Catalog · Secondary · B014

B014 $B\to \rho\gamma, B\to \omega\gamma$

Exclusive radiative b $ \to $ d $\gamma$ decays

Status REVIEWED VERIFIED High Code: NO Priority Low

PDG / equivalent values

Observable	Value	Year	Experiment / source	Provenance
B(B+ $ \to \rho+ \gamma$)	(9.8 +/- 2.5) x 10^-7	2025	PDG Review of Particle Physics, B+/- listing, 2025 update	source ↑
B(B0 $ \to $ rho0 $\gamma$)	(8.6 +/- 1.5) x 10^-7	2025	PDG Review of Particle Physics, B0 listing, 2025 update	source ↑
B(B0 $ \to \omega \gamma$)	(4.4 +1.8 -1.6) x 10^-7	2025	PDG Review of Particle Physics, B0 listing, 2025 update	source ↑
B(B $ \to \rho \gamma$)	(1.40 +/- 0.22) x 10^-6	2024	HFLAV rare decays, end-of-year 2024	source ↑
B(B $ \to \rho/\omega \gamma$)	(1.30 +/- 0.18) x 10^-6	2024	HFLAV rare decays, end-of-year 2024	source ↑
$\Gamma(B+ \to \rho+ \gamma$) / [2 $\Gamma(B0 \to $ rho0 $\gamma)]$ - 1	-0.46 dimensionless	2024	HFLAV rare decays, end-of-year 2024	source ↑
B(B $ \to $ Xd $\gamma$)	(9.2 +/- 3.0) x 10^-6	2024	HFLAV rare decays, end-of-year 2024	source ↑
$A_{CP}(B+ \to \rho+ \gamma$)	-0.11 dimensionless	2025	PDG Review of Particle Physics, B+/- listing, 2025 update	source ↑
C(B0 $ \to $ rho0 $\gamma$)	0.44 dimensionless	2025	PDG Review of Particle Physics, B0 listing, 2025 update	source ↑
S(B0 $ \to $ rho0 $\gamma$)	-0.83 dimensionless	2025	PDG Review of Particle Physics, B0 listing, 2025 update	source ↑
B(B+ $ \to \rho+ \gamma$)	(13.1 +2.0 +1.3 -1.9 -1.2) x 10^-7	2024	arXiv:2407.08984	source ↑
B(B0 $ \to $ rho0 $\gamma$)	(7.5 +/- 1.3 +1.0 -0.8) x 10^-7	2024	arXiv:2407.08984	source ↑
$A_I(B \to \rho \gamma$)	(10.9 +11.2 +7.8 -11.7 -7.3)%	2024	arXiv:2407.08984	source ↑
$A_{CP}(B+ \to \rho+ \gamma$)	(-8.2 +/- 15.2 +1.6 -1.2)%	2024	arXiv:2407.08984	source ↑
B(B0 $ \to \rho(770)0 \gamma$) / B(B0 $ \to $ K*(892)0 $\gamma$)	0.0189 dimensionless	2025	arXiv:2507.14401	source ↑
B(B0 $ \to \rho(770)0 \gamma$)	(7.9 +/- 0.3 +/- 0.2 +/- 0.2) x 10^-7	2025	arXiv:2507.14401	source ↑

Why this constrains the RS scan

This this catalog wave entry is SECONDARY under flavor\_catalog/PRIORITY\_TIERS.md. In an RS/anarchic-flavor treatment the relevant short-distance objects are the $b\to d$ electromagnetic and chromomagnetic dipole coefficients $C_7^{(d)}$, $C_7^{\prime(d)}$, $C_8^{(d)}$, and $C_8^{\prime(d)}$. KK gauge bosons, KK fermions, and Higgs-sector loops can induce chirality-flipped dipoles whose amplitudes depend on 5D fermion localization and anarchic Yukawa insertions. Compared with B011/B012, this entry tests the same dipole machinery in the $b\to d$ flavor direction, where the exclusive isospin and CP observables can be sensitive to right-handed photons, spectator effects, and weak-annihilation contamination.

