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  5. The ALICE Collaboration reports measurements of the semi-inclusive distribution of charged-particle jets recoiling from a high transverse momentum (highpT) charged hadron, inppand central Pb-Pb collisions at center-of-mass energy per nucleon–nucleon collisionsNN=5.02TeV. The large uncorrelated background in central Pb-Pb collisions is corrected using a data-driven statistical approach which enables precise measurement of recoil jet distributions over a broad range inpT,chjetand jet resolution parameterR. Recoil jet yields are reported forR=0.2, 0.4, and 0.5 in the range7<pT,chjet<140 GeV/candπ/2<Δφ<π, whereΔφis the azimuthal angular separation between hadron trigger and recoil jet. The low-pT,chjetreach of the measurement explores unique phase space for studying jet quenching, the interaction of jets with the quark–gluon plasma generated in high-energy nuclear collisions. Comparison ofpT,chjetdistributions fromppand central Pb-Pb collisions probes medium-induced jet energy loss and intra-jet broadening, while comparison of their acoplanarity distributions explores in-medium jet scattering and medium response. The measurements are compared to theoretical calculations incorporating jet quenching.

    <supplementary-material><permissions><copyright-statement>©2024 CERN, for the ALICE Collaboration</copyright-statement><copyright-year>2024</copyright-year><copyright-holder>CERN</copyright-holder></permissions></supplementary-material></sec> </div> <a href='#' class='show open-abstract' style='margin-left:10px;'>more »</a> <a href='#' class='hide close-abstract' style='margin-left:10px;'>« less</a> <div class="actions" style="padding-left:10px;"> <span class="reader-count"> Free, publicly-accessible full text available July 1, 2025</span> </div> </div><div class="clearfix"></div> </div> </li> <li> <div class="article item document" itemscope itemtype="http://schema.org/TechArticle"> <div class="item-info"> <div class="title"> <a href="https://par.nsf.gov/biblio/10554971-observation-medium-induced-yield-enhancement-acoplanarity-broadening-low-pt-jets-from-measurements-pp-central-pb-pb-collisions-snn" itemprop="url"> <span class='span-link' itemprop="name">Observation of Medium-Induced Yield Enhancement and Acoplanarity Broadening of Low- pT Jets from Measurements in pp and Central Pb-Pb Collisions at sNN=5.02  TeV</span> </a> </div> <div> <strong> <a class="misc external-link" href="https://doi.org/10.1103/PhysRevLett.133.022301" target="_blank" title="Link to document DOI">https://doi.org/10.1103/PhysRevLett.133.022301  <span class="fas fa-external-link-alt"></span></a> </strong> </div> <div class="metadata"> <span class="authors"> <span class="author" itemprop="author">Acharya, S</span> <span class="sep">; </span><span class="author" itemprop="author">Adamová, D</span> <span class="sep">; </span><span class="author" itemprop="author">Aglieri_Rinella, G</span> <span class="sep">; </span><span class="author" itemprop="author">Agnello, M</span> <span class="sep">; </span><span class="author" itemprop="author">Agrawal, N</span> <span class="sep">; </span><span class="author" itemprop="author">Ahammed, Z</span> <span class="sep">; </span><span class="author" itemprop="author">Ahmad, S</span> <span class="sep">; </span><span class="author" itemprop="author">Ahn, S U</span> <span class="sep">; </span><span class="author" itemprop="author">Ahuja, I</span> <span class="sep">; </span><span class="author" itemprop="author">Akindinov, A</span> <span class="sep">; </span><span class="author">et al</span></span> <span class="year">( <time itemprop="datePublished" datetime="2024-07-01">July 2024</time> , Physical Review Letters) </span> </div> <div style="cursor: pointer;-webkit-line-clamp: 5;" class="abstract" itemprop="description"> <p>The ALICE Collaboration reports the measurement of semi-inclusive distributions of charged-particle jets recoiling from a high transverse momentum (high<math display='inline'><mrow><msub><mrow><mi>p</mi></mrow><mrow><mi mathvariant='normal'>T</mi></mrow></msub></mrow></math>) hadron trigger in proton-proton and central Pb-Pb collisions at<math display='inline'><mrow><msqrt><mrow><msub><mrow><mi>s</mi></mrow><mrow><mi>NN</mi></mrow></msub></mrow></msqrt><mo>=</mo><mn>5.02</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></mrow></math>. A data-driven statistical method is used to mitigate the large uncorrelated background in central Pb-Pb collisions. Recoil jet distributions are reported for jet resolution parameter<math display='inline'><mi>R</mi><mo>=</mo><mn>0.2</mn></math>, 0.4, and 0.5 in the range<math display='inline'><mrow><mn>7</mn><mo><</mo><msub><mrow><mi>p</mi></mrow><mrow><mi mathvariant='normal'>T</mi><mo>,</mo><mtext>jet</mtext></mrow></msub><mo><</mo><mn>140</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi><mo>/</mo><mi>c</mi></mrow></math>and trigger-recoil jet azimuthal separation<math display='inline'><mrow><mi>π</mi><mo>/</mo><mn>2</mn><mo><</mo><mrow><mi mathvariant='normal'>Δ</mi><mi>φ</mi></mrow><mo><</mo><mi>π</mi></mrow></math>. The