New insights from the Dark Energy Spectroscopic Instrument (DESI) 2024 baryon acoustic oscillations (BAO) data, in conjunction with cosmic microwave background (CMB) and Type Ia supernova (SN) data, suggest that dark energy may not be a cosmological constant. In this work, we investigate the cosmological implications of holographic dark energy (HDE) and interacting holographic dark energy (IHDE) models, utilizing CMB, DESI BAO, and SN data. By considering the combined DESI BAO and SN data, we determine that in the IHDE model, the parameter $$c > 1$$ and the dark-energy equation of state $\textit{w}$ does not cross $$-1$$ at the $$1\sigma $$ confidence level, whereas in the HDE model, it marginally falls below this threshold. Upon incorporating CMB data, we observe that in the HDE model, the parameter $$c < 1$$ and $\textit{w}$ crosses $$-1$$ at a level beyond $$10\sigma $$ . Conversely, for the IHDE model, the likelihood of $\textit{w}$ crossing $$-1$$ is considerably diminished, implying that the introduction of interaction within the HDE model could potentially resolve or mitigate the cosmic big rip conundrum. Furthermore, our analysis reveals that the HDE and IHDE models are statistically as viable as the $$\Lambda $$ CDM model when assessing Bayesian evidence with DESI BAO data combined with SN data. However, when CMB data are added, the HDE and IHDE models are significantly less favored than the $$\Lambda $$ CDM model. Our findings advocate for further exploration of the HDE and IHDE models using forthcoming, more precise late-universe observations.

China

Tian-Nuo Li

Yun-He Li

Guo-Hong Du

Peng-Ju Wu

Lu Feng

Jing-Fei Zhang

Xin Zhang

Revisiting holographic dark energy after DESI 2024

Many physical systems, including classical fluids, present in their phase diagram the competition between two phases that are separated by a line of first-order phase transitions which terminates at a so-called critical point. Despite several proposals, in the supercritical region beyond the critical point, whether the two phases can still be distinguished and by which criterion remain open questions. In this work, we study the thermodynamics and linear dynamics of a holographic superfluid model with nonlinear potential terms in the supercritical region. We identify the presence of a dynamical crossover, akin to the liquid-like to gas-like Frenkel transition in supercritical fluids, and we define other separation lines of thermodynamic origin based on higher order derivatives of the free energy with respect to the charge density. Our results highlight the universal dynamical and thermodynamic features of supercritical systems from nuclear matter and classical fluids to superfluid systems.

Zi-Qiang Zhao

Zhang-Yu Nie

Matteo Baggioli

Dynamical and thermodynamic crossovers in the supercritical region of a holographic superfluid model

Recently, DESI has released baryon acoustic oscillation (BAO) data, and DES has also published its 5-year supernova (SN) data. These observations, combined with cosmic microwave background (CMB) data, support a dynamically evolving dark energy at a high confidence level. When using cosmological observations to weigh neutrinos, the results will be significantly affected by the measurement of dark energy due to the degeneracy between neutrino mass and the dark-energy equation of state. Therefore, we need to understand how the dynamical evolution of dark energy in the current situation will affect the measurement of neutrino mass. In this work, we utilize these latest observations and other additional distance measurements to discuss the mutual influence between neutrinos and dark energy, then calculate the Bayes factor to compare models. We consider three neutrino mass hierarchies, namely degenerate hierarchy (DH), normal hierarchy (NH), and inverted hierarchy (IH), as well as three dark energy models including $$\Lambda {\textrm{CDM}},$$ $$w{\textrm{CDM}},$$ and $$w_0w_a {\textrm{CDM}}$$ models. We find that cosmological data combined with the prior of particle physics experiments can provide strong to decisive evidence favoring the $$w_0w_a {{\textrm{CDM}}}+\sum m_\nu $$ model with NH. In the $$w_0w_a {\textrm{CDM}}$$ model, using the CMB+DESI+DESY5 data, we obtain constraints on the total neutrino mass, $$\sum m_\nu <0.171~{\textrm{eV}},\ 0.204~{\textrm{eV}},\ 0.220~{\textrm{eV}},$$ for DH, NH, and IH, respectively. Furthermore, taking into account the neutrino hierarchy or incorporating additional distance measurements results in a more pronounced deviation from the $$\Lambda $$ CDM model for dark energy. The latter, in particular, exhibits a deviation at a confidence level that surpasses $$4\sigma .$$

Impacts of dark energy on weighing neutrinos after DESI BAO

The Jiangmen Underground Neutrino Observatory (JUNO) is a multi-purpose neutrino experiment under construction in South China. This paper presents an updated estimate of JUNO’s sensitivity to neutrino mass ordering using the reactor antineutrinos emitted from eight nuclear reactor cores in the Taishan and Yangjiang nuclear power plants. This measurement is planned by studying the fine interference pattern caused by quasi-vacuum oscillations in the oscillated antineutrino spectrum at a baseline of 52.5 km and is completely independent of the CP violating phase and neutrino mixing angle θ $_{23}$. The sensitivity is obtained through a joint analysis of JUNO and Taishan Antineutrino Observatory (TAO) detectors utilizing the best available knowledge to date about the location and overburden of the JUNO experimental site, local and global nuclear reactors, JUNO and TAO detector responses, expected event rates and spectra of signals and backgrounds, and systematic uncertainties of analysis inputs. We find that a 3σ median sensitivity to reject the wrong mass ordering hypothesis can be reached with an exposure of about 6.5 years × 26.6 GW thermal power.

