China

Xuewei Liu

Wei Dou

Japan

Benda Xu

Hanwen Wang

Guofu Cao

Erratum to: First-principle event reconstruction by time-charge readouts for TAO

The Taishan Antineutrino Observatory (TAO) is a liquid-scintillator satellite experiment of the Jiangmen Underground Neutrino Observatory (JUNO) to measure the reference reactor neutrino spectrum with unprecedented energy resolution. We use inhomogeneous Poisson process and Tweedie generalized linear model (GLM) to characterize the detector response and the charge distribution of a SiPM. We develop a pure probabilistic model for time and charge of SiPMs from first principles to reconstruct point-like events in the TAO central detector. Thanks to our precise model and the high photo-coverage and quantum efficiency of the SiPM tiles at TAO, we achieve vertex position resolution better than $$20\,\hbox {mm}$$ , energy resolution of about $$2\%$$ at $$1\,\hbox {MeV}$$ and $$<0.5\%$$ non-uniformity, marking the world’s best performance of liquid scintillator detectors. With such resolution, we perceive $$\hbox {MeV}$$ events to exhibit track effects. It opens up an exciting possibility of computed tracking calorimeter for unsegmented liquid scintillator detector like TAO. Our methodology is applicable to other experiments that utilize PMTs for time and charge readouts.

First-principle event reconstruction by time-charge readouts for TAO

In this paper, we investigate the optical properties of a charged black hole with scalar hair (CSH) within the context of four-dimensional Einstein–Maxwell–Dilaton gravity. To achieve this, we consider three distinct toy models of thin accretion disks. The presence of dilaton coupling allows us to express both the solutions of CSH and the Reissner–Nordström (RN) black hole in terms of their mass (M) and charge (Q). Our findings reveal differences in the effective potentials  $$V_{eff}$$  <math> <msub> <mi>V</mi> <mrow> <mi>eff</mi> </mrow> </msub> </math>  , photon sphere radii  $$r_{ph}$$  <math> <msub> <mi>r</mi> <mrow> <mi>ph</mi> </mrow> </msub> </math>  , and innermost stable circular orbit  $$r_{isco}$$  <math> <msub> <mi>r</mi> <mrow> <mi>isco</mi> </mrow> </msub> </math>   between the CSH and RN black hole cases, which become increasingly pronounced as the charge parameter Q increases. However, no noticeable distinctions are observed concerning the critical impact parameter  $$b_{ph}$$  <math> <msub> <mi>b</mi> <mrow> <mi>ph</mi> </mrow> </msub> </math>  . When the ratio of the photon ring band and the lensed ring band exceeds 0.1, it may suggest the presence of a charged black hole with scalar hair. Furthermore, our results underscore the significant influence of the charge parameter Q on the brightness distributions of the direct, lensed ring, and photon ring for three standard emission functions. These findings emphasize the potential for distinguishing between CSH and RN black holes through an analysis of direct intensity and peak brightness in specific accretion disk models.

Tao-Tao Sui

Zi-Liang Wang

Wen-Di Guo

The effect of scalar hair on the charged black hole with the images from accretions disk

In this paper, we investigate the shadows and rings of the charged Horndeski black hole illuminated by accretion flow that is both geometrically and optically thin. We consider two types of accretion models: spherical and thin-disk accretion flow. We find that in both types of models, the size of the charged Horndeski black hole shadow decreases with the increase of the charge, and it decreases more slowly for the Reissner–Nordström (RN) black hole. In the spherical accretion flow model, we find that the increase of the charge of Horndeski black hole brightens the light ring around it, and it brightens more significantly in comparison with RN black hole. Due to the Doppler effect, the charged Horndeski black holes with accretion flow of radial motion have darker shadows than those with the static accretion flow, but the size of the shadow is not affected by accretion flow motion. In the thin disk-shaped accretion flow model, we find that the brightness of the light ring around the charged Horndeski black hole is dominated by the direct emission from the accretion flow, and the contribution from lensed rings is relatively small, and that from the photon rings is negligible. We also find that the ring brightness decreases as the charge of Horndeski black hole increases, and the decrease is more significant than that in the RN black hole case. Moreover, the radiation position of the accretion flow can affect the shadow size and the ring brightness of the charged Horndeski black hole.

Xiao-Jun Gao

Xiao-Xiong Zeng

Yu-Sen An

Ya-Peng Hu

Investigating shadow images and rings of the charged Horndeski black hole illuminated by various thin accretions