What's changed since the original paper

BaBar arXiv:1005.4087 extended the 2008 Belle/BaBar exclusive picture by studying semi-inclusive $B\to X_{s,d}\gamma$ and extracting $|V_{td}/V_{ts}|$. Hurth and Nakao arXiv:1005.1224 is the compact post-2008 review of how inclusive and exclusive $b\to d\gamma$ data are compared with $b\to s\gamma$. Belle/Belle II arXiv:2407.08984 provides a newer joint $B\to\rho\gamma$ measurement with CP and isospin asymmetries, while LHCb arXiv:2507.14401 reports a high-precision $B^0\to\rho(770)^0\gamma$ branching fraction normalized to $B^0\to K^{*0}\gamma$. These are important for a future likelihood update even though the canonical PDG/HFLAV snapshot values above remain the conservative catalog anchors. Descotes-Genon et al. arXiv:1104.3342 gives the standard $C_7$-$C_7'$ language for radiative $B$ constraints, and Bharucha--Straub--Zwicky arXiv:1503.05534 supplies updated $B\to\rho$ and $B\to\omega$ form-factor inputs from light-cone sum rules. These sources matter because an exclusive $B\to\rho/\omega\gamma$ constraint is only as clean as its dipole matching, RG evolution, and form-factor/annihilation prescription.

Validity and model dependence

Class: useful but model-dependent. The inclusive $b\to d\gamma$ rate and the exclusive $B\to\rho/\omega\gamma$ averages constrain $|C_7^{(d)}|^2$ and $|C_7^{\prime(d)}|^2$ combinations only after choosing CKM inputs, exclusive form factors, weak-annihilation treatment, and a convention for SM long-distance pieces. The isospin asymmetry should be treated as diagnostic unless the implementation includes spectator and annihilation effects. The LHCb 2025 measurement also carries an explicit saturation assumption for the selected $\rho(770)^0$ and $K^{*}(892)^0$ dihadron spectra. A hard RS exclusion should therefore come from a dedicated Wilson-coefficient likelihood, not from a direct comparison of raw branching fractions alone.

Code coverage in this repo

NO. A focused search across quarkConstraints/, qcd/, flavorConstraints/, neutrinos/, yukawa/, warpConfig/, solvers/, scanParams/, and tests/ for $B\to\rho\gamma$, $B\to\omega\gamma$, $b\to d\gamma$, $X_d\gamma$, and B014 returned no matches. Broader dipole searches find only lepton-sector coverage, for example flavorConstraints/muToEGamma.py:75 and flavorConstraints/README.md:3. The modern quark policy surface at quarkConstraints/modern/phenomenology.py:23 enumerates only $\varepsilon_K$, $K$, $B_d$, $B_s$, and $D^0$ mixing systems; the $\Delta F=2$ beauty routines at quarkConstraints/deltaf2.py:903, quarkConstraints/deltaf2.py:922, and quarkConstraints/deltaf2.py:941 do not implement radiative $b\to d\gamma$ decays.

Linked evidence (opens GitHub blob at flavor-catalog-website/2026q2):

Implementation difficulty

HIGH. The repo would need new $b\to d\gamma$ dipole matching, running and mixing for $C_7^{(d)}$, $C_7^{\prime(d)}$, $C_8^{(d)}$, and $C_8^{\prime(d)}$, a bridge from RS overlap/Yukawa data into those coefficients, and an exclusive $B\to\rho/\omega\gamma$ likelihood with form-factor, isospin, CP, and CKM-ratio uncertainties. Existing $\Delta F=2$ and $\mu\to e\gamma$ code cannot be reused as a finished constraint.

Reason: Requires new $b \to d \gamma$ electromagnetic/chromomagnetic dipole matching, C7/C7' and C8/C8' RG treatment, exclusive $B \to \rho/\omega$ form-factor and annihilation inputs, and a likelihood for branching fractions, isospin, CP, and CKM-ratio observables.

Key references

Process-local source keys before bibliography consolidation: hflav\_rare\_decays\_dec2024\_bd\_gamma, pdg2025\_bplus\_rhop\_gamma, pdg2025\_bzero\_rho\_omega\_gamma, babar\_2008\_rho\_omega\_gamma, belle\_2008\_bd\_gamma, babar\_2010\_xdgamma, hurth\_nakao\_2010\_penguins, descotes\_genon\_2011\_c7\_c7prime, bharucha\_straub\_zwicky\_2016\_lcsr, belle\_belleii\_2024\_rhogamma, lhcb\_2025\_b0rho0gamma, and cfw\_2008\_rs\_flavor.

