observed for the B$^0_\mathrm{s}$ mesons. In this $p_\mathrm{T}$ range, the $R_\mathrm{AA}$ values for the B$^+$ mesons are consistent with those for inclusive charged hadrons and D$^0$ mesons. Below 10 GeV/$c$, both B$^+$ and B$^0_\mathrm{s}$ are found to be less suppressed than either inclusive charged hadrons or D$^0$ mesons, with the B$^0_\mathrm{s}$$R_\mathrm{AA}$ value consistent with unity. The $R_\mathrm{AA}$ values found for the B$^+$ and B$^0_\mathrm{s}$ are compared to theoretical calculations, providing constraints on the mechanism of bottom quark energy loss and hadronization in the quark-gluon plasma, the hot and dense matter created in ultrarelativistic heavy ion collisions.
The B+ meson $p_{\rm{T}}$-dependent production cross section in pp collisions. The measurment was carried out inside a fiducial region respecting ($p_{\rm{T}}$<10 & 1.5<|y|<2.4) and ($p_{\rm{T}}$>10 & |y|<2.4). The luminosity is 302.3 pb^{-1}.
The Bs meson $p_{\rm{T}}$-dependent production cross section in pp collisions. The measurment was carried out inside a fiducial region respecting (pT<10 & 1.5<|y|<2.4) and ($p_{\rm{T}}$>10 & |y|<2.4). The luminosity is 302.3 pb^{-1}.
The B+ meson $p_{\rm{T}}$-dependent RAA in PpPp. The measurment was carried out inside a fiducial region respecting ($p_{\rm{T}}$<10 & 1.5<|y|<2.4) and ($p_{\rm{T}}$>10 & |y|<2.4).
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