In this paper, we study the influence of the parameters for the accelerating Kerr-Newman black hole on the shadows and the constraints, extensively. We find that the rotating parameter a, the charge parameter e, and the inclination angle <math><msub><mrow><mi>θ</mi></mrow><mrow><mn>0</mn></mrow></msub></math> affect the shadow qualitatively similar to that of Kerr-Newman black holes. The result shows that the size of the shadow will scale down with the accelerating factor A. Besides, the factor A also can affect the best viewing angles, which make the observations maximum deviate from <math><msub><mrow><mi>θ</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>=</mo><mfrac><mrow><mi>π</mi></mrow><mrow><mn>2</mn></mrow></mfrac></math>, and the degree of the deviations are less than 1%. Then, we assume the M87* as an accelerating Kerr-Newman black hole with the mass <math><mi>M</mi><mo>=</mo><mn>6.5</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mn>9</mn></mrow></msup><msub><mrow><mi>M</mi></mrow><mrow><mo>⊙</mo></mrow></msub></math> and the distance <math><msub><mrow><mi>r</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>=</mo><mn>16.8</mn><mi>M</mi><mi>p</mi><mi>c</mi></math>. Combining the EHT observations, we find that neither the observations, circularity deviation ΔC or axial ratio <math><msub><mrow><mi>D</mi></mrow><mrow><mi>x</mi></mrow></msub></math> can distinguish the accelerating black hole or not. However, the characteristic areal-radius of the shadow curve <math><msub><mrow><mi>R</mi></mrow><mrow><mi>a</mi></mrow></msub></math> can give corresponding constraints on the parameters of the accelerating Kerr-Newman black hole. The result shows that the bigger accelerating factor A is, the stronger constraints on the rotating parameter a and charged parameter e. The maximum range of the accelerating factor is <math><mi>A</mi><msub><mrow><mi>r</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>≤</mo><mn>0.558</mn></math> for a accelerating Schwarzschild case with <math><mo>(</mo><mi>a</mi><mo>/</mo><mi>M</mi><mo>=</mo><mi>e</mi><mo>/</mo><mi>M</mi><mo>=</mo><mn>0</mn><mo>)</mo></math>, and for an extremely slow accelerating case <math><mo>(</mo><mi>A</mi><msub><mrow><mi>r</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>≤</mo><mn>0.01</mn><mo>)</mo></math>, the ranges of rotating parameter a and charged parameter e are <math><mi>a</mi><mo>/</mo><mi>M</mi><mo>∈</mo><mo>(</mo><mn>0</mn><mo>,</mo><mn>1</mn><mo>)</mo></math> and <math><mi>e</mi><mo>/</mo><mi>M</mi><mo>∈</mo><mo>(</mo><mn>0</mn><mo>,</mo><mn>0.9</mn><mo>)</mo></math>.

Qi-Ming Fu

The shadows of accelerating Kerr-Newman black hole and constraints from M87*

In extra dimensional theories, the four-dimensional field theory is reduced from a fundamental field theory in the bulk spacetime by integrating the extra dimensional part. In this paper we investigate the effective action of a self-interacting scalar field on a brane in the five-dimensional thick braneworld scenario. We consider two typical thick brane solutions and obtain the Pöschl–Teller and harmonic potentials of the Kaluza–Klein (KK) modes, respectively. The analytical mass spectra and wave functions along extra dimension of the KK modes are obtained. Further, the effective coupling constant between different KK particles, cross section, and decay rate for some processes of the KK particles are related to the fundamental coupling in five dimensions and the new physics energy scale. Some interesting properties of these interactions are found with these calculations. The KK particles with higher mode have longer lifetime, and they almost do not interact with ordinary matter on the brane if their mode numbers are large enough. Thus, these KK particles with higher modes might be a candidate of dark matter.

Cheng-Chen Li

Zheng-Quan Cui

Yu-Xiao Liu

Effective action of a self-interacting scalar field on brane

The Taishan Antineutrino Observatory (TAO or JUNO-TAO) is a satellite experiment of the Jiangmen Underground Neutrino Observatory (JUNO). Located near a reactor of the Taishan Nuclear Power Plant, TAO will measure the reactor antineutrino energy spectrum with an unprecedented energy resolution of  $$&lt;2\%$$  <math> <mrow> <mo>&lt;</mo> <mn>2</mn> <mo>%</mo> </mrow> </math>   at 1 MeV. Energy calibration is critical to achieve such a high energy resolution. Using the Automated Calibration Unit (ACU) and the Cable Loop System (CLS), multiple radioactive sources are deployed to various positions in the TAO detector for energy calibration. The residual non-uniformity can be controlled within 0.2%. The energy resolution degradation and energy bias caused by the residual non-uniformity can be controlled within 0.05% and 0.3%, respectively. The uncertainty of the non-linear energy response can be controlled within 0.6% with the radioactive sources of various energies, and could be further improved with cosmogenic  $$^{12}{\textrm{B}}$$  <math> <mrow> <msup> <mrow></mrow> <mn>12</mn> </msup> <mtext>B</mtext> </mrow> </math>   which is produced by the interaction of cosmic muon in the liquid scintillator. The stability of other detector parameters, e.g., the gain of each Silicon Photo-multiplier, will be monitored with an ultraviolet LED calibration system.