measurements exhibit a marked medium-induced jet yield enhancement at low<math display='inline'><msub><mi>p</mi><mi mathvariant='normal'>T</mi></msub></math>and at large azimuthal deviation from<math display='inline'><mrow><mrow><mi mathvariant='normal'>Δ</mi><mi>φ</mi></mrow><mo>∼</mo><mi>π</mi></mrow></math>. The enhancement is characterized by its dependence on<math display='inline'><mi mathvariant='normal'>Δ</mi><mi>φ</mi></math>, which has a slope that differs from zero by<math display='inline'><mrow><mn>4.7</mn><mi>σ</mi></mrow></math>. Comparisons to model calculations incorporating different formulations of jet quenching are reported. These comparisons indicate that the observed yield enhancement arises from the response of the QGP medium to jet propagation.</p> <sec><title/><supplementary-material><permissions><copyright-statement>© 2024 CERN, for the ALICE Collaboration</copyright-statement><copyright-year>2024</copyright-year><copyright-holder>CERN</copyright-holder></permissions></supplementary-material></sec> </div> <a href='#' class='show open-abstract' style='margin-left:10px;'>more »</a> <a href='#' class='hide close-abstract' style='margin-left:10px;'>« less</a> <div class="actions" style="padding-left:10px;"> <span class="reader-count"> Free, publicly-accessible full text available July 1, 2025</span> </div> </div><div class="clearfix"></div> </div> </li> <li> <div class="article item document" itemscope itemtype="http://schema.org/TechArticle"> <div class="item-info"> <div class="title"> <a href="https://par.nsf.gov/biblio/10514236-observation-abnormal-suppression-f0-production-ppb-collisions-snn-tev" itemprop="url"> <span class='span-link' itemprop="name">Observation of abnormal suppression of f0(980) production in p–Pb collisions at sNN = 5.02 TeV</span> </a> </div> <div> <strong> <a class="misc external-link" href="https://doi.org/10.1016/j.physletb.2024.138665" target="_blank" title="Link to document DOI">https://doi.org/10.1016/j.physletb.2024.138665  <span class="fas fa-external-link-alt"></span></a> </strong> </div> <div class="metadata"> <span class="authors"> <span class="author" itemprop="author">Acharya, S</span> <span class="sep">; </span><span class="author" itemprop="author">Adamová, D</span> <span class="sep">; </span><span class="author" itemprop="author">Aglieri_Rinella, G</span> <span class="sep">; </span><span class="author" itemprop="author">Agnello, M</span> <span class="sep">; </span><span class="author" itemprop="author">Agrawal, N</span> <span class="sep">; </span><span class="author" itemprop="author">Ahammed, Z</span> <span class="sep">; </span><span class="author" itemprop="author">Ahmad, S</span> <span class="sep">; </span><span class="author" itemprop="author">Ahn, SU</span> <span class="sep">; </span><span class="author" itemprop="author">Ahuja, I</span> <span class="sep">; </span><span class="author" itemprop="author">Akindinov, A</span> <span class="sep">; </span><span class="author">et al</span></span> <span class="year">( <time itemprop="datePublished" datetime="2024-06-01">June 2024</time> , Physics Letters B) </span> </div> <div class="actions" style="padding-left:10px;"> <span class="reader-count"> Free, publicly-accessible full text available June 1, 2025</span> </div> </div><div class="clearfix"></div> </div> </li> <li> <div class="article item document" itemscope itemtype="http://schema.org/TechArticle"> <div class="item-info"> <div class="title"> <a href="https://par.nsf.gov/biblio/10554975-systematic-study-flow-vector-fluctuations-snn-tev-pb-pb-collisions" itemprop="url"> <span class='span-link' itemprop="name">Systematic study of flow vector fluctuations in sNN=5.02 TeV Pb-Pb collisions</span> </a> </div> <div> <strong> <a class="misc external-link" href="https://doi.org/10.1103/PhysRevC.109.065202" target="_blank" title="Link to document DOI">https://doi.org/10.1103/PhysRevC.109.065202  <span class="fas fa-external-link-alt"></span></a> </strong> </div> <div class="metadata"> <span class="authors"> <span class="author" itemprop="author">Acharya, S</span> <span class="sep">; </span><span class="author" itemprop="author">Adamová, D</span> <span class="sep">; </span><span class="author" itemprop="author">Agarwal, A</span> <span class="sep">; </span><span class="author" itemprop="author">Aglieri_Rinella, G</span> <span class="sep">; </span><span class="author" itemprop="author">Aglietta, L</span> <span class="sep">; </span><span class="author" itemprop="author">Agnello, M</span> <span class="sep">; </span><span class="author" itemprop="author">Agrawal, N</span> <span class="sep">; </span><span class="author" itemprop="author">Ahammed, Z</span> <span class="sep">; </span><span class="author" itemprop="author">Ahmad, S</span> <span class="sep">; </span><span class="author" itemprop="author">Ahn, S U</span> <span class="sep">; </span><span class="author">et al</span></span> <span class="year">( <time itemprop="datePublished" datetime="2024-06-01">June 2024</time> , Physical Review C) </span> </div> <div style="cursor: