Measurement of the CKM angle γ and $$ {B}_s^0\hbox{-} {\overline{B}}_s^0 $$ mixing frequency with $$ {B}_s^0\to {D}_s^{\mp }{h}^{\pm }{\pi}^{\pm }{\pi}^{\mp } $$ decays



Aaij, R, Abellán Beteta, C, Ackernley, T, Adeva, B, Adinolfi, M, Afsharnia, H, Aidala, CA, Aiola, S, Ajaltouni, Z, Akar, S
et al (show 963 more authors) (2021) Measurement of the CKM angle γ and $$ {B}_s^0\hbox{-} {\overline{B}}_s^0 $$ mixing frequency with $$ {B}_s^0\to {D}_s^{\mp }{h}^{\pm }{\pi}^{\pm }{\pi}^{\mp } $$ decays. Journal of High Energy Physics, 2021 (3).

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Abstract

<jats:title>A<jats:sc>bstract</jats:sc></jats:title><jats:p>The CKM angle<jats:italic>γ</jats:italic>is measured for the first time from mixing-induced<jats:italic>CP</jats:italic>violation between<jats:inline-formula><jats:alternatives><jats:tex-math>$$ {B}_s^0\to {D}_s^{\mp }{K}^{\pm }{\pi}^{\pm }{\pi}^{\mp } $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mi>B</mml:mi><mml:mi>s</mml:mi><mml:mn>0</mml:mn></mml:msubsup><mml:mo>→</mml:mo><mml:msubsup><mml:mi>D</mml:mi><mml:mi>s</mml:mi><mml:mo>∓</mml:mo></mml:msubsup><mml:msup><mml:mi>K</mml:mi><mml:mo>±</mml:mo></mml:msup><mml:msup><mml:mi>π</mml:mi><mml:mo>±</mml:mo></mml:msup><mml:msup><mml:mi>π</mml:mi><mml:mo>∓</mml:mo></mml:msup></mml:math></jats:alternatives></jats:inline-formula>and<jats:inline-formula><jats:alternatives><jats:tex-math>$$ {\overline{B}}_s^0\to {D}_s^{\pm }{K}^{\mp }{\pi}^{\mp }{\pi}^{\pm } $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mover><mml:mi>B</mml:mi><mml:mo>¯</mml:mo></mml:mover><mml:mi>s</mml:mi><mml:mn>0</mml:mn></mml:msubsup><mml:mo>→</mml:mo><mml:msubsup><mml:mi>D</mml:mi><mml:mi>s</mml:mi><mml:mo>±</mml:mo></mml:msubsup><mml:msup><mml:mi>K</mml:mi><mml:mo>∓</mml:mo></mml:msup><mml:msup><mml:mi>π</mml:mi><mml:mo>∓</mml:mo></mml:msup><mml:msup><mml:mi>π</mml:mi><mml:mo>±</mml:mo></mml:msup></mml:math></jats:alternatives></jats:inline-formula>decays reconstructed in proton-proton collision data corresponding to an integrated luminosity of 9 fb<jats:sup><jats:italic>−</jats:italic>1</jats:sup>recorded with the LHCb detector. A time-dependent amplitude analysis is performed to extract the<jats:italic>CP</jats:italic>-violating weak phase<jats:italic>γ</jats:italic>− 2<jats:italic>β</jats:italic><jats:sub><jats:italic>s</jats:italic></jats:sub>and, subsequently,<jats:italic>γ</jats:italic>by taking the<jats:inline-formula><jats:alternatives><jats:tex-math>$$ {B}_s^0\hbox{-} {\overline{B}}_s^0 $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mi>B</mml:mi><mml:mi>s</mml:mi><mml:mn>0</mml:mn></mml:msubsup><mml:mo>‐</mml:mo><mml:msubsup><mml:mover><mml:mi>B</mml:mi><mml:mo>¯</mml:mo></mml:mover><mml:mi>s</mml:mi><mml:mn>0</mml:mn></mml:msubsup></mml:math></jats:alternatives></jats:inline-formula>mixing phase<jats:italic>β</jats:italic><jats:sub><jats:italic>s</jats:italic></jats:sub>as an external input. The measurement yields<jats:italic>γ</jats:italic>= (44 ± 12)° modulo 180°, where statistical and systematic uncertainties are combined. An alternative model-independent measurement, integrating over the five-dimensional phase space of the decay, yields<jats:inline-formula><jats:alternatives><jats:tex-math>$$ \gamma =\left({44}_{-13}^{+20}\right){}^{\circ} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>γ</mml:mi><mml:mo>=</mml:mo><mml:mfenced><mml:msubsup><mml:mn>44</mml:mn><mml:mrow><mml:mo>−</mml:mo><mml:mn>13</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>20</mml:mn></mml:mrow></mml:msubsup></mml:mfenced><mml:mo>°</mml:mo></mml:math></jats:alternatives></jats:inline-formula>modulo 180°. Moreover, the<jats:inline-formula><jats:alternatives><jats:tex-math>$$ {B}_s^0\hbox{-} {\overline{B}}_s^0 $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mi>B</mml:mi><mml:mi>s</mml:mi><mml:mn>0</mml:mn></mml:msubsup><mml:mo>‐</mml:mo><mml:msubsup><mml:mover><mml:mi>B</mml:mi><mml:mo>¯</mml:mo></mml:mover><mml:mi>s</mml:mi><mml:mn>0</mml:mn></mml:msubsup></mml:math></jats:alternatives></jats:inline-formula>oscillation frequency is measured from the flavour-specific control channel<jats:inline-formula><jats:alternatives><jats:tex-math>$$ {B}_s^0\to {D}_s^{-}{\pi}^{+}{\pi}^{+}{\pi}^{-} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mi>B</mml:mi><mml:mi>s</mml:mi><mml:mn>0</mml:mn></mml:msubsup><mml:mo>→</mml:mo><mml:msubsup><mml:mi>D</mml:mi><mml:mi>s</mml:mi><mml:mo>−</mml:mo></mml:msubsup><mml:msup><mml:mi>π</mml:mi><mml:mo>+</mml:mo></mml:msup><mml:msup><mml:mi>π</mml:mi><mml:mo>+</mml:mo></mml:msup><mml:msup><mml:mi>π</mml:mi><mml:mo>−</mml:mo></mml:msup></mml:math></jats:alternatives></jats:inline-formula>to be ∆<jats:italic>m</jats:italic><jats:sub><jats:italic>s</jats:italic></jats:sub>= (17<jats:italic>.</jats:italic>757 ± 0<jats:italic>.</jats:italic>007(stat) ± 0<jats:italic>.</jats:italic>008(syst)) ps<jats:sup><jats:italic>−</jats:italic>1</jats:sup>, consistent with and more precise than the current world-average value.</jats:p>

Item Type: Article
Divisions: Faculty of Science and Engineering > School of Physical Sciences
Depositing User: Symplectic Admin
Date Deposited: 21 Apr 2021 10:27
Last Modified: 18 Jan 2023 22:51
DOI: 10.1007/jhep03(2021)137
Open Access URL: https://link.springer.com/content/pdf/10.1007/JHEP...
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URI: https://livrepository.liverpool.ac.uk/id/eprint/3120044