Measurements of branching fractions for electromagnetic transitions involving the ${\ensuremath{\chi}}_{bJ}(1P)$ states

Measurements of branching fractions for electromagnetic transitions involving the $χ_{b J} (1 P)$ states

M. Kornicer et al. (CLEO Collaboration)

Phys. Rev. D 83, 054003 – Published 3 March 2011

Abstract

Using (9.32, 5.88) million $Υ (2 S, 3 S)$ decays taken with the CLEO III detector, we obtain five product branching fractions for the exclusive processes $Υ (2 S) \to γ χ_{b 0, 1, 2} (1 P) \to γ γ Υ (1 S)$ and $Υ (3 S) \to γ χ_{b 1, 2} (1 P) \to γ γ Υ (1 S)$ . We observe the transition $χ_{b 0} (1 P) \to γ Υ (1 S)$ for the first time. Using the known branching fractions for $B [Υ (2 S) \to γ χ_{b J} (1 P)]$ , we extract values for $B [χ_{b J} (1 P) \to γ Υ (1 S)]$ for $J = 0$ , 1, 2. In turn, these values can be used to unfold the $Υ (3 S)$ product branching fractions to obtain values for $B [Υ (3 S) \to γ χ_{b 1, 2} (1 P)]$ for the first time individually. Comparison of these with each other and with the branching fraction $B [Υ (3 S) \to γ χ_{b 0}]$ previously measured by CLEO provides tests of relativistic corrections to electric dipole matrix elements.

Received 2 December 2010

DOI:https://doi.org/10.1103/PhysRevD.83.054003

Authors & Affiliations

Click to Expand

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand

Issue

Vol. 83, Iss. 5 — 1 March 2011

Reuse & Permissions

Access Options

Article Available via CHORUS

Download Accepted Manuscript

Author publication services for translation and copyediting assistance advertisement

Images

Figure 1
Distributions of $χ_{m, 4 C}^{2}$ for $Υ (1 S) \to μ^{+} μ^{-}$ candidates (a, b) and $Υ (1 S) \to e^{+} e^{-}$ candidates (c, d) based on events of $Υ (2 S) \to γ γ Υ (1 S)$ candidates (a, c) and $Υ (3 S) \to γ γ Υ (1 S)$ candidates (b, d) via $χ_{b J} (1 P)$ , respectively. Open circles represent data, solid histograms the sum of scaled signal MC and background contributions, where the background levels are indicated by scaled off-resonance data (dotted histogram) and, for $Υ (3 S)$ decays, QED MC simulation (dashed histograms). Solid arrows indicate standard selection criteria, and dashed arrows alternate values used for systematic studies of dependence on selection criteria.
Reuse & Permissions
Figure 2
Fits to data with a flat background shape represented by dashed histograms for $Υ (1 S) \to μ^{+} μ^{-}$ $[e^{+} e^{-}]$ candidates in the two plots (a, b) [(c, d)]. Plots (b) and (d) are identical, respectively, to (a) and (c) but zoomed in so as to highlight the $J = 0$ component. The dotted histograms represent the scaled background shapes based on the off-resonance data. The dot-dashed lines show components of each of the three photon lines.
Reuse & Permissions
Figure 3
Distributions of $E_{γ}^{low}$ versus $E_{γ}^{high}$ based on $Υ (3 S)$ signal MC samples for $J = 0$ (open circles), $J = 1$ (open rectangles), and $J = 2$ (closed triangles) using $μ^{+} μ^{-}$ selection. The diagonal band, edged by lines labeled as $Θ_{γ γ} = π$ (or 0), where $Θ_{γ γ}$ is an opening angle between the two emitted photons, is generated due to our kinematic constraints. The three samples are normalized to our measured production rates in this work while the size of a symbol in a bin is proportional to the number of events for the corresponding $J$ in that bin.
Reuse & Permissions
Figure 4
Distributions of $E_{γ}^{low}$ versus $E_{γ}^{high}$ based on the on- $Υ (3 S)$ data. Open triangles (closed rectangles) represent data points based on $e^{+} e^{-}$ ( $μ^{+} μ^{-}$ ) selection. The size of each symbol is proportional to the number of events in the bin.
Reuse & Permissions
Figure 5
Projections from the nominal fit to data onto (a,c) $E_{γ}^{low}$ and (b,d) $E_{γ}^{high}$ axes for data using the (a,b) $μ^{+} μ^{-}$ and (c,d) $e^{+} e^{-}$ selections. The dashed histograms represent signal photons via $χ_{b J} (1 P)$ . The dotted histograms represent the QED MC sample contribution as normalized by the fit, and the solid histogram is the sum of background and signal histograms.
Reuse & Permissions
Figure 6
Illustration of ratios of suppressed $E 1$ transition rates, $Γ_{J = 1} / Γ_{J = 0}$ (circles), $Γ_{J = 2} / Γ_{J = 0}$ (squares), and $Γ_{J = 2} / Γ_{J = 1}$ (triangles) from Table 9.
Reuse & Permissions

Physical Review D

covering particles, fields, gravitation, and cosmology

Measurements of branching fractions for electromagnetic transitions involving the $χ_{b J} (1 P)$ states

M. Kornicer et al. (CLEO Collaboration)

Phys. Rev. D 83, 054003 – Published 3 March 2011

Abstract

Authors & Affiliations

Article Text (Subscription Required)

References (Subscription Required)

Issue

Access Options

Physical Review D

covering particles, fields, gravitation, and cosmology

Measurements of branching fractions for electromagnetic transitions involving the χbJ(1P) states

M. Kornicer et al. (CLEO Collaboration)

Phys. Rev. D 83, 054003 – Published 3 March 2011

Abstract

Authors & Affiliations

Article Text (Subscription Required)

References (Subscription Required)

Issue

Access Options

Authorization Required

Other Options

Download & Share

Images

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Log In

Search

Article Lookup

Paste a citation or DOI

Enter a citation

Measurements of branching fractions for electromagnetic transitions involving the $χ_{b J} (1 P)$ states