pointer;-webkit-line-clamp: 5;" class="abstract" itemprop="description"> <p>Measurements of the<math><msub><mi>p</mi><mi mathvariant='normal'>T</mi></msub></math>-dependent flow vector fluctuations in Pb–Pb collisions at<math><mrow><msqrt><msub><mi>s</mi><mi>NN</mi></msub></msqrt><mo>=</mo><mn>5.02</mn><mspace width='0.16em'/><mi>TeV</mi></mrow></math>using azimuthal correlations with the ALICE experiment at the Large Hadron Collider are presented. A four-particle correlation approach [ALICE Collaboration, ] is used to quantify the effects of flow angle and magnitude fluctuations separately. This paper extends previous studies to additional centrality intervals and provides measurements of the<math><msub><mi>p</mi><mi mathvariant='normal'>T</mi></msub></math>-dependent flow vector fluctuations at<math><mrow><msqrt><msub><mi>s</mi><mi>NN</mi></msub></msqrt><mo>=</mo><mn>5.02</mn><mspace width='0.16em'/><mi>TeV</mi></mrow></math>with two-particle correlations. Significant<math><msub><mi>p</mi><mi mathvariant='normal'>T</mi></msub></math>-dependent fluctuations of the<math><msub><mover accent='true'><mi>V</mi><mo>⃗</mo></mover><mn>2</mn></msub></math>flow vector in Pb–Pb collisions are found across different centrality ranges, with the largest fluctuations of up to<math><mrow><mo>∼</mo><mn>15</mn><mo>%</mo></mrow></math>being present in the 5% most central collisions. In parallel, no evidence of significant<math><msub><mi>p</mi><mi mathvariant='normal'>T</mi></msub></math>-dependent fluctuations of<math><msub><mover accent='true'><mi>V</mi><mo>⃗</mo></mover><mn>3</mn></msub></math>or<math><msub><mover accent='true'><mi>V</mi><mo>⃗</mo></mover><mn>4</mn></msub></math>is found. Additionally, evidence of flow angle and magnitude fluctuations is observed with more than<math><mrow><mn>5</mn><mi>σ</mi></mrow></math>significance in central collisions. These observations in<math><mtext>Pb–Pb</mtext></math>collisions indicate where the classical picture of hydrodynamic modeling with a common symmetry plane breaks down. This has implications for hard probes at high<math><msub><mi>p</mi><mi mathvariant='normal'>T</mi></msub></math>, which might be biased by<math><msub><mi>p</mi><mi mathvariant='normal'>T</mi></msub></math>-dependent flow angle fluctuations of at least 23% in central collisions. Given the presented results, existing theoretical models should be reexamined to improve our understanding of initial conditions, quark–gluon plasma properties, and the dynamic evolution of the created system.</p> <sec><title/><supplementary-material><permissions><copyright-statement>©2024 CERN, for the ALICE Collaboration</copyright-statement><copyright-year>2024</copyright-year><copyright-holder>CERN</copyright-holder></permissions></supplementary-material></sec> </div> <a href='#' class='show open-abstract' style='margin-left:10px;'>more »</a> <a href='#' class='hide close-abstract' style='margin-left:10px;'>« less</a> <div class="actions" style="padding-left:10px;"> <span class="reader-count"> Free, publicly-accessible full text available June 1, 2025</span> </div> </div><div class="clearfix"></div> </div> </li> <li> <div class="article item document" itemscope itemtype="http://schema.org/TechArticle"> <div class="item-info"> <div class="title"> <a href="https://par.nsf.gov/biblio/10514233-light-flavor-particle-production-high-multiplicity-pp-collisions-sqrt-textrm-tev-function-transverse-spherocity" itemprop="url"> <span class='span-link' itemprop="name">Light-flavor particle production in high-multiplicity pp collisions at $$ \sqrt{\textrm{s}} $$ = 13 TeV as a function of transverse spherocity</span> </a> </div> <div> <strong> <a class="misc external-link" href="https://doi.org/10.1007/JHEP05(2024)184" target="_blank" title="Link to document DOI">https://doi.org/10.1007/JHEP05(2024)184  <span class="fas fa-external-link-alt"></span></a> </strong> </div> <div class="metadata"> <span class="authors"> <span class="author" itemprop="author">Acharya, S</span> <span class="sep">; </span><span class="author" itemprop="author">Adamová, D</span> <span class="sep">; </span><span class="author" itemprop="author">Aglieri_Rinella, G</span> <span class="sep">; </span><span class="author" itemprop="author">Agnello, M</span> <span class="sep">; </span><span class="author" itemprop="author">Agrawal, N</span> <span class="sep">; </span><span class="author" itemprop="author">Ahammed, Z</span> <span class="sep">; </span><span class="author" itemprop="author">Ahmad, S</span> <span class="sep">; </span><span class="author" itemprop="author">Ahn, S U</span> <span class="sep">; </span><span class="author" itemprop="author">Ahuja, I</span> <span class="sep">; </span><span class="author" itemprop="author">Akindinov, A</span> <span class="sep">; </span><span class="author">et al</span></span> <span class="year">( <time itemprop="datePublished" datetime="2024-05-01">May 2024</time> , Journal of High Energy Physics) </span> </div> <div style="cursor: pointer;-webkit-line-clamp: 5;" class="abstract" itemprop="description"> <title>A<sc>bstract</sc>

