Extracting $B \to K^*$ Form Factors from Data

Christian Hambrock; Gudrun Hiller

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Extracting $B \to K^*$ Form Factors from Data

Christian Hambrock, Gudrun Hiller

High Energy Physics - Phenomenology · Submitted 19 Apr 2012

abstract compiled · 2026-09-23 · no language-model review

The authors' main claim We extract ratios of $B \to K^*$ form factors at low hadronic recoil from recent data on $B \to K^* \mu^+ \mu^-$ decays in a model-independent way.

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We extract ratios of $B \to K^*$ form factors at low hadronic recoil from recent data on $B \to K^* \mu^+ \mu^-$ decays in a model-independent way. The presented method will improve in the future with further (angular) studies in semileptonic rare B-decays and advance our understanding of form factors, which are important inputs in precision tests of the Standard Model.

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#	sentence	role	the authors' own work	states the main conclusion	strength
s0	We extract ratios of $B \to K^$ form factors at low hadronic recoil from recent data on $B \to K^ \mu^+ \mu^-$ decays in a model-independent way.	contribution 0.88	0.95	0.83	asserted 1.00
s1	The presented method will improve in the future with further (angular) studies in semileptonic rare B-decays and advance our understanding of form factors, which are important inputs in precision tests of the Standard Model.	future work 0.99	0.10	0.11	hedged possibility 0.55

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The paper

Original abstract

We extract ratios of $B \to K^*$ form factors at low hadronic recoil from recent data on $B \to K^* \mu^+ \mu^-$ decays in a model-independent way. The presented method will improve in the future with further (angular) studies in semileptonic rare B-decays and advance our understanding of form factors, which are important inputs in precision tests of the Standard Model.

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References

Forward citations

Cited by 10 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score. Full citation record

Angular Analysis of the Decay $\Lambda_b \to \Lambda (\to N \pi) \ell^+\ell^-$
hep-ph 2014-10 accept novelty 6.0 of 10

The full angular distribution of Lambda_b to Lambda(-> N pi) l+ l- yields ten angular observables, two of which (X1, X2) probe right-handed b to s couplings that B to K* l+ l- cannot access.
Disentangling the Decay Observables in $B^- \to \pi^+\pi^-\ell^-\bar\nu_\ell$
hep-ph 2013-10 accept novelty 6.0 of 10

The paper derives the complete angular decomposition of B- to pi+ pi- l- nu-bar and a set of algebraic null tests that would reveal non-standard (V+A, scalar, or tensor) structure in b to u transitions.
Lattice QCD calculation of form factors describing the rare decays $B \to K^* \ell^+ \ell^-$ and $B_s \to \phi \ell^+ \ell^-$
hep-lat 2013-10 accept novelty 6.0 of 10

Full-QCD lattice calculations with 2+1 dynamical quark flavors and NRQCD bottom quarks determine the B to K* and Bs to phi form factors at low recoil with roughly 5 percent total systematic uncertainty.
General Analysis of B -> K^(*) l^+ l^- Decays at Low Recoil
hep-ph 2012-12 accept novelty 6.0 of 10

At low hadronic recoil, the transversity observables H_T^(1,3,4,5) stay free of hadronic matrix elements even with the full dimension-six operator basis, and J_7 probes the operator product expansion at the few-percent level.
Comprehensive Bayesian Analysis of Rare (Semi)leptonic and Radiative B Decays
hep-ph 2013-10 conditional novelty 5.0 of 10

A Bayesian global fit of rare B decay data prefers the Standard Model over new physics in C7, C9, C10 and their chirality-flipped partners, once 15 percent power corrections are permitted.

Show 5 more citing papers

B -> K^* Form Factors from Flavor Data to QCD and Back
hep-ph 2013-08 accept novelty 5.0 of 10

Form factor ratios extracted from B to K-star dilepton angular data at low recoil, combined with heavy-quark symmetry and LCSR input, yield Standard-Model-consistent predictions for A_FB and P'_5.
Optimizing the basis of B->K*ll observables in the full kinematic range
hep-ph 2013-03 accept novelty 5.0 of 10

The authors define an optimal basis of form-factor-insensitive angular observables for B → K*ℓ+ℓ− and provide binned Standard Model predictions for both CP-averaged and CP-violating quantities.
Bayesian Fit of Exclusive $b \to s \bar\ell\ell$ Decays: The Standard Model Operator Basis
hep-ph 2012-05 conditional novelty 5.0 of 10

A full Bayesian fit of the Wilson coefficients C7, C9 and C10 to exclusive rare B decays finds a Standard-Model-like and a sign-flipped solution with roughly equal posterior weight, and no evidence requiring new physics.
Implications of LHCb measurements and future prospects
hep-ex 2012-08 accept novelty 4.0 of 10

LHCb's first 1.0 fb^-1 of 7 TeV data already constrain several new-physics scenarios, and a proposed upgrade to 50 fb^-1 would sharpen those constraints by roughly an order of magnitude.
Cornering New Physics in b --> s Transitions
hep-ph 2012-06 conditional novelty 4.0 of 10

A global fit to 2012 rare B decay data finds all b to s Wilson coefficients consistent with the Standard Model at 95% confidence, with sharply improved bounds on chirality-flipped operators from B to K mu mu and the L...

