arXiv subjects

Jaroslaw Nowak

Publications and source records attributed to Jaroslaw Nowak.

5 recordsLinked to original sources

arXiv2026

LUNAR: a Monte Carlo generator for bound-nucleon decay in liquid argon

The search for nucleon decay in liquid-argon time-projection chambers requires a quantitative description of how the bound nuclear environment reshapes the decay-product kinematics. We present LUNAR, a fast, openly available Monte Carlo generator dedicated to two-body decays of protons and neutrons bound in argon-40, the target nucleus of the DUNE far detector. The parent nucleon is drawn from a selectable nuclear ground state -- ten momentum distributions ranging from mean-field Fermi gases to argon spectral functions -- and bound off the mass shell by one of three removal-energy prescriptions, including the momentum-dependent optical potential of Juszczak \textit{et al}. The two-body decay is performed off-shell and boosted to the laboratory frame, and the daughter meson is then propagated out of the nucleus by a semi-classical intranuclear cascade with an optional formation zone for the freshly produced meson. We use the generator to separate the distinct roles of Fermi motion and binding in shaping the observable meson spectrum, to quantify final-state interactions channel by channel, and to translate present Super-Kamiokande limits into expected DUNE event yields for the full set of standard decay modes. Final-state interactions leave the supersymmetry-favored $p\to K^{+}\barν$ signal essentially intact while roughly halving the pion, $η$, and antikaon rates -- an effect that dominates over the $\pm10\%$ spread induced by the choice of nuclear model. The code is released to the community as a lightweight, extensible tool for signal efficiency and systematics studies.

hep-ph↗

arXiv2026

Accelerator neutrinos as a probe of in-medium hyperon potentials

Charged-current (anti)neutrino interactions create $Λ$ and $Σ$ hyperons \emph{inside} the nucleus, making hyperon final-state interactions a terrestrial probe of the in-medium potentials that govern hyperon onset in neutron stars. In the StrangeMC simulation the trapped-$Λ$ fraction, escaping hyperon momenta, and a kaon-vetoed $Σ^+$ tag respond monotonically to $U_Λ$ and $U_Σ$ at SBND and DUNE. Marginalised over the low-density slope, a forecast gives $δU_Λ\approx6\MeV$ with systematics distinct from hypernuclear data; $U_Σ$ is limited by hyperon--nucleon cross sections.

nucl-th↗

arXiv2026

Neutrino-induced hyperon final-state interactions as constraints on the in-medium hyperon potential

Hyperon single-particle potentials $U_Y(ρ)$ control propagation in nuclei and hyperon onset in dense matter, where they soften the neutron-star equation of state and reduce the maximum mass -- the ``hyperon puzzle''. We show that charged-current accelerator (anti)neutrino interactions on $^{40}$Ar, producing $Λ$ and $Σ$ inside the nucleus, can constrain these potentials. At SBND and DUNE energies, the trapped-$Λ$ fraction and escaping-hyperon momenta vary monotonically with $U_Λ$ and $U_Σ$, with a kaon-vetoed FSI-$Σ^+$ tag adding sensitivity. Inserted in a GM1 relativistic mean-field equation of state at established hypernuclear/$Σ$-atom depths, the same potentials give $M_{\rm max} = 1.94\,M_\odot$ and $Λ_{1.4}=1034$, below the heaviest pulsars and above the GW170817 bound typical of GM1-class mean fields. A detector-level Fisher forecast yields $δU_Λ\simeq 0.3\,$MeV and $δU_Σ\simeq 3$-$4\,$MeV for fixed low-density exponent $γ$. Since hyperons are produced below saturation, $U_Λ(ρ_0)$ and $γ$ are 99.8\% anti-correlated; marginalising over $γ$ degrades the anchor to $δU_Λ\simeq 5.6\,$MeV ($1.3\,$MeV with a $\pm 0.2$ prior), while $δU_Σ$ is unchanged. For $U_Λ$, comparable systematics arise from hyperon-nucleon final-state cross sections ($-5/{+}2\,$MeV) and the exit-shift/gradient transport prescription ($-6\,$MeV). For $U_Σ$, the same $YN$ uncertainty biases the fit by $\mathcal{O}(150)\,$MeV; removing the $Σ^+$ tag does not cure this, because the $Λ$ momentum spectrum carries most $U_Σ$ information and is itself $YN$-sensitive. The low-density $U_Λ$ anchor is a robust handle, at several-MeV rather than sub-MeV precision. A joint fit with terrestrial and heavy-ion priors gives $M_{\rm max} = 2.21^{+0.04}_{-0.15}\,\,$Msun, set mainly by the external $c_Λ$ prior.

