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1. JUNO sensitivity on proton decay p → ν K ⁺ searches*

   https://doi.org/10.1088/1674-1137/ace9c6  

   Abusleme, Angel; Adam, Thomas; Ahmad, Shakeel; Ahmed, Rizwan; Aiello, Sebastiano; Akram, Muhammad; An_安, Fengpeng 丰鹏; An_安, Qi 琪; Andronico, Giuseppe; Anfimov, Nikolay; et al (November 2023, Chinese Physics C)

   Abstract The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in themode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay viais 36.9% ± 4.9% with a background level ofevents after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure isyears, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies. 

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2. Search for two-neutrino double-beta decay of ¹³⁶ Xe to the excited state of ¹³⁶ Ba with the complete EXO-200 dataset*

   https://doi.org/10.1088/1674-1137/aceee3  

   Al_Kharusi, S; Anton, G; Badhrees, I; Barbeau, PS; Beck, D; Belov, V; Bhatta, T; Breidenbach, M; Brunner, T; Cao, GF; et al (October 2023, Chinese Physics C)

   Abstract A new search for two-neutrino double-beta (2νββ) decay of¹³⁶Xe to theexcited state of¹³⁶Ba is performed with the full EXO-200 dataset. A deep learning-based convolutional neural network is used to discriminate signal from background events. Signal detection efficiency is increased relative to previous searches by EXO-200 by more than a factor of two. With the addition of the Phase II dataset taken with an upgraded detector, the median 90% confidence level half-life sensitivity of 2νββdecay to thestate of¹³⁶Ba isyr using a total¹³⁶Xe exposure of 234.1 kg yr. No statistically significant evidence for 2νββdecay to thestate is observed, leading to a lower limit ofyr at 90% confidence level, improved by 70% relative to the current world's best constraint. 

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3. Performance and calibration of quark/gluon-jet taggers using 140 fb ⁻¹ of pp collisions at TeV with the ATLAS detector*

   https://doi.org/10.1088/1674-1137/acf701  

   Aad, G; Abbott, B; Abeling, K; Abicht, NJ; Abidi, SH; Aboulhorma, A; Abramowicz, H; Abreu, H; Abulaiti, Y; Acharya, BS; et al (February 2024, Chinese Physics C)

   Abstract The identification of jets originating from quarks and gluons, often referred to as quark/gluon tagging, plays an important role in various analyses performed at the Large Hadron Collider, as Standard Model measurements and searches for new particles decaying to quarks often rely on suppressing a large gluon-induced background. This paper describes the measurement of the efficiencies of quark/gluon taggers developed within the ATLAS Collaboration, usingTeV proton–proton collision data with an integrated luminosity of 140 fbcollected by the ATLAS experiment. Two taggers with high performances in rejecting jets from gluon over jets from quarks are studied: one tagger is based on requirements on the number of inner-detector tracks associated with the jet, and the other combines several jet substructure observables using a boosted decision tree. A method is established to determine the quark/gluon fraction in data, by using quark/gluon-enriched subsamples defined by the jet pseudorapidity. Differences in tagging efficiency between data and simulation are provided for jets with transverse momentum between 500 GeV and 2 TeV and for multiple tagger working points. 

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4. In vivo estimation of anisotropic mechanical properties of the gastrocnemius during functional loading with MR elastography

   https://doi.org/10.1088/1361-6560/acb482  

   Smith, Daniel R; Caban-Rivera, Diego A; Williams, L Tyler; Van_Houten, Elijah_E W; Bayly, Phil V; Paulsen, Keith D; McGarry, Matthew_D J; Johnson, Curtis L (February 2023, Physics in Medicine & Biology)

   Abstract Objective.In vivoimaging assessments of skeletal muscle structure and function allow for longitudinal quantification of tissue health. Magnetic resonance elastography (MRE) non-invasively quantifies tissue mechanical properties, allowing for evaluation of skeletal muscle biomechanics in response to loading, creating a better understanding of muscle functional health.Approach. In this study, we analyze the anisotropic mechanical response of calf muscles using MRE with a transversely isotropic, nonlinear inversion algorithm (TI-NLI) to investigate the role of muscle fiber stiffening under load. We estimate anisotropic material parameters including fiber shear stiffness ( ${\mu }_1$), substrate shear stiffness ( ${\mu }_2$), shear anisotropy ( $\varphi$), and tensile anisotropy ( $\zeta$) of the gastrocnemius muscle in response to both passive and active tension.Main results. In passive tension, we found a significant increase in ${\mu }_1,$ $\varphi ,$and $\zeta$with increasing muscle length. While in active tension, we observed increasing ${\mu }_2$and decreasing $\varphi$and $\zeta$during active dorsiflexion and plantarflexion—indicating less anisotropy—with greater effects when the muscles act as agonist.Significance. The study demonstrates the ability of this anisotropic MRE method to capture the multifaceted mechanical response of skeletal muscle to tissue loading from muscle lengthening and contraction. 

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5. Stellar Chromospheric Activity and Age Relation from Open Clusters in the LAMOST Survey

   https://doi.org/10.3847/1538-4357/ab4efe  

   Zhang, Jiajun; Zhao, Jingkun; Oswalt, Terry D; Fang, Xiangsong; Zhao, Gang; Liang, Xilong; Ye, Xianhao; Zhong, Jing (December 2019, The Astrophysical Journal)

   Abstract We identify member stars of more than 90 open clusters in the LAMOST survey. With the method of Fang et al., the chromospheric activity (CA) indices,for 1091 member stars in 82 open clusters andfor 1118 member stars in 83 open clusters, are calculated. The relations between the average,in each open cluster and its age are investigated in differentT_effand [Fe/H] ranges. We find that CA starts to decrease slowly from logt = 6.70 to logt = 8.50, and then decreases rapidly until logt = 9.53. The trend becomes clearer for cooler stars. The quadratic functions between logR′ and logtwith 4000 K  < T_eff < 5500 K are constructed, which can be used to roughly estimate ages of field stars with accuracy about 40% forand 60% for. 

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