TY - JOUR

T1 - S-waves and the measurement of βs in Bs decays

AU - Stone, Sheldon

N1 - Funding Information:
I thank the U. S. National Science Foundation for support and L. Zhang for his collaboration on this work.
Publisher Copyright:
© Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence.

PY - 2010

Y1 - 2010

N2 - The CP Violating asymmetry in Bs mixing (βs) is one of the most promising measurements where physics beyond the Standard Model could be revealed. As such, analyses need to be subjected to great scrutiny. The mode Bs → J/ψφ has been used, and the mode Bs → φφ proposed for future measurements. These modes both have two vector particles in the final state and thus angular analyses must be used to disentangle the contributions from CP+ and CP− configurations. The angular distributions, however, could be distorted by the presence of S-waves masquerading as low mass K+K− pairs, that could result in erroneous values of βs. The S-waves could well be the result of a final state formed from an s-quark s-quark pair in a 0+ spin-parity state, such as the f0(980) meson. Data driven and theoretical estimates of the Bs decay rate into the CP+ final state J/ψ f0(980) are given, when f0 → π+π−. The S-wave contribution in J/ψφ should be taken into account when determining βs by including a K+K− S-wave amplitude in the fit. This may change the central value of current results and will also increase the statistical uncertainty. Importantly, the J/ψ f0(980) mode has been suggested as an alternative channel for measuring βs. An expanded version of this paper is available at arXiv:1009.4939 [hep-ph].

AB - The CP Violating asymmetry in Bs mixing (βs) is one of the most promising measurements where physics beyond the Standard Model could be revealed. As such, analyses need to be subjected to great scrutiny. The mode Bs → J/ψφ has been used, and the mode Bs → φφ proposed for future measurements. These modes both have two vector particles in the final state and thus angular analyses must be used to disentangle the contributions from CP+ and CP− configurations. The angular distributions, however, could be distorted by the presence of S-waves masquerading as low mass K+K− pairs, that could result in erroneous values of βs. The S-waves could well be the result of a final state formed from an s-quark s-quark pair in a 0+ spin-parity state, such as the f0(980) meson. Data driven and theoretical estimates of the Bs decay rate into the CP+ final state J/ψ f0(980) are given, when f0 → π+π−. The S-wave contribution in J/ψφ should be taken into account when determining βs by including a K+K− S-wave amplitude in the fit. This may change the central value of current results and will also increase the statistical uncertainty. Importantly, the J/ψ f0(980) mode has been suggested as an alternative channel for measuring βs. An expanded version of this paper is available at arXiv:1009.4939 [hep-ph].

UR - http://www.scopus.com/inward/record.url?scp=85053813934&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85053813934&partnerID=8YFLogxK

M3 - Conference article

AN - SCOPUS:85053813934

VL - 120

JO - Proceedings of Science

JF - Proceedings of Science

SN - 1824-8039

T2 - 35th International Conference of High Energy Physics, ICHEP 2010

Y2 - 22 July 2010 through 28 July 2010

ER -