    Results on the transverse spherocity dependence of light-flavor particle production (π, K, p,ϕ, K*0,$$ {\textrm{K}}_{\textrm{S}}^0 $$KS0, Λ, Ξ) at midrapidity in high-multiplicity pp collisions at$$ \sqrt{s} $$s= 13 TeV were obtained with the ALICE apparatus. The transverse spherocity estimator$$ \left({S}_{\textrm{O}}^{p_{\textrm{T}}=1}\right) $$SOpT=1categorizes events by their azimuthal topology. Utilizing narrow selections on$$ {S}_{\textrm{O}}^{p_{\textrm{T}}=1} $$SOpT=1, it is possible to contrast particle production in collisions dominated by many soft initial interactions with that observed in collisions dominated by one or more hard scatterings. Results are reported for two multiplicity estimators covering different pseudorapidity regions. The$$ {S}_{\textrm{O}}^{p_{\textrm{T}}=1} $$SOpT=1estimator is found to effectively constrain the hardness of the events when the midrapidity (|η| < 0.8) estimator is used.

    The production rates of strange particles are found to be slightly higher for soft isotropic topologies, and severely suppressed in hard jet-like topologies. These effects are more pronounced for hadrons with larger mass and strangeness content, and observed when the topological selection is done within a narrow multiplicity interval. This demonstrates that an important aspect of the universal scaling of strangeness enhancement with final-state multiplicity is that high-multiplicity collisions are dominated by soft, isotropic processes. On the contrary, strangeness production in events with jet-like processes is significantly reduced.

    The results presented in this article are compared with several QCD-inspired Monte Carlo event generators. Models that incorporate a two-component phenomenology, either through mechanisms accounting for string density, or thermal production, are able to describe the observed strangeness enhancement as a function of$$ {S}_{\textrm{O}}^{p_{\textrm{T}}=1} $$SOpT=1.

     
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    Free, publicly-accessible full text available May 1, 2025
  6. A<sc>bstract</sc>

    The production yields of the Σ(1385)±and Ξ(1530)0resonances are measured in pp collisions at$$ \sqrt{s} $$s= 13 TeV with ALICE. The measurements are performed as a function of the charged-particle multiplicity ⟨dNch/dη⟩, which is related to the energy density produced in the collision. The results include transverse momentum (pT) distributions,pT-integrated yields, mean transverse momenta of Σ(1385)±and Ξ(1530)0, as well as ratios of thepT-integrated resonance yields relative to yields of other hadron species. The Σ(1385)±±and Ξ(1530)0±yield ratios are consistent with the trend of the enhancement of strangeness production from low to high multiplicity pp collisions, which was previously observed for strange and multi-strange baryons. The yield ratio between the measured resonances and the long-lived baryons with the same strangeness content exhibits a hint of a mild increasing trend at low multiplicity, despite too large uncertainties to exclude the flat behaviour. The results are compared with predictions from models such as EPOS-LHC and PYTHIA 8 with Rope shoving. The latter provides the best description of the multiplicity dependence of the Σ(1385)±and Ξ(1530)0production in pp collisions at$$ \sqrt{s} $$s= 13 TeV.

     
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    Free, publicly-accessible full text available May 1, 2025