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First Evidence for Mixing-Induced $CP$ Violation in B$_s^0$ → J/ψϕ(1020) Decays in $pp$ Collisions at $\sqrt{s}$ = 13 TeV

CMS Collaboration; Hayrapetyan, A.; Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Benato, L.; Bergauer, T.; Chatterjee, S.; Damanakis, K.; Dragicevic, M.; Hussain, P. S.; Jeitler, M.; Krammer, N.; Li, A.; Liko, D.; Mikulec, I.; Schieck, J.; Schöfbeck, R.; Schwarz, D.; ... mehr

Abstract:

A novel machine-learning-based flavor-tagging algorithm combining same-side and opposite-side tagging is used to obtain the equivalent of 27 500 tagged 𝐵$^0_𝑠$ →𝐽/𝜓⁢𝜙⁡(1020) decays from 𝑝⁢𝑝 collisions at √𝑠 =13  TeV, collected by the CMS experiment and corresponding to an integrated luminosity of 96.5  fb$^{−1}$. A time- and flavor-dependent angular analysis of the 𝜇$^+$⁢𝜇$^−$⁢𝐾$^+$⁢𝐾$^−$ final state, consistent with a 𝜙⁡(1020)→𝐾$^+$⁢𝐾$^−$ decay, is used to measure parameters of the 𝐵$^0_𝑠$ −$\overline{𝐵}$$^0_𝑠$ system. The weak phase is measured to be 𝜙$_s$=−73±22⁢(stat)±10⁢(syst)  mrad, which, combined with the √𝑠=8  TeV CMS result, gives 𝜙$_s$=−75±23  mrad. This value differs from zero by 3.2 standard deviations, providing the first evidence for mixing-induced 𝐶⁢𝑃 violation in 𝐵$^0_𝑠$ →𝐽/𝜓⁢𝜙⁡(1020) decays. All measured physics parameters are found to agree with standard model predictions where available.


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Originalveröffentlichung
DOI: 10.1103/ctqx-vxrj
Zugehörige Institution(en) am KIT Institut für Astroteilchenphysik (IAP)
Institut für Experimentelle Teilchenphysik (ETP)
Institut für Prozessdatenverarbeitung und Elektronik (IPE)
Scientific Computing Center (SCC)
Publikationstyp Zeitschriftenaufsatz
Publikationsmonat/-jahr 05.2026
Sprache Englisch
Identifikator ISSN: 0031-9007, 1092-0145, 1079-7114
KITopen-ID: 1000194641
Erschienen in Physical Review Letters
Verlag American Physical Society (APS)
Band 136
Heft 18
Seiten Art.Nr: 181801
Vorab online veröffentlicht am 05.05.2026
Nachgewiesen in OpenAlex
Scopus
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