Chile

Angel Abusleme

France

Thomas Adam

Pakistan

Shakeel Ahmad

Rizwan Ahmed

Italy

Sebastiano Aiello

Muhammad Akram

Abid Aleem

Fengpeng An

Qi An

Giuseppe Andronico

JINR

Nikolay Anfimov

Vito Antonelli

Tatiana Antoshkina

Thailand

Burin Asavapibhop

João Pedro Athayde Marcondes de André

Didier Auguste

Weidong Bai

Nikita Balashov

Wander Baldini

Andrea Barresi

Davide Basilico

Eric Baussan

Marco Bellato

Marco Beretta

Antonio Bergnoli

Germany

Daniel Bick

Lukas Bieger

Svetlana Biktemerova

Thilo Birkenfeld

Iwan Morton-Blake

David Blum

Simon Blyth

Anastasia Bolshakova

Mathieu Bongrand

Taiwan

Clément Bordereau

Dominique Breton

Augusto Brigatti

Riccardo Brugnera

Riccardo Bruno

Antonio Budano

Jose Busto

Anatael Cabrera

Barbara Caccianiga

Hao Cai

Xiao Cai

Yanke Cai

Zhiyan Cai

Stéphane Callier

Antonio Cammi

Agustin Campeny

Chuanya Cao

Guofu Cao

Jun Cao

Rossella Caruso

Cédric Cerna

Vanessa Cerrone

Chi Chan

Jinfan Chang

Yun Chang

Auttakit Chatrabhuti

Chao Chen

Guoming Chen

Pingping Chen

Shaomin Chen

Yixue Chen

Yu Chen

Zhangming Chen

Zhiyuan Chen

Zikang Chen

Jie Cheng

Yaping Cheng

Yu Chin Cheng

Russia

Alexander Chepurnov

Alexey Chetverikov

Davide Chiesa

Brazil

Pietro Chimenti

Yen-Ting Chin

Ziliang Chu

Artem Chukanov

Gérard Claverie

Catia Clementi

Belgium

Barbara Clerbaux

Marta Colomer Molla

Selma Conforti DiLorenzo

Alberto Coppi

Daniele Corti

Simon Csakli

Flavio Dal Corso

United States

Olivia Dalager

Jaydeep Datta

Christophe De La Taille

Zhi Deng

Ziyan Deng

Xiaoyu Ding

Xuefeng Ding

Yayun Ding

Bayu Dirgantara

Carsten Dittrich

Sergey Dmitrievsky

Czechia

Tadeas Dohnal

Potential to identify neutrino mass ordering with reactor antineutrinos at JUNO  

Both particle physics experiments and cosmological observations have been used to explore neutrino properties. Cosmological researches of neutrinos often rely on the early-universe cosmic microwave background observations or other late-universe probes, which mostly focus on large-scale structures. We introduce a distinct probe, the 21-cm forest, that differs from other probes in both time and scale. Actually, the 21-cm forest is a unique tool for studying small-scale structures in the early universe. Below the free-streaming scale, massive neutrinos suppress the matter power spectrum, influencing small-scale fluctuations in the distribution of matter. The one-dimensional (1D) power spectrum of the 21-cm forest can track these fluctuations across different scales, similar to the matter power spectrum, providing an effective method to constrain neutrino mass. Although heating effects in the early universe can also impact the 1D power spectrum of the 21-cm forest, we assess the potential of the 21-cm forest as a tool for measuring neutrino mass, given that the temperature of the intergalactic medium can be constrained using other methods within a certain range. In the ideal scenario, the 21-cm forest observation will have the ability to constrain the total neutrino mass to around 0.1 eV. With the accumulation of observational data and advancements in observational technology, the 21-cm forest holds great promise as an emerging and potent tool for measuring neutrino mass.

