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1. $$B \to K \nu \bar{\nu}, MiniBooNE and muon $$g-2$ anomalies from a dark sector

   https://doi.org/10.1103/PhysRevD.109.L031701  

   Datta, Alakabha; Marfatia, Danny; Mukherjee, Lopamudra (February 2024, Physical Review D)

   Belle II has reported the first evidence for B+→K+νν¯ with a branching ratio 2.7σ higher than the standard model expectation. We explain this, and the MiniBooNE and muon anomalous magnetic moment anomalies in a model with a dark scalar that couples to a slightly heavier sterile Dirac neutrino and that communicates with the visible sector via a Higgs portal. We make predictions for rare kaon and other B meson decays. 

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2. Muon Discrepancy Within D‐brane String Compactifications

   https://doi.org/10.1002/prop.202100084  

   Anchordoqui, Luis A.; Antoniadis, Ignatios; Huang, Xing; Lüst, Dieter; Taylor, Tomasz R. (August 2021, Fortschritte der Physik)

   null (Ed.)

   We demonstrate that the discrepancy between the anomalous magnetic moment measured at BNL and Fermilab and the Standard Model prediction could be explained within the context of low-scale gravity and large extra-dimensions. The dominant contribution to (g − 2)µ originates in Kaluza-Klein (KK) excitations (of the lepton gauge boson) which do not mix with quarks (to lowest order) and therefore can be quite light avoiding LHC constraints. We show that the KK contribution to (g − 2)µ,is universal with the string scale entering as an effective cutoff. The KK tower provides a unequivocal distinctive signal which will be within reach of the future muon smasher. 

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3. Machine learning techniques for intermediate mass gap lepton partner searches at the large hadron collider

   https://doi.org/10.1103/PhysRevD.109.075018  

   Dutta, Bhaskar; Ghosh, Tathagata; Horne, Alyssa; Kumar, Jason; Palmer, Sean; Sandick, Pearl; Snedeker, Marcus; Stengel, Patrick; Walker, Joel W (April 2024, Physical Review D)

   We consider machine learning techniques associated with the application of a boosted decision tree (BDT) to searches at the Large Hadron Collider (LHC) for pair-produced lepton partners which decay to leptons and invisible particles. This scenario can arise in the minimal supersymmetric Standard Model (MSSM), but can be realized in many other extensions of the Standard Model (SM). We focus on the case of intermediate mass splitting ( $\sim 30\mathrm{GeV}$) between the dark matter (DM) and the scalar. For these mass splittings, the LHC has made little improvement over LEP due to large electroweak backgrounds. We find that the use of machine learning techniques can push the LHC well past discovery sensitivity for a benchmark model with a lepton partner mass of $\sim 110\mathrm{GeV}$, for an integrated luminosity of $300{\mathrm{fb}}^{-1}$, with a signal-to-background ratio of $\sim 0.3$. The LHC could exclude models with a lepton partner mass as large as $\sim 160\mathrm{GeV}$with the same luminosity. The use of machine learning techniques in searches for scalar lepton partners at the LHC could thus definitively probe the parameter space of the MSSM in which scalar muon mediated interactions between SM muons and Majorana singlet DM can both deplete the relic density through dark matter annihilation and satisfy the recently measured anomalous magnetic moment of the muon. We identify several machine learning techniques which can be useful in other LHC searches involving large and complex backgrounds. Published by the American Physical Society2024 

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4. Effective field theory interpretation of lepton magnetic and electric dipole moments

   https://doi.org/10.1007/JHEP07(2021)107  

   Aebischer, Jason; Dekens, Wouter; Jenkins, Elizabeth E.; Manohar, Aneesh V.; Sengupta, Dipan; Stoffer, Peter (July 2021, Journal of High Energy Physics)

   A bstract We perform a model-independent analysis of the magnetic and electric dipole moments of the muon and electron. We give expressions for the dipole moments in terms of operator coefficients of the low-energy effective field theory (LEFT) and the Standard Model effective field theory (SMEFT). We use one-loop renormalization group improved perturbation theory, including the one-loop matching from SMEFT onto LEFT, and one-loop lepton matrix elements of the effective-theory operators. Semileptonic four-fermion operators involving light quarks give sizable non-perturbative contributions to the dipole moments, which are included in our analysis. We find that only a very limited set of the SMEFT operators is able to generate the current deviation of the magnetic moment of the muon from its Standard Model expectation. 

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5. Progress report on computing the disconnected QCD and the QCD plus QED hadronic contributions to the muon’s anomalous magnetic moment.

   https://doi.org/10.22323/1.396.0039  

   McNeile, Craig; Bazavov, Alexei; Davies, Christine; DeTar, Carleton; El-Khadra, Aida X; Gottlieb, Steven; Hatton, Dan; Jeong, Hwancheol; Kronfeld, Andreas; Lepage, Peter; et al (May 2022, The 38th International Symposium on Lattice Field Theory (LATTICE2021))

   We report progress on calculating the contribution to the anomalous magnetic moment of the muon from the disconnected hadronic diagrams with light and strange quarks and the valence QED contribution to the connected diagrams. The lattice QCD calculations use the highly- improved staggered quark (HISQ) formulation. The gauge configurations were generated by the MILC Collaboration with four flavors of HISQ sea quarks with physical sea-quark masses. 

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