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The forward-backward asymmetry and differences of partial moments in inclusive semileptonic B decays
by Florian Herren
This Submission thread is now published as
Submission summary
| Authors (as registered SciPost users): | Florian Herren |
| Submission information | |
|---|---|
| Preprint Link: | https://arxiv.org/abs/2205.03427v3 (pdf) |
| Date accepted: | 2022-11-28 |
| Date submitted: | 2022-07-12 16:30 |
| Submitted by: | Herren, Florian |
| Submitted to: | SciPost Physics |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
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| Approach: | Phenomenological |
Abstract
Global fits to moments of kinematic distributions measured in inclusive semileptonic $B\rightarrow X_c l \nu_l$ enable the determination of the Cabibbo-Kobayashi-Maskawa matrix element $|V_{cb}|$ together with non-perturbative matrix elements of the heavy quark expansion. In current fits, only two distinct kinematic distributions are employed and, as a consequence, higher moments of these distributions need to be taken into account to extract the relevant non-perturbative matrix elements. The moments of a given distribution are highly correlated and experimental uncertainties increase for higher moments. To address these issues, Turczyk suggested the inclusion of the charged lepton forward-backward asymmetry $\mathcal{A}_{FB}$ in global fits, since it provides information on non-perturbative parameters beyond the commonly used moments. It is possible to construct differences of partial moments of kinematic distributions, which can provide additional information on the non-perturbative parameters beyond $\mathcal{A}_{FB}$ and are studied in this work for the first time. Further, experimental cuts on the four-momentum transfer square are studied and are shown to preserve the shape of the angular distribution, in contrast to commonly used cuts on the lepton energy. Finally, the impact of final-state radiation and experimental lepton identification requirements on measurements of $\mathcal{A}_{FB}$ and differences of partial moments are discussed.
Published as SciPost Phys. 14, 020 (2023)
Reports on this Submission
Report #1 by Anonymous (Referee 1) on 2022-9-9 (Invited Report)
- Cite as: Anonymous, Report on arXiv:2205.03427v3, delivered 2022-09-09, doi: 10.21468/SciPost.Report.5668
Strengths
1-novel computation within the subject matter
2-timely work, given that the ongoing Belle II experiment will be able to measure the newly predicted observable
Weaknesses
none
Report
The author provides predictions for an observable and its kinematic moments in inclusive $B\to X\ell\bar\nu$ decays that had not previously been predicted, albeit discussed, in the literature. The observable is accessible at ongoing HEP experiments, to wit: the Belle II experiment. To me, this already qualifies the manuscript as eligible for publication.
The author discusses very methodically the prospects of an experimental determination of the proposed observable, taking care to investigate potential e.m. effects including final state radiation. He also discusses connections between his findings on the lepton identification for the inclusive decay and published Belle II results on the reconstruction efficiency in the exclusive decay $B\to D^*\ell\bar\nu$. The latter are currently under critical discussion due to a significant breaking $e/\mu$ universality and the manuscript might provide insight to understand this result, thereby increasing the relevance of this manuscript even further.
The manuscript is well written and mostly self contained. In fact, I would argue that it could have been reduced in length by a few pages; however, this does not enter into my recommendation.
Requested changes
none
Author: Florian Herren on 2022-11-08 [id 2998]
(in reply to Report 1 on 2022-09-09)I thank the referee for this report.
I have chosen not to reduce the length of the manuscript to keep it self-contained and to not sacrifice clarity.