nucl-th↗

arXiv2026

In-medium hyperon potentials and the quarkyonic hyperon onset: charged $Σ$'s in $β$-equilibrium and the neutrino connection

Quarkyonic matter resolves the neutron-star hyperon puzzle statistically: neutrons fill low-momentum $d$-quark phase space, shifting the $S=-1$ threshold from $\muB=M_Y$ to $2M_Y-M_N$ and suppressing residual softening by $1/\Nc^3$ in the Fujimoto--Kojo--McLerran (FKM) mechanism. We dress FKM's IdylliQ model with in-medium potentials, constrained by hypernuclear data and neutrino-induced hyperon FSI, and find: (i) the dressed onset, $\muB^{\rm onset}=(2M_Y{-}M_N)+2U_Y-\UN$, carries $U_Y$ at weight 2, with $dn_{\rm onset}/dU_Y\simeq0.3\,\nz$ per $10\MeV$, twice the leverage. (ii) A self-consistent neutron potential enters at weight $-2$, so protection needs $\UN(n_{\rm onset})\lesssim+96\MeV$. (iii) With leptons in $β$ equilibrium, the $Σ^-$ ($dds$) onset becomes $\mue\ge258\MeV+\US-\UN$, never reached inside a $2\,\Msun$ core: $Σ^-$ switches from first hyperon to forbidden and the $Σ$ ordering inverts. (iv) The $\kY\ge\kbu$ continuation gives TOV softening below $0.05\,\Msun$ in the FKM ansatz family and below $0.025\,\Msun$ for the realistic interacting star, $4$--$8$ below hadronic models. In the family this is a ceiling; generally it is a floor, since hyperons above $\kbu$ are omitted. (v) In an interacting low-density sector calibrated to $\Mmax=2.12\,\Msun$, core strangeness is controlled by $(\UL(\nz),c_Λ)$: at $\UL(\nz)=-28\MeV$, the maximum-mass star is hyperon-free once the supra-saturation $YNN$ turn-over exceeds a few-MeV threshold $c^*_Λ$. Projected SBND+DUNE FSI precision pins $\UL(\nz)$ but leaves $c_Λ$ -- to which neutrino data are blind -- decisive: with the heavy-ion prior, $P({\rm hyperon\mbox{-}free\ core})=0.90$, versus $0.89$ from priors alone, prior-dominated rather than measured. The sharpest observable is differential: $d\Mmax/dU_Y$ is an order of magnitude smaller than in mean-field models, discriminating the two resolutions.

nucl-th↗

arXiv2021

A High Pressure Time Projection Chamber with Optical Readout

Measurements of proton-nucleus scattering and high resolution neutrino-nucleus interaction imaging are key to reduce neutrino oscillation systematic uncertainties in future experiments. A High Pressure Time Projection Chamber (HPTPC) prototype has been constructed and operated at Royal Holloway University of London and CERN as a first step in the development of a HPTPC capable of performing these measurements as part of a future long-baseline neutrino oscillation experiment such as the Deep Underground Neutrino Experiment. In this paper we describe the design and operation of the prototype HPTPC with an argon based gas mixture. We report on the successful hybrid charge and optical readout, using four CCD cameras, of signals from Am-241 sources.

physics.ins-det↗