Wed·Sep 4, 2024Wednesday·September 4, 2024

1. 01*

   Incomplete fusion in ${}^{193}$Ir(${}^{12}$C, x)${}^{205}$Bi reaction at $E_{lab}$ $\approx$ 5-7 AMeV

   Amanjot🇮🇳 · Priyanka🇮🇳 · Subham Kumar🇮🇳 · Rupinderjeet Kaur🇮🇳 · Malika Kaushik🇮🇳 · Manoj Kumar Sharma🇮🇳 · Yashraj Jangid🇮🇳 · Pushpendra P. Singh🇮🇳

   Low-energy heavy-ion induced reactions often involve incomplete fusion, but the dependence of ICF on various entrance-channel parameters remains unclear. In this work, we measure channel-by-channel production cross-sections of different evaporation residues populated via complete and/or incomplete fusion in ${}^{12}$C+${}^{193}$Ir system at $E_{lab}$ $\approx$ 64--84 MeV ($\approx$ 5--7 AMeV) using the stacked-foil activation technique followed by offline $\gamma$-spectroscopy. Experimentally measured excitation functions have been analyzed in the framework of the statistical model code PACE4 using different values of the level-density parameter ($a$ = A/9-A/15 MeV${}^{-1}$). In the analysis of excitation functions, the $xn$ and $pxn$ channels (after correcting with their precursor contributions) have been explained fairly well with $a$ = A/13 MeV${}^{-1}$; however, almost all $\alpha$-emitting channels showed substantial enhancement over PACE4 predictions, which has been attributed to incomplete fusion. The incomplete fusion fraction ($F_{ICF}$) increases linearly with energy from 12\% to 18\% at 64 and 84 MeV, respectively. For better insights into the onset and strength of ICF, the variations of $F_{ICF}$ have been studied as a function of different entrance-channel parameters, which are found to increase with mass asymmetry, Coulomb factor, and neutron skin thickness. Further analysis of the data suggests the onset of ICF below the critical angular momentum ($\ell <{\ell }_{crit}$). Projectile breakup-driven incomplete fusion is found to suppress complete fusion by $\approx 12\%$ and $\approx 6\%$ w.r.t. the universal fusion function and the improved fusion function, respectively. These findings highlight the critical role of projectile structure at 5--7 AMeV energies, with implications for high-spin spectroscopy and reaction modeling.

   nucl-ex2 citations
2. 02*

   Inclusive photoproduction of vector quarkonium in ultra-peripheral collisions at the LHC

   Jean-Philippe Lansberg🇫🇷 · Kate Lynch🇮🇪 · Charlotte Van Hulse🇪🇸 · Ronan McNulty🇮🇪

   We explore the possibility of using ultra-peripheral proton-lead collisions at the LHC to study inclusive vector-quarkonium photoproduction, that occurs when a quasi-real photon emitted by a fully stripped lead ion breaks a proton to produce a vector quarkonium. Owing to the extremely large energies of the colliding hadrons circulating in the LHC, the range of accessible photon-nucleon centre-of-mass energies, W_gamma+p, largely exceeds what has been and will be studied at lepton-hadron colliders, HERA and the EIC. We perform a tune to HERA photoproduction data, use this tune to predict the yields of photoproduced J/psi, and estimate the corresponding transverse-momentum reach at LHC experiments. We also model the hadroproduction background and demonstrate that inclusive photoproduction can be isolated at the LHC from such background by imposing constraints on the hadronic activity in the lead-going direction at mid, forward, or far-forward rapidities depending on the capability of the detector under consideration. We find that the resulting cross sections are large enough to be measured by ALICE, ATLAS, CMS, and LHCb. We estimate the background-to-signal ratio after isolation to be of the order of 0.001 and 0.1 in the low and large transverse-momentum regions, respectively. In addition, we propose and assess the Jacquet-Blondel method to reconstruct the photon-nucleon centre-of-mass energy and the fractional energy of the quarkonium with respect to the photon.

   ↳ hep-phhep-exnucl-exnucl-thEPJC(2025)·10 citations
3. 03*

   The ITS3 detector and physics reach of the LS3 ALICE Upgrade

   Chun-Zheng Wang (for the ALICE Collaboration)🇨🇳

   During Large Hadron Collider (LHC) Long Shutdown 3 (LS3) (2026-28), the ALICE experiment is replacing its inner-most three tracking layers by a new detector, Inner Tracking System 3. It will be based on newly developed wafer-scale monolithic active pixel sensors, which are bent into truly cylindrical layers and held in place by light mechanics made from carbon foam. Unprecedented low values of material budget (per layer) and closeness to interaction point (19 mm) lead to a factor two improvement in pointing resolutions from very low $p_{\text{T}}$ (O(100MeV/$c$)), achieving, for example, 20 $\mu$m and 15 $\mu$m in the transversal and longitudinal directions, respectively, for 1 GeV/c primary charged pions. After a successful R\&D phase 2019-2023, which demonstrated the feasibility of this innovational detector, the final sensor and mechanics are being developed right now. This contribution will briefly review the conceptual design and the main R&D achievements, as well as the current activities and road to completion and installation. It concludes with a projection of the improved physics performance, in particular for heavy-flavour hadrons, as well as for thermal dielectrons, that will come into reach with this new detector installed.

