Abstract
We report the measurements of the CP -violating parameters in B 0 s → D ∓ s K± decays observed in pp collisions, using a data set corresponding to an integrated luminosity of 3.0 fb−1 recorded with the LHCb detector. We measure Cf = 0.73 ± 0.14 ± 0.05, A ΔΓ f = 0.39 ± 0.28 ± 0.15, \( {A}_{\overline{f}}^{\varDelta \varGamma }=0.31\pm 0.28\pm 0.15 \), Sf = −0.52 ± 0.20 ± 0.07, \( {S}_{\overline{f}}=-0.49\pm 0.20\pm 0.07 \), where the uncertainties are statistical and systematic, respectively. These parameters are used together with the world-average value of the B 0 s mixing phase, −2βs, to obtain a measurement of the CKM angle γ from B 0 s → D ∓ s K± decays, yielding γ = (128 + 17− 22 )° modulo 180°, where the uncertainty contains both statistical and systematic contributions. This corresponds to 3.8 σ evidence for CP violation in the interference between decay and decay after mixing.
![](http://media.springernature.com/lw685/springer-static/image/art%3A10.1007%2FJHEP03%282018%29059/MediaObjects/13130_2018_7771_Figa_HTML.png)
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
N. Cabibbo, Unitary symmetry and leptonic decays, Phys. Rev. Lett. 10 (1963) 531 [INSPIRE].
M. Kobayashi and T. Maskawa, CP violation in the renormalizable theory of weak interaction, Prog. Theor. Phys. 49 (1973) 652 [INSPIRE].
C. Jarlskog, Commutator of the quark mass matrices in the standard electroweak model and a measure of maximal CP nonconservation, Phys. Rev. Lett. 55 (1985) 1039 [INSPIRE].
R. Huerta and R. Pérez-Marcial, Comment on “commutator of the quark mass matrices in the standard electroweak model and a measure of maximal CP nonconservation”, Phys. Rev. Lett. 58 (1987) 1698.
C. Jarlskog, Jarlskog responds, Phys. Rev. Lett. 57 (1986) 2875 [INSPIRE].
LHCb collaboration, Measurement of the CKM angle γ from a combination of LHCb results, JHEP 12 (2016) 087 [arXiv:1611.03076] [INSPIRE].
I. Dunietz and R.G. Sachs, Asymmetry between inclusive charmed and anticharmed modes in B 0 , \( {\overline{B}}^0 \) decay as a measure of CP violation, Phys. Rev. D 37 (1988) 3186 [Erratum ibid. D 39 (1989) 3515] [INSPIRE].
R. Aleksan, I. Dunietz and B. Kayser, Determining the CP-violating phase γ, Z. Phys. C 54 (1992) 653 [INSPIRE].
R. Fleischer, New strategies to obtain insights into CP-violation through B (s) → D ±( s) K ∓ , D ∗ ±( s) K ∓ ,. . . and B (d) → D ± π ∓ , D ∗ ± π ∓ ,. . . decays, Nucl. Phys. B 671 (2003) 459 [hep-ph/0304027] [INSPIRE].
K. De Bruyn, R. Fleischer, R. Knegjens, M. Merk, M. Schiller and N. Tuning, Exploring B s → D (∗) ± s K ∓ decays in the presence of a sizable width difference ΔΓs, Nucl. Phys. B 868 (2013) 351 [arXiv:1208.6463] [INSPIRE].
BaBar collaboration, B. Aubert et al., Measurement of time-dependent CP-violating asymmetries and constraints on sin(2β + γ) with partial reconstruction of B → D ∗∓ π ± decays, Phys. Rev. D 71 (2005) 112003 [hep-ex/0504035] [INSPIRE].
BaBar collaboration, B. Aubert et al., Measurement of time-dependent CP asymmetries in B 0 → D (∗)± π ∓ and B 0 → D ± ρ ∓ decays, Phys. Rev. D 73 (2006) 111101 [hep-ex/0602049] [INSPIRE].
Belle collaboration, F.J. Ronga et al., Measurements of CP violation in B 0 → D ∗− π + and B 0 → D − π + decays, Phys. Rev. D 73 (2006) 092003 [hep-ex/0604013] [INSPIRE].
Belle collaboration, S. Bahinipati et al., Measurements of time-dependent CP asymmetries in B → D ∗∓ π ± decays using a partial reconstruction technique, Phys. Rev. D 84 (2011) 021101 [arXiv:1102.0888] [INSPIRE].
Heavy Flavor Averaging Group (HFAG) collaboration, Y. Amhis et al., Averages of b-hadron, c-hadron and τ -lepton properties as of summer 2014, arXiv:1412.7515 [INSPIRE].