display (9.8 +/- 2.5) x 10^-7

RESOLVED

Match snapshot line 10

L7:   S. Navas et al. (Particle Data Group), Phys. Rev. D 110, 030001 (2024) and 2025 update.
L8: 
L9: Summary table extract, light unflavored meson modes:
L10:   Gamma 518 rho+ gamma  (9.8 +/- 2.5) x 10^-7.
L11: 
L12: Detailed entry extract:
L13:   Gamma rho+ gamma / Gamma_total, Gamma 518 / Gamma.

display (8.6 +/- 1.5) x 10^-7

RESOLVED

Match snapshot line 10

L7:   S. Navas et al. (Particle Data Group), Phys. Rev. D 110, 030001 (2024) and 2025 update.
L8: 
L9: Summary table extract, light unflavored meson modes:
L10:   Gamma 417 rho0 gamma   (8.6 +/- 1.5) x 10^-7.
L11:   Gamma 419 omega gamma  (4.4 +1.8 -1.6) x 10^-7.
L12: 
L13: Detailed entry extract:

display (4.4 +1.8 -1.6) x 10^-7

RESOLVED

Match snapshot line 11

L8: 
L9: Summary table extract, light unflavored meson modes:
L10:   Gamma 417 rho0 gamma   (8.6 +/- 1.5) x 10^-7.
L11:   Gamma 419 omega gamma  (4.4 +1.8 -1.6) x 10^-7.
L12: 
L13: Detailed entry extract:
L14:   Gamma rho0 gamma / Gamma_total, Gamma 417 / Gamma.

display (1.40 +/- 0.22) x 10^-6

RESOLVED

Match snapshot line 12

L9: B(B -> Xd gamma)  BaBar [297]  9.2 +/- 2.0 +/- 2.3; average 9.2 +/- 3.0.
L10: 
L11: B(B -> rho gamma)^7:
L12:   Belle [279]  1.21 +0.24 -0.22 +/- 0.12; HFLAV average 1.40 +/- 0.22.
L13:   BaBar [257]  1.73 +0.34 -0.32 +/- 0.17; PDG average 1.39 +0.25 -0.24.
L14: 
L15: B(B -> rho/omega gamma)^7:

display (1.30 +/- 0.18) x 10^-6

AMBIGUOUS

Match 1 of 3 snapshot line 13

L10: 
L11: B(B -> rho gamma)^7:
L12:   Belle [279]  1.21 +0.24 -0.22 +/- 0.12; HFLAV average 1.40 +/- 0.22.
L13:   BaBar [257]  1.73 +0.34 -0.32 +/- 0.17; PDG average 1.39 +0.25 -0.24.
L14: 
L15: B(B -> rho/omega gamma)^7:
L16:   Belle [279]  1.14 +/- 0.20 +0.10 -0.12; HFLAV average 1.30 +/- 0.18.

Match 2 of 3 snapshot line 16

L13:   BaBar [257]  1.73 +0.34 -0.32 +/- 0.17; PDG average 1.39 +0.25 -0.24.
L14: 
L15: B(B -> rho/omega gamma)^7:
L16:   Belle [279]  1.14 +/- 0.20 +0.10 -0.12; HFLAV average 1.30 +/- 0.18.
L17:   BaBar [257]  1.63 +0.30 -0.28 +/- 0.16; PDG average 1.30 +0.23 -0.24.
L18: 
L19: Footnote 7: "The PDG uncertainty includes a scale factor."

Match 3 of 3 snapshot line 17

L14: 
L15: B(B -> rho/omega gamma)^7:
L16:   Belle [279]  1.14 +/- 0.20 +0.10 -0.12; HFLAV average 1.30 +/- 0.18.
L17:   BaBar [257]  1.63 +0.30 -0.28 +/- 0.16; PDG average 1.30 +0.23 -0.24.
L18: 
L19: Footnote 7: "The PDG uncertainty includes a scale factor."
L20:

fallback_value_uncertainty Gamma(B+ -> rho+ gamma) / [2 Gamma(B0 -> rho0 gamma)] - 1 = -0.46 +- 0.17

