PreprintCC BY 4.0HAL
Measurement of prompt and non-prompt D*+-meson spin alignment in pp collisions at √s = 13.6 TeV$
Abstract
A precise measurement of prompt and non-prompt D*+-meson spin alignment with respect to the helicity and production axes in proton-proton (pp) collisions at √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 ρ00 for D*+ mesons at midrapidity (|y|<0.8). The measurement is performed in the transverse-momentum (pT) range 3<pT<100 GeV/c for prompt D*+ mesons and 3<pT<30 GeV/c for non-prompt D*+ mesons, respectively. The measured ρ00 values for prompt D*+ mesons are consistent with the unpolarised expectation of 1/3 over the entire pT range, indicating no evidence of spin alignment. In contrast, ρ00 of non-prompt D*+ 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 D*+ spin alignment in heavy-ion collisions.
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BibTeX
@misc{abdallah2026measurement,
title = {{Measurement of prompt and non-prompt $\rm D^\rm *+$-meson spin alignment in pp collisions at $\sqrts$ = 13.6 TeV$}},
author = {Dana Ali Hassan Abdallah and Ibrahim Jaser Abualrob and Shreyasi Acharya and Anil Berkay Adiguzel and Kshitij Agarwal and Gianluca Aglieri Rinella and Luca Aglietta and Neelima Agrawal and Zubayer Ahammed and Shakeel Ahmad and Zulkaida Akbar and Valentina Akishina and Mohammad Al-Turany and Bruno Alessandro and Abdul Rahman Alfarasyi and Jose Ruben Alfaro Molina and Bushra Ali and Andrea Alici and Johan Alme and Giacomo Alocco and Torsten Alt and Igor Altsybeev and Cristian Andrei and Nicodemos Andreou and Anton Andronic and Massimo Angeletti and Venelin Anguelov and Federico Antinori and Pietro Antonioli and Nicole Apadula and Harald Appelshaeuser and Silvia Arcelli and Roberta Arnaldi and Ionut Cristian Arsene and Mesut Arslandok and Muhammad Uzair Aslam and Andre Augustinus and Ralf Peter Averbeck and Mohd Danish Azmi and Byungyun Kong and Hitoshi Baba and Akash Raj John Babu and Angela Badala and Joonsuk Bae and Yunseul Bae and Yongwook Baek and Xiaozhi Bai and Raphaelle Marie Bailhache and Yoshini Bailung and Renu Bala and Alberto Baldisseri and Bartosz Balis and Shubham Bangalia and Koushik Barai and Veronika Barbasova and Francesco Barile and Luca Barioglio and Maria Barlou and Banajit Barman and Gergely Gabor Barnafoldi},
howpublished = {HAL},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.39713},
eprint = {2609.39713},
archivePrefix = {arXiv},
url = {https://hal.science/hal-05781937v1},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Measurement of prompt and non-prompt D^*+-meson spin alignment in pp collisions at √s = 13.6 TeV$
AU - Dana Ali Hassan Abdallah
AU - Ibrahim Jaser Abualrob
AU - Shreyasi Acharya
AU - Anil Berkay Adiguzel
AU - Kshitij Agarwal
AU - Gianluca Aglieri Rinella
AU - Luca Aglietta
AU - Neelima Agrawal
AU - Zubayer Ahammed
AU - Shakeel Ahmad
AU - Zulkaida Akbar
AU - Valentina Akishina
AU - Mohammad Al-Turany
AU - Bruno Alessandro
AU - Abdul Rahman Alfarasyi
AU - Jose Ruben Alfaro Molina
AU - Bushra Ali
AU - Andrea Alici
AU - Johan Alme
AU - Giacomo Alocco
AU - Torsten Alt
AU - Igor Altsybeev
AU - Cristian Andrei
AU - Nicodemos Andreou
AU - Anton Andronic
AU - Massimo Angeletti
AU - Venelin Anguelov
AU - Federico Antinori
AU - Pietro Antonioli
AU - Nicole Apadula
AU - Harald Appelshaeuser
AU - Silvia Arcelli
AU - Roberta Arnaldi
AU - Ionut Cristian Arsene
AU - Mesut Arslandok
AU - Muhammad Uzair Aslam
AU - Andre Augustinus
AU - Ralf Peter Averbeck
AU - Mohd Danish Azmi
AU - Byungyun Kong
AU - Hitoshi Baba
AU - Akash Raj John Babu
AU - Angela Badala
AU - Joonsuk Bae
AU - Yunseul Bae
AU - Yongwook Baek
AU - Xiaozhi Bai
AU - Raphaelle Marie Bailhache
AU - Yoshini Bailung
AU - Renu Bala
AU - Alberto Baldisseri
AU - Bartosz Balis
AU - Shubham Bangalia
AU - Koushik Barai
AU - Veronika Barbasova
AU - Francesco Barile
AU - Luca Barioglio
AU - Maria Barlou
AU - Banajit Barman
AU - Gergely Gabor Barnafoldi
PY - 2026
DA - 2026/09/30
PB - HAL
DO - 10.48550/arxiv.2609.39713
UR - https://hal.science/hal-05781937v1
AB - A precise measurement of prompt and non-prompt D^*+-meson spin alignment with respect to the helicity and production axes in proton-proton (pp) collisions at √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_00 for D^*+ mesons at midrapidity (|y|<0.8). The measurement is performed in the transverse-momentum (p_T) range 3<p_T<100 GeV/c for prompt D^*+ mesons and 3<p_T<30 GeV/c for non-prompt D^*+ mesons, respectively. The measured ρ_00 values for prompt D^*+ mesons are consistent with the unpolarised expectation of 1/3 over the entire p_T range, indicating no evidence of spin alignment. In contrast, ρ_00 of non-prompt D^*+ 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 D^*+ spin alignment in heavy-ion collisions.
ER -