How the literature uses it

22 arXiv papers cite this in 37 sentences

Each citing sentence is taken from the citing paper's LaTeX source and typed by Pith's classifier. A label appears at probability 0.8 or more (0.95 for support), a contest at 0.7 or more; the quoted words are the citing authors'. How each label was checked · JSON

Papers citing it · 30 sentences without a confident label

Uses its method or tool 2 papers

Following Ref. [ref] , we parametrize the transversity form factors $f_i$, $i=⊥,0,∥$ in $B →K^* ℓ^+ ℓ^-$ decays through a Series Expansion (SE) [ref] [equation] in the variable $z$ defined as [equation] Here, $t$ denotes the analytic continuation of $q^2$ to the complex plane, $t_±=(m_B ±m_K^*)^2$ and $t_0$ is a free parameter in the range $0 ≤t_0<t_+$ for which a common choice is $t_0 = t_opt$ with $t_opt=t_+ (1 - √(1 - t_-/t_+))$ [ref] .

B -> K^* Form Factors from Flavor Data to QCD and Back · Form factor series expansion · 0.98
Anticipating this, and following similar procedures adopted in the analysis of the data in the $B →(K, K^*) ℓ^+ ℓ^-$ decays [ref] we present here results for the partial branching ratios $dB (B^+ →π^+ μ^+ μ^-)/dq^2$, binned over specified ranges $[q^2_min, q^2_max]$ in eight $q^2$-intervals.

Precise Calculation of the Dilepton Invariant-Mass Spectrum and the Decay Rate in $B^\pm \to \pi^\pm \mu^+ \mu^-$ in the SM · Introduction · 0.85

Uses its data or values 1 paper

The best-fit result in the lowest order series expansion (SE) is obtained as $α_∥/α_⊥=0.43^+0.11_-0.08, α_0/α_⊥=0.15^+0.03_-0.02$ [ref] .

B -> K(*) l+ l- @ Low Recoil and Physics Implications · $B →K^*$ form factors data versus theory · 0.87

Compares with it 1 paper

* The results in plain SE1 are consistent with the previous findings of Ref. [ref] , but not equal due to the different $B →K^* ℓ^+ ℓ^-$data.

B -> K^* Form Factors from Flavor Data to QCD and Back · Results · 1.00

Cites it as background 2 papers

In particular, the $B →K^*(→Kπ) μ^+ μ^-$ decay offers a large number of observables to test the SM, ranging from the differential decay widths, polarizations, to a full analysis of angular distributions of the final state particles, for an incomplete list one can refer to Refs. [ref] and many references therein.

Implications of the $R_K$ and $R_{K^*}$ anomalies · Introduction · 1.00
The data are presently being combined with theoretical and phenomenological calculations in order to test the Standard Model and to constrain classes of BSM models [ref] .

Lattice QCD calculation of form factors describing the rare decays $B \to K^* \ell^+ \ell^-$ and $B_s \to \phi \ell^+ \ell^-$ · Introduction · 0.80

What it cites · 26 sentences without a confident label

Uses the method or tool of 8 papers

Using the parametrization of the Simplified Series Expansion (SSE) [ref] , corresponding to the changes $B(t) →1-t/m_R^2$, $ϕ_f(t) →1$, $√(-z(t,0)) →√(t)/m_B$, $√(z(t,t_-)) →√(λ̂)$ in Eq. ([ref]), a similarly good fit ist obtained with $χ_min^2=3.4$ and the best-fit results [equation]

Model-independent description of $B\to \pi l\nu$ decays and a determination of $|V_{ub}|$ · Introduction · 0.98
For an analytic ansatz for the $q^2$-shape of the form factors we employ the Series Expansion (SE) [ref] .

A Precision Model Independent Determination of |Vub| from B -> pi e nu · Introduction · 1.00
For an analytic ansatz for the $q^2$-shape of the form factors we employ the Series Expansion (SE) [ref] .

Comment on form factor shape and extraction of |V_ub| from B --> pi l nu · Introduction · 1.00

Uses data or values from 1 paper

Two of these short-distance free observables, the fraction of longitudinally polarized vector mesons $F_L$ and the transverse asymmetry $A_T^(2)$ [ref] , have recently been measured by CDF [ref] , BaBar [ref] ($F_L$ only) and LHCb [ref] in the decay $B →K^* μ^+ μ^-$.

Measurements of the Angular Distributions in the Decays B -> K(*) mu+ mu- at CDF · Introduction · 0.81

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