L. Wolfenstein, Parametrization of the Kobayashi-Maskawa matrix, Phys. Rev. Lett. 51 (1983) 1945 [INSPIRE].
Particle Data Group collaboration, C. Patrignani et al., Review of particle physics, Chin. Phys. C 40 (2016) 100001 [INSPIRE].
LHCb collaboration, Measurement of CP-violation and the B 0 s meson decay width difference with B 0 s → J/ψK + K − and B 0 s → J/ψπ + π − decays, Phys. Rev. D 87 (2013) 112010 [arXiv:1304.2600] [INSPIRE].
LHCb collaboration, Measurement of CP asymmetry in B 0 s → D ∓ s K ± decays, JHEP 11 (2014) 060 [arXiv:1407.6127] [INSPIRE].
LHCb collaboration, Measurement of the CP asymmetry in \( {B}_s^0-{\overline{B}}_s^0 \) mixing, Phys. Rev. Lett. 117 (2016) 061803 [Addendum ibid. 118 (2017) 129903] [arXiv:1605.09768] [INSPIRE].
M. Pivk and F.R. Le Diberder, SPlot: a statistical tool to unfold data distributions, Nucl. Instrum. Meth. A 555 (2005) 356 [physics/0402083] [INSPIRE].
Y. Xie, sFit: a method for background subtraction in maximum likelihood fit, arXiv:0905.0724 [INSPIRE].
LHCb collaboration, The LHCb detector at the LHC, 2008 JINST 3 S08005 [INSPIRE].
LHCb collaboration, LHCb detector performance, Int. J. Mod. Phys. A 30 (2015) 1530022 [arXiv:1412.6352] [INSPIRE].
R. Aaij et al., Performance of the LHCb vertex locator, 2014 JINST 9 09007 [arXiv:1405.7808] [INSPIRE].
LHCb Outer Tracker Group collaboration, R. Arink et al., Performance of the LHCb outer tracker, 2014 JINST 9 P01002 [arXiv:1311.3893] [INSPIRE].
LHCb RICH Group collaboration, M. Adinolfi et al., Performance of the LHCb RICH detector at the LHC, Eur. Phys. J. C 73 (2013) 2431 [arXiv:1211.6759] [INSPIRE].
R. Aaij et al., The LHCb trigger and its performance in 2011, 2013 JINST 8 P04022 [arXiv:1211.3055] [INSPIRE].
V.V. Gligorov and M. Williams, Efficient, reliable and fast high-level triggering using a bonsai boosted decision tree, 2013 JINST 8 P02013 [arXiv:1210.6861] [INSPIRE].
T. Sjöstrand, S. Mrenna and P.Z. Skands, A brief introduction to PYTHIA 8.1, Comput. Phys. Commun. 178 (2008) 852 [arXiv:0710.3820] [INSPIRE].
T. Sjöstrand, S. Mrenna and P.Z. Skands, PYTHIA 6.4 physics and manual, JHEP 05 (2006) 026 [hep-ph/0603175] [INSPIRE].
I. Belyaev et al., Handling of the generation of primary events in Gauss, the LHCb simulation framework, J. Phys. Conf. Ser. 331 (2011) 032047 [INSPIRE].
D.J. Lange, The EvtGen particle decay simulation package, Nucl. Instrum. Meth. A 462 (2001) 152 [INSPIRE].
P. Golonka and Z. Was, PHOTOS Monte Carlo: a precision tool for QED corrections in Z and W decays, Eur. Phys. J. C 45 (2006) 97 [hep-ph/0506026] [INSPIRE].
GEANT4 collaboration, J. Allison et al., GEANT4 developments and applications, IEEE Trans. Nucl. Sci. 53 (2006) 270 [INSPIRE].
GEANT4 collaboration, S. Agostinelli et al., GEANT4: a simulation toolkit, Nucl. Instrum. Meth. A 506 (2003) 250 [INSPIRE].
M. Clemencic et al., The LHCb simulation application, Gauss: design, evolution and experience, J. Phys. Conf. Ser. 331 (2011) 032023 [INSPIRE].
W.D. Hulsbergen, Decay chain fitting with a Kalman filter, Nucl. Instrum. Meth. A 552 (2005) 566 [physics/0503191] [INSPIRE].
L. Breiman, J.H. Friedman, R.A. Olshen and C.J. Stone, Classification and regression trees. Wadsworth international group, Belmont CA U.S.A., (1984) [INSPIRE].
