{
  "abstract": "A precise measurement of prompt and non-prompt ${\\rm D}^{\\rm *+}$-meson spin alignment with respect to the helicity and production axes in proton-proton (pp) collisions at $\\sqrt{s} = 13.6$ TeV is presented, using data collected with the ALICE experiment at the LHC. The spin alignment is quantified by measuring the diagonal spin density matrix element $ρ_{\\rm 00}$ for ${\\rm D}^{\\rm *+}$ mesons at midrapidity ($|y|<0.8$). The measurement is performed in the transverse-momentum ($p_{\\rm T}$) range $3<p_{\\rm T}<100$ GeV/$c$ for prompt ${\\rm D}^{\\rm *+}$ mesons and $3<p_{\\rm T}<30$ GeV/$c$ for non-prompt ${\\rm D}^{\\rm *+}$ mesons, respectively. The measured $ρ_{\\rm 00}$ values for prompt ${\\rm D}^{\\rm *+}$ mesons are consistent with the unpolarised expectation of $1/3$ over the entire $p_{\\rm T}$ range, indicating no evidence of spin alignment. In contrast, $ρ_{\\rm 00}$ of non-prompt ${\\rm D}^{\\rm *+}$ mesons exhibit a deviation from $1/3$, consistent with expectations from weak beauty-hadron decays and well described by PYTHIA 8 simulations coupled with the EvtGen decay package. These results confirm and extend previous measurements, providing a precise baseline for future studies of ${\\rm D}^{\\rm *+}$ spin alignment in heavy-ion collisions.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.39713",
  "author_total": 1036,
  "authors": [
    {
      "name": "Dana Ali Hassan Abdallah"
    },
    {
      "name": "Ibrahim Jaser Abualrob"
    },
    {
      "name": "Shreyasi Acharya"
    },
    {
      "name": "Anil Berkay Adiguzel"
    },
    {
      "name": "Kshitij Agarwal"
    },
    {
      "name": "Gianluca Aglieri Rinella"
    },
    {
      "name": "Luca Aglietta"
    },
    {
      "name": "Neelima Agrawal"
    },
    {
      "name": "Zubayer Ahammed"
    },
    {
      "name": "Shakeel Ahmad"
    },
    {
      "name": "Zulkaida Akbar"
    },
    {
      "name": "Valentina Akishina"
    },
    {
      "name": "Mohammad Al-Turany"
    },
    {
      "name": "Bruno Alessandro"
    },
    {
      "name": "Abdul Rahman Alfarasyi"
    },
    {
      "name": "Jose Ruben Alfaro Molina"
    },
    {
      "name": "Bushra Ali"
    },
    {
      "name": "Andrea Alici"
    },
    {
      "name": "Johan Alme"
    },
    {
      "name": "Giacomo Alocco"
    },
    {
      "name": "Torsten Alt"
    },
    {
      "name": "Igor Altsybeev"
    },
    {
      "name": "Cristian Andrei"
    },
    {
      "name": "Nicodemos Andreou"
    },
    {
      "name": "Anton Andronic"
    },
    {
      "name": "Massimo Angeletti"
    },
    {
      "name": "Venelin Anguelov"
    },
    {
      "name": "Federico Antinori"
    },
    {
      "name": "Pietro Antonioli"
    },
    {
      "name": "Nicole Apadula"
    },
    {
      "name": "Harald Appelshaeuser"
    },
    {
      "name": "Silvia Arcelli"
    },
    {
      "name": "Roberta Arnaldi"
    },
    {
      "name": "Ionut Cristian Arsene"
    },
    {
      "name": "Mesut Arslandok"
    },
    {
      "name": "Muhammad Uzair Aslam"
    },
    {
      "name": "Andre Augustinus"
    },
    {
      "name": "Ralf Peter Averbeck"
    },
    {
      "name": "Mohd Danish Azmi"
    },
    {
      "name": "Byungyun Kong"
    },
    {
      "name": "Hitoshi Baba"
    },
    {
      "name": "Akash Raj John Babu"
    },
    {
      "name": "Angela Badala"
    },
    {
      "name": "Joonsuk Bae"
    },
    {
      "name": "Yunseul Bae"
    },
    {
      "name": "Yongwook Baek"
    },
    {
      "name": "Xiaozhi Bai"
    },
    {
      "name": "Raphaelle Marie Bailhache"
    },
    {
      "name": "Yoshini Bailung"
    },
    {
      "name": "Renu Bala"
    },
    {
      "name": "Alberto Baldisseri"
    },
    {
      "name": "Bartosz Balis"
    },
    {
      "name": "Shubham Bangalia"
    },
    {
      "name": "Koushik Barai"
    },
    {
      "name": "Veronika Barbasova"
    },
    {
      "name": "Francesco Barile"
    },
    {
      "name": "Luca Barioglio"
    },
    {
      "name": "Maria Barlou"
    },
    {
      "name": "Banajit Barman"
    },
    {
      "name": "Gergely Gabor Barnafoldi"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/6z7nn0sccy9wb.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.39713",
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  "language": "en",
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
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  "openalex": "W7215039413",
  "pdf_url": "https://arxiv.org/pdf/2609.39713",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-30",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/6z7nn0sccy9wb.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:49Z",
      "native_id": "hal-05781937",
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      "url": "https://hal.science/hal-05781937v1"
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      "native_id": "2609.39713",
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      "url": "https://arxiv.org/abs/2609.39713"
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  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:hep-ex",
      "subfield": "high-energy"
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    {
      "field": "physics",
      "origin": "arxiv:nucl-ex",
      "subfield": "nuclear"
    }
  ],
  "title": "Measurement of prompt and non-prompt ${\\rm D}^{\\rm *+}$-meson spin alignment in pp collisions at $\\sqrt{s}$ = 13.6 TeV$",
  "title_text": "Measurement of prompt and non-prompt D^*+-meson spin alignment in pp collisions at √s = 13.6 TeV$",
  "type": "preprint",
  "updated_at": "2026-10-30T12:25:49Z",
  "url": "https://research.draconitic.com/paper/6z7nn0sccy9wb",
  "venue": "HAL",
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}