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1. Measurements of the charge ratio and polarization of cosmic-ray muons with the Super-Kamiokande detector

   https://doi.org/10.1103/PhysRevD.110.082008  

   Kitagawa, H; Tada, T; Abe, K; Bronner, C; Hayato, Y; Hiraide, K; Hosokawa, K; Ieki, K; Ikeda, M; Kameda, J; et al (October 2024, Physical Review D)

   We present the results of the charge ratio ( $R$) and polarization ( $P_0^{\mu }$) measurements using decay electron events collected between September 2008 and June 2022 with the Super-Kamiokande detector. Because of its underground location and long operation, we are able to perform high-precision measurements by accumulating cosmic-ray muons. We measured the muon charge ratio to be $R=1.32\pm 0.02(\mathrm{stat}+\mathrm{syst})$at $E_{\mu }\cos {\theta }_{\text{Zenith}}={0.7}_{-0.2}^{+0.3}\mathrm{TeV}$, where $E_{\mu }$is the muon energy and ${\theta }_{\text{Zenith}}$is the zenith angle of incoming cosmic-ray muons. This result is consistent with the Honda flux model while indicating a tension with the $\pi K$model of $1.9\sigma$. We also measured the muon polarization at the production location to be $P_0^{\mu }=0.52\pm 0.02(\mathrm{stat}+\mathrm{syst})$at the muon momentum of ${0.9}_{-0.1}^{+0.6}\mathrm{TeV}/c$at the surface of the mountain; this also suggests a tension with the Honda flux model of $1.5\sigma$. This is the most precise measurement ever to experimentally determine the cosmic-ray muon polarization near $1\mathrm{TeV}/c$. These measurement results are useful to improve atmospheric neutrino simulations. Published by the American Physical Society2024 

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2. Search for resonance-enhanced $CP$ and angular asymmetries in the ${\mathrm{\Lambda }}_c^{+}\to p{\mu }^{+}{\mu }^{-}$ decay at LHCb

   https://doi.org/10.1103/PhysRevD.111.L091102  

   Aaij, R; Abdelmotteleb, A_S W; Abellan_Beteta, C; Abudinén, F; Ackernley, T; Adefisoye, A A; Adeva, B; Adinolfi, M; Adlarson, P; Agapopoulou, C; et al (May 2025, Physical Review D)

   The first measurement of the $CP$asymmetry of the decay rate ( $A_{CP}$) and the $CP$average ( $\mathrm{\Sigma }{A}_{\mathrm{FB}}$) and $CP$asymmetry ( $\mathrm{\Delta }{A}_{\mathrm{FB}}$) of the forward-backward asymmetry in the muon system of ${\mathrm{\Lambda }}_c^{+}\to p{\mu }^{+}{\mu }^{-}$decays is reported. The measurement is performed using a data sample of proton-proton collisions, recorded by the LHCb experiment from 2016 to 2018 at a center-of-mass energy of 13 TeV, which corresponds to an integrated luminosity of $5.4{\mathrm{fb}}^{-1}$. The asymmetries are measured in two regions of dimuon mass near the  $\varphi$-meson mass peak. The dimuon-mass integrated results are $A_{CP}=(-1.1\pm 4.0\pm 0.5)\%$, $\mathrm{\Sigma }{A}_{\mathrm{FB}}=(3.9\pm 4.0\pm 0.6)\%$, $\mathrm{\Delta }{A}_{\mathrm{FB}}=(3.1\pm 4.0\pm 0.4)\%$, where the first uncertainty is statistical and the second systematic. The results are consistent with the conservation of $CP$symmetry and the Standard Model expectations. © 2025 CERN, for the LHCb Collaboration2025CERN 

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3. Hadronic vacuum polarization for the muon $g-2$ from lattice QCD: Complete short and intermediate windows

   https://doi.org/10.1103/PhysRevD.111.094508  

   Bazavov, Alexei; Clarke, David A; Davies, Christine_T H; DeTar, Carleton; El-Khadra, Aida X; Gámiz, Elvira; Gottlieb, Steven; Grebe, Anthony V; Hostetler, Leon; Jay, William I; et al (May 2025, Physical Review D)

