Fri·Nov 10, 2023Friday·November 10, 2023

1. 01*

   Isoscaling in Dilute Warm Nuclear Systems

   Alex Rebillard-Soulié🇫🇷 · Rémi Bougault🇫🇷 · Helena Pais🇵🇹 · Bernard Borderie🇫🇷 · Abdelouahad Chbihi🇫🇷 · Caterina Ciampi🇫🇷 · Quentin Fable🇫🇷 · John Frankland🇫🇷 · Emmanuelle Galichet🇫🇷 · Tom Génard🇫🇷 · Diégo Gruyer🇫🇷 · Nicolas Le Neindre🇫🇷 and 5 other authors

   Heavy-ion collisions are a good tool to explore hot nuclear matter below saturation density. It has been established that if a nuclear system reaches the thermal and chemical equilibrium, this leads to scaling properties in the isotope production when comparing two systems which differ in proton fraction. This article presents a study of the isoscaling properties of an expanding gas source exploring different thermodynamic states (density, temperature, proton fraction). This experimental work highlights the existence of an isoscaling relationship for hydrogen and 3He, 4He helium isotopes which agrees with the hypothesis of thermal and chemical equilibrium. Moreover, this work reveals the limitations of isoscaling when the two systems differ slightly in total mass and temperature. Also, a discrepancy has been observed for the 6He isotope, which could be explained by finite size effects or by the specific halo nature of this cluster.

   nucl-exJ.Phys.G(2024)·4 citations
2. 02*

   Dual-phase xenon time projection chambers for rare-event searches

   Laura Baudis🇨🇭

   In the past decade, dual-phase xenon time projection chambers (Xe-TPCs) have emerged as some of the most powerful detectors in the fields of astroparticle physics and rare-event searches. Developed primarily towards the direct detection of dark matter particles, experiments presently operating deep underground have reached target masses at the multi-tonne scale, energy thresholds around 1 keV and radioactivity-induced background rates similar to those from solar neutrinos. These unique properties, together with demonstrated stable operation over several years, allow for the exploration of new territory via high-sensitivity searches for a plethora of ultra-rare interactions. These include searches for particle dark matter, for second order weak decays, and the observation of astrophysical neutrinos. We first review some properties of xenon as a radiation detection medium and the operation principles of dual-phase Xe-TPCs together with their energy calibration and resolution. We then discuss the status of currently running experiments and of proposed next-generation projects, describing some of the technological challenges. We end by looking at their sensitivity to dark matter candidates, to second order weak decays and to solar and supernova neutrinos. Experiments based on dual-phase Xe-TPCs are difficult, and, like all good experiments, they are constantly pushed to their limits. Together with many other endeavours in astroparticle physics and cosmology they will continue to push at the borders of the unknown, hopefully to reveal profound new knowledge about our cosmos.

   ↳ physics.ins-detastro-ph.IMhep-exnucl-exPhil.Trans.Roy.Soc.Lond.A(2023)·18 citations
3. 03*

   Spreading widths of giant monopole resonance in the lead region: Random matrix approach

   N.N. Arsenyev🇷🇺 · A.P. Severyukhin🇷🇺 · R.G. Nazmitdinov

   The microscopic calculation of the decay width of giant monopole resonance (GMR) anticipates the mixing of one-phonon states with configurations of increasing complexity. To this aim we develop the effective approach for description of monopole excited states that are obtained in the quasiparticle random phase approximation (QRPA), with regard of the coupling between one- and two-phonon states. Based on the QRPA one-phonon states, we generate the coupling and two-phonon states by means of the Gaussian orthogonal ensemble (GOE) distribution. Within our approach the spreading width of the GMRs in ${}^{204,206,208}$Pb are described by means of a random matrix approach on two energy scales. It is demonstrated that the main contribution into the decay of the GMR is determined by a small number of two-phonon states strongly coupled to low-energy surface vibrations. While a vast majority of the coupling matrix elements (that are small in value and following the GOE distribution) are responsible for the fine structure of the GMR spreading width. A remarkable agreement between the results of the full microscopic calculations (based on QRPA phonons coupled by means of the microscopic coupling matrix elements with calculated two-phonon states) with those of the developed approach confirms the vitality of the proposed ideas.

   ↳ nucl-thnucl-exJETP Lett.(2023)·2 citations
4. 04*

   CGC and saturation approach: Impact-parameter dependent model of perturbative QCD and combined HERA data

   Michael Roa🇨🇱 · José Garrido🇨🇱 · Miguel Guevara🇨🇱

   In this paper we confront the CGC/saturation approach of Ref.~\cite{CLMS} with the experimental combined HERA data and obtain its parameters. The model includes two features that are in accordance with our theoretical knowledge of deep inelastic scattering. These consist of: \textit{i}) the use of analytical solution for the non-linear Balitsky-Kovchegov (BK) evolution equation and \textit{ii}) the exponential behavior of the saturation momentum on the impact parameter $b$-dependence, characterized by $Q_s$ $\propto \exp (-mb)$ which reproduces the correct behavior of the scattering amplitude at large $b$ in accord with Froissart theorem. The model results are then compared to data at small-$x$ for the structure-function of the proton $F_2$, the longitudinal structure function $F_L$, the charm structure function $F_2^{c\bar{c}}$, the exclusive vector meson ($J/\psi ,\varphi ,\rho$) production and Deeply Virtual Compton Scattering (DVCS). We obtain a good agreement for the processes in a wide kinematic range of $Q^2$ at small-$x$. Our results provide a strong guide for finding an approach, based on Color Glass Condensate/saturation effective theory for high energy QCD, to make reliable predictions from first principles and for forthcoming experiments like the Electron-Ion Collider and the LHeC.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2024)·5 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.