Hangkun Xu

Chile

Angel Abusleme

JINR

Nikolay Anfimov

France

Stéphane Callier

Agustin Campeny

Jun Cao

Cedric Cerna

Yu Chen

Russia

Alexander Chepurnov

Yayun Ding

Frederic Druillole

Italy

Andrea Fabbri

Zhengyong Fei

Maxim Gromov

Miao He

Wei He

Yuanqiang He

Joseph Hor

Shaojing Hou

Jianrun Hu

Jun Hu

Cédric Huss

Xiaolu Ji

Tao Jiang

Xiaoshan Jiang

Cécile Jolliet

Daozheng Li

Min Li

Ruhui Li

Yichen Li

Caimei Liu

Mengchao Liu

Yunzhe Liu

Claudio Lombardo

Selma Lorenzo

Peizhi Lu

Guang Luo

Stefano Mari

Xiaoyan Ma

Paolo Montini

Juan Ochoa-Ricoux

Yatian Pei

Frédéric Perrot

Fabrizio Petrucci

Xiaohui Qian

Abdel Rebii

Czechia

Bedr̆ich Roskovec

Arsenij Rybnikov

Germany

Hans Steiger

Xilei Sun

Pablo Walker

Derun Wang

Meifen Wang

Wei Wang

Zhimin Wang

Diru Wu

Xiang Xiao

Yuguang Xie

Zhangquan Xie

Wenqi Yan

Huan Yang

Haifeng Yao

Mei Ye

Chengzhuo Yuan

Kirill Zamogilnyi

Liang Zhan

Jie Zhang

Shuihan Zhang

Rong Zhao

Calibration strategy of the JUNO-TAO experiment

We study the sensitivity of JUNO and TAO to the oscillations induced by two well-motivated scenarios beyond the standard model: large extra dimensions (LEDs) and light sterile neutrinos in the context of <math><mrow><mn>3</mn><mo>+</mo><mn>1</mn></mrow></math> neutrino mixing. We find that <math><mrow><mi>JUNO</mi><mo>+</mo><mi>TAO</mi></mrow></math> can set competitive bounds on the parameter space of each scenario. In particular, we find that <math><mrow><mi>JUNO</mi><mo>+</mo><mi>TAO</mi></mrow></math> can be competitive with MINOS, DUNE, or KATRIN in the context of LED. If LEDs are present in nature, we show that the parameters could be measured with a similar precision as the standard oscillation parameters. We also show that <math><mrow><mi>JUNO</mi><mo>+</mo><mi>TAO</mi></mrow></math> can test nearly all of the parameter space preferred by gallium experiments in the context of <math><mrow><mn>3</mn><mo>+</mo><mn>1</mn></mrow></math> mixing. Finally, we discuss the possibility to distinguish the two scenarios from each other.

Colombia

Brazil

V. S. Basto-Gonzalez

D. V. Forero

C. Giunti

A. A. Quiroga

C. A. Ternes

Short-baseline oscillation scenarios at JUNO and TAO

This work presents a sensitivity study of a reactor liquid scintillator detector to three kinds of dark bosons with masses below 1 MeV, such as dark photons, axion-like particles, and light scalar bosons. The JUNO-TAO detector with Taishan nuclear reactor is taken as a reference. With a proposed 180 days of data taking, the best sensitivity result at the level of <math><mrow><mo>∼</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>5</mn></mrow></msup></mrow></math> 95% C.L. is achieved for dark photons with an optimized signal to background ratio for the electron coupling constant <math><mrow><msub><mrow><mi>g</mi></mrow><mrow><mi>X</mi></mrow></msub></mrow></math> through inverse Compton-like scattering. Similar calculations are completed for axion-like particles and scalar bosons. The background systematic uncertainty presents as the main limiting factor for the further sensitivity improvement. Several remarks are made to the controversial analysis for the NEOS experiment. Additionally the differential and the inverse differential cross sections have been derived for all three boson types and their interactions with electrons in liquid scintillator.

Mikhail Smirnov

United States

Guang Yang

Jiajun Liao

Zhuojun Hu

Jiajie Ling

Light dark bosons in the JUNO-TAO neutrino detector

In this paper, thick branes generated by the mimetic scalar field with Lagrange multiplier formulation are investigated. We give three typical thick brane background solutions with different asymptotic behaviors and show that all the solutions are stable under tensor perturbations. The effective potentials of the tensor perturbations exhibit as volcano potential, Poöschl–Teller potential, and harmonic oscillator potential for the three background solutions, respectively. All the tensor zero modes (massless gravitons) of the three cases can be localized on the brane. We also calculate the corrections to the four-dimensional Newtonian potential. On a large scale, the corrections to the four-dimensional Newtonian potential can be ignored. While on a small scale, the correction from the volcano-like potential is more pronounced than the other two cases. Combining the specific corrections to the four-dimensional Newtonian potential of these three cases and the latest results of short-range gravity experiments, we get the constraint on the scale parameter as  $$k &gt; rsim 10^{-4}$$  <math> <mrow> <mi>k</mi> <mo>≳</mo> <msup> <mn>10</mn> <mrow> <mo>-</mo> <mn>4</mn> </mrow> </msup> </mrow> </math>  eV, and constraint on the corresponding five-dimensional fundamental scale as  $$M_* &gt; rsim 10^5$$  <math> <mrow> <msub> <mi>M</mi> <mrow> <mrow></mrow> <mo>∗</mo> </mrow> </msub> <mo>≳</mo> <msup> <mn>10</mn> <mn>5</mn> </msup> </mrow> </math>  TeV.

Yu-Peng Zhang

Bao-Min Gu

Fundamental energy scale of the thick brane in mimetic gravity