   We present complete results for the hadronic vacuum polarization (HVP) contribution to the muon anomalous magnetic moment $a_{\mu }$in the short- and intermediate-distance window regions, which account for roughly 10% and 35% of the total HVP contribution to $a_{\mu }$, respectively. In particular, we perform lattice-QCD calculations for the isospin-symmetric connected and disconnected contributions, as well as corrections due to strong-isospin breaking. For the short-distance window observables, we investigate the so-called log-enhancement effects as well as the significant oscillations associated with staggered quarks in this region. For the dominant, isospin-symmetric light-quark-connected contribution, we obtain $a_{\mu }^{ll,\mathrm{SD}}\left(\mathrm{conn}\right)=48.139\left(11{)}_{\mathrm{stat}}\right(91{)}_{\mathrm{syst}}[92{]}_{\text{total}}\times {10}^{-10}$and $a_{\mu }^{ll,\mathrm{W}}\left(\mathrm{conn}\right)=206.90\left(14{)}_{\mathrm{stat}}\right(61{)}_{\mathrm{syst}}[63{]}_{\text{total}}\times {10}^{-10}$. We use Bayesian model averaging to fully estimate the covariance matrix between the individual contributions. Our determinations of the complete window contributions are $a_{\mu }^{\mathrm{SD}}=69.05\left(1{)}_{\mathrm{stat}}\right(21{)}_{\mathrm{syst}}[21{]}_{\text{total}}\times {10}^{-10}$and $a_{\mu }^{\mathrm{W}}=236.45\left(17{)}_{\mathrm{stat}}\right(83{)}_{\mathrm{syst}}[85{]}_{\text{total}}\times {10}^{-10}$. This work is part of our ongoing effort to compute all contributions to HVP with an overall uncertainty at the few-permille level. Published by the American Physical Society2025 

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4. Measurement of Angular Coefficients of $\overline{B}\to D^{*}\ell {\overline{\nu }}_{\ell }$ : Implications for $\left|V_{cb}\right|$ and Tests of Lepton Flavor Universality

   https://doi.org/10.1103/PhysRevLett.133.131801  

   Prim, M T; Bernlochner, F; Metzner, F; Aihara, H; Asner, D M; Aushev, T; Ayad, R; Babu, V; Banerjee, Sw; Behera, P; et al (September 2024, Physical Review Letters)

   We measure the complete set of angular coefficients $J_i$for exclusive $\overline{B}\to D^{*}\ell {\overline{\nu }}_{\ell }$decays ( $\ell =e$, $\mu$). Our analysis uses the full $711{\mathrm{fb}}^{-1}$Belle dataset with hadronic tag-side reconstruction. The results allow us to extract the form factors describing the $\overline{B}\to D^{*}$transition and the Cabibbo-Kobayashi-Maskawa matrix element $\left|V_{\mathrm{cb}}\right|$. Using recent lattice QCD calculations for the hadronic form factors, we find $\left|V_{\mathrm{cb}}\right|=(40.7\pm 0.7)\times {10}^{-3}$using the Boyd-Grinstein-Lebed parametrization, compatible with determinations from inclusive semileptonic decays. We search for lepton flavor universality violation as a function of the hadronic recoil parameter $w$and investigate the differences of the electron and muon angular distributions. We find no deviation from standard model expectations. Published by the American Physical Society2024 

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5. First Measurement of ${\nu }_e$ and ${\nu }_{\mu }$ Interaction Cross Sections at the LHC with FASER’s Emulsion Detector

   https://doi.org/10.1103/PhysRevLett.133.021802  

   Abraham, Roshan Mammen; Anders, John; Antel, Claire; Ariga, Akitaka; Ariga, Tomoko; Atkinson, Jeremy; Bernlochner, Florian U; Boeckh, Tobias; Boyd, Jamie; Brenner, Lydia; et al (July 2024, Physical Review Letters)

   The first results of the study of high-energy electron neutrino ( ${\nu }_e$) and muon neutrino ( ${\nu }_{\mu }$) charged-current interactions in the $\mathrm{FASER}\nu$emulsion-tungsten detector of the FASER experiment at the LHC are presented. A 128.8 kg subset of the $\mathrm{FASER}\nu$volume was analyzed after exposure to $9.5{\mathrm{fb}}^{-1}$of $\sqrt{s}=13.6\mathrm{TeV}$ $pp$data. Four (eight) ${\nu }_e$( ${\nu }_{\mu }$) interaction candidate events are observed with a statistical significance of $5.2\sigma$( $5.7\sigma$). This is the first direct observation of ${\nu }_e$interactions at a particle collider and includes the highest-energy ${\nu }_e$and ${\nu }_{\mu }$ever detected from an artificial source. The interaction cross section per nucleon $\sigma /E_{\nu }$is measured over an energy range of 560–1740 GeV (520–1760 GeV) for ${\nu }_e$( ${\nu }_{\mu }$) to be $\left({1.2}_{-0.7}^{+0.8}\right)\times {10}^{-38}{\mathrm{cm}}^2{\mathrm{GeV}}^{-1}$[ $(0.5\pm 0.2)\times {10}^{-38}{\mathrm{cm}}^2{\mathrm{GeV}}^{-1}$], consistent with standard model predictions. These are the first measurements of neutrino interaction cross sections in those energy ranges. Published by the American Physical Society2024 

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