RESOLVED

Match snapshot line 30

L27:   Belle [279]  -0.48 +0.21 -0.19 +0.08 -0.09
L28:   BaBar [257]  -0.43 +0.25 -0.22 +/- 0.10
L29: Average:
L30:   HFLAV -0.46 +/- 0.17; PDG -0.46 +0.17 -0.16.
L31: 
L32: Relevant HFLAV bibliography entries:
L33:   [256] Belle II/Belle Collaboration, I. Adachi et al., "Measurement of branching fractions, CP asymmetry, and isospin asymmetry for B -> rho gamma decays using Belle and Belle II data", arXiv:2407.08984.

display (9.2 +/- 3.0) x 10^-6

RESOLVED

Match snapshot line 9

L6: Relevant extract from Table 67, "Branching fractions of radiative, FCNC decays..."
L7: Units in the table header: [10^-6].
L8: 
L9: B(B -> Xd gamma)  BaBar [297]  9.2 +/- 2.0 +/- 2.3; average 9.2 +/- 3.0.
L10: 
L11: B(B -> rho gamma)^7:
L12:   Belle [279]  1.21 +0.24 -0.22 +/- 0.12; HFLAV average 1.40 +/- 0.22.

fallback_value_uncertainty A_CP(B+ -> rho+ gamma) = -0.11 +- {'statistical': 0.32, 'systematic': 0.09}

AMBIGUOUS

Match 1 of 2 snapshot line 17

L14:   VALUE (units 10^-6):
L15:     0.98 +/- 0.25  OUR AVERAGE
L16:     1.20 +0.42 -0.37 +/- 0.20  AUBERT 08BH BABR
L17:     0.87 +0.29 -0.27 +0.09 -0.11  TANIGUCHI 08 BELL
L18: 
L19: Direct CP entry extract:
L20:   ACP(B+ -> rho+ gamma):

Match 2 of 2 snapshot line 21

L18: 
L19: Direct CP entry extract:
L20:   ACP(B+ -> rho+ gamma):
L21:     -0.11 +/- 0.32 +/- 0.09  TANIGUCHI 08 BELL.

fallback_value_uncertainty C(B0 -> rho0 gamma) = 0.44 +- {'statistical': 0.49, 'systematic': 0.14}

AMBIGUOUS

Match 1 of 2 snapshot line 23

L20: 
L21:   Gamma omega gamma / Gamma_total, Gamma 419 / Gamma.
L22:   VALUE (units 10^-6):
L23:     0.44 +0.18 -0.16  OUR AVERAGE
L24:     0.50 +0.27 -0.23 +/- 0.09  AUBERT 08BH BABR
L25:     0.40 +0.19 -0.17 +/- 0.13  TANIGUCHI 08 BELL
L26:

Match 2 of 2 snapshot line 29

L26: 
L27: Time-dependent CP entries:
L28:   C(B0 -> rho0 gamma):
L29:     0.44 +/- 0.49 +/- 0.14  USHIRODA 08 BELL.
L30:     PDG note: reports value of A which is equal to -C.
L31:   S(B0 -> rho0 gamma):
L32:     -0.83 +/- 0.65 +/- 0.18  USHIRODA 08 BELL.

fallback_value_uncertainty S(B0 -> rho0 gamma) = -0.83 +- {'statistical': 0.65, 'systematic': 0.18}

RESOLVED

Match snapshot line 32

L29:     0.44 +/- 0.49 +/- 0.14  USHIRODA 08 BELL.
L30:     PDG note: reports value of A which is equal to -C.
L31:   S(B0 -> rho0 gamma):
L32:     -0.83 +/- 0.65 +/- 0.18  USHIRODA 08 BELL.

display (13.1 +2.0 +1.3 -1.9 -1.2) x 10^-7

RESOLVED

Match snapshot line 12

L9: Abstract-page value extract:
L10:   Data samples: 772 x 10^6 B Bbar pairs from Belle and 387 x 10^6 B Bbar pairs from Belle II at the Upsilon(4S).
L11:   Fitted yields: 114 +/- 12 B+ -> rho+ gamma decays and 99 +/- 12 B0 -> rho0 gamma decays.
L12:   B(B+ -> rho+ gamma) = (13.1 +2.0 +1.3 -1.9 -1.2) x 10^-7.
L13:   B(B0 -> rho0 gamma) = (7.5 +/- 1.3 +1.0 -0.8) x 10^-7.
L14:   First uncertainty is statistical and second is systematic.
L15:   A_I(B -> rho gamma) = (10.9 +11.2 +7.8 -11.7 -7.3)%.