B.P. Roe, H.-J. Yang, J. Zhu, Y. Liu, I. Stancu and G. McGregor, Boosted decision trees, an alternative to artificial neural networks, Nucl. Instrum. Meth. A 543 (2005) 577 [physics/0408124] [INSPIRE].
T. Skwarnicki, A study of the radiative cascade transitions between the Upsilon-prime and Upsilon resonances, Ph.D. thesis, Institute of Nuclear Physics, Krakow Poland, (1986) [INSPIRE].
K.S. Cranmer, Kernel estimation in high-energy physics, Comput. Phys. Commun. 136 (2001) 198 [hep-ex/0011057] [INSPIRE].
A. Powell et al., Particle identification at LHCb, PoS(ICHEP 2010)020 [INSPIRE].
LHCb collaboration, A new algorithm for identifying the flavour of B 0 s mesons at LHCb, 2016 JINST 11 P05010 [arXiv:1602.07252] [INSPIRE].
LHCb collaboration, Opposite-side flavour tagging of B mesons at the LHCb experiment, Eur. Phys. J. C 72 (2012) 2022 [arXiv:1202.4979] [INSPIRE].
LHCb collaboration, Measurement of CP violation in B 0 → J/ψK 0 S decays, Phys. Rev. Lett. 115 (2015) 031601 [arXiv:1503.07089] [INSPIRE].
T.M. Karbach, G. Raven and M. Schiller, Decay time integrals in neutral meson mixing and their efficient evaluation, arXiv:1407.0748 [INSPIRE].
LHCb collaboration, Precision measurement of the \( {B}_s^0-{\overline{B}}_s^0 \) oscillation frequency with the decay B 0 s → D − s π +, New J. Phys. 15 (2013) 053021 [arXiv:1304.4741] [INSPIRE].
LHCb collaboration, Measurement of the \( {\overline{B}}^0-{B}^0 \) and \( {\overline{B}}_s^0-{B}_s^0 \) production asymmetries in pp collisions at \( \sqrt{s}=7 \) TeV, Phys. Lett. B 739 (2014) 218 [arXiv:1408.0275] [INSPIRE].
LHCb collaboration, Measurement of CP asymmetry in D 0 → K − K + and D 0 → π − π + decays, JHEP 07 (2014) 041 [arXiv:1405.2797] [INSPIRE].
LHCb collaboration, Measurement of the CKM angle γ from a combination of B ± → Dh ± analyses, Phys. Lett. B 726 (2013) 151 [arXiv:1305.2050] [INSPIRE].
Open Access
This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited.
Author information
Authors and Affiliations
Consortia
Corresponding author
Additional information
ArXiv ePrint: 1712.07428
C. Baesso, C. Göbel, V. Salustino Guimaraes are associated to Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil.
N. Beliy, J. He, W. Huang, P.-R. Li, X. Lyu, J. Qin, M. Szymanski, D. Vieira, Q. Xu, Y. Zheng, H. Cai, L. Sun, B. Dey, W. Hu, Y. Wang, Y. Xie, M. Xu, H. Yin, J. Yu are associated to Center for High Energy Physics, Tsinghua University, Beijing, China.
D. A. Milanes, I.A. Monroy, J.A. Rodriguez Lopez are associated to LPNHE, Université Pierre et Marie Curie, Université Paris Diderot, CNRS/IN2P3, Paris, France.
O. Grünberg, M. Heß, N. Meinert, H. Viemann, R. Waldi are associated to Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany.
T. Likhomanenko, A. Malinin, O. Morgunova, A. Nogay, A. Petrov, V. Shevchenko, A. Vagner are associated to Institute of Theoretical and Experimental Physics (ITEP), Moscow, Russia.
L.M. Garcia Martin, L. Henry, F. Martinez Vidal, A. Oyanguren, C. Remon Alepuz, P. Ruiz Valls, J. Ruiz Vidal, C. Sanchez Mayordomo are associated to ICCUB, Universitat de Barcelona, Barcelona, Spain.
C.J.G. Onderwater are associated to Nikhef National Institute for Subatomic Physics, Amsterdam, The Netherlands.
C.L. Da Silva, J.M. Durham are associated to Syracuse University, Syracuse, NY, United States.
Deceased (I. Raniuk).
Rights and permissions
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made.
The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder.
To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/.
About this article
Cite this article
The LHCb collaboration., Aaij, R., Adeva, B. et al. Measurement of CP asymmetry in B 0 s → D ∓ s K± decays. J. High Energ. Phys. 2018, 59 (2018). https://doi.org/10.1007/JHEP03(2018)059
Received:
Accepted:
Published:
DOI: https://doi.org/10.1007/JHEP03(2018)059