Fri·Jul 19, 2024Friday·July 19, 2024

1. 01*

   Recent heavy-flavour measurements from ALICE

   Jonghan Park (for the ALICE Collaboration)🇯🇵

   Studying heavy-flavour mesons and baryons in hadronic collisions provides unique insights into the properties of heavy-quark hadronisation amid large partonic densities, where novel mechanisms beyond in-vacuum fragmentation may emerge. Examining heavy-flavour production across different collision systems and event multiplicities provides information about multi-parton interactions and the development of a strongly-interacting medium in high-multiplicity pp and p-Pb collisions. In Pb-Pb collisions, measurements of the nuclear modification factor ($R_{\mathrm{AA}}$) for charm and beauty hadrons provide a means to characterise the in-medium energy loss of heavy quarks in the quark-gluon plasma (QGP). In addition, measurements of the elliptic flow ($v_2$) for heavy quarks provide insights into their diffusion and their participation in the collective motion of the QGP. In this contribution, recent results of charm and beauty production measured with the ALICE detector are presented.

   nucl-exhep-exPoS(2025)·1 citation
2. 02*

   Multiplicity dependence of charm baryon and charm meson production in pPb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 8.16 TeV

   CMS Collaboration

   Measurements of the production yields of charm baryons (${\Lambda }_{\mathrm{c}}^{+}$) and charm mesons (D${}^0$) in proton-lead collisions at a nucleon-nucleon center-of-mass energy of 8.16 TeV are presented. The data were collected in 2016 with the CMS experiment and correspond to an integrated luminosity of 186 nb${}^{-1}$. The ${\Lambda }_{\mathrm{c}}^{+}$ baryon is reconstructed from the decay channel ${\Lambda }_{\mathrm{c}}^{+}$ $\to$ K${}_{\mathrm{S}}^0$, while the D${}^0$ meson is reconstructed via D${}^0$ $\to$ K${}^{-}$${\pi }^{+}$. The ${\Lambda }_{\mathrm{c}}^{+}$ baryon and D${}^0$ meson yields are extracted in several charged-particle multiplicity classes. No strong multiplicity dependence of the ${\Lambda }_{\mathrm{c}}^{+}$-to-D${}^0$ yield ratio is observed, unlike the observed strange baryon to strange meson yield ratio of $\Lambda /\bar{\Lambda }$ to K${}_{\mathrm{S}}^0$, which shows a strong multiplicity dependence. This observation indicates different mechanisms for the multiplicity evolution of hadronization processes for charm and strange quarks and provides new constraints to the understanding of heavy flavor production and collectivity in small collision systems.

   nucl-exhep-exPLB(2025)·1 citation
3. 03*

   Dimuon and ditau production in photon-photon collisions at next-to-leading order in QED

   Hua-Sheng Shao🇫🇷 · David d'Enterria🇨🇭

   Next-to-leading-order (NLO) quantum electrodynamics (QED) corrections to the production of muon and tau pairs in photon-photon collisions, $\gamma \gamma \to {\mu }^{+}{\mu }^{-},{\tau }^{+}{\tau }^{-}$, are calculated in the equivalent photon approximation. We mostly consider $\gamma \gamma$ processes in ultraperipheral collisions of hadrons at the LHC, but the $\gamma \gamma \to {\tau }^{+}{\tau }^{-}$ process in ${\mathrm{e}}^{+}{\mathrm{e}}^{-}$ collisions at LEP is also discussed. The NLO terms are found to modify the total fiducial cross sections by up to 5%, increasing the tails of the dilepton acoplanarity and transverse momentum distributions, and depleting by up to 15% the yields at high masses, with respect to the leading-order predictions including the very small virtuality of the colliding photons. At the LHC, the calculations obtained with the charge form factor for protons and lead ions including the NLO QED corrections improve the data--theory agreement for all measured differential distributions, and prove an indispensable ingredient for the extraction of precision quantities in photon-photon processes, such as the anomalous magnetic moment of the tau lepton.

   ↳ hep-phhep-exnucl-exnucl-thJHEP(2025)·22 citations
4. 04*

   Phase-Imaging Ion-Cyclotron-Resonance Mass Spectrometry with the Canadian Penning Trap at CARIBU

   D. Ray🇨🇦 · A. A. Valverde🇺🇸 · M. Brodeur🇺🇸 · F. Buchinger🇨🇦 · J. A. Clark🇺🇸 · B. Liu🇺🇸 · G. E. Morgan · R. Orford🇺🇸 · W. S. Porter🇺🇸 · G. Savard🇺🇸 · K. S. Sharma🇨🇦 · X. L. Yan🇨🇳

   The Canadian Penning Trap mass spectrometer (CPT) has conducted precision mass measurements of neutron-rich nuclides from the CAlifornium Rare Isotope Breeder Upgrade (CARIBU) of the Argonne Tandem Linac Accelerator System (ATLAS) facility at Argonne National Laboratory using the Phase-Imaging Ion-Cyclotron-Resonance (PIICR) technique for over half a decade. Here we discuss the CPT system, and methods to improve accuracy and precision in mass measurement using PI-ICR including some optimization techniques and recently studied systematic effects.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2025)·8 citations
5. 05*

   Imaging the Wakes of Jets with Energy-Energy-Energy Correlators

   Hannah Bossi🇺🇸 · Arjun Srinivasan Kudinoor🇺🇸 · Ian Moult🇺🇸 · Daniel Pablos🇪🇸 · Ananya Rai🇺🇸 · Krishna Rajagopal🇺🇸

   As the partons in a jet propagate through the quark-gluon plasma (QGP) produced in a heavy-ion collision, they lose energy to, kick, and are kicked by the medium. The resulting modifications to the parton shower encode information about the microscopic nature of QGP. The momentum and energy lost by the parton shower are gained by the medium and, since QGP is a strongly coupled liquid, this means that the jet excites a wake in the droplet of QGP. After freezeout, this wake becomes soft hadrons with net momentum in the jet direction meaning that reconstructed jets include hadrons originating from both the modified parton shower and its wake. This makes it challenging to find an unambiguous experimental view of the response of a droplet of QGP to a jet. Recent years have seen significant advances in the understanding of the substructure of jets using correlation functions of the energy flux operator. So far, such studies have focused primarily on the two-point correlator, which serves to identify the angular scale of the underlying dynamics. Higher-point correlators hold the promise of mapping out the dynamics themselves. We perform the first study of the shape-dependent three-point energy-energy-energy correlator in heavy-ion collisions. Using the Hybrid Model to simulate the interactions of high energy jets with QGP, we show that hadrons originating from wakes are the dominant contribution to the three-point correlator in the regime where the three points are well-separated in angle, forming a roughly equilateral triangle. This equilateral region of the correlator is far from the region populated by collinear vacuum emissions, making it a canvas on which jet wakes can be imaged. Our work is a key step towards the systematic use of energy correlators to image and unravel the dynamical response of a droplet of QGP to a passing jet, and motivates many experimental and theoretical studies.

   ↳ hep-phhep-thnucl-exnucl-thJHEP(2024)·74 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.