Toward extracting from without binning

Jeffrey V. Backus; Marat Freytsis; Yuval Grossman; Stefan Schacht; Jure Zupan

doi:10.1140/epjc/s10052-023-12057-x

2023 Impact factor 4.2

Particles and Fields

Open Access

Eur. Phys. J. C (2023) 83: 877
https://doi.org/10.1140/epjc/s10052-023-12057-x

Regular Article - Theoretical Physics

Toward extracting $γ$ $\gamma$ from $B \to D K$ $B\rightarrow DK$ without binning

Jeffrey V. Backus¹^a, Marat Freytsis¹^,2, Yuval Grossman¹, Stefan Schacht³ and Jure Zupan⁴

¹ LEPP, Department of Physics, Cornell University, 14853, Ithaca, NY, USA
² NHETC, Department of Physics and Astronomy, Rutgers University, 08854, Piscataway, NJ, USA
³ Department of Physics and Astronomy, University of Manchester, M13 9PL, Manchester, UK
⁴ Department of Physics, University of Cincinnati, 45221, Cincinnati, OH, USA

^a jb2134@princeton.edu

Received: 11 August 2023
Accepted: 19 September 2023
Published online: 28 September 2023

Abstract

$B^{\pm} \to D K^{\pm}$ $B^\pm \rightarrow DK^\pm$ transitions are known to provide theoretically clean information about the CKM angle $γ$ $\gamma$ , with the most precise available methods exploiting the cascade decay of the neutral D into CP self-conjugate states. Such analyses currently require binning in the D decay Dalitz plot, while a recently proposed method replaces this binning with the truncation of a Fourier series expansion. In this paper, we present a proof of principle of a novel alternative to these two methods, in which no approximations at the level of the data representation are required. In particular, our new strategy makes no assumptions about the amplitude and strong phase variation over the Dalitz plot. This comes at the cost of a degree of ambiguity in the choice of test statistic quantifying the compatibility of the data with a given value of $γ$ $\gamma$ , with improved choices of test statistic yielding higher sensitivity. While our current proof-of-principle implementation does not demonstrate optimal sensitivity to $γ$ $\gamma$ , its conceptually novel approach opens the door to new strategies for $γ$ $\gamma$ extraction. More studies are required to see if these can be competitive with the existing methods.

© The Author(s) 2023

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