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Broussard, L. J. et al, & Bas i Beneito, A. (2025). Baryon number violation: from nuclear matrix elements to BSM physics. J. Phys. G, 52(8), 083001–28pp.
Abstract: Processes that violate baryon number, most notably proton decay and nn(sic) transitions, are promising probes of physics beyond the Standard Model (BSM) needed to understand the lack of antimatter in the Universe. To interpret current and forthcoming experimental limits, theory input from nuclear matrix elements to UV complete models enters. Thus, an interplay of experiment, effective field theory, lattice QCD, and BSM model building is required to develop strategies to accurately extract information from current and future data and maximize the impact and sensitivity of next-generation experiments. Here, we briefly summarize the main results and discussions from the workshop 'INT-25-91W: Baryon Number Violation: From Nuclear Matrix Elements to BSM Physics,' held at the Institute for Nuclear Theory, University of Washington, Seattle, WA, 13-17 January 2025.
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Casale, P. R., Amaro, J. E., Belocchi, V., Barbaro, M. B., De Pace, A., & Martini, M. (2025). Interference between meson exchange and one-body currents in quasielastic electron scattering. Phys. Rev. C, 112(2), 024603–29pp.
Abstract: In this work, we present a detailed analysis of the interference between meson exchange currents (MEC) and one-body currents in quasielastic electron scattering, with a focus on the sign of this interference in the transverse response for one-particle emission. We prove that the interference of both the Delta and pion-in-flight currents with the one-body current is negative, leading to a partial cancellation with the seagull current. This is mathematically demonstrated within the framework of the Fermi gas model. By comparing these interferences across various independent particle models, both relativistic and nonrelativistic, our results indicate that all studied models display the same behavior.
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Mantani, L., & Sanz, V. (2025). Probing the flavour-blind SMEFT: EFT validity and the interplay of energy scales. J. High Energy Phys., 06(6), 147–31pp.
Abstract: The Standard Model Effective Field Theory (SMEFT) offers a systematic approach to study potential deviations from the Standard Model (SM) through higher-dimensional operators that encapsulate new physics effects. In this work, we analyze flavour-blind SMEFT contributions to flavour observables and assess their interplay with high-energy measurements from LEP and LHC. We perform global fits combining LEP precision data, flavour observables from rare B-meson decays, and LHC diboson measurements, revealing how the inclusion of different datasets breaks parameter degeneracies and enhances the sensitivity to SMEFT coefficients. Our study demonstrates that low-energy flavour observables provide reliable constraints even in flavour-blind scenarios, while high-energy measurements can be subject to EFT validity concerns due to kinematic growth. We investigate the impact of renormalization group evolution (RGE) and operator mixing across energy scales, highlighting the complementary nature of low- and high-energy datasets. The results emphasize the importance of flavour observables as robust probes of new physics and underline the necessity of global fits to avoid potential biases from limited datasets. Finally, we discuss the implications of our findings for the interpretation of global SMEFT analyses based on high-energy collider data, comparing UV models that contribute to SMEFT at tree- and loop-level.
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LHCb Collaboration(Aaij, R. et al), Fernandez Casani, A., Jaimes Elles, S. J., Jashal, B. K., Libralon, S., Martinez-Vidal, F., et al. (2025). Angular analysis of B0 → K*0 e+ e- decays. J. High Energy Phys., 06(6), 140–53pp.
Abstract: An angular analysis of B0 -> K*0e+e- decays is presented using proton-proton collision data collected by the LHCb experiment at centre-of-mass energies of 7, 8 and 13 TeV, corresponding to an integrated luminosity of 9 fb-1. The analysis is performed in the region of the dilepton invariant mass squared of 1.1-6.0 GeV2/c4. In addition, a test of lepton flavour universality is performed by comparing the obtained angular observables with those measured in B0 -> K*0 mu+mu- decays. In general, the angular observables are found to be consistent with the Standard Model expectations as well as with global analyses of other b -> s & ell;+& ell;- processes, where & ell; is either a muon or an electron. No sign of lepton-flavour-violating effects is observed.
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LHCb Collaboration(Aaij, R. et al), Fernandez Casani, A., Jaimes Elles, S. J., Jashal, B. K., Libralon, S., Martinez-Vidal, F., et al. (2025). Test of Lepton Flavor Universality with Bs0 → φl+ l- Decays. Phys. Rev. Lett., 134(12), 121803–15pp.
Abstract: Lepton flavor universality in rare b -> s transitions is tested for the first time using B-s(0) meson decays. The measurements are performed using pp collision data collected by the LHCb experiment between 2011 and 2018, corresponding to a total integrated luminosity of 9 fb(-1). Branching fraction ratios between the B-s(0) -> phi e(+) e(-) and B-s(0) -> phi mu(+) mu(-) decays are measured in three regions of dilepton mass squared, q(2), with 0.1 < q(2) < 1.1, 1.1 < q(2) < 6.0, and 15 < q(2) < 19 GeV2/c(4). The results agree with the standard model expectation of lepton flavor universality.
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