One of the major open questions in the neutrino sector is the issue of leptonic CP violation. Current global oscillation data show a mild preference for a large, potentially maximal value for the Dirac CP phase in the neutrino mixing matrix. In this Letter, we point out that new physics in the form of neutral-current-like nonstandard interactions with real couplings would likely yield a similar conclusion even if CP in the neutrino sector were conserved. Therefore, the claim for a discovery of leptonic CP violation will require a robust ability to test new physics scenarios.
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http://dx.doi.org/10.1103/PhysRevLett.117.031801 | DOI Listing |
Phys Rev Lett
December 2024
School of Physics, Peking University, Beijing 100871, China.
In recent years, energy correlators have emerged as a powerful tool to explore the field theoretic structure of strong interactions at particle colliders. In this Letter we initiate a novel study of the nonperturbative power corrections to the projected N-point energy correlators in the limit where the angle between the detectors is small. Using the light-ray operator product expansion as a guiding principle, we derive the power corrections in terms of two nonperturbative quantities describing the fragmentation of quarks and gluons.
View Article and Find Full Text PDFWe measure the complete set of angular coefficients J_{i} for exclusive B[over ¯]→D^{*}ℓν[over ¯]_{ℓ} decays (ℓ=e, μ). Our analysis uses the full 711 fb^{-1} Belle dataset with hadronic tag-side reconstruction. The results allow us to extract the form factors describing the B[over ¯]→D^{*} transition and the Cabibbo-Kobayashi-Maskawa matrix element |V_{cb}|.
View Article and Find Full Text PDFPhys Rev Lett
July 2024
High Energy Theory Group, Physics Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
The best way to probe CP violation in the lepton sector is with long-baseline accelerator neutrino experiments in the appearance mode: the appearance of ν_{e} in predominantly ν_{μ} beams. Here we show that it is possible to discover CP violation with disappearance experiments only, by combining JUNO for electron neutrinos and DUNE or Hyper-Kamiokande for muon neutrinos. While the maximum sensitivity to discover CP is quite modest (1.
View Article and Find Full Text PDFA search is presented for baryon number violating interactions in top quark production and decay. The analysis uses data from proton-proton collisions at a center-of-mass energy of 13 TeV, collected with the CMS detector at the LHC with an integrated luminosity of 138 fb^{-1}. Candidate events are selected by requiring two oppositely charged leptons (electrons or muons) and exactly one jet identified as originating from a bottom quark.
View Article and Find Full Text PDFPhys Rev Lett
May 2024
School of Physics and Astronomy, Sun Yat-sen University, Zhuhai 519082, People's Republic of China.
The observation of neutrinoless double-beta (0νββ) decay would offer proof of lepton number violation, demonstrating that neutrinos are Majorana particles, while also helping us understand why there is more matter than antimatter in the Universe. If the decay is driven by the exchange of the three known light neutrinos, a discovery would, in addition, link the observed decay rate to the neutrino mass scale through a theoretical quantity known as the nuclear matrix element (NME). Accurate values of the NMEs for all nuclei considered for use in 0νββ experiments are therefore crucial for designing and interpreting those experiments.
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