First observation of the radiative decay ${\Lambda }_b^0\to \Lambda \gamma$

Abstract

The radiative decay ${\Lambda }_b^0\to \Lambda \gamma$ is observed for the first time using a data sample of proton-proton collisions corresponding to an integrated luminosity of $1.7f{b}^{-1}$ collected by the LHCb experiment at a center-of-mass energy of $13TeV$. Its branching fraction is measured exploiting the $B^0\to K^{\ast 0}\gamma$ decay as a normalization mode and is found to be $\mathcal{B}({\Lambda }_b^0\to \Lambda \gamma )=(7.1\pm 1.5\pm 0.6\pm 0.7)\times 10^{-6}$, where the quoted uncertainties are statistical, systematic and systematic from external inputs, respectively. This is the first observation of a radiative decay of a beauty baryon.

arXiv commentAll figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2019-010.html

References in corpus (41)

• Scikit-learn: Machine Learning in Python
• PYTHIA 6.4 Physics and Manual
• PYTHIA 6.2 Physics and Manual
• A Brief Introduction to PYTHIA 8.1
• Averages of $b$-hadron, $c$-hadron, and $\tau$-lepton properties as of summer 2016
• LHCb Detector Performance
• PHOTOS Monte Carlo: a precision tool for QED corrections in Z and W decays
• sPlot: a statistical tool to unfold data distributions
• Updated NNLO QCD predictions for the weak radiative B-meson decays
• Exclusive radiative and electroweak b->d and b->s penguin decays at NLO
• B->V gamma Beyond QCD Factorisation
• The Radiative Decays B -> V gamma at Next-to-Leading Order in QCD
• Mixing-induced CP Asymmetries in Radiative B Decays in and beyond the Standard Model
• Selection and processing of calibration samples to measure the particle identification performance of the LHCb experiment in Run 2
• Flavour Changing Neutral Current Decays of Heavy Baryons: The Case ${\Lambda }_b\to \Lambda \gamma$
• Constraints on new physics from radiative $B$ decays
• Measurement of b-hadron fractions in 13 TeV pp collisions
• Rare baryon decays Lambda_b -> Lambda l+ l- (l=e, mu, tau) and Lambda_b -> Lambda gamma : Differential and total rates, lepton- and hadron-side forward-backward asymmetries
• Measurement of the $b$-quark production cross-section in 7 and 13 TeV $pp$ collisions
• Rare Decays of Λ_b->Λ+ γand Λ_b ->Λ+ l^{+} l^{-} in the Light-cone Sum Rules
• Precision Measurement of the B to X_s γPhoton Energy Spectrum, Branching Fraction, and Direct CP Asymmetry A_{CP}(B to X_{s+d}γ
• Effective Lagrangian Approach to Weak Radiative Decays of Heavy Hadrons
• Measurements of the Lambda_b0 -> J/psi Lambda decay amplitudes and the Lambda_b0 polarisation in pp collisions at sqrt(s) = 7 TeV
• Probing for New Physics in Polarized ${\Lambda }_b$ decays at the Z
• Angular analysis of the $B^0\to K^{\ast 0}{e}^{+}{e}^{-}$ decay in the low-$q^2$ region
• Heavy-to-light baryonic form factors at large recoil
• Long-distance effects in $B\to V\gamma$ radiative weak decays
• Measurement of the $\bar{B}\to X_s\gamma$ Branching Fraction with a Sum of Exclusive Decays
• Measurement of the ratio of branching fractions BR(B0 -> K*0 gamma)/BR(Bs0 -> phi gamma) and the direct CP asymmetry in B0 -> K*0 gamma
• Time-Dependent CP Asymmetries in B0 -> Ks pi0 gamma transitions
• Study of beauty hadron decays into pairs of charm hadrons
• CP asymmetry, branching ratios and isospin breaking effects of B -> K* gamma with the perturbative QCD approach
• The semi-leptonic and non-leptonic weak decays of ${\Lambda }_b^0$
• Evidence for Isospin Violation and Measurement of $CP$ Asymmetries in $B\to K^{\ast }(892)\gamma$
• First experimental study of photon polarization in radiative $B_s^0$ decays
• Rare ${\Lambda }_b\to \Lambda l^{+}{l}^{-}$ and ${\Lambda }_b\to \Lambda \gamma$ decays in the relativistic quark model
• Observation of the suppressed decay ${\Lambda }_b^0\to p{\pi }^{-}{\mu }^{+}{\mu }^{-}$
• Angular Distribution and Polarization of Photons in the Inclusive Decay ${\Lambda }_b\to X_s\gamma$
• Improved Light-cone QCD Sum Rule Analysis Of The Rare Decays ${\Lambda }_b\to \Lambda \gamma$ And ${\Lambda }_b\to \Lambda l^{+}{l}^{-}$
• Measurement of the ratio of branching fractions BR(B0 -> K*0 gamma)/BR(Bs0 -> phi gamma)
• Search for radiative b-hadron decays in proton-antiproton collisions at sqrt(s) = 1.8 TeV

Cited by in corpus (20)

• Averages of $b$-hadron, $c$-hadron, and $\tau$-lepton properties as of 2021
• Charmed Baryon Physics Circa 2021
• Flavor Anomalies in Heavy Quark Decays
• Heavy Flavour Physics and CP Violation at LHCb: a Ten-Year Review
• ${\Lambda }_b\to {\Lambda }^{\ast }(1520){\ell }^{+}{\ell }^{-}$ form factors from lattice QCD
• Dispersive bounds for local form factors in ${\Lambda }_b\to \Lambda$ transitions
• Measurement of the photon polarization in ${\Lambda }_b\to \Lambda \gamma$ decays
• Weak Radiative Decays of Anti-triplet Bottomed Baryons in Light-Front Quark Model
• Non-leptonic two-body decays of ${\Lambda }_b^0$ in light-front quark model
• Estimates of exchange topological contributions and $CP$-violating observables in ${\Lambda }_b\to \Lambda \varphi$ decay
• Flavor Physics at the CEPC: a General Perspective
• Radiative $b$-baryon decays to measure the photon and $b$-baryon polarization
• Rare ${\Lambda }_b\to \Lambda l^{+}{l}^{-}$ decay in the Bethe-Salpeter equation approach
• Heavy quark symmetry of ${\Lambda }_b^0$ decays in quark models
• Electroweak Penguin Decays of $b$-Flavoured Hadrons
• Studying Radiative Baryon Decays with the SU(3) Flavor Symmetry
• Rare radiative ${\Xi }_b^{-}\to {\Xi }^{-}\gamma$ decay in the relativistic quark model
• First search for the weak radiative decays ${\Lambda }_c^{+}\to {\Sigma }^{+}\gamma$ and ${\Xi }_c^0\to {\Xi }^0\gamma$
• ${\Xi }_b\to \Xi$ form factors from lattice QCD and Standard-Model predictions for ${\Xi }_b\to \Xi {\mu }^{+}{\mu }^{-}$ and ${\Xi }_b\to \Xi \gamma$ decays
• Forward-backward asymmetries in ${\Lambda }_b\to \Lambda l^{+}{l}^{-}$ in Bethe-Salpeter equation approach