Fri·Oct 17, 2025Friday·October 17, 2025

1. 01*

   Measurement of the p$-{\Sigma }^{+}$ correlation function in pp collisions at $\sqrt{\text{s}}=13$ TeV

   ALICE Collaboration

   In this letter, the first measurement of the femtoscopic correlation of protons and ${\Sigma }^{+}$ hyperons is presented and used to study the p$-{\Sigma }^{+}$ interaction. The measurement is performed with the ALICE detector in high-multiplicity triggered pp collisions at $\sqrt{s}=13$ TeV. The ${\Sigma }^{+}$ hyperons are reconstructed using a missing-mass approach in the decay channel to $\text{p}+{\pi }^0$ with ${\pi }^0\to \gamma \gamma$, while both ${\Sigma }^{+}$ and protons are identified using a machine learning approach. These techniques result in a high reconstruction efficiency and purity, which allows the measurement of the p$-{\Sigma }^{+}$ correlation function for the first time. Thanks to the high significance achieved in the p$-{\Sigma }^{+}$ correlation signal, it is possible to discriminate between the predictions of different models of the N$-\Sigma$ interaction and to accomplish a first determination of the p$-{\Sigma }^{+}$ scattering parameters.

   nucl-exhep-exPLB(2026)·4 citations
2. 02*

   Beam Energy Measurement using a Bayesian Approach with the Stacked Foil Method

   Alexander Gottstein · Lorenzo Mercolli · Eva Kasanda · Isidre Mateu · Lars Eggimann · Elnaz Zyaee · Gaia Dellepiane · Pierluigi Casolaro · Paola Scampoli🇨🇭 · Saverio Braccini

   We present a practical method to measure the energy of proton beams at a medical cyclotron using the stacked foil technique in combination with a Bayesian inference method. By measuring the ${}^{48}$V activity induced in a stack of irradiated titanium foils, the proton energy can be inferred without relying on direct current or charge measurements, making the method suitable even for low-vacuum environments or air-exposed setups. This technique is further extended to configurations where the beam energy is degraded to levels around 8 MeV. A Bayesian fit of the measured activity profile allows not only for a robust energy estimation but also for a consistent treatment of uncertainties and nuisance parameters. Monte Carlo simulations are employed to validate the underlying assumptions, including the impact of energy dispersion or cross-section uncertainties. Our results demonstrate that this method provides accurate beam energy measurements across several typical experimental setups used at the Bern Medical Cyclotron. Additionally, we evaluate the sensitivity of the method to the choice of nuclear cross-section data and assess how the number of foils in the stack affects the uncertainty in the inferred beam energy.

   ↳ physics.acc-phhep-exnucl-exphysics.ins-detNucl.Instrum.Meth.A(2026)·1 citation

* 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.