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Publication - Miss Srishti Bhasin

    Observation of CP Violation in Charm Decays


    , Aaij, R, Beteta, CA, Adeva, B, Adinolfi, M, Aidala, CA, Ajaltouni, Z, Akar, S, Albicocco, P, Albrecht, J, Alessio, F, Albero, AA, Alkhazov, G, Cartelle, PA, Amato, S, Amhis, Y, An, L, Anderlini, L, Andreassi, G, Andreotti, M, Archilli, F, D'Argent, P, Romeu, JA, Artamonov, A, Artuso, M, Arzymatov, K, Aslanides, E, Atzeni, M, Audurier, B, Bachmann, S, Back, JJ, Balagura, V, Baldini, W, Baranov, A, Barsuk, S, Barter, W, Bhasin, S, Buchanan, E, Chapman, MG, Dalseno, J & others 2019, ‘Observation of CP Violation in Charm Decays’. Physical Review Letters, vol 122.


    A search for charge-parity (CP) violation in D0→K-K+ and D0→π-π+ decays is reported, using pp collision data corresponding to an integrated luminosity of 5.9 fb-1 collected at a center-of-mass energy of 13 TeV with the LHCb detector. The flavor of the charm meson is inferred from the charge of the pion in D∗(2010)+→D0π+ decays or from the charge of the muon in B̄→D0μ-ν̄μX decays. The difference between the CP asymmetries in D0→K-K+ and D0→π-π+ decays is measured to be ΔACP=[-18.2±3.2(stat)±0.9(syst)]×10-4 for π-tagged and ΔACP=[-9±8(stat)±5(syst)]×10-4 for μ-tagged D0 mesons. Combining these with previous LHCb results leads to ΔACP=(-15.4±2.9)×10-4, where the uncertainty includes both statistical and systematic contributions. The measured value differs from zero by more than 5 standard deviations. This is the first observation of CP violation in the decay of charm hadrons.

    Full details in the University publications repository