Yue Shao

Prospects for measuring neutrino mass with 21-cm forest

We explore the decay of bound neutrons in the JUNO liquid scintillator detector into invisible particles (e.g., $$n\rightarrow 3 \nu $$ or $$nn \rightarrow 2 \nu $$ ), which do not produce an observable signal. The invisible decay includes two decay modes: $$ n \rightarrow { inv} $$ and $$ nn \rightarrow { inv} $$ . The invisible decays of -shell neutrons in $$^{12}\textrm{C}$$ will leave a highly excited residual nucleus. Subsequently, some de-excitation modes of the excited residual nuclei can produce a time- and space-correlated triple coincidence signal in the JUNO detector. Based on a full Monte Carlo simulation informed with the latest available data, we estimate all backgrounds, including inverse beta decay events of the reactor antineutrino $${\bar{\nu }}_e$$ , natural radioactivity, cosmogenic isotopes and neutral current interactions of atmospheric neutrinos. Pulse shape discrimination and multivariate analysis techniques are employed to further suppress backgrounds. With two years of exposure, JUNO is expected to give an order of magnitude improvement compared to the current best limits. After 10 years of data taking, the JUNO expected sensitivities at a 90% confidence level are $$\tau /B( n \rightarrow { inv} ) > 5.0 \times 10^{31} \, \textrm{years}$$ and $$\tau /B( nn \rightarrow { inv} ) > 1.4 \times 10^{32} \, \textrm{years}$$ .

Kai Adamowicz

João André

Iwan Blake

Steven Calvez

Xin Chen

Yiming Chen

Zelin Chen

Yu Cheng

Po-Lin Chou

Marta Molla

Selma Lorenzo

Chenyang Cui

Flavio Corso

Christophe Taille

JUNO sensitivity to invisible decay modes of neutrons

This paper presents an energy resolution study of the JUNO experiment, incorporating the latest knowledge acquired during the detector construction phase. The determination of neutrino mass ordering in JUNO requires an exceptional energy resolution better than 3% at 1 MeV. To achieve this ambitious goal, significant efforts have been undertaken in the design and production of the key components of the JUNO detector. Various factors affecting the detection of inverse beta decay signals have an impact on the energy resolution, extending beyond the statistical fluctuations of the detected number of photons, such as the properties of the liquid scintillator, performance of photomultiplier tubes, and the energy reconstruction algorithm. To account for these effects, a full JUNO simulation and reconstruction approach is employed. This enables the modeling of all relevant effects and the evaluation of associated inputs to accurately estimate the energy resolution. The results of this study reveal an energy resolution of 2.95% at 1 MeV. Furthermore, this study assesses the contribution of major effects to the overall energy resolution budget. This analysis serves as a reference for interpreting future measurements of energy resolution during JUNO data collection. Moreover, it provides a guideline for comprehending the energy resolution characteristics of liquid scintillator-based detectors.

YuChin Cheng

Selma Conforti Di Lorenzo

Prediction of energy resolution in the JUNO experiment  

We demonstrate that Debye shielding cannot be employed to constrain the cosmological abundance of magnetic monopoles, contrary to what is stated in the previous literature. Current model-independent bounds on the monopole abundance are then revisited for unit Dirac magnetic charge. We find that the Andromeda Parker bound can be employed to set an upper limit on the monopole flux at the level of F  M  ≲ 5.3 × 10−19cm−2s−1sr−1 for a monopole mass 1013 GeV/c 2 ≲ m ≲ 1016 GeV/c 2, which is more stringent than the MACRO direct search limit by two orders of magnitude. This translates into stringent constraints on the monopole density parameter Ω M  at the level of 10−7˘10−4 depending on the mass. For larger monopole masses the scenarios in which magnetic monopoles account for all or the majority of dark matter are disfavored.

Chen Zhang

Shi-Hao Zhang

Bowen Fu

On the cosmological abundance of magnetic monopoles

An exactly solvable strongly correlated electron model with two independent parameters is constructed in the frame of the quantum inverse scattering method, which can be seen as a generalization of the Bariev model. Through the Bethe ansatz method, a set of Bethe ansatz equations is derived. In the thermodynamic limit, to study the ground state of the model, we obtain the integral equations for the density of Bethe roots. Numerical validation is done to confirm the accuracy of our analytic results.

Mingchen Zheng

Junpeng Cao

Wen-Li Yang

Yupeng Wang

Exact solution of a two-parameter extended Bariev model

The behavior of quark matter with both external electric field and chiral chemical potential is theoretically and experimentally interesting to consider. In this paper, the case of simultaneous presence of imaginary electric field and chiral chemical potential is investigated using the lattice QCD approach with  $$N_f=1+1$$  <math> <mrow> <msub> <mi>N</mi> <mi>f</mi> </msub> <mo>=</mo> <mn>1</mn> <mo>+</mo> <mn>1</mn> </mrow> </math>   dynamical staggered fermions. We find that overall both the imaginary electric field and the chiral chemical potential can exacerbate chiral symmetry breaking, which is consistent with theoretical predictions. However we also find a non-monotonic behavior of chiral condensation at specific electric field strengths and chiral chemical potentials. The behavior of Polyakov loop in the complex plane is not significantly affected by chiral chemical potential in the region of the parameters considered.

Ji-Chong Yang

Jian-Xing Chen

Study of the effects of external imaginary electric field and chiral chemical potential on quark matter