We present updated measurements of CP-violating asymmetries in the decays B0-->D*(+/-)D(-/+) and B0-->D+D- using (383+/-4) x 10(6)B(B) pairs collected by the BABAR detector at the SLAC PEP-II B factory. We determine the time-integrated CP asymmetry A(D*(+/-)D(-/+))=0.12+/-0.06+/-0.02, and the time-dependent asymmetry parameters to be C(D*+D-)=0.18+/-0.15+/-0.04, S(D*+D-)=-0.79+/-0.21+/-0.06, C(D*-D+)=0.23+/-0.15+/-0.04, S(D*-D+)=-0.44+/-0.22+/-0.06, C(D+D-)=0.11+/-0.22+/-0.07, and S(D+D-)=-0.54+/-0.34+/-0.06, where the first uncertainty is statistical and the second is systematic.
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http://dx.doi.org/10.1103/PhysRevLett.99.071801 | DOI Listing |
Phys Rev Lett
February 2024
Department of Physics and Astronomy, University of Manchester, Manchester, United Kingdom.
The decay-time-dependent CP asymmetry in B_{s}^{0}→J/ψ(→μ^{+}μ^{-})K^{+}K^{-} decays is measured using proton-proton collision data, corresponding to an integrated luminosity of 6 fb^{-1}, collected with the LHCb detector at a center-of-mass energy of 13 TeV. Using a sample of approximately 349 000 B_{s}^{0} signal decays with an invariant K^{+}K^{-} mass in the vicinity of the ϕ(1020) resonance, the CP-violating phase ϕ_{s} is measured, along with the difference in decay widths of the light and heavy mass eigenstates of the B_{s}^{0}-B[over ¯]_{s}^{0} system, ΔΓ_{s}, and the difference of the average B_{s}^{0} and B^{0} meson decay widths, Γ_{s}-Γ_{d}. The values obtained are ϕ_{s}=-0.
View Article and Find Full Text PDFPhys Rev Lett
December 2023
Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA.
Electroweak dipole operators in the standard-model-effective-field theory (SMEFT) are important indirect probes of quantum effects of new physics beyond the standard model (SM), yet they remain poorly constrained by current experimental analyses for lack of interference with the SM amplitudes in constructing cross section observables. In this Letter, we point out that dipole operators flip fermion helicities and so are ideally studied through single transverse spin asymmetries. We illustrate this at a future electron-positron collider with transversely polarized beams, where such an effect exhibits as azimuthal cosϕ and sinϕ distributions which originate from the interference of the electron dipole operators with the SM and are linearly dependent on their Wilson coefficients.
View Article and Find Full Text PDFPhilos Trans A Math Phys Eng Sci
May 2022
Physics Department, Theoretical Particle Physics and Cosmology Group, King's College London, Strand, London WC2R 2LS, UK.
In a modest attempt to present potentially new paradigms in cosmology, including its inflationary epoch, and initiate discussions, I review in this article some novel, string-inspired cosmological models, which entail a purely geometrical origin of the dark sector of the Universe but also of its observed matter-antimatter asymmetry. The models contain gravitational (string-model independent, Kalb-Ramond (KR)) axion fields coupled to primordial gravitational anomalies via CP-violating interactions. The anomaly terms are four-space-time-dimensional remnants of the Green-Schwarz counterterms appearing in the definition of the field strength of the spin-one antisymmetric tensor field of the (bosonic) massless gravitational string multiplet, which also plays the role of a totally antisymmetric component of torsion.
View Article and Find Full Text PDFPhys Rev Lett
February 2022
Institute for Fundamental Science, University of Oregon, Eugene, Oregon 94703, USA.
One of the outstanding problems in physics is to explain the baryon-antibaryon asymmetry observed in nature. According to the well-known Sakharov criterion for explaining the observed asymmetry, it is essential that CP violation exist. Even though CP violation has been observed in meson decays and is an integral part of the standard model (SM), measurements in meson decays indicate that CP violation in the SM is insufficient to explain the observed baryon-antibaryon asymmetry.
View Article and Find Full Text PDFEur Phys J A Hadron Nucl
April 2021
Facility for Rare Isotope Beams, Physics Department, Michigan State University, East Lansing, MI 48824 USA.
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