display (7.5 +/- 1.3 +1.0 -0.8) x 10^-7

RESOLVED

Match snapshot line 13

L10:   Data samples: 772 x 10^6 B Bbar pairs from Belle and 387 x 10^6 B Bbar pairs from Belle II at the Upsilon(4S).
L11:   Fitted yields: 114 +/- 12 B+ -> rho+ gamma decays and 99 +/- 12 B0 -> rho0 gamma decays.
L12:   B(B+ -> rho+ gamma) = (13.1 +2.0 +1.3 -1.9 -1.2) x 10^-7.
L13:   B(B0 -> rho0 gamma) = (7.5 +/- 1.3 +1.0 -0.8) x 10^-7.
L14:   First uncertainty is statistical and second is systematic.
L15:   A_I(B -> rho gamma) = (10.9 +11.2 +7.8 -11.7 -7.3)%.
L16:   A_CP(B+ -> rho+ gamma) = (-8.2 +/- 15.2 +1.6 -1.2)%.

display (10.9 +11.2 +7.8 -11.7 -7.3)%

RESOLVED

Match snapshot line 15

L12:   B(B+ -> rho+ gamma) = (13.1 +2.0 +1.3 -1.9 -1.2) x 10^-7.
L13:   B(B0 -> rho0 gamma) = (7.5 +/- 1.3 +1.0 -0.8) x 10^-7.
L14:   First uncertainty is statistical and second is systematic.
L15:   A_I(B -> rho gamma) = (10.9 +11.2 +7.8 -11.7 -7.3)%.
L16:   A_CP(B+ -> rho+ gamma) = (-8.2 +/- 15.2 +1.6 -1.2)%.
L17: 
L18: Role for B014: post-2008 Belle/Belle II update; HFLAV Dec. 2024 cites it, but the Table 67 averages quoted for B014 still use the older Belle/BaBar rows.

display (-8.2 +/- 15.2 +1.6 -1.2)%

RESOLVED

Match snapshot line 16

L13:   B(B0 -> rho0 gamma) = (7.5 +/- 1.3 +1.0 -0.8) x 10^-7.
L14:   First uncertainty is statistical and second is systematic.
L15:   A_I(B -> rho gamma) = (10.9 +11.2 +7.8 -11.7 -7.3)%.
L16:   A_CP(B+ -> rho+ gamma) = (-8.2 +/- 15.2 +1.6 -1.2)%.
L17: 
L18: Role for B014: post-2008 Belle/Belle II update; HFLAV Dec. 2024 cites it, but the Table 67 averages quoted for B014 still use the older Belle/BaBar rows.

fallback_value_uncertainty B(B0 -> rho(770)0 gamma) / B(B0 -> K*(892)0 gamma) = 0.0189 +- {'statistical': 0.0007, 'systematic': 0.0005}

RESOLVED

Match snapshot line 14

L11:   Data sample: proton-proton collision data at 7, 8, and 13 TeV, integrated luminosity 9 fb^-1.
L12:   Ratio:
L13:     B(B0 -> rho(770)0 gamma) / B(B0 -> K*(892)0 gamma)
L14:       = 0.0189 +/- 0.0007 +/- 0.0005.
L15:   Branching fraction:
L16:     B(B0 -> rho(770)0 gamma) = (7.9 +/- 0.3 +/- 0.2 +/- 0.2) x 10^-7.
L17:   First uncertainty is statistical, second systematic, and last from the normalisation mode.

display (7.9 +/- 0.3 +/- 0.2 +/- 0.2) x 10^-7

RESOLVED

Match snapshot line 16

L13:     B(B0 -> rho(770)0 gamma) / B(B0 -> K*(892)0 gamma)
L14:       = 0.0189 +/- 0.0007 +/- 0.0005.
L15:   Branching fraction:
L16:     B(B0 -> rho(770)0 gamma) = (7.9 +/- 0.3 +/- 0.2 +/- 0.2) x 10^-7.
L17:   First uncertainty is statistical, second systematic, and last from the normalisation mode.
L18:   The result assumes that rho(770)0 and K*(892)0 decays saturate the dihadron mass spectra considered in the analysis.
L19:   The abstract describes the result as consistent with the current world average and by far the most precise measurement to date.