   ↳ physics.ins-dethep-exnucl-exEPJ Web Conf.(2025)·0 citations
4. 04*

   Implications of first neutrino-induced nuclear recoil measurements in direct detection experiments

   D. Aristizabal Sierra🇨🇱 · N. Mishra🇺🇸 · L. Strigari🇺🇸

   PandaX-4T and XENONnT have recently reported the first measurement of nuclear recoils induced by the ${}^8$B solar neutrino flux, through the coherent elastic neutrino-nucleus scattering (CE$\nu$NS) channel. As long anticipated, this is an important milestone for dark matter searches as well as for neutrino physics. This measurement means that these detectors have reached exposures such that searches for low mass, $\lesssim 10$ GeV dark matter cannot be analyzed using the background-free paradigm going forward. It also opens a new era for these detectors to be used as neutrino observatories. In this paper we assess the sensitivity of these new measurements to new physics in the neutrino sector. We focus on neutrino non-standard interactions (NSI) and show that -- despite the still moderately low statistical significance of the signals -- these data already provide valuable information. We find that limits on NSI from PandaX-4T and XENONnT measurements are comparable to those derived using combined COHERENT CsI and LAr data, as well as those including the latest Ge measurement. Furthermore, they provide sensitivity to pure $\tau$ flavor parameters that are not accessible using stopped-pion or reactor sources. With further improvements of statistical uncertainties as well as larger exposures, forthcoming data from these experiments will provide important, novel results for CE$\nu$NS-related physics.

   ↳ hep-phastro-ph.COhep-exnucl-ex+1PRD(2025)·37 citations
5. 05*

   FPF@FCC: Neutrino, QCD, and BSM Physics Opportunities with Far-Forward Experiments at a 100 TeV Proton Collider

   Roshan Mammen Abraham🇺🇸 · Jyotismita Adhikary🇵🇱 · Jonathan L. Feng🇺🇸 · Max Fieg🇺🇸 · Felix Kling🇩🇪 · Jinmian Li🇨🇳 · Junle Pei🇨🇳 · Tanjona R. Rabemananjara🇳🇱 · Juan Rojo🇳🇱 · Sebastian Trojanowski🇵🇱

   Proton-proton collisions at energy-frontier facilities produce an intense flux of high-energy light particles, including neutrinos, in the forward direction. At the LHC, these particles are currently being studied with the far-forward experiments FASER/FASER$\nu$ and SND@LHC, while new dedicated experiments have been proposed in the context of a Forward Physics Facility (FPF) operating at the HL-LHC. Here we present a first quantitative exploration of the reach for neutrino, QCD, and BSM physics of far-forward experiments integrated within the proposed Future Circular Collider (FCC) project as part of its proton-proton collision program (FCC-hh) at $\sqrt{s}\simeq 100$ TeV. We find that $10^9$ electron/muon neutrinos and $10^7$ tau neutrinos could be detected, an increase of several orders of magnitude compared to (HL-)LHC yields. We study the impact of neutrino DIS measurements at the FPF@FCC to constrain the unpolarised and spin partonic structure of the nucleon and assess their sensitivity to nuclear dynamics down to $x\sim 10^{-9}$ with neutrinos produced in proton-lead collisions. We demonstrate that the FPF@FCC could measure the neutrino charge radius for ${\nu }_e$ and ${\nu }_{\mu }$ and reach down to five times the SM value for ${\nu }_{\tau }$. We fingerprint the BSM sensitivity of the FPF@FCC for a variety of models, including dark Higgs bosons, relaxion-type scenarios, quirks, and millicharged particles, finding that these experiments would be able to discover LLPs with masses as large as 50 GeV and couplings as small as $10^{-8}$, and quirks with masses up to 10 TeV. Our study highlights the remarkable opportunities made possible by integrating far-forward experiments into the FCC project, and it provides new motivation for the FPF at the HL-LHC as an essential precedent to optimize the forward physics experiments that will enable the FCC to achieve its full physics potential.

   ↳ hep-phhep-exnucl-exJHEP(2025)·37 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.